WorldWideScience

Sample records for previously considered models

  1. A New Lagrangian Relaxation Method Considering Previous Hour Scheduling for Unit Commitment Problem

    Science.gov (United States)

    Khorasani, H.; Rashidinejad, M.; Purakbari-Kasmaie, M.; Abdollahi, A.

    2009-08-01

    Generation scheduling is a crucial challenge in power systems especially under new environment of liberalization of electricity industry. A new Lagrangian relaxation method for unit commitment (UC) has been presented for solving generation scheduling problem. This paper focuses on the economical aspect of UC problem, while the previous hour scheduling as a very important issue is studied. In this paper generation scheduling of present hour has been conducted by considering the previous hour scheduling. The impacts of hot/cold start-up cost have been taken in to account in this paper. Case studies and numerical analysis presents significant outcomes while it demonstrates the effectiveness of the proposed method.

  2. Previous Experience a Model of Practice UNAE

    OpenAIRE

    Ruiz, Ormary Barberi; Pesántez Palacios, María Dolores

    2017-01-01

    The statements presented in this article represents a preliminary version of the proposed model of pre-professional practices (PPP) of the National University of Education (UNAE) of Ecuador, an urgent institutional necessity is revealed in the descriptive analyzes conducted from technical support - administrative (reports, interviews, testimonials), pedagogical foundations of UNAE (curricular directionality, transverse axes in practice, career plan, approach and diagnostic examination as subj...

  3. A LCIA Model Considering Pollution Transfer Phenomena

    OpenAIRE

    Yu, Xi; Sekhari, Aicha; Nongaillard, Antoine; Bouras, Abdelaziz; Yu, Suiran; Yang, Qingyan

    2013-01-01

    Part 7: PLM and Influence of/from Social Networks; International audience; Due to market pressure and government regulations, environmental consciousness in manufacturing is becoming increasingly important. Currently, the global environmental impact (EI) of a product is a crucial criterion to judge its environmental performance. Many models were proposed in the last three decades to evaluate the global EI of products, but none of them considers the pollution transfer phenomena (PTP) of produc...

  4. The car following model considering traffic jerk

    Science.gov (United States)

    Ge, Hong-Xia; Zheng, Peng-jun; Wang, Wei; Cheng, Rong-Jun

    2015-09-01

    Based on optimal velocity car following model, a new model considering traffic jerk is proposed to describe the jamming transition in traffic flow on a highway. Traffic jerk means the sudden braking and acceleration of vehicles, which has a significant impact on traffic movement. The nature of the model is researched by using linear and nonlinear analysis method. A thermodynamic theory is formulated to describe the phase transition and critical phenomenon in traffic flow. The time-dependent Ginzburg-Landau (TDGL) equation and the modified Korteweg-de Vries (mKdV) equation are derived to describe the traffic flow near the critical point and the traffic jam. In addition, the connection between the TDGL and the mKdV equations are also given.

  5. Force Modelling in Orthogonal Cutting Considering Flank Wear Effect

    Science.gov (United States)

    Rathod, Kanti Bhikhubhai; Lalwani, Devdas I.

    2017-05-01

    In the present work, an attempt has been made to provide a predictive cutting force model during orthogonal cutting by combining two different force models, that is, a force model for a perfectly sharp tool plus considering the effect of edge radius and a force model for a worn tool. The first force model is for a perfectly sharp tool that is based on Oxley's predictive machining theory for orthogonal cutting as the Oxley's model is for perfectly sharp tool, the effect of cutting edge radius (hone radius) is added and improve model is presented. The second force model is based on worn tool (flank wear) that was proposed by Waldorf. Further, the developed combined force model is also used to predict flank wear width using inverse approach. The performance of the developed combined total force model is compared with the previously published results for AISI 1045 and AISI 4142 materials and found reasonably good agreement.

  6. Improved Generalized Force Model considering the Comfortable Driving Behavior

    Directory of Open Access Journals (Sweden)

    De-Jie Xu

    2015-01-01

    Full Text Available This paper presents an improved generalized force model (IGFM that considers the driver’s comfortable driving behavior. Through theoretical analysis, we propose the calculation methods of comfortable driving distance and velocity. Then the stability condition of the model is obtained by the linear stability analysis. The problems of the unrealistic acceleration of the leading car existing in the previous models were solved. Furthermore, the simulation results show that IGFM can predict correct delay time of car motion and kinematic wave speed at jam density, and it can exactly describe the driver’s behavior under an urgent case, where no collision occurs. The dynamic properties of IGFM also indicate that stability has improved compared to the generalized force model.

  7. An information propagation model considering incomplete reading behavior in microblog

    Science.gov (United States)

    Su, Qiang; Huang, Jiajia; Zhao, Xiande

    2015-02-01

    Microblog is one of the most popular communication channels on the Internet, and has already become the third largest source of news and public opinions in China. Although researchers have studied the information propagation in microblog using the epidemic models, previous studies have not considered the incomplete reading behavior among microblog users. Therefore, the model cannot fit the real situations well. In this paper, we proposed an improved model entitled Microblog-Susceptible-Infected-Removed (Mb-SIR) for information propagation by explicitly considering the user's incomplete reading behavior. We also tested the effectiveness of the model using real data from Sina Microblog. We demonstrate that the new proposed model is more accurate in describing the information propagation in microblog. In addition, we also investigate the effects of the critical model parameters, e.g., reading rate, spreading rate, and removed rate through numerical simulations. The simulation results show that, compared with other parameters, reading rate plays the most influential role in the information propagation performance in microblog.

  8. A deterministic aggregate production planning model considering quality of products

    International Nuclear Information System (INIS)

    Madadi, Najmeh; Wong, Kuan Yew

    2013-01-01

    Aggregate Production Planning (APP) is a medium-term planning which is concerned with the lowest-cost method of production planning to meet customers' requirements and to satisfy fluctuating demand over a planning time horizon. APP problem has been studied widely since it was introduced and formulated in 1950s. However, in several conducted studies in the APP area, most of the researchers have concentrated on some common objectives such as minimization of cost, fluctuation in the number of workers, and inventory level. Specifically, maintaining quality at the desirable level as an objective while minimizing cost has not been considered in previous studies. In this study, an attempt has been made to develop a multi-objective mixed integer linear programming model that serves those companies aiming to incur the minimum level of operational cost while maintaining quality at an acceptable level. In order to obtain the solution to the multi-objective model, the Fuzzy Goal Programming approach and max-min operator of Bellman-Zadeh were applied to the model. At the final step, IBM ILOG CPLEX Optimization Studio software was used to obtain the experimental results based on the data collected from an automotive parts manufacturing company. The results show that incorporating quality in the model imposes some costs, however a trade-off should be done between the cost resulting from producing products with higher quality and the cost that the firm may incur due to customer dissatisfaction and sale losses.

  9. Considering Late-Time Acceleration in Some Cosmological Models

    Directory of Open Access Journals (Sweden)

    S. Davood Sadatian

    2013-01-01

    Full Text Available We study two cosmological models: a nonminimally coupled scalar field on brane world model and a minimally coupled scalar field on Lorentz invariance violation model. We compare some cosmological results in these scenarios. Also, we consider some types of Rip singularity solution in both models.

  10. A model for voltage collapse study considering load characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, L.B. [Companhia de Energia Eletrica da Bahia (COELBA), Salvador, BA (Brazil)

    1994-12-31

    This paper presents a model for analysis of voltage collapse and instability problem considering the load characteristics. The model considers fundamentally the transmission lines represented by exact from through the generalized constants A, B, C, D and the loads as function of the voltage, emphasizing the cases of constant power, constant current and constant impedance. the study treats of the system behavior on steady state and presents illustrative graphics about the problem. (author) 12 refs., 4 figs.

  11. Lagrange multiplier for perishable inventory model considering warehouse capacity planning

    Science.gov (United States)

    Amran, Tiena Gustina; Fatima, Zenny

    2017-06-01

    This paper presented Lagrange Muktiplier approach for solving perishable raw material inventory planning considering warehouse capacity. A food company faced an issue of managing perishable raw materials and marinades which have limited shelf life. Another constraint to be considered was the capacity of the warehouse. Therefore, an inventory model considering shelf life and raw material warehouse capacity are needed in order to minimize the company's inventory cost. The inventory model implemented in this study was the adapted economic order quantity (EOQ) model which is optimized using Lagrange multiplier. The model and solution approach were applied to solve a case industry in a food manufacturer. The result showed that the total inventory cost decreased 2.42% after applying the proposed approach.

  12. Dynamic modeling of hydrostatic guideway considering compressibility and inertia effect

    Science.gov (United States)

    Du, Yikang; Mao, Kuanmin; Zhu, Yaming; Wang, Fengyun; Mao, Xiaobo; Li, Bin

    2015-03-01

    Hydrostatic guideways are used as an alternative to contact bearings due to high stiffness and high damping in heavy machine tools. To improve the dynamic characteristic of bearing structure, the dynamic modeling of the hydrostatic guidway should be accurately known. This paper presents a "mass-spring-Maxwell" model considering the effects of inertia, squeeze, compressibility and static bearing. To determine the dynamic model coefficients, numerical simulation of different cases between displacement and dynamic force of oil film are performed with fluent code. Simulation results show that hydrostatic guidway can be taken as a linear system when it is subjected to a small oscillation amplitude. Based on a dynamic model and numerical simulation, every dynamic model's parameters are calculated by the Levenberg-Marquardt algorithm. Identification results show that "mass-spring-damper" model is the most appropriate dynamic model of the hydrostatic guidway. This paper provides a reference and preparation for the analysis of the dynamic model of the similar hydrostatic bearings.

  13. [Lake eutrophication modeling in considering climatic factors change: a review].

    Science.gov (United States)

    Su, Jie-Qiong; Wang, Xuan; Yang, Zhi-Feng

    2012-11-01

    Climatic factors are considered as the key factors affecting the trophic status and its process in most lakes. Under the background of global climate change, to incorporate the variations of climatic factors into lake eutrophication models could provide solid technical support for the analysis of the trophic evolution trend of lake and the decision-making of lake environment management. This paper analyzed the effects of climatic factors such as air temperature, precipitation, sunlight, and atmosphere on lake eutrophication, and summarized the research results about the lake eutrophication modeling in considering in considering climatic factors change, including the modeling based on statistical analysis, ecological dynamic analysis, system analysis, and intelligent algorithm. The prospective approaches to improve the accuracy of lake eutrophication modeling with the consideration of climatic factors change were put forward, including 1) to strengthen the analysis of the mechanisms related to the effects of climatic factors change on lake trophic status, 2) to identify the appropriate simulation models to generate several scenarios under proper temporal and spatial scales and resolutions, and 3) to integrate the climatic factors change simulation, hydrodynamic model, ecological simulation, and intelligent algorithm into a general modeling system to achieve an accurate prediction of lake eutrophication under climatic change.

  14. Nonlinear Dynamic Model of PMBLDC Motor Considering Core Losses

    DEFF Research Database (Denmark)

    Fasil, Muhammed; Mijatovic, Nenad; Jensen, Bogi Bech

    2017-01-01

    The phase variable model is used commonly when simulating a motor drive system with a three-phase permanent magnet brushless DC (PMBLDC) motor. The phase variable model neglects core losses and this affects its accuracy when modelling fractional-slot machines. The inaccuracy of phase variable model...... of fractional-slot machines can be attributed to considerable armature flux harmonics, which causes an increased core loss. This study proposes a nonlinear phase variable model of PMBLDC motor that considers the core losses induced in the stator and the rotor. The core loss model is developed based...... on the detailed analysis of the flux path and the variation of flux in different components of the machine. A prototype of fractional slot axial flux PMBLDC in-wheel motor is used to assess the proposed nonlinear dynamic model....

  15. A new car-following model considering velocity anticipation

    International Nuclear Information System (INIS)

    Jun-Fang, Tian; Bin, Jia; Xin-Gang, Li; Zi-You, Gao

    2010-01-01

    The full velocity difference model proposed by Jiang et al. [2001 Phys. Rev. E 64 017101] has been improved by introducing velocity anticipation. Velocity anticipation means the follower estimates the future velocity of the leader. The stability condition of the new model is obtained by using the linear stability theory. Theoretical results show that the stability region increases when we increase the anticipation time interval. The mKdV equation is derived to describe the kink–antikink soliton wave and obtain the coexisting stability line. The delay time of car motion and kinematic wave speed at jam density are obtained in this model. Numerical simulations exhibit that when we increase the anticipation time interval enough, the new model could avoid accidents under urgent braking cases. Also, the traffic jam could be suppressed by considering the anticipation velocity. All results demonstrate that this model is an improvement on the full velocity difference model. (general)

  16. A new car-following model considering velocity anticipation

    Science.gov (United States)

    Tian, Jun-Fang; Jia, Bin; Li, Xin-Gang; Gao, Zi-You

    2010-01-01

    The full velocity difference model proposed by Jiang et al. [2001 Phys. Rev. E 64 017101] has been improved by introducing velocity anticipation. Velocity anticipation means the follower estimates the future velocity of the leader. The stability condition of the new model is obtained by using the linear stability theory. Theoretical results show that the stability region increases when we increase the anticipation time interval. The mKdV equation is derived to describe the kink-antikink soliton wave and obtain the coexisting stability line. The delay time of car motion and kinematic wave speed at jam density are obtained in this model. Numerical simulations exhibit that when we increase the anticipation time interval enough, the new model could avoid accidents under urgent braking cases. Also, the traffic jam could be suppressed by considering the anticipation velocity. All results demonstrate that this model is an improvement on the full velocity difference model.

  17. CAN “THE IDEAL” ECONOMIC MODELS BE CONSIDERED COMPREHENSIBLE ?!

    Directory of Open Access Journals (Sweden)

    A.A. Kuklin

    2006-03-01

    Full Text Available This article opens the cycle of authors’ publications on the questions of theoretical approaches and representations of systems’ economics development. Digression of origin and development of social-economical formations is given. The attempt to consider the transformation of systems’ economics with the consideration of latent dynamic characteristics, to reveal the laws of structural-genetic and functional attribute of changing economy forming was made. Also it is offered to consider the models of systems’ economics transformation and their influence on territorial economic safety of different level.

  18. Bayesian tsunami fragility modeling considering input data uncertainty

    OpenAIRE

    De Risi, Raffaele; Goda, Katsu; Mori, Nobuhito; Yasuda, Tomohiro

    2017-01-01

    Empirical tsunami fragility curves are developed based on a Bayesian framework by accounting for uncertainty of input tsunami hazard data in a systematic and comprehensive manner. Three fragility modeling approaches, i.e. lognormal method, binomial logistic method, and multinomial logistic method, are considered, and are applied to extensive tsunami damage data for the 2011 Tohoku earthquake. A unique aspect of this study is that uncertainty of tsunami inundation data (i.e. input hazard data ...

  19. Rumor spreading model considering hesitating mechanism in complex social networks

    Science.gov (United States)

    Xia, Ling-Ling; Jiang, Guo-Ping; Song, Bo; Song, Yu-Rong

    2015-11-01

    The study of rumor spreading has become an important issue on complex social networks. On the basis of prior studies, we propose a modified ​susceptible-exposed-infected-removed (SEIR) model with hesitating mechanism by considering the attractiveness and fuzziness of the content of rumors. We derive mean-field equations to characterize the dynamics of SEIR model on both homogeneous and heterogeneous networks. Then a steady-state analysis is conducted to investigate the spreading threshold and the final rumor size. Simulations on both artificial and real networks show that a decrease of fuzziness can effectively increase the spreading threshold of the SEIR model and reduce the maximum rumor influence. In addition, the spreading threshold is independent of the attractiveness of rumor. Simulation results also show that the speed of rumor spreading obeys the relation ;BA network > WS network;, whereas the final scale of spreading obeys the opposite relation.

  20. Hysteretic Models Considering Axial-Shear-Flexure Interaction

    Science.gov (United States)

    Ceresa, Paola; Negrisoli, Giorgio

    2017-10-01

    Most of the existing numerical models implemented in finite element (FE) software, at the current state of the art, are not capable to describe, with enough reliability, the interaction between axial, shear and flexural actions under cyclic loading (e.g. seismic actions), neglecting crucial effects for predicting the nature of the collapse of reinforced concrete (RC) structural elements. Just a few existing 3D volume models or fibre beam models can lead to a quite accurate response, but they are still computationally inefficient for typical applications in earthquake engineering and also characterized by very complex formulation. Thus, discrete models with lumped plasticity hinges may be the preferred choice for modelling the hysteretic behaviour due to cyclic loading conditions, in particular with reference to its implementation in a commercial software package. These considerations lead to this research work focused on the development of a model for RC beam-column elements able to consider degradation effects and interaction between the actions under cyclic loading conditions. In order to develop a model for a general 3D discrete hinge element able to take into account the axial-shear-flexural interaction, it is necessary to provide an implementation which involves a corrector-predictor iterative scheme. Furthermore, a reliable constitutive model based on damage plasticity theory is formulated and implemented for its numerical validation. Aim of this research work is to provide the formulation of a numerical model, which will allow implementation within a FE software package for nonlinear cyclic analysis of RC structural members. The developed model accounts for stiffness degradation effect and stiffness recovery for loading reversal.

  1. A modified two-lane traffic model considering drivers' personality

    Science.gov (United States)

    Zhu, H. B.; Zhang, N. X.; Wu, W. J.

    2015-06-01

    Based on the two-lane traffic model proposed by Chowdhury et al., a modified traffic model (R-STCA model, for short) is presented, in which the new symmetric lane changing rules are introduced by considering driving behavioral difference and dynamic headway. After the numerical simulation, a broad scattering of simulated points is exhibited in the moderate density region on the flow-density plane. The synchronized flow phase accompanied with the wide moving jam phase is reproduced. The spatial-temporal profiles indicate that the vehicles move according to the R-STCA model can change lane more easily and more realistically. Then vehicles are convenient to get rid of the slow vehicles that turn into plugs ahead, and hence the capacity increases. Furthermore the phenomenon of the high speed car-following is discovered by using the R-STCA model, which has been already observed in the traffic measured data. All these results indicate that the presented model is reasonable and more realistic.

  2. Modeling of flexible reciprocating compressor considering the crosshead subsidence

    Science.gov (United States)

    Xue, Xiaogang; Liu, Shulin; Sun, Xin

    2018-01-01

    Crank-slider mechanisms are important parts of heavy duty machines, including reciprocating compressors, combustion motors. This paper targets on the dynamic response of the crosshead in a reciprocating compressor, taking into consideration the crosshead deviation from the original level. The traditional model of the compressor is usually a slider-mechanism system without considering the deflection of the crosshead, thus neglecting the influence of the piston rod, which has some flexible features. In this paper, a rigid-flexible model of slider-crank is described theoretically, using the commercial software MATLAB, where the crank, connecting rod and crosshead are treated as rigid bodies, while the piston rod connected to the crosshead is considered as a flexible body. The dynamic response of the mechanism with the crosshead subsidence is discussed detailedly in this paper. After calculated theoretically, the MATLAB simulation showed that the dynamic response of the crosshead will be greatly influenced if the crosshead subsided from the original level. Also, the influence of the crosshead subsidence was also investigated, and some extra vibration of the crosshead arises.

  3. Improving large-scale groundwater models by considering fossil gradients

    Science.gov (United States)

    Schulz, Stephan; Walther, Marc; Michelsen, Nils; Rausch, Randolf; Dirks, Heiko; Al-Saud, Mohammed; Merz, Ralf; Kolditz, Olaf; Schüth, Christoph

    2017-05-01

    Due to limited availability of surface water, many arid to semi-arid countries rely on their groundwater resources. Despite the quasi-absence of present day replenishment, some of these groundwater bodies contain large amounts of water, which was recharged during pluvial periods of the Late Pleistocene to Early Holocene. These mostly fossil, non-renewable resources require different management schemes compared to those which are usually applied in renewable systems. Fossil groundwater is a finite resource and its withdrawal implies mining of aquifer storage reserves. Although they receive almost no recharge, some of them show notable hydraulic gradients and a flow towards their discharge areas, even without pumping. As a result, these systems have more discharge than recharge and hence are not in steady state, which makes their modelling, in particular the calibration, very challenging. In this study, we introduce a new calibration approach, composed of four steps: (i) estimating the fossil discharge component, (ii) determining the origin of fossil discharge, (iii) fitting the hydraulic conductivity with a pseudo steady-state model, and (iv) fitting the storage capacity with a transient model by reconstructing head drawdown induced by pumping activities. Finally, we test the relevance of our approach and evaluated the effect of considering or ignoring fossil gradients on aquifer parameterization for the Upper Mega Aquifer (UMA) on the Arabian Peninsula.

  4. A thermo-elastic model for soft rocks considering structure

    International Nuclear Information System (INIS)

    He, Z.; Zhang, S.; Teng, J.; Xiong, Y.

    2017-01-01

    In the fields of nuclear waste geological deposit, geothermal energy and deep mining, the effects of temperature on the mechanical behaviors of soft rocks cannot be neglected. Experimental data in the literature also showed that the structure of soft rocks cannot be ignored. Based on the super-loading yield surface and the concept of temperature-deduced equivalent stress, a thermo-elastoplastic model for soft rocks is proposed considering the structure. Compared to the super-loading yield surface, only one parameter is added, i.e. the linear thermal expansion coefficient. The predicted results and the comparisons with experimental data in the literature show that the proposed model is capable of simultaneously describing heat increase and heat decrease of soft rocks. A stronger initial structure leads to a greater strength of the soft rocks. Heat increase and heat decrease can be converted between each other due to the change of the initial structure of soft rocks. Furthermore, regardless of the heat increase or heat decrease, a larger linear thermal expansion coefficient or a greater temperature always leads to a much rapider degradation of the structure. The degradation trend will be more obvious for the coupled greater values of linear thermal expansion coefficient and temperature. Lastly, compared to heat decrease, the structure will degrade more easily in the case of heat increase. (authors)

  5. A thermo-elastoplastic model for soft rocks considering structure

    Science.gov (United States)

    He, Zuoyue; Zhang, Sheng; Teng, Jidong; Xiong, Yonglin

    2017-11-01

    In the fields of nuclear waste geological deposit, geothermy and deep mining, the effects of temperature on the mechanical behaviors of soft rocks cannot be neglected. Experimental data in the literature also showed that the structure of soft rocks cannot be ignored. Based on the superloading yield surface and the concept of temperature-deduced equivalent stress, a thermo-elastoplastic model for soft rocks is proposed considering the structure. Compared to the superloading yield surface, only one parameter is added, i.e. the linear thermal expansion coefficient. The predicted results and the comparisons with experimental data in the literature show that the proposed model is capable of simultaneously describing heat increase and heat decrease of soft rocks. A stronger initial structure leads to a greater strength of the soft rocks. Heat increase and heat decrease can be converted between each other due to the change of the initial structure of soft rocks. Furthermore, regardless of the heat increase or heat decrease, a larger linear thermal expansion coefficient or a greater temperature always leads to a much rapider degradation of the structure. The degradation trend will be more obvious for the coupled greater values of linear thermal expansion coefficient and temperature. Lastly, compared to heat decrease, the structure will degrade more easily in the case of heat increase.

  6. Land use allocation model considering climate change impact

    Science.gov (United States)

    Lee, D. K.; Yoon, E. J.; Song, Y. I.

    2017-12-01

    In Korea, climate change adaptation plans are being developed for each administrative district based on impact assessments constructed in various fields. This climate change impact assessments are superimposed on the actual space, which causes problems in land use allocation because the spatial distribution of individual impacts may be different each other. This implies that trade-offs between climate change impacts can occur depending on the composition of land use. Moreover, the actual space is complexly intertwined with various factors such as required area, legal regulations, and socioeconomic values, so land use allocation in consideration of climate change can be very difficult problem to solve (Liu et al. 2012; Porta et al. 2013).Optimization techniques can generate a sufficiently good alternatives for land use allocation at the strategic level if only the fitness function of relationship between impact and land use composition are derived. It has also been noted that land use optimization model is more effective than the scenario-based prediction model in achieving the objectives for problem solving (Zhang et al. 2014). Therefore in this study, we developed a quantitative tool, MOGA (Multi Objective Genetic Algorithm), which can generate a comprehensive land use allocations considering various climate change impacts, and apply it to the Gangwon-do in Korea. Genetic Algorithms (GAs) are the most popular optimization technique to address multi-objective in land use allocation. Also, it allows for immediate feedback to stake holders because it can run a number of experiments with different parameter values. And it is expected that land use decision makers and planners can formulate a detailed spatial plan or perform additional analysis based on the result of optimization model. Acknowledgments: This work was supported by the Korea Ministry of Environment (MOE) as "Climate Change Correspondence Program (Project number: 2014001310006)"

  7. The role of a specialized approach for patients with diabetes, critical ischaemia and foot ulcers not previously considered for proactive management.

    Science.gov (United States)

    Aragón-Sánchez, J; Maynar-Moliner, M; Pulido-Duque, J M; Rabellino, M; González, G; Zander, T

    2011-10-01

    To analyse the outcome of the proactive management of patients with diabetes, critical limb ischaemia and foot ulcers using percutaneous transluminal angioplasty as the only vascular procedure and adjuvant conservative surgery when indicated. A retrospective study of patients with diabetes included in our database who sought a second opinion in our unit and met the following criteria: foot ulcer and critical limb ischaemia in patients for whom any proactive vascular treatment had not previously been considered by other teams. Twenty patients underwent endovascular procedures. Success was achieved in 19 cases (95%). No post-operative mortality (within 30 days after the procedure) was found. Additional surgery was required in eight cases (40%): one calcaneal ostectomy and seven minor amputations. The need for surgery was associated with infection (P diabetes, foot ulcers and critical limb ischaemia by means of a proactive approach including endovascular procedures in specialized settings provides a high rate of limb salvage. This may result in lowering the number of lower limb amputations in our community. © 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.

  8. EPR-based material modelling of soils considering volume changes

    Science.gov (United States)

    Faramarzi, Asaad; Javadi, Akbar A.; Alani, Amir M.

    2012-11-01

    In this paper an approach is presented for developing material models for soils based on evolutionary polynomial regression (EPR), taking into account its volumetric behaviour. EPR is a recently developed hybrid data mining technique that searches for structured mathematical equations (representing the behaviour of a system) using genetic algorithm and the least squares method. Stress-strain data from triaxial test are used to train and develop EPR-based material models for soil. The developed models are compared with some of the well known conventional material models. In particular, the capability of the developed EPR models in predicting volume change behaviour of soils is illustrated. It is also shown that the developed EPR-based material models can be incorporated in finite element (FE) analysis. Two geotechnical examples are presented to verify the developed EPR-based FE model (EPR-FEM). The results of the EPR-FEM are compared with those of a standard FEM where conventional constitutive models are used to describe the material behaviour. The results show that EPR-FEM can be successfully employed to analyse geotechnical engineering problems. The advantages of the proposed EPR models are highlighted.

  9. Numerical Modelling of River Captures Considering Hillslope Processes

    Science.gov (United States)

    Schroeder, S.; Gloaguen, R.

    2016-12-01

    River capturing events are assumed to occur in highly tectonically uplifted regions. Thus, a sedimentary terrace that is tilted against the current river flow direction could either be interpreted as tectonically uplifted or could be effected by a river capturing event . Many observations could be misinterpreted as signs for capturings. A better understanding of the reasons for river capturing may help to reject or validate particular river capturing hypotheses. In our numerical study, we investigate the impact of different parameters on the probability of river capturings. We model a developing river network along fault-bounded block rotations with different deflection angles and high erodibility zones. The models confirm the hypothesis that a sudden base level drop may lead to a chain reaction of river capturings. Extracted longitudinal stream profiles highlight the modelled knickpoint migration velocity after a capturing event: The next event follows within a short period of time. Our models suggest that the probability of a capturing event mainly depends on the uplift rate rather than on the fault erodibility. However, the fault erodibility controls the capturing velocity. Furthermore, we conclude that the angle between a fault and a crossing river determines the capturing probability. Presented models are computed with the supply-limited SEC DANSER. It models long range transport with the stream power law as well as short range transport with (non-)linear diffusion. Separating fluvial and hillslope processes (incision threshold) hinders river capturing in low resolution models. DANSER is able to solve this challenge with the lateral incision algorithm.

  10. Stochastic hyperelastic modeling considering dependency of material parameters

    Science.gov (United States)

    Caylak, Ismail; Penner, Eduard; Dridger, Alex; Mahnken, Rolf

    2018-03-01

    This paper investigates the uncertainty of a hyperelastic model by treating random material parameters as stochastic variables. For its stochastic discretization a polynomial chaos expansion (PCE) is used. An important aspect in our work is the consideration of stochastic dependencies in the stochastic modeling of Ogden's material model. To this end, artificial experiments are generated using the auto-regressive moving average process based on real experiments. The parameter identification for all data provides statistics of Ogden's material parameters, which are subsequently used for stochastic modeling. Stochastic dependencies are incorporated into the PCE using a Nataf transformation from dependent distributed random variables to independent standard normal distributed ones. The representative numerical example shows that our proposed method adequately takes into account the stochastic dependencies of Ogden's material parameters.

  11. Considering Planetary Constraints and Dynamic Screening in Solar Evolution Modeling

    Science.gov (United States)

    Wood, Suzannah R.; Mussack, Katie; Guzik, Joyce A.

    2018-01-01

    The ‘faint early sun problem’ remains unsolved. This problem consists of the apparent contradiction between the standard solar model prediction of lower luminosity (70% of current luminosity) and the observations of liquid water on early Earth and Mars. The presence of liquid water on early Earth and Mars should not be neglected and should be used as a constraint for solar evolution modeling. In addition, modifications to standard solar models are needed to address the discrepancy with solar structure inferred from helioseismology given the latest solar abundance determinations. Here, we will utilize the three different solar abundances: GN93 (Grevesse & Noels, 1993), AGS05 (Asplund et al., 2005), AGSS09 (Asplund et al., 2009). Here, we propose an early mass loss model with an initial solar mass between 1.07 and 1.15 solar masses and an exponentially decreasing mass-loss rate to meet conditions in the early solar system (Wood et al, submitted). Additionally, we investigate the effects of dynamic screening and the new OPLIB opacities from Los Alamos (Colgan et al., 2016). We show the effects of these modifications to the standard solar evolution models on the interior structure, neutrino fluxes, sound speed, p-mode frequencies, convection zone depth, and envelope helium and element abundance of the model sun at the present day.

  12. Hybrid Corporate Performance Prediction Model Considering Technical Capability

    Directory of Open Access Journals (Sweden)

    Joonhyuck Lee

    2016-07-01

    Full Text Available Many studies have tried to predict corporate performance and stock prices to enhance investment profitability using qualitative approaches such as the Delphi method. However, developments in data processing technology and machine-learning algorithms have resulted in efforts to develop quantitative prediction models in various managerial subject areas. We propose a quantitative corporate performance prediction model that applies the support vector regression (SVR algorithm to solve the problem of the overfitting of training data and can be applied to regression problems. The proposed model optimizes the SVR training parameters based on the training data, using the genetic algorithm to achieve sustainable predictability in changeable markets and managerial environments. Technology-intensive companies represent an increasing share of the total economy. The performance and stock prices of these companies are affected by their financial standing and their technological capabilities. Therefore, we apply both financial indicators and technical indicators to establish the proposed prediction model. Here, we use time series data, including financial, patent, and corporate performance information of 44 electronic and IT companies. Then, we predict the performance of these companies as an empirical verification of the prediction performance of the proposed model.

  13. Market Model Considering Bilateral Transactions in the Deregulated Electricity Market

    Science.gov (United States)

    Ruiz Monroy, José Joaquín; Kita, Hiroyuki; Tanaka, Eiichi; Hasegawa, Jun

    This paper proposes an algorithm to simulate the transactions that take place in a free market of electricity. The algorithm presented is used for Bilateral Transaction Matrix (BTM) creation assuming that a day ahead load forecast is previously known. Bids can be made by both the generation side and the demand side to determine transaction prices, then the algorithm allocates the transactions according to market rules until the demand is satisfied. This creates feasible BTMs that can be used to study system security and to find future methods to regulate bilateral transactions through market mechanisms like the application of penalties to the transactions that affect the system’s security. Results show that the proposed algorithm is a good option for electricity market analysis. The proposed algorithm provides system planners with a practical tool for data creation to further study the effects of bilateral transactions in a deregulated electricity market.

  14. An extended car-following model considering the acceleration derivative in some typical traffic environments

    Science.gov (United States)

    Zhou, Tong; Chen, Dong; Liu, Weining

    2018-03-01

    Based on the full velocity difference and acceleration car-following model, an extended car-following model is proposed by considering the vehicle’s acceleration derivative. The stability condition is given by applying the control theory. Considering some typical traffic environments, the results of theoretical analysis and numerical simulation show the extended model has a more actual acceleration of string vehicles than that of the previous models in starting process, stopping process and sudden brake. Meanwhile, the traffic jams more easily occur when the coefficient of vehicle’s acceleration derivative increases, which is presented by space-time evolution. The results confirm that the vehicle’s acceleration derivative plays an important role in the traffic jamming transition and the evolution of traffic congestion.

  15. Comparative assessment of PV plant performance models considering climate effects

    DEFF Research Database (Denmark)

    Tina, Giuseppe; Ventura, Cristina; Sera, Dezso

    2017-01-01

    . The methodological approach is based on comparative tests of the analyzed models applied to two PV plants installed respectively in north of Denmark (Aalborg) and in the south of Italy (Agrigento). The different ambient, operating and installation conditions allow to understand how these factors impact the precision...

  16. A Unified Elastoplastic Model of Unsaturated Soils Considering Capillary Hysteresis

    Directory of Open Access Journals (Sweden)

    Tiantian Ma

    2013-01-01

    Full Text Available Unlike its saturated counterparts, the mechanical behavior of an unsaturated soil depends not only upon its stress history but also upon its hydraulic history. In this paper, a soil-water characteristic relationship which is capable of describing the effect of capillary hysteresis is introduced to characterize the influence of hydraulic history on the skeletal deformation. The capillary hysteresis is viewed as a phenomenon associated with the internal structural rearrangements in unsaturated soils, which can be characterized by using a set of internal state variables. It is shown that both capillary hysteresis and plastic deformation can be consistently addressed in a unified theoretical framework. Within this context, a constitutive model of unsaturated soils is developed by generalizing the modified Cam-Clay model. A hardening function is introduced, in which both the matric suction and the degree of saturation are explicitly included as hardening variables, so that the effect of hydraulic history on the mechanical response can be properly addressed. The proposed model is capable of capturing the main features of the unsaturated soil behavior. The new model has a hierarchical structure, and, depending upon application, it can describe the stress-strain relation and the soil-water characteristics in a coupled or uncoupled manner.

  17. Modelling of capital asset pricing by considering the lagged effects

    Science.gov (United States)

    Sukono; Hidayat, Y.; Bon, A. Talib bin; Supian, S.

    2017-01-01

    In this paper the problem of modelling the Capital Asset Pricing Model (CAPM) with the effect of the lagged is discussed. It is assumed that asset returns are analysed influenced by the market return and the return of risk-free assets. To analyse the relationship between asset returns, the market return, and the return of risk-free assets, it is conducted by using a regression equation of CAPM, and regression equation of lagged distributed CAPM. Associated with the regression equation lagged CAPM distributed, this paper also developed a regression equation of Koyck transformation CAPM. Results of development show that the regression equation of Koyck transformation CAPM has advantages, namely simple as it only requires three parameters, compared with regression equation of lagged distributed CAPM.

  18. Considering extraction constraints in long-term oil price modelling

    International Nuclear Information System (INIS)

    Rehrl, Tobias; Friedrich, Rainer; Voss, Alfred

    2005-01-01

    Apart from divergence about the remaining global oil resources, the peak oil discussion can be reduced to a dispute about the time rate at which these resources can be supplied. On the one hand it is problematic to project oil supply trends without taking both - prices as well as supply costs - explicitly into account. On the other hand are supply cost estimates however itself heavily dependent on the underlying extraction rates and are actually only valid within a certain business-as-usual extraction rate scenario (which itself is the task to determine). In fact, even after having applied enhanced recovery technologies, the rate at which an oil field can be exploited is quite restricted. Above a certain level an additional extraction rate increase can only be costly achieved at risks of losses in the overall recoverable amounts of the oil reservoir and causes much higher marginal cost. This inflexibility in extraction can be overcome in principle by the access to new oil fields. This indicates why the discovery trend may roughly form the long-term oil production curve, at least for price-taking suppliers. The long term oil discovery trend itself can be described as a logistic process with the two opposed effects of learning and depletion. This leads to the well-known Hubbert curve. Several attempts have been made to incorporate economic variables econometrically into the Hubbert model. With this work we follow a somewhat inverse approach and integrate Hubbert curves in our Long-term Oil Price and EXtraction model LOPEX. In LOPEX we assume that non-OPEC oil production - as long as the oil can be profitably discovered and extracted - is restricted to follow self-regulative discovery trends described by Hubbert curves. Non-OPEC production in LOPEX therefore consists of those Hubbert cycles that are profitable, depending on supply cost and price. Endogenous and exogenous technical progress is extra integrated in different ways. LOPEX determines extraction and price

  19. Simplified Modeling of Tropospheric Ozone Formation Considering Alternative Fuels Using

    Directory of Open Access Journals (Sweden)

    Leonardo Aragão Ferreira da Silva

    2014-07-01

    Full Text Available Brazilian cities have been constantly exposed to air quality episodes of high ozone concentrations (O3 . Known for not be emitted directly into the environment, O3 is a result of several chemical reactions of other pollutants emitted to atmosphere. The growth of vehicle fleet and government incentives for using alternative fuels like ethanol and Compressed Natural Gas (CNG are changing the Brazilian Metropolitan Areas in terms of acetaldehyde and formaldehyde emissions, Volatile Organic Compounds (VOC's present in the atmosphere and known to act on the kinetics of ozone. Driven by high concentrations of tropospheric ozone in urban/industry centers and its implications for environment and population health, the target of this work is understand the kinetics of ozone formation through the creation of a mathematical model in FORTRAN 90, describing a system of coupled ordinary differential equations able to represent a simplified mechanism of photochemical reactions in the Brazilian Metropolitan Area. Evaluating the concentration results of each pollutant were possible to observe the precursor’s influence on tropospheric ozone formation, which seasons were more conducive to this one and which are the influences of weather conditions on formation of photochemical smog.

  20. Modeling of detective quantum efficiency considering scatter-reduction devices

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Woong; Kim, Dong Woon; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of)

    2016-05-15

    The reduction of signal-to-noise ratio (SNR) cannot be restored and thus has become a severe issue in digital mammography.1 Therefore, antiscatter grids are typically used in mammography. Scatter-cleanup performance of various scatter-reduction devices, such as air gaps,2 linear (1D) or cellular (2D) grids,3, 4 and slot-scanning devices,5 has been extensively investigated by many research groups. In the present time, a digital mammography system with the slotscanning geometry is also commercially available.6 In this study, we theoretically investigate the effect of scattered photons on the detective quantum efficiency (DQE) performance of digital mammography detectors by using the cascaded-systems analysis (CSA) approach. We show a simple DQE formalism describing digital mammography detector systems equipped with scatter reduction devices by regarding the scattered photons as additive noise sources. The LFD increased with increasing PMMA thickness, and the amounts of LFD indicated the corresponding SF. The estimated SFs were 0.13, 0.21, and 0.29 for PMMA thicknesses of 10, 20, and 30 mm, respectively. While the solid line describing the measured MTF for PMMA with 0 mm was the result of least-squares of regression fit using Eq. (14), the other lines were simply resulted from the multiplication of the fit result (for PMMA with 0 mm) with the (1-SF) estimated from the LFDs in the measured MTFs. Spectral noise-power densities over the entire frequency range were not much changed with increasing scatter. On the other hand, the calculation results showed that the spectral noise-power densities increased with increasing scatter. This discrepancy may be explained by that the model developed in this study does not account for the changes in x-ray interaction parameters for varying spectral shapes due to beam hardening with increasing PMMA thicknesses.

  1. Ion current prediction model considering columnar recombination in alpha radioactivity measurement using ionized air transportation

    International Nuclear Information System (INIS)

    Naito, Susumu; Hirata, Yosuke; Izumi, Mikio; Sano, Akira; Miyamoto, Yasuaki; Aoyama, Yoshio; Yamaguchi, Hiromi

    2007-01-01

    We present a reinforced ion current prediction model in alpha radioactivity measurement using ionized air transportation. Although our previous model explained the qualitative trend of the measured ion current values, the absolute values of the theoretical curves were about two times as large as the measured values. In order to accurately predict the measured values, we reinforced our model by considering columnar recombination and turbulent diffusion, which affects columnar recombination. Our new model explained the considerable ion loss in the early stage of ion diffusion and narrowed the gap between the theoretical and measured values. The model also predicted suppression of ion loss due to columnar recombination by spraying a high-speed air flow near a contaminated surface. This suppression was experimentally investigated and confirmed. In conclusion, we quantitatively clarified the theoretical relation between alpha radioactivity and ion current in laminar flow and turbulent pipe flow. (author)

  2. A structural constitutive model considering angular dispersion and waviness of collagen fibres of rabbit facial veins

    Directory of Open Access Journals (Sweden)

    Stergiopulos Nikos

    2011-03-01

    Full Text Available Abstract Background Structural constitutive models of vascular wall integrate information on composition and structural arrangements of tissue. In blood vessels, collagen fibres are arranged in coiled and wavy bundles and the individual collagen fibres have a deviation from their mean orientation. A complete structural constitutive model for vascular wall should incorporate both waviness and orientational distribution of fibres. We have previously developed a model, for passive properties of vascular wall, which considers the waviness of collagen fibres. However, to our knowledge there is no structural model of vascular wall which integrates both these features. Methods In this study, we have suggested a structural strain energy function that incorporates not only the waviness but also the angular dispersion of fibres. We studied the effect of parameters related to the orientational distribution on macro-mechanical behaviour of tissue during inflation-extension tests. The model was further applied on experimental data from rabbit facial veins. Results Our parametric study showed that the model is less sensitive to the orientational dispersion when fibres are mainly oriented circumferentially. The macro-mechanical response is less sensitive to changes in the mean orientation when fibres are more dispersed. The model accurately fitted the experimental data of veins, while not improving the quality of the fit compared to the model without dispersion. Our results showed that the orientational dispersion of collagen fibres could be compensated by a less abrupt and shifted to higher strain collagen engagement pattern. This should be considered when the model is fitted to experimental data and model parameters are used to study structural modifications of collagen fibre network in physiology and disease. Conclusions The presented model incorporates structural features related to waviness and orientational distribution of collagen fibres and thus offers

  3. Rumor spreading model considering the activity of spreaders in the homogeneous network

    Science.gov (United States)

    Huo, Liang'an; Wang, Li; Song, Naixiang; Ma, Chenyang; He, Bing

    2017-02-01

    There are some similarities between the rumor spreading and the infectious disease transmission. In this paper, we investigate rumor spreading dynamics with the activity of spreaders based on compartment model in the homogeneous network. Different from previous studies, each spreader individual in network rotates between high active and low active state according to certain probabilities. We introduce a dynamic model for the rumor spreading called I2SR, in which we consider the activity of nodes and divide spreaders into spreaders with the high rate of active state and the low rate of active spreaders. Then, the locally asymptotic stability of equilibrium is established by using Routh-Hurwitz criteria. The global stability of internal equilibrium of model is proved based on Lasalle's invariance principle. Finally, numerical simulations are carried to illustrate the impact of different parameters on the rumor spreading.

  4. Modeling and experimental validation of a linear ultrasonic motor considering rough surface contact

    Science.gov (United States)

    Lv, Qibao; Yao, Zhiyuan; Li, Xiang

    2017-04-01

    Linear ultrasonic motor is driven by the interface friction between the stator and the slider. The performance of the motor is significantly affected by the contact state between the stator and slider which depends considerably on the morphology of the contact interface. A novel fiction model is developed to evaluate the output characteristics of a linear ultrasonic motor. The proposed model, where the roughness and plastic deformation of contact surfaces are considered, differs from the previous spring model. Based on the developed model, the effects of surface roughness parameters on motor performance are investigated. The behavior of the force transmission between the stator and the slider is studied to understand the driving mechanism. Furthermore, a comparison between the proposed model and the spring model is made. An experiment is designed to verify the feasibility and effectiveness of this proposed model by comparing the simulation results with the measured one. The results show that the proposed model is more accurate than the spring model. These discussions will be very useful for the improvement of control and the optimal design of linear ultrasonic motor.

  5. Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms.

    Science.gov (United States)

    Guo, Chaohua; Wei, Mingzhen; Liu, Hong

    2015-01-01

    Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production.

  6. Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms.

    Directory of Open Access Journals (Sweden)

    Chaohua Guo

    Full Text Available Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production.

  7. Validation of SWAT+ at field level and comparison with previous SWAT models in simulating hydrologic quantity

    Science.gov (United States)

    GAO, J.; White, M. J.; Bieger, K.; Yen, H.; Arnold, J. G.

    2017-12-01

    Over the past 20 years, the Soil and Water Assessment Tool (SWAT) has been adopted by many researches to assess water quantity and quality in watersheds around the world. As the demand increases in facilitating model support, maintenance, and future development, the SWAT source code and data have undergone major modifications over the past few years. To make the model more flexible in terms of interactions of spatial units and processes occurring in watersheds, a completely revised version of SWAT (SWAT+) was developed to improve SWAT's ability in water resource modelling and management. There are only several applications of SWAT+ in large watersheds, however, no study pays attention to validate the new model at field level and assess its performance. To test the basic hydrologic function of SWAT+, it was implemented in five field cases across five states in the U.S. and compared the SWAT+ created results with that from the previous models at the same fields. Additionally, an automatic calibration tool was used to test which model is easier to be calibrated well in a limited number of parameter adjustments. The goal of the study was to evaluate the performance of SWAT+ in simulating stream flow on field level at different geographical locations. The results demonstrate that SWAT+ demonstrated similar performance with previous SWAT model, but the flexibility offered by SWAT+ via the connection of different spatial objects can result in a more accurate simulation of hydrological processes in spatial, especially for watershed with artificial facilities. Autocalibration shows that SWAT+ is much easier to obtain a satisfied result compared with the previous SWAT. Although many capabilities have already been enhanced in SWAT+, there exist inaccuracies in simulation. This insufficiency will be improved with advancements in scientific knowledge on hydrologic process in specific watersheds. Currently, SWAT+ is prerelease, and any errors are being addressed.

  8. Future bloom and blossom frost risk for Malus domestica considering climate model and impact model uncertainties.

    Directory of Open Access Journals (Sweden)

    Holger Hoffmann

    Full Text Available The future bloom and risk of blossom frosts for Malus domestica were projected using regional climate realizations and phenological ( = impact models. As climate impact projections are susceptible to uncertainties of climate and impact models and model concatenation, the significant horizon of the climate impact signal was analyzed by applying 7 impact models, including two new developments, on 13 climate realizations of the IPCC emission scenario A1B. Advancement of phenophases and a decrease in blossom frost risk for Lower Saxony (Germany for early and late ripeners was determined by six out of seven phenological models. Single model/single grid point time series of bloom showed significant trends by 2021-2050 compared to 1971-2000, whereas the joint signal of all climate and impact models did not stabilize until 2043. Regarding blossom frost risk, joint projection variability exceeded the projected signal. Thus, blossom frost risk cannot be stated to be lower by the end of the 21st century despite a negative trend. As a consequence it is however unlikely to increase. Uncertainty of temperature, blooming date and blossom frost risk projection reached a minimum at 2078-2087. The projected phenophases advanced by 5.5 d K(-1, showing partial compensation of delayed fulfillment of the winter chill requirement and faster completion of the following forcing phase in spring. Finally, phenological model performance was improved by considering the length of day.

  9. An Integrated Decentralized Energy Planning Model considering Demand-Side Management and Environmental Measures

    Directory of Open Access Journals (Sweden)

    Seyed Mahmood Kazemi

    2013-01-01

    Full Text Available Decentralized energy planning (DEP is looked upon as an indisputable opportunity for energy planning of villages, isolated islands, and far spots. Nonetheless, at this decentralized planning level, the value of demand-side resources is not fairly examined, despite enjoying great advantages. Therefore, the core task of this study is to integrate demand-side resources, as a competing solution against supply-side alternatives, with decentralized energy planning decisions and demonstrate the rewarding role it plays. Moreover, sustainability indicators (SIs are incorporated into DEP attempts in order to attain sustainable development. It is emphasized that unless these indicators are considered at lower energy planning levels, they will be ignored at higher planning levels as well. Hence, to the best knowledge of the authors, this study for the first time takes into account greenhouse gas (GHG emissions produced by utilization of renewable energies in DEP optimization models. To address the issues mentioned previously, multiobjective linear programming model along with a min-max goal programming approach is employed. Finally, using data taken from the literature, the model is solved, and the obtained results are discussed. The results show that DSM policies have remarkably contributed to significant improvements especially in terms of environmental indicators.

  10. Daily operation optimisation of hybrid stand-alone system by model predictive control considering ageing model

    International Nuclear Information System (INIS)

    Dufo-López, Rodolfo; Fernández-Jiménez, L. Alfredo; Ramírez-Rosado, Ignacio J.; Artal-Sevil, J. Sergio; Domínguez-Navarro, José A.; Bernal-Agustín, José L.

    2017-01-01

    Highlights: • Method for optimising the daily operation of photovoltaic-wind-diesel-battery systems. • Weather forecasts of hourly wind speed, irradiation, temperature and load are used. • Each day five control variables are optimised for the control of the system. • Operating cost includes real ageing of the batteries and the diesel generator. • Results show that the optimal control strategy used for each day led to cost savings. - Abstract: This article presents a method for optimising the daily operation (minimising the total operating cost) of a hybrid photovoltaic-wind-diesel-battery system using model predictive control. The model uses actual weather forecasts of hourly values of wind speed, irradiation, temperature and load. Five control variables are optimised, and thus their optimal set points values determine the optimal control strategy for each day. This involves the use of an accurate model for estimating the degradation of the batteries by considering the capacity loss due to corrosion and degradation. The model considers the extra costs of maintaining and replacing the diesel generator due to running out of its optimal conditions. The optimisation is carried out by means of genetic algorithms. An example of application compares the total operating cost obtained using the optimal control strategy for each day with the cost of using the optimal control strategy found for the whole year, obtaining savings of up to 7.8%. Also the comparison with the cost of using the “load following” control strategy is analysed, obtaining savings of up to 37.7%.

  11. The Importance of Business Model Factors for Cloud Computing Adoption: Role of Previous Experiences

    Directory of Open Access Journals (Sweden)

    Bogataj Habjan Kristina

    2017-08-01

    Full Text Available Background and Purpose: Bringing several opportunities for more effective and efficient IT governance and service exploitation, cloud computing is expected to impact the European and global economies significantly. Market data show that despite many advantages and promised benefits the adoption of cloud computing is not as fast and widespread as foreseen. This situation shows the need for further exploration of the potentials of cloud computing and its implementation on the market. The purpose of this research was to identify individual business model factors with the highest impact on cloud computing adoption. In addition, the aim was to identify the differences in opinion regarding the importance of business model factors on cloud computing adoption according to companies’ previous experiences with cloud computing services.

  12. Discovery of previously unrecognised local faults in London, UK, using detailed 3D geological modelling

    Science.gov (United States)

    Aldiss, Don; Haslam, Richard

    2013-04-01

    In parts of London, faulting introduces lateral heterogeneity to the local ground conditions, especially where construction works intercept the Palaeogene Lambeth Group. This brings difficulties to the compilation of a ground model that is fully consistent with the ground investigation data, and so to the design and construction of engineering works. However, because bedrock in the London area is rather uniform at outcrop, and is widely covered by Quaternary deposits, few faults are shown on the geological maps of the area. This paper discusses a successful resolution of this problem at a site in east central London, where tunnels for a new underground railway station are planned. A 3D geological model was used to provide an understanding of the local geological structure, in faulted Lambeth Group strata, that had not been possible by other commonly-used methods. This model includes seven previously unrecognised faults, with downthrows ranging from about 1 m to about 12 m. The model was constructed in the GSI3D geological modelling software using about 145 borehole records, including many legacy records, in an area of 850 m by 500 m. The basis of a GSI3D 3D geological model is a network of 2D cross-sections drawn by a geologist, generally connecting borehole positions (where the borehole records define the level of the geological units that are present), and outcrop and subcrop lines for those units (where shown by a geological map). When the lines tracing the base of each geological unit within the intersecting cross-sections are complete and mutually consistent, the software is used to generate TIN surfaces between those lines, so creating a 3D geological model. Even where a geological model is constructed as if no faults were present, changes in apparent dip between two data points within a single cross-section can indicate that a fault is present in that segment of the cross-section. If displacements of similar size with the same polarity are found in a series

  13. Modeling of PV Systems Based on Inflection Points Technique Considering Reverse Mode

    Directory of Open Access Journals (Sweden)

    Bonie J. Restrepo-Cuestas

    2013-11-01

    Full Text Available This paper proposes a methodology for photovoltaic (PV systems modeling, considering their behavior in both direct and reverse operating mode and considering mismatching conditions. The proposed methodology is based on the inflection points technique with a linear approximation to model the bypass diode and a simplified PV model. The proposed mathematical model allows to evaluate the energetic performance of a PV system, exhibiting short simulation times in large PV systems. In addition, this methodology allows to estimate the condition of the modules affected by the partial shading since it is possible to know the power dissipated due to its operation at the second quadrant.

  14. A fully coupled air foil bearing model considering friction – Theory & experiment

    DEFF Research Database (Denmark)

    von Osmanski, Alexander Sebastian; Larsen, Jon Steffen; Santos, Ilmar

    2017-01-01

    The dynamics of air foil bearings (AFBs) are not yet fully captured by any model. The recent years have, however, seen promising results from nonlinear time domain models, and simultaneously coupled formulations are now available, avoiding the previous requirements for undesirably small time steps...

  15. An improved car-following model considering variable safety headway distance

    Science.gov (United States)

    Jia, Yu-han; Du, Yi-man; Wu, Jian-ping

    2014-12-01

    Considering high speed following on expressway or highway, an improved car-following model is developed in this paper by introducing variable safety headway distance. Stability analysis of the new model is carried out using the control theory method. Finally, numerical simulations are implemented and the results show good consistency with theoretical study.

  16. Statistical Modeling of Ultrawideband Body-Centric Wireless Channels Considering Room Volume

    Directory of Open Access Journals (Sweden)

    Miyuki Hirose

    2012-01-01

    Full Text Available This paper presents the results of a statistical modeling of onbody ultrawideband (UWB radio channels for wireless body area network (WBAN applications. Measurements were conducted in five different rooms. A measured delay profile can be divided into two domains; in the first domain (04 ns has multipath components that are dominant and dependent on room volume. The first domain was modeled with a conventional power decay law model, and the second domain with a modified Saleh-Valenzuela model considering the room volume. Realizations of the impulse responses are presented based on the composite model and compared with the measured average power delay profiles.

  17. Driving-forces model on individual behavior in scenarios considering moving threat agents

    Science.gov (United States)

    Li, Shuying; Zhuang, Jun; Shen, Shifei; Wang, Jia

    2017-09-01

    The individual behavior model is a contributory factor to improve the accuracy of agent-based simulation in different scenarios. However, few studies have considered moving threat agents, which often occur in terrorist attacks caused by attackers with close-range weapons (e.g., sword, stick). At the same time, many existing behavior models lack validation from cases or experiments. This paper builds a new individual behavior model based on seven behavioral hypotheses. The driving-forces model is an extension of the classical social force model considering scenarios including moving threat agents. An experiment was conducted to validate the key components of the model. Then the model is compared with an advanced Elliptical Specification II social force model, by calculating the fitting errors between the simulated and experimental trajectories, and being applied to simulate a specific circumstance. Our results show that the driving-forces model reduced the fitting error by an average of 33.9% and the standard deviation by an average of 44.5%, which indicates the accuracy and stability of the model in the studied situation. The new driving-forces model could be used to simulate individual behavior when analyzing the risk of specific scenarios using agent-based simulation methods, such as risk analysis of close-range terrorist attacks in public places.

  18. Modelling and forecasting monthly and daily river discharge data using hybrid models and considering autoregressive heteroscedasticity

    Science.gov (United States)

    Szolgayova, Elena

    2010-05-01

    Hybrid modelling, used for simulation and forecasting of hydrological time series, involving both process-based and data-driven types of models combines the available domain knowledge and process physics with the recent advances in data driven tools. In this way, complex hydrological processes can be modelled and forecasted by decomposing the problem into several smaller sub - problems and using process physics based models where these are most appropriate, and data dictated tools (such as ANN, time series models or traditional statistics) for the residual data, when necessary. The fitting and forecasting performance of such models have to be explored case based. So far, only a few attempts to apply various nonlinear time series models within such a framework were reported in the hydrological modelling literature. This contribution presents results concerning the possibility to use GARCH type of models for such purposes. More specifically, error time series from two hydrological conceptual models were analyzed (applied on time series measured from the Hron and Morava Rivers in Slovakia), concentrating on the improvement of the modelling and forecasting performance of these models. The goal of investigation was to try to expand the knowledge in the time series modelling of hydrological model error time series with the aim to test and develop appropriate methods for various time steps from the GARCH family of models. In order to achieve this, following steps were taken: 1. The presence of heteroscedasticity was verified in time series. 2. A model from the GARCH family was fitted on the data, comparing the fit with a fit of an ARMA model. 3. One - step - ahead forecasts from the fitted models were produced, performing comparisons. The investigation of model properties and performances was thoroughly tested under various conditions of their future practical applications. In general, heteroscedasticity was present in the majority of the error time series of the

  19. Issues to be considered on obtaining plant models for formal verification purposes

    Science.gov (United States)

    Pacheco, R.; Gonzalez, L.; Intriago, M.; Machado, J.; Prisacaru, G.; Olaru, D.

    2016-08-01

    The development of dependable software for mechatronic systems can be a very complex and hard task. For facilitating the obtaining of dependable software for industrial controllers, some powerful software tools and analysis techniques can be used. Mainly, when using simulation and formal verification analysis techniques, it is necessary to develop plant models, in order to describe the plant behavior of those systems. However, developing a plant model implies that designer takes his (or her) decisions concerning granularity and level of abstraction of models; approach to consider for modeling (global or modular); and definition of strategies for simulation and formal verification tasks. This paper intends to highlight some aspects that can be considered for taking into account those decisions. For this purpose, it is presented a case study and there are illustrated and discussed very important aspects concerning above exposed issues.

  20. Hydration kinetics modeling of Portland cement considering the effects of curing temperature and applied pressure

    International Nuclear Information System (INIS)

    Lin Feng; Meyer, Christian

    2009-01-01

    A hydration kinetics model for Portland cement is formulated based on thermodynamics of multiphase porous media. The mechanism of cement hydration is discussed based on literature review. The model is then developed considering the effects of chemical composition and fineness of cement, water-cement ratio, curing temperature and applied pressure. The ultimate degree of hydration of Portland cement is also analyzed and a corresponding formula is established. The model is calibrated against the experimental data for eight different Portland cements. Simple relations between the model parameters and cement composition are obtained and used to predict hydration kinetics. The model is used to reproduce experimental results on hydration kinetics, adiabatic temperature rise, and chemical shrinkage of different cement pastes. The comparisons between the model reproductions and the different experimental results demonstrate the applicability of the proposed model, especially for cement hydration at elevated temperature and high pressure.

  1. Modeling abundance using N-mixture models: the importance of considering ecological mechanisms.

    Science.gov (United States)

    Joseph, Liana N; Elkin, Ché; Martin, Tara G; Possinghami, Hugh P

    2009-04-01

    Predicting abundance across a species' distribution is useful for studies of ecology and biodiversity management. Modeling of survey data in relation to environmental variables can be a powerful method for extrapolating abundances across a species' distribution and, consequently, calculating total abundances and ultimately trends. Research in this area has demonstrated that models of abundance are often unstable and produce spurious estimates, and until recently our ability to remove detection error limited the development of accurate models. The N-mixture model accounts for detection and abundance simultaneously and has been a significant advance in abundance modeling. Case studies that have tested these new models have demonstrated success for some species, but doubt remains over the appropriateness of standard N-mixture models for many species. Here we develop the N-mixture model to accommodate zero-inflated data, a common occurrence in ecology, by employing zero-inflated count models. To our knowledge, this is the first application of this method to modeling count data. We use four variants of the N-mixture model (Poisson, zero-inflated Poisson, negative binomial, and zero-inflated negative binomial) to model abundance, occupancy (zero-inflated models only) and detection probability of six birds in South Australia. We assess models by their statistical fit and the ecological realism of the parameter estimates. Specifically, we assess the statistical fit with AIC and assess the ecological realism by comparing the parameter estimates with expected values derived from literature, ecological theory, and expert opinion. We demonstrate that, despite being frequently ranked the "best model" according to AIC, the negative binomial variants of the N-mixture often produce ecologically unrealistic parameter estimates. The zero-inflated Poisson variant is preferable to the negative binomial variants of the N-mixture, as it models an ecological mechanism rather than a

  2. An Age-Hardening Model for Al-Mg-Si Alloys Considering Needle-Shaped Precipitates

    NARCIS (Netherlands)

    Bahrami, A.; Miroux, A.; Sietsma, J.

    2012-01-01

    In the present study, an age-hardening model for Al-Mg-Si alloys was developed considering cylindrical morphology with constant aspect ratio for precipitates. It is assumed that the precipitate distribution during underaging is controlled by simultaneous nucleation and growth, and after peak age,

  3. A semi-analytical bearing model considering outer race flexibility for model based bearing load monitoring

    Science.gov (United States)

    Kerst, Stijn; Shyrokau, Barys; Holweg, Edward

    2018-05-01

    This paper proposes a novel semi-analytical bearing model addressing flexibility of the bearing outer race structure. It furthermore presents the application of this model in a bearing load condition monitoring approach. The bearing model is developed as current computational low cost bearing models fail to provide an accurate description of the more and more common flexible size and weight optimized bearing designs due to their assumptions of rigidity. In the proposed bearing model raceway flexibility is described by the use of static deformation shapes. The excitation of the deformation shapes is calculated based on the modelled rolling element loads and a Fourier series based compliance approximation. The resulting model is computational low cost and provides an accurate description of the rolling element loads for flexible outer raceway structures. The latter is validated by a simulation-based comparison study with a well-established bearing simulation software tool. An experimental study finally shows the potential of the proposed model in a bearing load monitoring approach.

  4. Considering the Epistemic Uncertainties of the Variogram Model in Locating Additional Exploratory Drillholes

    Directory of Open Access Journals (Sweden)

    Saeed Soltani

    2015-06-01

    Full Text Available To enhance the certainty of the grade block model, it is necessary to increase the number of exploratory drillholes and collect more data from the deposit. The inputs of the process of locating these additional drillholes include the variogram model parameters, locations of the samples taken from the initial drillholes, and the geological block model. The uncertainties of these inputs will lead to uncertainties in the optimal locations of additional drillholes. Meanwhile, the locations of the initial data are crisp, but the variogram model parameters and the geological model have uncertainties due to the limitation of the number of initial data. In this paper, effort has been made to consider the effects of variogram uncertainties on the optimal location of additional drillholes using the fuzzy kriging and solve the locating problem with the genetic algorithm (GA optimization method.A bauxite deposit case study has shown the efficiency of the proposed model.

  5. A 3D finite strain phenomenological constitutive model for shape memory alloys considering martensite reorientation

    Science.gov (United States)

    Arghavani, J.; Auricchio, F.; Naghdabadi, R.; Reali, A.; Sohrabpour, S.

    2010-06-01

    Most devices based on shape memory alloys experience both finite deformations and non-proportional loading conditions in engineering applications. This motivates the development of constitutive models considering finite strain as well as martensite variant reorientation. To this end, in the present article, based on the principles of continuum thermodynamics with internal variables, a three-dimensional finite strain phenomenological constitutive model is proposed taking its basis from the recent model in the small strain regime proposed by Panico and Brinson (J Mech Phys Solids 55:2491-2511, 2007). In the finite strain constitutive model derivation, a multiplicative decomposition of the deformation gradient into elastic and inelastic parts, together with an additive decomposition of the inelastic strain rate tensor into transformation and reorientation parts is adopted. Moreover, it is shown that, when linearized, the proposed model reduces exactly to the original small strain model.

  6. A testing-coverage software reliability model considering fault removal efficiency and error generation.

    Science.gov (United States)

    Li, Qiuying; Pham, Hoang

    2017-01-01

    In this paper, we propose a software reliability model that considers not only error generation but also fault removal efficiency combined with testing coverage information based on a nonhomogeneous Poisson process (NHPP). During the past four decades, many software reliability growth models (SRGMs) based on NHPP have been proposed to estimate the software reliability measures, most of which have the same following agreements: 1) it is a common phenomenon that during the testing phase, the fault detection rate always changes; 2) as a result of imperfect debugging, fault removal has been related to a fault re-introduction rate. But there are few SRGMs in the literature that differentiate between fault detection and fault removal, i.e. they seldom consider the imperfect fault removal efficiency. But in practical software developing process, fault removal efficiency cannot always be perfect, i.e. the failures detected might not be removed completely and the original faults might still exist and new faults might be introduced meanwhile, which is referred to as imperfect debugging phenomenon. In this study, a model aiming to incorporate fault introduction rate, fault removal efficiency and testing coverage into software reliability evaluation is developed, using testing coverage to express the fault detection rate and using fault removal efficiency to consider the fault repair. We compare the performance of the proposed model with several existing NHPP SRGMs using three sets of real failure data based on five criteria. The results exhibit that the model can give a better fitting and predictive performance.

  7. An extended continuum model considering optimal velocity change with memory and numerical tests

    Science.gov (United States)

    Qingtao, Zhai; Hongxia, Ge; Rongjun, Cheng

    2018-01-01

    In this paper, an extended continuum model of traffic flow is proposed with the consideration of optimal velocity changes with memory. The new model's stability condition and KdV-Burgers equation considering the optimal velocities change with memory are deduced through linear stability theory and nonlinear analysis, respectively. Numerical simulation is carried out to study the extended continuum model, which explores how optimal velocity changes with memory affected velocity, density and energy consumption. Numerical results show that when considering the effects of optimal velocity changes with memory, the traffic jams can be suppressed efficiently. Both the memory step and sensitivity parameters of optimal velocity changes with memory will enhance the stability of traffic flow efficiently. Furthermore, numerical results demonstrates that the effect of optimal velocity changes with memory can avoid the disadvantage of historical information, which increases the stability of traffic flow on road, and so it improve the traffic flow stability and minimize cars' energy consumptions.

