Behzadi, Azad Esmailov
1999-10-01
The critical behavior of the fully frustrated XY model has remained controversial in spite of almost two decades of related research. In this study, we have developed a new method inspired by Netz and Berker's hard-spin mean- field theory. Our approach for XY models yields results consistent with Monte Carlo simulations as the ratio of antiferromagnetic to ferromagnetic interactions is varied. The method captures two phase transitions clearly separated in temperature for ratios of 0.5, 0.6, and 1.5, with these transitions moving closer together in temperature as the interaction ratio approaches 1.0, the fully frustrated case. From the system's chirality as a function of temperature in the critical region, we calculate the critical exponent β in agreement with an Ising transition for all of the interaction ratios studied, including 1.0. This result provides support for the view that there are two transitions, rather than one transition in a new universality class, occurring in the fully frustrated XY model. Finite size effects in this model can be essentially eliminated by rescaling the local magnetization, the quantity retained self- consistently in our computations. This rescaling scheme also shows excellent results when tested on the two- dimensional Ising model, and the method, as generalized, provides a framework for an analytical approach to complex systems. Monte Carlo simulations of the fully frustrated XY model in a magnetic field provide further evidence of two transitions. The magnetic field breaks the rotational symmetry of the model, but the two-fold chiral degeneracy of the ground state persists in the field. This lower degeneracy with the field present makes Monte Carlo simulations converge more rapidly. The critical exponent δ determined from the sublattice magnetizations as a function of field agrees with the value expected for a Kosterlitz-Thouless transition. Further, the zero-field specific heat obtained by extrapolation from simulations in a
Fricke, Moritz B; Rolfes, Raimund
2013-11-01
The installation of offshore wind farms in the German Exclusive Economic Zone requires the deployment of sonar transponders to prevent collisions with submarines. The general requirements for these systems have been previously worked out by the Research Department for Underwater Acoustics and Marine Geophysics of the Bundeswehr. In this article, the major results of the research project "Investigation of Sonar Transponders for Offshore Wind Farms" are presented. For theoretical investigations a hybrid approach was implemented using the boundary element method to calculate the source directivity and a three-dimensional ray-tracing algorithm to estimate the transmission loss. The angle-dependence of the sound field as well as the weather-dependence of the transmission loss are compared to experimental results gathered at the offshore wind farm alpha ventus, located 45 km north of the island Borkum. While theoretical and experimental results are in general agreement, the implemented model slightly underestimates scattering at the rough sea surface. It is found that the source level of 200 dB re 1 μPa at 1 m is adequate to satisfy the detectability of the warning sequence at distances up to 2 NM (≈3.7 km) within a horizontal sector of ±60° if realistic assumptions about signal-processing and noise are made. An arrangement to enlarge the angular coverage is discussed.
Onisko, Agnieszka; Druzdzel, Marek J; Austin, R Marshall
2016-01-01
Classical statistics is a well-established approach in the analysis of medical data. While the medical community seems to be familiar with the concept of a statistical analysis and its interpretation, the Bayesian approach, argued by many of its proponents to be superior to the classical frequentist approach, is still not well-recognized in the analysis of medical data. The goal of this study is to encourage data analysts to use the Bayesian approach, such as modeling with graphical probabilistic networks, as an insightful alternative to classical statistical analysis of medical data. This paper offers a comparison of two approaches to analysis of medical time series data: (1) classical statistical approach, such as the Kaplan-Meier estimator and the Cox proportional hazards regression model, and (2) dynamic Bayesian network modeling. Our comparison is based on time series cervical cancer screening data collected at Magee-Womens Hospital, University of Pittsburgh Medical Center over 10 years. The main outcomes of our comparison are cervical cancer risk assessments produced by the three approaches. However, our analysis discusses also several aspects of the comparison, such as modeling assumptions, model building, dealing with incomplete data, individualized risk assessment, results interpretation, and model validation. Our study shows that the Bayesian approach is (1) much more flexible in terms of modeling effort, and (2) it offers an individualized risk assessment, which is more cumbersome for classical statistical approaches.
Wijk, van M.T.
2007-01-01
Ecosystem functioning is the result of processes working at a hierarchy of scales. The representation of these processes in a model that is mathematically tractable and ecologically meaningful is a big challenge. In this paper I describe an individual based model (PLACO¿PLAnt COmpetition) that
International Nuclear Information System (INIS)
Szyniszewski, Marcin; Manchester Univ.; Cichy, Krzysztof; Poznan Univ.; Kujawa-Cichy, Agnieszka
2014-10-01
We employ exact diagonalization with strong coupling expansion to the massless and massive Schwinger model. New results are presented for the ground state energy and scalar mass gap in the massless model, which improve the precision to nearly 10 -9 %. We also investigate the chiral condensate and compare our calculations to previous results available in the literature. Oscillations of the chiral condensate which are present while increasing the expansion order are also studied and are shown to be directly linked to the presence of flux loops in the system.
Directory of Open Access Journals (Sweden)
Yogang Singh
2017-06-01
Full Text Available Underwater gliders are buoyancy propelled vehicle which make use of buoyancy for vertical movement and wings to propel the glider in forward direction. Autonomous underwater gliders are a patented technology and are manufactured and marketed by corporations. In this study, we validate the experimental lift and drag characteristics of a glider from the literature using Computational fluid dynamics (CFD approach. This approach is then used for the assessment of the steady state characteristics of a laboratory glider designed at Indian Institute of Technology (IIT Madras. Flow behaviour and lift and drag force distribution at different angles of attack are studied for Reynolds numbers varying from 105 to 106 for NACA0012 wing configurations. The state variables of the glider are the velocity, gliding angle and angle of attack which are simulated by making use of the hydrodynamic drag and lift coefficients obtained from CFD. The effect of the variable buoyancy is examined in terms of the gliding angle, velocity and angle of attack. Laboratory model of glider is developed from the final design asserted by CFD. This model is used for determination of static and dynamic properties of an underwater glider which were validated against an equivalent CAD model and simulation results obtained from equations of motion of glider in vertical plane respectively. In the literature, only empirical approach has been adopted to estimate the hydrodynamic coefficients of the AUG that are required for its trajectory simulation. In this work, a CFD approach has been proposed to estimate the hydrodynamic coefficients and validated with experimental data. A two-mass variable buoyancy engine has been designed and implemented. The equations of motion for this two-mass engine have been obtained by modifying the single mass version of the equations described in the literature. The objectives of the present study are to understand the glider dynamics adopting a CFD approach
Li, L.; Yang, C.
2017-12-01
Climate extremes often manifest as rare events in terms of surface air temperature and precipitation with an annual reoccurrence period. In order to represent the manifold characteristics of climate extremes for monitoring and analysis, the Expert Team on Climate Change Detection and Indices (ETCCDI) had worked out a set of 27 core indices based on daily temperature and precipitation data, describing extreme weather and climate events on an annual basis. The CLIMDEX project (http://www.climdex.org) had produced public domain datasets of such indices for data from a variety of sources, including output from global climate models (GCM) participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5). Among the 27 ETCCDI indices, there are six percentile-based temperature extremes indices that may fall into two groups: exceedance rates (ER) (TN10p, TN90p, TX10p and TX90p) and durations (CSDI and WSDI). Percentiles must be estimated prior to the calculation of the indices, and could more or less be biased by the adopted algorithm. Such biases will in turn be propagated to the final results of indices. The CLIMDEX used an empirical quantile estimator combined with a bootstrap resampling procedure to reduce the inhomogeneity in the annual series of the ER indices. However, there are still some problems remained in the CLIMDEX datasets, namely the overestimated climate variability due to unaccounted autocorrelation in the daily temperature data, seasonally varying biases and inconsistency between algorithms applied to the ER indices and to the duration indices. We now present new results of the six indices through a semiparametric quantile regression approach for the CMIP5 model output. By using the base-period data as a whole and taking seasonality and autocorrelation into account, this approach successfully addressed the aforementioned issues and came out with consistent results. The new datasets cover the historical and three projected (RCP2.6, RCP4.5 and RCP
Atmospheric Deposition Modeling Results
U.S. Environmental Protection Agency — This asset provides data on model results for dry and total deposition of sulfur, nitrogen and base cation species. Components include deposition velocities, dry...
Directory of Open Access Journals (Sweden)
Michael Fröhlich
2013-10-01
Full Text Available In Olympic-distance triathlon, time minimization is the goal in all three disciplines and the two transitions. Running is the key to winning, whereas swimming and cycling performance are less significantly associated with overall competition time. A comparative static simulation calculation based on the individual times of each discipline was done. Furthermore, the share of the discipline in the total time proved that increasing the scope of running training results in an additional performance development. Looking at the current development in triathlon and taking the Olympic Games in London 2012 as an initial basis for model-theoretic simulations of performance development, the first fact that attracts attention is that running becomes more and more the crucial variable in terms of winning a triathlon. Run times below 29:00 minutes in Olympic-distance triathlon will be decisive for winning. Currently, cycle training time is definitely overrepresented. The share of swimming is considered optimal.
Westenbroek, Stephen M.; Doherty, John; Walker, John F.; Kelson, Victor A.; Hunt, Randall J.; Cera, Timothy B.
2012-01-01
The TSPROC (Time Series PROCessor) computer software uses a simple scripting language to process and analyze time series. It was developed primarily to assist in the calibration of environmental models. The software is designed to perform calculations on time-series data commonly associated with surface-water models, including calculation of flow volumes, transformation by means of basic arithmetic operations, and generation of seasonal and annual statistics and hydrologic indices. TSPROC can also be used to generate some of the key input files required to perform parameter optimization by means of the PEST (Parameter ESTimation) computer software. Through the use of TSPROC, the objective function for use in the model-calibration process can be focused on specific components of a hydrograph.
DEFF Research Database (Denmark)
Nielsen, Tine; Kreiner, Svend
2011-01-01
. For self-assessment, self-scoring and self-interpretational purposes it is deemed prudent that subscales measuring comparable constructs are of the same item length. Consequently, in order to obtain a self-assessment version of the R-D-LSI with an equal number of items in each subscale, a systematic...... approach to item reduction based on results of graphical loglinear Rasch modeling (GLLRM) was designed. This approach was then used to reduce the number of items in the subscales of the R-D-LSI which had an item-length of more than seven items, thereby obtaining the Danish Self-Assessment Learning Styles...
Gueyffier, François; Strang, Catherine Brun; Berdeaux, Gilles; França, Lionel Riou; Blin, Patrick; Massol, Jacques
2012-01-01
Modeling consists in aggregating separate pieces of knowledge, according to a given structure and rules. It allows studying the behavior of more or less complex systems by simulation techniques. Modeling is used in different state-of-the-art technological domains (meteorology, aeronautics). Its use has grown for the evaluation of medicines and medical devices, from conception to prescription (marketing authorization, reimbursement, price setting and re-registrations). It follows a scientific approach and is the object of good practice recommendations. Coupling models to virtual populations allows obtaining realistic results at the population level, testing diagnostic or therapeutic strategies, as well as estimating the consequences of transposing the results of clinical trials to the population. Through examples, the participants of the Round Table analyzed the contributions of the coupling of models and realistic virtual populations, and proposed guidelines for their judicious and systematic use. © 2012 Société Française de Pharmacologie et de Thérapeutique.
Barrett, Samuel; Webster, Jody
2016-04-01
Numerical simulation of the stratigraphy and sedimentology of carbonate systems (carbonate forward stratigraphic modelling - CFSM) provides significant insight into the understanding of both the physical nature of these systems and the processes which control their development. It also provides the opportunity to quantitatively test conceptual models concerning stratigraphy, sedimentology or geomorphology, and allows us to extend our knowledge either spatially (e.g. between bore holes) or temporally (forwards or backwards in time). The later is especially important in determining the likely future development of carbonate systems, particularly regarding the effects of climate change. This application, by its nature, requires successful simulation of carbonate systems on short time scales and at high spatial resolutions. Previous modelling attempts have typically focused on the scales of kilometers and kilo-years or greater (the scale of entire carbonate platforms), rather than at the scale of centuries or decades, and tens to hundreds of meters (the scale of individual reefs). Previous work has identified limitations in common approaches to simulating important reef processes. We present a new CFSM, Reef Sedimentary Accretion Model (ReefSAM), which is designed to test new approaches to simulating reef-scale processes, with the aim of being able to better simulate the past and future development of coral reefs. Four major features have been tested: 1. A simulation of wave based hydrodynamic energy with multiple simultaneous directions and intensities including wave refraction, interaction, and lateral sheltering. 2. Sediment transport simulated as sediment being moved from cell to cell in an iterative fashion until complete deposition. 3. A coral growth model including consideration of local wave energy and composition of the basement substrate (as well as depth). 4. A highly quantitative model testing approach where dozens of output parameters describing the reef
International Nuclear Information System (INIS)
Shipler, D.B.; Napier, B.A.
1992-07-01
This report details the conceptual approaches to be used in calculating radiation doses to individuals throughout the various periods of operations at the Hanford Site. The report considers the major environmental transport pathways--atmospheric, surface water, and ground water--and projects and appropriate modeling technique for each. The modeling sequence chosen for each pathway depends on the available data on doses, the degree of confidence justified by such existing data, and the level of sophistication deemed appropriate for the particular pathway and time period being considered
Modeling prosody: Different approaches
Carmichael, Lesley M.
2002-11-01
Prosody pervades all aspects of a speech signal, both in terms of raw acoustic outcomes and linguistically meaningful units, from the phoneme to the discourse unit. It is carried in the suprasegmental features of fundamental frequency, loudness, and duration. Several models have been developed to account for the way prosody organizes speech, and they vary widely in terms of their theoretical assumptions, organizational primitives, actual procedures of application to speech, and intended use (e.g., to generate speech from text vs. to model the prosodic phonology of a language). In many cases, these models overtly contradict one another with regard to their fundamental premises or their identification of the perceptible objects of linguistic prosody. These competing models are directly compared. Each model is applied to the same speech samples. This parallel analysis allows for a critical inspection of each model and its efficacy in assessing the suprasegmental behavior of the speech. The analyses illustrate how different approaches are better equipped to account for different aspects of prosody. Viewing the models and their successes from an objective perspective allows for creative possibilities in terms of combining strengths from models which might otherwise be considered fundamentally incompatible.
Norman, L.M.; Guertin, D.P.; Feller, M.
2008-01-01
The development of new approaches for understanding processes of urban development and their environmental effects, as well as strategies for sustainable management, is essential in expanding metropolitan areas. This study illustrates the potential of linking urban growth and watershed models to identify problem areas and support long-term watershed planning. Sediment is a primary source of nonpoint-source pollution in surface waters. In urban areas, sediment is intermingled with other surface debris in transport. In an effort to forecast the effects of development on surface-water quality, changes predicted in urban areas by the SLEUTH urban growth model were applied in the context of erosion-sedimentation models (Universal Soil Loss Equation and Spatially Explicit Delivery Models). The models are used to simulate the effect of excluding hot-spot areas of erosion and sedimentation from future urban growth and to predict the impacts of alternative erosion-control scenarios. Ambos Nogales, meaning 'both Nogaleses,' is a name commonly used for the twin border cities of Nogales, Arizona and Nogales, Sonora, Mexico. The Ambos Nogales watershed has experienced a decrease in water quality as a result of urban development in the twin-city area. Population growth rates in Ambos Nogales are high and the resources set in place to accommodate the rapid population influx will soon become overburdened. Because of its remote location and binational governance, monitoring and planning across the border is compromised. One scenario described in this research portrays an improvement in water quality through the identification of high-risk areas using models that simulate their protection from development and replanting with native grasses, while permitting the predicted and inevitable growth elsewhere. This is meant to add to the body of knowledge about forecasting the impact potential of urbanization on sediment delivery to streams for sustainable development, which can be
Schmitt, R. J.; Bernardi, D.; Bizzi, S.; Castelletti, A.; Soncini-Sessa, R.
2013-12-01
sediment balance over an extended time-horizon (>15 yrs.), upstream impoundments induce a much more rapid adaptation (1-5 yrs.). The applicability of the ANN as predictive model was evaluated by comparing its results with a traditional, 1D bed evolution model. The next decade's morphologic evolution under an ensemble of scenarios, considering uncertainties in climatic change, socio-economic development and upstream reservoir release policies was derived from both models. The ANN greatly outperforms the 1D model in computational requirements and presents a powerful tool for effective assessment of scenario ensembles and quantification of uncertainties in river hydro-morphology. In contrast, the processes-based model provides detailed, spatio-temporally distributed outputs and validation of the ANN's results for selected scenarios. We conclude that the application of both approaches constitutes a mutually enriching strategy for modern, quantitative catchment management. We argue that physically based modeling can have specific spatial and temporal constrains (e.g. in terms of identifying key drivers and associated temporal and spatial domains) and that linking physically-based with data-driven approaches largely increases the potential for including hydro-morphology into basin-scale water resource management.
Directory of Open Access Journals (Sweden)
J. Güldner
2013-10-01
of model-based regression operators in order to provide unbiased vertical profiles during the campaign at Munich Airport. The results of this algorithm and the retrievals of a neural network, specially developed for the site, are compared with radiosondes from Oberschleißheim located about 10 km apart from the MWRP site. Outstanding deviations for the lowest levels between 50 and 100 m are discussed. Analogously to the airport experiment, a model-based regression operator was calculated for Lindenberg and compared with both radiosondes and operational results of observation-based methods. The bias of the retrievals could be considerably reduced and the accuracy, which has been assessed for the airport site, is quite similar to those of the operational radiometer site at Lindenberg above 1 km height. Additional investigations are made to determine the length of the training period necessary for generating best estimates. Thereby three months have proven to be adequate. The results of the study show that on the basis of numerical weather prediction (NWP model data, available everywhere at any time, the model-based regression method is capable of providing comparable results at a multitude of sites. Furthermore, the approach offers auspicious conditions for automation and continuous updating.
Directory of Open Access Journals (Sweden)
Ulrike Lehr
2012-02-01
Full Text Available National studies have shown that both gross and net effects of the expansion of energy from renewable sources on employment are positive for Germany. These modeling approaches also revealed that this holds true for both present and future perspectives under certain assumptions on the development of exports, fossil fuel prices and national politics. Yet how are employment effects distributed within Germany? What components contribute to growth impacts on a regional level? To answer these questions (new methods of regionalization were explored and developed for the example “wind energy onshore” for Germany’s federal states. The main goal was to develop a methodology which is applicable to all renewable energy technologies in future research. For the quantification and projection, it was necessary to distinguish between jobs generated by domestic investments and exports on the one hand, and jobs for operation and maintenance of existing plants on the other hand. Further, direct and indirect employment is analyzed. The results show, that gross employment is particularly high in the northwestern regions of Germany. However, especially the indirect effects are spread out over the whole country. Regions in the south not only profit from the delivery of specific components, but also from other industry and service inputs.
Material Modelling - Composite Approach
DEFF Research Database (Denmark)
Nielsen, Lauge Fuglsang
1997-01-01
This report is part of a research project on "Control of Early Age Cracking" - which, in turn, is part of the major research programme, "High Performance Concrete - The Contractor's Technology (HETEK)", coordinated by the Danish Road Directorate, Copenhagen, Denmark, 1997.A composite-rheological ......This report is part of a research project on "Control of Early Age Cracking" - which, in turn, is part of the major research programme, "High Performance Concrete - The Contractor's Technology (HETEK)", coordinated by the Danish Road Directorate, Copenhagen, Denmark, 1997.A composite......-rheological model of concrete is presented by which consistent predictions of creep, relaxation, and internal stresses can be made from known concrete composition, age at loading, and climatic conditions. No other existing "creep prediction method" offers these possibilities in one approach.The model...... in this report is that cement paste and concrete behave practically as linear-viscoelastic materials from an age of approximately 10 hours. This is a significant age extension relative to earlier studies in the literature where linear-viscoelastic behavior is only demonstrated from ages of a few days. Thus...
Campanya i Llovet, J.; Ogaya, X.; Jones, A. G.; Rath, V.