  8. An improved car-following model considering headway changes with memory

    Science.gov (United States)

    Yu, Shaowei; Shi, Zhongke

    2015-03-01

    To describe car-following behaviors in complex situations better, increase roadway traffic mobility and minimize cars' fuel consumptions, the linkage between headway changes with memory and car-following behaviors was explored with the field car-following data by using the gray correlation analysis method, and then an improved car-following model considering headway changes with memory on a single lane was proposed based on the full velocity difference model. Some numerical simulations were carried out by employing the improved car-following model to explore how headway changes with memory affected each car's velocity, acceleration, headway and fuel consumptions. The research results show that headway changes with memory have significant effects on car-following behaviors and fuel consumptions and that considering headway changes with memory in designing the adaptive cruise control strategy can improve the traffic flow stability and minimize cars' fuel consumptions.

  9. PWSCC Growth Assessment Model Considering Stress Triaxiality Factor for Primary Alloy 600 Components

    Directory of Open Access Journals (Sweden)

    Jong-Sung Kim

    2016-08-01

    Full Text Available We propose a primary water stress corrosion cracking (PWSCC initiation model of Alloy 600 that considers the stress triaxiality factor to apply to finite element analysis. We investigated the correlation between stress triaxiality effects and PWSCC growth behavior in cold-worked Alloy 600 stream generator tubes, and identified an additional stress triaxiality factor that can be added to Garud's PWSCC initiation model. By applying the proposed PWSCC initiation model considering the stress triaxiality factor, PWSCC growth simulations based on the macroscopic phenomenological damage mechanics approach were carried out on the PWSCC growth tests of various cold-worked Alloy 600 steam generator tubes and compact tension specimens. As a result, PWSCC growth behavior results from the finite element prediction are in good agreement with the experimental results.

  10. Shift scheduling model considering workload and worker’s preference for security department

    Science.gov (United States)

    Herawati, A.; Yuniartha, D. R.; Purnama, I. L. I.; Dewi, LT

    2018-04-01

    Security department operates for 24 hours and applies shift scheduling to organize its workers as well as in hotel industry. This research has been conducted to develop shift scheduling model considering the workers physical workload using rating of perceived exertion (RPE) Borg’s Scale and workers’ preference to accommodate schedule flexibility. The mathematic model is developed in integer linear programming and results optimal solution for simple problem. Resulting shift schedule of the developed model has equally distribution shift allocation among workers to balance the physical workload and give flexibility for workers in working hours arrangement.

  11. A multi-state model for wind farms considering operational outage probability

    DEFF Research Database (Denmark)

    Cheng, Lin; Liu, Manjun; Sun, Yuanzhang

    2013-01-01

    developed by considering the following factors: running time, operating environment, operating conditions, and wind speed fluctuations. A multi-state model for wind farms is also established. Numerical results illustrate that the proposed model can be well applied to power system reliability assessment...... power penetration levels. Therefore, a more comprehensive analysis toward WECS as well as an appropriate reliability assessment model are essential for maintaining the reliable operation of power systems. In this paper, the impact of wind turbine outage probability on system reliability is firstly...

  12. Considering too few alternatives: The mental model theory of extensional reasoning.

    Science.gov (United States)

    Chevalley, Thierry; Schaeken, Walter

    2016-01-01

    When solving a simple probabilistic problem, people tend to build an incomplete mental representation. We observe this pattern in responses to probabilistic problems over a set of premises using the conjunction, disjunction, and conditional propositional connectives. The mental model theory of extensional reasoning explains this bias towards underestimating the number of possibilities: In reckoning with different interpretations of the premises (logical rules, mental model theoretical, and, specific to conditional premises, conjunction and biconditional interpretation) the mental model theory accounts for the majority of observations. Different interpretations of a premise result in a build-up of mental models that are often incomplete. These mental models are processed using either an extensional strategy relying on proportions amongst models, or a conflict monitoring strategy. The consequence of considering too few possibilities is an erroneous probability estimate akin to that faced by decision makers who fail to generate and consider all alternatives, a characteristic of bounded rationality. We compare our results to the results published by Johnson-Laird, Legrenzi, Girotto, Legrenzi, and Caverni [Johnson-Laird, P., Legrenzi, P., Girotto, V., Legrenzi, M., & Caverni, J. (1999). Naive probability: A mental model theory of extensional reasoning. Psychological Review, 106, 62-88. doi: 10. 1037/0033-295X.106.1.62], and we observe lower performance levels than those in the original article.

  13. An Improved General Motor Car-Following Model considering the Lateral Impact

    Directory of Open Access Journals (Sweden)

    Pengfei Tao

    2015-02-01

    Full Text Available We improve the typical GM car-following model. In order to describe the impacts of the lateral offset between the vehicles in car-following state, this paper proposes time distance to measure the drivers' attention of driving environment and uses generalized expectation headway to describe the ideal driving state of the driver. Take the difference between the actual and expected headway as the important standard for driver to decide whether to speed up or slow down. Then take the drivers' attentions and the expected headway as the decision-making factors, and consider them while revising the GM car-following model. The numerical simulation shows the improved GM model conforms to the general driving behavior, enhances the function of the typical model, and strengthens the model stability.

  14. A development of multi-Species mass transport model considering thermodynamic phase equilibrium

    DEFF Research Database (Denmark)

    Hosokawa, Yoshifumi; Yamada, Kazuo; Johannesson, Björn

    2008-01-01

    ) variation in solid-phase composition when using different types of cement, (ii) physicochemical evaluation of steel corrosion initiation behaviour by calculating the molar ratio of chloride ion to hydroxide ion [Cl]/[OH] in pore solution, (iii) complicated changes of solid-phase composition caused......In this paper, a multi-species mass transport model, which can predict time dependent variation of pore solution and solid-phase composition due to the mass transport into the hardened cement paste, has been developed. Since most of the multi-species models established previously, based...

  15. Reentry blackout prediction for atmospheric reentry demonstrator mission considering uncertainty in chemical reaction rate model

    Science.gov (United States)

    Jung, Minseok; Kihara, Hisashi; Abe, Ken-ichi; Takahashi, Yusuke

    2018-01-01

    A numerical simulation model of plasma flows and electromagnetic waves around a vehicle was developed to predict a radio frequency blackout. Plasma flows in the shock layer and the wake region were calculated using a computational fluid dynamics technique with a three-dimensional model. A finite-catalytic wall condition known to affect plasma properties, such as the number density of electrons, was considered for accurate prediction. A parametric study was performed to investigate the effect of uncertainty in the chemical reaction rate model on evaluating a radio frequency blackout. The behavior of electromagnetic waves in plasma was investigated using a frequency-dependent finite-difference time-domain method. Numerical simulations of reentry blackout were performed for the Atmospheric Reentry Demonstrator mission at various altitudes. The plasma flows and the complex movement of electromagnetic waves around the Atmospheric Reentry Demonstrator vehicle were clarified. The predicted signal loss profile was then directly compared with the experimental flight data to validate the present models. The numerical results generally reproduced the trends over altitudes of the measured data. It is suggested that the present simulation model can be used to investigate the radio frequency blackout and signal loss of electromagnetic waves in the communication of a reentry vehicle. It was confirmed that high associative ionization reaction rates contribute to reducing the electron density in the wake region and radio frequency blackout. It is suggested that the accuracy of predicting the signal loss improved when considering the uncertainty in the chemical reaction model for associative ionizations.

  16. Modeling, Design and Analysis of a Electrodynamic Levitation System by Considering the Skin Effect

    Directory of Open Access Journals (Sweden)

    Mohammad Rajabi Sabadani

    2016-01-01

    Full Text Available In this paper, lift and drag forces of permanent-magnet electrodynamic suspension (PMEDS System have been studied by considering the skin effect. Electrodynamic suspension is based on repulsive force between two magnetic fields with the same polarity. In this research the electrodynamic suspension system consists of a moving permanent magnet block levitated over a flat conducting plate with 2 mm thickness. At first, the analytical model of the PMEDS is proposed. For this propose, permanent magnet poles are modeled by the current sheets. Then the eddy current is calculated on aluminum sheet by considering the skin effect. Finally, the lift and drag forces are calculated in difference speed. The 2D finite element method is utilized to investigate the effect of speed variations on the performance of PMEDS at two different airgap. Two-dimensional finite element model, the accuracy of proposed analytical model is validated. The results of the finite element method are compared with results obtained by analytical model. It shows the accuracy of the analytical model in the estimation of the lift and drag forces of an electrodynamic suspension system.

  17. From Business Model to System Architecture Considering Goals, Aspects and Quality Standards

    Directory of Open Access Journals (Sweden)

    Jean Carlos Guzmán

    2013-12-01

    Full Text Available At present business models have been converted into strategic assets for enterprise organizations. They facilitate information management for decisions making, transactions between parties and optimized services. The goal of this work is to present an Architectural Design Process (DAOMAC integrating Goals, Aspects and Quality Standards techniques and practices, to obtain an Initial Architecture for the software system from the business model. The main contribution of this work is to consider explicitly non-functional requirements in the different abstraction levels involved in the process to obtain the initial architecture model, and guaranteeing their traceability: tasks originating non-functional goals in the business model where they are not explicitly considered, non-functional crosscutting goals in the goal model, crosscutting concerns treated as softgoals and operationalizations in the SIG (Softgoal Interdependency Graph model. The main artifact obtained is the initial architecture and its logical view can be appreciated in the DAOMAC application to the case study, an administrative service process of the Citizen Identification and Registration System. Another important contribution is the specification of non-functional requirements by the ISO/IEC 25010 standard to facilitate their traceability and the communication among work groups.

  18. Modeling and dynamic simulation of astronaut's upper limb motions considering counter torques generated by the space suit.

    Science.gov (United States)

    Li, Jingwen; Ye, Qing; Ding, Li; Liao, Qianfang

    2017-07-01

    Extravehicular activity (EVA) is an inevitable task for astronauts to maintain proper functions of both the spacecraft and the space station. Both experimental research in a microgravity simulator (e.g. neutral buoyancy tank, zero-g aircraft or a drop tower/tube) and mathematical modeling were used to study EVA to provide guidance for the training on Earth and task design in space. Modeling has become more and more promising because of its efficiency. Based on the task analysis, almost 90% of EVA activity is accomplished through upper limb motions. Therefore, focusing on upper limb models of the body and space suit is valuable to this effort. In previous modeling studies, some multi-rigid-body systems were developed to simplify the human musculoskeletal system, and the space suit was mostly considered as a part of the astronaut body. With the aim to improve the reality of the models, we developed an astronauts' upper limb model, including a torque model and a muscle-force model, with the counter torques from the space suit being considered as a boundary condition. Inverse kinematics and the Maggi-Kane's method was applied to calculate the joint angles, joint torques and muscle force given that the terminal trajectory of upper limb motion was known. Also, we validated the muscle-force model using electromyogram (EMG) data collected in a validation experiment. Muscle force calculated from our model presented a similar trend with the EMG data, supporting the effectiveness and feasibility of the muscle-force model we established, and also, partially validating the joint model in kinematics aspect.

  19. Nonlinear analysis of an improved continuum model considering headway change with memory

    Science.gov (United States)

    Cheng, Rongjun; Wang, Jufeng; Ge, Hongxia; Li, Zhipeng

    2018-01-01

    Considering the effect of headway changes with memory, an improved continuum model of traffic flow is proposed in this paper. By means of linear stability theory, the new model’s linear stability with the effect of headway changes with memory is obtained. Through nonlinear analysis, the KdV-Burgers equation is derived to describe the propagating behavior of traffic density wave near the neutral stability line. Numerical simulation is carried out to study the improved traffic flow model, which explores how the headway changes with memory affected each car’s velocity, density and energy consumption. Numerical results show that when considering the effects of headway changes with memory, the traffic jams can be suppressed efficiently. Furthermore, research results demonstrate that the effect of headway changes with memory can avoid the disadvantage of historical information, which will improve the stability of traffic flow and minimize car energy consumption.

  20. Modelling Management Practices in Viticulture while Considering Resource Limitations: The Dhivine Model.

    Directory of Open Access Journals (Sweden)

    Roger Martin-Clouaire

    Full Text Available Many farming-system studies have investigated the design and evaluation of crop-management practices with respect to economic performance and reduction in environmental impacts. In contrast, little research has been devoted to analysing these practices in terms of matching the recurrent context-dependent demand for resources (labour in particular with those available on the farm. This paper presents Dhivine, a simulation model of operational management of grape production at the vineyard scale. Particular attention focuses on representing a flexible plan, which organises activities temporally, the resources available to the vineyard manager and the process of scheduling and executing the activities. The model relies on a generic production-system ontology used in several agricultural production domains. The types of investigations that the model supports are briefly illustrated. The enhanced realism of the production-management situations simulated makes it possible to examine and understand properties of resource-constrained work-organisation strategies and possibilities for improving them.

  1. A QFD-Based Mathematical Model for New Product Development Considering the Target Market Segment

    OpenAIRE

    Chen, Liang-Hsuan; Chen, Cheng-Nien

    2014-01-01

    Responding to customer needs is important for business success. Quality function deployment provides systematic procedures for converting customer needs into technical requirements to ensure maximum customer satisfaction. The existing literature mainly focuses on the achievement of maximum customer satisfaction under a budgetary limit via mathematical models. The market goal of the new product for the target market segment is usually ignored. In this study, the proposed approach thus consider...

  2. Research on spot power market equilibrium model considering the electric power network characteristics

    International Nuclear Information System (INIS)

    Wang, Chengmin; Jiang, Chuanwen; Chen, Qiming

    2007-01-01

    Equilibrium is the optimum operational condition for the power market by economics rule. A realistic spot power market cannot achieve the equilibrium condition due to network losses and congestions. The impact of the network losses and congestion on spot power market is analyzed in this paper in order to establish a new equilibrium model considering the network loss and transmission constraints. The OPF problem formulated according to the new equilibrium model is solved by means of the equal price principle. A case study on the IEEE-30-bus system is provided in order to prove the effectiveness of the proposed approach. (author)

  3. Improved dq-Axes Model of PMSM Considering Airgap Flux Harmonics and Saturation

    DEFF Research Database (Denmark)

    Fasil, Muhammed; Antaloae, Ciprian; Mijatovic, Nenad

    2016-01-01

    In this work, the classical linear model of a permanent magnet synchronous motor (PMSM) is modified by adding d and q-axes harmonic inductances so that the modified model can consider non-linearities present in an interior permanent magnet (IPM) motor. Further, a method has been presented to assess...... the effect of saturation and cross-saturation on constant torque curves of PMSM. Two IPM motors with two different rotor topologies and different specifications are designed to evaluate the effect of saturation on synchronous and harmonic inductances, and on operating points of the machines...

  4. Head flying characteristics in heat assisted magnetic recording considering various nanoscale heat transfer models

    Science.gov (United States)

    Hu, Yueqiang; Wu, Haoyu; Meng, Yonggang; Wang, Yu; Bogy, David

    2018-01-01

    The thermal issues in heat-assisted magnetic recording (HAMR) technology have drawn much attention in the recent literature. In this paper, the head flying characteristics and thermal performance of a HAMR system during the touch-down process considering different nanoscale heat transfer models across the head-disk interface are numerically studied. An optical-thermal-mechanical coupled model is first described. The coupling efficiency of the near field transducer is found to be dependent on the head disk clearance. The shortcomings of a constant disk-temperature model are investigated, which reveals the importance of considering the disk temperature as a variable. A study of the head flying on the disk is carried out using an air conduction model and additional near-field heat transfer models. It is shown that when the head disk interface is filled with a solid material caused by the laser-induced accumulation, the heat transfer coefficient can become unexpectedly large and the head's temperature can rise beyond desirable levels. Finally, the additional head protrusion due to the laser heating is investigated.

  5. Coupling model of aerobic waste degradation considering temperature, initial moisture content and air injection volume.

    Science.gov (United States)

    Ma, Jun; Liu, Lei; Ge, Sai; Xue, Qiang; Li, Jiangshan; Wan, Yong; Hui, Xinminnan

    2018-03-01

    A quantitative description of aerobic waste degradation is important in evaluating landfill waste stability and economic management. This research aimed to develop a coupling model to predict the degree of aerobic waste degradation. On the basis of the first-order kinetic equation and the law of conservation of mass, we first developed the coupling model of aerobic waste degradation that considered temperature, initial moisture content and air injection volume to simulate and predict the chemical oxygen demand in the leachate. Three different laboratory experiments on aerobic waste degradation were simulated to test the model applicability. Parameter sensitivity analyses were conducted to evaluate the reliability of parameters. The coupling model can simulate aerobic waste degradation, and the obtained simulation agreed with the corresponding results of the experiment. Comparison of the experiment and simulation demonstrated that the coupling model is a new approach to predict aerobic waste degradation and can be considered as the basis for selecting the economic air injection volume and appropriate management in the future.

  6. A model for phosphate glass topology considering the modifying ion sub-network

    DEFF Research Database (Denmark)

    Hermansen, Christian; Mauro, J.C.; Yue, Yuanzheng

    2014-01-01

    In the present paper we establish a temperature dependent constraint model of alkali phosphate glasses considering the structural and topological role of the modifying ion sub-network constituted by alkali ions and their non-bonding oxygen coordination spheres. The model is consistent with availa......In the present paper we establish a temperature dependent constraint model of alkali phosphate glasses considering the structural and topological role of the modifying ion sub-network constituted by alkali ions and their non-bonding oxygen coordination spheres. The model is consistent...... with available structural data by NMR and molecular dynamics simulation and dynamic data such glass transition temperature (Tg) and liquid fragility (m). Alkali phosphate glasses are exemplary systems for developing constraint model since the modifying cation network plays an important role besides the primary...... of the modifying ion sub-network, as the alkali ions must share non-bonding oxygen to satisfy their coordination requirements at higher alkali oxide contents. We argue that the systematically decreasing the Tg values of alkali phosphate glasses from Li2O to Na2O to Cs2O could be caused by a weakening...

  7. Dynamic 8-state ICSAR rumor propagation model considering official rumor refutation

    Science.gov (United States)

    Zhang, Nan; Huang, Hong; Su, Boni; Zhao, Jinlong; Zhang, Bo

    2014-12-01

    With the rapid development of information networks, negative impacts of rumor propagation become more serious. Nowadays, knowing the mechanisms of rumor propagation and having an efficient official rumor refutation plan play very important roles in reducing losses and ensuring social safety. In this paper we first develop the dynamic 8-state ICSAR (Ignorance, Information Carrier, Information Spreader, Information Advocate, Removal) rumor propagation model to study the mechanism of rumor propagation. Eight influencing factors including information attraction, objective identification of rumors, subjective identification of people, the degree of trust of information media, spread probability, reinforcement coefficient, block value and expert effects which are related to rumor propagation were analyzed. Next, considering these factors and mechanisms of rumor propagation and refutation, the dynamic 8-state ICSAR rumor propagation model is verified by the SIR epidemic model, computer simulation and actual data. Thirdly, through quantitative sensitivity analysis, the detailed function of each influencing factor was studied and shown in the figure directly. According to these mechanisms, we could understand how to block a rumor in a very efficient way and which methods should be chosen in different situations. The ICSAR model can divide people into 8 states and analyze rumor and anti-rumor dissemination in an accurate way. Furthermore, official rumor refutation is considered in rumor propagation. The models and the results are essential for improving the efficiency of rumor refutation and making emergency plans, which help to reduce the possibility of losses in disasters and rumor propagation.

  8. Optimization Scheduling Model for Wind-thermal Power System Considering the Dynamic penalty factor

    Science.gov (United States)

    PENG, Siyu; LUO, Jianchun; WANG, Yunyu; YANG, Jun; RAN, Hong; PENG, Xiaodong; HUANG, Ming; LIU, Wanyu

    2018-03-01

    In this paper, a new dynamic economic dispatch model for power system is presented.Objective function of the proposed model presents a major novelty in the dynamic economic dispatch including wind farm: introduced the “Dynamic penalty factor”, This factor could be computed by using fuzzy logic considering both the variable nature of active wind power and power demand, and it could change the wind curtailment cost according to the different state of the power system. Case studies were carried out on the IEEE30 system. Results show that the proposed optimization model could mitigate the wind curtailment and the total cost effectively, demonstrate the validity and effectiveness of the proposed model.

  9. Analytical model of cracking due to rebar corrosion expansion in concrete considering the structure internal force

    Directory of Open Access Journals (Sweden)

    Xiangyue Lin

    2017-12-01

    Full Text Available Based on the assumptions of uniform corrosion and linear elastic expansion, an analytical model of cracking due to rebar corrosion expansion in concrete was established, which is able to consider the structure internal force. And then, by means of the complex variable function theory and series expansion technology established by Muskhelishvili, the corresponding stress component functions of concrete around the reinforcement were obtained. Also, a comparative analysis was conducted between the numerical simulation model and present model in this paper. The results show that the calculation results of both methods were consistent with each other, and the numerical deviation was less than 10%, proving that the analytical model established in this paper is reliable.

  10. Thermal Impedance Model of High Power IGBT Modules Considering Heat Coupling Effects

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2014-01-01

    thermal models, only the self-heating effects of the chips are taken into account, while the thermal coupling effects among chips are less considered. This could result in inaccurate temperature estimation, especially in the high power IGBT modules where the chips are allocated closely to each other...... with large amount of heat generated. In this paper, both the self-heating and heat-coupling effects in the of IGBT module are investigated based on Finite Element Method (FEM) simulation, a new thermal impedance model is thereby proposed to better describe the temperature distribution inside IGBT modules....... It is concluded that the heat coupling between IGBT and diode chips strongly influence the temperature distribution inside IGBT module, and this effect can be properly modeled/predicted by the proposed thermal impedance model....

  11. Considering linear generator copper losses on model predictive control for a point absorber wave energy converter

    International Nuclear Information System (INIS)

    Montoya Andrade, Dan-El; Villa Jaén, Antonio de la; García Santana, Agustín

    2014-01-01

    Highlights: • We considered the linear generator copper losses in the proposed MPC strategy. • We maximized the power transferred to the generator side power converter. • The proposed MPC increases the useful average power injected into the grid. • The stress level of the PTO system can be reduced by the proposed MPC. - Abstract: The amount of energy that a wave energy converter can extract depends strongly on the control strategy applied to the power take-off system. It is well known that, ideally, the reactive control allows for maximum energy extraction from waves. However, the reactive control is intrinsically noncausal in practice and requires some kind of causal approach to be applied. Moreover, this strategy does not consider physical constraints and this could be a problem because the system could achieve unacceptable dynamic values. These, and other control techniques have focused on the wave energy extraction problem in order to maximize the energy absorbed by the power take-off device without considering the possible losses in intermediate devices. In this sense, a reactive control that considers the linear generator copper losses has been recently proposed to increase the useful power injected into the grid. Among the control techniques that have emerged recently, the model predictive control represents a promising strategy. This approach performs an optimization process on a time prediction horizon incorporating dynamic constraints associated with the physical features of the power take-off system. This paper proposes a model predictive control technique that considers the copper losses in the control optimization process of point absorbers with direct drive linear generators. This proposal makes the most of reactive control as it considers the copper losses, and it makes the most of the model predictive control, as it considers the system constraints. This means that the useful power transferred from the linear generator to the power

  12. New spatial clustering-based models for optimal urban facility location considering geographical obstacles

    Science.gov (United States)

    Javadi, Maryam; Shahrabi, Jamal

    2014-03-01

    The problems of facility location and the allocation of demand points to facilities are crucial research issues in spatial data analysis and urban planning. It is very important for an organization or governments to best locate its resources and facilities and efficiently manage resources to ensure that all demand points are covered and all the needs are met. Most of the recent studies, which focused on solving facility location problems by performing spatial clustering, have used the Euclidean distance between two points as the dissimilarity function. Natural obstacles, such as mountains and rivers, can have drastic impacts on the distance that needs to be traveled between two geographical locations. While calculating the distance between various supply chain entities (including facilities and demand points), it is necessary to take such obstacles into account to obtain better and more realistic results regarding location-allocation. In this article, new models were presented for location of urban facilities while considering geographical obstacles at the same time. In these models, three new distance functions were proposed. The first function was based on the analysis of shortest path in linear network, which was called SPD function. The other two functions, namely PD and P2D, were based on the algorithms that deal with robot geometry and route-based robot navigation in the presence of obstacles. The models were implemented in ArcGIS Desktop 9.2 software using the visual basic programming language. These models were evaluated using synthetic and real data sets. The overall performance was evaluated based on the sum of distance from demand points to their corresponding facilities. Because of the distance between the demand points and facilities becoming more realistic in the proposed functions, results indicated desired quality of the proposed models in terms of quality of allocating points to centers and logistic cost. Obtained results show promising

  13. Reactive Power Pricing Model Considering the Randomness of Wind Power Output

    Science.gov (United States)

    Dai, Zhong; Wu, Zhou

    2018-01-01

    With the increase of wind power capacity integrated into grid, the influence of the randomness of wind power output on the reactive power distribution of grid is gradually highlighted. Meanwhile, the power market reform puts forward higher requirements for reasonable pricing of reactive power service. Based on it, the article combined the optimal power flow model considering wind power randomness with integrated cost allocation method to price reactive power. Meanwhile, considering the advantages and disadvantages of the present cost allocation method and marginal cost pricing, an integrated cost allocation method based on optimal power flow tracing is proposed. The model realized the optimal power flow distribution of reactive power with the minimal integrated cost and wind power integration, under the premise of guaranteeing the balance of reactive power pricing. Finally, through the analysis of multi-scenario calculation examples and the stochastic simulation of wind power outputs, the article compared the results of the model pricing and the marginal cost pricing, which proved that the model is accurate and effective.

  14. A new stochastic model considering satellite clock interpolation errors in precise point positioning

    Science.gov (United States)

    Wang, Shengli; Yang, Fanlin; Gao, Wang; Yan, Lizi; Ge, Yulong

    2018-03-01

    Precise clock products are typically interpolated based on the sampling interval of the observational data when they are used for in precise point positioning. However, due to the occurrence of white noise in atomic clocks, a residual component of such noise will inevitable reside within the observations when clock errors are interpolated, and such noise will affect the resolution of the positioning results. In this paper, which is based on a twenty-one-week analysis of the atomic clock noise characteristics of numerous satellites, a new stochastic observation model that considers satellite clock interpolation errors is proposed. First, the systematic error of each satellite in the IGR clock product was extracted using a wavelet de-noising method to obtain the empirical characteristics of atomic clock noise within each clock product. Then, based on those empirical characteristics, a stochastic observation model was structured that considered the satellite clock interpolation errors. Subsequently, the IGR and IGS clock products at different time intervals were used for experimental validation. A verification using 179 stations worldwide from the IGS showed that, compared with the conventional model, the convergence times using the stochastic model proposed in this study were respectively shortened by 4.8% and 4.0% when the IGR and IGS 300-s-interval clock products were used and by 19.1% and 19.4% when the 900-s-interval clock products were used. Furthermore, the disturbances during the initial phase of the calculation were also effectively improved.

  15. Impedance Characterization and Modeling of Lithium-Ion Batteries Considering the Internal Temperature Gradient

    Directory of Open Access Journals (Sweden)

    Haifeng Dai

    2018-01-01

    Full Text Available Battery impedance is essential to the management of lithium-ion batteries for electric vehicles (EVs, and impedance characterization can help to monitor and predict the battery states. Many studies have been undertaken to investigate impedance characterization and the factors that influence impedance. However, few studies regarding the influence of the internal temperature gradient, which is caused by heat generation during operation, have been presented. We have comprehensively studied the influence of the internal temperature gradient on impedance characterization and the modeling of battery impedance, and have proposed a discretization model to capture battery impedance characterization considering the temperature gradient. Several experiments, including experiments with artificial temperature gradients, are designed and implemented to study the influence of the internal temperature gradient on battery impedance. Based on the experimental results, the parameters of the non-linear impedance model are obtained, and the relationship between the parameters and temperature is further established. The experimental results show that the temperature gradient will influence battery impedance and the temperature distribution can be considered to be approximately linear. The verification results indicate that the proposed discretization model has a good performance and can be used to describe the actual characterization of the battery with an internal temperature gradient.

  16. New battery model considering thermal transport and partial charge stationary effects in photovoltaic off-grid applications

    Science.gov (United States)

    Sanz-Gorrachategui, Iván; Bernal, Carlos; Oyarbide, Estanis; Garayalde, Erik; Aizpuru, Iosu; Canales, Jose María; Bono-Nuez, Antonio

    2018-02-01

    The optimization of the battery pack in an off-grid Photovoltaic application must consider the minimum sizing that assures the availability of the system under the worst environmental conditions. Thus, it is necessary to predict the evolution of the state of charge of the battery under incomplete daily charging and discharging processes and fluctuating temperatures over day-night cycles. Much of previous development work has been carried out in order to model the short term evolution of battery variables. Many works focus on the on-line parameter estimation of available charge, using standard or advanced estimators, but they are not focused on the development of a model with predictive capabilities. Moreover, normally stable environmental conditions and standard charge-discharge patterns are considered. As the actual cycle-patterns differ from the manufacturer's tests, batteries fail to perform as expected. This paper proposes a novel methodology to model these issues, with predictive capabilities to estimate the remaining charge in a battery after several solar cycles. A new non-linear state space model is proposed as a basis, and the methodology to feed and train the model is introduced. The new methodology is validated using experimental data, providing only 5% of error at higher temperatures than the nominal one.

  17. Considering built environment and spatial correlation in modelling pedestrian injury severity

    DEFF Research Database (Denmark)

    Prato, Carlo G.; Kaplan, Sigal; Patrier, Alexandre

    traffic calming measures, illumination solutions, road maintenance programs and speed limit reductions. Moreover, this study emphasises the role of the built environment, as shopping areas, residential areas, and walking traffic density are positively related to a reduction in pedestrian injury severity......This study looks at mitigating and aggravating factors that are associated with the injury severity of pedestrians when they have crashes with another road user and overcomes existing limitations in the literature by posing attention on the built environment and considering spatial correlation...... of pedestrians to sustain a severe or fatal injury conditional on the occurrence of a crash with another road user. This study confirms previous findings about older pedestrians and intoxicated pedestrians being the most vulnerable road users, and crashes with heavy vehicles and in roads with higher speed limits...

  18. Considering built environment and spatial correlation in modelling pedestrian injury severity

    DEFF Research Database (Denmark)

    Prato, Carlo G.; Kaplan, Sigal; Patrier, Alexandre

    2018-01-01

    traffic calming measures, illumination solutions, road maintenance programs and speed limit reductions. Moreover, this study emphasises the role of the built environment, as shopping areas, residential areas, and walking traffic density are positively related to a reduction in pedestrian injury severity......This study looks at mitigating and aggravating factors that are associated with the injury severity of pedestrians when they have crashes with another road user and overcomes existing limitations in the literature by posing attention on the built environment and considering spatial correlation...... of pedestrians to sustain a severe or fatal injury conditional on the occurrence of a crash with another road user. This study confirms previous findings about older pedestrians and intoxicated pedestrians being the most vulnerable road users, and crashes with heavy vehicles and in roads with higher speed limits...

  19. Third metacarpal condylar fatigue fractures in equine athletes occur within previously modelled subchondral bone.

    Science.gov (United States)

    Whitton, R Christopher; Trope, Gareth D; Ghasem-Zadeh, Ali; Anderson, Garry A; Parkin, Timothy D H; Mackie, Eleanor J; Seeman, Ego

    2010-10-01

    Bone modelling and remodelling reduce the risk of fatigue fractures; the former by adapting bone to its loading circumstances, the latter by replacing fatigued bone. Remodelling transiently increases porosity because of the normal delay in onset of the formation phase of the remodelling sequence. Protracted intense loading suppresses remodelling leaving modelling as the only means of maintaining bone strength. We therefore hypothesized that race horses with fatigue fractures of the distal third metacarpal bone (MC3) will have reduced porosity associated with suppressed remodelling while continued adaptive modelling will result in higher volume fraction (BV/TV) at this site. Using high resolution peripheral quantitative computed tomography (HR-pQCT), we measured the distal aspect of the MC3 obtained at postmortem from 13 thoroughbred race horses with condylar fractures of the MC3 (cases), 8 horses without fractures (training controls), 14 horses with a fracture at another site (fractured controls) and 9 horses resting from training (resting controls). Porosity of the subchondral bone of MC3 was lower in cases than resting controls (12±1.4% vs. 18±1.6%, P=0.017) although areas of focal porosity were observed adjacent to fractures in 6/13 horses. BV/TV of the distal metacarpal epiphysis tended to be higher in horses with condylar fractures (0.79±0.015) than training controls (0.74±0.019, P=0.070), but also higher in controls with a fracture elsewhere (0.79±0.014) than the training controls (0.74±0.019, P=0.040). BV/TV was higher in horses over three years of age than those aged two or three years (0.79±0.01 vs. 0.74±0.01, P=0.016). All metacarpal condylar fractures occurred within focal areas of high BV/TV. We infer that intense training in equine athletes suppresses remodelling of third metacarpal subchondral bone limiting damage repair while modelling increases regional bone volume in an attempt to minimise local stresses but may fail to offset bone

  20. A cellular automata traffic flow model considering the heterogeneity of acceleration and delay probability

    Science.gov (United States)

    Li, Qi-Lang; Wong, S. C.; Min, Jie; Tian, Shuo; Wang, Bing-Hong

    2016-08-01

    This study examines the cellular automata traffic flow model, which considers the heterogeneity of vehicle acceleration and the delay probability of vehicles. Computer simulations are used to identify three typical phases in the model: free-flow, synchronized flow, and wide moving traffic jam. In the synchronized flow region of the fundamental diagram, the low and high velocity vehicles compete with each other and play an important role in the evolution of the system. The analysis shows that there are two types of bistable phases. However, in the original Nagel and Schreckenberg cellular automata traffic model, there are only two kinds of traffic conditions, namely, free-flow and traffic jams. The synchronized flow phase and bistable phase have not been found.

  1. A mathematical model in cellular manufacturing system considering subcontracting approach under constraints

    Directory of Open Access Journals (Sweden)

    Kamran Forghani

    2012-10-01

    Full Text Available In this paper, a new mathematical model in cellular manufacturing systems (CMSs has been presented. In order to increase the performance of manufacturing system, the production quantity of parts has been considered as a decision variable, i.e. each part can be produced and outsourced, simultaneously. This extension would be minimized the unused capacity of machines. The exceptional elements (EEs are taken into account and would be totally outsourced to the external supplier in order to remove intercellular material handling cost. The problem has been formulated as a mixed-integer programming to minimize the sum of manufacturing variable costs under budget, machines capacity and demand constraints. Also, to evaluate advantages of the model, several illustrative numerical examples have been provided to compare the performance of the proposed model with the available classical approaches in the literature.

  2. A Study on an Analysis Model of Grounding Electrode for Power Distribution Lines Considering Transient Behavior

    Science.gov (United States)

    Hirai, Takao; Miyazaki, Teru; Okabe, Shigemitsu; Aiba, Kiyoshi; Yoshinaga, Jun

    Lightning performance of grounding electrode is one of the most important lightning-protection features of power distribution lines. It is well known that ground resistance has current-dependent characteristic due to soil ionization. Moreover, it also has time-dependent characteristic. But especially transient behavior has not been represented by EMTP models well because its mechanism is not cleared. In order to clarify the transient behaviors of the grounding electrode, experiments were conducted with full-scale grounding systems. In this study, the paper describes a grounding electrode model that can be easily used in the EMTP analysis. The proposed model considers both current-dependent and time-dependent characteristics. It is verified by comparing calculated results with the experimental results.

  3. A Cellular Automata Traffic Flow Model considering Bus Lane Changing Behavior with Scheduling Parameters

    Directory of Open Access Journals (Sweden)

    Zun-dong Zhang

    2015-01-01

    Full Text Available According to different driving behavioral characteristics of bus drivers, a cellular automata traffic model considering the bus lane changing behavior with scheduling parameters is proposed in this paper. Traffic bottleneck problems caused by bus stops are simulated in multiple lanes roads with no-bay bus stations. With the mixed traffic flow composed of different bus arrival rate, flow-density graph, density distribution graph, and temporal-spatial graph are presented. Furthermore, the mixed traffic flow characteristics are analyzed. Numerical experiment results show that the proposed model can generate a variety of complicated realistic phenomena in the traffic system with bus stops and provide theoretical basis for better using of traffic flow model.

  4. Polarized heavy baryon production in quark-diquark model considering two different scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Moosavi Nejad, S.M. [Yazd University, Faculty of Physics, Yazd (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, Tehran (Iran, Islamic Republic of); Delpasand, M. [Yazd University, Faculty of Physics, Yazd (Iran, Islamic Republic of)

    2017-09-15

    At sufficiently large transverse momentum, the dominant production mechanism for heavy baryons is actually the fragmentation. In this work, we first study the direct fragmentation of a heavy quark into the unpolarized triply heavy baryons in the leading order of perturbative QCD. In a completely different approach, we also analyze the two-stage fragmentation of a heavy quark into a scalar diquark followed by the fragmentation of such a scalar diquark into a triply heavy baryon: quark-diquark model of baryons. The results of this model are in acceptable agreement with those obtained through a full perturbative regime. Relying on the quark-diquark model and considering two different scenarios we determine the spin-dependent fragmentation functions of polarized heavy baryons in such a way that a vector or a pseudoscalar heavy diquark is an intermediate particle between the initial heavy quark and the final state baryon. (orig.)

  5. Cost allocation model for distribution networks considering high penetration of distributed energy resources

    DEFF Research Database (Denmark)

    Soares, Tiago; Pereira, Fábio; Morais, Hugo

    2015-01-01

    The high penetration of distributed energy resources (DER) in distribution networks and the competitive environment of electricity markets impose the use of new approaches in several domains. The network cost allocation, traditionally used in transmission networks, should be adapted and used...... in the distribution networks considering the specifications of the connected resources. The main goal is to develop a fairer methodology trying to distribute the distribution network use costs to all players which are using the network in each period. In this paper, a model considering different type of costs (fixed......, losses, and congestion costs) is proposed comprising the use of a large set of DER, namely distributed generation (DG), demand response (DR) of direct load control type, energy storage systems (ESS), and electric vehicles with capability of discharging energy to the network, which is known as vehicle...

  6. Experimental and Computational Modal Analyses for Launch Vehicle Models considering Liquid Propellant and Flange Joints

    Directory of Open Access Journals (Sweden)

    Chang-Hoon Sim

    2018-01-01

    Full Text Available In this research, modal tests and analyses are performed for a simplified and scaled first-stage model of a space launch vehicle using liquid propellant. This study aims to establish finite element modeling techniques for computational modal analyses by considering the liquid propellant and flange joints of launch vehicles. The modal tests measure the natural frequencies and mode shapes in the first and second lateral bending modes. As the liquid filling ratio increases, the measured frequencies decrease. In addition, as the number of flange joints increases, the measured natural frequencies increase. Computational modal analyses using the finite element method are conducted. The liquid is modeled by the virtual mass method, and the flange joints are modeled using one-dimensional spring elements along with the node-to-node connection. Comparison of the modal test results and predicted natural frequencies shows good or moderate agreement. The correlation between the modal tests and analyses establishes finite element modeling techniques for modeling the liquid propellant and flange joints of space launch vehicles.

  7. Testing and Micromechanical Modelling of Rockfill Materials Considering the Effect of Stress Path

    Directory of Open Access Journals (Sweden)

    Wang Feng

    2016-01-01

    Full Text Available We have extended the micromechanics-based analytical (M-A model to make it capable of simulating Nuozhadu rockfill material (NRFM under different stress paths. Two types of drained triaxial tests on NRFM were conducted, namely, the stress paths of constant stress ratio (CSR and the complex stress paths with transitional features. The model was improved by considering the interparticle parameter variation with the unloading-reloading cycles and the effect of the stress transition path. The evolution of local dilatancy at interparticle planes due to an externally applied load is also discussed. Compared with Duncan-Chang’s E-u and E-B models, the improved model could not only better describe the deformation properties of NRFM under the stress path loading, but also present the volumetric strain changing from dilatancy to contractancy with increasing transitional confining pressures. All simulations have demonstrated that the proposed M-A model is capable of modelling the mechanical behaviour of NRFM in the dam.

  8. A Generic Friction Model for Radial Slider Bearing Simulation Considering Elastic and Plastic Deformation

    Directory of Open Access Journals (Sweden)

    Günter Offner

    2015-06-01

    Full Text Available The investigation of component dynamics is one of the main tasks of internal combustion engine (ICE simulation. This prediction is important in order to understand complex loading conditions, which happen in a running ICE. Due to the need for fuel saving, mechanical friction, in particular in radial slider bearings, is one important investigation target. A generic friction modeling approach for radial slider bearings, which can be applied to lubricated contact regimes, will be presented in this paper. Besides viscous friction, the approach considers in particular boundary friction. The parameterization of the friction model is done using surface material and surface roughness measurement data. Furthermore, fluid properties depending on the applied oil additives are being considered. The application of the model will be demonstrated for a typical engineering task of a connecting rod big end study to outline the effects of contact surface texture. AlSn-based and polymer coated bearing shells will be analyzed and compared with respect to friction reduction effects, running-in behavior and thermal load capabilities.

  9. Modelization of a large wind farm, considering the modification of the atmospheric boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Crespo, A.; Gomez-Elvira, R. [Univ. Politecnica de Madrid, Mecanica de Fluidos, E.T.S.I. Industriales, Madrid (Spain); Frandsen, S.; Larsen, S.E. [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    A method is presented to adapt existing models of wind farms to very large ones that may affect the whole planetary boundary layer. An internal boundary layer is considered that starts developing at the leading edge of the farm until it reaches, sufficiently far downstream, the top of the planetary boundary layer, and a new equilibrium region is reached. The wind farm is simulated by an artificial roughness that is function of the turbine spacing, drag and height. From this model the flow conditions are calculated at a certain reference height and then are used as boundary conditions for a numerical code used to model a wind farm. Three-dimensional effects are considered by applying appropriate conditions at the sides of the farm. Calculations are carried out to estimate the energy production in large wind farms, and it is found that additional losses due to modification of the planetary boundary layer may be of importance for wind farms of size larger than about 100 km. (au)

  10. A Modelling Study for Predicting Life of Downhole Tubes Considering Service Environmental Parameters and Stress

    Directory of Open Access Journals (Sweden)

    Tianliang Zhao

    2016-09-01

    Full Text Available A modelling effort was made to try to predict the life of downhole tubes or casings, synthetically considering the effect of service influencing factors on corrosion rate. Based on the discussed corrosion mechanism and corrosion processes of downhole tubes, a mathematic model was established. For downhole tubes, the influencing factors are environmental parameters and stress, which vary with service duration. Stress and the environmental parameters including water content, partial pressure of H2S and CO2, pH value, total pressure and temperature, were considered to be time-dependent. Based on the model, life-span of an L80 downhole tube in oilfield Halfaya, an oilfield in Iraq, was predicted. The results show that life-span of the L80 downhole tube in Halfaya is 247 months (approximately 20 years under initial stress of 0.1 yield strength and 641 months (approximately 53 years under no initial stress, which indicates that an initial stress of 0.1 yield strength will reduce the life-span by more than half.

  11. A Modelling Study for Predicting Life of Downhole Tubes Considering Service Environmental Parameters and Stress

    Science.gov (United States)

    Zhao, Tianliang; Liu, Zhiyong; Du, Cuiwei; Hu, Jianpeng; Li, Xiaogang

    2016-01-01

    A modelling effort was made to try to predict the life of downhole tubes or casings, synthetically considering the effect of service influencing factors on corrosion rate. Based on the discussed corrosion mechanism and corrosion processes of downhole tubes, a mathematic model was established. For downhole tubes, the influencing factors are environmental parameters and stress, which vary with service duration. Stress and the environmental parameters including water content, partial pressure of H2S and CO2, pH value, total pressure and temperature, were considered to be time-dependent. Based on the model, life-span of an L80 downhole tube in oilfield Halfaya, an oilfield in Iraq, was predicted. The results show that life-span of the L80 downhole tube in Halfaya is 247 months (approximately 20 years) under initial stress of 0.1 yield strength and 641 months (approximately 53 years) under no initial stress, which indicates that an initial stress of 0.1 yield strength will reduce the life-span by more than half. PMID:28773872

  12. Equivalent Modeling of DFIG-Based Wind Power Plant Considering Crowbar Protection

    Directory of Open Access Journals (Sweden)

    Qianlong Zhu

    2016-01-01

    Full Text Available Crowbar conduction has an impact on the transient characteristics of a doubly fed induction generator (DFIG in the short-circuit fault condition. But crowbar protection is seldom considered in the aggregation method for equivalent modeling of DFIG-based wind power plants (WPPs. In this paper, the relationship between the growth of postfault rotor current and the amplitude of the terminal voltage dip is studied by analyzing the rotor current characteristics of a DFIG during the fault process. Then, a terminal voltage dip criterion which can identify crowbar conduction is proposed. Considering the different grid connection structures for single DFIG and WPP, the criterion is revised and the crowbar conduction is judged depending on the revised criterion. Furthermore, an aggregation model of the WPP is established based on the division principle of crowbar conduction. Finally, the proposed equivalent WPP is simulated on a DIgSILENT PowerFactory platform and the results are compared with those of the traditional equivalent WPPs and the detailed WPP. The simulation results show the effectiveness of the method for equivalent modeling of DFIG-based WPP when crowbar protection is also taken into account.

  13. Deterioration modeling for condition assessment of flexible pavements considering extreme weather events

    Science.gov (United States)

    Hashemi Tari, Yasamin; Shahini Shamsabadi, Salar; Birken, Ralf; Wang, Ming

    2015-04-01

    Accurate pavement management systems are essential for states' Department Of Transportation and roadway agencies to plan for cost-effective maintenance and repair (M and R) strategies. Pavement deterioration model is an imperative component of any pavement management system since the future budget and M and R plans would be developed based on the predicted pavement performance measures. It is crucial for the pavement deterioration models to consider the factors that significantly aggravate the pavement condition. While many studies have highlighted the impact of different environmental, load, and pavement's structure on the life cycle of the pavement, effect of extreme weather events such as Floods and Snow Storms have often been overlooked. In this study, a pavement deterioration model is proposed which would consider the effect of traffic loads, climate conditions, and extreme weather events. Climate, load and performance data has been compiled for over twenty years and for eight states using the Long Term Pavement Performance (LTPP) and National Oceanic and Atmospheric Administration (NOAA) databases. A stepwise regression approach is undertaken to quantify the effect of the extreme weather events, along with other influential factors on pavement performance in terms of International Roughness Index (IRI). Final results rendered more than 90% correlation with the quantified impact values of extreme weather events.

  14. Integrate System Modeling for Design and Production Planning of High Quality Products Considering Failure Data

    Science.gov (United States)

    Aoyama, Kazuhiro; Koga, Tsuyoshi

    2009-07-01

    Since the product recall problem is recently observed, realizing design and production activities that can prevent occurrences of a product failure has been becoming a serious issue. This paper proposes "the Synthetic design approach of a product and a production process which enables to reduce occurrences of a product failure from the initial stage of a product development." In order to realize this proposed concept as a specific system, the integrated model of the failure information in the design and production is introduced. This paper shows some examples of design and production for a circuit breaker and an automobile with considering a design error and a production failure using developed prototype system.

  15. Effects of previous severe exercise on two and three parameter critical power modeling

    Directory of Open Access Journals (Sweden)

    Eduardo Kokubun

    2007-09-01

    Full Text Available The purpose of this study was to apply the two and three-parameter critical power model equations after depletion of a fi xed amount of anaerobic work capacity (AWC, followed by a short rest period. Sixteen subjects underwent: (1 two practice trials for ergometer familiarization to severe exercise; (2 4-5 exercise bouts on different days for the estimation of critical power (CP and AWC using the two and three parameter models; (3 the same procedures as described in stage 2 were repeated after 30 s recovery from 180 s of exercise completed at an intensity that would have elicited exhaustion in around 300 s. The CP2parameter (130-174 W versus 131-170 W and CP3parameter (108 versus 100 W estimated after prior severe exercise followed by a short rest period remained stable compared to the fatigue-free tests. The AWC2parameter was reduced in response to prior severe exercise. The AWC3parameter was not significantly reduced. The correlations between CP2parameter derived from the same equation with and without prior AWC2parameter reduction were strong (r = 0.97-0.99, P ABSTRACT O propósito do presente estudo foi aplicar as equações do modelo de potência crítica de dois e três parâmetros após a depleção de uma quantia fi xa de capacidade de trabalho anaeróbio (AWC, seguido de um período curto de repouso. Dezesseis sujeitos realizaram: (1 duas familiarizações ao exercício severo no cicloergômetro; (2 4-5 exercícios máximos em dias diferentes para a estimativa da CP e AWC por meio dos modelos de dois e três parâmetros; (3 os mesmos procedimentos descritos no #2 foram realizados após 30 s de repouso e de um exercício de 180 s a uma intensidade em que a exaustão provavelmente ocorreria em ~300 s. A CP2parameter (130-174 W versus 131-170 W e CP3parameter (108 versus 100 W estimadas após o exercício prévio severo e seguido por um curto período de repouso permaneceu estável quando comparado às estimativas sem o exercício pr

  16. Liver growth factor treatment reverses emphysema previously established in a cigarette smoke exposure mouse model.

    Science.gov (United States)

    Pérez-Rial, Sandra; Del Puerto-Nevado, Laura; Girón-Martínez, Alvaro; Terrón-Expósito, Raúl; Díaz-Gil, Juan J; González-Mangado, Nicolás; Peces-Barba, Germán

    2014-11-01

    Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease largely associated with cigarette smoke exposure (CSE) and characterized by pulmonary and extrapulmonary manifestations, including systemic inflammation. Liver growth factor (LGF) is an albumin-bilirubin complex with demonstrated antifibrotic, antioxidant, and antihypertensive actions even at extrahepatic sites. We aimed to determine whether short LGF treatment (1.7 μg/mouse ip; 2 times, 2 wk), once the lung damage was established through the chronic CSE, contributes to improvement of the regeneration of damaged lung tissue, reducing systemic inflammation. We studied AKR/J mice, divided into three groups: control (air-exposed), CSE (chronic CSE), and CSE + LGF (LGF-treated CSE mice). We assessed pulmonary function, morphometric data, and levels of various systemic inflammatory markers to test the LGF regenerative capacity in this system. Our results revealed that the lungs of the CSE animals showed pulmonary emphysema and inflammation, characterized by increased lung compliance, enlargement of alveolar airspaces, systemic inflammation (circulating leukocytes and serum TNF-α level), and in vivo lung matrix metalloproteinase activity. LGF treatment was able to reverse all these parameters, decreasing total cell count in bronchoalveolar lavage fluid and T-lymphocyte infiltration in peripheral blood observed in emphysematous mice and reversing the decrease in monocytes observed in chronic CSE mice, and tends to reduce the neutrophil population and serum TNF-α level. In conclusion, LGF treatment normalizes the physiological and morphological parameters and levels of various systemic inflammatory biomarkers in a chronic CSE AKR/J model, which may have important pathophysiological and therapeutic implications for subjects with stable COPD. Copyright © 2014 the American Physiological Society.

  17. Planar rigid-flexible coupling spacecraft modeling and control considering solar array deployment and joint clearance

    Science.gov (United States)

    Li, Yuanyuan; Wang, Zilu; Wang, Cong; Huang, Wenhu

    2018-01-01

    Based on Nodal Coordinate Formulation (NCF) and Absolute Nodal Coordinate Formulation (ANCF), this paper establishes rigid-flexible coupling dynamic model of the spacecraft with large deployable solar arrays and multiple clearance joints to analyze and control the satellite attitude under deployment disturbance. Considering torque spring, close cable loop (CCL) configuration and latch mechanisms, a typical spacecraft composed of a rigid main-body described by NCF and two flexible panels described by ANCF is used as a demonstration case. Nonlinear contact force model and modified Coulomb friction model are selected to establish normal contact force and tangential friction model, respectively. Generalized elastic force are derived and all generalized forces are defined in the NCF-ANCF frame. The Newmark-β method is used to solve system equations of motion. The availability and superiority of the proposed model is verified through comparing with numerical co-simulations of Patran and ADAMS software. The numerical results reveal the effects of panel flexibility, joint clearance and their coupling on satellite attitude. The effects of clearance number, clearance size and clearance stiffness on satellite attitude are investigated. Furthermore, a proportional-differential (PD) attitude controller of spacecraft is designed to discuss the effect of attitude control on the dynamic responses of the whole system.

  18. Model for Assembly Line Re-Balancing Considering Additional Capacity and Outsourcing to Face Demand Fluctuations

    Science.gov (United States)

    Samadhi, TMAA; Sumihartati, Atin

    2016-02-01

    The most critical stage in a garment industry is sewing process, because generally, it consists of a number of operations and a large number of sewing machines for each operation. Therefore, it requires a balancing method that can assign task to work station with balance workloads. Many studies on assembly line balancing assume a new assembly line, but in reality, due to demand fluctuation and demand increased a re-balancing is needed. To cope with those fluctuating demand changes, additional capacity can be carried out by investing in spare sewing machine and paying for sewing service through outsourcing. This study develops an assembly line balancing (ALB) model on existing line to cope with fluctuating demand change. Capacity redesign is decided if the fluctuation demand exceeds the available capacity through a combination of making investment on new machines and outsourcing while considering for minimizing the cost of idle capacity in the future. The objective of the model is to minimize the total cost of the line assembly that consists of operating costs, machine cost, adding capacity cost, losses cost due to idle capacity and outsourcing costs. The model develop is based on an integer programming model. The model is tested for a set of data of one year demand with the existing number of sewing machines of 41 units. The result shows that additional maximum capacity up to 76 units of machine required when there is an increase of 60% of the average demand, at the equal cost parameters..

  19. An Euler-Lagrange method considering bubble radial dynamics for modeling sonochemical reactors.

    Science.gov (United States)

    Jamshidi, Rashid; Brenner, Gunther

    2014-01-01

    Unsteady numerical computations are performed to investigate the flow field, wave propagation and the structure of bubbles in sonochemical reactors. The turbulent flow field is simulated using a two-equation Reynolds-Averaged Navier-Stokes (RANS) model. The distribution of the acoustic pressure is solved based on the Helmholtz equation using a finite volume method (FVM). The radial dynamics of a single bubble are considered by applying the Keller-Miksis equation to consider the compressibility of the liquid to the first order of acoustical Mach number. To investigate the structure of bubbles, a one-way coupling Euler-Lagrange approach is used to simulate the bulk medium and the bubbles as the dispersed phase. Drag, gravity, buoyancy, added mass, volume change and first Bjerknes forces are considered and their orders of magnitude are compared. To verify the implemented numerical algorithms, results for one- and two-dimensional simplified test cases are compared with analytical solutions. The results show good agreement with experimental results for the relationship between the acoustic pressure amplitude and the volume fraction of the bubbles. The two-dimensional axi-symmetric results are in good agreement with experimentally observed structure of bubbles close to sonotrode. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Stability analysis of a new lattice hydrodynamic model by considering lattice's self-anticipative density effect

    Science.gov (United States)

    Zhang, Geng; Sun, Di-Hua; Liu, Hui; Chen, Dong

    2017-11-01

    In this paper, a new lattice hydrodynamic model with consideration of the density difference of a lattice's current density and its anticipative density is proposed. The influence of lattice's self-anticipative density on traffic stability is revealed through linear stability theory and it shows that lattice's self-anticipative density can improve the stability of traffic flow. To describe the phase transition of traffic flow, the mKdV equation near the critical point is derived by using nonlinear analysis method. The propagating behavior of density wave in the unstable region can be described by the kink-antikink soliton of the mKdV equation. Numerical simulation validates the analytical results, which shows that traffic jam can be suppressed efficiently by considering lattice's self-anticipative density in the modified lattice hydrodynamic model.

  1. A constitutive model of porous SMAs considering tensile-compressive asymmetry behaviors.

    Science.gov (United States)

    Liu, Bingfei; Dui, Guansuo; Xie, Benming; Xue, Lijun

    2014-04-01

    A constitutive model of the macroscopic behaviors of porous shape memory alloys (SMA) is developed in this work. A yield function for porous SMAs considering both the effect of hydrostatic stress and the tensile-compressive asymmetry is proposed. Combining the constitutive model of dense SMAs and the macroscale and microscale analysis, the evolution equation for the overall transformation strain is then derived. Examples for the response of both dense SMA and porous Ni-Ti SMA subjected to uniaxial tension and compression loads are supplied. Good agreement between the numerical prediction results and the published experimental data is observed. Numerical result shows that the yielding stresses, loop width and length, strain-hardening behaviors of porous SMAs under pure tensile and pure compressive are different. Importantly, the transformation initiation stress is much closer to the experiment result than simulated by Zhao et al. (2005). Copyright © 2014. Published by Elsevier Ltd.

  2. SIR rumor spreading model considering the effect of difference in nodes’ identification capabilities

    Science.gov (United States)

    Wang, Ya-Qi; Wang, Jing

    In this paper, we study the effect of difference in network nodes’ identification capabilities on rumor propagation. A novel susceptible-infected-removed (SIR) model is proposed, based on the mean-field theory, to investigate the dynamical behaviors of such model on homogeneous networks and inhomogeneous networks, respectively. Theoretical analysis and simulation results demonstrate that when we consider the influence of difference in nodes’ identification capabilities, the critical thresholds obviously increase, but the final rumor sizes are apparently reduced. We also find that the difference in nodes’ identification capabilities prolongs the time of rumor propagation reaching a steady state, and decreases the number of nodes that finally accept rumors. Additionally, under the influence of difference of nodes’ identification capabilities, compared with the homogeneous networks, the rumor transmission rate on the inhomogeneous networks is relatively large.

  3. A QFD-Based Mathematical Model for New Product Development Considering the Target Market Segment

    Directory of Open Access Journals (Sweden)

    Liang-Hsuan Chen

    2014-01-01

    Full Text Available Responding to customer needs is important for business success. Quality function deployment provides systematic procedures for converting customer needs into technical requirements to ensure maximum customer satisfaction. The existing literature mainly focuses on the achievement of maximum customer satisfaction under a budgetary limit via mathematical models. The market goal of the new product for the target market segment is usually ignored. In this study, the proposed approach thus considers the target customer satisfaction degree for the target market segment in the model by formulating the overall customer satisfaction as a function of the quality level. In addition, the proposed approach emphasizes the cost-effectiveness concept in the design stage via the achievement of the target customer satisfaction degree using the minimal total cost. A numerical example is used to demonstrate the applicability of the proposed approach and its characteristics are discussed.

  4. Multi-Objective Demand Response Model Considering the Probabilistic Characteristic of Price Elastic Load

    Directory of Open Access Journals (Sweden)

    Shengchun Yang

    2016-01-01

    Full Text Available Demand response (DR programs provide an effective approach for dealing with the challenge of wind power output fluctuations. Given that uncertain DR, such as price elastic load (PEL, plays an important role, the uncertainty of demand response behavior must be studied. In this paper, a multi-objective stochastic optimization problem of PEL is proposed on the basis of the analysis of the relationship between price elasticity and probabilistic characteristic, which is about stochastic demand models for consumer loads. The analysis aims to improve the capability of accommodating wind output uncertainty. In our approach, the relationship between the amount of demand response and interaction efficiency is developed by actively participating in power grid interaction. The probabilistic representation and uncertainty range of the PEL demand response amount are formulated differently compared with those of previous research. Based on the aforementioned findings, a stochastic optimization model with the combined uncertainties from the wind power output and the demand response scenario is proposed. The proposed model analyzes the demand response behavior of PEL by maximizing the electricity consumption satisfaction and interaction benefit satisfaction of PEL. Finally, a case simulation on the provincial power grid with a 151-bus system verifies the effectiveness and feasibility of the proposed mechanism and models.

  5. Modeling Microbial Dynamics in Aquifers Considering the Interaction Between the Higher Trophic Levels

    Science.gov (United States)

    Bajracharya, B. M.; Cirpka, O. A.; Lu, C.

    2014-12-01

    Models of microbial dynamics coupled to solute transport in aquifers typically require the introduction of a bacterial carrying capacity term to prevent excessive microbial growth close to substrate-injection boundaries. The factors controlling this carrying capacity, however, are not fully understood. Most explanations for the occurrence of a carrying capacity discussed are based on the assumption of a bottom-up control of groundwater ecosystems. An alternative explanation is based on top-down control. Our model considers substrate, bacteria and higher trophic levels, such as grazers or bacteriophages. The dissolved substrate is transported with water flow whereas the biomasses of bacteria and grazers are considered essentially immobile. The one-dimensional reactive transport model also accounts for substrate dispersion and a random walk of grazers influenced by the bacteria concentration. The grazers grow on the bacteria, leading to a negative feedback on the bacteria concentration which may limit the turnover of the substrate. A single retentostat model with Monod kinetics of bacterial growth and a second-order grazing shows that the system oscillates but approaches a stable steady state with non-zero concentrations of substrate, bacteria, and grazers. The steady-state concentration of the bacteria biomass is independent of the substrate concentration in the inflow. When coupling several retentostats in a series to mimic a groundwater column, the steady-state bacteria concentrations remain at a constant level over a significant travel distance. The results show that grazing is a possible explanation of the carrying capacity, provided that there is enough substrate to sustain bacteria and grazers.

  6. Uncertainty Analysis of the Water Scarcity Footprint Based on the AWARE Model Considering Temporal Variations

    Directory of Open Access Journals (Sweden)

    Jong Seok Lee

    2018-03-01

    Full Text Available The purpose of this paper is to compare the degree of uncertainty of the water scarcity footprint using the Monte Carlo statistical method and block bootstrap method. Using the hydrological data of a water drainage basin in Korea, characterization factors based on the available water remaining (AWARE model were obtained. The uncertainties of the water scarcity footprint considering temporal variations in paddy rice production in Korea were estimated. The block bootstrap method gave five-times smaller percentage uncertainty values of the model output compared to that of the two different Monte Carlo statistical method scenarios. Incorrect estimation of the probability distribution of the AWARE characterization factor model is what causes the higher uncertainty in the water scarcity footprint value calculated by the Monte Carlo statistical method in this study. This is because AWARE characterization factor values partly follows discrete distribution with extreme value on one side. Therefore, this study suggests that the block bootstrap method is a better choice in analyzing uncertainty compared to the Monte Carlo statistical method when using the AWARE model to quantify the water scarcity footprint.

  7. Hydrodynamic and hydrostatic modelling of hydraulic journal bearings considering small displacement condition

    Science.gov (United States)

    Chen, Chi-Yin; Chuang, Jen-Chen; Tu, Jia-Ying

    2016-09-01

    This paper proposes modified coefficients for the dynamic model of hydraulic journal bearing system that integrates the hydrodynamic and hydrostatic properties. In recent years, design of hydraulic bearing for machine tool attracts worldwide attention, because hydraulic bearings are able to provide higher capacity and accuracy with lower friction, compared to conventional bearing systems. In order to achieve active control of the flow pressure and enhance the operation accuracy, the dynamic model of hydraulic bearings need to be developed. Modified coefficients of hydrostatic stiffness, hydrodynamic stiffness, and squeeze damping of the dynamic model are presented in this work, which are derived referring to small displacement analysis from literature. The proposed modified coefficients and model, which consider the pressure variations, relevant geometry size, and fluid properties of the journal bearings, are able to characterise the hydrodynamic and hydrostatic properties with better precision, thus offering the following pragmatic contribution: (1) on-line prediction of the eccentricity and the position of the shaft in the face of external force that results in vibration; (2) development of active control system to regulate the supply flow pressure and to minimize the eccentricity of the shaft. Theoretical derivation and simulation results with different vibration cases are discussed to verify the proposed techniques.

  8. A stress driven growth model for soft tissue considering biological availability

    International Nuclear Information System (INIS)

    Oller, S; Bellomo, F J; Nallim, L G; Armero, F

    2010-01-01

    Some of the key factors that regulate growth and remodeling of tissues are fundamentally mechanical. However, it is important to take into account the role of bioavailability together with the stresses and strains in the processes of normal or pathological growth. In this sense, the model presented in this work is oriented to describe the growth of soft biological tissue under 'stress driven growth' and depending on the biological availability of the organism. The general theoretical framework is given by a kinematic formulation in large strain combined with the thermodynamic basis of open systems. The formulation uses a multiplicative decomposition of deformation gradient, splitting it in a growth part and visco-elastic part. The strains due to growth are incompatible and are controlled by an unbalanced stresses related to a homeostatic state. Growth implies a volume change with an increase of mass maintaining constant the density. One of the most interesting features of the proposed model is the generation of new tissue taking into account the contribution of mass to the system controlled through biological availability. Because soft biological tissues in general have a hierarchical structure with several components (usually a soft matrix reinforced with collagen fibers), the developed growth model is suitable for the characterization of the growth of each component. This allows considering a different behavior for each of them in the context of a generalized theory of mixtures. Finally, we illustrate the response of the model in case of growth and atrophy with an application example.

  9. Capacitated set-covering model considering the distance objective and dependency of alternative facilities

    Science.gov (United States)

    Wayan Suletra, I.; Priyandari, Yusuf; Jauhari, Wakhid A.

    2018-03-01

    We propose a new model of facility location to solve a kind of problem that belong to a class of set-covering problem using an integer programming formulation. Our model contains a single objective function, but it represents two goals. The first is to minimize the number of facilities, and the other is to minimize the total distance of customers to facilities. The first goal is a mandatory goal, and the second is an improvement goal that is very useful when alternate optimum solutions for the first goal exist. We use a big number as a weight on the first goal to force the solution algorithm to give first priority to the first goal. Besides considering capacity constraints, our model accommodates a kind of either-or constraints representing facilities dependency. The either-or constraints will prevent the solution algorithm to select two or more facilities from the same set of facility with mutually exclusive properties. A real location selection problem to locate a set of wastewater treatment facility (IPAL) in Surakarta city, Indonesia, will describe the implementation of our model. A numerical example is given using the data of that real problem.

  10. Stochastic Production Frontier Models to Explore Constraints on Household Travel Expenditures Considering Household Income Classes

    Directory of Open Access Journals (Sweden)

    Sofyan M. Saleh

    2016-04-01

    Full Text Available This paper explores the variation of household travel expenditure frontiers (HTEFs prior to CC reform in Jakarta. This study incorporates the variation of household income classes into the modeling of HTEFs and investigates the degree to which various determinants influence levels of HTEF. The HTEF is defined as an unseen maximum (capacity amount of money that a certain income class is willing to dedicate to their travel. A stochastic production frontier is applied to model and explore upper bound household travel expenditure (HTE. Using a comprehensive household travel survey (HTS in Jakarta in 2004, the observed HTE spending in a month is treated as an exogenous variable. The estimation results obtained using three proposed models, for low, medium and high income classes, show that HTEFs are significantly associated with life stage structure attributes, socio-demographics and life environment factors such as professional activity engagements, which is disclosed to be varied across income classes. Finding further reveals that considerable differences in average of HTEFs across models. This finding calls for the formulation of policies that consider the needs to be addressed for low and medium income groups in order to promote more equity policy thereby leading to more acceptable CC reform.