2014-12-01
The IRECCSEM project (www.ireccsem.ie) is a Science Foundation Ireland Investigator Project that is funded to evaluate Ireland's potential for onshore carbon sequestration in saline aquifers by integrating new electromagnetic data with existing geophysical and geological data. The main goals of the project are to determine porosity-permeability values of the potential reservoir formation as well as to evaluate the integrity of the seal formation. During the Summer of 2014 a magnetotelluric (MT) survey was carried out at the Clare basin (Ireland). A total of 140 sites were acquired including audiomagnetotelluric (AMT), broadband magnetotelluric (BBMT) and long period magnetotelluric (LMT) data. The nominal space between sites is 0.6 km for AMT sites, 1.2 km for BBMT sites and 8 km for LMT sites. To evaluate the potential for carbon sequestration of the Clare basin three advances on geophysical methodology related to electromagnetic techniques were applied. First of all, processing of the MT data was improved following the recently published ELICIT methodology. Secondly, during the inversion process, the electrical resistivity distribution of the subsurface was constrained combining three different tensor relationships: Impedances (Z), induction arrows (TIP) and multi-site horizontal magnetic transfer-functions (HMT). Results from synthetic models were used to evaluate the sensitivity and properties of each tensor relationship. Finally, a computer code was developed, which employs a stabilized least squares approach to estimate the cementation exponent in the generalized Archie law formulated by Glover (2010). This allows relating MT-derived electrical resistivity models to porosity distributions. The final aim of this procedure is to generalize the porosity - permeability values measured in the boreholes to regional scales. This methodology will contribute to the evaluation of possible sequestration targets in the study area.
Gaspar, Leticia; White, Sue; Navas, Ana; López-Vicente, Manuel; Palazón, Leticia
2013-04-01
Modelling runoff and sediment transport at watershed scale are key tools to predict hydrological and sediment processes, identify soil sediment sources and estimate sediment yield, with the purpose of better managing soil and water resources. This study aims to apply the SWAT model in an endorheic watershed in the Central Spanish Pre-Pyrenees, where there have been a number of previous field-based studies on sediment sources and transfers. The Soil and Water Assessment Tool (SWAT) is a process based semi-distributed watershed scale hydrologic model, which can provide a high level of spatial detail by allowing the watershed to be divided into sub-basins. This study addresses the challenge of applying the SWAT model to an endorheic watershed that drains to a central lake, without external output, and without a network of permanent rivers. In this case it has been shown that the SWAT model does not correctly reproduce the stream network when using automatic watershed delineation, even with a high resolution Digital Elevation Model (5 x 5 metres). For this purpose, different approaches needed to be considered, such as i) user-defined watersheds and streams, ii) burning in a stream network or iii) modelling each sub-watershed separately. The objective of this study was to develop a new methodological approach for correctly simulating the main hydrological processes in an endorheic and complex karst watershed of the Spanish Pre-Pyrenees. The Estanque de Arriba Lake watershed (74 ha) is an endorheic system located in the Spanish Central Pre-Pyrenees. This watershed holds a small and permanent lake of fresh water (1.7 ha) and is a Site of Community Importance (European NATURA 2000 network). The study area is characterized by an abrupt topography with altitude range between 679 and 862 m and an average slope gradient of 24 %. Steep slopes (> 24 %) occupy the northern part of the watershed, whereas gentle slopes (
Bossen, Claus; Jensen, Lotte Groth; Udsen, Flemming Witt
2013-10-01
difficult, but was required because a key role was to inform decision-making upon enrollment at other hospitals and systematically identify barriers in this respect. The strength of the evaluation is the mixed-methods approach. Further, the evaluation was based on assessments from staff in two departments that comprise around 50% of hospital staff. A weakness may be that staff assessment plays a major role in interviews and survey. These though are supplemented by performance data and observation. Also, the evaluation primarily reports upon the dimension 'user satisfaction', since use of the EHR is mandatory. Finally, generalizability may be low, since the evaluation was not based on a validated survey. All in all, however, the evaluation proposes an evaluation design in constrained circumstances. Despite inherent limitations, evaluation of a comprehensive EHR shortly after implementation may be necessary, can be conducted, and may inform political decision making. The updated DeLone and McLean framework was constructive in the overall design of the evaluation of the EHR implementation, and allowed the model to be adapted to the health care domain by being methodological flexible. The mixed-methods case study produced valid and reliable results, and was accepted by staff, system providers, and political decision makers. The successful implementation may be attributed to the configurability of the EHR and to factors such as an experienced, competent implementation organization at the hospital, upgraded soft- and hardware, and a high degree of user involvement. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
International Nuclear Information System (INIS)
Kaneoya, Katsuhiko; Ueda, Takuya; Suito, Hiroshi
2008-01-01
The aim of this study was to establish functional computed tomography (CT) imaging as a method for assessing tumor-induced angiogenesis. Functional CT imaging was mathematically analyzed for 14 renal cell carcinomas by means of two-compartment modeling using a computer-discretization approach. The model incorporated diffusible kinetics of contrast medium including leakage from the capillary to the extravascular compartment and back-flux to the capillary compartment. The correlations between functional CT parameters [relative blood volume (rbv), permeability 1 (Pm1), and permeability 2 (Pm2)] and histopathological markers of angiogenesis [microvessel density (MVD) and vascular endothelial growth factor (VEGF)] were statistically analyzed. The modeling was successfully performed, showing similarity between the mathematically simulated curve and the measured time-density curve. There were significant linear correlations between MVD grade and Pm1 (r=0.841, P=0.001) and between VEGF grade and Pm2 (r=0.804, P=0.005) by Pearson's correlation coefficient. This method may be a useful tool for the assessment of tumor-induced angiogenesis. (author)
DEFF Research Database (Denmark)
Bossen, Claus; Jensen, Lotte Groth; Udsen, Flemming Witt
2013-01-01
Objective: The article describes the methodological approach to, and results of an evaluation of a comprehensive electronic health record (EHR) in the shake down phase, shortly after its implementation at a regional hospital in Denmark. Design: A formative evaluation based on a mixed-methods case...... study, designed to be interactive and concurrent was conducted at two hospital departments based on the updated DeLone and McLean framework for evaluating information systems success. Methods: To ascertain user assessments of the EHR, we distributed a questionnaire two months after implementation......:Overall, staff had positive experiences with the EHR and its operational reliability, response time, login and support. Performance was acceptable. Medical secretaries found the use of the patient administration module cumbersome, and physicians found the establishment of the overview of professionally...
Interdisciplinary approach for improved esthetic results
Directory of Open Access Journals (Sweden)
G Sriram
2014-01-01
Full Text Available This clinical report describes an interdisciplinary (orthodontic, prosthodontics and operative dentist approach for the coordinated treatment of an adult patient diagnosed with severely mutilated dentition secondary to caries lesion warranting restorative procedures that was facilitated with orthodontic treatment. The patient′s specific esthetic expectation for the anterior teeth and improved smile were successfully met through planned treatment, including orthodontic tooth movement, restoration and porcelain conversion crowns. Such coordinated interdisciplinary evaluations and treatment are necessary for improved esthetics.
System Behavior Models: A Survey of Approaches
2016-06-01
the Petri model allowed a quick assessment of all potential states but was more cumbersome to build than the MP model. A comparison of approaches...identical state space results. The combined state space graph of the Petri model allowed a quick assessment of all potential states but was more...59 INITIAL DISTRIBUTION LIST ...................................................................................65 ix LIST
VEMAP 1: Selected Model Results
National Aeronautics and Space Administration — The Vegetation/Ecosystem Modeling and Analysis Project (VEMAP) was a multi-institutional, international effort addressing the response of biogeography and...
VEMAP 1: Selected Model Results
National Aeronautics and Space Administration — ABSTRACT: The Vegetation/Ecosystem Modeling and Analysis Project (VEMAP) was a multi-institutional, international effort addressing the response of biogeography and...
Page, Timothy F; Amofah, St Anthony; McCann, Shelia; Rivo, Julie; Varghese, Asha; James, Terisa; Rivo, Marc; Williams, Mark L
2015-07-01
This article presents preliminary findings of the impact of an innovative care management model for diabetic patients. The model was implemented by seven Federally Qualified Health Centers serving 10,000 diabetic patients in Miami-Dade County. A primary intervention of this model is a centralized care management team that makes previsit phone calls to diabetic patients who have scheduled appointments. These previsit phone calls optimize patient knowledge and self-management goals, and provide patient care coordinators with relevant clinical information to optimize the office visit and help to ensure completion of recommended diabetic preventive and chronic care services. Data suggest that following the implementation of this care management model, more diabetic patients are receiving regular care, and compliance with recommended tests and screenings has improved. © 2015 Society for Public Health Education.
Results of a Flipped Classroom Teaching Approach in Anesthesiology Residents.
Martinelli, Susan M; Chen, Fei; DiLorenzo, Amy N; Mayer, David C; Fairbanks, Stacy; Moran, Kenneth; Ku, Cindy; Mitchell, John D; Bowe, Edwin A; Royal, Kenneth D; Hendrickse, Adrian; VanDyke, Kenneth; Trawicki, Michael C; Rankin, Demicha; Guldan, George J; Hand, Will; Gallagher, Christopher; Jacob, Zvi; Zvara, David A; McEvoy, Matthew D; Schell, Randall M
2017-08-01
In a flipped classroom approach, learners view educational content prior to class and engage in active learning during didactic sessions. We hypothesized that a flipped classroom improves knowledge acquisition and retention for residents compared to traditional lecture, and that residents prefer this approach. We completed 2 iterations of a study in 2014 and 2015. Institutions were assigned to either flipped classroom or traditional lecture for 4 weekly sessions. The flipped classroom consisted of reviewing a 15-minute video, followed by 45-minute in-class interactive sessions with audience response questions, think-pair-share questions, and case discussions. The traditional lecture approach consisted of a 55-minute lecture given by faculty with 5 minutes for questions. Residents completed 3 knowledge tests (pretest, posttest, and 4-month retention) and surveys of their perceptions of the didactic sessions. A linear mixed model was used to compare the effect of both formats on knowledge acquisition and retention. Of 182 eligible postgraduate year 2 anesthesiology residents, 155 (85%) participated in the entire intervention, and 142 (78%) completed all tests. The flipped classroom approach improved knowledge retention after 4 months (adjusted mean = 6%; P = .014; d = 0.56), and residents preferred the flipped classroom (pre = 46%; post = 82%; P < .001). The flipped classroom approach to didactic education resulted in a small improvement in knowledge retention and was preferred by anesthesiology residents.
Hybrid approaches to physiologic modeling and prediction
Olengü, Nicholas O.; Reifman, Jaques
2005-05-01
This paper explores how the accuracy of a first-principles physiological model can be enhanced by integrating data-driven, "black-box" models with the original model to form a "hybrid" model system. Both linear (autoregressive) and nonlinear (neural network) data-driven techniques are separately combined with a first-principles model to predict human body core temperature. Rectal core temperature data from nine volunteers, subject to four 30/10-minute cycles of moderate exercise/rest regimen in both CONTROL and HUMID environmental conditions, are used to develop and test the approach. The results show significant improvements in prediction accuracy, with average improvements of up to 30% for prediction horizons of 20 minutes. The models developed from one subject's data are also used in the prediction of another subject's core temperature. Initial results for this approach for a 20-minute horizon show no significant improvement over the first-principles model by itself.
Directory of Open Access Journals (Sweden)
GÎNŢA ANCA IOANA
2015-12-01
Full Text Available This article is trying to tackle the relationships which exist between three dimensions of economic reality. The objective of this article is to contribute to the study of determinants of accounting result management. The accounting result management deviates from the accounting principles (honesty, regularity and faithful image and finds its motivations in the contractual relations between the managers and stakeholders. This is in the legal, not more frame. The appreciation of accounting information players is different, their interests are different. Therefore, the flexibility of accounting rules allowed to the managers is opportunistic. The accounting representation cannot be completely objective, it is more or less subjective, but the freedom of judgment should be based on a high level of ethical sensibility. The ethical side in accounting has something to say about the result management, it allows the result to offer a faithful image.
Learning Action Models: Qualitative Approach
Bolander, T.; Gierasimczuk, N.; van der Hoek, W.; Holliday, W.H.; Wang, W.-F.
2015-01-01
In dynamic epistemic logic, actions are described using action models. In this paper we introduce a framework for studying learnability of action models from observations. We present first results concerning propositional action models. First we check two basic learnability criteria: finite
Büssing, Arndt; Recchia, Daniela R
2016-06-01
In an anonym cross-sectional survey (using standardized questionnaires) among 1092 German soldiers, we found that 21 % regard their faith as a "strong hold in difficult times." Only a few had specific religious needs. Rather, a consistent theme from the participants was the need to communicate their own fears, worries and desire to attain states of inner peace. "Soldiers" stress perception and posttraumatic stress disorder symptoms were associated particularly with existential and Inner Peace Needs. Structural equation modeling indicated that stress perception has a negative influence on soldiers' life satisfaction, which in turn gives rise to specific unmet spiritual needs. These specific needs may indicate psycho-emotional problems which could be supported very early to prevent health affections and service failure.
HEDR modeling approach: Revision 1
International Nuclear Information System (INIS)
Shipler, D.B.; Napier, B.A.
1994-05-01
This report is a revision of the previous Hanford Environmental Dose Reconstruction (HEDR) Project modeling approach report. This revised report describes the methods used in performing scoping studies and estimating final radiation doses to real and representative individuals who lived in the vicinity of the Hanford Site. The scoping studies and dose estimates pertain to various environmental pathways during various periods of time. The original report discussed the concepts under consideration in 1991. The methods for estimating dose have been refined as understanding of existing data, the scope of pathways, and the magnitudes of dose estimates were evaluated through scoping studies
HEDR modeling approach: Revision 1
Energy Technology Data Exchange (ETDEWEB)
Shipler, D.B.; Napier, B.A.
1994-05-01
This report is a revision of the previous Hanford Environmental Dose Reconstruction (HEDR) Project modeling approach report. This revised report describes the methods used in performing scoping studies and estimating final radiation doses to real and representative individuals who lived in the vicinity of the Hanford Site. The scoping studies and dose estimates pertain to various environmental pathways during various periods of time. The original report discussed the concepts under consideration in 1991. The methods for estimating dose have been refined as understanding of existing data, the scope of pathways, and the magnitudes of dose estimates were evaluated through scoping studies.
Modeling Approaches in Planetary Seismology
Weber, Renee; Knapmeyer, Martin; Panning, Mark; Schmerr, Nick
2014-01-01
Of the many geophysical means that can be used to probe a planet's interior, seismology remains the most direct. Given that the seismic data gathered on the Moon over 40 years ago revolutionized our understanding of the Moon and are still being used today to produce new insight into the state of the lunar interior, it is no wonder that many future missions, both real and conceptual, plan to take seismometers to other planets. To best facilitate the return of high-quality data from these instruments, as well as to further our understanding of the dynamic processes that modify a planet's interior, various modeling approaches are used to quantify parameters such as the amount and distribution of seismicity, tidal deformation, and seismic structure on and of the terrestrial planets. In addition, recent advances in wavefield modeling have permitted a renewed look at seismic energy transmission and the effects of attenuation and scattering, as well as the presence and effect of a core, on recorded seismograms. In this chapter, we will review these approaches.
One approach for Management by Objectives and Results in Scandinavia?
DEFF Research Database (Denmark)
Kristiansen, Mads Bøge
2016-01-01
Viewed from abroad, Denmark, Norway and Sweden look very similar. In the literature on public management reforms and performance management, these countries are frequently regarded as one, and the literature often refers to a specific Nordic or Scandinavian model. The aim of this paper...... is to empirically test the argument concerning the existence of one Nordic perspective on performance management. The paper presents a comparative study of Management by Objectives and Results (MBOR) in Prison and Probation Services, Food Safety, and Meteorology in Denmark, Norway and Sweden. The paper examines...... differences and similarities in the design and use of MBOR across the countries (within each of the different tasks), and within each of the three countries (across the three tasks). The paper finds that it is difficult to identify one Scandinavian approach to MBOR, as variations in MBOR are observed across...
Business jet approach noise abatement techniques - Flight test results
Putnam, T. W.; Burcham, F. W.
1976-01-01
Operational techniques for reducing approach noise from business jet aircraft were evaluated in flight by measuring the noise generated by five such aircraft during modified approaches. Approaches with 4-deg glide slopes were approximately 4.0 EPNdB quieter than approaches with standard 3-deg glide slopes. Noise reductions for low-drag 3-deg approaches varied widely among the airplanes tested; the fleet-weighted reduction was 8.5 EPNdB. Two-segment approaches resulted in noise reductions of 7.0 EPNdB to 8.5 EPNdB 3 nautical miles and 5 nautical miles from touchdown. Pilot workload increased progressively for the 4-deg, low-drag 3-deg, and two-segment approach.
Towards new approaches in phenological modelling
Chmielewski, Frank-M.; Götz, Klaus-P.; Rawel, Harshard M.; Homann, Thomas
2014-05-01
Modelling of phenological stages is based on temperature sums for many decades, describing both the chilling and the forcing requirement of woody plants until the beginning of leafing or flowering. Parts of this approach go back to Reaumur (1735), who originally proposed the concept of growing degree-days. Now, there is a growing body of opinion that asks for new methods in phenological modelling and more in-depth studies on dormancy release of woody plants. This requirement is easily understandable if we consider the wide application of phenological models, which can even affect the results of climate models. To this day, in phenological models still a number of parameters need to be optimised on observations, although some basic physiological knowledge of the chilling and forcing requirement of plants is already considered in these approaches (semi-mechanistic models). Limiting, for a fundamental improvement of these models, is the lack of knowledge about the course of dormancy in woody plants, which cannot be directly observed and which is also insufficiently described in the literature. Modern metabolomic methods provide a solution for this problem and allow both, the validation of currently used phenological models as well as the development of mechanistic approaches. In order to develop this kind of models, changes of metabolites (concentration, temporal course) must be set in relation to the variability of environmental (steering) parameters (weather, day length, etc.). This necessarily requires multi-year (3-5 yr.) and high-resolution (weekly probes between autumn and spring) data. The feasibility of this approach has already been tested in a 3-year pilot-study on sweet cherries. Our suggested methodology is not only limited to the flowering of fruit trees, it can be also applied to tree species of the natural vegetation, where even greater deficits in phenological modelling exist.
Branding approach and valuation models
Directory of Open Access Journals (Sweden)
Mamula Tatjana
2006-01-01
Full Text Available Much of the skill of marketing and branding nowadays is concerned with building equity for products whose characteristics, pricing, distribution and availability are really quite close to each other. Brands allow the consumer to shop with confidence. The real power of successful brands is that they meet the expectations of those that buy them or, to put it another way, they represent a promise kept. As such they are a contract between a seller and a buyer: if the seller keeps to its side of the bargain, the buyer will be satisfied; if not, the buyer will in future look elsewhere. Understanding consumer perceptions and associations is an important first step to understanding brand preferences and choices. In this paper, we discuss different models to measure value of brand according to couple of well known approaches according to request by companies. We rely upon several empirical examples.
A multiscale modeling approach for biomolecular systems
Energy Technology Data Exchange (ETDEWEB)
Bowling, Alan, E-mail: bowling@uta.edu; Haghshenas-Jaryani, Mahdi, E-mail: mahdi.haghshenasjaryani@mavs.uta.edu [The University of Texas at Arlington, Department of Mechanical and Aerospace Engineering (United States)
2015-04-15
This paper presents a new multiscale molecular dynamic model for investigating the effects of external interactions, such as contact and impact, during stepping and docking of motor proteins and other biomolecular systems. The model retains the mass properties ensuring that the result satisfies Newton’s second law. This idea is presented using a simple particle model to facilitate discussion of the rigid body model; however, the particle model does provide insights into particle dynamics at the nanoscale. The resulting three-dimensional model predicts a significant decrease in the effect of the random forces associated with Brownian motion. This conclusion runs contrary to the widely accepted notion that the motor protein’s movements are primarily the result of thermal effects. This work focuses on the mechanical aspects of protein locomotion; the effect ATP hydrolysis is estimated as internal forces acting on the mechanical model. In addition, the proposed model can be numerically integrated in a reasonable amount of time. Herein, the differences between the motion predicted by the old and new modeling approaches are compared using a simplified model of myosin V.