  11. Modeling vehicle interior noise exposure dose on freeways: Considering weaving segment designs and engine operation.

    Science.gov (United States)

    Li, Qing; Qiao, Fengxiang; Yu, Lei; Shi, Junqing

    2017-07-05

    Vehicle interior noise functions at the dominant frequencies of 500 Hz below and around 800 Hz, which fall into the bands that may impair hearing. Recent studies demonstrated that freeway commuters are chronically exposed to vehicle interior noise, bearing the risk of hearing impairment. The interior noise evaluation process is mostly conducted in a laboratory environment. The test results and the developed noise models may underestimate or ignore the noise effects from dynamic traffic and road conditions and configuration. However, the interior noise is highly associated with vehicle maneuvering. The vehicle maneuvering on a freeway weaving segment is more complex because of its nature of conflicting areas. This research is intended to explore the risk of the interior noise exposure on freeway weaving segments for freeway commuters and to improve the interior noise estimation by constructing a decision tree learning-based noise exposure dose (NED) model, considering weaving segment designs and engine operation. On-road driving tests were conducted on 12 subjects on State Highway 288 in Houston, Texas. On-board Diagnosis (OBD) II, a smartphone-based roughness app, and a digital sound meter were used to collect vehicle maneuvering and engine information, International Roughness Index, and interior noise levels, respectively. Eleven variables were obtainable from the driving tests, including the length and type of a weaving segment, serving as predictors. The importance of the predictors was estimated by their out-of-bag-permuted predictor delta errors. The hazardous exposure level of the interior noise on weaving segments was quantified to hazard quotient, NED, and daily noise exposure level, respectively. Results showed that the risk of hearing impairment on freeway is acceptable; the interior noise level is the most sensitive to the pavement roughness and is subject to freeway configuration and traffic conditions. The constructed NED model shows high predictive

  12. Mathematical Modeling of Radiant Heat Transfer in Mirror Systems Considering Deep Reflecting Surface Defects

    Directory of Open Access Journals (Sweden)

    V. V. Leonov

    2014-01-01

    Full Text Available When designing large-sized mirror concentrating systems (MCS for high-temperature solar power plants, one must have at disposal reasonably reliable and economical methods and tools, making it possible to analyze its characteristics, to predict them depending on the operation conditions and accordingly to choose the most suitable system for the solution of particular task.Experimental determination of MCS characteristics requires complicated and expensive experimentation, having significant limitations on interpretation of the results, as well as limitations imposed due to the size of the structure. Therefore it is of particular interest to develop a mathematical model capable of estimating power characteristics of MCS considering the influence of operating conditions, design features, roughness and other surface defects.For efficient solution of the tasks the model must ensure simulation of solar radiant flux as well as simulation of geometrical and optical characteristics of reflection surface and their interaction. In this connection a statistical mathematical model of radiation heat exchange based on use of Monte Carlo methods and Finite Element Method was developed and realized in the software complex, making it possible to determine main characteristics of the MCS.In this paper the main attention is given to definition of MCS radiation characteristics with account for deep reflecting surface defects (cavities, craters. Deep cavities are not typical for MCS, but their occurrence is possible during operation as a result of erosion or any physical damage. For example, for space technology it is primarily micrometeorite erosion.

  13. Metro passengers’ route choice model and its application considering perceived transfer threshold

    Science.gov (United States)

    Jin, Fanglei; Zhang, Yongsheng; Liu, Shasha

    2017-01-01

    With the rapid development of the Metro network in China, the greatly increased route alternatives make passengers’ route choice behavior and passenger flow assignment more complicated, which presents challenges to the operation management. In this paper, a path sized logit model is adopted to analyze passengers’ route choice preferences considering such parameters as in-vehicle time, number of transfers, and transfer time. Moreover, the “perceived transfer threshold” is defined and included in the utility function to reflect the penalty difference caused by transfer time on passengers’ perceived utility under various numbers of transfers. Next, based on the revealed preference data collected in the Guangzhou Metro, the proposed model is calibrated. The appropriate perceived transfer threshold value and the route choice preferences are analyzed. Finally, the model is applied to a personalized route planning case to demonstrate the engineering practicability of route choice behavior analysis. The results show that the introduction of the perceived transfer threshold is helpful to improve the model’s explanatory abilities. In addition, personalized route planning based on route choice preferences can meet passengers’ diversified travel demands. PMID:28957376

  14. Choosing a Model for eConsult Specialist Remuneration: Factors to Consider

    Directory of Open Access Journals (Sweden)

    Clare Liddy

    2016-06-01

    Full Text Available Electronic consultation (eConsult is an innovative solution that allows specialists and primary care providers to communicate electronically, improving access to specialist care. Understanding the cost implications of different remuneration models available to pay specialists is of critical importance as adoption of these services continues to increase. We used data collected through the Champlain BASE (Building Access to Specialists through eConsultation eConsult service to simulate the cost implications of different remuneration models in Canada. The prorated hourly rate model averaged $45.72 CAD (Canadian Dollar per eConsult while the prorated hourly rate with incentive averaged $51.90 CAD per eConsult, and the fee for service cost $60.50 CAD per eConsult. Paying all specialty groups to block three hours per week for eConsults averaged $337.44 CAD per eConsult and paying for 1-h blocks averaged $133.41 CAD per eConsult. As the remuneration of specialists is the largest cost driver of an established eConsult service, our findings can inform policymakers considering the implementation of eConsult or wishing to further develop an existing service.

  15. An Order Insertion Scheduling Model of Logistics Service Supply Chain Considering Capacity and Time Factors

    Directory of Open Access Journals (Sweden)

    Weihua Liu

    2014-01-01

    Full Text Available Order insertion often occurs in the scheduling process of logistics service supply chain (LSSC, which disturbs normal time scheduling especially in the environment of mass customization logistics service. This study analyses order similarity coefficient and order insertion operation process and then establishes an order insertion scheduling model of LSSC with service capacity and time factors considered. This model aims to minimize the average unit volume operation cost of logistics service integrator and maximize the average satisfaction degree of functional logistics service providers. In order to verify the viability and effectiveness of our model, a specific example is numerically analyzed. Some interesting conclusions are obtained. First, along with the increase of completion time delay coefficient permitted by customers, the possible inserting order volume first increases and then trends to be stable. Second, supply chain performance reaches the best when the volume of inserting order is equal to the surplus volume of the normal operation capacity in mass service process. Third, the larger the normal operation capacity in mass service process is, the bigger the possible inserting order’s volume will be. Moreover, compared to increasing the completion time delay coefficient, improving the normal operation capacity of mass service process is more useful.

  16. Development of Regression Models considering Time-Lag and Aerosols for Predicting Heating Loads in Buildings

    Directory of Open Access Journals (Sweden)

    Hong Soo Lim

    2018-01-01

    Full Text Available Building automation systems is becoming more vital, especially in regard to reduced building energy consumption. However, the accuracy of such systems in calculating building thermal loads is limited as they are unable to predict future thermal loads based on prevailing environmental factors. The current paper therefore seeks to improve the understanding of the interactions between outdoor meteorological data and building energy consumption through a statistical analysis. Using weather data collected by the Korean Meteorological Agency (KMA over a period of three years (2011–2014, prediction models that are able to predict heating thermal loads considering the time-lag phenomenon are developed. In addition, the study develops different prediction models for buildings of different sizes. The results confirm the existence of the time-lag phenomenon: the heating load experienced by a building at a given time is better explained by a regression model developed using the climatic conditions that existed two hours before. As such, conventional building simulation programs must endeavor to include time-lag as well as Aerosol Optical Depth (AOD data as important factors in the prediction of building heating loads.

  17. Development of Deflection Prediction Model for Concrete Block Pavement Considering the Block Shapes and Construction Patterns

    Directory of Open Access Journals (Sweden)

    Wuguang Lin

    2016-01-01

    Full Text Available Concrete block pavement (CBP is distinct from typical concrete or asphalt pavements. It is built by using individual blocks with unique construction patterns forming a discrete surface layer to bear traffic loadings. The surface structure of CBP varies depending on the block shapes and construction patterns, so it is hard to apply a general equivalent elastic modulus estimation method to define the surface structural strength. In this study, FEM analysis and dynamic loading test were carried out to develop a deflection prediction model for CBP considering the block shapes and construction patterns. Based on the analysis results, it was found that block shapes did not have much effect on load distribution, whereas construction patterns did. By applying the deflection prediction model to the rutting model for CBP proposed by Sun, the herringbone bond pattern showed the best performance comparing with stretcher bond or basket weave bond pattern. As the load repetition increased to 1.2 million, the rutting depth of CBP constructed by herringbone bond pattern was 2 mm smaller than those constructed by the other two patterns.

  18. An order insertion scheduling model of logistics service supply chain considering capacity and time factors.

    Science.gov (United States)

    Liu, Weihua; Yang, Yi; Wang, Shuqing; Liu, Yang

    2014-01-01

    Order insertion often occurs in the scheduling process of logistics service supply chain (LSSC), which disturbs normal time scheduling especially in the environment of mass customization logistics service. This study analyses order similarity coefficient and order insertion operation process and then establishes an order insertion scheduling model of LSSC with service capacity and time factors considered. This model aims to minimize the average unit volume operation cost of logistics service integrator and maximize the average satisfaction degree of functional logistics service providers. In order to verify the viability and effectiveness of our model, a specific example is numerically analyzed. Some interesting conclusions are obtained. First, along with the increase of completion time delay coefficient permitted by customers, the possible inserting order volume first increases and then trends to be stable. Second, supply chain performance reaches the best when the volume of inserting order is equal to the surplus volume of the normal operation capacity in mass service process. Third, the larger the normal operation capacity in mass service process is, the bigger the possible inserting order's volume will be. Moreover, compared to increasing the completion time delay coefficient, improving the normal operation capacity of mass service process is more useful.

  19. Competition with Online and Offline Demands considering Logistics Costs Based on the Hotelling Model

    Directory of Open Access Journals (Sweden)

    Zhi-Hua Hu

    2014-01-01

    Full Text Available Through popular information technologies (e.g., call centers, web portal, ecommerce and social media, etc., traditional shops change their functions for servicing online demands while still providing offline sales and services, which expand the market and the service capacity. In the Hotelling model that formulates the demand effect by considering just offline demand, the shops in a line city will locate at the center as a the result of competition by games. The online demands are met by the delivery logistics services provided by the shops with additional cost; the consumers’ waiting time after their orders also affects their choices for shops. The main purpose is to study the effects of the following aspects on the shops’ location competition: two logistics costs (consumers’ travelling cost for offline demands and the shops’ delivery logistics cost for online demands, the consumers’ waiting cost for online orders, and the ratios of online demands to the whole demands. Therefore, this study primarily contributes to the literature on the formulation of these aspects by extending the Hotelling model. These features and effects are demonstrated by experiments using the extended Hotelling models.

  20. A New Method to Solving AR Model Parameters Considering Random Errors of Design Matrix

    Directory of Open Access Journals (Sweden)

    YAO Yibin

    2017-11-01

    Full Text Available The ordinary least square method could not solve the problem that the error exist both in design matrix and observation vector while compute parameter values of AR model. In this article, a new method is proposed which consider the random errors of design matrix. The source of design matrix and observation vector is same and the amount of parameters contain error can be equal by introducing virtual observation. Then, this problem could be solved under the framework of normal least square by equivalence transformation of observation equation. The result of this new method is superior to SVD method and normal least square method by simulation date and observation data which verify the feasibility and effectiveness of this method.

  1. Deployable wing model considering structural flexibility and aerodynamic unsteadiness for deployment system design

    Science.gov (United States)

    Otsuka, Keisuke; Wang, Yinan; Makihara, Kanjuro

    2017-11-01

    In future, wings will be deployed in the span direction during flight. The deployment system improves flight ability and saves storage space in the airplane. For the safe design of the wing, the deployment motion needs to be simulated. In the simulation, the structural flexibility and aerodynamic unsteadiness should be considered because they may lead to undesirable phenomena such as a residual vibration after the deployment or a flutter during the deployment. In this study, the deployment motion is simulated in the time domain by using a nonlinear folding wing model based on multibody dynamics, absolute nodal coordinate formulation, and two-dimensional aerodynamics with strip theory. We investigate the effect of the structural flexibility and aerodynamic unsteadiness on the time-domain deployment simulation.

  2. Development of repository-wide radionuclide transport model considering the effects of multiple sources

    International Nuclear Information System (INIS)

    Hatanaka, Koichiro; Watari, Shingo; Ijiri, Yuji

    1999-11-01

    Safety assessment of the geological isolation system according to the groundwater scenario has traditionally been conducted based on the signal canister configuration and then the safety of total system has been evaluated based on the dose rates which were obtained by multiplying the migration rates released from the engineered barrier and/or the natural barrier by dose conversion factors and total number of canisters disposed in the repository. The dose conversion factors can be obtained from the biosphere analysis. In this study, we focused on the effect of multiple sources due to the disposal of canisters at different positions in the repository. By taking the effect of multiple sources into consideration, concentration interference in the repository region is possible to take place. Therefore, radionuclide transport model/code considering the effect of concentration interference due to the multiple sources was developed to make assessments of the effect quantitatively. The newly developed model/code was verified through the comparison analysis with the existing radionuclide transport analysis code used in the second progress report. In addition, the effect of the concentration interference was evaluated by setting a simple problem using the newly developed analysis code. This results shows that the maximum park value of the migration rates from the repository was about two orders of magnitude lower than that based on single canister configuration. Since the analysis code was developed by assuming that all canisters disposed of along the one-dimensional groundwater flow contribute to the concentration interference in the repository region, the assumption should be verified by conducting two or three-dimensional analysis considering heterogeneous geological structure as a future work. (author)

  3. Closed-Loop Supply Chain Models with Considering the Environmental Impact

    Science.gov (United States)

    Fallah, Mohammad

    2014-01-01

    Global warming and climate changes created by large scale emissions of greenhouse gases are a worldwide concern. Due to this, the issue of green supply chain management has received more attention in the last decade. In this study, a closed-loop logistic concept which serves the purposes of recycling, reuse, and recovery required in a green supply chain is applied to integrate the environmental issues into a traditional logistic system. Here, we formulate a comprehensive closed-loop model for the logistics planning considering profitability and ecological goals. In this way, we can achieve the ecological goal reducing the overall amount of CO2 emitted from journeys. Moreover, the profitability criterion can be supported in the cyclic network with the minimum costs and maximum service level. We apply three scenarios and develop problem formulations for each scenario corresponding to the specified regulations and investigate the effect of the regulation on the preferred transport mode and the emissions. To validate the models, some numerical experiments are worked out and a comparative analysis is investigated. PMID:25309960

  4. Review of the model of technological pragmatism considering privacy and security

    Directory of Open Access Journals (Sweden)

    Kovačević-Lepojević Marina M.

    2013-01-01

    Full Text Available The model of technological pragmatism assumes awareness that technological development involves both benefits and dangers. Most modern security technologies represent citizens' mass surveillance tools, which can lead to compromising a significant amount of personal data due to the lack of institutional monitoring and control. On the other hand, people are interested in improving crime control and reducing the fear of potential victimization which this framework provides as a rational justification for the apparent loss of privacy, personal rights and freedoms. Citizens' perception on the categories of security and privacy, and their balancing, can provide the necessary guidelines to regulate the application of security technologies in the actual context. The aim of this paper is to analyze the attitudes of students at the University of Belgrade (N = 269 toward the application of security technology and identification of the key dimensions. On the basis of the relevant research the authors have formed assumptions about the following dimensions: security, privacy, trust in institutions and concern about the misuse of security technology. The Prise Questionnaire on Security Technology and Privacy was used for data collection. Factor analysis abstracted eight factors which together account for 58% of variance, with the highest loading of the four factors that are identified as security, privacy, trust and concern. The authors propose a model of technological pragmatism considering security and privacy. The data also showed that students are willing to change their privacy for the purpose of improving security and vice versa.

  5. Modeling and Simulation on Errors of Feed Unit by Considering Change of Force Bearing Point

    Directory of Open Access Journals (Sweden)

    Zhang Wei

    2017-01-01

    Full Text Available The linear feed unit is a type of precision linear motion component that is widely used in computer numerical control (CNC machine tools. The contact stiffness and error influences the performance of the feed unit directly. Thus, investigating contact stiffness and error is important in optimizing the design and improving the performance of the linear feed unit. In this study, the contact mechanics and the deformation of the roller between the roller and rail are analyzed. Calculation model of the contact stiffness and error based on the Hertz theory and multi-body kinematics are established and the change of the contact angle is also considered. Errors and the contact stiffness curve of five directions and the changes of the slope of the stiffness curve after the load increases to a certain size are obtained. The Motion precision errors of The roller linear feed unit are analyzed. The effectiveness of the proposed models on contact stiffness and error is verified through simulation on a specialized test system of the linear feed unit

  6. Closed-Loop Supply Chain Models with Considering the Environmental Impact

    Directory of Open Access Journals (Sweden)

    Amir Mohajeri

    2014-01-01

    Full Text Available Global warming and climate changes created by large scale emissions of greenhouse gases are a worldwide concern. Due to this, the issue of green supply chain management has received more attention in the last decade. In this study, a closed-loop logistic concept which serves the purposes of recycling, reuse, and recovery required in a green supply chain is applied to integrate the environmental issues into a traditional logistic system. Here, we formulate a comprehensive closed-loop model for the logistics planning considering profitability and ecological goals. In this way, we can achieve the ecological goal reducing the overall amount of CO2 emitted from journeys. Moreover, the profitability criterion can be supported in the cyclic network with the minimum costs and maximum service level. We apply three scenarios and develop problem formulations for each scenario corresponding to the specified regulations and investigate the effect of the regulation on the preferred transport mode and the emissions. To validate the models, some numerical experiments are worked out and a comparative analysis is investigated.

  7. Closed-loop supply chain models with considering the environmental impact.

    Science.gov (United States)

    Mohajeri, Amir; Fallah, Mohammad

    2014-01-01

    Global warming and climate changes created by large scale emissions of greenhouse gases are a worldwide concern. Due to this, the issue of green supply chain management has received more attention in the last decade. In this study, a closed-loop logistic concept which serves the purposes of recycling, reuse, and recovery required in a green supply chain is applied to integrate the environmental issues into a traditional logistic system. Here, we formulate a comprehensive closed-loop model for the logistics planning considering profitability and ecological goals. In this way, we can achieve the ecological goal reducing the overall amount of CO2 emitted from journeys. Moreover, the profitability criterion can be supported in the cyclic network with the minimum costs and maximum service level. We apply three scenarios and develop problem formulations for each scenario corresponding to the specified regulations and investigate the effect of the regulation on the preferred transport mode and the emissions. To validate the models, some numerical experiments are worked out and a comparative analysis is investigated.

  8. Considering Time-Dependency of Social Vulnerability in Crisis Modeling and Management

    Science.gov (United States)

    Aubrecht, C.; Steinnocher, K.; Freire, S.; Loibl, W.; Peters-Anders, J.; Ungar, J.

    2012-04-01

    Crisis and disaster management is much more than the immediate first-response actions following an incident. In many projects the main focus has been on the phase starting at the point when an unwanted event happens and lasting until the activities return to normal routines (i.e., ad hoc reaction rather than proactive mitigation). There has been less emphasis on the other phases of the disaster management cycle such as prevention, preparedness, recovery and reconstruction, even though those phases have a strong influence on the general status of a society and its citizens. Especially the potential of a crisis to escalate into a large-scale disaster is heavily dependent on the overall level of preparedness as well as on the planning of mitigation and response actions and their timely execution. There is a need for improved decision-making support that enables modeling of different crisis scenarios and their impacts according to chosen prevention and response actions. Vulnerability describing the status of a society with respect to an imposed hazard or potential impact is considered a strongly multidisciplinary concept. A central objective of vulnerability assessment is to provide indications where and how people - and more specifically, what kind of people - might be affected by a certain impact. Results should provide decision- and policy-makers with supporting information to target response and mitigation actions adequately. For assessment of the social dimension of vulnerability, population exposure mapping is usually considered the starting point. Integration of social structure and varying aspects of resilience further differentiate situation-specific vulnerability patterns on a local scale. In a disaster risk management context, assessment of human vulnerability has generally been lagging behind hazard analysis efforts. Accurately estimating population exposure is a key component of catastrophe loss modeling, one element of effective integrated risk analysis

  9. An Appropriate Wind Model for Wind Integrated Power Systems Reliability Evaluation Considering Wind Speed Correlations

    Directory of Open Access Journals (Sweden)

    Rajesh Karki

    2013-02-01

    Full Text Available Adverse environmental impacts of carbon emissions are causing increasing concerns to the general public throughout the world. Electric energy generation from conventional energy sources is considered to be a major contributor to these harmful emissions. High emphasis is therefore being given to green alternatives of energy, such as wind and solar. Wind energy is being perceived as a promising alternative. This source of energy technology and its applications have undergone significant research and development over the past decade. As a result, many modern power systems include a significant portion of power generation from wind energy sources. The impact of wind generation on the overall system performance increases substantially as wind penetration in power systems continues to increase to relatively high levels. It becomes increasingly important to accurately model the wind behavior, the interaction with other wind sources and conventional sources, and incorporate the characteristics of the energy demand in order to carry out a realistic evaluation of system reliability. Power systems with high wind penetrations are often connected to multiple wind farms at different geographic locations. Wind speed correlations between the different wind farms largely affect the total wind power generation characteristics of such systems, and therefore should be an important parameter in the wind modeling process. This paper evaluates the effect of the correlation between multiple wind farms on the adequacy indices of wind-integrated systems. The paper also proposes a simple and appropriate probabilistic analytical model that incorporates wind correlations, and can be used for adequacy evaluation of multiple wind-integrated systems.

  10. Who responds to placebos? Considering the "placebo personality" via a transactional model.

    Science.gov (United States)

    Darragh, Margot; Booth, Roger J; Consedine, Nathan S

    2015-01-01

    The placebo effect is now recognised as a genuine psychobiological phenomenon; however, the question of how it can be systematically harnessed to improve health outcomes is not yet clear. One issue that remains unresolved is why some respond to placebos and others do not. A number of traits have been linked to responding, but findings are scattered. In extending prior work, this paper offers three considerations. First, attempts to describe the placebo responder via a single personality trait may be limiting. A synthesis of findings to date suggests placebo responsiveness may reflect a two-faceted construct, with "inward" and "outward" orientation representing the different but related facets of placebo responsiveness. Second, the lack of theoretically driven research may be hindering progress. Personality measures rather than personality theory appear to be driving research and higher order traits are descriptive tools with limited use in predicting behaviour. A biologically based stimulus-response model of personality that considers how individuals respond to certain environmental cues may be more appropriate. Third, a transactional model of placebo responding in which dispositional characteristics interact with environmental contingencies is presented. Responsiveness may manifest in placebo environments where there is a match between an individual's biological trait-like response systems and environmental contingencies. This type of model may be useful in both research and clinical settings. Systematic consideration of how different individuals might respond to different placebo environments might facilitate identification of stable individual characteristics predictive of responding. The ability to determine who is responsive to placebo treatments, and in what context, may enable the matching of individual to treatment, thereby maximising the effectiveness of treatment and minimising possible iatrogenic harm. In the increasingly overtaxed modern health care

  11. KdV-Burgers equation in a new continuum model based on full velocity difference model considering anticipation effect

    Science.gov (United States)

    Cheng, Rongjun; Ge, Hongxia; Wang, Jufeng

    2017-09-01

    In this paper, a new continuum model based on full velocity difference car following model is developed with the consideration of driver's anticipation effect. By applying the linear stability theory, the new model's linear stability is obtained. Through nonlinear analysis, the KdV-Burgers equation is derived to describe the propagating behavior of traffic density wave near the neutral stability line. Numerical simulation shows that the new model possesses the local cluster, and it is capable of explaining some particular traffic phenomena Numerical results show that when considering the effects of anticipation, the traffic jams can be suppressed efficiently. The key improvement of this new model is that the anticipation effect can improve the stability of traffic flow.

  12. Mathematical modelling for Zoonotic Visceral Leishmaniasis dynamics: A new analysis considering updated parameters and notified human Brazilian data

    Directory of Open Access Journals (Sweden)

    Helio Junji Shimozako

    2017-05-01

    Full Text Available Brazil is one of the highest endemic countries for Zoonotic Visceral Leishmaniasis: according to the Brazilian Ministry of Health, the annual number of new human cases and deaths due to this disease has been increasing for the last 20 years. In addition, regarding the Americas, the specific relationship between canine and human for Visceral Leishmaniasis dynamics is still not well understood. In this work we propose a new model for Zoonotic Visceral Leishmaniasis, based on the models previously published by Burattini et al. (1998 and Ribas et al. (2013. Herein, we modeled the disease dynamics using a modified set of differential equations from those two authors, considering the same assumptions (inclusion of human, dog and sandfly populations, all constants over time. From this set of equations we were able to calculate the basic reproduction number R0 and to analyze the stability and sensitivity of the system to the parameters variability. As main result, when the stability of the system is reached, the normalized reporting human cases rate is estimated in 9.12E-08/day. This estimation is very close to the 2015 report from Araçatuba city, 5.69E-08/day. We also observed from stability and sensitivity analysis that the activity of sandfly population is critical to introduction and maintenance of Zoonotic Visceral Leishmaniasis in the population. In addition, the importance of dog as source of infection concentrates on latent dog, since it does not show clinical symptoms and signs and, therefore, has a great contribution to disease dissemination. As conclusion, considering the presently ethical issues regarding to elimination of positive dog in Brazil and the highly sensitivity of disease dynamics on sandfly population, we recommend that the sandfly population control should be prioritized. Keywords: Zoonotic Visceral Leishmaniasis, Disease dynamics, Mathematical modelling, Epidemiology

  13. Properties of type IV plaster considering variation in the mold/model position during setting stage

    Directory of Open Access Journals (Sweden)

    Tarcisio José de Arruda Paes Junior

    2010-04-01

    Full Text Available Objective: To assess the influence of the position of the mold during the setting stage of type IV stone plaster Durone (Dentsply Ind. Com., Rio de Janeiro, Brazil, on the following properties: surface hardness and roughness. Methods: For the roughness test, two groups (n=6 in the form of pellets were prepared. In the first group, the surface of the base of the device was turned down during the plaster setting stage (N, in the second group this position was inverted, which has been described as an act of capsize it (E. For analysis, a roughness meter with reading precision of 0.01 μm was used. With regard to the hardness analysis, two groups with conical-shaped samples were obtained. The plasters were left to set under the same conditions of the mold/model position described for the previous experiment. Hardness measurement was performed in a durometer with a spherical penetrating tip for Rockwell readout. Three measurements were performed for each test specimen in both tests. Results: The hardness (N - 39.8, standard deviation = 3.3, E - 30.8, standard deviation = 5.6 and roughness data (N - 0.67, standard deviation = 0.17, E - 0.74, standard deviation = 0.13 submitted to the Student’s-t test (5% showed no statistically significant differences for the roughness test (0.489, but showed statistically significant differences for the hardness test (0.014. Conclusion: The variation in the mold/model position influenced the final characteristics of the specimens in terms of hardness, since those obtained with the capsize technique showed lower surface hardness, whereas for roughness these differences were not statistically significant.

  14. Custom implants for medialization laryngoplasty: a model that considers tissue compression.

    Science.gov (United States)

    Benninger, Michael S; Chota, Rebecca L; Bryson, Paul C; Drake, Richard L

    2015-05-01

    Unilateral vocal fold paralysis can be treated with surgical medialization with a carved silastic implant. One challenge to this approach is anticipating the dimensions of the implant for adequate medialization. The purpose of this study was to develop a predictive model for implant design based on a patient's unique laryngeal anatomy and considering compression of the vocal fold. Retrospective chart review, prospective cadaver study, and prospective patient study. A retrospective chart review was performed on patients who received silastic medialization laryngoplasty with favorable outcome and who had preoperative computed tomography. Data including Voice Handicap Index, maximum phonation time, and implant dimensions were collected from medical records, and laryngeal measurements were taken from preoperative imaging. Measurements were taken from computed tomography scans of three cadavers who underwent laryngoplasty for this study. Tissue compression (TC) was calculated and analyzed. A model to predict successful implant dimensions was developed and applied prospectively in 16 patients. Eleven patients from the chart review and three cadavers were included. Of all laryngeal metrics, width of the vocal fold at maximal medialization was most strongly correlated to TC (r = 0.728). Linear regression was performed (y = 0.50x - 1.2, R(2) = 0.53, P = 0.005, F = 12.39). Of the prospective patients, 15 of 16 demonstrated complete glottis closure with the premeasured silastic implant. Vocal fold compression by silastic implants is linearly correlated with vocal fold-width at maximal medialization. A predictive formula was generated to anticipate TC and was successful in designing custom implants for patients. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  15. Nonlinear dynamic model of a gear-rotor-bearing system considering the flash temperature

    Science.gov (United States)

    Gou, Xiangfeng; Zhu, Lingyun; Qi, Changjun

    2017-12-01

    The instantaneous flash temperature is an important factor for gears in service. To investigate the effect of the flash temperature of a tooth surface on the dynamics of the spur gear system, a modified nonlinear dynamic model of a gear-rotor-bearing system is established. The factors such as the contact temperature of the tooth surface, time-varying stiffness, tooth surface friction, backlash, the comprehensive transmission error and so on are considered. The flash temperature of a tooth surface of pinion and gear is formulated according to Blok's flash temperature theory. The mathematical expression of the contact temperature of the tooth surface varied with time is derived and the tooth profile deformation caused by the change of the flash temperature of the tooth surface is calculated. The expression of the mesh stiffness varied with the flash temperature of the tooth surface is derived based on Hertz contact theory. The temperature stiffness is proposed and added to the nonlinear dynamic model of the system. The influence of load on the flash temperature of the tooth surface is analyzed in the parameters plane. The variation of the flash temperature of the tooth surface is studied. The numerical results indicate that the calculated method of the flash temperature of the gear tooth surface is effective and it can reflect the rules for the change of gear meshing temperature and sliding of the gear tooth surface. The effects of frequency, backlash, bearing clearance, comprehensive transmission error and time-varying stiffness on the nonlinear dynamics of the system are analyzed according to the bifurcation diagrams, Top Lyapunov Exponent (TLE) spectrums, phase portraits and Poincaré maps. Some nonlinear phenomena such as periodic bifurcation, grazing bifurcation, quasi-periodic bifurcation, chaos and its routes to chaos are investigated and the critical parameters are identified. The results provide an understanding of the system and serve as a useful reference

  16. Dynamic modeling and experiment of a new type of parallel servo press considering gravity counterbalance

    Science.gov (United States)

    He, Jun; Gao, Feng; Bai, Yongjun; Wu, Shengfu

    2013-11-01

    The large capacity servo press is traditionally realized by means of redundant actuation, however there exist the over-constraint problem and interference among actuators, which increases the control difficulty and the product cost. A new type of press mechanism with parallel topology is presented to develop the mechanical servo press with high stamping capacity. The dynamic model considering gravity counterbalance is proposed based on the virtual work principle, and then the effect of counterbalance cylinder on the dynamic performance of the servo press is studied. It is found that the motor torque required to operate the press is a lot less than the others when the ratio of the counterbalance force to the gravity of ram is in the vicinity of 1.0. The stamping force of the real press prototype can reach up to 25 MN on the position of 13 mm away from the bottom dead center. The typical deep-drawing process with 1 200 mm stroke at 8 strokes per minute is proposed by means of five order polynomial. On this process condition, the driving torques are calculated based on the above dynamic model and the torque measuring test is also carried out on the prototype. It is shown that the curve trend of calculation torque is consistent to the measured result and that the average error is less than 15%. The parallel mechanism is introduced into the development of large capacity servo press to avoid the over-constraint and interference of traditional redundant actuation, and its dynamic characteristics with gravity counterbalance are presented.

  17. A mathematical model of urban distribution electro-network considering its future development

    Directory of Open Access Journals (Sweden)

    A. P. Karpenko

    2014-01-01

    Full Text Available A distribution urban power supply network (further, the power supply network is the network of urban scale. Designed to transfer and distribute electric power it represents a set of transforming and distributional substations and power lines to connect them. We consider a problem of the prospective development of power supply network (PDPSN as a task to define the ways for its optimum development in terms of configuration, equipment loads, parameters, etc., as well as from the point of view of need and terms to put into service the new objects of the power supply network.The program systems represented in the market allow us to calculate parameters of power supply systems, network operating modes, to display power supply schemes, and to make technical documentation, but they do not support the CAD of optimum network topology taking into account factors of the prospective urban development.A main objective of the work is development of mathematical model of the power supply network taking into account its prospective development. Based on this model the task is set to optimize the prospective power supply network development through the solving a problem of multi-criteria structural and parametrical optimization. Expediency is proved to use a method of reduction to the one-criteria task by means of this or that scalar convolution to solve this task.The specified problem of one-criteria optimization of PDPSN represents a problem of continuous-discrete-integer programming. The paper proves its representation as a problem of discrete programming based on the discrete approximation of possible regions to construct new transforming and distributional substations.

  18. Considering the energy, water and food nexus: Towards an integrated modelling approach

    International Nuclear Information System (INIS)

    Bazilian, Morgan; Rogner, Holger; Howells, Mark; Hermann, Sebastian; Arent, Douglas; Gielen, Dolf; Steduto, Pasquale; Mueller, Alexander; Komor, Paul; Tol, Richard S.J.; Yumkella, Kandeh K.

    2011-01-01

    The areas of energy, water and food policy have numerous interwoven concerns ranging from ensuring access to services, to environmental impacts to price volatility. These issues manifest in very different ways in each of the three “spheres”, but often the impacts are closely related. Identifying these interrelationships a priori is of great importance to help target synergies and avoid potential tensions. Systems thinking is required to address such a wide swath of possible topics. This paper briefly describes some of the linkages at a high-level of aggregation – primarily from a developing country perspective – and via case studies, to arrive at some promising directions for addressing the nexus. To that end, we also present the attributes of a modelling framework that specifically addresses the nexus, and can thus serve to inform more effective national policies and regulations. While environmental issues are normally the ‘cohesive principle’ from which the three areas are considered jointly, the enormous inequalities arising from a lack of access suggest that economic and security-related issues may be stronger motivators of change. Finally, consideration of the complex interactions will require new institutional capacity both in industrialised and developing countries.

  19. Transient Inverse Calibration of Site-Wide Groundwater Model to Hanford Operational Impacts from 1943 to 1996--Alternative Conceptual Model Considering Interaction with Uppermost Basalt Confined Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Vermeul, Vincent R.; Cole, Charles R.; Bergeron, Marcel P.; Thorne, Paul D.; Wurstner, Signe K.

    2001-08-29

    The baseline three-dimensional transient inverse model for the estimation of site-wide scale flow parameters, including their uncertainties, using data on the transient behavior of the unconfined aquifer system over the entire historical period of Hanford operations, has been modified to account for the effects of basalt intercommunication between the Hanford unconfined aquifer and the underlying upper basalt confined aquifer. Both the baseline and alternative conceptual models (ACM-1) considered only the groundwater flow component and corresponding observational data in the 3-Dl transient inverse calibration efforts. Subsequent efforts will examine both groundwater flow and transport. Comparisons of goodness of fit measures and parameter estimation results for the ACM-1 transient inverse calibrated model with those from previous site-wide groundwater modeling efforts illustrate that the new 3-D transient inverse model approach will strengthen the technical defensibility of the final model(s) and provide the ability to incorporate uncertainty in predictions related to both conceptual model and parameter uncertainty. These results, however, indicate that additional improvements are required to the conceptual model framework. An investigation was initiated at the end of this basalt inverse modeling effort to determine whether facies-based zonation would improve specific yield parameter estimation results (ACM-2). A description of the justification and methodology to develop this zonation is discussed.

  20. Mathematical Decision Models Applied for Qualifying and Planning Areas Considering Natural Hazards and Human Dealing

    Science.gov (United States)

    Anton, Jose M.; Grau, Juan B.; Tarquis, Ana M.; Sanchez, Elena; Andina, Diego

    2014-05-01

    The authors were involved in the use of some Mathematical Decision Models, MDM, to improve knowledge and planning about some large natural or administrative areas for which natural soils, climate, and agro and forest uses where main factors, but human resources and results were important, natural hazards being relevant. In one line they have contributed about qualification of lands of the Community of Madrid, CM, administrative area in centre of Spain containing at North a band of mountains, in centre part of Iberian plateau and river terraces, and also Madrid metropolis, from an official study of UPM for CM qualifying lands using a FAO model from requiring minimums of a whole set of Soil Science criteria. The authors set first from these criteria a complementary additive qualification, and tried later an intermediate qualification from both using fuzzy logic. The authors were also involved, together with colleagues from Argentina et al. that are in relation with local planners, for the consideration of regions and of election of management entities for them. At these general levels they have adopted multi-criteria MDM, used a weighted PROMETHEE, and also an ELECTRE-I with the same elicited weights for the criteria and data, and at side AHP using Expert Choice from parallel comparisons among similar criteria structured in two levels. The alternatives depend on the case study, and these areas with monsoon climates have natural hazards that are decisive for their election and qualification with an initial matrix used for ELECTRE and PROMETHEE. For the natural area of Arroyos Menores at South of Rio Cuarto town, with at North the subarea of La Colacha, the loess lands are rich but suffer now from water erosions forming regressive ditches that are spoiling them, and use of soils alternatives must consider Soil Conservation and Hydraulic Management actions. The use of soils may be in diverse non compatible ways, as autochthonous forest, high value forest, traditional

  1. Previously published midazolam-alfentanil response surface model cannot predict patient response well in gastrointestinal endoscopy sedation.

    Science.gov (United States)

    Liou, Jing-Yang; Ting, Chien-Kun; Huang, Yu-Ying; Tsou, Mei-Yung

    2016-03-01

    A response surface model is a mathematical model used to predict multiple-drug pharmacodynamic interactions. With the use of a previously published volunteer model, we tested the accuracy of the midazolam-alfentanil response surface model during gastrointestinal endoscopy. We enrolled 35 adult patients scheduled for combined endoscopic procedures. Patients were sedated with intravenous midazolam and alfentanil, and monitored with real-time auditory evoked potential. Sedation Observer's Assessment of Alertness/Sedation (OAA/S) scores were recorded by an independent observer every 2 minutes. Patients with OAA/S scores of ≥ 4 were designated as "awake". Pharmacokinetic profiles were calculated using the TIVA trainer. The published response surface model was modified to make estimations more reasonable. Patient response (OAA/S score ≥ 4 or response during gastrointestinal endoscopic procedure sedation. Accuracy in predicting an OAA/S score of response ranged from 0.04% to 2.94% at the time of arousal (OAA/S score ≥ 4) and from 0.24% to 15.55% when the patient was asleep (OAA/S score response of patients undergoing sedated gastrointestinal endoscopic procedures. Future model parameter adjustments are required. Copyright © 2016. Published by Elsevier Taiwan LLC.

  2. Validation of a Previously Developed Geospatial Model That Predicts the Prevalence of Listeria monocytogenes in New York State Produce Fields.

    Science.gov (United States)

    Weller, Daniel; Shiwakoti, Suvash; Bergholz, Peter; Grohn, Yrjo; Wiedmann, Martin; Strawn, Laura K

    2016-02-01

    Technological advancements, particularly in the field of geographic information systems (GIS), have made it possible to predict the likelihood of foodborne pathogen contamination in produce production environments using geospatial models. Yet, few studies have examined the validity and robustness of such models. This study was performed to test and refine the rules associated with a previously developed geospatial model that predicts the prevalence of Listeria monocytogenes in produce farms in New York State (NYS). Produce fields for each of four enrolled produce farms were categorized into areas of high or low predicted L. monocytogenes prevalence using rules based on a field's available water storage (AWS) and its proximity to water, impervious cover, and pastures. Drag swabs (n = 1,056) were collected from plots assigned to each risk category. Logistic regression, which tested the ability of each rule to accurately predict the prevalence of L. monocytogenes, validated the rules based on water and pasture. Samples collected near water (odds ratio [OR], 3.0) and pasture (OR, 2.9) showed a significantly increased likelihood of L. monocytogenes isolation compared to that for samples collected far from water and pasture. Generalized linear mixed models identified additional land cover factors associated with an increased likelihood of L. monocytogenes isolation, such as proximity to wetlands. These findings validated a subset of previously developed rules that predict L. monocytogenes prevalence in produce production environments. This suggests that GIS and geospatial models can be used to accurately predict L. monocytogenes prevalence on farms and can be used prospectively to minimize the risk of preharvest contamination of produce. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  3. Widespread confusion in the modeling of Europa's magnetospheric interaction: what the potential modeler should consider before getting started

    Science.gov (United States)

    Cassidy, T. A.

    2016-12-01

    Understanding Europa's interaction with Jupiter's magnetosphere is a critical part of the ocean sounding objective of the upcoming Clipper mission and interpretation of these observations will require modeling efforts that build upon studies done over the last four decades. Unfortunately, these studies are often confusing and contradictory. There is, as yet, no community consensus on the assumptions and parameters that go into such models. There is enough uncertainty in this problem that I cannot tell anyone, with certainty, what they should and should not do, but in this presentation I will outline what modelers should at least consider before starting. The most important consideration that is often missing in the literature is plasma flow diversion. Many papers assume that Europa's interaction is lunar-like; a completely absorbing barrier. Data and plasma models show that there is likely significant diversion, and such diversion could prevent the bulk of magnetospheric plasa particles from reaching the surface. On the other hand, some models likely overestimate the amount of diversion: we do know that a significant amount of plasma must reach the surface in order to produce the atmosphere via sputtering and radiolysis, but most plasma models usually treat the atmosphere as a fixed boundary condition. A second consideration is energy range of particles responsible for radiolysis and sputtering. The particles bombarding the surface range from thermal plasma (eV-keV) to non-thermal (keV-MeV), but to many modelers, it seems, these are indistinguishable despite drastic differences in how these populations interact with the moon. To illustrate this confusion, the attached figure shows the O2 source rate (O2 is likely the dominant atmospheric component) from published Europa atmosphere/plasma models. There is little agreement on either the source rate or the particle population responsible for its production. Finally, I will discuss how experiences with other planetary

  4. Optimal urban water conservation strategies considering embedded energy: coupling end-use and utility water-energy models.

    Science.gov (United States)

    Escriva-Bou, A.; Lund, J. R.; Pulido-Velazquez, M.; Spang, E. S.; Loge, F. J.

    2014-12-01

    Although most freshwater resources are used in agriculture, a greater amount of energy is consumed per unit of water supply for urban areas. Therefore, efforts to reduce the carbon footprint of water in cities, including the energy embedded within household uses, can be an order of magnitude larger than for other water uses. This characteristic of urban water systems creates a promising opportunity to reduce global greenhouse gas emissions, particularly given rapidly growing urbanization worldwide. Based on a previous Water-Energy-CO2 emissions model for household water end uses, this research introduces a probabilistic two-stage optimization model considering technical and behavioral decision variables to obtain the most economical strategies to minimize household water and water-related energy bills given both water and energy price shocks. Results show that adoption rates to reduce energy intensive appliances increase significantly, resulting in an overall 20% growth in indoor water conservation if household dwellers include the energy cost of their water use. To analyze the consequences on a utility-scale, we develop an hourly water-energy model based on data from East Bay Municipal Utility District in California, including the residential consumption, obtaining that water end uses accounts for roughly 90% of total water-related energy, but the 10% that is managed by the utility is worth over 12 million annually. Once the entire end-use + utility model is completed, several demand-side management conservation strategies were simulated for the city of San Ramon. In this smaller water district, roughly 5% of total EBMUD water use, we found that the optimal household strategies can reduce total GHG emissions by 4% and utility's energy cost over 70,000/yr. Especially interesting from the utility perspective could be the "smoothing" of water use peaks by avoiding daytime irrigation that among other benefits might reduce utility energy costs by 0.5% according to our

  5. Ignition and Growth Modeling of Detonating LX-04 (85% HMX / 15% VITON) Using New and Previously Obtained Experimental Data

    Science.gov (United States)

    Tarver, Craig

    2017-06-01

    An Ignition and Growth reactive flow model for detonating LX-04 (85% HMX / 15% Viton) was developed using new and previously obtained experimental data on: cylinder test expansion; wave curvature; failure diameter; and laser interferometric copper and tantalum foil free surface velocities and LiF interface particle velocity histories. A reaction product JWL EOS generated by the CHEETAH code compared favorably with the existing, well normalized LX-04 product JWL when both were used with the Ignition and Growth model. Good agreement with all existing experimental data was obtained. Keywords: LX-04, HMX, detonation, Ignition and Growth PACS:82.33.Vx, 82.40.Fp This work was performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

  6. Modeling College Graduation GPA Considering Equity in Admissions: Evidence from the University of Puerto Rico

    Science.gov (United States)

    Matos-Díaz, Horacio; García, Dwight

    2014-01-01

    Over concerns about private school students' advantages in standardized tests, beginning in 1995-96 the University of Puerto Rico (UPR) implemented a new admissions formula that reduced the weight they previously had in the General Admissions Index (GAI), on which its admissions decisions are based. This study seeks to determine the possible…

  7. A Combined Reliability Model of VSC-HVDC Connected Offshore Wind Farms Considering Wind Speed Correlation

    DEFF Research Database (Denmark)

    Guo, Yifei; Gao, Houlei; Wu, Qiuwei

    2017-01-01

    and WTGs outage. The wind speed correlation between different WFs is included in the two-dimensional multistate WF model by using an improved k-means clustering method. Then, the entire system with two WFs and a threeterminal VSC-HVDC system is modeled as a multi-state generation unit. The proposed model...

  8. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

    Science.gov (United States)

    Mirzabozorg, H.; Hariri-Ardebili, M. A.; Shirkhan, M.; Seyed-Kolbadi, S. M.

    2014-01-01

    The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams. PMID:24695817

  9. Do Stochastic Traffic Assignment Models Consider Differences in Road Users Utility Functions?

    DEFF Research Database (Denmark)

    Nielsen, Otto Anker

    1996-01-01

    The early stochastic traffic assignment models (e.g. Dial, 1971) build on the assump-tion that different routes are independent (the logit-model concept). Thus, the models gave severe problems in networks with overlapping routes. Daganzo & Sheffi (1977) suggested to use probit based models...... to overcome this problem. Sheffi & Powell (1981) presented a practically operational solution algorithm in which the travel resistance for each road segment is adjusted according to a Monte Carlo simulation following the Normal-distribution. By this the road users’ ‘perceived travel resistances’ are simulated....... A similar concept is used as a part of the Sto-chastic User Equilibrium model (SUE) suggested by Daganzo and Sheffi (1977) and operationalized by Sheffi & Powell (1982). In the paper it is discussed whether this way of modelling the ‘perceived travel resistance’ is sufficient to describe the road users...

  10. An improved car-following model considering influence of other factors on traffic jam

    Science.gov (United States)

    Ge, Hong-xia; Meng, Xiang-pei; Ma, Jian; Lo, Siu-ming

    2012-12-01

    In the Letter, a modified car-following model is presented, in which, the effects of vehicles (or non-motor vehicles) on other lanes without isolation belts are taken into account. The stability condition of the model is obtained by using the control theory method. To check the validity of the present theoretical scheme, the numerical simulation is carried out for the new car-following model, and the simulation result is consistent with the theoretical analysis.

  11. KdV-Burgers equation in the modified continuum model considering anticipation effect

    Science.gov (United States)

    Liu, Huaqing; Zheng, Pengjun; Zhu, Keqiang; Ge, Hongxia

    2015-11-01

    The new continuum model mentioned in this paper is developed based on optimal velocity car-following model, which takes the drivers' anticipation effect into account. The critical condition for traffic flow is derived, and nonlinear analysis shows density waves occur in traffic flow because of the small disturbance. Near the neutral stability line, the KdV-Burgers equation is derived and one of the solutions is given. Numerical simulation is carried out to show the local cluster described by the model.

  12. A Stochastic Traffic Assignment Model Considering Differences in Passengers Utility Functions

    DEFF Research Database (Denmark)

    Nielsen, Otto Anker

    1997-01-01

    The paper presents a framework for public transport assignment that builds on the probit-based model of Sheffi & Powell (1981 & 1982). Hereby, the problems with overlapping routes that occur in many public transport models can be avoided. In the paper, the probit-based model in its pure form....... This is both due to the probit model’s ability to describe overlapping routes and due to the many different weights and distributions that make it possible to calibrate the model. In practice, the many parameters might also be the methods main weakness, since this complicates the calibration....

  13. An Extended System Frequency Response Model Considering Wind Power Participation in Frequency Regulation

    Directory of Open Access Journals (Sweden)

    Yi Tang

    2017-11-01

    Full Text Available With increasing penetration of wind power into the power system, wind power participation in frequency regulation is regarded as a beneficial strategy to improve the dynamic frequency response characteristics of power systems. The traditional power system frequency response (SFR model, which only includes synchronous generators, is no longer suitable for power systems with high penetrated wind power. An extended SFR model, based on the reduced-order model of wind turbine generator (WTG and the traditional SFR model, is presented in this paper. In the extended SFR model, the reduced-order model of WTG with combined frequency control is deduced by employing small signal analysis theory. Afterwards, the stability analysis of a closed-loop control system for the extended SFR model is carried out. Time-domain simulations using a test system are performed to validate the effectiveness of the extended SFR model; this model can provide a simpler, clearer and faster way to analyze the dynamic frequency response characteristic for a high-wind integrated power systems. The impact of additional frequency control parameters and wind speed disturbances on the system dynamic frequency response characteristics are investigated.

  14. Determining the Most Efficient Supplier Considering Imprecise Data in Data Envelopment Analysis (DEA, a extension for Toloo and Nalchigar's model

    Directory of Open Access Journals (Sweden)

    Morteza Rahmani

    2017-03-01

    Full Text Available Supplier selection in supply chain as a multi-criteria decision making problem (containing both qualitative and quantitative criteria is one of the main factors in a successful supply chain. To this purpose, Toloo and Nalchigar (2011 proposed an integrated data envelopment analysis (DEA model to find the most efficient (best supplier by considering imprecise data. In this paper, it will be shown that their model randomly selects an efficient supplier as the most efficient and therefore their model cannot find the most efficient supplier correctly. We also explain some other problems in this model and propose a modified model to resolve the drawbacks. The proposed model in this paper finds the most efficient supplier considering imprecise data by solving only one mixed integer linear programming. In addition, a new algorithm is proposed for determining and ranking other efficient suppliers. Afficiency of the proposed approach is explained by considering imprecise data for 18 suppliers.

  15. Object based classification of high resolution data in urban areas considering digital surface models

    OpenAIRE

    Oczipka, Martin Eckhard

    2010-01-01

    Over the last couple of years more and more analogue airborne cameras were replaced by digital cameras. Digitally recorded image data have significant advantages to film based data. Digital aerial photographs have a much better radiometric resolution. Image information can be acquired in shaded areas too. This information is essential for a stable and continuous classification, because no data or unclassified areas should be as small as possible. Considering this technological progress, on...

  16. Fluid stiction modeling for quickly separating plates considering the liquid tensile strength

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik C.

    2015-01-01

    the time dependent fluid stiction phenomenon, including a fluid tensile strength and cavitation effects, is proposed. The model is based on Reynolds theory, and the pressure distribution in the liquid zone is solved analytically for each time step, leading to a computationally efficient model without...... given that proper selections of liquid tensile strength and initial plate distance are made....

  17. Comparison of Transient Behaviors of Wind Turbines with DFIG Considering the Shaft Flexible Models

    DEFF Research Database (Denmark)

    Chen, Zhe; Ye, Ren-jie; Hui, Li

    2008-01-01

    on the electrical transient performances of doubly fed induction generator (DFIG) wind turbines with different operationally states is investigated. In order to compare the transient performances of DFIG wind turbines during electrical transients, a DFIG model with simple one-mass lumped model and a two-mass shaft...

  18. Configurable product design considering the transition of multi-hierarchical models

    Science.gov (United States)

    Ren, Bin; Qiu, Lemiao; Zhang, Shuyou; Tan, Jianrong; Cheng, Jin

    2013-03-01

    The current research of configurable product design mainly focuses on how to convert a predefined set of components into a valid set of product structures. With the scale and complexity of configurable products increasing, the interdependencies between customer demands and product structures grow up as well. The result is that existing product structures fails to satisfy the individual customer requirements and hence product variants are needed. This paper is aimed to build a bridge between customer demands and product structures in order to make demand-driven fast response design feasible. First of all, multi-hierarchical models of configurable product design are established with customer demand model, technical requirement model and product structure model. Then, the transition of multi-hierarchical models among customer demand model, technical requirement model and product structure model is solved with fuzzy analytic hierarchy process (FAHP) and the algorithm of multi-level matching. Finally, optimal structure according to the customer demands is obtained with the calculation of Euclidean distance and similarity of some cases. In practice, the configuration design of a clamping unit of injection molding machine successfully performs an optimal search strategy for the product variants with reasonable satisfaction to individual customer demands. The proposed method can automatically generate a configuration design with better alternatives for each product structures, and shorten the time of finding the configuration of a product.

  19. Modeling of wind turbine vortex generators in considering the inter-effects between arrays

    DEFF Research Database (Denmark)

    Zhao, Zhenzhou; Shen, Wenzhong; Wang, Ruixin

    2017-01-01

    Vortex generators (VGs) are commonly placed on wind turbine blades to delay flow separation in the boundary layer. VGs can be parametrically modeled in computational fluid dynamics for effective and efficient simulations of wind blade flow fields. Many researchers have studied the vortex circulat......Vortex generators (VGs) are commonly placed on wind turbine blades to delay flow separation in the boundary layer. VGs can be parametrically modeled in computational fluid dynamics for effective and efficient simulations of wind blade flow fields. Many researchers have studied the vortex....... Compared to the solid VG model, the array type model has similar streamlines and surface pressure coefficients on the suction surface. The array type VG model can effectively reduce the number of grid points and yield highly accurate predictions of wind turbine blade aerodynamic characteristics....

  20. Path Tracking Control of Automatic Parking Cloud Model considering the Influence of Time Delay

    Directory of Open Access Journals (Sweden)

    Yiding Hua

    2017-01-01

    Full Text Available This paper establishes the kinematic model of the automatic parking system and analyzes the kinematic constraints of the vehicle. Furthermore, it solves the problem where the traditional automatic parking system model fails to take into account the time delay. Firstly, based on simulating calculation, the influence of time delay on the dynamic trajectory of a vehicle in the automatic parking system is analyzed under the transverse distance Dlateral between different target spaces. Secondly, on the basis of cloud model, this paper utilizes the tracking control of an intelligent path closer to human intelligent behavior to further study the Cloud Generator-based parking path tracking control method and construct a vehicle path tracking control model. Moreover, tracking and steering control effects of the model are verified through simulation analysis. Finally, the effectiveness and timeliness of automatic parking controller in the aspect of path tracking are tested through a real vehicle experiment.

  1. Models for high cell density bioreactors must consider biomass volume fraction: Cell recycle example.

    Science.gov (United States)

    Monbouquette, H G

    1987-06-01

    Intrinsic models, which take into account biomass volume fraction, must be formulated for adequate simulation of high-biomass-density fermentations with cell recycle. Through comparison of corresponding intrinsic and non-intrinsic models in dimensionless form, constraints for non-intrinsic model usage in terms of biokinetic and fermenter operating parameters can be identified a priori. Analysis of a simple product-inhibition model indicates that the non-intrinsic approach is suitable only when the attainable biomass volume fraction in the fermentation broth is less than about 0.10. Inappropriate application of a non-intrinsic model can lead to gross errors in calculated substrate and product concentrations, substrate conversion, and volumetric productivity.

  2. Models for high cell density bioreactors must consider biomass volume fraction: cell recycle example

    Energy Technology Data Exchange (ETDEWEB)

    Monbouquette, H.G.

    1987-06-01

    Intrinsic models, which take into account biomass volume fraction, must be formulated for adequate simulation of high-biomass-density fermentations with cell recycle. Through comparison of corresponding intrinsic and non-intrinsic models in dimensionless form, constraints for non-intrinsic model usage in terms of biokinetic and fermenter operating parameters can be identified a priori. Analysis of a simple product-inhibition model indicates that the non-intrinsic approach is suitable only when the attainable biomass volume fraction in the fermentation broth is less than about 0.10. Inappropriate application of a non-intrinsic model can lead to gross errors in calculated substrate and product concentrations, substrate conversion, and volumetric productivity. (Refs. 14).

  3. A new simulation model for assessing aircraft emergency evacuation considering passenger physical characteristics

    International Nuclear Information System (INIS)

    Liu, Yu; Wang, Weijie; Huang, Hong-Zhong; Li, Yanfeng; Yang, Yuanjian

    2014-01-01

    Conducting a real aircraft evacuation trial is oftentimes unaffordable as it is extremely expensive and may cause severe injury to participants. Simulation models as an alternative have been used to overcome the aforementioned issues in recent years. This paper proposes a new simulation model for emergency evacuation of civil aircraft. Its unique features and advantages over the existing models are twofold: (1) passengers' critical physical characteristics, e.g. waist size, gender, age, and disabilities, which impact the movement and egress time of individual evacuee from a statistical viewpoint, are taken into account in the new model. (2) Improvements are made to enhance the accuracy of the simulation model from three aspects. First, the staggered mesh discretization method together with the agent-based approach is utilized to simulate movements of individual passengers in an emergency evacuation process. Second, each node discretized to represent cabin space in the new model can contain more than one passenger if they are moving in the same direction. Finally, each individual passenger is able to change his/her evacuation route in a real-time manner based upon the distance from the current position to the target exit and the queue length. The effectiveness of the proposed simulation model is demonstrated on Boeing 767-300 aircraft. - Highlights: • A new simulation model of aircraft emergency evacuation is developed. • Some critical physical characteristics of passengers', e.g. waist size, gender, age, and disabilities, are taken into account in the new model. • An agent-based approach along with a multi-level fine network representation is used. • Passengers are able to change their evacuation routes in a real-time manner based upon distance and length of queue

  4. Modeling and Experimental Tests of a Mechatronic Device to Measure Road Profiles Considering Impact Dynamics

    DEFF Research Database (Denmark)

    Souza, A.; Santos, Ilmar

    2002-01-01

    dynamics is led with help of a set of non-linear equations of motion obtained using Newton-Euler-Jourdain´s Method. Such a set of equation is numerically solved and the theoretical results are compared with experimental carried out with a laboratory prototype. Comparisons show that the theoretical model...... the mechanism components. By modeling impacts between a wheel and the road by Newton´s Law, the complete dynamics of the system can be predicted, and the operational range (velocity limits) of the mechanism can be defined based on the mathematical model. Key words: multibody dynamics, impact dynamics and road...

  5. Detection and Alert of muscle fatigue considering a Surface Electromyography Chaotic Model

    International Nuclear Information System (INIS)

    Herrera, V; Romero, J F; Amestegui, M

    2011-01-01

    This work propose a detection and alert algorithm for muscle fatigue in paraplegic patients undergoing electro-therapy sessions. The procedure is based on a mathematical chaotic model emulating physiological signals and Continuous Wavelet Transform (CWT). The chaotic model developed is based on a logistic map that provides suitable data accomplishing some physiological signal class patterns. The CWT was applied to signals generated by the model and the resulting vector was obtained through Total Wavelet Entropy (TWE). In this sense, the presented work propose a viable and practical alert and detection algorithm for muscle fatigue.

  6. Detection and Alert of muscle fatigue considering a Surface Electromyography Chaotic Model

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, V; Romero, J F [Engineering, Modeling and Applied Social Sciences Center, ABC Federal University, Santo Andr - SP (Brazil); Amestegui, M, E-mail: victoria.herrera@ufabc.edu.br [Engineering Faculty, Electronics Engineering, Universidad Mayor de San Andres, La Paz (Bolivia, Plurinational State of)

    2011-03-01

    This work propose a detection and alert algorithm for muscle fatigue in paraplegic patients undergoing electro-therapy sessions. The procedure is based on a mathematical chaotic model emulating physiological signals and Continuous Wavelet Transform (CWT). The chaotic model developed is based on a logistic map that provides suitable data accomplishing some physiological signal class patterns. The CWT was applied to signals generated by the model and the resulting vector was obtained through Total Wavelet Entropy (TWE). In this sense, the presented work propose a viable and practical alert and detection algorithm for muscle fatigue.

  7. The cosmic dust analyzer: Experimental evaluation of an impact ionization model. [considering thermal equilibrium plasma

    Science.gov (United States)

    Friichtenicht, J. F.; Roy, N. L.; Becker, D. G.

    1973-01-01

    A thermal equilibrium plasma model is used to process data from an impact ionization time-of-flight mass spectrometer in order to convert the raw ion data to relative abundances of the elemental constituents of cosmic dust particles.

  8. The Influence Factor Model for the Popularity of Mobile Phone without Considering the Price Factor

    Science.gov (United States)

    Long, Hongming; Peng, Diefei; Wu, Hailin; Yang, Zihui

    2018-01-01

    Based on the statistical data like economic development, social development, population indicator and so on, this paper establishes the linear regression model which influences the popularity rate of mobile phone users.

  9. Modeling and advanced sliding mode controls of crawler cranes considering wire rope elasticity and complicated operations

    Science.gov (United States)

    Tuan, Le Anh; Lee, Soon-Geul

    2018-03-01

    In this study, a new mathematical model of crawler cranes is developed for heavy working conditions, with payload-lifting and boom-hoisting motions simultaneously activated. The system model is built with full consideration of wind disturbances, geometrical nonlinearities, and cable elasticities of cargo lifting and boom luffing. On the basis of this dynamic model, three versions of sliding mode control are analyzed and designed to control five system outputs with only two inputs. When used in complicated operations, the effectiveness of the controllers is analyzed using analytical investigation and numerical simulation. Results indicate the effectiveness of the control algorithms and the proposed dynamic model. The control algorithms asymptotically stabilize the system with finite-time convergences, remaining robust amid disturbances and parametric uncertainties.

  10. Short-Term City Electric Load Forecasting with Considering Temperature Effects: An Improved ARIMAX Model

    Directory of Open Access Journals (Sweden)

    Herui Cui

    2015-01-01

    Full Text Available Short-term electric load is significantly affected by weather, especially the temperature effects in summer. External factors can result in mutation structures in load data. Under the influence of the external temperature factors, city electric load cannot be easily forecasted as usual. This research analyzes the relationship between electricity load and daily temperature in city. An improved ARIMAX model is proposed in this paper to deal with the mutation data structures. It is found that information amount of the improved ARIMAX model is smaller than that of the classic method and its relative error is less than AR, ARMA and Sigmoid-Function ANN models. The forecasting results are more accurately fitted. This improved model is highly valuable when dealing with mutation data structure in the field of load forecasting. And it is also an effective technique in forecasting electric load with temperature effects.

  11. A new coupled map car-following model considering drivers' steady desired speed

    International Nuclear Information System (INIS)

    Zhou Tong; Sun Di-Hua; Li Hua-Min; Liu Wei-Ning

    2014-01-01

    Based on the pioneering work of Konishi et al., in consideration of the influence of drivers' steady desired speed effect on the traffic flow, we develop a new coupled map car-following model in the real world. By use of the control theory, the stability condition of our model is derived. The validity of the present theoretical scheme is verified via numerical simulation, confirming the correctness of our theoretical analysis. (general)

  12. Modelling of an industrial NGL-Recovery unit considering environmental and economic impacts

    International Nuclear Information System (INIS)

    Sharratt, P. N.; Hernandez-Enriquez, A.; Flores-Tlacuahuac, A.

    2009-01-01

    In this work, an integrated model is presented that identifies key areas in the operation of a cryogenic NGL-recovery unit. This methodology sets out to provide deep understanding of various interrelationship across multiple plant operating factors including reliability, which could be essential for substantial improvement of process performance. The integrated model has been developed to predict the economic and environmental impacts of a real cryogenic unit (600 MMCUF/D) during normal operation, and has been built in Aspen TM. (Author)

  13. System dynamics approach for modeling of sugar beet yield considering the effects of climatic variables.

    Science.gov (United States)

    Pervin, Lia; Islam, Md Saiful

    2015-02-01

    The aim of this study was to develop a system dynamics model for computation of yields and to investigate the dependency of yields on some major climatic parameters, i.e. temperature and rainfall, for Beta vulgaris subsp. (sugar beet crops) under future climate change scenarios. A system dynamics model was developed which takes account of the effects of rainfall and temperature on sugar beet yields under limited irrigation conditions. A relationship was also developed between the seasonal evapotranspiration and seasonal growing degree days for sugar beet crops. The proposed model was set to run for the present time period of 1993-2012 and for the future period 2013-2040 for Lethbridge region (Alberta, Canada). The model provides sugar beet yields on a yearly basis which are comparable to the present field data. It was found that the future average yield will be increased at about 14% with respect to the present average yield. The proposed model can help to improve the understanding of soil water conditions and irrigation water requirements of an area under certain climatic conditions and can be used for future prediction of yields for any crops in any region (with the required information to be provided). The developed system dynamics model can be used as a supporting tool for decision making, for improvement of agricultural management practice of any region. © 2014 Society of Chemical Industry.

  14. New Elements To Consider When Modeling the Hazards Associated with Botulinum Neurotoxin in Food.

    Science.gov (United States)

    Ihekwaba, Adaoha E C; Mura, Ivan; Malakar, Pradeep K; Walshaw, John; Peck, Michael W; Barker, G C

    2016-01-15

    Botulinum neurotoxins (BoNTs) produced by the anaerobic bacterium Clostridium botulinum are the most potent biological substances known to mankind. BoNTs are the agents responsible for botulism, a rare condition affecting the neuromuscular junction and causing a spectrum of diseases ranging from mild cranial nerve palsies to acute respiratory failure and death. BoNTs are a potential biowarfare threat and a public health hazard, since outbreaks of foodborne botulism are caused by the ingestion of preformed BoNTs in food. Currently, mathematical models relating to the hazards associated with C. botulinum, which are largely empirical, make major contributions to botulinum risk assessment. Evaluated using statistical techniques, these models simulate the response of the bacterium to environmental conditions. Though empirical models have been successfully incorporated into risk assessments to support food safety decision making, this process includes significant uncertainties so that relevant decision making is frequently conservative and inflexible. Progression involves encoding into the models cellular processes at a molecular level, especially the details of the genetic and molecular machinery. This addition drives the connection between biological mechanisms and botulism risk assessment and hazard management strategies. This review brings together elements currently described in the literature that will be useful in building quantitative models of C. botulinum neurotoxin production. Subsequently, it outlines how the established form of modeling could be extended to include these new elements. Ultimately, this can offer further contributions to risk assessments to support food safety decision making. Copyright © 2015 Ihekwaba et al.