Neural network approaches for noisy language modeling.
Li, Jun; Ouazzane, Karim; Kazemian, Hassan B; Afzal, Muhammad Sajid
2013-11-01
Text entry from people is not only grammatical and distinct, but also noisy. For example, a user's typing stream contains all the information about the user's interaction with computer using a QWERTY keyboard, which may include the user's typing mistakes as well as specific vocabulary, typing habit, and typing performance. In particular, these features are obvious in disabled users' typing streams. This paper proposes a new concept called noisy language modeling by further developing information theory and applies neural networks to one of its specific application-typing stream. This paper experimentally uses a neural network approach to analyze the disabled users' typing streams both in general and specific ways to identify their typing behaviors and subsequently, to make typing predictions and typing corrections. In this paper, a focused time-delay neural network (FTDNN) language model, a time gap model, a prediction model based on time gap, and a probabilistic neural network model (PNN) are developed. A 38% first hitting rate (HR) and a 53% first three HR in symbol prediction are obtained based on the analysis of a user's typing history through the FTDNN language modeling, while the modeling results using the time gap prediction model and the PNN model demonstrate that the correction rates lie predominantly in between 65% and 90% with the current testing samples, and 70% of all test scores above basic correction rates, respectively. The modeling process demonstrates that a neural network is a suitable and robust language modeling tool to analyze the noisy language stream. The research also paves the way for practical application development in areas such as informational analysis, text prediction, and error correction by providing a theoretical basis of neural network approaches for noisy language modeling.
A Bayesian approach to model uncertainty
International Nuclear Information System (INIS)
Buslik, A.
1994-01-01
A Bayesian approach to model uncertainty is taken. For the case of a finite number of alternative models, the model uncertainty is equivalent to parameter uncertainty. A derivation based on Savage's partition problem is given
MODELS OF TECHNOLOGY ADOPTION: AN INTEGRATIVE APPROACH
Directory of Open Access Journals (Sweden)
Andrei OGREZEANU
2015-06-01
Full Text Available The interdisciplinary study of information technology adoption has developed rapidly over the last 30 years. Various theoretical models have been developed and applied such as: the Technology Acceptance Model (TAM, Innovation Diffusion Theory (IDT, Theory of Planned Behavior (TPB, etc. The result of these many years of research is thousands of contributions to the field, which, however, remain highly fragmented. This paper develops a theoretical model of technology adoption by integrating major theories in the field: primarily IDT, TAM, and TPB. To do so while avoiding mess, an approach that goes back to basics in independent variable type’s development is proposed; emphasizing: 1 the logic of classification, and 2 psychological mechanisms behind variable types. Once developed these types are then populated with variables originating in empirical research. Conclusions are developed on which types are underpopulated and present potential for future research. I end with a set of methodological recommendations for future application of the model.
An equilibrium approach to modelling social interaction
Gallo, Ignacio
2009-07-01
The aim of this work is to put forward a statistical mechanics theory of social interaction, generalizing econometric discrete choice models. After showing the formal equivalence linking econometric multinomial logit models to equilibrium statical mechanics, a multi-population generalization of the Curie-Weiss model for ferromagnets is considered as a starting point in developing a model capable of describing sudden shifts in aggregate human behaviour. Existence of the thermodynamic limit for the model is shown by an asymptotic sub-additivity method and factorization of correlation functions is proved almost everywhere. The exact solution of the model is provided in the thermodynamical limit by finding converging upper and lower bounds for the system's pressure, and the solution is used to prove an analytic result regarding the number of possible equilibrium states of a two-population system. The work stresses the importance of linking regimes predicted by the model to real phenomena, and to this end it proposes two possible procedures to estimate the model's parameters starting from micro-level data. These are applied to three case studies based on census type data: though these studies are found to be ultimately inconclusive on an empirical level, considerations are drawn that encourage further refinements of the chosen modelling approach.
Engineering Glass Passivation Layers -Model Results
Energy Technology Data Exchange (ETDEWEB)
Skorski, Daniel C.; Ryan, Joseph V.; Strachan, Denis M.; Lepry, William C.
2011-08-08
The immobilization of radioactive waste into glass waste forms is a baseline process of nuclear waste management not only in the United States, but worldwide. The rate of radionuclide release from these glasses is a critical measure of the quality of the waste form. Over long-term tests and using extrapolations of ancient analogues, it has been shown that well designed glasses exhibit a dissolution rate that quickly decreases to a slow residual rate for the lifetime of the glass. The mechanistic cause of this decreased corrosion rate is a subject of debate, with one of the major theories suggesting that the decrease is caused by the formation of corrosion products in such a manner as to present a diffusion barrier on the surface of the glass. Although there is much evidence of this type of mechanism, there has been no attempt to engineer the effect to maximize the passivating qualities of the corrosion products. This study represents the first attempt to engineer the creation of passivating phases on the surface of glasses. Our approach utilizes interactions between the dissolving glass and elements from the disposal environment to create impermeable capping layers. By drawing from other corrosion studies in areas where passivation layers have been successfully engineered to protect the bulk material, we present here a report on mineral phases that are likely have a morphological tendency to encrust the surface of the glass. Our modeling has focused on using the AFCI glass system in a carbonate, sulfate, and phosphate rich environment. We evaluate the minerals predicted to form to determine the likelihood of the formation of a protective layer on the surface of the glass. We have also modeled individual ions in solutions vs. pH and the addition of aluminum and silicon. These results allow us to understand the pH and ion concentration dependence of mineral formation. We have determined that iron minerals are likely to form a complete incrustation layer and we plan
MERGING DIGITAL SURFACE MODELS IMPLEMENTING BAYESIAN APPROACHES
Directory of Open Access Journals (Sweden)
H. Sadeq
2016-06-01
Full Text Available In this research different DSMs from different sources have been merged. The merging is based on a probabilistic model using a Bayesian Approach. The implemented data have been sourced from very high resolution satellite imagery sensors (e.g. WorldView-1 and Pleiades. It is deemed preferable to use a Bayesian Approach when the data obtained from the sensors are limited and it is difficult to obtain many measurements or it would be very costly, thus the problem of the lack of data can be solved by introducing a priori estimations of data. To infer the prior data, it is assumed that the roofs of the buildings are specified as smooth, and for that purpose local entropy has been implemented. In addition to the a priori estimations, GNSS RTK measurements have been collected in the field which are used as check points to assess the quality of the DSMs and to validate the merging result. The model has been applied in the West-End of Glasgow containing different kinds of buildings, such as flat roofed and hipped roofed buildings. Both quantitative and qualitative methods have been employed to validate the merged DSM. The validation results have shown that the model was successfully able to improve the quality of the DSMs and improving some characteristics such as the roof surfaces, which consequently led to better representations. In addition to that, the developed model has been compared with the well established Maximum Likelihood model and showed similar quantitative statistical results and better qualitative results. Although the proposed model has been applied on DSMs that were derived from satellite imagery, it can be applied to any other sourced DSMs.
Appraisal of geodynamic inversion results: a data mining approach
Baumann, T. S.
2016-11-01
Bayesian sampling based inversions require many thousands or even millions of forward models, depending on how nonlinear or non-unique the inverse problem is, and how many unknowns are involved. The result of such a probabilistic inversion is not a single `best-fit' model, but rather a probability distribution that is represented by the entire model ensemble. Often, a geophysical inverse problem is non-unique, and the corresponding posterior distribution is multimodal, meaning that the distribution consists of clusters with similar models that represent the observations equally well. In these cases, we would like to visualize the characteristic model properties within each of these clusters of models. However, even for a moderate number of inversion parameters, a manual appraisal for a large number of models is not feasible. This poses the question whether it is possible to extract end-member models that represent each of the best-fit regions including their uncertainties. Here, I show how a machine learning tool can be used to characterize end-member models, including their uncertainties, from a complete model ensemble that represents a posterior probability distribution. The model ensemble used here results from a nonlinear geodynamic inverse problem, where rheological properties of the lithosphere are constrained from multiple geophysical observations. It is demonstrated that by taking vertical cross-sections through the effective viscosity structure of each of the models, the entire model ensemble can be classified into four end-member model categories that have a similar effective viscosity structure. These classification results are helpful to explore the non-uniqueness of the inverse problem and can be used to compute representative data fits for each of the end-member models. Conversely, these insights also reveal how new observational constraints could reduce the non-uniqueness. The method is not limited to geodynamic applications and a generalized MATLAB
Fusion via transpsoas lateral approach: considerations and initial results
Directory of Open Access Journals (Sweden)
Daniel de Abreu Oliveira
2014-09-01
Full Text Available OBJECTIVE: To present some technical considerations about interbody fusion by direct lateral retroperitoneal transpsoas approach and its initial results. METHODS: Non-randomized prospective study of 14 patients undergoing interbody fusion via lateral approach, with evaluation of initial results and complications. RESULTS: We collected and analyzed data from 14 patients with a total of 27 levels operated. The average operative time was 146 minutes and blood loss was on average less than 50 ml. Ten patients required supplemental percutaneous fixation with pedicle screws. VAS scores for the lumbar region and lower limbs and ODI had significant improvement in the postoperative period. There was an associated case of postoperative infection and thromboembolism that required reoperations. CONCLUSION: This technique has revolutionized the care of patients requiring fusion of T6-7 to L4-5. Following the five basic steps and using intraoperative monitoring, this technique is safe and reproducible with encouraging clinical results and low rate of serious complications.
Accelerated esthetic dental results using an interdisciplinary approach.
Spath, Andrew
2013-02-01
Traditionally, achieving case acceptance in situations that involve orthodontics has been challenging for clinicians, especially among adult male patients. In recent years, surgically accelerated orthodontics has emerged as an alternative approach for patients who might otherwise avoid treatment or choose a compromised form of treatment due to esthetic concerns about wearing traditional braces. In this case report, use of an interdisciplinary approach that combined Kois diagnostic principles with Accelerated Osteogenic Orthodontics (AOO) and lingual braces resulted in a successful restoration while maintaining satisfactory esthetics during treatment.
Results of steel containment vessel model test
International Nuclear Information System (INIS)
Luk, V.K.; Ludwigsen, J.S.; Hessheimer, M.F.; Komine, Kuniaki; Matsumoto, Tomoyuki; Costello, J.F.
1998-05-01
A series of static overpressurization tests of scale models of nuclear containment structures is being conducted by Sandia National Laboratories for the Nuclear Power Engineering Corporation of Japan and the US Nuclear Regulatory Commission. Two tests are being conducted: (1) a test of a model of a steel containment vessel (SCV) and (2) a test of a model of a prestressed concrete containment vessel (PCCV). This paper summarizes the conduct of the high pressure pneumatic test of the SCV model and the results of that test. Results of this test are summarized and are compared with pretest predictions performed by the sponsoring organizations and others who participated in a blind pretest prediction effort. Questions raised by this comparison are identified and plans for posttest analysis are discussed
modeling, observation and control, a multi-model approach
Elkhalil, Mansoura
2011-01-01
This thesis is devoted to the control of systems which dynamics can be suitably described by a multimodel approach from an investigation study of a model reference adaptative control performance enhancement. Four multimodel control approaches have been proposed. The first approach is based on an output reference model control design. A successful experimental validation involving a chemical reactor has been carried out. The second approach is based on a suitable partial state model reference ...
A physiological production model for cacao : results of model simulations
Zuidema, P.A.; Leffelaar, P.A.
2002-01-01
CASE2 is a physiological model for cocoa (Theobroma cacao L.) growth and yield. This report introduces the CAcao Simulation Engine for water-limited production in a non-technical way and presents simulation results obtained with the model.
Global energy modeling - A biophysical approach
Energy Technology Data Exchange (ETDEWEB)
Dale, Michael
2010-09-15
This paper contrasts the standard economic approach to energy modelling with energy models using a biophysical approach. Neither of these approaches includes changing energy-returns-on-investment (EROI) due to declining resource quality or the capital intensive nature of renewable energy sources. Both of these factors will become increasingly important in the future. An extension to the biophysical approach is outlined which encompasses a dynamic EROI function that explicitly incorporates technological learning. The model is used to explore several scenarios of long-term future energy supply especially concerning the global transition to renewable energy sources in the quest for a sustainable energy system.
Learning Actions Models: Qualitative Approach
DEFF Research Database (Denmark)
Bolander, Thomas; Gierasimczuk, Nina
2015-01-01
—they are identifiable in the limit.We then move on to a particular learning method, which proceeds via restriction of a space of events within a learning-specific action model. This way of learning closely resembles the well-known update method from dynamic epistemic logic. We introduce several different learning...... identifiability (conclusively inferring the appropriate action model in finite time) and identifiability in the limit (inconclusive convergence to the right action model). We show that deterministic actions are finitely identifiable, while non-deterministic actions require more learning power...... methods suited for finite identifiability of particular types of deterministic actions....
Interpreting Results from the Multinomial Logit Model
DEFF Research Database (Denmark)
Wulff, Jesper
2015-01-01
This article provides guidelines and illustrates practical steps necessary for an analysis of results from the multinomial logit model (MLM). The MLM is a popular model in the strategy literature because it allows researchers to examine strategic choices with multiple outcomes. However, there seem...... to be systematic issues with regard to how researchers interpret their results when using the MLM. In this study, I present a set of guidelines critical to analyzing and interpreting results from the MLM. The procedure involves intuitive graphical representations of predicted probabilities and marginal effects...... suitable for both interpretation and communication of results. The pratical steps are illustrated through an application of the MLM to the choice of foreign market entry mode....
A Unified Approach to Modeling and Programming
DEFF Research Database (Denmark)
Madsen, Ole Lehrmann; Møller-Pedersen, Birger
2010-01-01
of this paper is to go back to the future and get inspiration from SIMULA and propose a unied approach. In addition to reintroducing the contributions of SIMULA and the Scandinavian approach to object-oriented programming, we do this by discussing a number of issues in modeling and programming and argue3 why we......SIMULA was a language for modeling and programming and provided a unied approach to modeling and programming in contrast to methodologies based on structured analysis and design. The current development seems to be going in the direction of separation of modeling and programming. The goal...
A Modeling Approach for Marine Observatory
Directory of Open Access Journals (Sweden)
Charbel Geryes Aoun
2015-02-01
Full Text Available Infrastructure of Marine Observatory (MO is an UnderWater Sensor Networks (UW-SN to perform collaborative monitoring tasks over a given area. This observation should take into consideration the environmental constraints since it may require specific tools, materials and devices (cables, servers, etc.. The logical and physical components that are used in these observatories provide data exchanged between the various devices of the environment (Smart Sensor, Data Fusion. These components provide new functionalities or services due to the long period running of the network. In this paper, we present our approach in extending the modeling languages to include new domain- specific concepts and constraints. Thus, we propose a meta-model that is used to generate a new design tool (ArchiMO. We illustrate our proposal with an example from the MO domain on object localization with several acoustics sensors. Additionally, we generate the corresponding simulation code for a standard network simulator using our self-developed domain-specific model compiler. Our approach helps to reduce the complexity and time of the design activity of a Marine Observatory. It provides a way to share the different viewpoints of the designers in the MO domain and obtain simulation results to estimate the network capabilities.
A physical approach to protein structure prediction: CASP4 results
Energy Technology Data Exchange (ETDEWEB)
Crivelli, Silvia; Eskow, Elizabeth; Bader, Brett; Lamberti, Vincent; Byrd, Richard; Schnabel, Robert; Head-Gordon, Teresa
2001-02-27
We describe our global optimization method called Stochastic Perturbation with Soft Constraints (SPSC), which uses information from known proteins to predict secondary structure, but not in the tertiary structure predictions or in generating the terms of the physics-based energy function. Our approach is also characterized by the use of an all atom energy function that includes a novel hydrophobic solvation function derived from experiments that shows promising ability for energy discrimination against misfolded structures. We present the results obtained using our SPSC method and energy function for blind prediction in the 4th Critical Assessment of Techniques for Protein Structure Prediction (CASP4) competition, and show that our approach is more effective on targets for which less information from known proteins is available. In fact our SPSC method produced the best prediction for one of the most difficult targets of the competition, a new fold protein of 240 amino acids.
Szekeres models: a covariant approach
Apostolopoulos, Pantelis S.
2017-05-01
We exploit the 1 + 1 + 2 formalism to covariantly describe the inhomogeneous and anisotropic Szekeres models. It is shown that an average scale length can be defined covariantly which satisfies a 2d equation of motion driven from the effective gravitational mass (EGM) contained in the dust cloud. The contributions to the EGM are encoded to the energy density of the dust fluid and the free gravitational field E ab . We show that the quasi-symmetric property of the Szekeres models is justified through the existence of 3 independent intrinsic Killing vector fields (IKVFs). In addition the notions of the apparent and absolute apparent horizons are briefly discussed and we give an alternative gauge-invariant form to define them in terms of the kinematical variables of the spacelike congruences. We argue that the proposed program can be used in order to express Sachs’ optical equations in a covariant form and analyze the confrontation of a spatially inhomogeneous irrotational overdense fluid model with the observational data.
Multiple Model Approaches to Modelling and Control,
DEFF Research Database (Denmark)
appeal in building systems which operate robustly over a wide range of operating conditions by decomposing them into a number of simplerlinear modelling or control problems, even for nonlinear modelling or control problems. This appeal has been a factor in the development of increasinglypopular `local...... to problems in the process industries, biomedical applications and autonomoussystems. The successful application of the ideas to demanding problems is already encouraging, but creative development of the basic framework isneeded to better allow the integration of human knowledge with automated learning....... The underlying question is `How should we partition the system - what is `local'?'. This book presents alternative ways of bringing submodels together,which lead to varying levels of performance and insight. Some are further developed for autonomous learning of parameters from data, while others havefocused...
Modeling software behavior a craftsman's approach
Jorgensen, Paul C
2009-01-01
A common problem with most texts on requirements specifications is that they emphasize structural models to the near exclusion of behavioral models-focusing on what the software is, rather than what it does. If they do cover behavioral models, the coverage is brief and usually focused on a single model. Modeling Software Behavior: A Craftsman's Approach provides detailed treatment of various models of software behavior that support early analysis, comprehension, and model-based testing. Based on the popular and continually evolving course on requirements specification models taught by the auth
A multiscale approach for modeling atherosclerosis progression.
Exarchos, Konstantinos P; Carpegianni, Clara; Rigas, Georgios; Exarchos, Themis P; Vozzi, Federico; Sakellarios, Antonis; Marraccini, Paolo; Naka, Katerina; Michalis, Lambros; Parodi, Oberdan; Fotiadis, Dimitrios I
2015-03-01
Progression of atherosclerotic process constitutes a serious and quite common condition due to accumulation of fatty materials in the arterial wall, consequently posing serious cardiovascular complications. In this paper, we assemble and analyze a multitude of heterogeneous data in order to model the progression of atherosclerosis (ATS) in coronary vessels. The patient's medical record, biochemical analytes, monocyte information, adhesion molecules, and therapy-related data comprise the input for the subsequent analysis. As indicator of coronary lesion progression, two consecutive coronary computed tomography angiographies have been evaluated in the same patient. To this end, a set of 39 patients is studied using a twofold approach, namely, baseline analysis and temporal analysis. The former approach employs baseline information in order to predict the future state of the patient (in terms of progression of ATS). The latter is based on an approach encompassing dynamic Bayesian networks whereby snapshots of the patient's status over the follow-up are analyzed in order to model the evolvement of ATS, taking into account the temporal dimension of the disease. The quantitative assessment of our work has resulted in 93.3% accuracy for the case of baseline analysis, and 83% overall accuracy for the temporal analysis, in terms of modeling and predicting the evolvement of ATS. It should be noted that the application of the SMOTE algorithm for handling class imbalance and the subsequent evaluation procedure might have introduced an overestimation of the performance metrics, due to the employment of synthesized instances. The most prominent features found to play a substantial role in the progression of the disease are: diabetes, cholesterol and cholesterol/HDL. Among novel markers, the CD11b marker of leukocyte integrin complex is associated with coronary plaque progression.