  15. Mathematical model of the loan portfolio dynamics in the form of Markov chain considering the process of new customers attraction

    Science.gov (United States)

    Bozhalkina, Yana

    2017-12-01

    Mathematical model of the loan portfolio structure change in the form of Markov chain is explored. This model considers in one scheme both the process of customers attraction, their selection based on the credit score, and loans repayment. The model describes the structure and volume of the loan portfolio dynamics, which allows to make medium-term forecasts of profitability and risk. Within the model corrective actions of bank management in order to increase lending volumes or to reduce the risk are formalized.

  16. Evaluation of energy efficiency in street lighting: model proposition considering climate variability

    Directory of Open Access Journals (Sweden)

    Amaury Caruzzo

    2015-12-01

    Full Text Available This paper assesses the impacts of climate variability on efficient electricity consumption in street lighting in Brazil. The Climate Demand Method (CDM was applied, and the energy savings achieved by Brazil’s National Efficient Street Lighting Program (ReLuz in 2005 were calculated, considering the monthly climatology of sunshine duration, disaggregated by county in Brazil. The total energy savings in street lighting in 2005 were estimated at 63 GWh/year or 1.39% higher than the value determined by ReLuz/Eletrobrás and there was a 15 MW reduction in demand in Brazil, considering the nearly 393,000 points in ReLuz served in 2005. The results indicate that, besides the difference in latitude, climate variability in different county increases the daily usage of street lighting up to 19%. Furthermore, Brazil’s large size means that seasonality patterns in energy savings are not homogeneous, and there is a correlation between the monthly variability in sunshine duration and the latitude of mesoregions. The CDM was also shown to be suitable for ranking mesoregions with the highest levels of energy saving lighting.

  17. Multiagent Model for Wide-Area Disaster-Evacuation Simulations with Local Factors Considered

    Science.gov (United States)

    Muraki, Yuji; Kanoh, Hitoshi

    In this paper, we propose a multiagent model for wide-area disaster-evacuation simulations with local factorsconsidered. Conventional multiagent models for evacuation simulations neither allow general-purpose computers to executewide-area simulations nor allow the object area to be changed easily. If these problems are solved, however, these simulations can be useful for local governments to make disaster damage prevention plan. In the proposed model, each roadis expressed by a series of cells. A computational amount relevant to interaction among agents is reduced by describing themodel for agents to be affected by other agents through the state of each cell. This makes possible wide area simulations. Using the data of a digital map database that is widely used for car navigation systems enables the simulations to beperformed for any region in Japan. Local factors are reflected in simulations by setting some parameters for evacuees, anevacuation environment, and disaster damage prevention plan of the object area. As an evaluation experiment, wesimulated the situations of Kobe city on the date of the Great Hanshin-Awaji Earthquake. Simulations results about thepercentage of evacuees who arrived at refuges were in good agreement with the actual data when parameters forevacuation-start timing were adjusted. We also simulated the current situations of two cities, Kobe and Tsukuba, and confirmed that this model was successfully applied to the two cities. From these evaluation experiments, we believe thatthis model can be applied to various areas and will perform further experiments in the future.

  18. Effects of task autonomy on performance: an extended model considering motivational, informational, and structural mechanisms.

    Science.gov (United States)

    Langfred, Claus W; Moye, Neta A

    2004-12-01

    A model explaining the relationship between task autonomy and performance is proposed that incorporates 3 different causal mechanisms. The performance benefits of task autonomy may be realized by increased motivation (motivational mechanisms), by capitalization of information asymmetries (informational mechanisms), or by better alignment with task and organizational structures (structural mechanisms). Further, it is proposed that these performance benefits are moderated by a variety of variables ranging from individual traits to organizational design. This model may provide a means for accounting for the sometimes inconsistent findings in the empirical literature exploring the relationship between autonomy and performance. The model also offers guidance in the search for additional boundary conditions as well as prescriptive guidelines for the allocation of autonomy in practice. 2004 APA, all rights reserved

  19. An Integer Programming Model for Multi-Echelon Supply Chain Decision Problem Considering Inventories

    Science.gov (United States)

    Harahap, Amin; Mawengkang, Herman; Siswadi; Effendi, Syahril

    2018-01-01

    In this paper we address a problem that is of significance to the industry, namely the optimal decision of a multi-echelon supply chain and the associated inventory systems. By using the guaranteed service approach to model the multi-echelon inventory system, we develop a mixed integer; programming model to simultaneously optimize the transportation, inventory and network structure of a multi-echelon supply chain. To solve the model we develop a direct search approach using a strategy of releasing nonbasic variables from their bounds, combined with the “active constraint” method. This strategy is used to force the appropriate non-integer basic variables to move to their neighbourhood integer points.

  20. Hot Deformation Behavior and Constitutive Modeling of Alloy 800H Considering Effectsof Strain

    Science.gov (United States)

    Luo, Rui; Zheng, Qi; Tang, Zhending; Yao, Yongquan; Xu, Guifang; Li, Dongsheng; Cheng, Xiaonong

    2017-05-01

    High-temperature single-pass compression experiments were conducted on alloy 800H using a Gleeble 3500 thermal-mechanical simulation testing machine, and hot deformation behaviors at temperatures of 1,000-1,150 °C and strain rates of 0.01-1 s-1 were investigated. The results revealed that dynamic recrystallization (DRX) behavior occurred more easily under deformation conditions with relatively low strain rates and high deformation temperatures. By taking the influence of strain on the hot deformation behavior into consideration, a strain-dependent hyperbolic sine constitutive model was constructed. Based on this revised constitutive model, flow stress during deformation was predicted. The linear relation between the predicted value and the experimental result was as high as 0.99648, and the absolute average relative error was 2.019 %. Thus, it was demonstrated that the strain-dependent analysis provided a constitutive model that was able to precisely predict flow stress under experimental conditions.

  1. Mixed integer linear programming model for dynamic supplier selection problem considering discounts

    Directory of Open Access Journals (Sweden)

    Adi Wicaksono Purnawan

    2018-01-01

    Full Text Available Supplier selection is one of the most important elements in supply chain management. This function involves evaluation of many factors such as, material costs, transportation costs, quality, delays, supplier capacity, storage capacity and others. Each of these factors varies with time, therefore, supplier identified for one period is not necessarily be same for the next period to supply the same product. So, mixed integer linear programming (MILP was developed to overcome the dynamic supplier selection problem (DSSP. In this paper, a mixed integer linear programming model is built to solve the lot-sizing problem with multiple suppliers, multiple periods, multiple products and quantity discounts. The buyer has to make a decision for some products which will be supplied by some suppliers for some periods cosidering by discount. To validate the MILP model with randomly generated data. The model is solved by Lingo 16.

  2. Potential of Winkler type platform models for SSI problems considering flexibility of base mat

    International Nuclear Information System (INIS)

    Tyapin, Alexander

    2013-01-01

    Highlights: • Base mat's flexibility affects different seismic response parameters in different ways. • The most sensitive are the internal seismic response forces in the base mat itself. • Vertical response accelerations in the centers of the rooms are sensitive too. • Shaped Winkler model generally gives better results than the conventional flat one. • Even shaped Winkler model cannot reproduce the response in two sensitive formats. -- Abstract: Linear soil-structure interaction (SSI) analysis seems to be well understood nowadays and can be performed, for example, by convenient combined asymptotic method (CAM). However, CAM is asymptotically accurate for rigid base mats only – this is a limitation. So, the additional research is needed to find out (a) what is the impact of the base mat's flexibility to the seismic response; (b) how can one account for this impact using the conventional tools. In the first part of the paper a sample “wave” solution is obtained in the frequency domain using SASSI2000 code, without CAM at all. Different formats of the seismic response (e.g., in-structure response spectra, soil-structure interaction forces, in-structure internal forces) have proved to have different sensitivity to the base mat's flexibility. In the second part of the paper this wave solution is a benchmark for the different “platform” models with “soil” springs and dashpots distributed over the base mat (this is a broad definition of Winkler type model). Different shapes of distribution, starting from the conventional Winkler's flat shape and up to the “optimal” shape, are compared to each other in the second part of the paper. It is shown that even the most advanced “shaped” models of the Winkler type are limited in their ability to reproduce seismic response in the most sensitive format – the internal forces in the mat. This is the result of (a) local nature of Winkler's model, and (b) frequency independence of its’ parameters

  3. Light Path Model of Fiber Optic Liquid Level Sensor Considering Residual Liquid Film on the Wall

    Directory of Open Access Journals (Sweden)

    Zhijun Zhang

    2015-01-01

    Full Text Available The working principle of the refractive-type fiber optic liquid level sensor is analyzed in detail based on the light refraction principle. The optic path models are developed in consideration of common simplification and the residual liquid film on the glass tube wall. The calculating formulae for the model are derived, constraint conditions are obtained, influencing factors are discussed, and the scopes and skills of application are analyzed through instance simulations. The research results are useful in directing the correct usage of the fiber optic liquid level sensor, especially in special cases, such as those involving viscous liquid in the glass tube monitoring.

  4. Improved dq-axes Model of PMSM Considering Airgap Flux Harmonics and Saturation

    DEFF Research Database (Denmark)

    Fasil, Muhammed; Antaloae, Ciprian; Mijatovic, Nenad

    along with magnet torque, the accuracy of linear models are found to be insufficient. In this work, the effect of air gap flux harmonics is included in the classical model of PMSM using d and q-axes harmonic inductances. Further, a method has been presented to assess the effect of saturation and cross......-saturation on constant torque curves of PMSM. Two interior permanent magnet motor with two different rotor topologies and different specifications are designed to evaluate the effect of saturation on synchronous and harmonic inductances, and operating points of the machines....

  5. A Duopoly Manufacturers’ Game Model Considering Green Technology Investment under a Cap-and-Trade System

    Directory of Open Access Journals (Sweden)

    Yi Zheng

    2018-03-01

    Full Text Available This research studied the duopoly manufacturers’ decision-making considering green technology investment and under a cap-and-trade system. It was assumed there were two manufacturers producing products which were substitutable for one another. On the basis of this assumption, the optimal production capacity, price, and green technology investment of the duopoly manufacturers under a cap-and-trade system were obtained. The increase or decrease of the optimal production quantity of the duopoly manufacturers under a cap-and-trade system was decided by their green technology level. The increase of the optimal price as well as the increase or decrease of the maximum expected profits were decided by the initial carbon emission quota granted by the government. Our research indicates that the carbon emission of unit product is inversely proportional to the market share of an enterprise and becomes an important index to measure the core competitiveness of an enterprise.

  6. Rumor spreading model considering forgetting and remembering mechanisms in inhomogeneous networks

    Science.gov (United States)

    Zhao, Laijun; Qiu, Xiaoyan; Wang, Xiaoli; Wang, Jiajia

    2013-02-01

    The SIHR rumor spreading model with consideration of the forgetting and remembering mechanisms was studied in homogeneous networks. We further investigate the properties of the SIHR model in inhomogeneous networks. The SIHR model is refined and mean-field equations are derived to describe the dynamics of the rumor spreading model in inhomogeneous networks. Steady-state analysis is carried out, which shows no spreading threshold existing. Numerical simulations are conducted in a BA scale-free network. The simulation results show that the network topology exerts significant influences on the rumor spreading: In comparison with the ER network, the rumor spreads faster and the final size of the rumor is smaller in BA scale-free network; the forgetting and remembering mechanisms greatly impact the final size of the rumor. Finally, through the numerical simulation, we examine the effects that the spreading rate and the stifling rate have on the the influence of the rumor. In addition, the no threshold result is verified.

  7. Transcriptomic analysis in a Drosophila model identifies previously implicated and novel pathways in the therapeutic mechanism in neuropsychiatric disorders

    Directory of Open Access Journals (Sweden)

    Priyanka eSingh

    2011-03-01

    Full Text Available We have taken advantage of a newly described Drosophila model to gain insights into the potential mechanism of antiepileptic drugs (AEDs, a group of drugs that are widely used in the treatment of several neurological and psychiatric conditions besides epilepsy. In the recently described Drosophila model that is inspired by pentylenetetrazole (PTZ induced kindling epileptogenesis in rodents, chronic PTZ treatment for seven days causes a decreased climbing speed and an altered CNS transcriptome, with the latter mimicking gene expression alterations reported in epileptogenesis. In the model, an increased climbing speed is further observed seven days after withdrawal from chronic PTZ. We used this post-PTZ withdrawal regime to identify potential AED mechanism. In this regime, treatment with each of the five AEDs tested, namely, ethosuximide (ETH, gabapentin (GBP, vigabatrin (VGB, sodium valproate (NaVP and levetiracetam (LEV, resulted in rescuing of the altered climbing behavior. The AEDs also normalized PTZ withdrawal induced transcriptomic perturbation in fly heads; whereas AED untreated flies showed a large number of up- and down-regulated genes which were enriched in several processes including gene expression and cell communication, the AED treated flies showed differential expression of only a small number of genes that did not enrich gene expression and cell communication processes. Gene expression and cell communication related upregulated genes in AED untreated flies overrepresented several pathways - spliceosome, RNA degradation, and ribosome in the former category, and inositol phosphate metabolism, phosphatidylinositol signaling, endocytosis and hedgehog signaling in the latter. Transcriptome remodeling effect of AEDs was overall confirmed by microarray clustering that clearly separated the profiles of AED treated and untreated flies. Besides being consistent with previously implicated pathways, our results provide evidence for a role of

  8. Potential of Winkler type platform models for SSI problems considering flexibility of base mat

    Energy Technology Data Exchange (ETDEWEB)

    Tyapin, Alexander, E-mail: Atyapin@bvcp.ru

    2013-10-15

    Highlights: • Base mat's flexibility affects different seismic response parameters in different ways. • The most sensitive are the internal seismic response forces in the base mat itself. • Vertical response accelerations in the centers of the rooms are sensitive too. • Shaped Winkler model generally gives better results than the conventional flat one. • Even shaped Winkler model cannot reproduce the response in two sensitive formats. -- Abstract: Linear soil-structure interaction (SSI) analysis seems to be well understood nowadays and can be performed, for example, by convenient combined asymptotic method (CAM). However, CAM is asymptotically accurate for rigid base mats only – this is a limitation. So, the additional research is needed to find out (a) what is the impact of the base mat's flexibility to the seismic response; (b) how can one account for this impact using the conventional tools. In the first part of the paper a sample “wave” solution is obtained in the frequency domain using SASSI2000 code, without CAM at all. Different formats of the seismic response (e.g., in-structure response spectra, soil-structure interaction forces, in-structure internal forces) have proved to have different sensitivity to the base mat's flexibility. In the second part of the paper this wave solution is a benchmark for the different “platform” models with “soil” springs and dashpots distributed over the base mat (this is a broad definition of Winkler type model). Different shapes of distribution, starting from the conventional Winkler's flat shape and up to the “optimal” shape, are compared to each other in the second part of the paper. It is shown that even the most advanced “shaped” models of the Winkler type are limited in their ability to reproduce seismic response in the most sensitive format – the internal forces in the mat. This is the result of (a) local nature of Winkler's model, and (b) frequency

  9. An extended car-following model considering random safety distance with different probabilities

    Science.gov (United States)

    Wang, Jufeng; Sun, Fengxin; Cheng, Rongjun; Ge, Hongxia; Wei, Qi

    2018-02-01

    Because of the difference in vehicle type or driving skill, the driving strategy is not exactly the same. The driving speeds of the different vehicles may be different for the same headway. Since the optimal velocity function is just determined by the safety distance besides the maximum velocity and headway, an extended car-following model accounting for random safety distance with different probabilities is proposed in this paper. The linear stable condition for this extended traffic model is obtained by using linear stability theory. Numerical simulations are carried out to explore the complex phenomenon resulting from multiple safety distance in the optimal velocity function. The cases of multiple types of safety distances selected with different probabilities are presented. Numerical results show that the traffic flow with multiple safety distances with different probabilities will be more unstable than that with single type of safety distance, and will result in more stop-and-go phenomena.

  10. Expanding the Role of Systems Modeling: Considering Byproduct Generation from Biofuel Production

    Directory of Open Access Journals (Sweden)

    Kurt A. Rosentrater

    2006-06-01

    Full Text Available The bioethanol industry has been experiencing rapid growth over the past several years, and is expected to continue to increase production for the foreseeable future. A vital component to the success of this industry is the sales and marketing of processing residues, which are primarily sold as dried distillers grains with solubles (DDGS. Systems modeling, a technique that has been used to predict future demand for bioethanol, can also be used to determine potential byproduct generation rates. This paper discusses the development of one such model, and presents predicted generation of DDGS as well as carbon dioxide emissions from this industry through 2100. These simulation results underscore the growing need to actively pursue research focused on value-added alternatives for the use of bioethanol byproduct streams.

  11. Air-gun signature modelling considering the influence of mechanical structure factors

    Science.gov (United States)

    Li, Guofa; Liu, Zhao; Wang, Jianhua; Cao, Mingqiang

    2014-04-01

    In marine seismic prospecting, as the air-gun array is usually composed of different types of air-guns, the signature modelling of different air-guns is particularly important to the array design. Different types of air-guns have different mechanical structures, which directly or indirectly affect the signatures. In order to simulate the influence of the mechanical structure, five parameters—the throttling constant, throttling power law exponent, mass release efficiency, fluid viscosity and heat transfer coefficient—are used in signature modelling. Through minimizing the energy relative error between the simulated and the measured signatures by the simulated annealing method, the five optimal parameters can be estimated. The method is tested in a field experiment, and the consistency between the simulated and the measured signatures is improved with the optimal parameters.

  12. Evaluation of the maximum loadability point of power systems considering the effect of static load models

    International Nuclear Information System (INIS)

    Amjady, Nima; Velayati, Mohammad Hossein

    2009-01-01

    Power system stability is an important problem for power system operation. Determination of different stability margins can result in the optimum utilization of power system with minimum risk. Voltage stability is an important subset of power system stability. To correctly analyze the voltage stability of a power system, suitable dynamic models are usually required. However, static analysis tools can give us useful information about long term voltage stability. Especially, maximum loadability point (MLP) of a power system can be effectively estimated by modal analysis of load flow Jacobians. MLP is one of the important boundaries of voltage stability feasible region that loading beyond which is of little practical meaning. In this paper, MLP boundary of power system is analyzed by means of static analysis tools and its differences with the other boundaries of voltage stability, like saddle node bifurcation, are discussed. Effect of reactive power limits of generators and different static load models on the MLP border is also evaluated.

  13. Energy cost models for air supported sports hall in cold climates considering energy efficiency

    OpenAIRE

    Nord, Natasa; Mathisen, Hans Martin; Cao, Guangyu

    2015-01-01

    The aim of the study was to develop models for energy planning for an air supported sports hall by analyzing different energy efficiency possibilities. This is a very specific building type suitable for sport activities in cold climates. The observed hall was operated when outdoor temperature was under 5 °C, while the most common measured indoor air temperature was 8 °C during the year. Neither indoor nor outdoor temperature influenced the overpressure. Based on the measurements, the specific...

  14. A Three-Phase Microgrid Restoration Model Considering Unbalanced Operation of Distributed Generation

    International Nuclear Information System (INIS)

    Wang, Zeyu; Wang, Jianhui; Chen, Chen

    2016-01-01

    Recent severe outages highlight the urgency of improving grid resiliency in the U.S. Microgrid formation schemes are proposed to restore critical loads after outages occur. Most distribution networks have unbalanced configurations that are not represented in sufficient detail by single-phase models. This study provides a microgrid formation plan that adopts a three-phase network model to represent unbalanced distribution networks. The problem formulation has a quadratic objective function with mixed-integer linear constraints. The three-phase network model enables us to examine the three-phase power outputs of distributed generators (DGs), preventing unbalanced operation that might trip DGs. Because the DG unbalanced operation constraint is non-convex, an iterative process is presented that checks whether the unbalanced operation limits for DGs are satisfied after each iteration of optimization. We also develop a relatively conservative linear approximation on the unbalanced operation constraint to handle larger networks. Compared with the iterative solution process, the conservative linear approximation is able to accelerate the solution process at the cost of sacrificing optimality to a limited extent. Simulation in the IEEE 34 node and IEEE 123 test feeders indicate that the proposed method yields more practical microgrid formations results. In addition, this paper explores the coordinated operation of DGs and energy storage (ES) installations. The unbalanced three-phase outputs of ESs combined with the relatively balanced outputs of DGs could supply unbalanced loads. In conclusion, the case study also validates the DG-ES coordination.

  15. A Two-Stage Queue Model to Optimize Layout of Urban Drainage System considering Extreme Rainstorms

    Directory of Open Access Journals (Sweden)

    Xinhua He

    2017-01-01

    Full Text Available Extreme rainstorm is a main factor to cause urban floods when urban drainage system cannot discharge stormwater successfully. This paper investigates distribution feature of rainstorms and draining process of urban drainage systems and uses a two-stage single-counter queue method M/M/1→M/D/1 to model urban drainage system. The model emphasizes randomness of extreme rainstorms, fuzziness of draining process, and construction and operation cost of drainage system. Its two objectives are total cost of construction and operation and overall sojourn time of stormwater. An improved genetic algorithm is redesigned to solve this complex nondeterministic problem, which incorporates with stochastic and fuzzy characteristics in whole drainage process. A numerical example in Shanghai illustrates how to implement the model, and comparisons with alternative algorithms show its performance in computational flexibility and efficiency. Discussions on sensitivity of four main parameters, that is, quantity of pump stations, drainage pipe diameter, rainstorm precipitation intensity, and confidence levels, are also presented to provide guidance for designing urban drainage system.

  16. The Unsaturated Hydromechanical Coupling Model of Rock Slope Considering Rainfall Infiltration Using DDA

    Directory of Open Access Journals (Sweden)

    Xianshan Liu

    2017-01-01

    Full Text Available Water flow and hydromechanical coupling process in fractured rocks is more different from that in general porous media because of heterogeneous spatial fractures and possible fracture-dominated flow; a saturated-unsaturated hydromechanical coupling model using a discontinuous deformation analysis (DDA similar to FEM and DEM was employed to analyze water movement in saturated-unsaturated deformed rocks, in which the Van-Genuchten model differently treated the rock and fractures permeable properties to describe the constitutive relationships. The calibrating results for the dam foundation indicated the validation and feasibility of the proposed model and are also in good agreement with the calculations based on DEM still demonstrating its superiority. And then, the rainfall infiltration in a reservoir rock slope was detailedly investigated to describe the water pressure on the fault surface and inside the rocks, displacement, and stress distribution under hydromechanical coupling conditions and uncoupling conditions. It was observed that greater rainfall intensity and longer rainfall time resulted in lower stability of the rock slope, and larger difference was very obvious between the hydromechanical coupling condition and uncoupling condition, demonstrating that rainfall intensity, rainfall time, and hydromechanical coupling effect had great influence on the saturated-unsaturated water flow behavior and mechanical response of the fractured rock slopes.

  17. Considering Decision Variable Diversity in Multi-Objective Optimization: Application in Hydrologic Model Calibration

    Science.gov (United States)

    Sahraei, S.; Asadzadeh, M.

    2017-12-01

    Any modern multi-objective global optimization algorithm should be able to archive a well-distributed set of solutions. While the solution diversity in the objective space has been explored extensively in the literature, little attention has been given to the solution diversity in the decision space. Selection metrics such as the hypervolume contribution and crowding distance calculated in the objective space would guide the search toward solutions that are well-distributed across the objective space. In this study, the diversity of solutions in the decision-space is used as the main selection criteria beside the dominance check in multi-objective optimization. To this end, currently archived solutions are clustered in the decision space and the ones in less crowded clusters are given more chance to be selected for generating new solution. The proposed approach is first tested on benchmark mathematical test problems. Second, it is applied to a hydrologic model calibration problem with more than three objective functions. Results show that the chance of finding more sparse set of high-quality solutions increases, and therefore the analyst would receive a well-diverse set of options with maximum amount of information. Pareto Archived-Dynamically Dimensioned Search, which is an efficient and parsimonious multi-objective optimization algorithm for model calibration, is utilized in this study.

  18. Nonlinear Finite Element Modelling of Railway Turnout System considering Bearer/Sleeper-Ballast Interaction

    Directory of Open Access Journals (Sweden)

    James Sae Siew

    2015-01-01

    Full Text Available Rail turnouts are built to enable flexibility in the rail network as they allow for vehicles to switch between various tracks, therefore maximizing the utilisation of existing rail infrastructure. In general, railway turnouts are a safety-critical and expensive feature to a rail system as they suffer aggressive operational loads, in comparison to a plain rail track, and thus require frequent monitoring and maintenance. In practice, great consideration is given to the dynamic interaction between the turnouts components as a failed component may have adverse effects on the performance of neighbouring components. This paper presents a nonlinear 3D finite element (FE model, taking into account the nonlinearities of materials, in order to evaluate the interaction and behaviour of turnout components. Using ABAQUS, the finite element model was developed to simulate standard concrete bearers with 60 kg/m rail and with a tangential turnout radius of 250 m. The turnout structure is supported by a ballast layer, which is represented by a nonlinearly deformable tensionless solid. The numerical studies firstly demonstrate the importance of load transfer mechanisms in the failure modes of the turnout components. The outcome will lead to a better design and maintenance of railway turnouts, improving public safety and operational reliability.

  19. Analysis of HD Journal Bearings Considering Elastic Deformation and Non-Newtonian Rabinowitsch Fluid Model

    Directory of Open Access Journals (Sweden)

    J. Javorova

    2016-06-01

    Full Text Available The purpose of this paper is to study the performance of a finite length journal bearing, taking into account effects of non-Newtonian Rabinowitsch flow rheology and elastic deformations of the bearing liner. According to the Rabinowitsch fluid model, the cubic-stress constitutive equation is used to account for the non-Newtonian effects of pseudoplastic and dilatant lubricants. Integrating the continuity equation across the film, the nonlinear non-Newtonian Reynolds-type equation is derived. The elasticity part of the problem is solved on the base of Vlassov model of an elastic foundation. The numerical solution of the modified Reynolds equation is carried out by using FDM with over-relaxation technique. The results for steady state bearing performance characteristics have been calculated for various values of nonlinear factor and elasticity parameters. It was concluded that in comparison with the Newtonian lubricants, higher values of film pressure and load carrying capacity have been obtained for dilatant lubricants, while the case was reversed for pseudoplastic lubricants.

  20. A novel rumor diffusion model considering the effect of truth in online social media

    Science.gov (United States)

    Sun, Ling; Liu, Yun; Zeng, Qing-An; Xiong, Fei

    2015-12-01

    In this paper, we propose a model to investigate how truth affects rumor diffusion in online social media. Our model reveals a relation between rumor and truth — namely, when a rumor is diffusing, the truth about the rumor also diffuses with it. Two patterns of the agents used to identify rumor, self-identification and passive learning are taken into account. Combining theoretical proof and simulation analysis, we find that the threshold value of rumor diffusion is negatively correlated to the connectivity between nodes in the network and the probability β of agents knowing truth. Increasing β can reduce the maximum density of the rumor spreaders and slow down the generation speed of new rumor spreaders. On the other hand, we conclude that the best rumor diffusion strategy must balance the probability of forwarding rumor and the probability of agents losing interest in the rumor. High spread rate λ of rumor would lead to a surge in truth dissemination which will greatly limit the diffusion of rumor. Furthermore, in the case of unknown λ, increasing β can effectively reduce the maximum proportion of agents who do not know the truth, but cannot narrow the rumor diffusion range in a certain interval of β.

  1. A general electromagnetic excitation model for electrical machines considering the magnetic saturation and rub impact

    Science.gov (United States)

    Xu, Xueping; Han, Qinkai; Chu, Fulei

    2018-03-01

    The electromagnetic vibration of electrical machines with an eccentric rotor has been extensively investigated. However, magnetic saturation was often neglected. Moreover, the rub impact between the rotor and stator is inevitable when the amplitude of the rotor vibration exceeds the air-gap. This paper aims to propose a general electromagnetic excitation model for electrical machines. First, a general model which takes the magnetic saturation and rub impact into consideration is proposed and validated by the finite element method and reference. The dynamic equations of a Jeffcott rotor system with electromagnetic excitation and mass imbalance are presented. Then, the effects of pole-pair number and rubbing parameters on vibration amplitude are studied and approaches restraining the amplitude are put forward. Finally, the influences of mass eccentricity, resultant magnetomotive force (MMF), stiffness coefficient, damping coefficient, contact stiffness and friction coefficient on the stability of the rotor system are investigated through the Floquet theory, respectively. The amplitude jumping phenomenon is observed in a synchronous generator for different pole-pair numbers. The changes of design parameters can alter the stability states of the rotor system and the range of parameter values forms the zone of stability, which lays helpful suggestions for the design and application of the electrical machines.

  2. A Constitutive Model for Superelastic Shape Memory Alloys Considering the Influence of Strain Rate

    Directory of Open Access Journals (Sweden)

    Hui Qian

    2013-01-01

    Full Text Available Shape memory alloys (SMAs are a relatively new class of functional materials, exhibiting special thermomechanical behaviors, such as shape memory effect and superelasticity, which enable their applications in seismic engineering as energy dissipation devices. This paper investigates the properties of superelastic NiTi shape memory alloys, emphasizing the influence of strain rate on superelastic behavior under various strain amplitudes by cyclic tensile tests. A novel constitutive equation based on Graesser and Cozzarelli’s model is proposed to describe the strain-rate-dependent hysteretic behavior of superelastic SMAs at different strain levels. A stress variable including the influence of strain rate is introduced into Graesser and Cozzarelli’s model. To verify the effectiveness of the proposed constitutive equation, experiments on superelastic NiTi wires with different strain rates and strain levels are conducted. Numerical simulation results based on the proposed constitutive equation and experimental results are in good agreement. The findings in this paper will assist the future design of superelastic SMA-based energy dissipation devices for seismic protection of structures.

  3. Fatigue Modeling for Superelastic NiTi Considering Cyclic Deformation and Load Ratio Effects

    Science.gov (United States)

    Mahtabi, Mohammad J.; Shamsaei, Nima

    2017-09-01

    A cumulative energy-based damage model, called total fatigue toughness, is proposed for fatigue life prediction of superelastic NiTi alloys with various deformation responses (i.e., transformation stresses), which also accounts for the effects of mean strain and stress. Mechanical response of superelastic NiTi is highly sensitive to chemical composition, material processing, as well as operating temperature; therefore, significantly different deformation responses may be obtained for seemingly identical NiTi specimens. In this paper, a fatigue damage parameter is proposed that can be used for fatigue life prediction of superelastic NiTi alloys with different mechanical properties such as loading and unloading transformation stresses, modulus of elasticity, and austenite-to-martensite start and finish strains. Moreover, the model is capable of capturing the effects of tensile mean strain and stress on the fatigue behavior. Fatigue life predictions using the proposed damage parameter for specimens with different cyclic stress responses, tested at various strain ratios ( R ɛ = ɛ min /ɛ max) are shown to be in very good agreement with the experimentally observed fatigue lives.

  4. Evolving Model for the Complex Traffic and Transportation Network Considering Self-Growth Situation

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2012-01-01

    Full Text Available It has been approved that the scale-free feature exists in various complex networks, such as the internet, the cell or the biological networks. In order to analyze the influence of the self-growth phenomenon during the growth on the structure of traffic and transportation network, we formulated an evolving model. Based on the evolving model, we prove in mathematics that, even that the self-growth situation happened, the traffic and transportation network owns the scale-free feature due to that the node degree follows a power-law distribution. A real traffic and transportation network, China domestic airline network is tested to consolidate our conclusions. We find that the airline network has a node degree distribution equivalent to the power-law of which the estimated scaling parameter is about 3.0. Moreover the standard error of the estimated scaling parameter changes according to the self-growth probability. Our findings could provide useful information for determining the optimal structure or status of the traffic and transportation network.

  5. Analysis of car-following model considering driver’s physical delay in sensing headway

    Science.gov (United States)

    Zhu, H. B.; Dai, S. Q.

    2008-05-01

    An extended car-following model is proposed by taking into account the delay of the driver’s response in sensing headway. The stability condition of this model is obtained by using the linear stability theory. The results show that the stability region decreases when the driver’s physical delay in sensing headway increases. The KdV equation and mKdV equation near the neutral stability line and the critical point are respectively derived by applying the reductive perturbation method. The traffic jams could be thus described by soliton solution and kink-antikink soliton solution for the KdV equation and mKdV equation respectively. The numerical results in the form of the space-time evolution of headway show that the stabilization effect is weakened when the driver’s physical delay increases. It confirms the fact that the delay of driver’s response in sensing headway plays an important role in jamming transition, and the numerical results are in good agreement with the theoretical analysis.

  6. Numerical Modelling of Tailings Dam Thermal-Seepage Regime Considering Phase Transitions

    Directory of Open Access Journals (Sweden)

    Aniskin Nikolay Alekseevich

    2017-01-01

    Full Text Available Statement of the Problem. The article describes the problem of combined thermal-seepage regime for earth dams and those operated in the permafrost conditions. This problem can be solved using the finite elements method based on the local variational formulation. Results. A thermal-seepage regime numerical model has been developed for the “dam-foundation” system in terms of the tailings dam. The effect of heat-and-mass transfer and liquid phase transition in soil interstices on the dam state is estimated. The study with subsequent consideration of these factors has been undertaken. Conclusions. The results of studying the temperature-filtration conditions of the structure based on the factors of heat-and-mass transfer and liquid phase transition have shown that the calculation results comply with the field data. Ignoring these factors or one of them distorts the real situation of the dam thermal-seepage conditions.

  7. Decision Model for Planning and Scheduling of Seafood Product Considering Traceability

    Science.gov (United States)

    Agustin; Mawengkang, Herman; Mathelinea, Devy

    2018-01-01

    Due to the global challenges, it is necessary for an industrial company to integrate production scheduling and distribution planning, in order to be more efficient and to get more economics advantages. This paper presents seafood production planning and scheduling of a seafood manufacture company which produces simultaneously multi kind of seafood products, located at Aceh Province, Indonesia. The perishability nature of fish highly restricts its storage duration and delivery conditions. Traceability is a tracking requirement to check whether the quality of the product is satisfied. The production and distribution planning problem aims to meet customer demand subject to traceability of the seafood product and other restrictions. The problem is modeled as a mixed integer linear program, and then it is solved using neighborhood search approach.

  8. Improved ADM1 model for anaerobic digestion process considering physico-chemical reactions.

    Science.gov (United States)

    Zhang, Yang; Piccard, Sarah; Zhou, Wen

    2015-11-01

    The "Anaerobic Digestion Model No. 1" (ADM1) was modified in the study by improving the bio-chemical framework and integrating a more detailed physico-chemical framework. Inorganic carbon and nitrogen balance terms were introduced to resolve the discrepancies in the original bio-chemical framework between the carbon and nitrogen contents in the degraders and substrates. More inorganic components and solids precipitation processes were included in the physico-chemical framework of ADM1. The modified ADM1 was validated with the experimental data and used to investigate the effects of calcium ions, magnesium ions, inorganic phosphorus and inorganic nitrogen on anaerobic digestion in batch reactor. It was found that the entire anaerobic digestion process might exist an optimal initial concentration of inorganic nitrogen for methane gas production in the presence of calcium ions, magnesium ions and inorganic phosphorus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Modeling and Experimental Tests of a Mechatronic Device to Measure Road Profiles Considering Impact Dynamics

    DEFF Research Database (Denmark)

    Souza, A.; Santos, Ilmar

    2002-01-01

    to highlight that the aim of this device is to independently measure two road profiles, without the influence of the vehicle dynamics where the mechanism is attached. Before the mechatronic mechanism is attached to a real vehicle, its dynamic behavior must be known. A theoretical analysis of the mechanism......Vehicles travel at different speeds and, as a consequence, experience a broad spectrum of vibrations. One of the most important source of vehicle vibration is the road profile. Hence the knowledge of the characteristics of a road profile enables engineers to predict the dynamic behavior...... dynamics is led with help of a set of non-linear equations of motion obtained using Newton-Euler-Jourdain´s Method. Such a set of equation is numerically solved and the theoretical results are compared with experimental carried out with a laboratory prototype. Comparisons show that the theoretical model...

  10. Model of refrigerated display-space allocation for multi agro-perishable products considering markdown policy

    Science.gov (United States)

    Satiti, D.; Rusdiansyah, A.

    2018-04-01

    Problems that need more attention in the agri-food supply chain are loss and waste as consequences from improper quality control and excessive inventories. The use of cold storage is still being one of favourite technologies in controlling product quality by majority of retailers. We considerate the temperature of cold storage in determining the inventory and pricing strategies based on identified product quality. This study aims to minimize the agri-food waste, utility of cold storage facilities and maximize retailer’s profit through determining the refrigerated display-space allocation and markdown policy based on identified food shelf life. The proposed model evaluated with several different scenarios to find out the right strategy.

  11. Modeling Travel Time Reliability of Road Network Considering Connected Vehicle Guidance Characteristics Indexes

    Directory of Open Access Journals (Sweden)

    Jiangfeng Wang

    2017-01-01

    Full Text Available Travel time reliability (TTR is one of the important indexes for effectively evaluating the performance of road network, and TTR can effectively be improved using the real-time traffic guidance information. Compared with traditional traffic guidance, connected vehicle (CV guidance can provide travelers with more timely and accurate travel information, which can further improve the travel efficiency of road network. Five CV characteristics indexes are selected as explanatory variables including the Congestion Level (CL, Penetration Rate (PR, Compliance Rate (CR, release Delay Time (DT, and Following Rate (FR. Based on the five explanatory variables, a TTR model is proposed using the multilogistic regression method, and the prediction accuracy and the impact of characteristics indexes on TTR are analyzed using a CV guidance scenario. The simulation results indicate that 80% of the RMSE is concentrated within the interval of 0 to 0.0412. The correlation analysis of characteristics indexes shows that the influence of CL, PR, CR, and DT on the TTR is significant. PR and CR have a positive effect on TTR, and the average improvement rate is about 77.03% and 73.20% with the increase of PR and CR, respectively, while CL and DT have a negative effect on TTR, and TTR decreases by 31.21% with the increase of DT from 0 to 180 s.

  12. Considering an integrated nephrology care delivery model: six principles for quality.

    Science.gov (United States)

    Hamm, L Lee; Hostetter, Thomas H; Shaffer, Rachel N

    2013-04-01

    In 2012, 27 organizations will initiate participation in the Medicare Shared Savings Program as Accountable Care Organizations. This level of participation reflects the response of Centers for Medicare and Medicaid Services to criticism that the program as outlined in the proposed rule was overly burdensome, prescriptive, and too risky. Centers for Medicare and Medicaid Service made significant changes in the final rule, making the Accountable Care Organization program more attractive to these participants. However, none of these changes addressed the serious concerns raised by subspecialty societies-including the American Society of Nephrology-regarding care of patients with multiple chronic comorbidities and complex and end stage conditions. Virtually all of these concerns remain unaddressed, and consequently, Accountable Care Organizations will require guidance and partnership from the nephrology community to ensure that these patients are identified and receive the individualized care that they require. Although the final rule fell short of addressing the needs of patients with kidney disease, the Centers for Medicare and Medicaid Innovation presents an opportunity to test the potentially beneficial concepts of the Accountable Care Organization program within this patient population. The American Society of Nephrology Accountable Care Organization Task Force developed a set of principles that must be reflected in a possible pilot program or demonstration project of an integrated nephrology care delivery model. These principles include preserving a leadership role for nephrologists, encompassing care for patients with later-stage CKD and kidney transplants as well as ESRD, enabling the participation of a diversity of dialysis provider sizes and types, facilitating research, and establishing monitoring systems to identify and address preferential patient selection or changes in outcomes.

  13. Interpreting "Personality" Taxonomies: Why Previous Models Cannot Capture Individual-Specific Experiencing, Behaviour, Functioning and Development. Major Taxonomic Tasks Still Lay Ahead.

    Science.gov (United States)

    Uher, Jana

    2015-12-01

    As science seeks to make generalisations, a science of individual peculiarities encounters intricate challenges. This article explores these challenges by applying the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) and by exploring taxonomic "personality" research as an example. Analyses of researchers' interpretations of the taxonomic "personality" models, constructs and data that have been generated in the field reveal widespread erroneous assumptions about the abilities of previous methodologies to appropriately represent individual-specificity in the targeted phenomena. These assumptions, rooted in everyday thinking, fail to consider that individual-specificity and others' minds cannot be directly perceived, that abstract descriptions cannot serve as causal explanations, that between-individual structures cannot be isomorphic to within-individual structures, and that knowledge of compositional structures cannot explain the process structures of their functioning and development. These erroneous assumptions and serious methodological deficiencies in widely used standardised questionnaires have effectively prevented psychologists from establishing taxonomies that can comprehensively model individual-specificity in most of the kinds of phenomena explored as "personality", especially in experiencing and behaviour and in individuals' functioning and development. Contrary to previous assumptions, it is not universal models but rather different kinds of taxonomic models that are required for each of the different kinds of phenomena, variations and structures that are commonly conceived of as "personality". Consequently, to comprehensively explore individual-specificity, researchers have to apply a portfolio of complementary methodologies and develop different kinds of taxonomies, most of which have yet to be developed. Closing, the article derives some meta-desiderata for future research on individuals' "personality".

  14. Modelling the response of stable water isotopes in Greenland precipitation to orbital configurations of the previous interglacial

    Directory of Open Access Journals (Sweden)

    Jesper Sjolte

    2014-09-01

    Full Text Available The relation between δ 18O of precipitation and temperature has been used in numerous studies to reconstruct past temperatures at ice core sites in Greenland and Antarctica. During the past two decades, it has become clear that the slope between δ 18O and temperature varies in both space and time. Here, we use a general circulation model driven by changes in orbital parameters to investigate the Greenland δ 18O–temperature relation for the previous interglacial, the Eemian. In our analysis, we focus on changes in the moisture source regions, and the results underline the importance of taking the seasonality of climate change into account. The orbitally driven experiments show that continental evaporation over North America increases during summer in the warm parts of the Eemian, while marine evaporation decreases. This likely flattens the Greenland δ 18O response to temperature during summer. Since the main climate change in the experiments occurs during summer this adds to a limited response of δ 18O, which is more strongly tied to temperature during winter than during summer. A south–west to north–east gradient in the δ 18O–temperature slope is also evident for Greenland, with low slopes in the south–west and steeper slopes in the north–east. This probably reflects the proportion of continental moisture and Arctic moisture arriving in Greenland, with more continental moisture in the south–west and less in the north–east, and vice versa for the Arctic moisture.

  15. Dynamic Model and Vibration Characteristics of Planar 3-RRR Parallel Manipulator with Flexible Intermediate Links considering Exact Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Lianchao Sheng

    2017-01-01

    Full Text Available Due to the complexity of the dynamic model of a planar 3-RRR flexible parallel manipulator (FPM, it is often difficult to achieve active vibration control algorithm based on the system dynamic model. To establish a simple and efficient dynamic model of the planar 3-RRR FPM to study its dynamic characteristics and build a controller conveniently, firstly, considering the effect of rigid-flexible coupling and the moment of inertia at the end of the flexible intermediate link, the modal function is determined with the pinned-free boundary condition. Then, considering the main vibration modes of the system, a high-efficiency coupling dynamic model is established on the basis of guaranteeing the model control accuracy. According to the model, the modal characteristics of the flexible intermediate link are analyzed and compared with the modal test results. The results show that the model can effectively reflect the main vibration modes of the planar 3-RRR FPM; in addition the model can be used to analyze the effects of inertial and coupling forces on the dynamics model and the drive torque of the drive motor. Because this model is of the less dynamic parameters, it is convenient to carry out the control program.

  16. Previous exercise training has a beneficial effect on renal and cardiovascular function in a model of diabetes.

    Directory of Open Access Journals (Sweden)

    Kleiton Augusto dos Santos Silva

    Full Text Available Exercise training (ET is an important intervention for chronic diseases such as diabetes mellitus (DM. However, it is not known whether previous exercise training intervention alters the physiological and medical complications of these diseases. We investigated the effects of previous ET on the progression of renal disease and cardiovascular autonomic control in rats with streptozotocin (STZ-induced DM. Male Wistar rats were divided into five groups. All groups were followed for 15 weeks. Trained control and trained diabetic rats underwent 10 weeks of exercise training, whereas previously trained diabetic rats underwent 14 weeks of exercise training. Renal function, proteinuria, renal sympathetic nerve activity (RSNA and the echocardiographic parameters autonomic modulation and baroreflex sensitivity (BRS were evaluated. In the previously trained group, the urinary albumin/creatinine ratio was reduced compared with the sedentary diabetic and trained diabetic groups (p<0.05. Additionally, RSNA was normalized in the trained diabetic and previously trained diabetic animals (p<0.05. The ejection fraction was increased in the previously trained diabetic animals compared with the diabetic and trained diabetic groups (p<0.05, and the myocardial performance index was improved in the previously trained diabetic group compared with the diabetic and trained diabetic groups (p<0.05. In addition, the previously trained rats had improved heart rate variability and BRS in the tachycardic response and bradycardic response in relation to the diabetic group (p<0.05. This study demonstrates that previous ET improves the functional damage that affects DM. Additionally, our findings suggest that the development of renal and cardiac dysfunction can be minimized by 4 weeks of ET before the induction of DM by STZ.

  17. Development of Grounding Resistance Analysis Model of Rod Electrode Considering the Effect of Large-Current Characteristic for Distribution Lines

    Science.gov (United States)

    Asaoka, Yoshinobu; Motoyama, Hideki; Matsubara, Hiroji; Sugimoto, Hitoshi

    Grounding resistance is one of the important parameters in the lightning-protection design of electric power systems. The grounding resistance of electrode decreases as large currents are injected to the electrode by electric discharges in soil. This characteristic is not considered in lightning protection design. Therefore, the design level is kept on the exceeding level in actual phenomena. From viewpoint of the rational lightning protection design for the electric power systems, this characteristic should be considered in practical design. In this study, experiments were conducted using rod electrodes, and the physical phenomena of the electrical discharge in soil were considered by assuming a certain electrical discharge model in soil. Based on these results, a grounding resistance large-current characteristic analysis model that could be easily used in EMTP was developed.

  18. Previous exercise training has a beneficial effect on renal and cardiovascular function in a model of diabetes.

    Science.gov (United States)

    Silva, Kleiton Augusto dos Santos; Luiz, Rafael da Silva; Rampaso, Rodolfo Rosseto; de Abreu, Nayda Parísio; Moreira, Édson Dias; Mostarda, Cristiano Teixeira; De Angelis, Kátia; de Paulo Castro Teixeira, Vicente; Irigoyen, Maria Cláudia; Schor, Nestor

    2012-01-01

    Exercise training (ET) is an important intervention for chronic diseases such as diabetes mellitus (DM). However, it is not known whether previous exercise training intervention alters the physiological and medical complications of these diseases. We investigated the effects of previous ET on the progression of renal disease and cardiovascular autonomic control in rats with streptozotocin (STZ)-induced DM. Male Wistar rats were divided into five groups. All groups were followed for 15 weeks. Trained control and trained diabetic rats underwent 10 weeks of exercise training, whereas previously trained diabetic rats underwent 14 weeks of exercise training. Renal function, proteinuria, renal sympathetic nerve activity (RSNA) and the echocardiographic parameters autonomic modulation and baroreflex sensitivity (BRS) were evaluated. In the previously trained group, the urinary albumin/creatinine ratio was reduced compared with the sedentary diabetic and trained diabetic groups (ptrained diabetic and previously trained diabetic animals (ptrained diabetic animals compared with the diabetic and trained diabetic groups (ptrained diabetic group compared with the diabetic and trained diabetic groups (ptrained rats had improved heart rate variability and BRS in the tachycardic response and bradycardic response in relation to the diabetic group (p<0.05). This study demonstrates that previous ET improves the functional damage that affects DM. Additionally, our findings suggest that the development of renal and cardiac dysfunction can be minimized by 4 weeks of ET before the induction of DM by STZ.

  19. Integrated water system simulation by considering hydrological and biogeochemical processes: model development, with parameter sensitivity and autocalibration

    Science.gov (United States)

    Zhang, Y. Y.; Shao, Q. X.; Ye, A. Z.; Xing, H. T.; Xia, J.

    2016-02-01

    Integrated water system modeling is a feasible approach to understanding severe water crises in the world and promoting the implementation of integrated river basin management. In this study, a classic hydrological model (the time variant gain model: TVGM) was extended to an integrated water system model by coupling multiple water-related processes in hydrology, biogeochemistry, water quality, and ecology, and considering the interference of human activities. A parameter analysis tool, which included sensitivity analysis, autocalibration and model performance evaluation, was developed to improve modeling efficiency. To demonstrate the model performances, the Shaying River catchment, which is the largest highly regulated and heavily polluted tributary of the Huai River basin in China, was selected as the case study area. The model performances were evaluated on the key water-related components including runoff, water quality, diffuse pollution load (or nonpoint sources) and crop yield. Results showed that our proposed model simulated most components reasonably well. The simulated daily runoff at most regulated and less-regulated stations matched well with the observations. The average correlation coefficient and Nash-Sutcliffe efficiency were 0.85 and 0.70, respectively. Both the simulated low and high flows at most stations were improved when the dam regulation was considered. The daily ammonium-nitrogen (NH4-N) concentration was also well captured with the average correlation coefficient of 0.67. Furthermore, the diffuse source load of NH4-N and the corn yield were reasonably simulated at the administrative region scale. This integrated water system model is expected to improve the simulation performances with extension to more model functionalities, and to provide a scientific basis for the implementation in integrated river basin managements.

  20. Comparison of extended mean-reversion and time series models for electricity spot price simulation considering negative prices

    International Nuclear Information System (INIS)

    Keles, Dogan; Genoese, Massimo; Möst, Dominik; Fichtner, Wolf

    2012-01-01

    This paper evaluates different financial price and time series models, such as mean reversion, autoregressive moving average (ARMA), integrated ARMA (ARIMA) and general autoregressive conditional heteroscedasticity (GARCH) process, usually applied for electricity price simulations. However, as these models are developed to describe the stochastic behaviour of electricity prices, they are extended by a separate data treatment for the deterministic components (trend, daily, weekly and annual cycles) of electricity spot prices. Furthermore price jumps are considered and implemented within a regime-switching model. Since 2008 market design allows for negative prices at the European Energy Exchange, which also occurred for several hours in the last years. Up to now, only a few financial and time series approaches exist, which are able to capture negative prices. This paper presents a new approach incorporating negative prices. The evaluation of the different approaches presented points out that the mean reversion and the ARMA models deliver the lowest mean root square error between simulated and historical electricity spot prices gained from the European Energy Exchange. These models posses also lower mean average errors than GARCH models. Hence, they are more suitable to simulate well-fitting price paths. Furthermore it is shown that the daily structure of historical price curves is better captured applying ARMA or ARIMA processes instead of mean-reversion or GARCH models. Another important outcome of the paper is that the regime-switching approach and the consideration of negative prices via the new proposed approach lead to a significant improvement of the electricity price simulation. - Highlights: ► Considering negative prices improves the results of time-series and financial models for electricity prices. ► Regime-switching approach captures the jumps and base prices quite well. ► Removing and separate modelling of deterministic annual, weekly and daily

  1. A Convex Model of Risk-Based Unit Commitment for Day-Ahead Market Clearing Considering Wind Power Uncertainty

    DEFF Research Database (Denmark)

    Zhang, Ning; Kang, Chongqing; Xia, Qing

    2015-01-01

    The integration of wind power requires the power system to be sufficiently flexible to accommodate its forecast errors. In the market clearing process, the scheduling of flexibility relies on the manner in which the wind power uncertainty is addressed in the unit commitment (UC) model. This paper...... and are considered in both the objective functions and the constraints. The RUC model is shown to be convex and is transformed into a mixed integer linear programming (MILP) problem using relaxation and piecewise linearization. The proposed RUC model is tested using a three-bus system and an IEEE RTS79 system...... that the risk modeling facilitates a strategic market clearing procedure with a reasonable computational expense....

  2. A practical kinetic model that considers endproduct inhibition in anaerobic digestion processes by including the equilibrium constant.

    Science.gov (United States)

    Hoh, C Y; Cord-Ruwisch, R

    1996-09-05

    The classical Michaelis-Menten model is widely used as the basis for modeling of a number of biological systems. As the model does not consider the inhibitory effect of endproducts that accumulate in virtually all bioprocesses, it is often modified to prevent the overestimation of reaction rates when products have accumulated. Traditional approaches of model modification use the inclusion of irreversible, competitive, and noncompetitive inhibition factors. This article demonstrates that these inhibition factors are insufficient to predict product inhibition of reactions that are close the dynamic equilibrium. All models investigated were found to violate thermodynamic laws as they predicted positive reaction rates for reactions that were endergonic due to high endproduct concentrations. For modeling of biological processes that operate close to the dynamic equilibrium (e.g., anaerobic processes), it is critical to prevent the prediction of positive reaction rates when the reaction has already reached the dynamic equilibrium. This can be achieved by using a reversible kinetic model. However, the major drawback of the reversible kinetic model is the large number of empirical parameters it requires. These parameters are difficult to determine and prone to experimental error. For this reason, the reversible model is not practical in the modeling of biological processes.This article uses the fundamentals of steady-state kinetics and thermodynamics to establish an equation for the reversible kinetic model that is of practical use in bio-process modeling. The behavior of this equilibrium-based model is compared with Michaelis-Menten-based models that use traditional inhibition factors. The equilibrium-based model did not require any empirical inhibition factor to correctly predict when reaction rates must be zero due to the free energy change being zero. For highly exergonic reactions, the equilibrium-based model did not deviate significantly from the Michaelis

  3. Laparoscopy After Previous Laparotomy

    Directory of Open Access Journals (Sweden)

    Zulfo Godinjak

    2006-11-01

    Full Text Available Following the abdominal surgery, extensive adhesions often occur and they can cause difficulties during laparoscopic operations. However, previous laparotomy is not considered to be a contraindication for laparoscopy. The aim of this study is to present that an insertion of Veres needle in the region of umbilicus is a safe method for creating a pneumoperitoneum for laparoscopic operations after previous laparotomy. In the last three years, we have performed 144 laparoscopic operations in patients that previously underwent one or two laparotomies. Pathology of digestive system, genital organs, Cesarean Section or abdominal war injuries were the most common causes of previouslaparotomy. During those operations or during entering into abdominal cavity we have not experienced any complications, while in 7 patients we performed conversion to laparotomy following the diagnostic laparoscopy. In all patients an insertion of Veres needle and trocar insertion in the umbilical region was performed, namely a technique of closed laparoscopy. Not even in one patient adhesions in the region of umbilicus were found, and no abdominal organs were injured.

  4. A multi-objective model for locating distribution centers in a supply chain network considering risk and inventory decisions

    Directory of Open Access Journals (Sweden)

    Sara Gharegozloo Hamedani

    2013-04-01

    Full Text Available This paper presents a multi-objective location problem in a three level supply chain network under uncertain environment considering inventory decisions. The proposed model of this paper considers uncertainty for different parameters including procurement, transportation costs, supply, demand and the capacity of various facilities. The proposed model presents a robust optimization model, which specifies locations of distribution centers to be opened, inventory control parameters (r, Q, and allocation of supply chain components, concurrently. The resulted mixed-integer nonlinear programming minimizes the expected total cost of such a supply chain network comprising location, procurement, transportation, holding, ordering, and shortage costs. The model also minimizes the variability of the total cost of relief chain and minimizes the financial risk or the probability of not meeting a certain budget. We use the ε-constraint method, which is a multi-objective technique with implicit trade-off information given, to solve the problem and using a couple of numerical instances, we examine the performance of the proposed approach.

  5. A Modeling Approach for Farmland Protection Zoning Considering Spatial Heterogeneity: A Case Study of E-Zhou City, China

    Directory of Open Access Journals (Sweden)

    Jianhua He

    2016-10-01

    Full Text Available Farmland protection in China is facing multiple pressures, including urbanization, population growth and ecological degradation. Primary farmland zoning was introduced as a basic state policy to ensure national food security. Previous studies about “primary farmland zoning” have always taken the factors as global linear variables, neglecting the spatial heterogeneity of the study areas. Based on the Development Priority Zoning (DPZ strategy, we present a zoning approach using Bayesian networks (BNs for considering regional differences. The networks were developed using quantitative biophysical and economic variables from multi-scale and historical change data of farmland. The simulated results substantiate that this method can ensure the agricultural quality, stability and connectivity of primary farmland. Furthermore, it can further optimize the spatial allocation of primary farmland to meet the development conditions and trends of different sub-regions, promoting the balance between the farmland protection, urban development and ecological protection of certain regions.

  6. Analytical Switching Cycle Modeling of Bidirectional High Voltage Flyback Converter for Capacitive Load Considering Core Loss Effect

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.

    2015-01-01

    With the advancement of material science, various smart materials with intrinsic capacitive property are emerging. The high voltage (HV) power electronics converters with bidirectional energy flow functionality for supplying the capacitive load are highly demanded. A switching cycle based...... analytical model of HV bidirectional converter driving capacitive load is beneficial in thoroughly understanding the operational behavior, investigating the energy efficiency and optimizing the design. In this paper, a HV bidirectional flyback converter for capacitive load is generally discussed in terms...... of configuration and working principle. Considering the parasitic elements as well as the core loss effect, the converter is modeled with analytical formulas for one switching cycle. The comparison between the model based calculation results and prototype experiments based measurement results are used to validate...

  7. Study on Time-Dependent Behavior of Granite and the Creep Model Based on Fractional Derivative Approach Considering Temperature

    Directory of Open Access Journals (Sweden)

    Zhilei He

    2016-01-01

    Full Text Available Based on mineral components and the creep experimental studies of Three Gorges granite and Beishan granite from different regions of China at various temperatures, the strength and creep property of two types of granites are compared and analyzed. Considering the damage evolution process, a new creep constitutive model is proposed to describe the creep property of granite at different temperatures based on fractional derivative. The parameters of the new creep model are determined on the basis of the experimental results of the two granites. In addition, a sensitivity study is carried out, showing effects of stress level, fractional derivative order, and the exponent m. The results indicate that the proposed creep model can describe the three creep stages of granite at different temperatures and contribute to further research on the creep property of granite.

  8. An Optimal Decision Model of Production-Inventory with MTS and ATO Hybrid Model Considering Uncertain Demand

    Directory of Open Access Journals (Sweden)

    Dezhi Zhang

    2015-01-01

    Full Text Available This paper presents an optimization decision model for a production system that comprises the hybrid make-to-stock/assemble-to-order (MTS/ATO organization mode with demand uncertainty, which can be described as a two-stage decision model. In the first decision stage (i.e., before acquiring the actual demand information of the customer, we have studied the optimal quantities of the finished products and components, while in the second stage (i.e., after acquiring the actual demand information of the customer, we have made the optimal decision on the assignment of components to satisfy the remaining demand. The optimal conditions on production and inventory decision are deduced, as well as the bounds of the total procurement quantity of the components in the ATO phase and final products generated in the MTS phase. Finally, an example is given to illustrate the above optimal model. The findings are shown as follows: the hybrid MTS and ATO production system reduces uncertain demand risk by arranging MTS phase and ATO phase reasonably and improves the expected profit of manufacturer; applying the strategy of component commonality can reduce the total inventory level, as well as the risk induced by the lower accurate demand forecasting.

  9. Modeling aeolian transport of soil-bound plutonium: considering infrequent but normal environmental disturbances is critical in estimating future dose

    International Nuclear Information System (INIS)

    Michelotti, Erika A.; Whicker, Jeffrey J.; Eisele, William F.; Breshears, David D.; Kirchner, Thomas B.

    2013-01-01

    Dose assessments typically consider environmental systems as static through time, but environmental disturbances such as drought and fire are normal, albeit infrequent, events that can impact dose-influential attributes of many environmental systems. These phenomena occur over time frames of decades or longer, and are likely to be exacerbated under projected warmer, drier climate. As with other types of dose assessment, the impacts of environmental disturbances are often overlooked when evaluating dose from aeolian transport of radionuclides and other contaminants. Especially lacking are predictions that account for potential changing vegetation cover effects on radionuclide transport over the long time frames required by regulations. A recently developed dynamic wind-transport model that included vegetation succession and environmental disturbance provides more realistic long-term predictability. This study utilized the model to estimate emission rates for aeolian transport, and compare atmospheric dispersion and deposition rates of airborne plutonium-contaminated soil into neighboring areas with and without environmental disturbances. Specifically, the objective of this study was to utilize the model results as input for a widely used dose assessment model (CAP-88). Our case study focused on low levels of residual plutonium found in soils from past operations at Los Alamos National Laboratory (LANL), in Los Alamos, NM, located in the semiarid southwestern USA. Calculations were conducted for different disturbance scenarios based on conditions associated with current climate, and a potential future drier and warmer climate. Known soil and sediment concentrations of plutonium were used to model dispersal and deposition of windblown residual plutonium, as a function of distance and direction. Environmental disturbances that affected vegetation cover included ground fire, crown fire, and drought, with reoccurrence rates for current climate based on site historical

  10. A dynamic approach for the impact of a toxic gas dispersion hazard considering human behaviour and dispersion modelling.

    Science.gov (United States)

    Lovreglio, Ruggiero; Ronchi, Enrico; Maragkos, Georgios; Beji, Tarek; Merci, Bart

    2016-11-15

    The release of toxic gases due to natural/industrial accidents or terrorist attacks in populated areas can have tragic consequences. To prevent and evaluate the effects of these disasters different approaches and modelling tools have been introduced in the literature. These instruments are valuable tools for risk managers doing risk assessment of threatened areas. Despite the significant improvements in hazard assessment in case of toxic gas dispersion, these analyses do not generally include the impact of human behaviour and people movement during emergencies. This work aims at providing an approach which considers both modelling of gas dispersion and evacuation movement in order to improve the accuracy of risk assessment for disasters involving toxic gases. The approach is applied to a hypothetical scenario including a ship releasing Nitrogen dioxide (NO2) on a crowd attending a music festival. The difference between the results obtained with existing static methods (people do not move) and a dynamic approach (people move away from the danger) which considers people movement with different degrees of sophistication (either a simple linear path or more complex behavioural modelling) is discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. A stochastic model for neutron simulation considering the spectrum and nuclear properties with continuous dependence of energy

    International Nuclear Information System (INIS)

    Camargo, Dayana Queiroz de

    2011-01-01

    This thesis has developed a stochastic model to simulate the neutrons transport in a heterogeneous environment, considering continuous neutron spectra and the nuclear properties with its continuous dependence on energy. This model was implemented using Monte Carlo method for the propagation of neutrons in different environment. Due to restrictions with respect to the number of neutrons that can be simulated in reasonable computational processing time introduced the variable control volume along the (pseudo-) periodic boundary conditions in order to overcome this problem. The choice of class physical Monte Carlo is due to the fact that it can decompose into simpler constituents the problem of solve a transport equation. The components may be treated separately, these are the propagation and interaction while respecting the laws of energy conservation and momentum, and the relationships that determine the probability of their interaction. We are aware of the fact that the problem approached in this thesis is far from being comparable to building a nuclear reactor, but this discussion the main target was to develop the Monte Carlo model, implement the code in a computer language that allows extensions of modular way. This study allowed a detailed analysis of the influence of energy on the neutron population and its impact on the life cycle of neutrons. From the results, even for a simple geometrical arrangement, we can conclude the need to consider the energy dependence, i.e. an spectral effective multiplication factor should be introduced each energy group separately. (author)

  12. A novel model for through-silicon via (TSV) filling process simulation considering three additives and current density effect

    Science.gov (United States)

    Wang, Fuliang; Zhao, Zhipeng; Wang, Feng; Wang, Yan; Nie, Nantian

    2017-12-01

    Through-silicon via (TSV) filling by electrochemical deposition is still a challenge for 3D IC packaging, and three-component additive systems (accelerator, suppressor, and leveler) were commonly used in the industry to achieve void-free filling. However, models considering three additive systems and the current density effect have not been fully studied. In this paper, a novel three-component model was developed to study the TSV filling mechanism and process, where the interaction behavior of the three additives (accelerator, suppressor, and leveler) were considered, and the adsorption, desorption, and consumption coefficient of the three additives were changed with the current density. Based on this new model, the three filling types (seam void, ‘V’ shape, and key hole) were simulated under different current density conditions, and the filling results were verified by experiments. The effect of the current density on the copper ion concentration, additives surface coverage, and local current density distribution during the TSV filling process were obtained. Based on the simulation and experimental results, the diffusion–adsorption–desorption–consumption competition behavior between the suppressor, the accelerator, and the leveler were discussed. The filling mechanisms under different current densities were also analyzed.

  13. Performance prediction of PM 2.5 removal of real fibrous filters with a novel model considering rebound effect

    OpenAIRE

    Cai, Rong-Rong; Zhang, Li-Zhi; Yan, Yuying

    2017-01-01

    Fibrous filters have been proved to be one of the most cost-effective way of particulate matters (specifically PM 2.5) purification. However, due to the complex structure of real fibrous filters, it is difficult to accurately predict the performance of PM2.5 removal. In this study, a new 3D filtration modeling approach is proposed to predict the removal efficiencies of particles by real fibrous filters, by taking the particle rebound effect into consideration. A real filter is considered and ...

  14. Per-Oral Endoscopic Myotomy (POEM) After Previous Laparoscopic Heller Myotomy Is Feasible and Safe in a Porcine Model.

    Science.gov (United States)

    Miles, Luke F; Frelich, Matthew J; Gould, Jon C; Dua, Kulwinder S; Jensen, Eric S; Kastenmeier, Andrew S

    2015-10-01

    We sought to evaluate the feasibility, safety, and difficulty of performing the per-oral endoscopic myotomy (POEM) procedure in the setting of a prior Heller myotomy using a survival porcine model. Four pigs underwent laparoscopic Heller myotomy with Dor partial anterior fundoplication followed by the POEM performed 4 weeks later. Two additional pigs served as controls, undergoing only the POEM. All procedures were completed without complications. The revisional POEM was not significantly more difficult than POEM controls based on procedure time, POEM procedure components, or procedure difficulty scores. Revisional POEM had a longer mean operative time when compared with Heller myotomy (126.0 vs. 83.8 min; Pmyotomy is safe and feasible in the porcine model and has potential as an option for patients suffering from recurrent or persistent symptoms after failed surgical myotomy.