Current approaches to gene regulatory network modelling
Directory of Open Access Journals (Sweden)
Brazma Alvis
2007-09-01
Full Text Available Abstract Many different approaches have been developed to model and simulate gene regulatory networks. We proposed the following categories for gene regulatory network models: network parts lists, network topology models, network control logic models, and dynamic models. Here we will describe some examples for each of these categories. We will study the topology of gene regulatory networks in yeast in more detail, comparing a direct network derived from transcription factor binding data and an indirect network derived from genome-wide expression data in mutants. Regarding the network dynamics we briefly describe discrete and continuous approaches to network modelling, then describe a hybrid model called Finite State Linear Model and demonstrate that some simple network dynamics can be simulated in this model.
Distributed simulation a model driven engineering approach
Topçu, Okan; Oğuztüzün, Halit; Yilmaz, Levent
2016-01-01
Backed by substantive case studies, the novel approach to software engineering for distributed simulation outlined in this text demonstrates the potent synergies between model-driven techniques, simulation, intelligent agents, and computer systems development.
THE RESULTS OF PROFESSIONAL APPROACH AND INCREASED INTENSITY OF WORK
Directory of Open Access Journals (Sweden)
Georgi Georgiev
2014-06-01
Full Text Available Introduction: The goal of the research is to establish if the professional approach and increased intensity of applied results in improvements and differences between the functional and motoric abilities (skills and habits with students. Methods: The research has been conducted on a sample of 76 students at the age of 14. The first subsample consists of 40 students, and the second of 36 students, who, along with their regular school classes of 3 times a week and additional sports subject as choice (this refers to the first subsample as well, had regular trainings in basketball clubs three hours a week. They were tested by three indexes: 1 motoric abilities; 2 motoric skills and habits (Majeric, 2004; and 3 functional abilities (Jovanovic, 1999. There were calculated: basic descriptive statistic parameters, t-tests of independent samples, analysis of variance and Friedman test (Bala, 1986. Results: The results of the analyses are represented in 8 tables. On the base of the obtained results, the conclusion is that better results in all three indexes, are determined with the second subsample. It is those who are involved in regular school classes, have the sport as their additional subject choice, and had an active training work in their sports clubs. Discussion: The authors general conclusion of the research is that the number of that kind of research approach is quite small The results of the analyses of the first index in the conducted research show great similarity with the results obtained in the research of Georgiev, Kostovski, & Mitrevski (2012. The results of the second index indicate great similarity with Mitrevski’s research (2012. The results of the third index are logically sustained. They are better with the second subsample. References: Bala G (1986. Logicke osnove metoda za analizu podataka iz istrazivanja u fizickoj kulturi. Novi Sad, Sava Muncan. Georgiev G, Kostovski Z, Mitrevski V (2012. Sport Mont, 34-36, 105-9. Jovanovic G
Validation of Modeling Flow Approaching Navigation Locks
2013-08-01
USACE, Pittsburgh District ( LRP ) requested that the US Army Engineer Research and Development Center, Coastal and ERDC/CHL TR-13-9 2 Hydraulics...approaching the lock and dam. The second set of experiments considered a design, referred to as Plan B lock approach, which contained the weir field in...conditions and model parameters A discharge of 1.35 cfs was set as the inflow boundary condition at the upstream end of the model. The outflow boundary was
The Danish national passenger model – Model specification and results
DEFF Research Database (Denmark)
Rich, Jeppe; Hansen, Christian Overgaard
2016-01-01
, the paper provides a description of a large-scale forecast model with a discussion of the linkage between population synthesis, demand and assignment. Secondly, the paper gives specific attention to model specification and in particular choice of functional form and cost-damping. Specifically we suggest...... a family of logarithmic spline functions and illustrate how it is applied in the model. Thirdly and finally, we evaluate model sensitivity and performance by evaluating the distance distribution and elasticities. In the paper we present results where the spline-function is compared with more traditional...... function types and it is indicated that the spline-function provides a better description of the data. Results are also provided in the form of a back-casting exercise where the model is tested in a back-casting scenario to 2002....
Scale Model Thruster Acoustic Measurement Results
Vargas, Magda; Kenny, R. Jeremy
2013-01-01
The Space Launch System (SLS) Scale Model Acoustic Test (SMAT) is a 5% scale representation of the SLS vehicle, mobile launcher, tower, and launch pad trench. The SLS launch propulsion system will be comprised of the Rocket Assisted Take-Off (RATO) motors representing the solid boosters and 4 Gas Hydrogen (GH2) thrusters representing the core engines. The GH2 thrusters were tested in a horizontal configuration in order to characterize their performance. In Phase 1, a single thruster was fired to determine the engine performance parameters necessary for scaling a single engine. A cluster configuration, consisting of the 4 thrusters, was tested in Phase 2 to integrate the system and determine their combined performance. Acoustic and overpressure data was collected during both test phases in order to characterize the system's acoustic performance. The results from the single thruster and 4- thuster system are discussed and compared.
CMS standard model Higgs boson results
Directory of Open Access Journals (Sweden)
Garcia-Abia Pablo
2013-11-01
Full Text Available In July 2012 CMS announced the discovery of a new boson with properties resembling those of the long-sought Higgs boson. The analysis of the proton-proton collision data recorded by the CMS detector at the LHC, corresponding to integrated luminosities of 5.1 fb−1 at √s = 7 TeV and 19.6 fb−1 at √s = 8 TeV, confirm the Higgs-like nature of the new boson, with a signal strength associated with vector bosons and fermions consistent with the expectations for a standard model (SM Higgs boson, and spin-parity clearly favouring the scalar nature of the new boson. In this note I review the updated results of the CMS experiment.
Risk Modelling for Passages in Approach Channel
Directory of Open Access Journals (Sweden)
Leszek Smolarek
2013-01-01
Full Text Available Methods of multivariate statistics, stochastic processes, and simulation methods are used to identify and assess the risk measures. This paper presents the use of generalized linear models and Markov models to study risks to ships along the approach channel. These models combined with simulation testing are used to determine the time required for continuous monitoring of endangered objects or period at which the level of risk should be verified.
A new approach to modeling aviation accidents
Rao, Arjun Harsha
views aviation accidents as a set of hazardous states of a system (pilot and aircraft), and triggers that cause the system to move between hazardous states. I used the NTSB's accident coding manual (that contains nearly 4000 different codes) to develop a "dictionary" of hazardous states, triggers, and information codes. Then, I created the "grammar", or a set of rules, that: (1) orders the hazardous states in each accident; and, (2) links the hazardous states using the appropriate triggers. This approach: (1) provides a more correct count of the causes for accidents in the NTSB database; and, (2) checks for gaps or omissions in NTSB accident data, and fills in some of these gaps using logic-based rules. These rules also help identify and count causes for accidents that were not discernable from previous analyses of historical accident data. I apply the model to 6200 helicopter accidents that occurred in the US between 1982 and 2015. First, I identify the states and triggers that are most likely to be associated with fatal and non-fatal accidents. The results suggest that non-fatal accidents, which account for approximately 84% of the accidents, provide valuable opportunities to learn about the causes for accidents. Next, I investigate the causes of inflight loss of control using both a conventional approach and using the state-based approach. The conventional analysis provides little insight into the causal mechanism for LOC. For instance, the top cause of LOC is "aircraft control/directional control not maintained", which does not provide any insight. In contrast, the state-based analysis showed that pilots' tendency to clip objects frequently triggered LOC (16.7% of LOC accidents)--this finding was not directly discernable from conventional analyses. Finally, I investigate the causes for improper autorotations using both a conventional approach and the state-based approach. The conventional approach uses modifiers (e.g., "improper", "misjudged") associated with "24520
McGurk, B. J.; Painter, T. H.
2014-12-01
Deterministic snow accumulation and ablation simulation models are widely used by runoff managers throughout the world to predict runoff quantities and timing. Model fitting is typically based on matching modeled runoff volumes and timing with observed flow time series at a few points in the basin. In recent decades, sparse networks of point measurements of the mountain snowpacks have been available to compare with modeled snowpack, but the comparability of results from a snow sensor or course to model polygons of 5 to 50 sq. km is suspect. However, snowpack extent, depth, and derived snow water equivalent have been produced by the NASA/JPL Airborne Snow Observatory (ASO) mission for spring of 20013 and 2014 in the Tuolumne River basin above Hetch Hetchy Reservoir. These high-resolution snowpack data have exposed the weakness in a model calibration based on runoff alone. The U.S. Geological Survey's Precipitation Runoff Modeling System (PRMS) calibration that was based on 30-years of inflow to Hetch Hetchy produces reasonable inflow results, but modeled spatial snowpack location and water quantity diverged significantly from the weekly measurements made by ASO during the two ablation seasons. The reason is that the PRMS model has many flow paths, storages, and water transfer equations, and a calibrated outflow time series can be right for many wrong reasons. The addition of a detailed knowledge of snow extent and water content constrains the model so that it is a better representation of the actual watershed hydrology. The mechanics of recalibrating PRMS to the ASO measurements will be described, and comparisons in observed versus modeled flow for both a small subbasin and the entire Hetch Hetchy basin will be shown. The recalibrated model provided a bitter fit to the snowmelt recession, a key factor for water managers as they balance declining inflows with demand for power generation and ecosystem releases during the final months of snow melt runoff.
ECOMOD - An ecological approach to radioecological modelling
International Nuclear Information System (INIS)
Sazykina, Tatiana G.
2000-01-01
A unified methodology is proposed to simulate the dynamic processes of radionuclide migration in aquatic food chains in parallel with their stable analogue elements. The distinguishing feature of the unified radioecological/ecological approach is the description of radionuclide migration along with dynamic equations for the ecosystem. The ability of the methodology to predict the results of radioecological experiments is demonstrated by an example of radionuclide (iron group) accumulation by a laboratory culture of the algae Platymonas viridis. Based on the unified methodology, the 'ECOMOD' radioecological model was developed to simulate dynamic radioecological processes in aquatic ecosystems. It comprises three basic modules, which are operated as a set of inter-related programs. The 'ECOSYSTEM' module solves non-linear ecological equations, describing the biomass dynamics of essential ecosystem components. The 'RADIONUCLIDE DISTRIBUTION' module calculates the radionuclide distribution in abiotic and biotic components of the aquatic ecosystem. The 'DOSE ASSESSMENT' module calculates doses to aquatic biota and doses to man from aquatic food chains. The application of the ECOMOD model to reconstruct the radionuclide distribution in the Chernobyl Cooling Pond ecosystem in the early period after the accident shows good agreement with observations
Immersive visualization of dynamic CFD model results
International Nuclear Information System (INIS)
Comparato, J.R.; Ringel, K.L.; Heath, D.J.