  15. Use of a PBPK model with dose-dependent elimination rates predicts higher peak dioxin exposures than previously estimated

    Energy Technology Data Exchange (ETDEWEB)

    Emond, C. [NRC, NAS, WA, DC (United States); Michalek, J.E. [Air Force Research Lab., Brooks City-Base, TX (United States); Birnbaum, L.S.; DeVito, M.J. [PKB, ETD, ORD, NHEERL U.S. EPA, RTP, NC (United States)

    2004-09-15

    Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is associated with increased risk for cancer, diabetes and reproductive toxicities in numerous epidemiological studies. Several of these studies base exposure estimates on measurements of blood levels years after the accidental or occupational exposures. Peak exposures have been estimated in these studies assuming a mono or biphasic elimination rate for TCDD, with estimates of half-life ranging from 5 to 12 years. Recent clinical studies suggest that the elimination rate of TCDD is dose dependent. To address this question a physiologically based pharmacokinetic (PBPK) model can be used to predict the concentration of TCDD with a dose-dependent elimination rate. The aims of this study were to validate a dose-dependent elimination rate by using a PBPK model and to adequately predict the concentration of TCDD shortly after the exposure.

  16. Development of Swimming Human Simulation Model Considering Rigid Body Dynamics and Unsteady Fluid Force for Whole Body

    Science.gov (United States)

    Nakashima, Motomu; Satou, Ken; Miura, Yasufumi

    The purpose of this study is to develop a swimming human simulation model considering rigid body dynamics and unsteady fluid force for the whole body, which will be utilized to analyze various dynamical problems in human swimming. First, the modeling methods and their formulations for the human body and the fluid force are respectively described. Second, experiments to identify the coefficients of the normal drag and the added mass are conducted by use of an experimental setup, in which a limb model rotates in the water, and its rotating angle and the bending moment at the root are measured. As the result of the identification, the present model for the fluid force was found to have satisfactory performance in order to represent the unsteady fluctuations of the experimental data, although it has 10% error. Third, a simulation for the gliding position is conducted in order to identify the tangential drag coefficient. Finally, a simulation example of standard six beat front crawl swimming is shown. The swimming speed of the simulation became a reasonable value, indicating the validity of the present simulation model, although it is 7.5% lower than the actual swimming.

  17. Numerical solution of a logistic growth model for a population with Allee effect considering fuzzy initial values and fuzzy parameters

    Science.gov (United States)

    Amarti, Z.; Nurkholipah, N. S.; Anggriani, N.; Supriatna, A. K.

    2018-03-01

    Predicting the future of population number is among the important factors that affect the consideration in preparing a good management for the population. This has been done by various known method, one among them is by developing a mathematical model describing the growth of the population. The model usually takes form in a differential equation or a system of differential equations, depending on the complexity of the underlying properties of the population. The most widely used growth models currently are those having a sigmoid solution of time series, including the Verhulst logistic equation and the Gompertz equation. In this paper we consider the Allee effect of the Verhulst’s logistic population model. The Allee effect is a phenomenon in biology showing a high correlation between population size or density and the mean individual fitness of the population. The method used to derive the solution is the Runge-Kutta numerical scheme, since it is in general regarded as one among the good numerical scheme which is relatively easy to implement. Further exploration is done via the fuzzy theoretical approach to accommodate the impreciseness of the initial values and parameters in the model.

  18. Modeling aeolian transport of soil-bound plutonium: considering infrequent but normal environmental disturbances is critical in estimating future dose.

    Science.gov (United States)

    Michelotti, Erika A; Whicker, Jeffrey J; Eisele, William F; Breshears, David D; Kirchner, Thomas B

    2013-06-01

    Dose assessments typically consider environmental systems as static through time, but environmental disturbances such as drought and fire are normal, albeit infrequent, events that can impact dose-influential attributes of many environmental systems. These phenomena occur over time frames of decades or longer, and are likely to be exacerbated under projected warmer, drier climate. As with other types of dose assessment, the impacts of environmental disturbances are often overlooked when evaluating dose from aeolian transport of radionuclides and other contaminants. Especially lacking are predictions that account for potential changing vegetation cover effects on radionuclide transport over the long time frames required by regulations. A recently developed dynamic wind-transport model that included vegetation succession and environmental disturbance provides more realistic long-term predictability. This study utilized the model to estimate emission rates for aeolian transport, and compare atmospheric dispersion and deposition rates of airborne plutonium-contaminated soil into neighboring areas with and without environmental disturbances. Specifically, the objective of this study was to utilize the model results as input for a widely used dose assessment model (CAP-88). Our case study focused on low levels of residual plutonium found in soils from past operations at Los Alamos National Laboratory (LANL), in Los Alamos, NM, located in the semiarid southwestern USA. Calculations were conducted for different disturbance scenarios based on conditions associated with current climate, and a potential future drier and warmer climate. Known soil and sediment concentrations of plutonium were used to model dispersal and deposition of windblown residual plutonium, as a function of distance and direction. Environmental disturbances that affected vegetation cover included ground fire, crown fire, and drought, with reoccurrence rates for current climate based on site historical

  19. A strategic decision-making model considering the social costs of carbon dioxide emissions for sustainable supply chain management.

    Science.gov (United States)

    Tseng, Shih-Chang; Hung, Shiu-Wan

    2014-01-15

    Incorporating sustainability into supply chain management has become a critical issue driven by pressures from governments, customers, and various stakeholder groups over the past decade. This study proposes a strategic decision-making model considering both the operational costs and social costs caused by the carbon dioxide emissions from operating such a supply chain network for sustainable supply chain management. This model was used to evaluate carbon dioxide emissions and operational costs under different scenarios in an apparel manufacturing supply chain network. The results showed that the higher the social cost rate of carbon dioxide emissions, the lower the amount of the emission of carbon dioxide. The results also suggested that a legislation that forces the enterprises to bear the social costs of carbon dioxide emissions resulting from their economic activities is an effective approach to reducing carbon dioxide emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. A drain current model for amorphous InGaZnO thin film transistors considering temperature effects

    Science.gov (United States)

    Cai, M. X.; Yao, R. H.

    2018-03-01

    Temperature dependent electrical characteristics of amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) are investigated considering the percolation and multiple trapping and release (MTR) conduction mechanisms. Carrier-density and temperature dependent carrier mobility in a-IGZO is derived with the Boltzmann transport equation, which is affected by potential barriers above the conduction band edge with Gaussian-like distributions. The free and trapped charge densities in the channel are calculated with Fermi-Dirac statistics, and the field effective mobility of a-IGZO TFTs is then deduced based on the MTR theory. Temperature dependent drain current model for a-IGZO TFTs is finally derived with the obtained low field mobility and free charge density, which is applicable to both non-degenerate and degenerate conductions. This physical-based model is verified by available experiment results at various temperatures.

  1. AN INVENTORY MODEL WITH REWORKING AND SETUP TIME TO CONSIDER EFFECT OF INFLATION AND TIME VALUE OF MONEY

    Directory of Open Access Journals (Sweden)

    IMAN SEYEDI

    2016-03-01

    Full Text Available This paper investigates the effect of inflation and time value of money on an economic production quantity (EPQ model in the single product system while the shortage of inventory is not allowed and production of defective parts during the production process and also setup time for reworking have been considered that can be non-zero. Studies show that considering the production of defective parts and reworking, the effect of inflation rate and the time value of money in EPQ model leads to change the optimal Production batch size. Since cost function is complex and finding the optimal solution is not simple, so in this study the approximate values of close to the optimal which obtained by Inventory-Total Cost chart, has been used of investigation of the effect of inflation and the time value of money on an economic quantity of production. Numerical calculations show that lack of attention to inflation and time value of money causes relatively high and unavoidably error in the cost.

  2. Investigation the impact of outsourcing on competitive advantages' creation by considering Porter's model; Case study: Zamyad Company

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Kasrai

    2012-08-01

    Full Text Available Competitive advantage is an important factor in boosting companies' success and is considered more emphatically in management and strategic marketing literature in recent years. There are many different ideas about effective factors in creation of competitive advantages. Also fast rate of change in business, is forcing CEOs to utilize some strategies, which have the best impact on current organizational circumstances and the future trend of investigation in organizational trades. Outsourcing is one of the best strategies, which are widely utilized by CEOs in different organizations. Many managers believe that outsourcing is the solitary way for preserving the balance of organization in 21 century. Based on Porter competitive advantage model, there are three strategies, which lead a company to reach competitive advantage. These strategies are cost leadership, differentiation strategy and segmentation strategy. In this article, we are investigating outsourcing effects on creation of competitive advantages through Porter model in an automotive factory in Iran. We design a questionnaire for gathering necessary information about the role of outsourcing in creation of different strategies as competitive advantages in managers' point of view. We analyze the questionnaires and implement a goodness of fit test to recognize the distribution of data and the statistical method. Preliminary results show that nonparametric statistic methods can be utilized for testing our hypothesis. We use a Wilcoxon test to consider the null hypothesis and a Friedman test to estimate the rank of means. Our findings verify an undeniable effect of outsourcing on creation of competitive advantage and the ranking list is presented.

  3. Considering a Threshold Energy in Reactive Transport Modeling of Microbially Mediated Redox Reactions in an Arsenic-Affected Aquifer

    Directory of Open Access Journals (Sweden)

    Marco Rotiroti

    2018-01-01

    Full Text Available The reductive dissolution of Fe-oxide driven by organic matter oxidation is the primary mechanism accepted for As mobilization in several alluvial aquifers. These processes are often mediated by microorganisms that require a minimum Gibbs energy available to conduct the reaction in order to sustain their life functions. Implementing this threshold energy in reactive transport modeling is rarely used in the existing literature. This work presents a 1D reactive transport modeling of As mobilization by the reductive dissolution of Fe-oxide and subsequent immobilization by co-precipitation in iron sulfides considering a threshold energy for the following terminal electron accepting processes: (a Fe-oxide reduction, (b sulfate reduction, and (c methanogenesis. The model is then extended by implementing a threshold energy on both reaction directions for the redox reaction pairs Fe(III reduction/Fe(II oxidation and methanogenesis/methane oxidation. The optimal threshold energy fitted in 4.50, 3.76, and 1.60 kJ/mol e− for sulfate reduction, Fe(III reduction/Fe(II oxidation, and methanogenesis/methane oxidation, respectively. The use of models implementing bidirectional threshold energy is needed when a redox reaction pair can be transported between domains with different redox potentials. This may often occur in 2D or 3D simulations.

  4. Modelling and simulation of a direct ethanol fuel cell considering multistep electrochemical reactions, transport processes and mixed potentials

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Marco [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Melke, Julia, E-mail: julia.melke@gmail.co [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Gerteisen, Dietmar [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany)

    2011-04-15

    Highlights: A DEFC model considering the mixed potential formation at cathode and anode. The low cell voltage at open circuit is due to the parasitic reaction of ethanol and oxygen. Under load, only the parasitic oxidation of ethanol is significant. Inhibiting the parasitic reactions can approximately double the current density. - Abstract: In this work a one-dimensional mathematical model of a direct ethanol fuel cell (DEFC) is presented. The electrochemical oxidation of ethanol in the catalyst layers is described by several reaction steps leading to surface coverage with adsorbed intermediates (CH{sub 3}CO, CO, CH{sub 3} and OH) and to the final products acetaldehyde, acetic acid and CO{sub 2}. A bifunctional reaction mechanism is assumed for the activation of water on a binary catalyst favouring the further oxidation of adsorbates blocking active catalyst sites. The chemical reactions are highly coupled with the charge and reactant transport. The model accounts for crossover of the reactants through the membrane leading to the phenomenon of cathode and anode mixed potentials due to the parasitic oxidation and reduction of ethanol and oxygen, respectively. Polarisation curves of a DEFC were recorded for various ethanol feed concentrations and were used as reference data for the simulation. Based on one set of model parameters the characteristic of electronic and protonic potential, the relative surface coverage and the parasitic current densities in the catalyst layers were studied.

  5. Development of discrete choice model considering internal reference points and their effects in travel mode choice context

    Science.gov (United States)

    Sarif; Kurauchi, Shinya; Yoshii, Toshio

    2017-06-01

    In the conventional travel behavior models such as logit and probit, decision makers are assumed to conduct the absolute evaluations on the attributes of the choice alternatives. On the other hand, many researchers in cognitive psychology and marketing science have been suggesting that the perceptions of attributes are characterized by the benchmark called “reference points” and the relative evaluations based on them are often employed in various choice situations. Therefore, this study developed a travel behavior model based on the mental accounting theory in which the internal reference points are explicitly considered. A questionnaire survey about the shopping trip to the CBD in Matsuyama city was conducted, and then the roles of reference points in travel mode choice contexts were investigated. The result showed that the goodness-of-fit of the developed model was higher than that of the conventional model, indicating that the internal reference points might play the major roles in the choice of travel mode. Also shown was that the respondents seem to utilize various reference points: some tend to adopt the lowest fuel price they have experienced, others employ fare price they feel in perceptions of the travel cost.

  6. Model-based derivation, analysis and control of unstable microaerobic steady-states--considering Rhodospirillum rubrum as an example.

    Science.gov (United States)

    Carius, Lisa; Rumschinski, Philipp; Faulwasser, Timm; Flockerzi, Dietrich; Grammel, Hartmut; Findeisen, Rolf

    2014-04-01

    Microaerobic (oxygen-limited) conditions are critical for inducing many important microbial processes in industrial or environmental applications. At very low oxygen concentrations, however, the process performance often suffers from technical limitations. Available dissolved oxygen measurement techniques are not sensitive enough and thus control techniques, that can reliable handle these conditions, are lacking. Recently, we proposed a microaerobic process control strategy, which overcomes these restrictions and allows to assess different degrees of oxygen limitation in bioreactor batch cultivations. Here, we focus on the design of a control strategy for the automation of oxygen-limited continuous cultures using the microaerobic formation of photosynthetic membranes (PM) in Rhodospirillum rubrum as model phenomenon. We draw upon R. rubrum since the considered phenomenon depends on the optimal availability of mixed-carbon sources, hence on boundary conditions which make the process performance challenging. Empirically assessing these specific microaerobic conditions is scarcely practicable as such a process reacts highly sensitive to changes in the substrate composition and the oxygen availability in the culture broth. Therefore, we propose a model-based process control strategy which allows to stabilize steady-states of cultures grown under these conditions. As designing the appropriate strategy requires a detailed knowledge of the system behavior, we begin by deriving and validating an unstructured process model. This model is used to optimize the experimental conditions, and identify properties of the system which are critical for process performance. The derived model facilitates the good process performance via the proposed optimal control strategy. In summary the presented model-based control strategy allows to access and maintain microaerobic steady-states of interest and to precisely and efficiently transfer the culture from one stable microaerobic steady

  7. THREE-PHASE TRANSFORMER PARAMETERS CALCULATION CONSIDERING THE CORE SATURATION FOR THE MATLAB-SIMULINK TRANSFORMER MODEL

    Directory of Open Access Journals (Sweden)

    I. V. Novash

    2015-01-01

    Full Text Available This article describes the parameters calculation for the three-phase two-winding power transformer model taken from the SimPowerSystems library, which is the part of the MatLab- Simulink environment. Presented methodology is based on the power transformer nameplate data usage. Particular attention is paid to the power transformer magnetization curve para- meters  calculation.  The  methodology  of  the  three-phase  two-winding  power  transformer model parameters calculation considering the magnetization curve nonlinearity isn’t presented in Russian-and English-language sources. Power transformers demo models described in the SimPowerSystems user’s guide have already calculated parameters, but without reference to the sources of their determination. A power transformer is a nonlinear element of the power system, that’s why for its performance analysis in different modes of operation is necessary to have the magnetization curve parameters.The process analysis during no-load energizing of the power transformer is of special interest. This regime is accompanied by the inrush current on the supply side of the power transformer, which is several times larger than the transformer rated current. Sharp rising of the magnetizing current is explained by the magnetic core saturation. Therefore, magnetiza- tion characteristic accounting during transformer no-load energizing modeling is a mandatory requirement. Article authors attempt to put all calculating formulas in a more convenient form and validate the power transformer nonlinear magnetization characteristics parameters calcu- lation. Inrush current oscillograms obtained during the simulation experiment confirmed the adequacy of the calculated model parameters.

  8. Assessment of natural frequency of installed offshore wind turbines using nonlinear finite element model considering soil-monopile interaction

    Directory of Open Access Journals (Sweden)

    Djillali Amar Bouzid

    2018-04-01

    Full Text Available A nonlinear finite element model is developed to examine the lateral behaviors of monopiles, which support offshore wind turbines (OWTs chosen from five different offshore wind farms in Europe. The simulation is using this model to accurately estimate the natural frequency of these slender structures, as a function of the interaction of the foundations with the subsoil. After a brief introduction to the wind power energy as a reliable alternative in comparison to fossil fuel, the paper focuses on concept of natural frequency as a primary indicator in designing the foundations of OWTs. Then the range of natural frequencies is provided for a safe design purpose. Next, an analytical expression of an OWT natural frequency is presented as a function of soil-monopile interaction through monopile head springs characterized by lateral stiffness KL, rotational stiffness KR and cross-coupling stiffness KLR, of which the differences are discussed. The nonlinear pseudo three-dimensional finite element vertical slices model has been used to analyze the lateral behaviors of monopiles supporting the OWTs of different wind farm sites considered. Through the monopiles head movements (displacements and rotations, the values of KL, KR and KLR were obtained and substituted in the analytical expression of natural frequency for comparison. The comparison results between computed and measured natural frequencies showed an excellent agreement for most cases. This confirms the convenience of the finite element model used for the accurate estimation of the monopile head stiffness. Keywords: Nonlinear finite element analysis, Vertical slices model, Monopiles under horizontal loading, Natural frequency, Monopile head stiffness, Offshore wind turbines (OWTs

  9. A two-step ionospheric modeling algorithm considering the impact of GLONASS pseudo-range inter-channel biases

    Science.gov (United States)

    Zhang, Rui; Yao, Yi-bin; Hu, Yue-ming; Song, Wei-wei

    2017-12-01

    The Global Navigation Satellite System presents a plausible and cost-effective way of computing the total electron content (TEC). But TEC estimated value could be seriously affected by the differential code biases (DCB) of frequency-dependent satellites and receivers. Unlike GPS and other satellite systems, GLONASS adopts a frequency-division multiplexing access mode to distinguish different satellites. This strategy leads to different wavelengths and inter-frequency biases (IFBs) for both pseudo-range and carrier phase observations, whose impacts are rarely considered in ionospheric modeling. We obtained observations from four groups of co-stations to analyze the characteristics of the GLONASS receiver P1P2 pseudo-range IFB with a double-difference method. The results showed that the GLONASS P1P2 pseudo-range IFB remained stable for a period of time and could catch up to several meters, which cannot be absorbed by the receiver DCB during ionospheric modeling. Given the characteristics of the GLONASS P1P2 pseudo-range IFB, we proposed a two-step ionosphere modeling method with the priori IFB information. The experimental analysis showed that the new algorithm can effectively eliminate the adverse effects on ionospheric model and hardware delay parameters estimation in different space environments. During high solar activity period, compared to the traditional GPS + GLONASS modeling algorithm, the absolute average deviation of TEC decreased from 2.17 to 2.07 TECu (TEC unit); simultaneously, the average RMS of GPS satellite DCB decreased from 0.225 to 0.219 ns, and the average deviation of GLONASS satellite DCB decreased from 0.253 to 0.113 ns with a great improvement in over 55%.

  10. A one-dimensional semi-empirical model considering transition boiling effect for dispersed flow film boiling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu-Jou [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Pan, Chin, E-mail: cpan@ess.nthu.edu.tw [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Low Carbon Energy Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China)

    2017-05-15

    Highlights: • Seven heat transfer mechanisms are studied numerically by the model. • A semi-empirical method is proposed to account for the transition boiling effect. • The parametric effects on the heat transfer mechanisms are investigated. • The thermal non-equilibrium phenomenon between vapor and droplets is investigated. - Abstract: The objective of this paper is to develop a one-dimensional semi-empirical model for the dispersed flow film boiling considering transition boiling effects. The proposed model consists of conservation equations, i.e., vapor mass, vapor energy, droplet mass and droplet momentum conservation, and a set of closure relations to address the interactions among wall, vapor and droplets. The results show that the transition boiling effect is of vital importance in the dispersed flow film boiling regime, since the flowing situation in the downstream would be influenced by the conditions in the upstream. In addition, the present paper, through evaluating the vapor temperature and the amount of heat transferred to droplets, investigates the thermal non-equilibrium phenomenon under different flowing conditions. Comparison of the wall temperature predictions with the 1394 experimental data in the literature, the present model ranging from system pressure of 30–140 bar, heat flux of 204–1837 kW/m{sup 2} and mass flux of 380–5180 kg/m{sup 2} s, shows very good agreement with RMS of 8.80% and standard deviation of 8.81%. Moreover, the model well depicts the thermal non-equilibrium phenomenon for the dispersed flow film boiling.

  11. Optimal stochastic management of renewable MG (micro-grids) considering electro-thermal model of PV (photovoltaic)

    International Nuclear Information System (INIS)

    Najibi, Fatemeh; Niknam, Taher; Kavousi-Fard, Abdollah

    2016-01-01

    This paper aims to report the results of the research conducted to one thermal and electrical model for photovoltaic. Moreover, one probabilistic framework is introduced for considering all uncertainties in the optimal energy management of Micro-Grid problem. It should be noted that one typical Micro-Grid is being studied as a case, including different renewable energy sources, such as Photovoltaic, Micro Turbine, Wind Turbine, and one battery as a storage device for storing energy. The uncertainties of market price variation, photovoltaic and wind turbine output power change and load demand error are covered by the suggested probabilistic framework. The Micro-Grid problem is of nonlinear nature because of the stochastic behavior of the renewable energy sources such as Photovoltaic and Wind Turbine units, and hence there is need for a powerful tool to solve the problem. Therefore, in addition to the simulated thermal model and suggested probabilistic framework, a new algorithm is also introduced. The Backtracking Search Optimization Algorithm is described as a useful method to optimize the MG (micro-grids) problem. This algorithm has the benefit of escaping from the local optima while converging fast, too. The proposed algorithm is also tested on the typical Micro-Grid. - Highlights: • Proposing an electro-thermal model for PV. • Proposing a new stochastic formulation for optimal operation of renewable MGs. • Introduction of a new optimization method based on BSO to explore the problem search space.

  12. Studies on an Electromagnetic Transient Model of Offshore Wind Turbines and Lightning Transient Overvoltage Considering Lightning Channel Wave Impedance

    Directory of Open Access Journals (Sweden)

    Li Zhang

    2017-12-01

    Full Text Available In recent years, with the rapid development of offshore wind turbines (WTs, the problem of lightning strikes has become more and more prominent. In order to reduce the failure rate caused by the transient overvoltage of lightning struck offshore WTs, the influencing factors and the response rules of transient overvoltage are analyzed. In this paper, a new integrated electromagnetic transient model of offshore WTs is established by using the numerical calculation method of the electromagnetic field first. Then, based on the lightning model and considering the impedance of the lightning channel, the transient overvoltage of lightning is analyzed. Last, the electromagnetic transient model of offshore WTs is simulated and analyzed by using the alternative transients program electro-magnetic transient program (ATP-EMTP software. The influence factors of lightning transient overvoltage are studied. The main influencing factors include the sea depth, the blade length, the tower height, the lightning flow parameters, the lightning strike point, and the blade rotation position. The simulation results show that the influencing factors mentioned above have different effects on the lightning transient overvoltage. The results of the study have some guiding significance for the design of the lightning protection of the engine room.

  13. Mathematical Modeling and a Hybrid NSGA-II Algorithm for Process Planning Problem Considering Machining Cost and Carbon Emission

    Directory of Open Access Journals (Sweden)

    Jin Huang

    2017-09-01

    Full Text Available Process planning is an important function in a manufacturing system; it specifies the manufacturing requirements and details for the shop floor to convert a part from raw material to the finished form. However, considering only economical criterion with technological constraints is not enough in sustainable manufacturing practice; formerly, criteria about low carbon emission awareness have seldom been taken into account in process planning optimization. In this paper, a mathematical model that considers both machining costs reduction as well as carbon emission reduction is established for the process planning problem. However, due to various flexibilities together with complex precedence constraints between operations, the process planning problem is a non-deterministic polynomial-time (NP hard problem. Aiming at the distinctive feature of the multi-objectives process planning optimization, we then developed a hybrid non-dominated sorting genetic algorithm (NSGA-II to tackle this problem. A local search method that considers both the total cost criterion and the carbon emission criterion are introduced into the proposed algorithm to avoid being trapped into local optima. Moreover, the technique for order preference by similarity to an ideal solution (TOPSIS method is also adopted to determine the best solution from the Pareto front. Experiments have been conducted using Kim’s benchmark. Computational results show that process plan schemes with low carbon emission can be captured, and, more importantly, the proposed hybrid NSGA-II algorithm can obtain more promising optimal Pareto front than the plain NSGA-II algorithm. Meanwhile, according to the computational results of Kim’s benchmark, we find that both of the total machining cost and carbon emission are roughly proportional to the number of operations, and a process plan with less operation may be more satisfactory. This study will draw references for the further research on green

  14. Mathematical Model and Analysis of the Water-Lubricated Hydrostatic Journal Bearings considering the Translational and Tilting Motions

    Directory of Open Access Journals (Sweden)

    Hui-Hui Feng

    2014-01-01

    Full Text Available The water-lubricated bearings have been paid attention for their advantages to reduce the power loss and temperature rise and increase load capacity at high speed. To fully study the complete dynamic coefficients of two water-lubricated, hydrostatic journal bearings used to support a rigid rotor, a four-degree-of-freedom model considering the translational and tilting motion is presented. The effects of tilting ratio, rotary speed, and eccentricity ratio on the static and dynamic performances of the bearings are investigated. The bulk turbulent Reynolds equation is adopted. The finite difference method and a linear perturbation method are used to calculate the zeroth- and first-order pressure fields to obtain the static and dynamic coefficients. The results suggest that when the tilting ratio is smaller than 0.4 or the eccentricity ratio is smaller than 0.1, the static and dynamic characteristics are relatively insensitive to the tilting and eccentricity ratios; however, for larger tilting or eccentricity ratios, the tilting and eccentric effects should be fully considered. Meanwhile, the rotary speed significantly affects the performance of the hydrostatic, water-lubricated bearings.

  15. Development of a Model for a Cordon Pricing Scheme Considering Environmental Equity: A Case Study of Tehran

    Directory of Open Access Journals (Sweden)

    Shahriar Afandizadeh

    2016-02-01

    Full Text Available Congestion pricing strategy has been recognized as an effective countermeasure in the practical field of urban traffic congestion mitigation. Despite the positive effects of congestion pricing, its implementation has faced problems. This paper investigates the issue of environmental equity in cordon pricing and a park-and-ride scheme. Although pollution decreases inside the cordon by implementation of cordon pricing, air pollutants emission may increase in some links and in the whole network. Therefore, an increase in air emissions in the network means more emission outside the cordon. In fact, due to the implementation of this policy, air pollutants emission may transfer from inside to outside the cordon, creating a type of environmental inequity. To reduce this inequity, a bi-level optimization model with an equity constraint is developed. The proposed solution algorithm based on the second version of the strength Pareto evolutionary algorithm (SPEA2 is applied to the city network in Tehran. The results revealed that it seems reasonable to consider environmental equity as an objective function in cordon pricing. In addition, we can create a sustainable situation for the transportation system by improving environmental inequity with a relatively low reduction in social welfare. Moreover, there are environmental inequity impacts in real networks, which should be considered in the cordon pricing scheme.

  16. Multi-Period Optimization Model for Electricity Generation Planning Considering Plug-in Hybrid Electric Vehicle Penetration

    Directory of Open Access Journals (Sweden)

    Lena Ahmadi

    2015-05-01

    Full Text Available One of the main challenges for widespread penetration of plug-in hybrid electric vehicles (PHEVs is their impact on the electricity grid. The energy sector must anticipate and prepare for this extra demand and implement long-term planning for electricity production. In this paper, the additional electricity demand on the Ontario electricity grid from charging PHEVs is incorporated into an electricity production planning model. A case study pertaining to Ontario energy planning is considered to optimize the value of the cost of the electricity over sixteen years (2014–2030. The objective function consists of the fuel costs, fixed and variable operating and maintenance costs, capital costs for new power plants, and the retrofit costs of existing power plants. Five different case studies are performed with different PHEVs penetration rates, types of new power plants, and CO2 emission constraints. Among all the cases studied, the one requiring the most new capacity, (~8748 MW, is assuming the base case with 6% reduction in CO2 in year 2018 and high PHEV penetration. The next highest one is the base case, plus considering doubled NG prices, PHEV medium penetration rate and no CO2 emissions reduction target with an increase of 34.78% in the total installed capacity in 2030. Furthermore, optimization results indicate that by not utilizing coal power stations the CO2 emissions are the lowest: ~500 tonnes compared to ~900 tonnes when coal is permitted.

  17. Modeling and Vulnerability Analysis of Cyber-Physical Power Systems Considering Network Topology and Power Flow Properties

    Directory of Open Access Journals (Sweden)

    Jia Guo

    2017-01-01

    Full Text Available Conventional power systems are developing into cyber-physical power systems (CPPS with wide applications of communication, computer and control technologies. However, multiple practical cases show that the failure of cyber layers is a major factor leading to blackouts. Therefore, it is necessary to discuss the cascading failure process considering cyber layer failures and analyze the vulnerability of CPPS. In this paper, a CPPS model, which consists of cyber layer, physical layer and cyber-physical interface, is presented using complex network theory. Considering power flow properties, the impacts of cyber node failures on the cascading failure propagation process are studied. Moreover, two vulnerability indices are established from the perspective of both network structure and power flow properties. A vulnerability analysis method is proposed, and the CPPS performance before and after cascading failures is analyzed by the proposed method to calculate vulnerability indices. In the case study, three typical scenarios are analyzed to illustrate the method, and vulnerabilities under different interface strategies and attack strategies are compared. Two thresholds are proposed to value the CPPS vulnerability roughly. The results show that CPPS is more vulnerable under malicious attacks and cyber nodes with high indices are vulnerable points which should be reinforced.

  18. Changes in the structure and function of northern Alaskan ecosystems when considering variable leaf-out times across groupings of species in a dynamic vegetation model

    Science.gov (United States)

    Euskirchen, E.S.; Carman, T.B.; McGuire, Anthony David

    2013-01-01

    The phenology of arctic ecosystems is driven primarily by abiotic forces, with temperature acting as the main determinant of growing season onset and leaf budburst in the spring. However, while the plant species in arctic ecosystems require differing amounts of accumulated heat for leaf-out, dynamic vegetation models simulated over regional to global scales typically assume some average leaf-out for all of the species within an ecosystem. Here, we make use of air temperature records and observations of spring leaf phenology collected across dominant groupings of species (dwarf birch shrubs, willow shrubs, other deciduous shrubs, grasses, sedges, and forbs) in arctic and boreal ecosystems in Alaska. We then parameterize a dynamic vegetation model based on these data for four types of tundra ecosystems (heath tundra, shrub tundra, wet sedge tundra, and tussock tundra), as well as ecotonal boreal white spruce forest, and perform model simulations for the years 1970 -2100. Over the course of the model simulations, we found changes in ecosystem composition under this new phenology algorithm compared to simulations with the previous phenology algorithm. These changes were the result of the differential timing of leaf-out, as well as the ability for the groupings of species to compete for nitrogen and light availability. Regionally, there were differences in the trends of the carbon pools and fluxes between the new phenology algorithm and the previous phenology algorithm, although these differences depended on the future climate scenario. These findings indicate the importance of leaf phenology data collection by species and across the various ecosystem types within the highly heterogeneous Arctic landscape, and that dynamic vegetation models should consider variation in leaf-out by groupings of species within these ecosystems to make more accurate projections of future plant distributions and carbon cycling in Arctic regions.

  19. Experimental and analytical studies of a deeply embedded reactor building model considering soil-building interaction. Pt. 3

    International Nuclear Information System (INIS)

    Tanaka, H.

    1983-01-01

    The paper describes the dynamic charachteristics of a deeply embedded reactor building model obtained from the forced vibration tests, earthquake observations and simulation analysis. The earthquake records of the structure and the surrounding soil were examined by using soil-building interaction model as used in the analyses of the forced vibration tests. It is considered that the response of the structure will be influenced by the seismic behaviour of the soil layer as the seismic wave is input to the bedrock of the soil-structure interaction model in the earthquake response analysis. Therefore, dynamic properties of the soil layer during earthquakes were investigated in detail, and applied to the seismic simulation analysis using soil-structure interaction model. Many earthquake records have been obtained since June, 1976 when the earthquake observation system was first established. From these, eight of them which had comparatively large acceleration values were used to investigate the transfer properties of soil layer. Besides, transfer functions computed using in-situ measurement shearing wave velocity showed good agreement with those of the earthquake records. The records of the Miyagiken-oki earthquake of February 20, 1978 (magnitude 6.7) was selected as an example for performing simulation analysis. The simulation analysis are as follows: (1) In the seismic simulation analysis using soil-structure interaction modal, computed results will be in good agreement with the observed ones, when the transfer function of soil layer is properly estimated. (2) Judging from the transfer function of soil layer with the characteristics that the modal damping value decreases gradually at a higher modal frequency, it is found that ddamping of soil-layer can be simulated more adequately by introducing external damping system together with structural damping. (orig./HP)

  20. Cluster emission at pre-equilibrium stage in Heavy Nuclear Reactions. A Model considering the Thermodynamics of Small Systems

    International Nuclear Information System (INIS)

    Bermudez Martinez, A.; Damiani, D.; Guzman Martinez, F.; Rodriguez Hoyos, O.; Rodriguez Manso, A.

    2015-01-01

    Cluster emission at pre-equilibrium stage, in heavy ion fusion reactions of 12 C and 16 O nuclei with 116 Sn, 208 Pb, 238 U are studied. the energy of the projectile nuclei was chosen at 0.25GeV, 0.5GeV and 1GeV. A cluster formation model is developed in order to calculate the cluster size. Thermodynamics of small systems was used in order to examine the cluster behavior inside the nuclear media. This model is based on considering two phases inside the compound nucleus, on one hand the nuclear media phase, and on the other hand the cluster itself. The cluster acts like an instability inside the compound nucleus, provoking an exchange of nucleons with the nuclear media through its surface. The processes were simulated using Monte Carlo methods. We obtained that the cluster emission probability shows great dependence on the cluster size. This project is aimed to implement cluster emission processes, during the pre-equilibrium stage, in the frame of CRISP code (Collaboration Rio-Sao Paulo). (Author)

  1. A comprehensive mathematical model for estimating oil drainage rate in SAGD process considering wellbore/formation coupling effect

    Science.gov (United States)

    Cheng, Linsong; Gu, Hao; Huang, Shijun

    2017-05-01

    The aim of this work is to present a comprehensive mathematical model for estimating oil drainage rate in Steam-assisted gravity drainage (SAGD) process, more importantly, wellbore/formation coupling effect is considered. Firstly, mass and heat transfer in vertical and horizontal wellbores are described briefly. Then, a function of steam chamber height is introduced and the expressions for oil drainage rate in rising and expanding steam chamber stages are derived in detail. Next, a calculation flowchart is provided and an example is given to introduce how to use the proposed method. Finally, after the mathematical model is validated, the effects of wellhead steam injection rate on simulated results are further analyzed. The results indicate that heat injection power per meter reduces gradually along the horizontal wellbore, which affects both steam chamber height and oil drainage rate in the SAGD process. In addition, when production time is the same, the calculated oil drainage rate from the new method is lower than that from Butler's method. Moreover, the paper shows that when wellhead steam injection rate is low enough, the steam chamber is not formed at the horizontal well's toe position and enhancing the wellhead steam injection rate can increase the oil drainage rate.

  2. Variability of tsunami inundation footprints considering stochastic scenarios based on a single rupture model: Application to the 2011 Tohoku earthquake

    KAUST Repository

    Goda, Katsuichiro

    2015-06-30

    The sensitivity and variability of spatial tsunami inundation footprints in coastal cities and towns due to a megathrust subduction earthquake in the Tohoku region of Japan are investigated by considering different fault geometry and slip distributions. Stochastic tsunami scenarios are generated based on the spectral analysis and synthesis method with regards to an inverted source model. To assess spatial inundation processes accurately, tsunami modeling is conducted using bathymetry and elevation data with 50 m grid resolutions. Using the developed methodology for assessing variability of tsunami hazard estimates, stochastic inundation depth maps can be generated for local coastal communities. These maps are important for improving disaster preparedness by understanding the consequences of different situations/conditions, and by communicating uncertainty associated with hazard predictions. The analysis indicates that the sensitivity of inundation areas to the geometrical parameters (i.e., top-edge depth, strike, and dip) depends on the tsunami source characteristics and the site location, and is therefore complex and highly nonlinear. The variability assessment of inundation footprints indicates significant influence of slip distributions. In particular, topographical features of the region, such as ria coast and near-shore plain, have major influence on the tsunami inundation footprints.

  3. Accuracy enhancement of thermal dispersion model in prediction of convective heat transfer for nanofluids considering the effects of particle migration

    Energy Technology Data Exchange (ETDEWEB)

    Bahiraei, Mehdi [Kermanshah University of Technology, Kermanshah (Iran, Islamic Republic of); Hosseinalipour, Seyed Mostafa [Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2013-08-15

    A thermal dispersion model is utilized for simulation of convective heat transfer of water-TiO{sub 2} nanofluid for laminar flow in circular tube. Concentration distribution at cross section of the tube was obtained considering the effects of particle migration, and this concentration distribution was applied in the numerical solution. Numerical solution was done at Reynolds numbers of 500 to 2000 and mean concentrations of 0.5 to 3%. Meanwhile, an experimental study was conducted to investigate the accuracy of the results obtained from the numerical solution. Non-uniformity of the concentration distribution increases with raising mean concentration and Reynolds number. Thereby, for mean concentration of 3%, at Reynolds numbers of 500 and 2000, the concentration from wall to center of the tube increases 2.6 and 30.9%, respectively. In the dispersion model, application of non-uniform concentration distribution improves the accuracy in prediction of the convective heat transfer coefficient in comparison with applying uniform concentration.

  4. Developing a Mathematical Model for Scheduling and Determining Success Probability of Research Projects Considering Complex-Fuzzy Networks

    Directory of Open Access Journals (Sweden)

    Gholamreza Norouzi

    2015-01-01

    Full Text Available In project management context, time management is one of the most important factors affecting project success. This paper proposes a new method to solve research project scheduling problems (RPSP containing Fuzzy Graphical Evaluation and Review Technique (FGERT networks. Through the deliverables of this method, a proper estimation of project completion time (PCT and success probability can be achieved. So algorithms were developed to cover all features of the problem based on three main parameters “duration, occurrence probability, and success probability.” These developed algorithms were known as PR-FGERT (Parallel and Reversible-Fuzzy GERT networks. The main provided framework includes simplifying the network of project and taking regular steps to determine PCT and success probability. Simplifications include (1 equivalent making of parallel and series branches in fuzzy network considering the concepts of probabilistic nodes, (2 equivalent making of delay or reversible-to-itself branches and impact of changing the parameters of time and probability based on removing related branches, (3 equivalent making of simple and complex loops, and (4 an algorithm that was provided to resolve no-loop fuzzy network, after equivalent making. Finally, the performance of models was compared with existing methods. The results showed proper and real performance of models in comparison with existing methods.

  5. Considering a point-source in a regional air pollution model; Prise en compte d`une source ponctuelle dans un modele regional de pollution atmospherique

    Energy Technology Data Exchange (ETDEWEB)

    Lipphardt, M.

    1997-06-19

    This thesis deals with the development and validation of a point-source plume model, with the aim to refine the representation of intensive point-source emissions in regional-scale air quality models. The plume is modelled at four levels of increasing complexity, from a modified Gaussian plume model to the Freiberg and Lusis ring model. Plume elevation is determined by Netterville`s plume rise model, using turbulence and atmospheric stability parameters. A model for the effect of a fine-scale turbulence on the mean concentrations in the plume is developed and integrated in the ring model. A comparison between results with and without considering micro-mixing shows the importance of this effect in a chemically reactive plume. The plume model is integrated into the Eulerian transport/chemistry model AIRQUAL, using an interface between Airqual and the sub-model, and interactions between the two scales are described. A simulation of an air pollution episode over Paris is carried out, showing that the utilization of such a sub-scale model improves the accuracy of the air quality model

  6. Where's the problem? Considering Laing and Esterson's account of schizophrenia, social models of disability, and extended mental disorder.

    Science.gov (United States)

    Cooper, Rachel

    2017-08-01

    In this article, I compare and evaluate R. D. Laing and A. Esterson's account of schizophrenia as developed in Sanity, Madness and the Family (1964), social models of disability, and accounts of extended mental disorder. These accounts claim that some putative disorders (schizophrenia, disability, certain mental disorders) should not be thought of as reflecting biological or psychological dysfunction within the afflicted individual, but instead as external problems (to be located in the family, or in the material and social environment). In this article, I consider the grounds on which such claims might be supported. I argue that problems should not be located within an individual putative patient in cases where there is some acceptable test environment in which there is no problem. A number of cases where such an argument can show that there is no internal disorder are discussed. I argue, however, that Laing and Esterson's argument-that schizophrenia is not within diagnosed patients-does not work. The problem with their argument is that they fail to show that the diagnosed women in their study function adequately in any environment.

  7. The Optimization Model for Interregional Power System Planning considering Carbon Emissions Trading and Renewable Energy Quota Mechanism

    Directory of Open Access Journals (Sweden)

    Liwei Ju

    2016-01-01

    Full Text Available In China, the rapid construction of ultra-high-voltage (UHV transmission lines promotes interregional resource optimizing configuration and interregional power system planning. This paper analyzes external environment of interregional power system planning from geographical, technical, and policy environments. Then, the paper takes the minimum system investment cost as the optimization objective and constructs the optimization model of interregional power system planning considering carbon emissions trading (CET and renewable energy quota mechanism (REQ. Finally, this paper sets base scenario, carbon emissions trading scenario, renewable energy quota mechanism scenario, and comprehensive scenario for case simulation. The results show that interregional power system planning could connect power grids in different regions, enlarge wind power consumption space, and relieve the inconformity problem between power resource and load demand. CET and REQ can increase the installed proportion of clean energy and reduce carbon dioxide emissions, but the cost of transmission lines construction and system reserve will increase correspondingly. The optimization effect of REQ on power system planning is better than CET. When they are both introduced, the power structure will reach the best, carbon dioxide emissions will achieve the minimum, and comprehensive benefits will become more balanced.

  8. A multi-period superstructure optimisation model for the optimal planning of China's power sector considering carbon dioxide mitigation

    International Nuclear Information System (INIS)

    Zhang Dongjie; Ma Linwei; Liu Pei; Zhang Lili; Li Zheng

    2012-01-01

    Power sector is the largest CO 2 emitter in China. To mitigate CO 2 emissions for the power sector is a tough task, which requires implementation of targeted carbon mitigation policies. There might be multiple forms for carbon mitigation policies and it is still unclear which one is the best for China. Applying a superstructure optimisation model for optimal planning of China's power sector built by the authors previously, which was based on real-life plants composition data of China's power sector in 2009, and could incorporate all possible actions of the power sector, including plants construction, decommission, and application of carbon capture and sequestration (CCS) on coal-fuelled plants, the implementation effects of three carbon mitigation policies were studied quantitatively, achieving a conclusion that the so-called “Surplus-Punishment and Deficit-Award” carbon tax policy is the best from the viewpoint of increasing CO 2 reduction effect and also reducing the accumulated total cost. Based on this conclusion, the corresponding relationships between CO 2 reduction objectives (including the accumulated total emissions reduction by the objective year and the annual emissions reduction in the objective year) were presented in detail. This work provides both directional and quantitative suggestions for China to make carbon mitigation policies in the future. - Highlights: ► We study the best form of carbon mitigation policy for China's power sector. ► We gain quantitative relationship between CO 2 reduction goal and carbon tax policy. ► The “Surplus-Punishment and Deficit-Award” carbon tax policy is the best. ► Nuclear and renewable power and CCS can help greatly reduce CO 2 emissions of the power sector. ► Longer objective period is preferred from the viewpoint of policy making.

  9. Mode choice models' ability to express intention to change travel behaviour considering non-compensatory rules and latent variables

    OpenAIRE

    Sanko, Nobuhiro; Morikawa, Takayuki; Kurauchi, Shinya

    2013-01-01

    Disaggregate behaviour choice models have been improved in many aspects, but they are rarely evaluated from the viewpoint of their ability to express intention to change travel behaviour. This study compared various models, including objective and latent models and compensatory and non-compensatory decision-making models. Latent models contain latent factors calculated using the LISREL (linear structural relations) model. Non-compensatory models are based on a lexicographic-semiorder heuristi...

  10. PREVIOUS SECOND TRIMESTER ABORTION

    African Journals Online (AJOL)

    PNLC

    PREVIOUS SECOND TRIMESTER ABORTION: A risk factor for third trimester uterine rupture in three ... for accurate diagnosis of uterine rupture. KEY WORDS: Induced second trimester abortion - Previous uterine surgery - Uterine rupture. ..... scarred uterus during second trimester misoprostol- induced labour for a missed ...

  11. Mode choice models' ability to express intention to change travel behaviour considering non-compensatory rules and latent variables

    Directory of Open Access Journals (Sweden)

    Nobuhiro Sanko

    2013-03-01

    Full Text Available Disaggregate behaviour choice models have been improved in many aspects, but they are rarely evaluated from the viewpoint of their ability to express intention to change travel behaviour. This study compared various models, including objective and latent models and compensatory and non-compensatory decision-making models. Latent models contain latent factors calculated using the LISREL (linear structural relations model. Non-compensatory models are based on a lexicographic-semiorder heuristic. This paper proposes ‘probability increment’ and ‘joint probability increment’ as indicators for evaluating the ability of these models to express intention to change travel behaviour. The application to commuting travel data in the Chukyo metropolitan area in Japan showed that the appropriate non-compensatory and latent models outperform other models.

  12. A Comprehensive Prediction Model of Hydraulic Extended-Reach Limit Considering the Allowable Range of Drilling Fluid Flow Rate in Horizontal Drilling.

    Science.gov (United States)

    Li, Xin; Gao, Deli; Chen, Xuyue

    2017-06-08

    Hydraulic extended-reach limit (HERL) model of horizontal extended-reach well (ERW) can predict the maximum measured depth (MMD) of the horizontal ERW. The HERL refers to the well's MMD when drilling fluid cannot be normally circulated by drilling pump. Previous model analyzed the following two constraint conditions, drilling pump rated pressure and rated power. However, effects of the allowable range of drilling fluid flow rate (Q min  ≤ Q ≤ Q max ) were not considered. In this study, three cases of HERL model are proposed according to the relationship between allowable range of drilling fluid flow rate and rated flow rate of drilling pump (Q r ). A horizontal ERW is analyzed to predict its HERL, especially its horizontal-section limit (L h ). Results show that when Q min  ≤ Q r  ≤ Q max (Case I), L h depends both on horizontal-section limit based on rated pump pressure (L h1 ) and horizontal-section limit based on rated pump power (L h2 ); when Q min  < Q max  < Q r (Case II), L h is exclusively controlled by L h1 ; while L h is only determined by L h2 when Q r  < Q min  < Q max (Case III). Furthermore, L h1 first increases and then decreases with the increase in drilling fluid flow rate, while L h2 keeps decreasing as the drilling fluid flow rate increases. The comprehensive model provides a more accurate prediction on HERL.

  13. A dynamic capacity degradation model and its applications considering varying load for a large format Li-ion battery

    International Nuclear Information System (INIS)

    Ouyang, Minggao; Feng, Xuning; Han, Xuebing; Lu, Languang; Li, Zhe; He, Xiangming

    2016-01-01

    Highlights: • A dynamic capacity degradation model for large format Li-ion battery is proposed. • The change of the model parameters directly link with the degradation mechanisms. • The model can simulate the fading behavior of Li-ion battery under varying loads. • The model can help evaluate the longevity of a battery system under specific load. • The model can help predict the evolution of cell variations within a battery pack. - Abstract: The capacity degradation of the lithium ion battery should be well predicted during battery system design. Therefore, high-fidelity capacity degradation models that are suitable for the task of capacity prediction are required. This paper proposes a novel capacity degradation model that can simulate the degradation dynamics under varying working conditions for large-format lithium ion batteries. The degradation model is built based on a mechanistic and prognostic model (MPM) whose parameters are closely linked with the degradation mechanisms of lithium ion batteries. Chemical kinetics was set to drive the parameters of the MPM to change as capacity degradation continues. With the dynamic parameters of the MPM, the capacity predicted by the degradation model decreases as the cycle continues. Accelerated aging tests were conducted on three types of commercial lithium ion batteries to calibrate the capacity degradation model. The good fit with the experimental data indicates that the model can capture the degradation mechanisms well for different types of commercial lithium ion batteries. Furthermore, the calibrated model can be used to (1) evaluate the longevity of a battery system under a specific working load and (2) predict the evolution of cell variations within a battery pack when different cell works at different conditions. Correlated applications are discussed using the calibrated degradation model.

  14. A new lattice hydrodynamic model based on control method considering the flux change rate and delay feedback signal

    Science.gov (United States)

    Qin, Shunda; Ge, Hongxia; Cheng, Rongjun

    2018-02-01

    In this paper, a new lattice hydrodynamic model is proposed by taking delay feedback and flux change rate effect into account in a single lane. The linear stability condition of the new model is derived by control theory. By using the nonlinear analysis method, the mKDV equation near the critical point is deduced to describe the traffic congestion. Numerical simulations are carried out to demonstrate the advantage of the new model in suppressing traffic jam with the consideration of flux change rate effect in delay feedback model.

  15. An improved Armstrong-Frederick-Type Plasticity Model for Stable Cyclic Stress-Strain Responses Considering Nonproportional Hardening

    Science.gov (United States)

    Li, Jing; Zhang, Zhong-ping; Li, Chun-wang

    2018-03-01

    This paper modified an Armstrong-Frederick-type plasticity model for investigating the stable cyclic deformation behavior of metallic materials with different sensitivity to nonproportional loadings. In the modified model, the nonproportionality factor and nonproportional cyclic hardening coefficient coupled with the Jiang-Sehitoglu incremental plasticity model were used to estimate the stable stress-strain responses of the two materials (1045HR steel and 304 stainless steel) under various tension-torsion strain paths. A new equation was proposed to calculate the nonproportionality factor on the basis of the minimum normal strain range. Procedures to determine the minimum normal strain range were presented for general multiaxial loadings. Then, the modified model requires only the cyclic strain hardening exponent and cyclic strength coefficient to determine the material constants. It is convenient for predicting the stable stress-strain responses of materials in engineering application. Comparisons showed that the modified model can reflect the effect of nonproportional cyclic hardening well.

  16. Numerical modelling of ground vibration caused by elevated high-speed railway lines considering structure-soil-structure interaction

    DEFF Research Database (Denmark)

    Bucinskas, Paulius; Andersen, Lars Vabbersgaard; Persson, Kent

    2016-01-01

    densely populated urban areas with the collateral effect of increased noise and vibrations levels. This paper aims to quantify the vibrations levels in the area surrounding an elevated railway line built as a multi-span bridge structure. The proposed model employs finite-element analysis to model......-space. The paper analyses the effects of structure-soil-structure interaction on the dynamic behaviour of the surrounding soil surface. The effects of different soil stratification and material properties as well as different train speeds are assessed. Finally, the drawbacks of simplifying the numerical model...

  17. Interval Optimization Model Considering Terrestrial Ecological Impacts for Water Rights Transfer from Agriculture to Industry in Ningxia, China

    OpenAIRE

    Sun, Lian; Li, Chunhui; Cai, Yanpeng; Wang, Xuan

    2017-01-01

    In this study, an interval optimization model is developed to maximize the benefits of a water rights transfer system that comprises industry and agriculture sectors in the Ningxia Hui Autonomous Region in China. The model is subjected to a number of constraints including water saving potential from agriculture and ecological groundwater levels. Ecological groundwater levels serve as performance indicators of terrestrial ecology. The interval method is applied to present the uncertainty of pa...

  18. The Importance of Tree Height in Estimating Individual Tree Biomass While Considering Errors in Measurements and Allometric Models

    OpenAIRE

    Phalla, Thuch; Ota, Tetsuji; Mizoue, Nobuya; Kajisa, Tsuyoshi; Yoshida, Shigejiro; Vuthy, Ma; Heng, Sokh

    2018-01-01

    This study evaluated the uncertainty of individual tree biomass estimated by allometric models by both including and excluding tree height independently. Using two independent sets of measurements on the same trees, the errors in the measurement of diameter at breast height and tree height were quantified, and the uncertainty of individual tree biomass estimation caused by errors in measurement was calculated. For both allometric models, the uncertainties of the individual tree biomass estima...

  19. Study on Complex Advertising and Price Competition Dual-Channel Supply Chain Models Considering the Overconfidence Manufacturer

    Directory of Open Access Journals (Sweden)

    Junhai Ma

    2016-01-01

    Full Text Available In order to explore how the manufacturers make decisions when two manufacturers compete for local advertising investment, we examine two noncooperative models (Stackelberg and Nash game and propose a cost sharing contract to investigate channel competition of dual-channel supply chain. The dominant power between manufacturer and retailer and the effect of channel competition strategy on price are mainly discussed. In addition, dynamic system concepts are integrated into Stackelberg game model based on bounded rational mechanism. We analyze the local stability and find that the stability level of the dual-channel supply chains depends crucially on the price adjustment speed, the level of demand uncertainty, and the risk preference. The outcome shows that, under the master-slave game model, the profits of manufacturers are greater than that under decentralized decision-making mode, and the profits of retailers under master-slave game model are less than that under decentralized decision-making mode. The profits of manufacturers and retailers in the stable region are greater than that in unstable region. Finally, the delay feedback control method is utilized and effectively controls the chaotic behavior of dual-channel supply chain model. The results have theoretical and practical significance for the game models in terms of advertising and price competition.

  20. An improved quasi-steady aerodynamic model for insect wings that considers movement of the center of pressure.

    Science.gov (United States)

    Han, Jong-Seob; Kim, Joong-Kwan; Chang, Jo Won; Han, Jae-Hung

    2015-07-30

    A quasi-steady aerodynamic model in consideration of the center of pressure (C.P.) was developed for insect flight. A dynamically scaled-up robotic hawkmoth wing was used to obtain the translational lift, drag, moment and rotational force coefficients. The translational force coefficients were curve-fitted with respect to the angles of attack such that two coefficients in the Polhamus leading-edge suction analogy model were obtained. The rotational force coefficient was also compared to that derived by the standard Kutta-Joukowski theory. In order to build the accurate pitching moment model, the locations of the C.Ps. and its movements depending on the pitching velocity were investigated in detail. We found that the aerodynamic moment model became suitable when the rotational force component was assumed to act on the half-chord. This implies that the approximation borrowed from the conventional airfoil concept, i.e., the 'C.P. at the quarter-chord' may lead to an incorrect moment prediction. In the validation process, the model showed excellent time-course force and moment estimations in comparison with the robotic wing measurement results. A fully nonlinear multibody flight dynamic simulation was conducted to check the effect of the traveling C.P. on the overall flight dynamics. This clearly showed the importance of an accurate aerodynamic moment model.

  1. Simulating bi-directional pedestrian flow in a cellular automaton model considering the body-turning behavior

    Science.gov (United States)

    Jin, Cheng-Jie; Jiang, Rui; Yin, Jun-Lin; Dong, Li-Yun; Li, Dawei

    2017-09-01

    In the experiments of bi-directional pedestrian flow, it is often observed that pedestrians turn their bodies and change from walking straight to walking sideways, in order to mitigate or avoid the conflicts with opposite walking ones. When these conflicts disappear, pedestrians restore and walk straight again. In the turning states, the forward velocities of pedestrians are not affected. In order to simulate this body-turning behavior, we use a cellular automaton (CA) model named ITP model, which has been proposed before. But the occupied area of one pedestrian is set as 0.4 m∗0.2 m. After the introduction of new rules of turnings and restorations, the pedestrians become more intelligent and flexible during the lane formation process, and some improvements of the fundamental diagram of pedestrian flow can be found. The simulation results of two different scenarios under open boundary conditions are also presented, and compared with the experimental data. It is shown that the new model performs much better than the original model in various tests, which further confirms the validity of the new rules. We think this approach is one useful contribution to the pedestrian flow modeling.

  2. A production planning model considering uncertain demand using two-stage stochastic programming in a fresh vegetable supply chain context.

    Science.gov (United States)

    Mateo, Jordi; Pla, Lluis M; Solsona, Francesc; Pagès, Adela

    2016-01-01

    Production planning models are achieving more interest for being used in the primary sector of the economy. The proposed model relies on the formulation of a location model representing a set of farms susceptible of being selected by a grocery shop brand to supply local fresh products under seasonal contracts. The main aim is to minimize overall procurement costs and meet future demand. This kind of problem is rather common in fresh vegetable supply chains where producers are located in proximity either to processing plants or retailers. The proposed two-stage stochastic model determines which suppliers should be selected for production contracts to ensure high quality products and minimal time from farm-to-table. Moreover, Lagrangian relaxation and parallel computing algorithms are proposed to solve these instances efficiently in a reasonable computational time. The results obtained show computational gains from our algorithmic proposals in front of the usage of plain CPLEX solver. Furthermore, the results ensure the competitive advantages of using the proposed model by purchase managers in the fresh vegetables industry.

  3. Nonlinear density wave investigation for an extended car-following model considering driver’s memory and jerk

    Science.gov (United States)

    Jin, Zhizhan; Li, Zhipeng; Cheng, Rongjun; Ge, Hongxia

    2018-01-01

    Based on the two velocity difference model (TVDM), an extended car-following model is developed to investigate the effect of driver’s memory and jerk on traffic flow in this paper. By using linear stability analysis, the stability conditions are derived. And through nonlinear analysis, the time-dependent Ginzburg-Landau (TDGL) equation and the modified Korteweg-de Vries (mKdV) equation are obtained, respectively. The mKdV equation is constructed to describe the traffic behavior near the critical point. The evolution of traffic congestion and the corresponding energy consumption are discussed. Numerical simulations show that the improved model is found not only to enhance the stability of traffic flow, but also to depress the energy consumption, which are consistent with the theoretical analysis.

  4. Effect of Borehole Material on Analytical Solutions of the Heat Transfer Model of Ground Heat Exchangers Considering Groundwater Flow

    Directory of Open Access Journals (Sweden)

    Sangwoo Park

    2016-04-01

    Full Text Available Groundwater flow is one of the most important factors for the design of a ground heat exchanger (GHEX since the thermal environment of the ground around the buried GHEX is significantly affected by heat convection due to the groundwater flow. Several preceding studies have been conducted to develop analytical solutions to the heat transfer model of GHEX with consideration of groundwater flow. One of these solutions is the combined heat transfer model of conduction and convection. However, the developed combined analytical models are inapplicable to all of the configurations of ordinary GHEXs because these solutions assume that the inner part of the borehole is thermally inert or consists of the same material as that of the surrounding ground. In this paper, the applicability of the combined solid cylindrical heat source model, which is the most suitable to energy piles until now, was evaluated by performing a series of numerical analyses. In the numerical analysis, the inner part of the borehole was modeled as two different materials (i.e., permeable ground formation and impermeable fill such as concrete to evaluate applicability of the analytical solution along with different diameter-length (D/L ratios of borehole. In a small value of the D/L ratio, the analytical solution to the combined heat transfer model is in good agreement with the result of numerical analysis. On the other hand, when increasing the D/L ratio, the analytical solution significantly overestimates the effect of groundwater flow on the heat transfer of GHEXs because the analytical solution disregards the existence of the impermeable region in the borehole. Consequently, such tendency is more critical in the GHEX with a large D/L ratio such as large-diameter energy piles.

  5. Integer Optimization Model for a Logistic System based on Location-Routing Considering Distance and Chosen Route

    Science.gov (United States)

    Mulyasari, Joni; Mawengkang, Herman; Efendi, Syahril

    2018-02-01

    In a distribution network it is important to decide the locations of facilities that impacts not only the profitability of an organization but the ability to serve customers.Generally the location-routing problem is to minimize the overall cost by simultaneously selecting a subset of candidate facilities and constructing a set of delivery routes that satisfy some restrictions. In this paper we impose restriction on the route that should be passed for delivery. We use integer programming model to describe the problem. A feasible neighbourhood search is proposed to solve the result model.

  6. Empirically-based modeling and mapping to consider the co-occurrence of ecological receptors and stressors

    Science.gov (United States)

    Part of the ecological risk assessment process involves examining the potential for environmental stressors and ecological receptors to co-occur across a landscape. In this study, we introduce a Bayesian joint modeling framework for use in evaluating and mapping the co-occurrence...

  7. Temporal dynamics of interference in Simon and Eriksen tasks considered within the context of a dual-process model.

    NARCIS (Netherlands)

    Mansfield, K.L.; van der Molen, M.W.; Falkenstein, M.; van Boxtel, G.J.M.

    2013-01-01

    Behavioral and brain potential measures were employed to compare interference in Eriksen and Simon tasks. Assuming a dual-process model of interference elicited in speeded response tasks, we hypothesized that only lateralized stimuli in the Simon task induce fast S–R priming via direct unconditional

  8. Linear Modeling of the Three-Phase Diode Front-Ends with Reduced Capacitance Considering the Continuous Conduction Mode

    DEFF Research Database (Denmark)

    Máthé, Lászlo; Yang, Feng; Wang, Dong

    2016-01-01

    for the entire drive systems have to be designed. A linearization and simplification to single phase model can be performed; however, when inductance is present at the grid side its performance is not satisfactory. The problem is mainly caused by neglecting the continuous conduction mode of the rectifier...

  9. A numerical formulation using unstructured grids for modeling two-phase flows in porous media considering heterogeneities and capillarity effects

    International Nuclear Information System (INIS)

    Hurtado, F.S.V.; Maliska, C.R.

    2005-01-01

    This paper briefly describes a two-dimensional numerical formulation using unstructured grids, developed for simulating two-phase immiscible displacements in porous media. The Element-based Finite Volume Method (EbFVM) is used for discretizing the model differential equations. (authors)

  10. A numerical formulation using unstructured grids for modeling two-phase flows in porous media considering heterogeneities and capillarity effects

    Energy Technology Data Exchange (ETDEWEB)

    Hurtado, F.S.V.; Maliska, C.R. [Santa Catarina Federal Univ., Computational Fluid Dynamics Lab., Mechanical Engineering Dept., Florianopolis, SC (Brazil)

    2005-07-01

    This paper briefly describes a two-dimensional numerical formulation using unstructured grids, developed for simulating two-phase immiscible displacements in porous media. The Element-based Finite Volume Method (EbFVM) is used for discretizing the model differential equations. (authors)

  11. Predictive Models for Tomato Spotted Wilt Virus Spread Dynamics, Considering Frankliniella occidentalis Specific Life Processes as Influenced by the Virus.

    Directory of Open Access Journals (Sweden)

    Pamella Akoth Ogada

    Full Text Available Several models have been studied on predictive epidemics of arthropod vectored plant viruses in an attempt to bring understanding to the complex but specific relationship between the three cornered pathosystem (virus, vector and host plant, as well as their interactions with the environment. A large body of studies mainly focuses on weather based models as management tool for monitoring pests and diseases, with very few incorporating the contribution of vector's life processes in the disease dynamics, which is an essential aspect when mitigating virus incidences in a crop stand. In this study, we hypothesized that the multiplication and spread of tomato spotted wilt virus (TSWV in a crop stand is strongly related to its influences on Frankliniella occidentalis preferential behavior and life expectancy. Model dynamics of important aspects in disease development within TSWV-F. occidentalis-host plant interactions were developed, focusing on F. occidentalis' life processes as influenced by TSWV. The results show that the influence of TSWV on F. occidentalis preferential behaviour leads to an estimated increase in relative acquisition rate of the virus, and up to 33% increase in transmission rate to healthy plants. Also, increased life expectancy; which relates to improved fitness, is dependent on the virus induced preferential behaviour, consequently promoting multiplication and spread of the virus in a crop stand. The development of vector-based models could further help in elucidating the role of tri-trophic interactions in agricultural disease systems. Use of the model to examine the components of the disease process could also boost our understanding on how specific epidemiological characteristics interact to cause diseases in crops. With this level of understanding we can efficiently develop more precise control strategies for the virus and the vector.

  12. Predictive Models for Tomato Spotted Wilt Virus Spread Dynamics, Considering Frankliniella occidentalis Specific Life Processes as Influenced by the Virus.

    Science.gov (United States)

    Ogada, Pamella Akoth; Moualeu, Dany Pascal; Poehling, Hans-Michael

    2016-01-01

    Several models have been studied on predictive epidemics of arthropod vectored plant viruses in an attempt to bring understanding to the complex but specific relationship between the three cornered pathosystem (virus, vector and host plant), as well as their interactions with the environment. A large body of studies mainly focuses on weather based models as management tool for monitoring pests and diseases, with very few incorporating the contribution of vector's life processes in the disease dynamics, which is an essential aspect when mitigating virus incidences in a crop stand. In this study, we hypothesized that the multiplication and spread of tomato spotted wilt virus (TSWV) in a crop stand is strongly related to its influences on Frankliniella occidentalis preferential behavior and life expectancy. Model dynamics of important aspects in disease development within TSWV-F. occidentalis-host plant interactions were developed, focusing on F. occidentalis' life processes as influenced by TSWV. The results show that the influence of TSWV on F. occidentalis preferential behaviour leads to an estimated increase in relative acquisition rate of the virus, and up to 33% increase in transmission rate to healthy plants. Also, increased life expectancy; which relates to improved fitness, is dependent on the virus induced preferential behaviour, consequently promoting multiplication and spread of the virus in a crop stand. The development of vector-based models could further help in elucidating the role of tri-trophic interactions in agricultural disease systems. Use of the model to examine the components of the disease process could also boost our understanding on how specific epidemiological characteristics interact to cause diseases in crops. With this level of understanding we can efficiently develop more precise control strategies for the virus and the vector.

  13. Developing an ANN model to simulate ASTM C1012-95 test considering different cement types and different pozzolanic additives

    Directory of Open Access Journals (Sweden)

    O.A. Hodhod

    2013-04-01

    In this research a study is presented to build a model by ANN equivalent to ASTM C1012-95. The input parameter was obtained from 16 different mortars according to ASTM C1012-95. Plain Portland cement mortars, mortars with cement combined with fly ash (FA, and mortars with cement combined with slag (GGBFS were tested by using ASTM C1012-95. Four cements, two ratio of FA, and one GGBFS were obtained from the literature. ASTM C1012-95 modeling techniques can help us understand the influence of aggressive environments on the concrete performance more readily, faster, and accurately. Such an understanding improves the decision making process in every stage of construction and maintenance and will help in better administration of resources.

  14. An Optimization Scheduling Model for Wind Power and Thermal Power with Energy Storage System considering Carbon Emission Trading

    Directory of Open Access Journals (Sweden)

    Huan-huan Li

    2015-01-01

    Full Text Available Wind power has the characteristics of randomness and intermittence, which influences power system safety and stable operation. To alleviate the effect of wind power grid connection and improve power system’s wind power consumptive capability, this paper took emission trading and energy storage system into consideration and built an optimization model for thermal-wind power system and energy storage systems collaborative scheduling. A simulation based on 10 thermal units and wind farms with 2800 MW installed capacity verified the correctness of the models put forward by this paper. According to the simulation results, the introduction of carbon emission trading can improve wind power consumptive capability and cut down the average coal consumption per unit of power. The introduction of energy storage system can smooth wind power output curve and suppress power fluctuations. The optimization effects achieve the best when both of carbon emission trading and energy storage system work at the same time.

  15. An Integer Programming Model For Solving Heterogeneous Vehicle Routing Problem With Hard Time Window considering Service Choice

    Science.gov (United States)

    Susilawati, Enny; Mawengkang, Herman; Efendi, Syahril

    2018-01-01

    Generally a Vehicle Routing Problem with time windows (VRPTW) can be defined as a problem to determine the optimal set of routes used by a fleet of vehicles to serve a given set of customers with service time restrictions; the objective is to minimize the total travel cost (related to the travel times or distances) and operational cost (related to the number of vehicles used). In this paper we address a variant of the VRPTW in which the fleet of vehicle is heterogenic due to the different size of demand from customers. The problem, called Heterogeneous VRP (HVRP) also includes service levels. We use integer programming model to describe the problem. A feasible neighbourhood approach is proposed to solve the model.

  16. A variation reduction allocation model for quality improvement to minimize investment and quality costs by considering suppliers’ learning curve

    Science.gov (United States)

    Rosyidi, C. N.; Jauhari, WA; Suhardi, B.; Hamada, K.

    2016-02-01

    Quality improvement must be performed in a company to maintain its product competitiveness in the market. The goal of such improvement is to increase the customer satisfaction and the profitability of the company. In current practice, a company needs several suppliers to provide the components in assembly process of a final product. Hence quality improvement of the final product must involve the suppliers. In this paper, an optimization model to allocate the variance reduction is developed. Variation reduction is an important term in quality improvement for both manufacturer and suppliers. To improve suppliers’ components quality, the manufacturer must invest an amount of their financial resources in learning process of the suppliers. The objective function of the model is to minimize the total cost consists of investment cost, and quality costs for both internal and external quality costs. The Learning curve will determine how the employee of the suppliers will respond to the learning processes in reducing the variance of the component.

  17. A cooperative reduction model for regional air pollution control in China that considers adverse health effects and pollutant reduction costs.

    Science.gov (United States)

    Xie, Yujing; Zhao, Laijun; Xue, Jian; Hu, Qingmi; Xu, Xiang; Wang, Hongbo

    2016-12-15

    How to effectively control severe regional air pollution has become a focus of global concern recently. The non-cooperative reduction model (NCRM) is still the main air pollution control pattern in China, but it is both ineffective and costly, because each province must independently fight air pollution. Thus, we proposed a cooperative reduction model (CRM), with the goal of maximizing the reduction in adverse health effects (AHEs) at the lowest cost by encouraging neighboring areas to jointly control air pollution. CRM has two parts: a model of optimal pollutant removal rates using two optimization objectives (maximizing the reduction in AHEs and minimizing pollutant reduction cost) while meeting the regional pollution control targets set by the central government, and a model that allocates the cooperation benefits (i.e., health improvement and cost reduction) among the participants according to their contributions using the Shapley value method. We applied CRM to the case of sulfur dioxide (SO 2 ) reduction in Yangtze River Delta region. Based on data from 2003 to 2013, and using mortality due to respiratory and cardiovascular diseases as the health endpoints, CRM saves 437 more lives than NCRM, amounting to 12.1% of the reduction under NCRM. CRM also reduced costs by US $65.8×10 6 compared with NCRM, which is 5.2% of the total cost of NCRM. Thus, CRM performs significantly better than NCRM. Each province obtains significant benefits from cooperation, which can motivate them to actively cooperate in the long term. A sensitivity analysis was performed to quantify the effects of parameter values on the cooperation benefits. Results shown that the CRM is not sensitive to the changes in each province's pollutant carrying capacity and the minimum pollutant removal capacity, but sensitive to the maximum pollutant reduction capacity. Moreover, higher cooperation benefits will be generated when a province's maximum pollutant reduction capacity increases. Copyright

  18. Interval Optimization Model Considering Terrestrial Ecological Impacts for Water Rights Transfer from Agriculture to Industry in Ningxia, China.

    Science.gov (United States)

    Sun, Lian; Li, Chunhui; Cai, Yanpeng; Wang, Xuan

    2017-06-14

    In this study, an interval optimization model is developed to maximize the benefits of a water rights transfer system that comprises industry and agriculture sectors in the Ningxia Hui Autonomous Region in China. The model is subjected to a number of constraints including water saving potential from agriculture and ecological groundwater levels. Ecological groundwater levels serve as performance indicators of terrestrial ecology. The interval method is applied to present the uncertainty of parameters in the model. Two scenarios regarding dual industrial development targets (planned and unplanned ones) are used to investigate the difference in potential benefits of water rights transfer. Runoff of the Yellow River as the source of water rights fluctuates significantly in different years. Thus, compensation fees for agriculture are calculated to reflect the influence of differences in the runoff. Results show that there are more available water rights to transfer for industrial development. The benefits are considerable but unbalanced between buyers and sellers. The government should establish a water market that is freer and promote the interest of agriculture and farmers. Though there has been some success of water rights transfer, the ecological impacts and the relationship between sellers and buyers require additional studies.

  19. Weighted Time-Band Approximation Model for Flight Operations Recovery considering Simplex Group Cycle Approaches in China

    Directory of Open Access Journals (Sweden)

    Haiwen Xu

    2016-01-01

    Full Text Available The time-band approximation model for flight operations recovery following disruption (Bard, Yu, Arguello, IIE Transactions, 33, 931–947, 2001 is constructed by partitioning the recovery period into time bands and by approximating the delay costs associated with the possible flight connections. However, for disruptions occurring in a hub-and-spoke network, a large number of possible flight connections are constructed throughout the entire flight schedule, so as to obtain the approximate optimal. In this paper, we show the application of the simplex group cycle approach to hub-and-spoke airlines in China, along with the related weighted threshold necessary for controlling the computation time and the flight disruption scope and depth. Subsequently, we present the weighted time-band approximation model for flight operations recovery, which incorporates the simplex group cycle approach. Simple numerical experiments using actual data from Air China show that the weighted time-band approximation model is feasible, and the results of stochastic experiments using actual data from Sichuan Airlines show that the flight disruption and computation time are controlled by the airline operations control center, which aims to achieve a balance between the flight disruption scope and depth, computation time, and recovery value.

  20. Considering High School Students’ Experience in Asynchronous and Synchronous Distance Learning Environments: QoE Prediction Model

    Directory of Open Access Journals (Sweden)

    Toni Malinovski

    2014-09-01

    Full Text Available Early identification of relevant factors that influence students’ experiences is vitally important to the educational process since they play an important role in learning outcomes. The purpose of this study is to determine underlying constructs that predict high school students’ subjective experience and quality expectations during asynchronous and synchronous distance education activities, in a form of quality of experience (QoE. One hundred and fifty-eight students from different high schools participated in several asynchronous and synchronous learning sessions and provided relevant feedback with comparable opinions regarding different conditions. Structural equation modeling was used as an analytical procedure during data analysis which led to a QoE prediction model that identified relevant factors influencing students’ subjective QoE. The results demonstrated no significant difference related to students’ behavior and expectations during both distance education methods. Additionally, this study revealed that students’ QoE in any situation was mainly determined by motivational factors (intrinsic and extrinsic and moderately influenced by ease of use during synchronous or quality of content during asynchronous activities. We also found moderate support between technical performance and students’ QoE in both learning environments. However, opposed to existing technology acceptance models that stress the importance of attitude towards use, high school students’ attitude failed to predict their QoE.

  1. Zooplankton mortality in 3D ecosystem modelling considering variable spatial–temporal fish consumptions in the North Sea

    DEFF Research Database (Denmark)

    Maar, Marie; Rindorf, Anna; Møller, Eva Friis

    2014-01-01

    ), Atlantic mackerel (Scomber scombrus), sandeel (Ammodytidae) and European sprat (Sprattus sprattus) was derived from quarterly scientific trawl surveys and Danish commercial catches. Spatio-temporal indices of mortality were created based on the estimated biomasses and ingestion rates from the literature...... fish spawning distribution information and iii) physics (ocean currents and temperatures) for the region and situation of interest. The fish index seems promising as a realistic mortality term for lower trophic levels in 3D ecosystem models in areas with available data on fish stocks to improve...

  2. Optimizing operation costs of the heating system of a household using model predictive control considering a local PV installation

    DEFF Research Database (Denmark)

    Koch-Ciobotaru, Cosmin; Isleifsson, Fridrik Rafn; Gehrke, Oliver

    2012-01-01

    the effects of their large penetration in the distribution grid and reduces overloading the grid capacity, which is an increasing problem for the power system. The controller uses 24 hour prediction data for the ambient temperature, the solar irradiance, and for the PV output power. Simulation results......This paper presents a model predictive controller developed in order to minimize the cost of grid energy consumption and maximize the amount of energy consumed from a local photovoltaic (PV) installation. The usage of as much locally produced renewable energy sources (RES) as possible, diminishes...

  3. Multi-response optimization and modeling of trim cut WEDM operation of commercially pure titanium (CPTi considering multiple user's preferences

    Directory of Open Access Journals (Sweden)

    Rupesh Chalisgaonkar

    2015-06-01

    Full Text Available In this research work, development of a multi response optimization technique has been undertaken, using traditional utility method in conjunction with the weight assignment concept (for multiple customer's priorities in trim cut wire electrical discharge machining (WEDM. Pure titanium has been selected as work material for experimentation. The effect of key process parameters such a wire type (zinc coated and uncoated brass wire, pulse on time (TON, pulse off time (TOFF, peak current (IP, wire feed (WF, servo voltage (SV and wire offset (WOFF were investigated on material removal rate (MRR, surface roughness and wire weight consumption (eroded weight of wire after machining in finish cut WEDM operation. Two different types of wire electrodes were taken for experimental research (uncoated, zinc coated. Further, the variation of the MRR was modeled semi-empirically through dimensional analysis. The developed model is mechanistic, as it can be used by the machinists to predict the MRR over a wide range of input parameters. The optimization of multiple responses has been done for satisfying the priorities of multiple users, in contrast to the traditional multi-response techniques where the optimized process setting is realized without giving any attention to the priorities of different users.

  4. Virtual Inertia Control-Based Model Predictive Control for Microgrid Frequency Stabilization Considering High Renewable Energy Integration

    Directory of Open Access Journals (Sweden)

    Thongchart Kerdphol

    2017-05-01

    Full Text Available Renewable energy sources (RESs, such as wind and solar generations, equip inverters to connect to the microgrids. These inverters do not have any rotating mass, thus lowering the overall system inertia. This low system inertia issue could affect the microgrid stability and resiliency in the situation of uncertainties. Today’s microgrids will become unstable if the capacity of RESs become larger and larger, leading to the weakening of microgrid stability and resilience. This paper addresses a new concept of a microgrid control incorporating a virtual inertia system based on the model predictive control (MPC to emulate virtual inertia into the microgrid control loop, thus stabilizing microgrid frequency during high penetration of RESs. The additional controller of virtual inertia is applied to the microgrid, employing MPC with virtual inertia response. System modeling and simulations are carried out using MATLAB/Simulink® software. The simulation results confirm the superior robustness and frequency stabilization effect of the proposed MPC-based virtual inertia control in comparison to the fuzzy logic system and conventional virtual inertia control in a system with high integration of RESs. The proposed MPC-based virtual inertia control is able to improve the robustness and frequency stabilization of the microgrid effectively.

  5. Quantitative Measurement of Eyestrain on 3D Stereoscopic Display Considering the Eye Foveation Model and Edge Information

    Directory of Open Access Journals (Sweden)

    Hwan Heo

    2014-05-01

    Full Text Available We propose a new method for measuring the degree of eyestrain on 3D stereoscopic displays using a glasses-type of eye tracking device. Our study is novel in the following four ways: first, the circular area where a user’s gaze position exists is defined based on the calculated gaze position and gaze estimation error. Within this circular area, the position where edge strength is maximized can be detected, and we determine this position as the gaze position that has a higher probability of being the correct one. Based on this gaze point, the eye foveation model is defined. Second, we quantitatively evaluate the correlation between the degree of eyestrain and the causal factors of visual fatigue, such as the degree of change of stereoscopic disparity (CSD, stereoscopic disparity (SD, frame cancellation effect (FCE, and edge component (EC of the 3D stereoscopic display using the eye foveation model. Third, by comparing the eyestrain in conventional 3D video and experimental 3D sample video, we analyze the characteristics of eyestrain according to various factors and types of 3D video. Fourth, by comparing the eyestrain with or without the compensation of eye saccades movement in 3D video, we analyze the characteristics of eyestrain according to the types of eye movements in 3D video. Experimental results show that the degree of CSD causes more eyestrain than other factors.

  6. Pricing Models for Dual-channel Reverse Supply Chain Considering Regional Differences under “Internet Recycling” Mode in China

    Science.gov (United States)

    Wu, Di; Li, Peng; Chen, Juhong

    2018-01-01

    In recent years, the Internet technology has been deeply influencing recycling industry to make it more intelligent and interconnected. However, most existing papers on “Internet Recycling” neglected the problem of pricing strategy under online and offline channels for different levels of recyclers. Moreover, the effect of regional differences has been emphasized a lot in dual-channel forward supply chain, but recycling field has seldom been concerned about it. In this paper, a recycling system consisting of one recycling center and several third-party recyclers (TPR) was investigated based on traditional mode and dual-channel mode. The dual-channel reverse supply chain model is transformed from traditional mode by the introduction of online channel. It involves two recycling modes, as recycling centre for online recovery and “Recycling center+TPR” for offline recovery. By establishing pricing strategies based on Stackelberg game model, the impacts of regional differences were analysed. Finally, numerical analysis was given to illustrate the effectiveness of the pricing mechanisms and strategies.

  7. A combination Kalman filter approach for State of Charge estimation of lithium-ion battery considering model uncertainty

    International Nuclear Information System (INIS)

    Li, Yanwen; Wang, Chao; Gong, Jinfeng

    2016-01-01

    An accurate battery State of Charge estimation plays an important role in battery electric vehicles. This paper makes two contributions to the existing literature. (1) A recursive least squares method with fuzzy adaptive forgetting factor has been presented to update the model parameters close to the real value more quickly. (2) The statistical information of the innovation sequence obeying chi-square distribution has been introduced to identify model uncertainty, and a novel combination algorithm of strong tracking unscented Kalman filter and adaptive unscented Kalman filter has been developed to estimate SOC (State of Charge). Experimental results indicate that the novel algorithm has a good performance in estimating the battery SOC against initial SOC errors and voltage sensor drift. A comparison with the unscented Kalman filter-based algorithms and adaptive unscented Kalman filter-based algorithms shows that the proposed SOC estimation method has better accuracy, robustness and convergence behavior. - Highlights: • Recursive least squares method with fuzzy adaptive forgetting factor is presented. • The innovation obeying chi-square distribution is used to identify uncertainty. • A combination Karman filter approach for State of Charge estimation is presented. • The performance of the proposed method is verified by comparison results.

  8. Determination of expander apparatus displacements and contact pressures on the mucosa using FEM modelling considering mandibular asymmetries.

    Science.gov (United States)

    Braga, Iracema Utsch; Rocha, Daniel Neves; Utsch, Ricardo Luiz; Las Casas, Estevam Barbosa; Andrade, Roberto Márcio; Jorge, Renato Natal; Braga, Rafael Utsch

    2013-01-01

    This paper presents a method for prediction of forces and displacements in the expansion screw of a modified mandibular Schwarz appliance and the contact pressure distributions on the mucosa during malocclusions treatment. A 3D finite element biomechanical model of the complete mandible-mucosa-apparatus set was built using computerised tomographic images of a patient's mandible and constructive solid geometry by computer software. An iterative procedure was developed to handle a boundary condition that takes into account the mandibular asymmetries. The results showed asymmetries in the contact pressure distributions that indicated with precision the patient's malocclusion diagnosis. In vivo measurements of contact pressure using piezoelectric sensors agreed with the computational results. It was shown that the left and right ends of the expansion screw move differently with respect to the patient mandible, even though the expansion screw has an opening mechanism to ensure equal stretching at both ends. The contact pressures between the apparatus and the mucosa vary linearly with applied forces, which can simplify the analysis of the biomechanical behaviour of the expander mandible apparatus. The biomechanical modelling proposed in this paper can be a useful tool to improve malocclusions treatment, safely avoiding the use of forces acting on live structures beyond the biological tolerance, which could result in traumatic effects.

  9. A leader-followers model of transmission augmentation for considering strategic behaviours of generating companies in energy markets

    International Nuclear Information System (INIS)

    Hesamzadeh, M.R.; Hosseinzadeh, N.; Wolfs, P.J.

    2010-01-01

    This paper suggests an integrated mathematical framework developed based on the leader-followers game for augmentation of transmission networks. Transmission Network Service Provider moves first and designs the horizon year transmission system. Generating Companies compete for having the highest share from the energy market and they find their equilibrium point using the Nash equilibrium concept. Finally, Market Management Company receives the planning schedule of transmission system and the energy offer prices and clears the market. In addition to the exact mathematical modelling of the interested players of transmission planning problem, the methodology can design the future transmission system not only for improving the system social welfare but also for encouraging competition among horizon year generating companies. (author)

  10. An integrated supply chain model for deteriorating items considering delay in payments, imperfect quality and inspection errors under inflationary conditions

    DEFF Research Database (Denmark)

    Mahmoudinezhad, Mahvash; Mirzazadeh, Abolfazl; Ghoreishi, Maryam

    2017-01-01

    In this article, an integrated production–distribution model is presented for a manufacturer and retailer supply chain under inflationary conditions, permissible delay in payments, deterioration, imperfect production process and inspection errors. We assume that the first-stage inspection...... of the manufacturer is not perfect and makes inspection errors of Type 1 and Type 2. The second-stage inspection of the manufacturer is at the end of production period without inspection errors. Also, the demand is linear function of time. Once the retailer receives the lot, a 100% screening process of the lot...... is conducted without inspection errors, and the screening process and demand proceed simultaneously. The main objective is to determine the optimal inspection time and the optimal number of cycle such that the present value of the total cost is minimized. Finally, a numerical example and sensitivity analyses...

  11. Temporal dynamics of interference in Simon and Eriksen tasks considered within the context of a dual-process model.

    Science.gov (United States)

    Mansfield, Karen L; van der Molen, Maurits W; Falkenstein, Michael; van Boxtel, Geert J M

    2013-08-01

    Behavioral and brain potential measures were employed to compare interference in Eriksen and Simon tasks. Assuming a dual-process model of interference elicited in speeded response tasks, we hypothesized that only lateralized stimuli in the Simon task induce fast S-R priming via direct unconditional processes, while Eriksen interference effects are induced later via indirect conditional processes. Delays to responses for incongruent trials were indeed larger in the Eriksen than in the Simon task. Only lateralized stimuli in the Simon task elicited early S-R priming, maximal at parietal areas. Incongruent flankers in the Eriksen task elicited interference later, visible as a lateralized N2. Eriksen interference also elicited an additional component (N350), which accounted for the larger behavioral interference effects in the Eriksen task. The findings suggest that interference and its resolution involve different processes for Simon and Eriksen tasks. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Conditioning factors of test-taking engagement in PIAAC: an exploratory IRT modelling approach considering person and item characteristics

    Directory of Open Access Journals (Sweden)

    Frank Goldhammer

    2017-11-01

    Full Text Available Abstract Background A potential problem of low-stakes large-scale assessments such as the Programme for the International Assessment of Adult Competencies (PIAAC is low test-taking engagement. The present study pursued two goals in order to better understand conditioning factors of test-taking disengagement: First, a model-based approach was used to investigate whether item indicators of disengagement constitute a continuous latent person variable by domain. Second, the effects of person and item characteristics were jointly tested using explanatory item response models. Methods Analyses were based on the Canadian sample of Round 1 of the PIAAC, with N = 26,683 participants completing test items in the domains of literacy, numeracy, and problem solving. Binary item disengagement indicators were created by means of item response time thresholds. Results The results showed that disengagement indicators define a latent dimension by domain. Disengagement increased with lower educational attainment, lower cognitive skills, and when the test language was not the participant’s native language. Gender did not exert any effect on disengagement, while age had a positive effect for problem solving only. An item’s location in the second of two assessment modules was positively related to disengagement, as was item difficulty. The latter effect was negatively moderated by cognitive skill, suggesting that poor test-takers are especially likely to disengage with more difficult items. Conclusions The negative effect of cognitive skill, the positive effect of item difficulty, and their negative interaction effect support the assumption that disengagement is the outcome of individual expectations about success (informed disengagement.

  13. An Optimization Model for Large–Scale Wind Power Grid Connection Considering Demand Response and Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Zhongfu Tan

    2014-11-01

    Full Text Available To reduce the influence of wind power output uncertainty on power system stability, demand response (DRPs and energy storage systems (ESSs are introduced while solving scheduling optimization problems. To simulate wind power scenarios, this paper uses Latin Hypercube Sampling (LHS to generate the initial scenario set and constructs a scenario reduction strategy based on Kantorovich distance. Since DRPs and ESSs can influence the distribution of demand load, this paper constructs a joint scheduling optimization model for wind power, ESSs and DRPs under the objective of minimizing total coal cost, and constraints of power demand and supply balance, users’ demand elasticity, thermal units’ startup-shutdown, thermal units’ output power climbing and wind power backup service. To analyze the influences of ESSs and DRPs on system wind power consumption capacity, example simulation is made in a 10 thermal units system with a 1000 MW wind farm and 400 MW energy storage systems under four simulation scenarios. The simulation results show that the introduction of DRPs and ESSs could promote system wind power consumption capacity with significantly economic and environment benefits, which include less coal consumption and less pollutant emission; and the optimization effect reaches the optimum when DRPs and ESSs are both introduced.

  14. 3D modeling and curvature analysis of orthogonal face gear considering the rounding tooth top of shaper cutter

    Science.gov (United States)

    Sun, Y. G.; Zhao, X. H.; Zhao, J.; Li, F. L.

    2017-09-01

    Aiming at the lack of the theory of transitional surface of face gear, the tooth profile equation of the orthogonal face gear is derived according to the differential geometry and meshing principle; In this paper, a tooth surface structure is proposed, which is a smooth surface of the tooth root transition part. A method of generating transition surface is presented, which takes into account the rounding tooth top of gear shaper cutter; the smooth transition surface equation of face gear tooth root is derived. The 3D solid model of the orthogonal face gear generated by two kinds of structures, the top angle of the gear shaper cutter and the addendum of the gear shaper cutter are established. The curvature analysis shows that the radius of curvature of the orthogonal face gear cut by the rounding tooth top of shaper cutter is larger than the other. The influence of the main parameters on the surface curvature of the face gear transmission is analyzed, the conclusion has reference value for the strength calculation and analysis of the face gear transmission.

  15. A dynamic programming approach for modeling low-carbon fuel technology adoption considering learning-by-doing effect

    International Nuclear Information System (INIS)

    Chen, Yuche; Zhang, Yunteng; Fan, Yueyue; Hu, Kejia; Zhao, Jianyou

    2017-01-01

    Highlights: • Dynamic programming method is used in transportation fuel portfolio planning. • The learning effect in new fuel technology is endogenously modeled through an experience curve. • Cellulosic biofuels play critical role in de-carbonization transport sector in near term. • The initial 3–4 billion gallons production is critical to bring down cellulosic biofuels’ cost. • Large penetration of Zero Emission Vehicles will discourage development of cellulosic biofuels. - Abstract: Promoting the adoption of low-carbon technologies in the transportation fuel portfolio is an effective strategy to mitigate greenhouse gas emissions from the transportation sector worldwide. However, as one of the most promising low-carbon fuels, cellulosic biofuel has not fully entered commercial production. Governments could provide guidance in developing cellulosic biofuel technologies, but no systematic approach has been proposed yet. We establish a dynamic programming framework for investigating time-dependent and adaptive decision-making processes to develop advanced fuel technologies. The learning-by-doing effect inherited in the technology development process is included in the framework. The proposed framework is applied in a case study to explore the most economical pathway for California to develop a solid cellulosic biofuel industry under its Low Carbon Fuel Standard. Our results show that cellulosic biofuel technology is playing a critical role in guaranteeing California’s 10% greenhouse gas emission reduction by 2020. Three to four billion gallons of cumulative production are needed to ensure that cellulosic biofuel is cost-competitive with petroleum-based fuels or conventional biofuels. Zero emission vehicle promoting policies will discourage the development of cellulosic biofuel. The proposed framework, with small adjustments, can also be applied to study new technology development in other energy sectors.

  16. Molecular and mathematical modeling analyses of inter-island transmission of rabies into a previously rabies-free island in the Philippines.

    Science.gov (United States)

    Tohma, Kentaro; Saito, Mariko; Demetria, Catalino S; Manalo, Daria L; Quiambao, Beatriz P; Kamigaki, Taro; Oshitani, Hitoshi

    2016-03-01

    Rabies is endemic in the Philippines and dog bites are a major cause of rabies cases in humans. The rabies control program has not been successful in eliminating rabies because of low vaccination coverage among dogs. Therefore, more effective and feasible strategies for rabies control are urgently required in the country. To control rabies, it is very important to know if inter-island transmission can occur because rabies can become endemic once the virus is introduced in areas that previously had no reported cases. Our molecular epidemiological study suggests that inter-island transmission events can occur; therefore, we further investigated these inter-island transmission using phylogenetic and modeling approaches. We investigate inter-island transmission between Luzon and Tablas Islands in the Philippines. Phylogenetic analysis and mathematical modeling demonstrate that there was a time lag of several months to a year from rabies introduction to initial case detection, indicating the difficulties in recognizing the initial rabies introductory event. There had been no rabies cases reported in Tablas Island; however, transmission chain was sustained on this island after the introduction of rabies virus because of low vaccination coverage among dogs. Across the islands, a rabies control program should include control of inter-island dog transportation and rabies vaccination to avoid viral introduction from the outside and to break transmission chains after viral introduction. However, this program has not yet been completely implemented and transmission chains following inter-island virus transmission are still observed. Local government units try to control dog transport; however, it should be more strictly controlled, and a continuous rabies control program should be implemented to prevent rabies spread even in rabies-free areas. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Modeling Operation Problem of Micro-grids Considering Economical, Technical and Environmental issues as Mixed-Integer Non-Linear Programming

    Directory of Open Access Journals (Sweden)

    Samira Salahi

    2016-08-01

    Full Text Available Reduction of fossil resources, increasing the production of greenhouse gas emissions and demand growth lead to greater use of distributed energy resources in power system especially in distribution networks. Integrating these resources in order to supply local loads creates a new concept called micro-grid. Optimal operation of micro-grid in the specific time period is one of the most important problems of them. In this paper, the operation problem of micro-grids is modeled considering the economical, technical and environmental issues, as well as uncertainties related to loads, wind speed and solar radiation. The resulting model is a Mixed-Integer Non-Linear Programming (MINLP. To demonstrate the effectiveness of the proposed model, Bisheh village in Iran is considered as a case study. The results showed that considering load curtailment costs, the power losses of the main grid, the penalties of pollutant gasses emissions and the elimination of energy subsides will tremendous impacts on the operation of microgrids. Article History: Received March 12, 2016; Received in revised form June 20, 2016; Accepted July 2nd 2016; Available online How to Cite This Article: Salahi, S., and Bahramara, S. (2016 Modeling Operation Problem of Micro-grids Considering Economical, Technical and Environmental issues as Mixed-Integer Non-Linear Programming. Int. Journal of Renewable Energy Development, 5(2, 139-149. http://dx.doi.org/10.14710/ijred.5.2.139-149 

  18. A New Hybrid Model FPA-SVM Considering Cointegration for Particular Matter Concentration Forecasting: A Case Study of Kunming and Yuxi, China

    Directory of Open Access Journals (Sweden)

    Weide Li

    2017-01-01

    Full Text Available Air pollution in China is becoming more serious especially for the particular matter (PM because of rapid economic growth and fast expansion of urbanization. To solve the growing environment problems, daily PM2.5 and PM10 concentration data form January 1, 2015, to August 23, 2016, in Kunming and Yuxi (two important cities in Yunnan Province, China are used to present a new hybrid model CI-FPA-SVM to forecast air PM2.5 and PM10 concentration in this paper. The proposed model involves two parts. Firstly, due to its deficiency to assess the possible correlation between different variables, the cointegration theory is introduced to get the input-output relationship and then obtain the nonlinear dynamical system with support vector machine (SVM, in which the parameters c and g are optimized by flower pollination algorithm (FPA. Six benchmark models, including FPA-SVM, CI-SVM, CI-GA-SVM, CI-PSO-SVM, CI-FPA-NN, and multiple linear regression model, are considered to verify the superiority of the proposed hybrid model. The empirical study results demonstrate that the proposed model CI-FPA-SVM is remarkably superior to all considered benchmark models for its high prediction accuracy, and the application of the model for forecasting can give effective monitoring and management of further air quality.

  19. A multi-objective model for closed-loop supply chain optimization and efficient supplier selection in a competitive environment considering quantity discount policy

    Science.gov (United States)

    Jahangoshai Rezaee, Mustafa; Yousefi, Samuel; Hayati, Jamileh

    2017-06-01

    Supplier selection and allocation of optimal order quantity are two of the most important processes in closed-loop supply chain (CLSC) and reverse logistic (RL). So that providing high quality raw material is considered as a basic requirement for a manufacturer to produce popular products, as well as achieve more market shares. On the other hand, considering the existence of competitive environment, suppliers have to offer customers incentives like discounts and enhance the quality of their products in a competition with other manufacturers. Therefore, in this study, a model is presented for CLSC optimization, efficient supplier selection, as well as orders allocation considering quantity discount policy. It is modeled using multi-objective programming based on the integrated simultaneous data envelopment analysis-Nash bargaining game. In this study, maximizing profit and efficiency and minimizing defective and functions of delivery delay rate are taken into accounts. Beside supplier selection, the suggested model selects refurbishing sites, as well as determining the number of products and parts in each network's sector. The suggested model's solution is carried out using global criteria method. Furthermore, based on related studies, a numerical example is examined to validate it.

  20. A Multiple Items EPQ/EOQ Model for a Vendor and Multiple Buyers System with Considering Continuous and Discrete Demand Simultaneously

    Science.gov (United States)

    Jonrinaldi; Rahman, T.; Henmaidi; Wirdianto, E.; Zhang, D. Z.

    2018-03-01

    This paper proposed a mathematical model for multiple items Economic Production and Order Quantity (EPQ/EOQ) with considering continuous and discrete demand simultaneously in a system consisting of a vendor and multiple buyers. This model is used to investigate the optimal production lot size of the vendor and the number of shipments policy of orders to multiple buyers. The model considers the multiple buyers’ holding cost as well as transportation cost, which minimize the total production and inventory costs of the system. The continuous demand from any other customers can be fulfilled anytime by the vendor while the discrete demand from multiple buyers can be fulfilled by the vendor using the multiple delivery policy with a number of shipments of items in the production cycle time. A mathematical model is developed to illustrate the system based on EPQ and EOQ model. Solution procedures are proposed to solve the model using a Mixed Integer Non Linear Programming (MINLP) and algorithm methods. Then, the numerical example is provided to illustrate the system and results are discussed.

  1. Medical resource inventory model for emergency preparation with uncertain demand and stochastic occurrence time under considering different risk preferences at the airport.

    Directory of Open Access Journals (Sweden)

    Wei Pan

    Full Text Available With the high accident rate of civil aviation, medical resource inventory becomes more important for emergency management at the airport. Meanwhile, medical products usually are time-sensitive and short lifetime. Moreover, we find that the optimal medical resource inventory depends on multiple factors such as different risk preferences, the material shelf life and so on. Thus, it becomes very complex in a real-life environment. According to this situation, we construct medical resource inventory decision model for emergency preparation at the airport. Our model is formulated in such a way as to simultaneously consider uncertain demand, stochastic occurrence time and different risk preferences. For solving this problem, a new programming is developed. Finally, a numerical example is presented to illustrate the proposed method. The results show that it is effective for determining the optimal medical resource inventory for emergency preparation with uncertain demand and stochastic occurrence time under considering different risk preferences at the airport.

  2. Fatigue Model for the Structural Integrity Evaluation Applied to a Wind Turbine Concrete Shaft, Considering Corrosion and Freeze and Thaw Degradation

    DEFF Research Database (Denmark)

    Saucedo-Mora, Luis; Thöns, Sebastian

    2017-01-01

    Fatigue is one of the principal damage mechanisms in a slender concrete structure under cyclic loads. And needs to be calculated locally through all the structure, considering the lading conditions and the particularities of concrete. The model presented here is capable to account for the fatigue...... damage in a probabilistic way, relating the annual loading conditions for each point and the degradation processes with a probability of failure. The methodology is as well capable to model the effect of a repair and control the structural integrity using the monitored data....

  3. A Two-Stage Algorithm for the Closed-Loop Location-Inventory Problem Model Considering Returns in E-Commerce

    Directory of Open Access Journals (Sweden)

    Yanhui Li

    2014-01-01

    Full Text Available Facility location and inventory control are critical and highly related problems in the design of logistics system for e-commerce. Meanwhile, the return ratio in Internet sales was significantly higher than in the traditional business. Focusing on the existing problem in e-commerce logistics system, we formulate a closed-loop location-inventory problem model considering returned merchandise to minimize the total cost which is produced in both forward and reverse logistics networks. To solve this nonlinear mixed programming model, an effective two-stage heuristic algorithm named LRCAC is designed by combining Lagrangian relaxation with ant colony algorithm (AC. Results of numerical examples show that LRCAC outperforms ant colony algorithm (AC on optimal solution and computing stability. The proposed model is able to help managers make the right decisions under e-commerce environment.

  4. Effects of Film Modeling on the Reduction of Anxiety-Related Behaviors in Individuals Varying in Level of Previous Experience in the Stress Situation.

    Science.gov (United States)

    Melamed, Barbara G.; And Others

    1978-01-01

    Evaluated influence of film preparation on children undergoing dental sessions with respect to peer modeling v demonstration of procedures and amount of information. Children exposed to peer-model videotaped presentations immediately preceding their restorative treatment exhibited fewer disruptive behaviors and less apprehension than those…

  5. Estimation of the Characterized Tsunami Source Model considering the Complicated Shape of Tsunami Source by Using the observed waveforms of GPS Buoys in the Nankai Trough

    Science.gov (United States)

    Seto, S.; Takahashi, T.

    2017-12-01

    In the 2011 Tohoku earthquake tsunami disaster, the delay of understanding damage situation increased the human damage. To solve this problem, it is important to search the severe damaged areas. The tsunami numerical modeling is useful to estimate damages and the accuracy of simulation depends on the tsunami source. Seto and Takahashi (2017) proposed a method to estimate the characterized tsunami source model by using the limited observed data of GPS buoys. The model consists of Large slip zone (LSZ), Super large slip zone (SLSZ) and background rupture zone (BZ) as the Cabinet Office, Government of Japan (below COGJ) reported after the Tohoku tsunami. At the beginning of this method, the rectangular fault model is assumed based on the seismic magnitude and hypocenter reported right after an earthquake. By using the fault model, tsunami propagation is simulated numerically, and the fault model is improved after comparing the computed data with the observed data repeatedly. In the comparison, correlation coefficient and regression coefficient are used as indexes. They are calculated with the observed and the computed tsunami wave profiles. This repetition is conducted to get the two coefficients close to 1.0, which makes the precise of the fault model higher. However, it was indicated as the improvement that the model did not examine a complicated shape of tsunami source. In this study, we proposed an improved model to examine the complicated shape. COGJ(2012) assumed that possible tsunami source region in the Nankai trough consisted of the several thousands small faults. And, we use these small faults to estimate the targeted tsunami source in this model. Therefore, we can estimate the complicated tsunami source by using these small faults. The estimation of BZ is carried out as a first step, and LSZ and SLSZ are estimated next as same as the previous model. The proposed model by using GPS buoy was applied for a tsunami scenario in the Nankai Trough. As a result

  6. Marine traffic model based on cellular automaton: Considering the change of the ship's velocity under the influence of the weather and sea

    Science.gov (United States)

    Qi, Le; Zheng, Zhongyi; Gang, Longhui

    2017-10-01

    It was found that the ships' velocity change, which is impacted by the weather and sea, e.g., wind, sea wave, sea current, tide, etc., is significant and must be considered in the marine traffic model. Therefore, a new marine traffic model based on cellular automaton (CA) was proposed in this paper. The characteristics of the ship's velocity change are taken into account in the model. First, the acceleration of a ship was divided into two components: regular component and random component. Second, the mathematical functions and statistical distribution parameters of the two components were confirmed by spectral analysis, curve fitting and auto-correlation analysis methods. Third, by combining the two components, the acceleration was regenerated in the update rules for ships' movement. To test the performance of the model, the ship traffic flows in the Dover Strait, the Changshan Channel and the Qiongzhou Strait were studied and simulated. The results show that the characteristics of ships' velocities in the simulations are consistent with the measured data by Automatic Identification System (AIS). Although the characteristics of the traffic flow in different areas are different, the velocities of ships can be simulated correctly. It proves that the velocities of ships under the influence of weather and sea can be simulated successfully using the proposed model.

  7. The study on the pH behavior of the HFSC leached solution. The development of model considering the pozzolanic reaction

    International Nuclear Information System (INIS)

    Yoshida, Yasushi; Mihara, Morihiro

    2005-09-01

    The development of low alkalinity cement (high fly-ash contained silica-fume cement, HFSC) has been carried out in JNC. Low alkalinity for this cement is achieved by adding pozzolan materials to ordinary portland cement and Ca ion attributed to high alkalinity is consumed by forming CHS gel. This report shows the calculation model to predict the composition for HFSC reacted solution which considers cement mineral dissolution/precipitation as equilibrium reactions and dissolution for pozzolan material as a kinetic reaction. The dissolution kinetic equation for pozzolan material is also derived from leaching experiment. This calculation model is applied to the leaching experiment where powdered HFSC was reacted with distilled water. As a result of comparison between calculation and experimental measurement at the early stage for leaching the tendency for pH, pH decrease from 12.5 to 11.5 drastically, could be interpreted by this calculation model, however, after this drastic pH decreasing pH predicted by calculation model also shows drastic decrease whereas pH for experiment decreased mildly around pH 11.5. It could be thought that this difference between experiment and calculation is caused by inappropriate modelling for CSH gel dissolution/precipitation of C/S value lower than 1.0. For this C/S range thermodynamic data for intermediate and end member for solid solution for CSH gel and in addition the reaction kinetic for CSH gel should be examined in detail. (author)

  8. Modelling of near-field radionuclide transport phenomena in a KBS-3V type of repository for nuclear waste with Goldsim Code - and verification against previous methods

    International Nuclear Information System (INIS)

    Pulkkanen, V.-M.; Nordman, H.

    2010-03-01

    Traditional radionuclide transport models overestimate significantly some phenomena, or completely ignore them. This motivates the development of new more precise models. As a result, this work is a description of commissioning of a new KBS-3V near-field radionuclide transport model, which has been done with a commercial software called GoldSim. According to earlier models, GoldSim model uses rz coordinates, but the solubilities of radionuclides have been treated more precisely. To begin with, the physical phenomena concerning near-field transport have been introduced according to GoldSim way of thinking. Also, the computational methods of GoldSim have been introduced and compared to methods used earlier. The actual verification of GoldSim model has been carried out by comparing the GoldSim results from simple cases to the corresponding results obtained with REPCOM, a software developed by VTT and used in several safety assessments. The results agree well. Finally, a few complicated cases were studied. In these cases, the REPCOM's limitations in handling of some phenomena become evident. The differences in the results are caused especially by the extension of the solubility limit to the whole computational domain, and the element-wise treatment of the solubilities which was used instead of nuclide-wise treatment. This work has been carried out as a special assignment to the former laboratory of Advanced Energy Systems in Helsinki University of Technology. The work was done at VTT. (orig.)

  9. Modelling of near-field radionuclide transport phenomena in a KBS-3V type of repository for nuclear waste with Goldsim Code - and verification against previous methods

    Energy Technology Data Exchange (ETDEWEB)

    Pulkkanen, V.-M.; Nordman, H. (VTT Technical Research Centre, Espoo (Finland))

    2010-03-15

    Traditional radionuclide transport models overestimate significantly some phenomena, or completely ignore them. This motivates the development of new more precise models. As a result, this work is a description of commissioning of a new KBS-3V near-field radionuclide transport model, which has been done with a commercial software called GoldSim. According to earlier models, GoldSim model uses rz coordinates, but the solubilities of radionuclides have been treated more precisely. To begin with, the physical phenomena concerning near-field transport have been introduced according to GoldSim way of thinking. Also, the computational methods of GoldSim have been introduced and compared to methods used earlier. The actual verification of GoldSim model has been carried out by comparing the GoldSim results from simple cases to the corresponding results obtained with REPCOM, a software developed by VTT and used in several safety assessments. The results agree well. Finally, a few complicated cases were studied. In these cases, the REPCOM's limitations in handling of some phenomena become evident. The differences in the results are caused especially by the extension of the solubility limit to the whole computational domain, and the element-wise treatment of the solubilities which was used instead of nuclide-wise treatment. This work has been carried out as a special assignment to the former laboratory of Advanced Energy Systems in Helsinki University of Technology. The work was done at VTT. (orig.)

  10. An integer batch scheduling model considering learning, forgetting, and deterioration effects for a single machine to minimize total inventory holding cost

    Science.gov (United States)

    Yusriski, R.; Sukoyo; Samadhi, T. M. A. A.; Halim, A. H.

    2018-03-01

    This research deals with a single machine batch scheduling model considering the influenced of learning, forgetting, and machine deterioration effects. The objective of the model is to minimize total inventory holding cost, and the decision variables are the number of batches (N), batch sizes (Q[i], i = 1, 2, .., N) and the sequence of processing the resulting batches. The parts to be processed are received at the right time and the right quantities, and all completed parts must be delivered at a common due date. We propose a heuristic procedure based on the Lagrange method to solve the problem. The effectiveness of the procedure is evaluated by comparing the resulting solution to the optimal solution obtained from the enumeration procedure using the integer composition technique and shows that the average effectiveness is 94%.

  11. Scintillation of partially coherent Gaussian—Schell model beam propagation in slant atmospheric turbulence considering inner- and outer-scale effects

    International Nuclear Information System (INIS)

    Li Ya-Qing; Wu Zhen-Sen; Zhang Yuan-Yuan; Wang Ming-Jun

    2014-01-01

    Based on the modified Rytov theory and the international telecommunication union-radio (ITU-R) slant atmospheric structure constant model, the uniform scintillation index of partially coherent Gaussian—Schell model (GSM) beam propagation in the slant path is derived from weak- to strong-turbulence regions considering inner- and outer-scale effects. The effects of wavelength of beams and inner- and outer-scale of turbulence on scintillation are analyzed numerically. Comparison between the scintillation of GSM beams under the von Karman spectrum and that of beams under the modified Hill spectrum is made. The results obtained show that the scintillation index obtained under the von Karman spectrum is smaller than that under the modified Hill spectrum. This study can find theory bases for the experiments of the partially coherent GSM beam propagation through atmospheric turbulence. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  12. Modeling driver stop/run behavior at the onset of a yellow indication considering driver run tendency and roadway surface conditions.

    Science.gov (United States)

    Elhenawy, Mohammed; Jahangiri, Arash; Rakha, Hesham A; El-Shawarby, Ihab

    2015-10-01

    The ability to model driver stop/run behavior at signalized intersections considering the roadway surface condition is critical in the design of advanced driver assistance systems. Such systems can reduce intersection crashes and fatalities by predicting driver stop/run behavior. The research presented in this paper uses data collected from two controlled field experiments on the Smart Road at the Virginia Tech Transportation Institute (VTTI) to model driver stop/run behavior at the onset of a yellow indication for different roadway surface conditions. The paper offers two contributions. First, it introduces a new predictor related to driver aggressiveness and demonstrates that this measure enhances the modeling of driver stop/run behavior. Second, it applies well-known artificial intelligence techniques including: adaptive boosting (AdaBoost), random forest, and support vector machine (SVM) algorithms as well as traditional logistic regression techniques on the data in order to develop a model that can be used by traffic signal controllers to predict driver stop/run decisions in a connected vehicle environment. The research demonstrates that by adding the proposed driver aggressiveness predictor to the model, there is a statistically significant increase in the model accuracy. Moreover the false alarm rate is significantly reduced but this reduction is not statistically significant. The study demonstrates that, for the subject data, the SVM machine learning algorithm performs the best in terms of optimum classification accuracy and false positive rates. However, the SVM model produces the best performance in terms of the classification accuracy only. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Optimizing the safety margins governing a deterministic design process while considering the effects of a future test and redesign on epistemic model uncertainty

    Science.gov (United States)

    Price, Nathaniel B.

    At the initial design stage, engineers often rely on low-fidelity models that have high uncertainty. Model uncertainty is reducible and is classified as epistemic uncertainty; uncertainty due to variability is irreducible and classified as aleatory uncertainty. In a deterministic safety-margin-based design approach, uncertainty is implicitly compensated for by using fixed conservative values in place of aleatory variables and ensuring the design satisfies a safety-margin with respect to design constraints. After an initial design is selected, testing (e.g. physical experiment or high-fidelity simulation) is performed to reduce epistemic uncertainty and ensure the design achieves the targeted levels of safety. Testing is used to calibrate low-fidelity models and prescribe redesign when tests are not passed. After calibration, reduced epistemic model uncertainty can be leveraged through redesign to restore safety or improve design performance; however, redesign may be associated with substantial costs or delays. In this work, the possible effects of a future test and redesign are considered while the initial design is optimized using only a low-fidelity model. The goal is to develop a general method for the integrated optimization of the design, testing, and redesign process that allows for the tradeoff between the risk of future redesign and the associated performance and reliability benefits. This is accomplished by formulating the design, testing, and redesign process in terms of safety-margins and optimizing these margins based on expected performance, expected probability of failure, and probability of redesign. The first objective of this study is to determine how the degree of conservativeness in the initial design relates to the expected design performance after a test and possible redesign. The second objective is to develop a general method for modeling epistemic model uncertainty and calibration when simulating a possible future test and redesign. The

  14. Joint DEnKF-albedo assimilation scheme that considers the common land model subgrid heterogeneity and a snow density-based observation operator for improving snow depth simulations

    Science.gov (United States)

    Xu, Jianhui; Zhang, Feifei; Zhao, Yi; Shu, Hong; Zhong, Kaiwen

    2016-07-01

    For the large-area snow depth (SD) data sets with high spatial resolution in the Altay region of Northern Xinjiang, China, we present a deterministic ensemble Kalman filter (DEnKF)-albedo assimilation scheme that considers the common land model (CoLM) subgrid heterogeneity. In the albedo assimilation of DEnKF-albedo, the assimilated albedos over each subgrid tile are estimated with the MCD43C1 bidirectional reflectance distribution function (BRDF) parameters product and CoLM calculated solar zenith angle. The BRDF parameters are hypothesized to be consistent over all subgrid tiles within a specified grid. In the SCF assimilation of DEnKF-albedo, a DEnKF combining a snow density-based observation operator considers the effects of the CoLM subgrid heterogeneity and is employed to assimilate MODIS SCF to update SD states over all subgrid tiles. The MODIS SCF over a grid is compared with the area-weighted sum of model predicted SCF over all the subgrid tiles within the grid. The results are validated with in situ SD measurements and AMSR-E product. Compared with the simulations, the DEnKF-albedo scheme can reduce errors of SD simulations and accurately simulate the seasonal variability of SD. Furthermore, it can improve simulations of SD spatiotemporal distribution in the Altay region, which is more accurate and shows more detail than the AMSR-E product.

  15. A fuzzy-stochastic simulation-optimization model for planning electric power systems with considering peak-electricity demand: A case study of Qingdao, China

    International Nuclear Information System (INIS)

    Yu, L.; Li, Y.P.; Huang, G.H.

    2016-01-01

    In this study, a FSSOM (fuzzy-stochastic simulation-optimization model) is developed for planning EPS (electric power systems) with considering peak demand under uncertainty. FSSOM integrates techniques of SVR (support vector regression), Monte Carlo simulation, and FICMP (fractile interval chance-constrained mixed-integer programming). In FSSOM, uncertainties expressed as fuzzy boundary intervals and random variables can be effectively tackled. In addition, SVR coupled Monte Carlo technique is used for predicting the peak-electricity demand. The FSSOM is applied to planning EPS for the City of Qingdao, China. Solutions of electricity generation pattern to satisfy the city's peak demand under different probability levels and p-necessity levels have been generated. Results reveal that the city's electricity supply from renewable energies would be low (only occupying 8.3% of the total electricity generation). Compared with the energy model without considering peak demand, the FSSOM can better guarantee the city's power supply and thus reduce the system failure risk. The findings can help decision makers not only adjust the existing electricity generation/supply pattern but also coordinate the conflict interaction among system cost, energy supply security, pollutant mitigation, as well as constraint-violation risk. - Highlights: • FSSOM (Fuzzy-stochastic simulation-optimization model) is developed for planning EPS. • It can address uncertainties as fuzzy-boundary intervals and random variables. • FSSOM can satisfy peak-electricity demand and optimize power allocation. • Solutions under different probability levels and p-necessity levels are analyzed. • Results create tradeoff among system cost and peak-electricity demand violation risk.

  16. Modeling of conductive particle motion in viscous medium affected by an electric field considering particle-electrode interactions and microdischarge phenomenon

    Science.gov (United States)

    Eslami, Ghiyam; Esmaeilzadeh, Esmaeil; Pérez, Alberto T.

    2016-10-01

    Up and down motion of a spherical conductive particle in dielectric viscous fluid driven by a DC electric field between two parallel electrodes was investigated. A nonlinear differential equation, governing the particle dynamics, was derived, based on Newton's second law of mechanics, and solved numerically. All the pertaining dimensionless groups were extracted. In contrast to similar previous works, hydrodynamic interaction between the particle and the electrodes, as well as image electric forces, has been taken into account. Furthermore, the influence of the microdischarge produced between the electrodes and the approaching particle on the particle dynamics has been included in the model. The model results were compared with experimental data available in the literature, as well as with some additional experimental data obtained through the present study showing very good agreement. The results indicate that the wall hydrodynamic effect and the dielectric liquid ionic conductivity are very dominant factors determining the particle trajectory. A lower bound is derived for the charge transferred to the particle while rebounding from an electrode. It is found that the time and length scales of the post-microdischarge motion of the particle can be as small as microsecond and micrometer, respectively. The model is able to predict the so called settling/dwelling time phenomenon for the first time.

  17. Rituximab, Cyclophosphamide, Dexamethasone (RCD) regimen induces cure in WSU-WM xenograft model and a partial remission in previously treated Waldenstrom's macroglobulinemia patient.

    Science.gov (United States)

    Mohammad, Ramzi M; Aboukameel, Amro; Nabha, Sanaa; Ibrahim, Dina; Al-Katib, Ayad

    2002-08-01

    Waldenstrom's macroglobulinemia (WM) is an uncommon lymphoproliferative disease which remains incurable with current treatment protocols. We have previously established a permanent WM cell line, WSU-WM, which grows as a xenograft in severe combined immune deficient (SCID) mice. In this study, we investigated the antitumor effects of Rituximab (RTX), Cyclophosphamide (CTX), Dexamethasone (DEX) [RCD]-Regimen in vivo WSU-WM SCID xenograft and in a patient with WM. For the pre-clinical efficacy study, WSU-WM-bearing SCID mice were randomly assigned to receive RTX (150 mg/kg/inj, i.v., QDX5), CTX (90 mg/kg/inj, s.c. QDX5) as single agents or diluent. The combination group received RTX at 150 mg/kg/inj, QDX5; CTX at 150 mg/kg/inj, QODX3 and DEX at 1.0 mg/kg/inj, i.v., QDX5. Tumor growth inhibition (T/C), tumor growth delay (T - C), and log10 kill (net) for RTX and CTX were 24.5%, 37 days, 5.52 and 88%, 0.0 days, 0.0log10 kill, respectively. No cures were observed with either agent; however, all mice (6/6, with bilateral tumors) were cured when treated with RCD-regimen. A 57-year-old patient with relapsed WM was treated with the RCD-regimen and showed an excellent partial remission for seven months. The patient tolerated the treatment very well, the hemoglobin improved dramatically, platelets remained stable, the IgM level normalized and there was only minimal involvement of bone marrow. Based on these results, the RCD regimen is effective against WM and its activity should be further evaluated in clinical trials.

  18. The optimization model for multi-type customers assisting wind power consumptive considering uncertainty and demand response based on robust stochastic theory

    International Nuclear Information System (INIS)

    Tan, Zhongfu; Ju, Liwei; Reed, Brent; Rao, Rao; Peng, Daoxin; Li, Huanhuan; Pan, Ge

    2015-01-01

    Highlights: • Our research focuses on demand response behaviors of multi-type customers. • A wind power simulation method is proposed based on the Brownian motion theory. • Demand response revenue functions are proposed for multi-type customers. • A robust stochastic optimization model is proposed for wind power consumptive. • Models are built to measure the impacts of demand response on wind power consumptive. - Abstract: In order to relieve the influence of wind power uncertainty on power system operation, demand response and robust stochastic theory are introduced to build a stochastic scheduling optimization model. Firstly, this paper presents a simulation method for wind power considering external environment based on Brownian motion theory. Secondly, price-based demand response and incentive-based demand response are introduced to build demand response model. Thirdly, the paper constructs the demand response revenue functions for electric vehicle customers, business customers, industry customers and residential customers. Furthermore, robust stochastic optimization theory is introduced to build a wind power consumption stochastic optimization model. Finally, simulation analysis is taken in the IEEE 36 nodes 10 units system connected with 650 MW wind farms. The results show the robust stochastic optimization theory is better to overcome wind power uncertainty. Demand response can improve system wind power consumption capability. Besides, price-based demand response could transform customers’ load demand distribution, but its load curtailment capacity is not as obvious as incentive-based demand response. Since price-based demand response cannot transfer customer’s load demand as the same as incentive-based demand response, the comprehensive optimization effect will reach best when incentive-based demand response and price-based demand response are both introduced.

  19. Comment on "Assessing Discrepancies Between Previous Plate Kinematic Models of Mesozoic Iberia and Their Constraints" by Barnett-Moore Et Al.

    Science.gov (United States)

    van Hinsbergen, Douwe J. J.; Spakman, Wim; Vissers, Reinoud L. M.; van der Meer, Douwe G.

    2017-12-01

    In their recent paper, Barnett-Moore et al. (2016) reflect on current models of Iberian plate motion in the Jurassic and Cretaceous as well as ongoing debates on the reliability of the various types of kinematic data that form independent constraints on Iberia's motion relative to Eurasia. They question the validity of various marine geophysical, seismic, tomographic, geological, and paleomagnetic data sets from the Bay of Biscay, Central Atlantic Ocean, and Iberia for kinematic reconstruction of Iberia and conclude that neither models invoking Aptian-Albian transtension, nor compression, are consistent with currently available data. An important element in their analysis is that they discard the large paleomagnetic data set from the Jurassic and Cretaceous from Iberia based on perceived limitations of that data set. In addition, they argue that seismic tomographic images exclude a scenario of subduction in the Aptian-Albian in the Pyrenees, and based on this "question the validity of current plate reconstructions, their constraints, and geodynamic scenarios, which are in support of this scenario [e.g., Vissers et al., 2016]." We welcome the discussion raised by Barnett-Moore et al. (2016) on the reliability and usefulness of paleomagnetic data as independent constraint for Iberia's plate motion in the Mesozoic. Taking these paleomagnetic data at face value, Vissers et al. (2016) recently showed that these are consistent with an 40° counterclockwise rotation of Iberia in the Aptian, requiring up to 500 km of Aptian convergence across the Pyrenees, that is, through subduction. In this comment, we aim to critically assess whether and how the concerns on the quality of paleomagnetic data raised by Barnett-Moore et al. (2016) may allow for an alternative explanation, particularly one with a Mesozoic rotation of Iberia that is small enough so as to not requiring subduction. We also reassess whether seismic tomographic images indeed refute subduction scenarios, using 8

  20. Kirchhoff plate theory-based electromechanically-coupled analytical model considering inertia and stiffness effects of a surface-bonded piezoelectric patch

    International Nuclear Information System (INIS)

    Yoon, Heonjun; Youn, Byeng D; Kim, Heung Soo

    2016-01-01

    As a compact and durable design concept, piezoelectric energy harvesting skin (PEH skin) has been recently proposed for self-powered electronic device applications. This study aims to develop an electromechanically-coupled analytical model of PEH skin considering the inertia and stiffness effects of a piezoelectric patch. Based on Kirchhoff plate theory, Hamilton’s principle is used to derive the electromechanically-coupled differential equation of motion. Due to the geometric discontinuity of the piezoelectric patch, the Rayleigh–Ritz method is applied to calculate the natural frequency and corresponding mode shapes. The electrical circuit equation is derived from Gauss’s law. Output voltage is estimated by solving the equation of motion and electrical circuit equation, simultaneously. For the purpose of evaluating the predictive capability, the results of the electromechanically-coupled analytical model are compared with those of the finite element method in a hierarchical manner. The outstanding merits of the electromechanically-coupled analytical model of PEH skin are three-fold: (1) consideration of the inertia and stiffness effects of the piezoelectric patches; (2) physical parameterization between the two-dimensional mechanical configuration and piezoelectric transduction; (3) manipulability of the twisting modes of a cantilever plate with a small aspect ratio. (paper)

  1. A bi-level stochastic scheduling optimization model for a virtual power plant connected to a wind–photovoltaic–energy storage system considering the uncertainty and demand response

    International Nuclear Information System (INIS)

    Ju, Liwei; Tan, Zhongfu; Yuan, Jinyun; Tan, Qingkun; Li, Huanhuan; Dong, Fugui

    2016-01-01

    Highlights: • Our research focuses on Virtual Power Plant (VPP). • Virtual Power Plant consists of WPP, PV, CGT, ESSs and DRPs. • Robust optimization theory is introduced to analyze uncertainties. • A bi-level stochastic scheduling optimization model is proposed for VPP. • Models are built to measure the impacts of ESSs and DERPs on VPP operation. - Abstract: To reduce the uncertain influence of wind power and solar photovoltaic power on virtual power plant (VPP) operation, robust optimization theory (ROT) is introduced to build a stochastic scheduling model for VPP considering the uncertainty, price-based demand response (PBDR) and incentive-based demand response (IBDR). First, the VPP components are described including the wind power plant (WPP), photovoltaic generators (PV), convention gas turbine (CGT), energy storage systems (ESSs) and demand resource providers (DRPs). Then, a scenario generation and reduction frame is proposed for analyzing and simulating output stochastics based on the interval method and the Kantorovich distance. Second, a bi-level robust scheduling model is proposed with a double robust coefficient for WPP and PV. In the upper layer model, the maximum VPP operation income is taken as the optimization objective for building the scheduling model with the day-ahead prediction output of WPP and PV. In the lower layer model, the day-ahead scheduling scheme is revised with the actual output of the WPP and PV under the objectives of the minimum system net load and the minimum system operation cost. Finally, the independent micro-grid in a coastal island in eastern China is used for the simulation analysis. The results illustrate that the model can overcome the influence of uncertainty on VPP operations and reduce the system power shortage cost by connecting the day-ahead scheduling with the real-time scheduling. ROT could provide a flexible decision tool for decision makers, effectively addressing system uncertainties. ESSs could

  2. Global history of the ancient monocot family Araceae inferred with models accounting for past continental positions and previous ranges based on fossils.

    Science.gov (United States)

    Nauheimer, Lars; Metzler, Dirk; Renner, Susanne S

    2012-09-01

    The family Araceae (3790 species, 117 genera) has one of the oldest fossil records among angiosperms. Ecologically, members of this family range from free-floating aquatics (Pistia and Lemna) to tropical epiphytes. Here, we infer some of the macroevolutionary processes that have led to the worldwide range of this family and test how the inclusion of fossil (formerly occupied) geographical ranges affects biogeographical reconstructions. Using a complete genus-level phylogeny from plastid sequences and outgroups representing the 13 other Alismatales families, we estimate divergence times by applying different clock models and reconstruct range shifts under different models of past continental connectivity, with or without the incorporation of fossil locations. Araceae began to diversify in the Early Cretaceous (when the breakup of Pangea was in its final stages), and all eight subfamilies existed before the K/T boundary. Early lineages persist in Laurasia, with several relatively recent entries into Africa, South America, South-East Asia and Australia. Water-associated habitats appear to be ancestral in the family, and DNA substitution rates are especially high in free-floating Araceae. Past distributions inferred when fossils are included differ in nontrivial ways from those without fossils. Our complete genus-level time-scale for the Araceae may prove to be useful for ecological and physiological studies. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  3. Modeling and Solving the Multi-depot Vehicle Routing Problem with Time Window by Considering the Flexible end Depot in Each Route

    Directory of Open Access Journals (Sweden)

    Mohammad Mirabi

    2016-11-01

    Full Text Available This paper considers the multi-depot vehicle routing problem with time window in which each vehicle starts from a depot and there is no need to return to its primary depot after serving customers. The mathematical model which is developed by new approach aims to minimizing the transportation cost including the travelled distance, the latest and the earliest arrival time penalties. Furthermore, in order to reduce the problem searching space, a novel GA clustering method is developed. Finally, Experiments are run on number problems of varying depots and time window, and customer sizes. The method is compared to two other clustering techniques, fuzzy C means (FCM and K-means algorithm. Experimental results show the robustness and effectiveness of the proposed algorithm.

  4. Multi-objective stochastic scheduling optimization model for connecting a virtual power plant to wind-photovoltaic-electric vehicles considering uncertainties and demand response

    International Nuclear Information System (INIS)

    Ju, Liwei; Li, Huanhuan; Zhao, Junwei; Chen, Kangting; Tan, Qingkun; Tan, Zhongfu

    2016-01-01

    Highlights: • Our research focuses on virtual power plant. • Electric vehicle group and demand response are integrated into virtual power plant. • Stochastic chance constraint planning is applied to overcome uncertainties. • A multi-objective stochastic scheduling model is proposed for virtual power plant. • A three-stage hybrid intelligent solution algorithm is proposed for solving the model. - Abstract: A stochastic chance-constrained planning method is applied to build a multi-objective optimization model for virtual power plant scheduling. Firstly, the implementation cost of demand response is calculated using the system income difference. Secondly, a wind power plant, photovoltaic power, an electric vehicle group and a conventional power plant are aggregated into a virtual power plant. A stochastic scheduling model is proposed for the virtual power plant, considering uncertainties under three objective functions. Thirdly, a three-stage hybrid intelligent solution algorithm is proposed, featuring the particle swarm optimization algorithm, the entropy weight method and the fuzzy satisfaction theory. Finally, the Yunnan distributed power demonstration project in China is utilized for example analysis. Simulation results demonstrate that when considering uncertainties, the system will reduce the grid connection of the wind power plant and photovoltaic power to decrease the power shortage punishment cost. The average reduction of the system power shortage punishment cost and the operation revenue of virtual power plant are 61.5% and 1.76%, respectively, while the average increase of the system abandoned energy cost is 40.4%. The output of the virtual power plant exhibits a reverse distribution with the confidence degree of the uncertainty variable. The proposed algorithm rapidly calculates a global optimal set. The electric vehicle group could provide spinning reserve to ensure stability of the output of the virtual power plant. Demand response could

  5. Identification of a Patient Population Previously Not Considered for Organ Donation.

    Science.gov (United States)

    Barrois, Brad

    2016-09-26

    For the foreseeable future, more individuals will need a kidney than there are kidneys available for transplant. This is not a new issue, and it is one that will not likely be solved anytime soon. While recent initiatives have focused on efficiently allocating kidneys in order to maximize supply, a shortage will remain.  Currently, organs are made available for transplant through three different processes: donation after brain death declaration (BD), donation after circulatory death (DCD), and living donation (one healthy individual donates to a person in need). The objective of this article is to discuss the possibility of a fourth option in imminent death single kidney donation (IDSKD) and its potential effects on the future of donation and transplantation. During our study, IDSKD had the potential to increase the number of kidneys transplanted in our service area by approximately 5%.

  6. Considering Student Coaching

    Science.gov (United States)

    Keen, James P.

    2014-01-01

    What does student coaching involve and what considerations make sense in deciding to engage an outside contractor to provide personal coaching? The author explores coaching in light of his own professional experience and uses this reflection as a platform from which to consider the pros and cons of student coaching when deciding whether to choose…

  7. Why Not Consider Erdkinder?

    Science.gov (United States)

    Gebhardt-Seele, Peter

    1996-01-01

    Claims that Montessori's educational theory for 12- to 18- year olds, Erdkinder, should be considered as an educational alternative. Erdkinder, or "earth child," refers to observing children and, accordingly, creating a suitable environment. The task for education at this age is the creation of the socially conscious individual. Claims…

  8. Estimating the mean and standard deviation of environmental data with below detection limit observations: Considering highly skewed data and model misspecification.

    Science.gov (United States)

    Shoari, Niloofar; Dubé, Jean-Sébastien; Chenouri, Shoja'eddin

    2015-11-01

    In environmental studies, concentration measurements frequently fall below detection limits of measuring instruments, resulting in left-censored data. Some studies employ parametric methods such as the maximum likelihood estimator (MLE), robust regression on order statistic (rROS), and gamma regression on order statistic (GROS), while others suggest a non-parametric approach, the Kaplan-Meier method (KM). Using examples of real data from a soil characterization study in Montreal, we highlight the need for additional investigations that aim at unifying the existing literature. A number of studies have examined this issue; however, those considering data skewness and model misspecification are rare. These aspects are investigated in this paper through simulations. Among other findings, results show that for low skewed data, the performance of different statistical methods is comparable, regardless of the censoring percentage and sample size. For highly skewed data, the performance of the MLE method under lognormal and Weibull distributions is questionable; particularly, when the sample size is small or censoring percentage is high. In such conditions, MLE under gamma distribution, rROS, GROS, and KM are less sensitive to skewness. Related to model misspecification, MLE based on lognormal and Weibull distributions provides poor estimates when the true distribution of data is misspecified. However, the methods of rROS, GROS, and MLE under gamma distribution are generally robust to model misspecifications regardless of skewness, sample size, and censoring percentage. Since the characteristics of environmental data (e.g., type of distribution and skewness) are unknown a priori, we suggest using MLE based on gamma distribution, rROS and GROS. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Equivalent Circuit Model of Low-Frequency Magnetoelectric Effect in Disk-Type Terfenol-D/PZT Laminate Composites Considering a New Interface Coupling Factor

    Directory of Open Access Journals (Sweden)

    Guofeng Lou

    2017-06-01

    Full Text Available This paper describes the modeling of magnetoelectric (ME effects for disk-type Terfenol-D (Tb0.3Dy0.7Fe1.92/PZT (Pb(Zr,TiO3 laminate composite at low frequency by combining the advantages of the static elastic model and the equivalent circuit model, aiming at providing a guidance for the design and fabrication of the sensors based on magnetoelectric laminate composite. Considering that the strains of the magnetostrictive and piezoelectric layers are not equal in actual operating due to the epoxy resin adhesive bonding condition, the magnetostrictive and piezoelectric layers were first modeled through the equation of motion separately, and then coupled together with a new interface coupling factor kc, which physically reflects the strain transfer between the phases. Furthermore, a theoretical expression containing kc for the transverse ME voltage coefficient αv and the optimum thickness ratio noptim to which the maximum ME voltage coefficient corresponds were derived from the modified equivalent circuit of ME laminate, where the interface coupling factor acted as an ideal transformer. To explore the influence of mechanical load on the interface coupling factor kc, two sets of weights, i.e., 100 g and 500 g, were placed on the top of the ME laminates with the same thickness ratio n in the sample fabrication. A total of 22 T-T mode disk-type ME laminate samples with different configurations were fabricated. The interface coupling factors determined from the measured αv and the DC bias magnetic field Hbias were 0.11 for 500 g pre-mechanical load and 0.08 for 100 g pre-mechanical load. Furthermore, the measured optimum thickness ratios were 0.61 for kc = 0.11 and 0.56 for kc = 0.08. Both the theoretical ME voltage coefficient αv and optimum thickness ratio noptim containing kc agreed well with the measured data, verifying the reasonability and correctness for the introduction of kc in the modified equivalent circuit model.

  10. A review of dosimetry used in epidemiological studies considered to evaluate the linear no-threshold (LNT) dose-response model for radiation protection.

    Science.gov (United States)

    Till, John E; Beck, Harold L; Grogan, Helen A; Caffrey, Emily A

    2017-10-01

    Accurate dosimetry is key to deriving the dose response from radiation exposure in an epidemiological study. It becomes increasingly important to estimate dose as accurately as possible when evaluating low dose and low dose rate as the calculation of excess relative risk per Gray (ERR/Gy) is very sensitive to the number of excess cancers observed, and this can lead to significant errors if the dosimetry is of poor quality. By including an analysis of the dosimetry, we gain a far better appreciation of the robustness of the work from the standpoint of its value in supporting the shape of the dose response curve at low doses and low dose rates. This article summarizes a review of dosimetry supporting epidemiological studies currently being considered for a re-evaluation of the linear no-threshold assumption as a basis for radiation protection. The dosimetry for each study was evaluated based on important attributes from a dosimetry perspective. Our dosimetry review consisted of dosimetry supporting epidemiological studies published in the literature during the past 15 years. Based on our review, it is clear there is wide variation in the quality of the dosimetry underlying each study. Every study has strengths and weaknesses. The article describes the results of our review, explaining which studies clearly stand out for their strengths as well as common weaknesses among all investigations. To summarize a review of dosimetry used in epidemiological studies being considered by the National Council on Radiation Protection and Measurements (NCRP) in an evaluation of the linear no-threshold dose-response model that underpins the current framework of radiation protection. The authors evaluated each study using criteria considered important from a dosimetry perspective. The dosimetry analysis was divided into the following categories: (1) general study characteristics, (2) dose assignment, (3) uncertainty, (4) dose confounders (5) dose validation, and (6) strengths and

  11. Preoperative screening: value of previous tests.

    Science.gov (United States)

    Macpherson, D S; Snow, R; Lofgren, R P

    1990-12-15

    To determine the frequency of tests done in the year before elective surgery that might substitute for preoperative screening tests and to determine the frequency of test results that change from a normal value to a value likely to alter perioperative management. Retrospective cohort analysis of computerized laboratory data (complete blood count, sodium, potassium, and creatinine levels, prothrombin time, and partial thromboplastin time). Urban tertiary care Veterans Affairs Hospital. Consecutive sample of 1109 patients who had elective surgery in 1988. At admission, 7549 preoperative tests were done, 47% of which duplicated tests performed in the previous year. Of 3096 previous results that were normal as defined by hospital reference range and done closest to the time of but before admission (median interval, 2 months), 13 (0.4%; 95% CI, 0.2% to 0.7%), repeat values were outside a range considered acceptable for surgery. Most of the abnormalities were predictable from the patient's history, and most were not noted in the medical record. Of 461 previous tests that were abnormal, 78 (17%; CI, 13% to 20%) repeat values at admission were outside a range considered acceptable for surgery (P less than 0.001, frequency of clinically important abnormalities of patients with normal previous results with those with abnormal previous results). Physicians evaluating patients preoperatively could safely substitute the previous test results analyzed in this study for preoperative screening tests if the previous tests are normal and no obvious indication for retesting is present.

  12. System Reliability Analysis Considering Correlation of Performances

    International Nuclear Information System (INIS)

    Kim, Saekyeol; Lee, Tae Hee; Lim, Woochul

    2017-01-01

    Reliability analysis of a mechanical system has been developed in order to consider the uncertainties in the product design that may occur from the tolerance of design variables, uncertainties of noise, environmental factors, and material properties. In most of the previous studies, the reliability was calculated independently for each performance of the system. However, the conventional methods cannot consider the correlation between the performances of the system that may lead to a difference between the reliability of the entire system and the reliability of the individual performance. In this paper, the joint probability density function (PDF) of the performances is modeled using a copula which takes into account the correlation between performances of the system. The system reliability is proposed as the integral of joint PDF of performances and is compared with the individual reliability of each performance by mathematical examples and two-bar truss example.

  13. Estimation of interplate coupling along Nankai trough considering the block motion model based on onland GNSS and seafloor GPS/A observation data using MCMC method

    Science.gov (United States)

    Kimura, H.; Ito, T.; Tadokoro, K.

    2017-12-01

    Introduction In southwest Japan, Philippine sea plate is subducting under the overriding plate such as Amurian plate, and mega interplate earthquakes has occurred at about 100 years interval. There is no occurrence of mega interplate earthquakes in southwest Japan, although it has passed about 70 years since the last mega interplate earthquakes: 1944 and 1946 along Nankai trough, meaning that the strain has been accumulated at plate interface. Therefore, it is essential to reveal the interplate coupling more precisely for predicting or understanding the mechanism of next occurring mega interplate earthquake. Recently, seafloor geodetic observation revealed the detailed interplate coupling distribution in expected source region of Nankai trough earthquake (e.g., Yokota et al. [2016]). In this study, we estimated interplate coupling in southwest Japan, considering block motion model and using seafloor geodetic observation data as well as onland GNSS observation data, based on Markov Chain Monte Carlo (MCMC) method. Method Observed crustal deformation is assumed that sum of rigid block motion and elastic deformation due to coupling at block boundaries. We modeled this relationship as a non-linear inverse problem that the unknown parameters are Euler pole of each block and coupling at each subfault, and solved them simultaneously based on MCMC method. Input data we used in this study are 863 onland GNSS observation data and 24 seafloor GPS/A observation data. We made some block division models based on the map of active fault tracing and selected the best model based on Akaike's Information Criterion (AIC): that is consist of 12 blocks. Result We find that the interplate coupling along Nankai trough has heterogeneous spatial distribution, strong at the depth of 0 to 20km at off Tokai region, and 0 to 30km at off Shikoku region. Moreover, we find that observed crustal deformation at off Tokai region is well explained by elastic deformation due to subducting Izu Micro

  14. Modelo de un muelle de ballestas considerando la fricción entre hojas. // Laminated spring model considering the friction between leaves.

    Directory of Open Access Journals (Sweden)

    J. Rodríguez Matienzo

    2006-01-01

    Full Text Available Se brinda un modelo de una ballesta por el MEF incluyendo el contacto y la fricción. El problema se convierte en no linealy se resuelve por el método de Newton-Raphson como un problema de optimización con restricciones. Se hace un análisisde las condiciones iniciales y de contorno para alcanzar la solución en un tiempo razonable, dando una estrategia paracalcular el valor del penalty. Se logra una buena correspondencia en tre los valores de desplazamiento reales y teóricos.Finalmente se hace el análisis modal del modelo.Palabras claves: Ballestas, contacto, vibraciones, MEF._____________________________________________________________________________Abstract:A finite element model of a real laminated spring under bending should include the phenomena of contact and frictionbetween leaves, in order to obtain values of displacements, stresses, gap, etc. close to reality. Considering contact and friction leadsto a non-linear problem, which must be solved using numerical methods (Newton-Raphson, resulting in a classic optimizationproblem with constraints. The success of solution depends strongly on boundary conditions and initial values. A strategy fordetermining penalty values in the case of a multi leaf bending problem is presented, allowing a good correspondence with realdisplacements. The non-linear behavior of the leaf spring suspension referred to spring rate is shown. The modal analysis also gavefirsts natural frequencies in the usual span for trucks and semi-trailers.Key words: Laminated spring, contact, vibration.

  15. Conceptual aspects: analyses law, ethical, human, technical, social factors of development ICT, e-learning and intercultural development in different countries setting out the previous new theoretical model and preliminary findings

    NARCIS (Netherlands)

    Kommers, Petrus A.M.; Smyrnova-Trybulska, Eugenia; Morze, Natalia; Issa, Tomayess; Issa, Theodora

    2015-01-01

    This paper, prepared by an international team of authors focuses on the conceptual aspects: analyses law, ethical, human, technical, social factors of ICT development, e-learning and intercultural development in different countries, setting out the previous and new theoretical model and preliminary

  16. MODELOS DE SISTEMAS MRP CERRADOS INTEGRANDO INCERTIDUMBRE MODELOS DE SISTEMAS MRP FECHADOS INTEGRANDO INCERTEZA CLOSED MODELS OF MRP SYSTEMS CONSIDERING UNCERTAINTIES

    Directory of Open Access Journals (Sweden)

    Martín Dario Arango

    2012-12-01

    , delivery time and inventory availability. These parameters are processed by the fuzzy logic by modeling an MRP closed system deterministic. Therefore, three models are initially MRP closed system, where each independently consider uncertainty in capacity, delivery time and inventory availability. Also, we present a fourth model of MRP closed system jointly analyzes the uncertainty in the three parameters mentioned above. Each of these models is corroborated with information from a company in the Colombian electricity area, evaluating the total cost of the production plan, inventory levels, service level and computational complexity.

  17. Telecommuting. Factors to consider.

    Science.gov (United States)

    D'Arruda, K A

    2001-10-01

    1. Telecommuting is a work arrangement in which employees work part time or full time from their homes or smaller telework centers. They communicate with employers via computer. 2. Telecommuting can raise legal issues for companies. Can telecommuting be considered a reasonable accommodation under the Americans With Disabilities Act? When at home, is a worker injured within the course and scope of their employment for purposes of workers' compensation? 3. Occupational and environmental health nurses may need to alter existing programs to meet the distinct needs of telecommuters. Often, there are ergonomic issues and home office safety issues which are not of concern to other employees. Additionally, occupational and environmental health nurses may have to offer programs in new formats (e.g., Internet or Intranet programs) to effectively communicate with teleworkers.

  18. Grassland gross carbon dioxide uptake based on an improved model tree ensemble approach considering human interventions: global estimation and covariation with climate.

    Science.gov (United States)

    Liang, Wei; Lü, Yihe; Zhang, Weibin; Li, Shuai; Jin, Zhao; Ciais, Philippe; Fu, Bojie; Wang, Shuai; Yan, Jianwu; Li, Junyi; Su, Huimin

    2017-07-01

    Grassland ecosystems act as a crucial role in the global carbon cycle and provide vital ecosystem services for many species. However, these low-productivity and water-limited ecosystems are sensitive and vulnerable to climate perturbations and human intervention, the latter of which is often not considered due to lack of spatial information regarding the grassland management. Here by the application of a model tree ensemble (MTE-GRASS) trained on local eddy covariance data and using as predictors gridded climate and management intensity field (grazing and cutting), we first provide an estimate of global grassland gross primary production (GPP). GPP from our study compares well (modeling efficiency NSE = 0.85 spatial; NSE between 0.69 and 0.94 interannual) with that from flux measurement. Global grassland GPP was on average 11 ± 0.31 Pg C yr -1 and exhibited significantly increasing trend at both annual and seasonal scales, with an annual increase of 0.023 Pg C (0.2%) from 1982 to 2011. Meanwhile, we found that at both annual and seasonal scale, the trend (except for northern summer) and interannual variability of the GPP are primarily driven by arid/semiarid ecosystems, the latter of which is due to the larger variation in precipitation. Grasslands in arid/semiarid regions have a stronger (33 g C m -2  yr -1 /100 mm) and faster (0- to 1-month time lag) response to precipitation than those in other regions. Although globally spatial gradients (71%) and interannual changes (51%) in GPP were mainly driven by precipitation, where most regions with arid/semiarid climate zone, temperature and radiation together shared half of GPP variability, which is mainly distributed in the high-latitude or cold regions. Our findings and the results of other studies suggest the overwhelming importance of arid/semiarid regions as a control on grassland ecosystems carbon cycle. Similarly, under the projected future climate change, grassland ecosystems in these regions will

  19. Considering Collaborative Creativity

    DEFF Research Database (Denmark)

    Jensen, Thessa

    2014-01-01

    This article develops a framework for understanding the creation of online content on social media sites. Focusing on creativity and its social context, the study is narrowed to the field of fanfiction and fanfiction sites. Using the Systems Model of Creativity by Csiksze- ntmihalyi as a template......, this article analyses roles, processes, and products found in fanfiction communities and on fanfiction sites. The specific needs for motivation and support of especially the writer and the collective (Thomas & Brown, 2011) surrounding them are looked upon and compared to the present functionality and usability...

  20. Should psychotherapy consider reincarnation?

    Science.gov (United States)

    Peres, Julio F P

    2012-02-01

    There is increasing recognition of the need to take into account the cultural environment and belief systems of psychotherapy patients because these values reflect basic assumptions about man's nature and the cognitive references used to cope with psychological difficulties. Currently accepted psychotherapeutic approaches take no account of the belief in life after death held by most of the world's population. The World Values Survey (http://www.worldvaluessurvey.org) showed that there are large numbers of reincarnationists around the world, and whatever the reasons for believing in reincarnation, psychotherapeutic approaches should not ignore this significant group of people. Respect for patient opinions and subjective realities is a therapeutic need and an ethical duty, even though therapists may not share the same beliefs. Guidelines are suggested for professionals to develop collaborative models that help patients mobilize their intrinsic intelligence to find solutions to their complaints.

  1. BRICS To Be Considered?

    Directory of Open Access Journals (Sweden)

    Georgy Toloraya

    2016-09-01

    most efficient when the countries consolidate their positions in the Group of 20 or other international organizations and communities. BRICS positions have become very noticeable in such instances. However, the BRICS countries have not yet reached an adequate level of cooperating and promoting the irinterests in the United Nations, which could be considered one trouble spot for the group.This article presents a comprehensive analysis of various factors affecting the ongoing formation and development of the BRICS, and offers possible formats for its institutionalization, expansion with new members, and options for competing with the new structures of economic growth and regional trade and economic unions. It concludes that the BRICS should remain a strategic priority for Russia

  2. What should be considered if you decide to build your mathematical model for predicting the development of bacterial resistance? Recommendations based on a systematic review of the literature.

    Directory of Open Access Journals (Sweden)

    Maria eArepeva

    2015-04-01

    Full Text Available Acquired bacterial resistance is one of the causes of mortality and morbidity from infectious diseases. Mathematical modeling allows us to predict the spread of resistance and to some extent to control its dynamics. The purpose of this review was to examine existing mathematical models in order to understand pros and cons of currently used approaches and to build our own model. During the analysis, seven articles about the mathematical approaches to studying resistance that satisfied the inclusion / exclusion criteria were selected. All models were classified according to the approach used to study resistance in the presence of antibiotic and were analyzed in terms of our research. Some models require modifications associated with the specific of the research. Further work plan of model building is as follows: modify some models, according to our research, check all obtained models on our data, and select the optimal model or several models with the best quality of prediction. After that we would be able to build a model for the development of resistance using the obtained results.

  3. Programa computacional para o dimensionamento de colhedoras considerando a pontualidade na colheita de soja Computer model to select combine harvesters considering the timeliness of soybean

    Directory of Open Access Journals (Sweden)

    Iackson O. Borges

    2006-04-01

    Full Text Available A colheita de soja (Glycine max (L. Merril é uma operação crítica que pode sofrer atrasos resultando em perdas na quantidade e na qualidade do material colhido. Embora o valor das perdas seja desconhecido no País, os produtores empregam colhedoras com reserva de capacidade para concluir a operação no menor prazo possível. O excesso de capacidade aumenta os custos fixos e a falta dela aumenta os custos das perdas por atraso e, em ambos os casos, reduzem a renda líquida da operação, ao que se denomina custo de pontualidade. O problema do dimensionamento consiste em ajustar o custo do capital extra investido na capacidade da máquina para garantir a pontualidade e o custo das perdas por atraso, buscando maximizar a renda líquida. Devido à importância da cultura e da pontualidade, o objetivo deste trabalho foi avaliar a influência do atraso no dimensionamento da frota e no custo da operação de colheita. Para tanto, desenvolveu-se um modelo computacional em linguagem Borland® Delphi 5.0, em que a entrada de dados inclui os atributos da região agroclimática, da colhedora e das cultivares de soja. O resultado é a renda líquida como indicador da pontualidade na operação para a colhedora selecionada. O programa foi utilizado para simular cenários numa propriedade na região de Ponta Grossa - PR, e os valores obtidos revelaram que a frota de colhedoras da propriedade opera com capacidade ociosa, produzindo renda líquida abaixo do potencial.Soybean harvest is considered a critical operation that might suffer some delays causing a reduction in crop yield or quality. Although the value of losses is unknown in the country, combine harvesters with high capacity are applied by the producers and they aim to conclude the operation as fast as possible. If the harvesters have greater capacity than the required, the fixed cost is increased, and if it is the opposite, it might reduce the crop yield. In both cases, there is a decrease in

  4. A Modified McQuiston model for evaluating efficiency of wet fin considering effect of condensate film moving on fin surface

    International Nuclear Information System (INIS)

    Xu Xiangguo; Xia Liang; Chan Mingyin; Deng Shiming

    2008-01-01

    A modified McQuiston model for evaluating the wet fin efficiency of cooling and dehumidification coils has been developed by modifying the existing popular McQuiston model and is reported in this paper. The condensate film moving on fin surfaces and its impacts on heat transfer have been taken into account in deriving the governing equation for fin temperature, and consequently, the enthalpy change of the moving condensate film has been included in the governing equation for fin temperature. The modified McQuiston model was validated by comparing its predictions with those using the McQuiston model under the same operating and boundary conditions. It is expected that the modified McQuiston model developed can be applied not only to the commonly seen air cooling and dehumidification but also to certain special operations such as industrial steam condensation

  5. The Importance of Considering the Temporal Distribution of Climate Variables for Ecological-Economic Modeling to Calculate the Consequences of Climate Change for Agriculture

    Science.gov (United States)

    Plegnière, Sabrina; Casper, Markus; Hecker, Benjamin; Müller-Fürstenberger, Georg

    2014-05-01

    The basis of many models to calculate and assess climate change and its consequences are annual means of temperature and precipitation. This method leads to many uncertainties especially at the regional or local level: the results are not realistic or too coarse. Particularly in agriculture, single events and the distribution of precipitation and temperature during the growing season have enormous influences on plant growth. Therefore, the temporal distribution of climate variables should not be ignored. To reach this goal, a high-resolution ecological-economic model was developed which combines a complex plant growth model (STICS) and an economic model. In this context, input data of the plant growth model are daily climate values for a specific climate station calculated by the statistical climate model (WETTREG). The economic model is deduced from the results of the plant growth model STICS. The chosen plant is corn because corn is often cultivated and used in many different ways. First of all, a sensitivity analysis showed that the plant growth model STICS is suitable to calculate the influences of different cultivation methods and climate on plant growth or yield as well as on soil fertility, e.g. by nitrate leaching, in a realistic way. Additional simulations helped to assess a production function that is the key element of the economic model. Thereby the problems when using mean values of temperature and precipitation in order to compute a production function by linear regression are pointed out. Several examples show why a linear regression to assess a production function based on mean climate values or smoothed natural distribution leads to imperfect results and why it is not possible to deduce a unique climate factor in the production function. One solution for this problem is the additional consideration of stress indices that show the impairment of plants by water or nitrate shortage. Thus, the resulting model takes into account not only the ecological

  6. A Novel 3D Thermal Impedance Model for High Power Modules Considering Multi-layer Thermal Coupling and Different Heating/Cooling Conditions

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2015-01-01

    accurate temperature estimation either vertically or horizontally inside the power devices is still hard to identify. This paper investigates the thermal behavior of high power module in various operating conditions by means of Finite Element Method (FEM). A novel 3D thermal impedance network considering......Thermal management of power electronic devices is essential for reliable performance especially at high power levels. One of the most important activities in the thermal management and reliability improvement is acquiring the temperature information in critical points of the power module. However...

  7. Pollen-Based Inverse Modelling versus Data Assimilation, two Different Ways to Consider Priors in Paleoclimate Reconstruction: Application to the Mediterranean Holocene

    Science.gov (United States)

    Guiot, J.

    2017-12-01

    In the last decades, climate reconstruction has much evolved. A important step has been passed with inverse modelling approach proposed by Guiot et al (2000). It is based on appropriate algorithms in the frame of the Bayesian statistical theory to estimate the inputs of a vegetation model when the outputs are known. The inputs are the climate variables that we want to reconstruct and the outputs are vegetation characteristics, which can be compared to pollen data. The Bayesian framework consists in defining prior distribution of the wanted climate variables and in using data and a model to estimate posterior probability distribution. The main interest of the method is the possibility to set different values of exogenous variables as the atmospheric CO2 concentration. The fact that the CO2 concentration has an influence on the photosynthesis and that its level is different between the calibration period (the 20th century) and the past, there is an important risk of biases on the reconstructions. After that initial paper, numerous papers have been published showing the interested of the method. In that approach, the prior distribution is fixed by educated guess of by using complementary information on the expected climate (other proxies or other records). In the data assimilation approach, the prior distribution is provided by a climate model. The use of a vegetation model together with proxy data, enable to calculate posterior distributions. Data assimilation consists in constraining climate model to reproduce estimates relatively close to the data, taking into account the respective errors of the data and of the climate model (Dubinkina et al, 2011). We compare both approaches using pollen data for the Holocene from the Mediterranean. Pollen data have been extracted from the European Pollen Database. The earth system model, LOVECLIM, is run to simulate Holocene climate with appropriate boundary conditions and realistic forcing. Simulated climate variables

  8. A conflict-resolution model for the conjunctive use of surface and groundwater resources that considers water-quality issues: a case study.

    Science.gov (United States)

    Bazargan-Lari, Mohammad Reza; Kerachian, Reza; Mansoori, Abbas

    2009-03-01

    The conjunctive use of surface and groundwater resources is one alternative for optimal use of available water resources in arid and semiarid regions. The optimization models proposed for conjunctive water allocation are often complicated, nonlinear, and computationally intensive, especially when different stakeholders are involved that have conflicting interests. In this article, a new conflict-resolution methodology developed for the conjunctive use of surface and groundwater resources using Nondominated Sorting Genetic Algorithm II (NSGA-II) and Young Conflict-Resolution Theory (YCRT) is presented. The proposed model is applied to the Tehran aquifer in the Tehran metropolitan area of Iran. Stakeholders in the study area have conflicting interests related to water supply with acceptable quality, pumping costs, groundwater quality, and groundwater table fluctuations. In the proposed methodology, MODFLOW and MT3D groundwater quantity and quality simulation models are linked with the NSGA-II optimization model to develop Pareto fronts among the objectives. The best solutions on the Pareto fronts are then selected using YCRT. The results of the proposed model show the significance of applying an integrated conflict-resolution approach to conjunctive use of surface and groundwater resources in the study area.

  9. Modelling of fluid flow phenomenon in laser+GMAW hybrid welding of aluminum alloy considering three phase coupling and arc plasma shear stress

    Science.gov (United States)

    Xu, Guoxiang; Li, Pengfei; Cao, Qingnan; Hu, Qingxian; Gu, Xiaoyan; Du, Baoshuai

    2018-03-01

    The present study aims to develop a unified three dimensional numerical model for fiber laser+GMAW hybrid welding, which is used to study the fluid flow phenomena in hybrid welding of aluminum alloy and the influence of laser power on weld pool dynamic behavior. This model takes into account the coupling of gas, liquid and metal phases. Laser heat input is described using a cone heat source model with changing peak power density, its height being determined based on the keyhole size. Arc heat input is modeled as a double ellipsoid heat source. The arc plasma flow and droplet transfer are simulated through the two simplified models. The temperature and velocity fields for different laser powers are calculated. The computed results are in general agreement with the experimental data. Both the peak and average values of fluid flow velocity during hybrid welding are much higher than those of GMAW. At a low level of laser power, both the arc force and droplet impingement force play a relatively large role on fluid flow in the hybrid welding. Keyhole depth always oscillates within a range. With an increase in laser power, the weld pool behavior becomes more complex. An anti-clockwise vortex is generated and the stability of keyhole depth is improved. Besides, the effects of laser power on different driving forces of fluid flow in weld pool are also discussed.

  10. Smaller global and regional carbon emissions from gross land use change when considering sub-grid secondary land cohorts in a global dynamic vegetation model

    Science.gov (United States)

    Yue, Chao; Ciais, Philippe; Li, Wei

    2018-02-01

    Several modelling studies reported elevated carbon emissions from historical land use change (ELUC) by including bidirectional transitions on the sub-grid scale (termed gross land use change), dominated by shifting cultivation and other land turnover processes. However, most dynamic global vegetation models (DGVMs) that have implemented gross land use change either do not account for sub-grid secondary lands, or often have only one single secondary land tile over a model grid cell and thus cannot account for various rotation lengths in shifting cultivation and associated secondary forest age dynamics. Therefore, it remains uncertain how realistic the past ELUC estimations are and how estimated ELUC will differ between the two modelling approaches with and without multiple sub-grid secondary land cohorts - in particular secondary forest cohorts. Here we investigated historical ELUC over 1501-2005 by including sub-grid forest age dynamics in a DGVM. We run two simulations, one with no secondary forests (Sageless) and the other with sub-grid secondary forests of six age classes whose demography is driven by historical land use change (Sage). Estimated global ELUC for 1501-2005 is 176 Pg C in Sage compared to 197 Pg C in Sageless. The lower ELUC values in Sage arise mainly from shifting cultivation in the tropics under an assumed constant rotation length of 15 years, being 27 Pg C in Sage in contrast to 46 Pg C in Sageless. Estimated cumulative ELUC values from wood harvest in the Sage simulation (31 Pg C) are however slightly higher than Sageless (27 Pg C) when the model is forced by reconstructed harvested areas because secondary forests targeted in Sage for harvest priority are insufficient to meet the prescribed harvest area, leading to wood harvest being dominated by old primary forests. An alternative approach to quantify wood harvest ELUC, i.e. always harvesting the close-to-mature forests in both Sageless and Sage, yields similar values of 33 Pg C by both

  11. Modelling Salmonella concentration throughout the pork supply chain by considering growth and survival in fluctuating conditions of temperature, pH and a(w).

    Science.gov (United States)

    Pin, Carmen; Avendaño-Perez, Gaspar; Cosciani-Cunico, Elena; Gómez, Natalia; Gounadakic, Antonia; Nychas, George-John; Skandamis, Panos; Barker, Gary

    2011-03-01

    We aim to predict the population density of Salmonella spp. through the pork supply chain under dynamic environmental conditions (pH, a(w) and temperature) that fluctuate from growth to survival/slow inactivation. To do this, the dependence of the probability of growth, and of the growth and inactivation rate on the temperature, pH and a(w) were modelled. Probabilistic and kinetic measurements, i.e. growth and survival curves, were collected from the ComBase database (www.combase.cc). Conditions at which selected data used to fit the models were generated covered wide ranges that are relevant to the pork supply chain. Probabilistic and kinetic models were combined to give predictions on the concentration of Salmonella spp. at any stage of the pork supply chain under fluctuating pH, a(w) and/or temperature. Models were implemented in a user-friendly computing tool freely available from http://www.ifr.ac.uk/safety/SalmonellaPredictions/. This program provides estimates on the population dynamics of Salmonella spp. at any stage of the pork supply chain and its predictive performance has been validated in several pork products. Copyright © 2010 Elsevier B.V. All rights reserved.

  12. The neural diathesis-stress model of schizophrenia revisited: An update on recent findings considering illness stage and neurobiological and methodological complexities.

    Science.gov (United States)

    Pruessner, Marita; Cullen, Alexis E; Aas, Monica; Walker, Elaine F

    2017-02-01

    Over the past decade, our understanding of the role of stress in serious mental illness has become more sophisticated. In this paper, we revisit the neural diathesis-stress model of schizophrenia that was initially proposed in 1997 and updated in 2008. In light of cumulative research findings, we must now encompass evidence on the premorbid periods of psychosis, and our more nuanced understanding of hypothalamic-pituitary-adrenal (HPA) axis function and its association with neurodevelopmental, epigenetic, neurotransmitter, and inflammatory processes, as well as brain structure and function. Giving consideration to the methodological complexities that have become more apparent as research in this area has burgeoned, the various indices of HPA axis function, and the different stages of illness, we review relevant research published since the 2008 update of the model. We conclude by proposing an extended neural diathesis-stress model that addresses the broader neurobiological context of stress psychobiology in psychosis progression. Implications of this model for best practice, with regards to both future research and treatment strategies, are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Considering direct and indirect habitat influences on stream biota in eco-geomorphology research to better understand, model, and manage riverine ecosystems

    Science.gov (United States)

    Cienciala, P.; Nelson, A. D.

    2017-12-01

    The field of fluvial eco-geomorphology strives to improve the understanding of interactions between physical and biological processes in running waters. This body of research has greatly contributed to the advancement of integrated river science and management. Arguably, the most popular research themes in eco-geomorphology include hydrogemorphic controls of habitat quality and effects of disturbances such as floods, sediment transport events or sediment accumulation. However, in contrast to the related field of ecology, the distinction between direct and indirect mechanisms which may affect habitat quality and biotic response to disturbance has been poorly explored in eco-geomorphic research. This knowledge gap poses an important challenge for interpretations of field observations and model development. In this research, using the examples of benthic invertebrates and fish, we examine the importance of direct and indirect influences that geomorphic and hydraulic processes may exert on stream biota. We also investigate their implications for modeling of organism-habitat relationships. To achieve our goal, we integrate field and remote sensing data from montane streams in the Pacific Northwest region with habitat models. Preliminary results indicate that indirect hydrogeomorphic influences of stream organisms, such as those mediated by altered availability of food resources, can be as important as direct influences (e.g. physical disturbance). We suggest that these findings may also have important implications for modeling of riverine habitat.

  14. Numerical Modelling of the Dynamic Response of High-Speed Railway Bridges Considering Vehicle-Structure and Structure-Soil-Structure Interaction

    DEFF Research Database (Denmark)

    Bucinskas, Paulius; Agapii, L.; Sneideris, J.

    2015-01-01

    The aim of this paper is the dynamic analysis of a multi-support bridge structure exposed to high-speed railway traffic. The proposed computational model has a unified approach for simultaneously accounting for the bridge structure response, soil response and forces induced by the vehicle...... by the bridge displacements and track unevenness together with the frequency-domain solution of the bridge structure coupled with the subsoil. The effects caused by different soil properties and stratification, as well as different vehicle speeds are determined and compared........ The bridge structure is modelled in three dimensions based on the finite element method using two-noded three-dimensional beam elements. The track structure is composed of three layers: rail, sleepers and deck which are connected through spring-dashpot systems. The vehicle travelling along a bridge...

  15. An EOQ model for time-dependent deteriorating items with alternating demand rates allowing shortages by considering time value of money

    Directory of Open Access Journals (Sweden)

    Kundu Antara

    2013-01-01

    Full Text Available The present paper deals with an economic order quantity (EOQ model of an inventory problem with alternating demand rate: (i For a certain period, the demand rate is a non linear function of the instantaneous inventory level. (ii For the rest of the cycle, the demand rate is time dependent. The time at which demand rate changes, may be deterministic or uncertain. The deterioration rate of the item is time dependent. The holding cost and shortage cost are taken as a linear function of time. The total cost function per unit time is obtained. Finally, the model is solved using a gradient based non-linear optimization technique (LINGO and is illustrated by a numerical example.

  16. Modeling and projecting land-use and land-cover changes with Cellular Automaton in considering landscape trajectories : An improvement for simulation of plausible future states

    OpenAIRE

    Houet , Thomas; Hubert-Moy , Laurence

    2006-01-01

    International audience; The modeling and projecting of land use change is essential to the assessment of consequent environmental impacts. In agricultural landscapes, land use patterns nearly always exhibit spatial autocorrelation, that is due in large part, to the clustered distribution of landscape features as hedgerows and wetlands, and also to the spatial interactions between land uses types itself. The importance of such structural spatial dependencies has to be taken into account when c...

  17. Atmospheric Cosmic-Ray Variation and Ambient Dose Equivalent Assessments Considering Ground Level Enhancement Thanks to Coupled Anisotropic Solar Cosmic Ray and Extensive Air Shower Modeling.

    Science.gov (United States)

    Hubert, Guillaume; Aubry, Sébastien

    2017-11-01

    This work investigates the impact of Forbush decrease (FD) and ground-level enhancement (GLE) in the atmosphere, based on solar and galactic cosmic-ray models and the extensive air shower simulations. This approach gives the possibility to investigate both the dynamic behavior of neutron monitors (NM) (using response function) and the flight dose. The ambient dose equivalent during quiet solar activity and solar events (i.e., FDs and GLEs) were investigated for realistic flight plans issued from the Eurocontrol Demand Data Repository. The calculated ambient dose equivalents were compared with flight measurements in quiet solar conditions; comparisons are relevant and demonstrate the ability to estimate the dose level. The GLE model was validated for the GLEs 5 and 69 using the cosmic-ray variation recorded by NMs. The GLE model was applied to flight dose calculations. All of these results show that dose values vary drastically with the route path (latitude, longitude and altitude) and with the delay between the flight departure and the solar event occurrence. Doses induced by extreme GLE events were investigated specifically for London to New York flights, and resulting additional doses are a few hundred or 1,000 μSv, impacting significantly the annual effective dose. This highlights the importance of monitoring extreme solar events and using realistic semi-empirical and particle transport methods for reliable calculation of dose levels.

  18. Comment on “A model for phosphate glass topology considering the modifying ion sub-network” [J. Chem. Phys. 140, 154501 (2014)

    International Nuclear Information System (INIS)

    Sidebottom, David L.

    2015-01-01

    In a recent paper, Hermansen, Mauro, and Yue [J. Chem. Phys. 140, 154501 (2014)] applied the temperature-dependent constraint theory to model both the glass transition temperature, T g , and fragility, m, of a series of binary alkali phosphate glasses of the form (R 2 O) x (P 2 O 5 ) 1−x , where R represents an alkali species. Key to their success seems to be the retention of linear constraints between the alkali ion (R + ) and the non-bridging oxygens near T g , which allows the model to mimic a supposed minimum for both T g (x) and m(x) located near x = 0.2. However, the authors have overlooked several recent studies that clearly show there is no minimum in m(x). We argue that the retention of the alkali ion constraints at these temperatures is unjustified and question whether the model calculations can be revised to meet the actual experimental data. We also discuss alternative interpretations for the fragility based on two-state thermodynamics that can accurately account for its compositional dependence

  19. Modeling Power Plant Cooling Water Requirements: A Regional Analysis of the Energy-Water Nexus Considering Renewable Sources within the Power Generation Mix

    Science.gov (United States)

    Peck, Jaron Joshua

    Water is used in power generation for cooling processes in thermoelectric power. plants and currently withdraws more water than any other sector in the U.S. Reducing water. use from power generation will help to alleviate water stress in at risk areas, where droughts. have the potential to strain water resources. The amount of water used for power varies. depending on many climatic aspects as well as plant operation factors. This work presents. a model that quantifies the water use for power generation for two regions representing. different generation fuel portfolios, California and Utah. The analysis of the California Independent System Operator introduces the methods. of water energy modeling by creating an overall water use factor in volume of water per. unit of energy produced based on the fuel generation mix of the area. The idea of water. monitoring based on energy used by a building or region is explored based on live fuel mix. data. This is for the purposes of increasing public awareness of the water associated with. personal energy use and helping to promote greater energy efficiency. The Utah case study explores the effects more renewable, and less water-intensive, forms of energy will have on the overall water use from power generation for the state. Using a similar model to that of the California case study, total water savings are quantified. based on power reduction scenarios involving increased use of renewable energy. The. plausibility of implementing more renewable energy into Utah’s power grid is also. discussed. Data resolution, as well as dispatch methods, economics, and solar variability, introduces some uncertainty into the analysis.

  20. Oxygen Distributions-Evaluation of Computational Methods, Using a Stochastic Model for Large Tumour Vasculature, to Elucidate the Importance of Considering a Complete Vascular Network.

    Directory of Open Access Journals (Sweden)

    Jakob H Lagerlöf

    Full Text Available To develop a general model that utilises a stochastic method to generate a vessel tree based on experimental data, and an associated irregular, macroscopic tumour. These will be used to evaluate two different methods for computing oxygen distribution.A vessel tree structure, and an associated tumour of 127 cm3, were generated, using a stochastic method and Bresenham's line algorithm to develop trees on two different scales and fusing them together. The vessel dimensions were adjusted through convolution and thresholding and each vessel voxel was assigned an oxygen value. Diffusion and consumption were modelled using a Green's function approach together with Michaelis-Menten kinetics. The computations were performed using a combined tree method (CTM and an individual tree method (ITM. Five tumour sub-sections were compared, to evaluate the methods.The oxygen distributions of the same tissue samples, using different methods of computation, were considerably less similar (root mean square deviation, RMSD≈0.02 than the distributions of different samples using CTM (0.001< RMSD<0.01. The deviations of ITM from CTM increase with lower oxygen values, resulting in ITM severely underestimating the level of hypoxia in the tumour. Kolmogorov Smirnov (KS tests showed that millimetre-scale samples may not represent the whole.The stochastic model managed to capture the heterogeneous nature of hypoxic fractions and, even though the simplified computation did not considerably alter the oxygen distribution, it leads to an evident underestimation of tumour hypoxia, and thereby radioresistance. For a trustworthy computation of tumour oxygenation, the interaction between adjacent microvessel trees must not be neglected, why evaluation should be made using high resolution and the CTM, applied to the entire tumour.

  1. A New Reliability Analysis Model of the Chegongzhuang Heat-Supplying Tunnel Structure Considering the Coupling of Pipeline Thrust and Thermal Effect

    Directory of Open Access Journals (Sweden)

    Jiawen Zhang

    2018-02-01

    Full Text Available Based on the operating Chegongzhuang heat-supplying tunnel in Beijing, the reliability of its lining structure under the action of large thrust and thermal effect is studied. According to the characteristics of a heat-supplying tunnel service, a three-dimensional numerical analysis model was established based on the mechanical tests on the in-situ specimens. The stress and strain of the tunnel structure were obtained before and after the operation. Compared with the field monitoring data, the rationality of the model was verified. After extracting the internal force of the lining structure, the improved method of subset simulation was proposed as the performance function to calculate the reliability of the main control section of the tunnel. In contrast to the traditional calculation method, the analytic relationship between the sample numbers in the subset simulation method and Monte Carlo method was given. The results indicate that the lining structure is greatly influenced by coupling in the range of six meters from the fixed brackets, especially the tunnel floor. The improved subset simulation method can greatly save computation time and improve computational efficiency under the premise of ensuring the accuracy of calculation. It is suitable for the reliability calculation of tunnel engineering, because “the lower the probability, the more efficient the calculation.”

  2. Response to health insurance by previously uninsured rural children.

    Science.gov (United States)

    Tilford, J M; Robbins, J M; Shema, S J; Farmer, F L

    1999-08-01

    To examine the healthcare utilization and costs of previously uninsured rural children. Four years of claims data from a school-based health insurance program located in the Mississippi Delta. All children who were not Medicaid-eligible or were uninsured, were eligible for limited benefits under the program. The 1987 National Medical Expenditure Survey (NMES) was used to compare utilization of services. The study represents a natural experiment in the provision of insurance benefits to a previously uninsured population. Premiums for the claims cost were set with little or no information on expected use of services. Claims from the insurer were used to form a panel data set. Mixed model logistic and linear regressions were estimated to determine the response to insurance for several categories of health services. The use of services increased over time and approached the level of utilization in the NMES. Conditional medical expenditures also increased over time. Actuarial estimates of claims cost greatly exceeded actual claims cost. The provision of a limited medical, dental, and optical benefit package cost approximately $20-$24 per member per month in claims paid. An important uncertainty in providing health insurance to previously uninsured populations is whether a pent-up demand exists for health services. Evidence of a pent-up demand for medical services was not supported in this study of rural school-age children. States considering partnerships with private insurers to implement the State Children's Health Insurance Program could lower premium costs by assembling basic data on previously uninsured children.

  3. Radiation Effects Investigations Based on Atmospheric Radiation Model (ATMORAD) Considering GEANT4 Simulations of Extensive Air Showers and Solar Modulation Potential.

    Science.gov (United States)

    Hubert, Guillaume; Cheminet, Adrien

    2015-07-01

    The natural radiative atmospheric environment is composed of secondary cosmic rays produced when primary cosmic rays hit the atmosphere. Understanding atmospheric radiations and their dynamics is essential for evaluating single event effects, so that radiation risks in aviation and the space environment (space weather) can be assessed. In this article, we present an atmospheric radiation model, named ATMORAD (Atmospheric Radiation), which is based on GEANT4 simulations of extensive air showers according to primary spectra that depend only on the solar modulation potential (force-field approximation). Based on neutron spectrometry, solar modulation potential can be deduced using neutron spectrometer measurements and ATMORAD. Some comparisons between our methodology and standard approaches or measurements are also discussed. This work demonstrates the potential for using simulations of extensive air showers and neutron spectroscopy to monitor solar activity.

  4. Should orthopedic surgeons consider the effects of gabapentin administration on bone healing while treating a long bone fracture: experimental study in a rat model

    Directory of Open Access Journals (Sweden)

    Sofu Hakan

    2016-01-01

    Full Text Available Objective: The main purpose of the present study was to assess the radiographic, histological, and mechanical effects of gabapentin on fracture healing in a rat model of femur fracture. Materials and methods: A standard transverse fracture of the mid-diaphysis was created. A total of 60 female Wistar-Albino rats with the mean age of 13.5 ± 1.2 weeks were used for this experimental trial. The rats were randomized into four groups with 15 animals included in each group. Group A and B were the control groups whereas C and D were the treatment groups. Drugs were delivered by oral gavage twice a day with the daily dosage calculated according to body surface area conversion to the human equivalent dosing regimen of 1200 mg/day. Radiographic, histological, and biomechanical evaluation was performed. Results: We could not detect any statistically significant difference between the control and gabapentin treatment groups according to the comparative assessment of radiographic scores on the 15th and 30th days. Although no significant differences were found between the groups on the 15th day, histological scores were better in the control group on the 30th day. According to the results of biomechanical testing, the fractured femurs resected from the control group exhibited significantly more strength on the 30th day. Conclusions: According to the data we acquired during the present study, administration of gabapentin negatively affects the fracture healing process especially in the aspects of histological progression as well as the biomechanical strength of the callus in a rat model.

  5. High-frequency modelling of a three-phase pulse width modulation inverter towards the dc bus considering line and controller harmonics

    Directory of Open Access Journals (Sweden)

    Saeid Haghbin

    2014-10-01

    Full Text Available Closed-form analytical formulas are provided to calculate the dc bus harmonics of a three-phase sinusoidal pulse width modulation (SPWM inverter. The harmonic analysis is performed by using a double Fourier series approach to determine the dc bus current frequency spectrum. For an arbitrary modulation index and load power factor, the full harmonic components of the inverter dc side current are calculated. Based on the developed analytical model, an equivalent circuit is proposed for the inverter harmonic analysis towards the dc bus. Moreover, the impacts of line harmonics and zero sequence injection in controller towards the dc bus are presented. The results show that the 5th and 7th ac line harmonics on the dc side current is appearance of the 6th harmonic in the dc side. The impact of zero sequence injection to the controller on the dc side is negligible. In addition to analytical formulation, different simulations and extensive measurements performed which the results verified the presented analytical framework.

  6. Forecasting Italian seismicity through a spatio-temporal physical model: importance of considering time-dependency and reliability of the forecast

    Directory of Open Access Journals (Sweden)

    Amir Hakimhashemi

    2010-11-01

    Full Text Available We apply here a forecasting model to the Italian region for the spatio-temporal distribution of seismicity based on a smoothing Kernel function, Coulomb stress variations, and a rate-and-state friction law. We tested the feasibility of this approach, and analyzed the importance of introducing time-dependency in forecasting future events. The change in seismicity rate as a function of time was estimated by calculating the Coulomb stress change imparted by large earthquakes. We applied our approach to the region of Italy, and used all of the cataloged earthquakes that occurred up to 2006 to generate the reference seismicity rate. For calculation of the time-dependent seismicity rate changes, we estimated the rate-and-state stress transfer imparted by all of the ML≥4.0 earthquakes that occurred during 2007 and 2008. To validate the results, we first compared the reference seismicity rate with the distribution of ML≥1.8 earthquakes since 2007, using both a non-declustered and a declustered catalog. A positive correlation was found, and all of the forecast earthquakes had locations within 82% and 87% of the study area with the highest seismicity rate, respectively. Furthermore, 95% of the forecast earthquakes had locations within 27% and 47% of the study area with the highest seismicity rate, respectively. For the time-dependent seismicity rate changes, the number of events with locations in the regions with a seismicity rate increase was 11% more than in the regions with a seismicity rate decrease.

  7. ESTRATÉGIA PARA MODELAGEM NUMÉRICA DE SISTEMAS MISTOS CONSIDERANDO DIFERENTES MODELOS DE RUPTURA PARA OS MATERIAIS STRATEGY FOR NUMERIC MODELLING OF COMPOSITE SYSTEMS CONSIDERING DIFFERENT MODELS OF RUPTURE FOR THE MATERIALS

    Directory of Open Access Journals (Sweden)

    Julio Cesar Molina

    2009-08-01

    Full Text Available Este artigo apresenta a estratégia utilizada na modelagem numérica de um corpo-de-prova misto de madeira e concreto, com sistema de conexão metálico, sob carregamento. A modelagem do sistema foi efetuada a partir de um modelo tridimensional, que utiliza o software ANSYS, versão 10.0, que tem como base o Método dos Elementos Finitos, onde foram considerados diferentes modelos de ruptura para os materiais unidos, além de elementos de contato nas interfaces dos mesmos. Os elementos finitos, assim como os materiais utilizados, foram escolhidos em função de suas representatividades perante os comportamentos a serem simulados, para que, dessa forma, fosse possível a consideração de efeitos importantes como plasticidade e ortotropia para os materiais. Os resultados obtidos a partir da modelagem proposta foram comparados com os resultados experimentais de ensaios de cisalhamento, realizados em corpos-de-prova mistos com carregamento aplicado até a ruptura e o erro obtido, neste caso, foi de até 15%. A finalidade deste trabalho é servir de base para a modelagem de sistemas estruturais, presentes em diversas áreas da engenharia, dentre elas, mecânica e civil, onde são utilizados materiais com diferentes comportamentos estruturais. A modelagem proposta possibilita a análise global do modelo assim como a análise dos aspectos localizados de interesse como a concentração de tensões, efeito de difícil quantificação em uma análise experimental.This paper shows the strategy used in the numeric modeling of a composite specimen of wood and concrete, with metallic connection system, with applied cyclical load. The modeling of the system was made starting from a three-dimensional model, using the software ANSYS, version 10.0, that has as base the Method of the Finite Elements, in which different rupture models were considered for the materials, besides contact elements in the interfaces of the materials. The finite elements, as well as the

  8. Influence of previous participation in physical activity on its ...

    African Journals Online (AJOL)

    ... participation can influence perceptions of PA among the students. Physical activity promotion programmes should consider the role of these factors which should be emphasised from childhood. Keywords: physical activity, students, perceived benefits, perceived barriers, previous participation, sedentary lifestyle, Rwanda

  9. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Fritz, S., E-mail: stefan.fritz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Vollherbst, D., E-mail: dominikvollherbst@web.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Zelzer, S., E-mail: s.zelzer@dkfz-heidelberg.de [German Cancer Research Center (dkfz), Medical and Biological Informatics (Germany); Wachter, M. F., E-mail: fredericwachter@googlemail.com; Bellemann, N., E-mail: nadine.bellemann@med.uni-heidelberg.de; Gockner, T., E-mail: theresa.gockner@med.uni-heidelberg.de; Mokry, T., E-mail: theresa.mokry@med.uni-heidelberg.de; Schmitz, A., E-mail: anne.schmitz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Aulmann, S., E-mail: sebastian.aulmann@mail.com [University Hospital Heidelberg, Department of General Pathology (Germany); Stampfl, U., E-mail: ulrike.stampfl@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P., E-mail: philippe.pereira@slk-kliniken.de [SLK Kliniken Heilbronn GmbH, Clinic for Radiology, Minimally-invasive Therapies and Nuclear Medicine (Germany); Kauczor, H. U., E-mail: hu.kauczor@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Werner, J., E-mail: jens.werner@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Radeleff, B. A., E-mail: boris.radeleff@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany)

    2015-02-15

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm{sup 3}, and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm{sup 3}, and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

  10. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    International Nuclear Information System (INIS)

    Sommer, C. M.; Fritz, S.; Vollherbst, D.; Zelzer, S.; Wachter, M. F.; Bellemann, N.; Gockner, T.; Mokry, T.; Schmitz, A.; Aulmann, S.; Stampfl, U.; Pereira, P.; Kauczor, H. U.; Werner, J.; Radeleff, B. A.

    2015-01-01

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm 3 , and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm 3 , and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver

  11. Prediction of Cone Crusher Performance Considering Liner Wear

    Directory of Open Access Journals (Sweden)

    Yanjun Ma

    2016-12-01

    Full Text Available Cone crushers are used in the aggregates and mining industries to crush rock material. The pressure on cone crusher liners is the key factor that influences the hydraulic pressure, power draw and liner wear. In order to dynamically analyze and calculate cone crusher performance along with liner wear, a series of experiments are performed to obtain the crushed rock material samples from a crushing plant at different time intervals. In this study, piston die tests are carried out and a model relating compression coefficient, compression ratio and particle size distribution to a corresponding pressure is presented. On this basis, a new wear prediction model is proposed combining the empirical model for predicting liner wear with time parameter. A simple and practical model, based on the wear model and interparticle breakage, is presented for calculating compression ratio of each crushing zone along with liner wear. Furthermore, the size distribution of the product is calculated based on existing size reduction process model. A method of analysis of product size distribution and shape in the crushing process considering liner wear is proposed. Finally, the validity of the wear model is verified via testing. The result shows that there is a significant improvement of the prediction of cone crusher performance considering liner wear as compared to the previous model.

  12. Congruency sequence effects are driven by previous-trial congruency, not previous-trial response conflict

    OpenAIRE

    Weissman, Daniel H.; Carp, Joshua

    2013-01-01

    Congruency effects in distracter interference tasks are often smaller after incongruent trials than after congruent trials. However, the sources of such congruency sequence effects (CSEs) are controversial. The conflict monitoring model of cognitive control links CSEs to the detection and resolution of response conflict. In contrast, competing theories attribute CSEs to attentional or affective processes that vary with previous-trial congruency (incongruent vs. congruent). The present study s...

  13. Wind Power Prediction Considering Nonlinear Atmospheric Disturbances

    OpenAIRE

    Yagang Zhang; Jingyun Yang; Kangcheng Wang; Zengping Wang

    2015-01-01

    This paper considers the effect of nonlinear atmospheric disturbances on wind power prediction. A Lorenz system is introduced as an atmospheric disturbance model. Three new improved wind forecasting models combined with a Lorenz comprehensive disturbance are put forward in this study. Firstly, we define the form of the Lorenz disturbance variable and the wind speed perturbation formula. Then, different artificial neural network models are used to verify the new idea and obtain better wind spe...

  14. A stochastic model for neutron simulation considering the spectrum and nuclear properties with continuous dependence of energy; Um modelo estocastico de simulacao neutronica considerando o espectro e propriedades nucleares com dependencia continua de energia

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Dayana Queiroz de

    2011-01-15

    This thesis has developed a stochastic model to simulate the neutrons transport in a heterogeneous environment, considering continuous neutron spectra and the nuclear properties with its continuous dependence on energy. This model was implemented using Monte Carlo method for the propagation of neutrons in different environment. Due to restrictions with respect to the number of neutrons that can be simulated in reasonable computational processing time introduced the variable control volume along the (pseudo-) periodic boundary conditions in order to overcome this problem. The choice of class physical Monte Carlo is due to the fact that it can decompose into simpler constituents the problem of solve a transport equation. The components may be treated separately, these are the propagation and interaction while respecting the laws of energy conservation and momentum, and the relationships that determine the probability of their interaction. We are aware of the fact that the problem approached in this thesis is far from being comparable to building a nuclear reactor, but this discussion the main target was to develop the Monte Carlo model, implement the code in a computer language that allows extensions of modular way. This study allowed a detailed analysis of the influence of energy on the neutron population and its impact on the life cycle of neutrons. From the results, even for a simple geometrical arrangement, we can conclude the need to consider the energy dependence, i.e. an spectral effective multiplication factor should be introduced each energy group separately. (author)

  15. Placental complications after a previous cesarean section

    OpenAIRE

    Milošević Jelena; Lilić Vekoslav; Tasić Marija; Radović-Janošević Dragana; Stefanović Milan; Antić Vladimir

    2009-01-01

    Introduction The incidence of cesarean section has been rising in the past 50 years. With the increased number of cesarean sections, the number of pregnancies with the previous cesarean section rises as well. The aim of this study was to establish the influence of the previous cesarean section on the development of placental complications: placenta previa, placental abruption and placenta accreta, as well as to determine the influence of the number of previous cesarean sections on the complic...

  16. Tempo curves considered harmful (part 2)

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1991-01-01

    A column (the second of a series of three) constitutes an abridged and adapted version of Tempo curves considered harmful . M (an amateur mathematician) and P (a would-be psychologist) incorporated some generative models for expressive timing in their sequencer program. This proved partially

  17. Implant breast reconstruction after salvage mastectomy in previously irradiated patients.

    Science.gov (United States)

    Persichetti, Paolo; Cagli, Barbara; Simone, Pierfranco; Cogliandro, Annalisa; Fortunato, Lucio; Altomare, Vittorio; Trodella, Lucio

    2009-04-01

    The most common surgical approach in case of local tumor recurrence after quadrantectomy and radiotherapy is salvage mastectomy. Breast reconstruction is the subsequent phase of the treatment and the plastic surgeon has to operate on previously irradiated and manipulated tissues. The medical literature highlights that breast reconstruction with tissue expanders is not a pursuable option, considering previous radiotherapy a contraindication. The purpose of this retrospective study is to evaluate the influence of previous radiotherapy on 2-stage breast reconstruction (tissue expander/implant). Only patients with analogous timing of radiation therapy and the same demolitive and reconstructive procedures were recruited. The results of this study prove that, after salvage mastectomy in previously irradiated patients, implant reconstruction is still possible. Further comparative studies are, of course, advisable to draw any conclusion on the possibility to perform implant reconstruction in previously irradiated patients.

  18. Expression of glial fibrillar acidic protein in the sensorimotor cortex of the cerebral hemispheres in the modeling of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection

    OpenAIRE

    Yaremenko, L. M.; Grabovoy, A. N.; Shepelev, S.E.

    2017-01-01

    Aim. In order to analyze the dynamics of expression of glial fibrillar acidic protein in the sensorimotor cortex of the large hemispheres in the simulation of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection.Materials and methods. The study is conducted on 185 male mature white rats from Wistar line weighing 260-290 g, in which the damage of the brain was modulated. The brain for study was taken on the 1st, 3rd, 10th, 30th and 90th days...

  19. Expression of glial fibrillar acidic protein in the sensorimotor cortex of the cerebral hemispheres in the modeling of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection

    OpenAIRE

    L. M. Yaremenko; A. N. Grabovoy; S. E. Shepelev

    2017-01-01

    Aim. In order to analyze the dynamics of expression of glial fibrillar acidic protein in the sensorimotor cortex of the large hemispheres in the simulation of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection. Materials and methods. The study is conducted on 185 male mature white rats from Wistar line weighing 260-290 g, in which the damage of the brain was modulated. The brain for study was taken on the 1st, 3rd, 10th, 30th and 90th...

  20. Should Euthanasia Be Considered Iatrogenic?

    Science.gov (United States)

    Barone, Silvana; Unguru, Yoram

    2017-08-01

    As more countries adopt laws and regulations concerning euthanasia, pediatric euthanasia has become an important topic of discussion. Conceptions of what constitutes harm to patients are fluid and highly dependent on a myriad of factors including, but not limited to, health care ethics, family values, and cultural context. Euthanasia could be viewed as iatrogenic insofar as it results in an outcome (death) that some might consider inherently negative. However, this perspective fails to acknowledge that death, the outcome of euthanasia, is not an inadvertent or preventable complication but rather the goal of the medical intervention. Conversely, the refusal to engage in the practice of euthanasia might be conceived as iatrogenic insofar as it might inadvertently prolong patient suffering. This article will explore cultural and social factors informing families', health care professionals', and society's views on pediatric euthanasia in selected countries. © 2017 American Medical Association. All Rights Reserved.

  1. The US considers consumer choice

    International Nuclear Information System (INIS)

    McCaughey, John.

    1996-01-01

    About half the states in the USA are seriously considering giving domestic customers the right to choose their own gas supplier as large consumers have been able to for years. This is referred to as ''unbundling''. Of the 1400 or so natural gas local distribution companies (LDCs), about one third appear to support unbundling, another third are opposed and the remainder are uncertain; small and medium sized LDCs are most likely to be opposed. A number of state regulators are also ambivalent or actively hostile to the idea. The LDCs supply consumers with gas at the price the LDC pays for it. Their profits are made from connections and the transport of as large a volume of gas as possible for which the supplier pays passthrough charges. The complex arguments as to whether unbundling will prove favourable to the LDCs and what benefits and disadvantages there may be for customers are examined. (UK)

  2. PEAK SHAVING CONSIDERING STREAMFLOW UNCERTAINTIES

    African Journals Online (AJOL)

    user

    Abstract. The main thrust of this paper is peak shaving with a Stochastic hydro model. In peak sharing, the amount of hydro energy scheduled may be a minimum but it serves to replace less efficient thermal units. The sample system is die Kainji hydro plant and the thermal units of the National Electric. Power Authority.

  3. [Considering all facets of man].

    Science.gov (United States)

    Quentin, Bertrand

    2012-01-01

    Michel Foucault and Erving Goffman, through their works, questioned the notion of mental illness as well as traditional psychiatry. However, Friedrich Hegel, in reference to Philippe Pinel and to "human treatment" is opposed to any unilateral model which would tend to exclude the institution, insanity and therefore the patient.

  4. Proposal of a mathematic program model for production development projects in E and P considering uncertainties; Proposta de um modelo de programacao matematica para projetos de desenvolvimento da producao em E e P considerando incertezas

    Energy Technology Data Exchange (ETDEWEB)

    Kahn, Marcio [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Hamacher, Silvio [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)

    2012-07-01

    A mathematical programming model to support the decision maker how to identify the optimal infrastructure design solution to the Development and Production of an oil field is proposed in this paper. The problem addressed is to maximize the economic return of the additional production of oil in a field with existing production infrastructure installed and as a proposed solution to this problem a model of mixed integer linear programming was developed. This formulation allows identifying the optimal level of exploration and production of a field subject to uncertainties. The variables to be defined are: Floating Production Units installed to be utilized and their oil production, the use of manifolds or not, and the number of wells that will be connected to the Floating Production Units. Finally, the model provides the optimal development plan with the best economic return considering the constraints and uncertainties of the problem. Besides the optimal solution, sensitivity analyzes were performed improving the understanding of the problem and providing useful information to the decision maker. (author)

  5. Bilateral orbital infarction and retinal detachment in a previously ...

    African Journals Online (AJOL)

    In this report, we present a case of an 11‑year‑old previously undiagnosed sickle cell disease Nigerian girl with severe acute bilateral orbital infarction and retinal detachment to highlight that hemoglobinopathy induced orbital infarction should be considered in African children with acute onset proptosis with or without ...

  6. Automatic electromagnetic valve for previous vacuum

    International Nuclear Information System (INIS)

    Granados, C. E.; Martin, F.

    1959-01-01

    A valve which permits the maintenance of an installation vacuum when electric current fails is described. It also lets the air in the previous vacuum bomb to prevent the oil ascending in the vacuum tubes. (Author)

  7. Expression of glial fibrillar acidic protein in the sensorimotor cortex of the cerebral hemispheres in the modeling of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection

    Directory of Open Access Journals (Sweden)

    L. M. Yaremenko

    2017-12-01

    Full Text Available Aim. In order to analyze the dynamics of expression of glial fibrillar acidic protein in the sensorimotor cortex of the large hemispheres in the simulation of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection. Materials and methods. The study is conducted on 185 male mature white rats from Wistar line weighing 260-290 g, in which the damage of the brain was modulated. The brain for study was taken on the 1st, 3rd, 10th, 30th and 90th days after the start of the experiment. The histological, immunohistochemical, morphometric and statistical methods were used. Results. Observations have shown that sensitization by the brain antigen causes neurodegenerative changes in the sensorimotor cortex and a moderate increase in the number of GFAP+-gliocytes, which is gradually increasing. The discirculatory changes that occurred with PO and BCA against the background of previous sensitization practically do not lead to changes in the number of GFAP+-cells. Against the background of sensitization by brain antigen, brain ischemia leads to an increase in the number of gliocytes that are GFAP labeled. In the affected hemisphere, their number reaches a maximum in the end of the acute period of ischemia, after which it decreases. But even in 3 months after transient vascular lesion, there are almost twice as many as in conditionally intact rats. This can be a factor that will significantly affect the function of brain regions after a vascular accident. The increase in the number of GFAP+-gliocytes in the contralateral hemisphere allows us to speak about a certain systemic response of astrocytic glia after ischemic trauma. An early reaction to increase of the number of labeled astrocytes just a day after ischemic attack suggests that some of this type of gliocytes does not expresses GFAP under normal conditions. The action of Imunofan in MEAs results in a less significant decrease in manifestations of

  8. Analysis of moving bottlenecks considering a triangular fundamental diagram

    Directory of Open Access Journals (Sweden)

    Karim Fadhloun

    2016-10-01

    Full Text Available A significant number of research efforts have studied and analyzed the case in which a vehicle is moving slower than the traffic stream. This phenomenon, known as a moving bottleneck, results in a disruption of traffic flow and may significantly impact the traffic stream behavior upstream, downstream and abreast the slow moving vehicle. In this paper, a macroscopic approach for modeling moving bottlenecks is developed using microscopically derived data considering a triangular fundamental diagram. The passing flow rates of different moving bottleneck scenarios are determined using a previously developed microscopic model based on simulated data derived from the INTEGRATION software. Using the simulation results, an explicit expression of the bottleneck diagram, a flow-density relationship that defines the phenomenon macroscopically is proposed and the behavior of the traffic stream downstream and abreast the moving obstruction is depicted. It is demonstrated that the behavior of the traffic stream downstream of the slow vehicle as well as the acceleration behavior while passing is governed by the demand level. Such a result is coherent and consistent, to a significant extent, with two decades of research related to modeling moving bottlenecks and constitutes a potential feasible and more detailed description of the phenomenon in the case of a triangular fundamental diagram. Finally, it is noteworthy that the research subject of this paper could be considered as a first step in developing a numerical and practitioner-friendly framework for the analysis of moving bottlenecks that does not involve approaching the problem from its theoretical perspective.

  9. Concomitant and previous osteoporotic vertebral fractures.

    Science.gov (United States)

    Lenski, Markus; Büser, Natalie; Scherer, Michael

    2017-04-01

    Background and purpose - Patients with osteoporosis who present with an acute onset of back pain often have multiple fractures on plain radiographs. Differentiation of an acute osteoporotic vertebral fracture (AOVF) from previous fractures is difficult. The aim of this study was to investigate the incidence of concomitant AOVFs and previous OVFs in patients with symptomatic AOVFs, and to identify risk factors for concomitant AOVFs. Patients and methods - This was a prospective epidemiological study based on the Registry of Pathological Osteoporotic Vertebral Fractures (REPAPORA) with 1,005 patients and 2,874 osteoporotic vertebral fractures, which has been running since February 1, 2006. Concomitant fractures are defined as at least 2 acute short-tau inversion recovery (STIR-) positive vertebral fractures that happen concomitantly. A previous fracture is a STIR-negative fracture at the time of initial diagnostics. Logistic regression was used to examine the influence of various variables on the incidence of concomitant fractures. Results - More than 99% of osteoporotic vertebral fractures occurred in the thoracic and lumbar spine. The incidence of concomitant fractures at the time of first patient contact was 26% and that of previous fractures was 60%. The odds ratio (OR) for concomitant fractures decreased with a higher number of previous fractures (OR =0.86; p = 0.03) and higher dual-energy X-ray absorptiometry T-score (OR =0.72; p = 0.003). Interpretation - Concomitant and previous osteoporotic vertebral fractures are common. Risk factors for concomitant fractures are a low T-score and a low number of previous vertebral fractures in cases of osteoporotic vertebral fracture. An MRI scan of the the complete thoracic and lumbar spine with STIR sequence reduces the risk of under-diagnosis and under-treatment.

  10. New slip control system considering actuator dynamics

    OpenAIRE

    Soltani, Amirmasoud; Assadian, Francis

    2015-01-01

    A new control strategy for wheel slip control, considering the complete dynamics of the electro-hydraulic brake (EHB) system, is developed and experimentally validated in Cranfield University's HiL system. The control system is based on closed loop shaping Youla-parameterization method. The plant model is linearized about the nominal operating point, a Youla parameter is defined for all stabilizing feedback controller and control performance is achieved by employing closed loop shaping techni...

  11. Delivery outcomes at term after one previous cesarean section.

    Science.gov (United States)

    Yamani-Zamzami, Tarik Y

    2007-12-01

    To determine the maternal and perinatal outcomes at term in women with one previous cesarean delivery and with no history of vaginal birth. This is a case-control study conducted at King Abdul-Aziz University Hospital, Jeddah, Kingdom of Saudi Arabia, between January 1, 1999 and December 31, 2002. One hundred sixty-two women with one previous cesarean delivery and with no previous vaginal birth were compared with 324 control women. The cesarean section rate was higher in the study group 40 (24.7%) versus 23 (7.1%) in the control group and was statistically significant (phistory of vaginal delivery are considered less favorable, the vaginal birth after cesarean section success rate may be even lower if the indication for previous primary cesarean delivery was failure to progress, and may be associated with increased risk of uterine rupture. Further study is required to confirm our findings.

  12. Uterine rupture without previous caesarean delivery

    DEFF Research Database (Denmark)

    Thisted, Dorthe L. A.; H. Mortensen, Laust; Krebs, Lone

    2015-01-01

    OBJECTIVE: To determine incidence and patient characteristics of women with uterine rupture during singleton births at term without a previous caesarean delivery. STUDY DESIGN: Population based cohort study. Women with term singleton birth, no record of previous caesarean delivery and planned...... vaginal delivery (n=611,803) were identified in the Danish Medical Birth Registry (1997-2008). Medical records from women recorded with uterine rupture during labour were reviewed to ascertain events of complete uterine rupture. Relative Risk (RR) and adjusted Relative Risk Ratio (aRR) of complete uterine...... rupture with 95% confidence intervals (95% CI) were ascertained according to characteristics of the women and of the delivery. RESULTS: We identified 20 cases with complete uterine rupture. The incidence of complete uterine rupture among women without previous caesarean delivery was about 3...

  13. INTRODUCTION Previous reports have documented a high ...

    African Journals Online (AJOL)

    pregnancy if they were married, educated, had dental insurance, previously used dental services when not pregnant, or had knowledge about the possible connection between oral health and pregnancy outcome8. The purpose of this study was to explore the factors determining good oral hygiene among pregnant women ...

  14. Empowerment perceptions of educational managers from previously ...

    African Journals Online (AJOL)

    The perceptions of educational manag ers from previously disadvantaged primary and high schools in the Nelson Mandela Metropole regarding the issue of empowerment are outlined and the perceptions of educational managers in terms of various aspects of empowerment at different levels reflected. A literature study ...

  15. Management of choledocholithiasis after previous gastrectomy.

    Science.gov (United States)

    Anwer, S; Egan, R; Cross, N; Guru Naidu, S; Somasekar, K

    2017-09-01

    Common bile duct stones in patients with a previous gastrectomy can be a technical challenge because of the altered anatomy. This paper presents the successful management of two such patients using non-traditional techniques as conventional endoscopic retrograde cholangiopancreatography was not possible.

  16. Laboratory Grouping Based on Previous Courses.

    Science.gov (United States)

    Doemling, Donald B.; Bowman, Douglas C.

    1981-01-01

    In a five-year study, second-year human physiology students were grouped for laboratory according to previous physiology and laboratory experience. No significant differences in course or board examination performance were found, though correlations were found between predental grade-point averages and grouping. (MSE)

  17. Comparing Consider-Covariance Analysis with Sigma-Point Consider Filter and Linear-Theory Consider Filter Formulations

    Science.gov (United States)

    Lisano, Michael E.

    2007-01-01

    Recent literature in applied estimation theory reflects growing interest in the sigma-point (also called unscented ) formulation for optimal sequential state estimation, often describing performance comparisons with extended Kalman filters as applied to specific dynamical problems [c.f. 1, 2, 3]. Favorable attributes of sigma-point filters are described as including a lower expected error for nonlinear even non-differentiable dynamical systems, and a straightforward formulation not requiring derivation or implementation of any partial derivative Jacobian matrices. These attributes are particularly attractive, e.g. in terms of enabling simplified code architecture and streamlined testing, in the formulation of estimators for nonlinear spaceflight mechanics systems, such as filter software onboard deep-space robotic spacecraft. As presented in [4], the Sigma-Point Consider Filter (SPCF) algorithm extends the sigma-point filter algorithm to the problem of consider covariance analysis. Considering parameters in a dynamical system, while estimating its state, provides an upper bound on the estimated state covariance, which is viewed as a conservative approach to designing estimators for problems of general guidance, navigation and control. This is because, whether a parameter in the system model is observable or not, error in the knowledge of the value of a non-estimated parameter will increase the actual uncertainty of the estimated state of the system beyond the level formally indicated by the covariance of an estimator that neglects errors or uncertainty in that parameter. The equations for SPCF covariance evolution are obtained in a fashion similar to the derivation approach taken with standard (i.e. linearized or extended) consider parameterized Kalman filters (c.f. [5]). While in [4] the SPCF and linear-theory consider filter (LTCF) were applied to an illustrative linear dynamics/linear measurement problem, in the present work examines the SPCF as applied to

  18. Wind Power Prediction Considering Nonlinear Atmospheric Disturbances

    Directory of Open Access Journals (Sweden)

    Yagang Zhang

    2015-01-01

    Full Text Available This paper considers the effect of nonlinear atmospheric disturbances on wind power prediction. A Lorenz system is introduced as an atmospheric disturbance model. Three new improved wind forecasting models combined with a Lorenz comprehensive disturbance are put forward in this study. Firstly, we define the form of the Lorenz disturbance variable and the wind speed perturbation formula. Then, different artificial neural network models are used to verify the new idea and obtain better wind speed predictions. Finally we separately use the original and improved wind speed series to predict the related wind power. This proves that the corrected wind speed provides higher precision wind power predictions. This research presents a totally new direction in the wind prediction field and has profound theoretical research value and practical guiding significance.

  19. Modélisation de la combustion de fuels lourds prenant en compte la dispersion des asphaltènes Modeling Heavy Fuel-Oil Combustion (While Considering Or Including Asphaltene Dispersion

    Directory of Open Access Journals (Sweden)

    Audibert F.

    2006-11-01

    difficultés relevant du mode d'exploration et de la non adéquation entre les structures asphalténiques et fractales. On a finalement opté pour une détermination visuelle s'appuyant sur les clichés sur lesquels les agglomérats d'asphaltènes sont clairement visualisés tels qu'ils sont dans le fuel. Ce mode d'exploration laborieux a cependant permis de déterminer un modèle construit sur une série de 25 fuels dont 10 ont été brûlés sur une chaudière de 2 MW, et 15 sur un four de 100 kW. Ce modèle fait intervenir les teneurs en carbone Conradson et en métaux, ainsi que le taux de dispersion des asphaltènes. Le perfectionnement des moyens d'exploration aidant, on peut s'attendre à ce que soient disponibles des techniques d'évaluation de la dispersion sur les clichés. Ce paramètre pourra alors être pris en considération pour une meilleure prédiction de résultats de combustion insuffisamment expliqués avec les paramètres classiques. Various models aiming to predict the amount of unburned particles (solids during heavy fuel-oil combustion have been developed. The parameters taken into consideration are generally asphaltenes precipitated by normal heptane or pentane and Conradson carbon as well as the metals content having a known catalytic effect on cenosphere combustion in the combustion chamber. The Exxon and Shell models can be mentioned, which were developed respectively in 1979 and 1981 (Chapter II. Other models also give consideration to the fuel-oil composition, the way it is atomized and diffused in the chamber and the combustion kinetics (research done by the MIT Energy Laboratory published in 1986. However, the above parameters are not the only ones involved. For some fuel oils, experience has shown that the state of dispersion of asphaltenes may also play an important role particularly for combustion installations with mechanical injection for which the dispersion of fuel-oil droplets is not very great and does not affect the structures built

  20. Previously unknown organomagnesium compounds in astrochemical context

    OpenAIRE

    Ruf, Alexander

    2018-01-01

    We describe the detection of dihydroxymagnesium carboxylates (CHOMg) in astrochemical context. CHOMg was detected in meteorites via ultrahigh-resolving chemical analytics and represents a novel, previously unreported chemical class. Thus, chemical stability was probed via quantum chemical computations, in combination with experimental fragmentation techniques. Results propose the putative formation of green-chemical OH-Grignard-type molecules and triggered fundamental questions within chemica...

  1. [Placental complications after a previous cesarean section].

    Science.gov (United States)

    Milosević, Jelena; Lilić, Vekoslav; Tasić, Marija; Radović-Janosević, Dragana; Stefanović, Milan; Antić, Vladimir

    2009-01-01

    The incidence of cesarean section has been rising in the past 50 years. With the increased number of cesarean sections, the number of pregnancies with the previous cesarean section rises as well. The aim of this study was to establish the influence of the previous cesarean section on the development of placental complications: placenta previa, placental abruption and placenta accreta, as well as to determine the influence of the number of previous cesarean sections on the complication development. The research was conducted at the Clinic of Gynecology and Obstetrics in Nis covering 10-year-period (from 1995 to 2005) with 32358 deliveries, 1280 deliveries after a previous cesarean section, 131 cases of placenta previa and 118 cases of placental abruption. The experimental groups was presented by the cases of placenta previa or placental abruption with prior cesarean section in obstetrics history, opposite to the control group having the same conditions but without a cesarean section in medical history. The incidence of placenta previa in the control group was 0.33%, opposite to the 1.86% incidence after one cesarean section (pcesarean sections and as high as 14.28% after three cesarean sections in obstetric history. Placental abruption was recorded as placental complication in 0.33% pregnancies in the control group, while its incidence was 1.02% after one cesarean section (pcesarean sections. The difference in the incidence of intrapartal hysterectomy between the group with prior cesarean section (0.86%) and without it (0.006%) shows a high statistical significance (pcesarean section is an important risk factor for the development of placental complications.

  2. Study on the Vehicle Dynamic Load Considering the Vehicle-Pavement Coupled Effect

    Science.gov (United States)

    Xu, H. L.; He, L.; An, D.

    2017-11-01

    The vibration of vehicle-pavement interaction system is sophisticated random vibration process and the vehicle-pavement coupled effect was not considered in the previous study. A new linear elastic model of the vehicle-pavement coupled system was established in the paper. The new model was verified with field measurement which could reflect the real vibration between vehicle and pavement. Using the new model, the study on the vehicle dynamic load considering the vehicle-pavement coupled effect showed that random forces (centralization) between vehicle and pavement were influenced largely by vehicle-pavement coupled effect. Numerical calculation indicated that the maximum of random forces in coupled model was 2.4 times than that in uncoupled model. Inquiring the reason, it was found that the main vibration frequency of the vehicle non-suspension system was similar with that of the vehicle suspension system in the coupled model and the resonance vibration lead to vehicle dynamic load increase significantly.

  3. Books average previous decade of economic misery.

    Science.gov (United States)

    Bentley, R Alexander; Acerbi, Alberto; Ormerod, Paul; Lampos, Vasileios

    2014-01-01

    For the 20(th) century since the Depression, we find a strong correlation between a 'literary misery index' derived from English language books and a moving average of the previous decade of the annual U.S. economic misery index, which is the sum of inflation and unemployment rates. We find a peak in the goodness of fit at 11 years for the moving average. The fit between the two misery indices holds when using different techniques to measure the literary misery index, and this fit is significantly better than other possible correlations with different emotion indices. To check the robustness of the results, we also analysed books written in German language and obtained very similar correlations with the German economic misery index. The results suggest that millions of books published every year average the authors' shared economic experiences over the past decade.

  4. Cordon Pricing Considering Air Pollutants Emission

    Directory of Open Access Journals (Sweden)

    Shahriar Afandizadeh

    2016-04-01

    Full Text Available This paper considers the issue of air pollutants emission for the optimal and sustainable determination of cordon location, toll level, and price of park and ride (P&R. Although air pollutants emission decreases within the cordon by the implementation of cordon pricing scheme, it may increase outside the cordon and the whole network. Hence, air pollutants emission may only transfer from inside of the cordon to its outside. Therefore, in this paper, a multi-objective bi-level optimization model is developed. A solution algorithm is also presented based on the second version of strength Pareto evolutionary algorithm (SPEA2. The results reveal that this multi-objective model can be a useful tool for the sustainable and optimal design of the cordon and P&R scheme. In addition, cordon pricing is a multi-objective problem. Therefore, it is necessary to consider air pollutants emission. By choosing another non-dominated result in the solution space, air pollutants emission outside the cordon and the whole network can be reduced without a significant reduction in social welfare.

  5. Induced vaginal birth after previous caesarean section

    Directory of Open Access Journals (Sweden)

    Akylbek Tussupkaliyev

    2016-11-01

    Full Text Available Introduction The rate of operative birth by Caesarean section is constantly rising. In Kazakhstan, it reaches 27 per cent. Research data confirm that the percentage of successful vaginal births after previous Caesarean section is 50–70 per cent. How safe the induction of vaginal birth after Caesarean (VBAC remains unclear. Methodology The studied techniques of labour induction were amniotomy of the foetal bladder with the vulsellum ramus, intravaginal administration of E1 prostaglandin (Misoprostol, and intravenous infusion of Oxytocin-Richter. The assessment of rediness of parturient canals was conducted by Bishop’s score; the labour course was assessed by a partogram. The effectiveness of labour induction techniques was assessed by the number of administered doses, the time of onset of regular labour, the course of labour and the postpartum period and the presence of complications, and the course of the early neonatal period, which implied the assessment of the child’s condition, described in the newborn development record. The foetus was assessed by medical ultrasound and antenatal and intranatal cardiotocography (CTG. Obtained results were analysed with SAS statistical processing software. Results The overall percentage of successful births with intravaginal administration of Misoprostol was 93 per cent (83 of cases. This percentage was higher than in the amniotomy group (relative risk (RR 11.7 and was similar to the oxytocin group (RR 0.83. Amniotomy was effective in 54 per cent (39 of cases, when it induced regular labour. Intravenous oxytocin infusion was effective in 94 per cent (89 of cases. This percentage was higher than that with amniotomy (RR 12.5. Conclusions The success of vaginal delivery after previous Caesarean section can be achieved in almost 70 per cent of cases. At that, labour induction does not decrease this indicator and remains within population boundaries.

  6. Secondary recurrent miscarriage is associated with previous male birth.

    LENUS (Irish Health Repository)

    Ooi, Poh Veh

    2011-01-01

    Secondary recurrent miscarriage (RM) is defined as three or more consecutive pregnancy losses after delivery of a viable infant. Previous reports suggest that a firstborn male child is associated with less favourable subsequent reproductive potential, possibly due to maternal immunisation against male-specific minor histocompatibility antigens. In a retrospective cohort study of 85 cases of secondary RM we aimed to determine if secondary RM was associated with (i) gender of previous child, maternal age, or duration of miscarriage history, and (ii) increased risk of pregnancy complications. Fifty-three women (62.0%; 53\\/85) gave birth to a male child prior to RM compared to 32 (38.0%; 32\\/85) who gave birth to a female child (p=0.002). The majority (91.7%; 78\\/85) had uncomplicated, term deliveries and normal birth weight neonates, with one quarter of the women previously delivered by Caesarean section. All had routine RM investigations and 19.0% (16\\/85) had an abnormal result. Fifty-seven women conceived again and 33.3% (19\\/57) miscarried, but there was no significant difference in failure rates between those with a previous male or female child (13\\/32 vs. 6\\/25, p=0.2). When patients with abnormal results were excluded, or when women with only one previous child were considered, there was still no difference in these rates. A previous male birth may be associated with an increased risk of secondary RM but numbers preclude concluding whether this increases recurrence risk. The suggested association with previous male birth provides a basis for further investigations at a molecular level.

  7. Secondary recurrent miscarriage is associated with previous male birth.

    LENUS (Irish Health Repository)

    Ooi, Poh Veh

    2012-01-31

    Secondary recurrent miscarriage (RM) is defined as three or more consecutive pregnancy losses after delivery of a viable infant. Previous reports suggest that a firstborn male child is associated with less favourable subsequent reproductive potential, possibly due to maternal immunisation against male-specific minor histocompatibility antigens. In a retrospective cohort study of 85 cases of secondary RM we aimed to determine if secondary RM was associated with (i) gender of previous child, maternal age, or duration of miscarriage history, and (ii) increased risk of pregnancy complications. Fifty-three women (62.0%; 53\\/85) gave birth to a male child prior to RM compared to 32 (38.0%; 32\\/85) who gave birth to a female child (p=0.002). The majority (91.7%; 78\\/85) had uncomplicated, term deliveries and normal birth weight neonates, with one quarter of the women previously delivered by Caesarean section. All had routine RM investigations and 19.0% (16\\/85) had an abnormal result. Fifty-seven women conceived again and 33.3% (19\\/57) miscarried, but there was no significant difference in failure rates between those with a previous male or female child (13\\/32 vs. 6\\/25, p=0.2). When patients with abnormal results were excluded, or when women with only one previous child were considered, there was still no difference in these rates. A previous male birth may be associated with an increased risk of secondary RM but numbers preclude concluding whether this increases recurrence risk. The suggested association with previous male birth provides a basis for further investigations at a molecular level.

  8. Previous experiences shape adaptive mate preferences

    NARCIS (Netherlands)

    Fawcett, Tim W.; Bleay, Colin

    2009-01-01

    Existing models of mate choice assume that individuals have perfect knowledge of their own ability to attract a mate and can adjust their preferences accordingly. However, real animals will typically be uncertain of their own attractiveness. A potentially useful source of information on this is the

  9. Sources of the Radio Background Considered

    Energy Technology Data Exchange (ETDEWEB)

    Singal, J.; /KIPAC, Menlo Park /Stanford U.; Stawarz, L.; /KIPAC, Menlo Park /Stanford U. /Jagiellonian U., Astron. Observ.; Lawrence, A.; /Edinburgh U., Inst. Astron. /KIPAC, Menlo Park /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

    2011-08-22

    We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

  10. Modelling of a steam reformer for fuel cell CHP systems considering intra- and extra-particulate transport phenomena; Modellierung eines Dampfreformers fuer stationaere Brennstoffzellen unter Beruecksichtigung von intra- und extrapartikulaeren Transportphaenomene

    Energy Technology Data Exchange (ETDEWEB)

    Nitzsche, J. [DBI-Gastechnologisches Institut, Freiberg (Germany)

    2009-07-01

    The modelling of methane steam-reforming fixed bed reactors requires detailed knowledge of limiting heat and mass transfer processes at the catalyst particle. Their influence is checked by a single particle model and the results are used to create an exact two-dimensional model of a reformer tube. This model allows for the implementation of an intensive significance analysis, which gives a better understanding of the process and provides for proper dimensioning of steam reformers. (orig.)

  11. What should be considered if you decide to build your own mathematical model for predicting the development of bacterial resistance? Recommendations based on a systematic review of the literature.

    Science.gov (United States)

    Arepeva, Maria; Kolbin, Alexey; Kurylev, Alexey; Balykina, Julia; Sidorenko, Sergey

    2015-01-01

    Acquired bacterial resistance is one of the causes of mortality and morbidity from infectious diseases. Mathematical modeling allows us to predict the spread of resistance and to some extent to control its dynamics. The purpose of this review was to examine existing mathematical models in order to understand the pros and cons of currently used approaches and to build our own model. During the analysis, seven articles on mathematical approaches to studying resistance that satisfied the inclusion/exclusion criteria were selected. All models were classified according to the approach used to study resistance in the presence of an antibiotic and were analyzed in terms of our research. Some models require modifications due to the specifics of the research. The plan for further work on model building is as follows: modify some models, according to our research, check all obtained models against our data, and select the optimal model or models with the best quality of prediction. After that we would be able to build a model for the development of resistance using the obtained results.

  12. Executive Function in Previously Institutionalized Children.

    Science.gov (United States)

    Merz, Emily C; Harlé, Katia M; Noble, Kimberly G; McCall, Robert B

    2016-06-01

    In studies of children adopted from institutions, being raised in an institution has been associated consistently with an increased risk of persistent cognitive, academic, and social-emotional problems. These findings raise questions about the neurocognitive mechanisms that contribute to these negative outcomes. Theory and models based on studies of animals indicate that development of the prefrontal cortex (PFC) and executive function (EF) may be particularly susceptible to environmental influences during early childhood. In this article, we review recent studies of postinstitutionalized children that examined EF components such as inhibitory control, working memory, shifting, and planning. We then describe emerging research on the structure and function of the PFC. Converging evidence suggests both EF difficulties and alterations in development of the PFC following early institutionalization. We conclude by discussing possible explanations for these findings and implications for prevention and intervention, and by offering suggestions for ongoing research.

  13. Considering people living with dementia when designing interfaces

    OpenAIRE

    Ancient, Claire; Good, Alice

    2014-01-01

    Dementia is an escalating problem which is estimated to affect 35.6 million people worldwide. In an environment which is becoming increasingly dependent on technology, the interaction needs of people living with dementia is being ignored by interface designers. This paper aims to highlight the factors which should be considered when designing interfaces to be "dementia-friendly". The article draws on the limited previous research to suggest that interfaces need to consider two main factors: p...

  14. Nicotine Elicits Methamphetamine-Seeking in Rats Previously Administered Nicotine

    OpenAIRE

    Neugebauer, N. M.; Harrod, S. B.; Bardo, M. T.

    2009-01-01

    Research has indicated a high correlation between psychostimulant use and tobacco cigarette smoking in human substance abusers. The objective of the current study was to examine the effects of acute and repeated nicotine administration on responding for intravenous methamphetamine (0.03 mg/kg/infusion) in a rodent model of self-administration, as well as the potential of nicotine to induce reinstatement of previously extinguished drug-taking behavior in male Sprague-Dawley rats. In addition, ...

  15. Rates of induced abortion in Denmark according to age, previous births and previous abortions

    Directory of Open Access Journals (Sweden)

    Marie-Louise H. Hansen

    2009-11-01

    Full Text Available Background: Whereas the effects of various socio-demographic determinants on a woman's risk of having an abortion are relatively well-documented, less attention has been given to the effect of previous abortions and births. Objective: To study the effect of previous abortions and births on Danish women's risk of an abortion, in addition to a number of demographic and personal characteristics. Data and methods: From the Fertility of Women and Couples Dataset we obtained data on the number of live births and induced abortions by year (1981-2001, age (16-39, county of residence and marital status. Logistic regression analysis was used to estimate the influence of the explanatory variables on the probability of having an abortion in a relevant year. Main findings and conclusion: A woman's risk of having an abortion increases with the number of previous births and previous abortions. Some interactions were was found in the way a woman's risk of abortion varies with calendar year, age and parity. The risk of an abortion for women with no children decreases while the risk of an abortion for women with children increases over time. Furthermore, the risk of an abortion decreases with age, but relatively more so for women with children compared to childless women. Trends for teenagers are discussed in a separate section.

  16. An Adaptive Neuro-Fuzzy Inference System for Sea Level Prediction Considering Tide-Generating Forces and Oceanic Thermal Expansion

    Directory of Open Access Journals (Sweden)

    Li-Ching Lin Hsien-Kuo Chang

    2008-01-01

    Full Text Available The paper presents an adaptive neuro fuzzy inference system for predicting sea level considering tide-generating forces and oceanic thermal expansion assuming a model of sea level dependence on sea surface temperature. The proposed model named TGFT-FN (Tide-Generating Forces considering sea surface Temperature and Fuzzy Neuro-network system is applied to predict tides at five tide gauge sites located in Taiwan and has the root mean square of error of about 7.3 - 15.0 cm. The capability of TGFT-FN model is superior in sea level prediction than the previous TGF-NN model developed by Chang and Lin (2006 that considers the tide-generating forces only. The TGFT-FN model is employed to train and predict the sea level of Hua-Lien station, and is also appropriate for the same prediction at the tide gauge sites next to Hua-Lien station.

  17. The forgotten artist: Why to consider intentions and interaction in a model of aesthetic experience. Comment on "Move me, astonish me... delight my eyes and brain: The Vienna Integrated Model of top-down and bottom-up processes in Art Perception (VIMAP) and corresponding affective, evaluative, and neurophysiological correlates" by Matthew Pelowski et al.

    Science.gov (United States)

    Brattico, Elvira; Brattico, Pauli; Vuust, Peter

    2017-07-01

    In their target article published in this journal issue, Pelowski et al. [1] address the question of how humans experience, and respond to, visual art. They propose a multi-layered model of the representations and processes involved in assessing visual art objects that, furthermore, involves both bottom-up and top-down elements. Their model provides predictions for seven different outcomes of human aesthetic experience, based on few distinct features (schema congruence, self-relevance, and coping necessity), and connects the underlying processing stages to ;specific correlates of the brain; (a similar attempt was previously done for music by [2-4]). In doing this, the model aims to account for the (often profound) experience of an individual viewer in front of an art object.

  18. New study reveals twice as many asteroids as previously believed

    Science.gov (United States)

    2002-05-01

    The ISO satellite Credits: ESA ISO An artist's impression of the ISO spacecraft. The ISO Deep Asteroid Search indicates that there are between 1.1 million and 1.9 million 'space rocks' larger than 1 kilometre in diameter in the so-called 'main asteroid belt', about twice as many as previously believed. However, astronomers think it is premature to revise current assessments of the risk of the Earth being hit by an asteroid. Despite being in our own Solar System, asteroids can be more difficult to study than very distant galaxies. With sizes of up to one thousand kilometres in diameter, the brightness of these rocky objects may vary considerably in just a few minutes. They move very quickly with respect to the stars - they have been dubbed 'vermin of the sky' because they often appear as trails on long exposure images. This elusiveness explains why their actual number and size distribution remains uncertain. Most of the almost 40,000 asteroids catalogued so far (1) orbit the Sun forming the 'main asteroid belt', between Mars and Jupiter, too far to pose any threat to Earth. However, space-watchers do keep a closer eye on another category of asteroids, the 'Near Earth Asteroids' or 'NEAs', which are those whose orbits cross, or are likely to cross, that of our planet. The ISO Deep Asteroid Search (IDAS), the first systematic search for these objects performed in infrared light, focused on main belt asteroids. Because it is impossible to simply point the telescope at the whole main belt and count, astronomers choose selected regions of the belt and then use a theoretical model to extrapolate the data to the whole belt. Edward Tedesco (TerraSystems, Inc., New Hampshire, United States) and François-Xavier Desert (Observatoire de Grenoble, France) observed their main belt selected areas in 1996 and 1997 with ESA's ISO. They found that in the middle region of the belt the density of asteroids was 160 asteroids larger than 1 kilometre per square degree - an area of the

  19. Warranty claim analysis considering human factors

    International Nuclear Information System (INIS)

    Wu Shaomin

    2011-01-01

    Warranty claims are not always due to product failures. They can also be caused by two types of human factors. On the one hand, consumers might claim warranty due to misuse and/or failures caused by various human factors. Such claims might account for more than 10% of all reported claims. On the other hand, consumers might not be bothered to claim warranty for failed items that are still under warranty, or they may claim warranty after they have experienced several intermittent failures. These two types of human factors can affect warranty claim costs. However, research in this area has received rather little attention. In this paper, we propose three models to estimate the expected warranty cost when the two types of human factors are included. We consider two types of failures: intermittent and fatal failures, which might result in different claim patterns. Consumers might report claims after a fatal failure has occurred, and upon intermittent failures they might report claims after a number of failures have occurred. Numerical examples are given to validate the results derived.

  20. Dose assessment considering evolution of the biosphere

    International Nuclear Information System (INIS)

    Karlsson, Sara; Bergstroem, Ulla

    2002-01-01

    Swedish Nuclear Fuel and Waste Management AB (SKB) is presently updating the safety assessment for SFR (Final repository for radioactive operational waste) in Sweden. The bio-spheric part of the analysis is performed by Studsvik Eco and Safety AB. According to the regulations the safety of the repository has to be accounted for different possible courses of the development of the biosphere. A number of studies have been carried out during the past years to investigate and document the biosphere in the area surrounding the repository. Modelling of shore-level displacement by land uplift, coastal water exchange and sedimentation have provided data for prediction of the evolution of the area. The prediction is done without considering a future change in climatic conditions. The results from this study show that accumulation of radionuclides in sediments is an important process to simulate when performing dose assessments covering biosphere evolution. The dose calculated for the first years of the period with agricultural use of the contaminated sediments may be severely underestimated in a scenario with large accumulation in coastal and lake stages. (LN)

  1. Elaboration of a concept for modelling creep damage and rupture processes in structural components made of heat-resistant CrMoV steels, considering multi-axial stress regimes and formation of pores. Final report

    International Nuclear Information System (INIS)

    Gaudig, W.

    1997-01-01

    The research project was intended to study and elaborate models describing the creep performance of heat-resistant CrMoV steels over the entire creep regime, including the damage processes (tertiary creep). The mathematical description of the creep performance and damages induced is required for the calculation of deformation, stresses and damage affecting structural components over their service life, so that information can be derived about their remanent life. The objective was achieved by describing the interaction between deformation and damage due to cavitation. A model was elaborated that uses an anisotropic cavitation parameter (tensor). The model was tested with and adapted to the material X 20 CrMoV 12 1 and its behaviour at 550 C using data obtained through uni-axial creep tests at constant loading. The modified model was used for recalculation of a long-term experiment at MPA Stuttgart, performed at 550 C with a pipe elbow made of the charge-identical material X 20 XrMoV 12 1, applying the ABAQUS FE program. Mechanical total strains calculated for selected nodes are in good agreement with corresponding measured data. (orig./CB) [de

  2. Materials model for describing the austenite-martensite phase transformation considering transformation-induced plasticity; Ein Materialmodell zur Beschreibung der Austenit-Martensit Phasentransformation unter Beruecksichtigung der transformationsinduzierten Plastizitaet

    Energy Technology Data Exchange (ETDEWEB)

    Oberste-Brandenburg, C.

    1999-06-01

    In this thesis, a model to describe the austenite martensite transformation was developed. The transformation induced plasticity (TRIP) was taken into consideration. The model can be used to design complex structures. A local examination of the energy and entropy balance at the phase boundary serves as the starting point for the identification of the thermodynamical driving force and the thermodynamic flow. For both, a tensorial description is necessary for a general nonhydrostatically stressed solid. In the second part, a material law for the description of TRIP-Steels was developed based on the values derived in the first part. The different mechanical behavior of the phases, especially the differing yield stresses, was taken into account. The model developed was implemented into the finite element program MARC. Simulations of the material and the structural behavior were performed. The experimentally observed strong dependence of the transformation kinetics on the yield stress of the austenite and the dependence of the orientation of the martensite inclusion on the stress state could be verified. (orig.) [German] Im Rahmen dieser Arbeit wurde ein Materialmodell zur Beschreibung der Austenit-Martensit Phasenumwandlung unter Beruecksichtigung der transformationsinduzierten Plastizitaet (TRIP) entwickelt. Das Modell ist zur Berechnung ausgedehnter Strukturen einsetzbar. Eine lokale Betrachtung der Energie- und Entropiebilanz an der Phasengrenze bildet den Ausgangspunkt zur Identifikation der thermodynamischen Kraft und des thermodynamischen Flusses bei Beschreibung der Transformationskinetik. Fuer beide Groessen muss fuer den allgemein nichthydrostatischen Spannungszustand eine tensorielle Beschreibung verwendet werden. Im zweiten Teil der Arbeit bilden diese Groessen die Basis zur Entwicklung eines Stoffgesetzes zur Beschreibung des TRIP-Phaenomens. Es wird das unterschiedliche mechanische Verhalten der Phasen, insbesondere die stark unterschiedlichen

  3. Optimal temperature for malaria transmission is dramaticallylower than previously predicted

    Science.gov (United States)

    Mordecai, Eerin A.; Paaijmans, Krijin P.; Johnson, Leah R.; Balzer, Christian; Ben-Horin, Tal; de Moor, Emily; McNally, Amy; Pawar, Samraat; Ryan, Sadie J.; Smith, Thomas C.; Lafferty, Kevin D.

    2013-01-01

    The ecology of mosquito vectors and malaria parasites affect the incidence, seasonal transmission and geographical range of malaria. Most malaria models to date assume constant or linear responses of mosquito and parasite life-history traits to temperature, predicting optimal transmission at 31 °C. These models are at odds with field observations of transmission dating back nearly a century. We build a model with more realistic ecological assumptions about the thermal physiology of insects. Our model, which includes empirically derived nonlinear thermal responses, predicts optimal malaria transmission at 25 °C (6 °C lower than previous models). Moreover, the model predicts that transmission decreases dramatically at temperatures > 28 °C, altering predictions about how climate change will affect malaria. A large data set on malaria transmission risk in Africa validates both the 25 °C optimum and the decline above 28 °C. Using these more accurate nonlinear thermal-response models will aid in understanding the effects of current and future temperature regimes on disease transmission.

  4. Evaluation of Different Methods for Considering Bar-Concrete ...

    African Journals Online (AJOL)

    theory, but the perfect bond assumption has been removed. The precision of the proposed method in considering the real nonlinear behavior of reinforced concrete frames has been compared to the precision of two other suggested methods for considering bond-slip effect in layer model. Among the capabilities of this ...

  5. Iowa Gambling Task: There is more to consider than long-term outcome.Using a linear equation model to disentangle the impact of outcome and frequency of gains and losses.

    Directory of Open Access Journals (Sweden)

    Annette eHorstmann

    2012-05-01

    Full Text Available The Iowa Gambling Task (IGT has been widely used to assess differences in decision-making under uncertainty. Recently, several studies have shown that healthy subjects do not meet the basic predictions of the task (i.e. prefer options with positive long-term outcome, hence questioning its basic assumptions. Since choice options are characterized by gain and net loss frequency in addition to long-term outcome, we hypothesized that a combination of features rather than a single feature would influence participants’ choices. Offering an alternative way of modeling IGT data, we propose to use a system of linear equations to estimate weights that quantify the influence of each individual feature on decision-making in the IGT. With our proposed model it is possible to disentangle and quantify the impact of each of these features.Results from 119 healthy young subjects suggest that choice behavior is predominantly influenced by gain and loss frequency. Subjects preferred choices associated with high frequency gains to those with low frequency gains, regardless of long-term outcome. However, among options with low frequency gains, subjects learned to distinguish between choices that led to advantageous and disadvantageous long-term consequences. This is reflected in the relationship between the weights for gain frequency (highest, loss frequency (intermediate and long-term outcome (lowest. Further, cluster analysis of estimated feature weights revealed subgroups of participants with distinct weight patterns and associated advantageous decision behavior. However, subjects in general do not learn to solely base their preference for particular decks on expected long-term outcome. Consequently, long-term outcome alone is not able to drive choice behavior on the IGT. In sum, our model facilitates a more focused conclusion about the factors guiding decision-making in the IGT. In addition, differences between clinical groups can be assessed for each factor

  6. Dynamic cellular manufacturing system design considering ...

    Indian Academy of Sciences (India)

    Kamal Deep

    tradeoff in a dynamic cellular manufacturing system is proposed in consideration with multiple part process route. This paper puts emphasize on the .... limited number of distinct paths considering resource capacity. The best routing is ..... all the other methods considered such as bond energy algorithm, direct clustering ...

  7. Efforts to promote vaginal delivery after a previous cesarean section.

    Science.gov (United States)

    Hamai, Yoko; Imanishi, Yukio

    2012-01-01

    The aim of this study was to examine the results of vaginal delivery in patients with a past history of cesarean section. The type of delivery, interventions during delivery, and the prognoses of the mothers and babies were examined in 145 women with a history of cesarean section over the 10-year period from January 2000 to December 2009. A scheduled cesarean section was performed in 27 cases. Vaginal delivery was recommended in 118 cases and the success rate was 94.9% (112/118). Uterine rupture was observed in one patient who experienced a natural rupture at home and whose previous cesarean section was an inverse T incision. No cases required a blood transfusion or hysterectomy. The prognoses of both mothers and babies were good and the vaginal delivery success rate was 94.9%. Uterine rupture was observed in one case. Vaginal delivery with previous cesarean section should be considered in cases with expectation and informed consent. © 2011 The Authors. Journal of Obstetrics and Gynaecology Research © 2011 Japan Society of Obstetrics and Gynecology.

  8. Path Forward to Space Solar Power using the O'Neill - Glaser Model Modified for Climate Change Demand and Considering the Increasing Risk of Human Self-Extinction if Confined to Earth

    Science.gov (United States)

    Curreri, Peter A.; Nall, Mark

    2013-01-01

    The cost of energy is humanity's economic exchange rate with the universe. Space solar power is the first great step that our technological species has to utilize the energy of its star. The classic Peter Glaser Solar Power Satellite, SPS, and later designs collect a large area of solar energy in space and beam it back to Earth for use in the electric grid, but even with optimistic launch costs and technology innovation a clear economic path is not evident using Earth launch of SPS. O Neill in 1969 solved the transportation costs problem by a model that uses lunar and asteroid materials to build SPS and locates the labor force permanently in space (O Neill free space habitats). This solution closes the economics and predicts large profits after 17-35 years. However the costs of time have up to now prevented this solution. We discuss a strategy to move forward in SPS with the motivations to stop global warming and prevent human selfextinction. There are near term steps that can be taken that place us on this path forward. First, we must reevaluate the technologies for the classic model and update the parameters to current technology. As technological capability continues to increase exponentially, we need to understand when the monetary potential energy hills are small as the technology gets larger. But the chance for self-extinction, if humanity remains in a single vulnerable habitat, also increased exponentially with time. The path forward is to identify investment points while assessing the risks of non-action.

  9. HEART TRANSPLANTATION IN PATIENTS WITH PREVIOUS OPEN HEART SURGERY

    Directory of Open Access Journals (Sweden)

    R. Sh. Saitgareev

    2016-01-01

    Full Text Available Heart Transplantation (HTx to date remains the most effective and radical method of treatment of patients with end-stage heart failure. The defi cit of donor hearts is forcing to resort increasingly to the use of different longterm mechanical circulatory support systems, including as a «bridge» to the follow-up HTx. According to the ISHLT Registry the number of recipients underwent cardiopulmonary bypass surgery increased from 40% in the period from 2004 to 2008 to 49.6% for the period from 2009 to 2015. HTx performed in repeated patients, on the one hand, involves considerable technical diffi culties and high risks; on the other hand, there is often no alternative medical intervention to HTx, and if not dictated by absolute contradictions the denial of the surgery is equivalent to 100% mortality. This review summarizes the results of a number of published studies aimed at understanding the immediate and late results of HTx in patients, previously underwent open heart surgery. The effect of resternotomy during HTx and that of the specifi c features associated with its implementation in recipients previously operated on open heart, and its effects on the immediate and long-term survival were considered in this review. Results of studies analyzing the risk factors for perioperative complications in repeated recipients were also demonstrated. Separately, HTx risks after implantation of prolonged mechanical circulatory support systems were examined. The literature does not allow to clearly defi ning the impact factor of earlier performed open heart surgery on the course of perioperative period and on the prognosis of survival in recipients who underwent HTx. On the other hand, subject to the regular fl ow of HTx and the perioperative period the risks in this clinical situation are justifi ed as a long-term prognosis of recipients previously conducted open heart surgery and are comparable to those of patients who underwent primary HTx. Studies

  10. Influence of Previous Knowledge, Language Skills and Domain-specific Interest on Observation Competency

    Science.gov (United States)

    Kohlhauf, Lucia; Rutke, Ulrike; Neuhaus, Birgit

    2011-10-01

    Many epoch-making biological discoveries (e.g. Darwinian Theory) were based upon observations. Nevertheless, observation is often regarded as `just looking' rather than a basic scientific skill. As observation is one of the main research methods in biological sciences, it must be considered as an independent research method and systematic practice of this method is necessary. Because observation skills form the basis of further scientific methods (e.g. experiments or comparisons) and children from the age of 4 years are able to independently generate questions and hypotheses, it seems possible to foster observation competency at a preschool level. To be able to provide development-adequate individual fostering of this competency, it is first necessary to assess each child's competency. Therefore, drawing on the recent literature, we developed in this study a competency model that was empirically evaluated within learners ( N = 110) from different age groups, from kindergarten to university. In addition, we collected data on language skills, domain-specific interest and previous knowledge to analyse coherence between these skills and observation competency. The study showed as expected that previous knowledge had a high impact on observation competency, whereas the influence of domain-specific interest was nonexistent. Language skills were shown to have a weak influence. By utilising the empirically validated model consisting of three dimensions (`Describing', `Scientific reasoning' and `Interpreting') and three skill levels, it was possible to assess each child's competency level and to develop and evaluate guided play activities to individually foster a child's observation competency.

  11. Typing DNA profiles from previously enhanced fingerprints using direct PCR.

    Science.gov (United States)

    Templeton, Jennifer E L; Taylor, Duncan; Handt, Oliva; Linacre, Adrian

    2017-07-01

    Fingermarks are a source of human identification both through the ridge patterns and DNA profiling. Typing nuclear STR DNA markers from previously enhanced fingermarks provides an alternative method of utilising the limited fingermark deposit that can be left behind during a criminal act. Dusting with fingerprint powders is a standard method used in classical fingermark enhancement and can affect DNA data. The ability to generate informative DNA profiles from powdered fingerprints using direct PCR swabs was investigated. Direct PCR was used as the opportunity to generate usable DNA profiles after performing any of the standard DNA extraction processes is minimal. Omitting the extraction step will, for many samples, be the key to success if there is limited sample DNA. DNA profiles were generated by direct PCR from 160 fingermarks after treatment with one of the following dactyloscopic fingerprint powders: white hadonite; silver aluminium; HiFi Volcano silk black; or black magnetic fingerprint powder. This was achieved by a combination of an optimised double-swabbing technique and swab media, omission of the extraction step to minimise loss of critical low-template DNA, and additional AmpliTaq Gold ® DNA polymerase to boost the PCR. Ninety eight out of 160 samples (61%) were considered 'up-loadable' to the Australian National Criminal Investigation DNA Database (NCIDD). The method described required a minimum of working steps, equipment and reagents, and was completed within 4h. Direct PCR allows the generation of DNA profiles from enhanced prints without the need to increase PCR cycle numbers beyond manufacturer's recommendations. Particular emphasis was placed on preventing contamination by applying strict protocols and avoiding the use of previously used fingerprint brushes. Based on this extensive survey, the data provided indicate minimal effects of any of these four powders on the chance of obtaining DNA profiles from enhanced fingermarks. Copyright © 2017

  12. Distributed energy resources scheduling considering real-time resources forecast

    DEFF Research Database (Denmark)

    Silva, M.; Sousa, T.; Ramos, S.

    2014-01-01

    grids and considering day-ahead, hour-ahead and realtime time horizons. This method considers that energy resources are managed by a VPP which establishes contracts with their owners. The full AC power flow calculation included in the model takes into account network constraints. In this paper......, distribution function errors are used to simulate variations between time horizons, and to measure the performance of the proposed methodology. A 33-bus distribution network with large number of distributed resources is used....

  13. The Challenge of Film Considered as Historical Research

    Directory of Open Access Journals (Sweden)

    Olaf Berg

    2011-04-01

    Full Text Available The article focuses on the use of film as a medium of historical research. It discusses the film "Shoah," directed by Claude Lanzmann, which is considered as a model for filmic history. It also looks into Robert Rosenstone's claim that people may consider filmmakers as historians and that people should derive theory from practice through analyzing how the past has been portrayed in films.

  14. Optimization of hydraulic machinery by exploiting previous successful designs

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, S A; Giannakoglou, K C [National Technical University of Athens, Parallel CFD and Optimization Unit, PO Box 64069, Athens 15710 (Greece); Weissenberger, S; Grafenberger, P, E-mail: stelios.Kyriacou@gmail.co [Andritz HYDRO, RD, Lunzerstrasse 78, 4031 Linz (Austria)

    2010-08-15

    A design-optimization method for hydraulic machinery is proposed. Optimal designs are obtained using the appropriate CFD evaluation software driven by an evolutionary algorithm which is also assisted by artificial neural networks used as surrogate evaluation models or metamodels. As shown in a previous IAHR paper by the same authors, such an optimization method substantially reduces the CPU cost, since the metamodels can discard numerous non-promising candidate solutions generated during the evolution, at almost negligible CPU cost, without evaluating them by means of the costly CFD tool. The present paper extends the optimization method of the previous paper by making it capable to accommodate and exploit pieces of useful information archived during previous relevant successful designs. So, instead of parameterizing the geometry of the hydraulic machine components, which inevitably leads to many design variables, enough to slow down the design procedure, in the proposed method all new designs are expressed as weighted combinations of the archived ones. The archived designs act as the design space bases. The role of the optimization algorithms is to find the set (or sets, for more than one objectives, where the Pareto front of non-dominated solutions is sought) of weight values, corresponding to the hydraulic machine configuration(s) with optimal performance. Since the number of weights is much less that the number of design variables of the conventional shape parameterization, the design space dimension reduces and the CPU cost of the metamodel-assisted evolutionary algorithm is much lower. The design of a Francis runner is used to demonstrate the capabilities of the proposed method.

  15. Reliability evaluation of microgrid considering incentive-based demand response

    Science.gov (United States)

    Huang, Ting-Cheng; Zhang, Yong-Jun

    2017-07-01

    Incentive-based demand response (IBDR) can guide customers to adjust their behaviour of electricity and curtail load actively. Meanwhile, distributed generation (DG) and energy storage system (ESS) can provide time for the implementation of IBDR. The paper focus on the reliability evaluation of microgrid considering IBDR. Firstly, the mechanism of IBDR and its impact on power supply reliability are analysed. Secondly, the IBDR dispatch model considering customer’s comprehensive assessment and the customer response model are developed. Thirdly, the reliability evaluation method considering IBDR based on Monte Carlo simulation is proposed. Finally, the validity of the above models and method is studied through numerical tests on modified RBTS Bus6 test system. Simulation results demonstrated that IBDR can improve the reliability of microgrid.

  16. Access, Consider, Teach: ACT in Your Classroom

    Science.gov (United States)

    Stanford, Pokey; Reeves, Stacy

    2007-01-01

    University teachers who are teacher educators cannot connect to "The Millennial Generation" of today's preservice learners by using chalk and dull outdated textbooks. When university professionals access the technology available, consider the curriculum, and teach with technology (ACT) undergraduate teacher candidates acquire the vision of…

  17. The Musical Mind Considered: A New Frontier.

    Science.gov (United States)

    Vincent, Marilyn C.; Merrion, Margaret

    1990-01-01

    Examines how new theories about the mind and brain affect music education. Specifically considers the nature of the musical mind and the nature of music. Discusses the work of Robert Ornstein, D. Alan Allport, Howard Gardner, and David Loye. Recommends that music educators, at all levels, incorporate these perspectives into their teaching. (KM)

  18. 40 CFR 227.21 - Uses considered.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Uses considered. 227.21 Section 227.21 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE... living marine resources; (k) Actual or anticipated exploitation of non-living resources, including...

  19. 40 CFR 227.18 - Factors considered.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Factors considered. 227.18 Section 227.18 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR... in the material of any constituents which might significantly affect living marine resources of...

  20. Tempo curves considered harmful (part 1)

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1991-01-01

    A column (the first of a series of three) constitutes an abridged and adapted version of Tempo curves considered harmful . Two friends, an amateur mathematician (M) and a would-be psychologist (P), invited a retired pianist to do some experiments with their new sequencer program. As musical material

  1. ENERGY GENERATION EXPANSION PLANNING MODEL CONSIDERING EMISSIONS CONSTRAINTS

    Directory of Open Access Journals (Sweden)

    DIEGO ADOLFO MEJIA GIRALDO

    2010-01-01

    Full Text Available El problema de expansión de la generación consiste en determinar el tipo de tecnología, dimensionamiento, ubicación y momento en el cual nuevas plantas de generación deben ser integradas al sistema, en un horizonte de planeamiento dado, para satisfacer la demanda de energía pronosticada. En los últimos años, debido a un creciente interés en asuntos medioambientales, varias metodologías para resolver el problema de expansión de la generación han incluido algún tipo de política medioambiental, típicamente basada en restricciones de emisiones. Este artículo presenta un modelo lineal en una versión dinámica para resolver el problema de planeamiento de expansión de la generación. La principal diferencia entre el modelo propuesto y la mayoría de los trabajos presentados en la literatura especializada es la forma en que la política medioambiental ha sido contemplada. Tal política incluye: i impuestos sobre las emisiones de CO2, ii una reducción anual de emisiones en todo el sistema y iii el retiro gradual de plantas de generación ineficientes. El modelo propuesto ha sido aplicado al caso de expansión de los Estados Unidos para encontrar el portafolio de energía más rentable y sostenible en los próximos 20 años, considerando 11 regiones y 10 tipos diferentes de tecnología.

  2. Considering Bilingual Dictionaries Against a Corpus.

    African Journals Online (AJOL)

    A full description of the corpus is given in Johansson et al. (1978). We ..... rap's, for example, are at a disadvantage because the consider +ing-form pattern ...... to M rensid~n!d, c'est com pIe de; h~ has a un homme donI on faul wlf~ and family to - il a lenir com pIe un" femme el une famille • prendre en. conRideralion.

  3. Supplier Selection by Considering Cost and Reliability

    OpenAIRE

    K. -H. Yang

    2016-01-01

    Supplier selection problem is one of the important issues of supply chain problems. Two categories of methodologies include qualitative and quantitative approaches which can be applied to supplier selection problems. However, due to the complexities of the problem and lacking of reliable and quantitative data, qualitative approaches are more than quantitative approaches. This study considers operational cost and supplier's reliability factor and solves the problem by using a quantitative appr...

  4. Total Site Heat Integration Considering Pressure Drops

    Directory of Open Access Journals (Sweden)

    Kew Hong Chew

    2015-02-01

    Full Text Available Pressure drop is an important consideration in Total Site Heat Integration (TSHI. This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%.

  5. What to Consider for Animal Research

    Science.gov (United States)

    2016-10-27

    FROM: 59 MDW/SGVU SUBJECT: Professional Presentation Approval 14 NOV 2016 1. Your paper, entitled What to Consider for Animal Research presented at...for Animal Research 7 FUNDING RECEIVED FOR THIS STUDY? D YES [8I NO FUNDING SOURCE 8 DO YOU NEED FUNDING SUPPORT FOR PUBLICATION PURPOSES: 0 YES [81...a Pnmary/Corresponding Author Ann<.’kc C. Bush GS-14 59 MDW/ ST/SGVUS b c d e. f I CERTIFY ANY HUMAN OR ANIMAL RESEARCH RELATED STUDIES WERE

  6. Is Previous Respiratory Disease a Risk Factor for Lung Cancer?

    Science.gov (United States)

    Denholm, Rachel; Schüz, Joachim; Straif, Kurt; Stücker, Isabelle; Jöckel, Karl-Heinz; Brenner, Darren R.; De Matteis, Sara; Boffetta, Paolo; Guida, Florence; Brüske, Irene; Wichmann, Heinz-Erich; Landi, Maria Teresa; Caporaso, Neil; Siemiatycki, Jack; Ahrens, Wolfgang; Pohlabeln, Hermann; Zaridze, David; Field, John K.; McLaughlin, John; Demers, Paul; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Rudnai, Peter; Fabianova, Eleonora; Dumitru, Rodica Stanescu; Bencko, Vladimir; Foretova, Lenka; Janout, Vladimir; Kendzia, Benjamin; Peters, Susan; Behrens, Thomas; Vermeulen, Roel; Brüning, Thomas; Kromhout, Hans

    2014-01-01

    Rationale: Previous respiratory diseases have been associated with increased risk of lung cancer. Respiratory conditions often co-occur and few studies have investigated multiple conditions simultaneously. Objectives: Investigate lung cancer risk associated with chronic bronchitis, emphysema, tuberculosis, pneumonia, and asthma. Methods: The SYNERGY project pooled information on previous respiratory diseases from 12,739 case subjects and 14,945 control subjects from 7 case–control studies conducted in Europe and Canada. Multivariate logistic regression models were used to investigate the relationship between individual diseases adjusting for co-occurring conditions, and patterns of respiratory disease diagnoses and lung cancer. Analyses were stratified by sex, and adjusted for age, center, ever-employed in a high-risk occupation, education, smoking status, cigarette pack-years, and time since quitting smoking. Measurements and Main Results: Chronic bronchitis and emphysema were positively associated with lung cancer, after accounting for other respiratory diseases and smoking (e.g., in men: odds ratio [OR], 1.33; 95% confidence interval [CI], 1.20–1.48 and OR, 1.50; 95% CI, 1.21–1.87, respectively). A positive relationship was observed between lung cancer and pneumonia diagnosed 2 years or less before lung cancer (OR, 3.31; 95% CI, 2.33–4.70 for men), but not longer. Co-occurrence of chronic bronchitis and emphysema and/or pneumonia had a stronger positive association with lung cancer than chronic bronchitis “only.” Asthma had an inverse association with lung cancer, the association being stronger with an asthma diagnosis 5 years or more before lung cancer compared with shorter. Conclusions: Findings from this large international case–control consortium indicate that after accounting for co-occurring respiratory diseases, chronic bronchitis and emphysema continue to have a positive association with lung cancer. PMID:25054566

  7. 22 CFR 40.91 - Certain aliens previously removed.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Certain aliens previously removed. 40.91... IMMIGRANTS UNDER THE IMMIGRATION AND NATIONALITY ACT, AS AMENDED Aliens Previously Removed § 40.91 Certain aliens previously removed. (a) 5-year bar. An alien who has been found inadmissible, whether as a result...

  8. EURATOM. Considered from an economic perspective

    International Nuclear Information System (INIS)

    Balke, Siegfried

    2015-01-01

    The European Atomic Energy Community (EAG-EURATOM), which was organisationally established on 1st January 1958, is not to the same degree part of an economic discussion as the European Economic Community. The EAG has a strongly accentuated technical-scientific character and is often economically considered as appendix of major economic integration efforts within Europe. Still it would be wrong not to suspect economical effective components within the European Atomic Energy Community. The opposite is already recognisable as the EAG needs to integrate itself into a system of international organisations and institutions, which are already existent in the field of a friendly exploitation of nuclear power and which embrace a larger geographical field as the six - member-states of the EURATOM, the European Economic Community and the European Coal and Steel Community. One advantage of the treaty on establishing the European community is that it considers the Atomic Energy Community as an important but not independent branch from general economic activity. The organisational bracket for all three European Treaties of Integration will be the common Parliament and - what is to be expected, in its practical impact a -not to be underestimated- joint headquarters for all three institutions.

  9. Considering Maintenance Cost in Unit Commitment Problems

    Directory of Open Access Journals (Sweden)

    Hyeongon Park

    2017-11-01

    Full Text Available Electric power systems worldwide are receiving an increasing volume of wind power generation (WPG because of environmental concerns and cost declines associated with technological innovation. To manage the uncertainty of WPG, a system operator must commit sufficient conventional generators to provide an appropriate reserve. At times, frequent start and stop operations are applied to certain generators, which incurs maintenance costs associated with thermal-mechanical fatigue. In this paper, we suggest a comprehensive approach to unit commitment (UC that considers maintenance cost: the parameters of equivalent start (ES and equivalent base load hours (EBHs are adopted in the UC problem to determine optimal generation scheduling. A new formulation for the maintenance cost that can be readily combined with an existing mixed integer linear programming algorithm is presented. The effectiveness of the proposed UC method is verified through simulations based on an IEEE 118-bus test system. The simulation results show that considering maintenance cost in the UC problem effectively restricts frequent start and stop operation scheduling. Furthermore, the operating cost is reduced, the required reserve level is maintained, and the computational time is comparable with that of the conventional UC method.

  10. Serratia liquefaciens Infection of a Previously Excluded Popliteal Artery Aneurysm

    Directory of Open Access Journals (Sweden)

    A. Coelho

    Full Text Available : Introduction: Popliteal artery aneurysms (PAAs are rare in the general population, but they account for nearly 70% of peripheral arterial aneurysms. There are several possible surgical approaches including exclusion of the aneurysm and bypass grafting, or endoaneurysmorrhaphy and interposition of a prosthetic conduit. The outcomes following the first approach are favorable, but persistent blood flow in the aneurysm sac has been documented in up to one third of patients in the early post-operative setting. Complications from incompletely excluded aneurysms include aneurysm enlargement, local compression symptoms, and sac rupture. Notably infection of a previously excluded and bypassed PAA is rare. This is the third reported case of PAA infection after exclusion and bypass grafting and the first due to Serratia liquefaciens. Methods: Relevant medical data were collected from the hospital database. Results: This case report describes a 54 year old male patient, diagnosed with acute limb ischaemia due to a thrombosed PAA, submitted to emergency surgery with exclusion and venous bypass. A below the knee amputation was necessary 3 months later. Patient follow-up was lost until 7 years following surgical repair, when he was diagnosed with aneurysm sac infection with skin fistulisation. He had recently been diagnosed with alcoholic hepatic cirrhosis Child–Pugh Class B. The patient was successfully treated by aneurysm resection, soft tissue debridement and systemic antibiotics. Conclusion: PAA infection is a rare complication after exclusion and bypass procedures but should be considered in any patient with evidence of local or systemic infection. When a PAA infection is diagnosed, aneurysmectomy, local debridement, and intravenous antibiotic therapy are recommended. The “gold standard” method of PAA repair remains controversial. PAA excision or endoaneurysmorrhaphy avoids complications from incompletely excluded aneurysms, but is associated with

  11. Determining root correspondence between previously and newly detected objects

    Science.gov (United States)

    Paglieroni, David W.; Beer, N Reginald

    2014-06-17

    A system that applies attribute and topology based change detection to networks of objects that were detected on previous scans of a structure, roadway, or area of interest. The attributes capture properties or characteristics of the previously detected objects, such as location, time of detection, size, elongation, orientation, etc. The topology of the network of previously detected objects is maintained in a constellation database that stores attributes of previously detected objects and implicitly captures the geometrical structure of the network. A change detection system detects change by comparing the attributes and topology of new objects detected on the latest scan to the constellation database of previously detected objects.

  12. Oscillating heat pipe simulation considering dryout phenomena

    Science.gov (United States)

    Senjaya, Raffles; Inoue, Takayoshi

    2014-10-01

    In heat transport devices such as oscillating heat pipe (OHP), dryout phenomena is very important and avoided in order to give the optimum performance. However, from the previous studies (including our studies), the dryout phenomena in OHP and its mechanism are still unclear. In our studies of OHP (Senjaya and Inoue in Appl Thermal Eng 60:251-255, 2013; Int J Heat Mass Transfer 60:816-824, 2013; Int J Heat Mass Transfer 60:825-835, 2013), we introduced the importance and roles of liquid film in the operating principle of OHP. In our previous simulation, the thickness of liquid film was assumed to be uniform along a vapor plug. Then, dryout never occurred because there was the liquid transfer from the liquid film in the cooling section to that in the heating section. In this research, the liquid film is not treated uniformly but it is meshed similarly with the vapor plugs and liquid slugs. All governing equations are also solved in each control volume of liquid film. The simulation results show that dryout occurs in the simulation without bubble generation and growth. Dryout is started in the middle of vapor plug, because the liquid supply from the left and right liquid slugs cannot reach until the liquid film in the middle of vapor plug, and propagates to the left and right sides of a vapor plug. By inserting the bubble generation and growth phenomena, dryout does not occur because the wall of heating section is always wetted during the bubble growth and the thickness of liquid film is almost constant. The effects of meshing size of liquid film and wall temperature of heating section are also investigated. The results show that the smaller meshing size, the smaller liquid transfer rate and the faster of dryout propagation. In the OHP with higher wall temperature of heating section, dryout and its propagation also occur faster.

  13. Considering value of information when using CFD in design

    Energy Technology Data Exchange (ETDEWEB)

    Misra, John Satprim [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    This thesis presents an approach to find lower resolution CFD models that can accurately lead a designer to a correct decision at a lower computational cost. High-fidelity CFD models often contain too much information and come at a higher computational cost, limiting the designs a designer can test and how much optimization can be performed on the design. Lower model resolution is commonly used to reduce computational time. However there are no clear guidelines on how much model accuracy is required. Instead experience and intuition are used to select an appropriate lower resolution model. This thesis presents an alternative to this ad hoc method by considering the added value of the addition information provided by increasing accurate and more computationally expensive models.

  14. Identification of cutting force coefficients in machining process considering cutter vibration

    Science.gov (United States)

    Yao, Qi; Luo, Ming; Zhang, Dinghua; Wu, Baohai

    2018-03-01

    Among current cutting force models, cutting force coefficients still are the foundation of predicting calculation combined with consideration of geometry engagement variation, equipment characteristics, material properties and so on. Attached with unimpeachable significance, the traditional and some novel identification methods of cutting force coefficient are still faced with trouble, including repeated onerous work, over ideal measuring condition, variation of value due to material divergence, interference from measuring units. To utilize the large amount of data from real manufacturing section, enlarge data sources and enrich cutting data base for former prediction task, a novel identification method is proposed by considering stiffness properties of the cutter-holder-spindle system in this paper. According to previously proposed studies, the direct result of cutter vibration is the form of dynamic undeformed chip thickness. This fluctuation is considered in two stages of this investigation. Firstly, a cutting force model combined with cutter vibration is established in detailed way. Then, on the foundation of modeling, a novel identification method is developed, in which the dynamic undeformed chip thickness could be obtained by using collected data. In a carefully designed experiment procedure, the reliability of model is validated by comparing predicted and measured results. Under different cutting condition and cutter stiffness, data is collected for the justification of identification method. The results showed divergence in calculated coefficients is acceptable confirming the possibility of accomplishing targets by applying this new method. In discussion, the potential directions of improvement are proposed.

  15. Considering a possible future for Digital Journalism

    Directory of Open Access Journals (Sweden)

    Mark DEUZE

    2017-01-01

    Full Text Available Developments shaping digital journalism seem to speeding up at the start of the 21st century. Social media enable radical new ways to gather and verify sources and information. Hardware and software power innovative storytelling formats, combining platforms and channels, adding interactivity to the news experience. And the global news industry is quickly becoming a networked industry, with startups and other forms of entrepreneurial journalism springing up all over the world. In this essay, I consider a possible future for digital journalism by briefly reviewing first findings from a series of case studies of 21 new small-sized journalism enterprises operating in 11 countries (spread across 5 continents. The overarching research question: seen through their eyes, what does the future of (digital journalism look like? The answers are hopeful.

  16. Quality assurance for fittings considering nuclear technology

    International Nuclear Information System (INIS)

    Kilian, H.J.

    1987-01-01

    Negative experience made during World War II led to the idea of quality assurance being born in the United States. Thoroughly misunderstood, it came to be incorporated in European mechanical engineering. Quality assurance there was initially considered to be a new term for the oganizational combination of all parts of an enterprise dealing with testing. German manufacturers of heavy-duty and safety fittings represented in the international market were compelled at a relatively early date to properly understand and realize a quality assurance programme. But the multi-fariousness of specifications to be applied and great number of the most different parts made eminent demands on the suitability and variability of the products developed. On the basis of 18 quality criteria the article describes the structure of 'quality' and what its consequences are for an effective quality assurance system - suited for all kinds of specifications. (orig.) [de

  17. Considering Subcontractors in Distributed Scrum Teams

    Science.gov (United States)

    Rudzki, Jakub; Hammouda, Imed; Mikkola, Tuomas; Mustonen, Karri; Systä, Tarja

    In this chapter we present our experiences with working with subcontractors in distributed Scrum teams. The context of our experiences is a medium size software service provider company. We present the way the subcontractors are selected and how Scrum practices can be used in real-life projects. We discuss team arrangements and tools used in distributed development teams highlighting aspects that are important when working with subcontractors. We also present an illustrative example where different phases of a project working with subcontractors are described. The example also provides practical tips on work in such projects. Finally, we present a summary of our data that was collected from Scrum and non-Scrum projects implemented over a few years. This chapter should provide a practical point of view on working with subcontractors in Scrum teams for those who are considering such cooperation.

  18. PROJECT MANAGEMENT CONSIDERED IN A 2014 PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    GRAPĂ ADELINA-ROXANA

    2014-05-01

    Full Text Available Project Management has come of age, yet multiple surveys and reports confirm the fact that the majority of projects are challenged. Given the more demanding and strict financial constraints associated with the current fiscal climate, project management is regarded as a tool that can deliver more with less. The literature on Project Management shows that, in spite of advancement in Project Management processes, tools and systems, project success has not significantly improved. This problem raises questions about the value and effectiveness of Project Management and Project Management systems. Programs and projects are considered as strategic assets for the majority of businesses, therefore, the trend of these organizations is to embrace a management by projects culture. The main objective of Project Management nowadays is to ensure programs and projects aligned to a certain strategy and also to provide for every member of an organization the ability to take proactive actions creating additional benefits.

  19. Cannabis arteritis: ever more important to consider.

    Science.gov (United States)

    Santos, Rui Pedro; Resende, Cristina Isabel Pinho; Vieira, Ana Paula; Brito, Celeste

    2017-03-13

    Cannabis arteritis (CA) is a major and underdiagnosed cause of peripheral arterial disease in young patients. A 34-year-old man, daily smoker of 20 cigarettes and two cannabis cigarettes for 14 years, presented with a necrotic plaque of left hallux for 3 weeks. The Doppler ultrasound and angiography were compatible with severe Buerger's disease. Submitted to a revascularisation procedure and hypocoagulation with rivaroxaban. He had ceased smoking but maintained consumption of cannabis. Owing to the persistence of distal necrosis, amputation of the hallux was performed with good evolution. CA is a subtype of Buerger's disease. It is poorly known but increasingly prevalent and manifests in cannabis users regardless of tobacco use. The drug is considered at least a cofactor of the arteriopathy. The most effective treatment is cessation of consumption. Being cannabis one of the most consumed drugs, its mandatory to ask about its use in all young patients with arteriopathy. 2017 BMJ Publishing Group Ltd.

  20. Transmission expansion in an oligopoly considering generation investment equilibrium

    DEFF Research Database (Denmark)

    Taheri, S. Saeid; Kazempour, Jalal; Seyedshenava, Seyedjalal

    2017-01-01

    Transmission expansion planning (TEP) is a sophisticated decision-making problem, especially in an oligopolistic electricity market in which a number of strategic (price-maker) producers compete together. A transmission system planner, who is in charge of making TEP decisions, requires considering...... the future generation investment actions. However, in such an oligopolistic market, each producer makes its own strategic generation investment decisions. This motivates the transmission system planner to consider the generation investment decision-making problem of all producers within its TEP model....... The strategic generation investment problem of each producer can be represented by a complementarity bi-level model. The joint consideration of all bi-level models, one per producer, characterizes the generation investment equilibrium that identifies the future evolution of generation investment in the market...