2004-01-01
With immersive visualization the engineer has the means for vividly understanding problem causes and discovering opportunities to improve design. Software can generate an interactive world in which collaborators experience the results of complex mathematical simulations such as computational fluid dynamic (CFD) modeling. Such software, while providing unique benefits over traditional visualization techniques, presents special development challenges. The visualization of large quantities of data interactively requires both significant computational power and shrewd data management. On the computational front, commodity hardware is outperforming large workstations in graphical quality and frame rates. Also, 64-bit commodity computing shows promise in enabling interactive visualization of large datasets. Initial interactive transient visualization methods and examples are presented, as well as development trends in commodity hardware and clustering. Interactive, immersive visualization relies on relevant data being stored in active memory for fast response to user requests. For large or transient datasets, data management becomes a key issue. Techniques for dynamic data loading and data reduction are presented as means to increase visualization performance. (author)
Linkage of PRA models. Phase 1, Results
Energy Technology Data Exchange (ETDEWEB)
Smith, C.L.; Knudsen, J.K.; Kelly, D.L.
1995-12-01
The goal of the Phase I work of the ``Linkage of PRA Models`` project was to postulate methods of providing guidance for US Nuclear Regulator Commission (NRC) personnel on the selection and usage of probabilistic risk assessment (PRA) models that are best suited to the analysis they are performing. In particular, methods and associated features are provided for (a) the selection of an appropriate PRA model for a particular analysis, (b) complementary evaluation tools for the analysis, and (c) a PRA model cross-referencing method. As part of this work, three areas adjoining ``linking`` analyses to PRA models were investigated: (a) the PRA models that are currently available, (b) the various types of analyses that are performed within the NRC, and (c) the difficulty in trying to provide a ``generic`` classification scheme to groups plants based upon a particular plant attribute.
SLS Navigation Model-Based Design Approach
Oliver, T. Emerson; Anzalone, Evan; Geohagan, Kevin; Bernard, Bill; Park, Thomas
2018-01-01
The SLS Program chose to implement a Model-based Design and Model-based Requirements approach for managing component design information and system requirements. This approach differs from previous large-scale design efforts at Marshall Space Flight Center where design documentation alone conveyed information required for vehicle design and analysis and where extensive requirements sets were used to scope and constrain the design. The SLS Navigation Team has been responsible for the Program-controlled Design Math Models (DMMs) which describe and represent the performance of the Inertial Navigation System (INS) and the Rate Gyro Assemblies (RGAs) used by Guidance, Navigation, and Controls (GN&C). The SLS Navigation Team is also responsible for the navigation algorithms. The navigation algorithms are delivered for implementation on the flight hardware as a DMM. For the SLS Block 1-B design, the additional GPS Receiver hardware is managed as a DMM at the vehicle design level. This paper provides a discussion of the processes and methods used to engineer, design, and coordinate engineering trades and performance assessments using SLS practices as applied to the GN&C system, with a particular focus on the Navigation components. These include composing system requirements, requirements verification, model development, model verification and validation, and modeling and analysis approaches. The Model-based Design and Requirements approach does not reduce the effort associated with the design process versus previous processes used at Marshall Space Flight Center. Instead, the approach takes advantage of overlap between the requirements development and management process, and the design and analysis process by efficiently combining the control (i.e. the requirement) and the design mechanisms. The design mechanism is the representation of the component behavior and performance in design and analysis tools. The focus in the early design process shifts from the development and
Modeling and Field Results from Seismic Stimulation
International Nuclear Information System (INIS)
Majer, E.; Pride, S.; Lo, W.; Daley, T.; Nakagawa, Seiji; Sposito, Garrison; Roberts, P.
2006-01-01
Modeling the effect of seismic stimulation employing Maxwell-Boltzmann theory shows that the important component of stimulation is mechanical rather than fluid pressure effects. Modeling using Biot theory (two phases) shows that the pressure effects diffuse too quickly to be of practical significance. Field data from actual stimulation will be shown to compare to theory
A Conceptual Modeling Approach for OLAP Personalization
Garrigós, Irene; Pardillo, Jesús; Mazón, Jose-Norberto; Trujillo, Juan
Data warehouses rely on multidimensional models in order to provide decision makers with appropriate structures to intuitively analyze data with OLAP technologies. However, data warehouses may be potentially large and multidimensional structures become increasingly complex to be understood at a glance. Even if a departmental data warehouse (also known as data mart) is used, these structures would be also too complex. As a consequence, acquiring the required information is more costly than expected and decision makers using OLAP tools may get frustrated. In this context, current approaches for data warehouse design are focused on deriving a unique OLAP schema for all analysts from their previously stated information requirements, which is not enough to lighten the complexity of the decision making process. To overcome this drawback, we argue for personalizing multidimensional models for OLAP technologies according to the continuously changing user characteristics, context, requirements and behaviour. In this paper, we present a novel approach to personalizing OLAP systems at the conceptual level based on the underlying multidimensional model of the data warehouse, a user model and a set of personalization rules. The great advantage of our approach is that a personalized OLAP schema is provided for each decision maker contributing to better satisfy their specific analysis needs. Finally, we show the applicability of our approach through a sample scenario based on our CASE tool for data warehouse development.
Surfleet, Christopher G.; Tullos, Desirèe; Chang, Heejun; Jung, Il-Won
2012-09-01
SummaryA wide variety of approaches to hydrologic (rainfall-runoff) modeling of river basins confounds our ability to select, develop, and interpret models, particularly in the evaluation of prediction uncertainty associated with climate change assessment. To inform the model selection process, we characterized and compared three structurally-distinct approaches and spatial scales of parameterization to modeling catchment hydrology: a large-scale approach (using the VIC model; 671,000 km2 area), a basin-scale approach (using the PRMS model; 29,700 km2 area), and a site-specific approach (the GSFLOW model; 4700 km2 area) forced by the same future climate estimates. For each approach, we present measures of fit to historic observations and predictions of future response, as well as estimates of model parameter uncertainty, when available. While the site-specific approach generally had the best fit to historic measurements, the performance of the model approaches varied. The site-specific approach generated the best fit at unregulated sites, the large scale approach performed best just downstream of flood control projects, and model performance varied at the farthest downstream sites where streamflow regulation is mitigated to some extent by unregulated tributaries and water diversions. These results illustrate how selection of a modeling approach and interpretation of climate change projections require (a) appropriate parameterization of the models for climate and hydrologic processes governing runoff generation in the area under study, (b) understanding and justifying the assumptions and limitations of the model, and (c) estimates of uncertainty associated with the modeling approach.
Heat transfer modeling an inductive approach
Sidebotham, George
2015-01-01
This innovative text emphasizes a "less-is-more" approach to modeling complicated systems such as heat transfer by treating them first as "1-node lumped models" that yield simple closed-form solutions. The author develops numerical techniques for students to obtain more detail, but also trains them to use the techniques only when simpler approaches fail. Covering all essential methods offered in traditional texts, but with a different order, Professor Sidebotham stresses inductive thinking and problem solving as well as a constructive understanding of modern, computer-based practice. Readers learn to develop their own code in the context of the material, rather than just how to use packaged software, offering a deeper, intrinsic grasp behind models of heat transfer. Developed from over twenty-five years of lecture notes to teach students of mechanical and chemical engineering at The Cooper Union for the Advancement of Science and Art, the book is ideal for students and practitioners across engineering discipl...
Coupled Michigan MHD - Rice Convection Model Results
de Zeeuw, D.; Sazykin, S.; Wolf, D.; Gombosi, T.; Powell, K.
2002-12-01
A new high performance Rice Convection Model (RCM) has been coupled to the adaptive-grid Michigan MHD model (BATSRUS). This fully coupled code allows us to self-consistently simulate the physics in the inner and middle magnetosphere. A study will be presented of the basic characteristics of the inner and middle magnetosphere in the context of a single coupled-code run for idealized storm inputs. The analysis will include region-2 currents, shielding of the inner magnetosphere, partial ring currents, pressure distribution, magnetic field inflation, and distribution of pV^gamma.
Graphical interpretation of numerical model results
International Nuclear Information System (INIS)
Drewes, D.R.
1979-01-01
Computer software has been developed to produce high quality graphical displays of data from a numerical grid model. The code uses an existing graphical display package (DISSPLA) and overcomes some of the problems of both line-printer output and traditional graphics. The software has been designed to be flexible enough to handle arbitrarily placed computation grids and a variety of display requirements
Quasirelativistic quark model in quasipotential approach
Matveev, V A; Savrin, V I; Sissakian, A N
2002-01-01
The relativistic particles interaction is described within the frames of quasipotential approach. The presentation is based on the so called covariant simultaneous formulation of the quantum field theory, where by the theory is considered on the spatial-like three-dimensional hypersurface in the Minkowski space. Special attention is paid to the methods of plotting various quasipotentials as well as to the applications of the quasipotential approach to describing the characteristics of the relativistic particles interaction in the quark models, namely: the hadrons elastic scattering amplitudes, the mass spectra and widths mesons decays, the cross sections of the deep inelastic leptons scattering on the hadrons
A new approach for developing adjoint models
Farrell, P. E.; Funke, S. W.
2011-12-01
Many data assimilation algorithms rely on the availability of gradients of misfit functionals, which can be efficiently computed with adjoint models. However, the development of an adjoint model for a complex geophysical code is generally very difficult. Algorithmic differentiation (AD, also called automatic differentiation) offers one strategy for simplifying this task: it takes the abstraction that a model is a sequence of primitive instructions, each of which may be differentiated in turn. While extremely successful, this low-level abstraction runs into time-consuming difficulties when applied to the whole codebase of a model, such as differentiating through linear solves, model I/O, calls to external libraries, language features that are unsupported by the AD tool, and the use of multiple programming languages. While these difficulties can be overcome, it requires a large amount of technical expertise and an intimate familiarity with both the AD tool and the model. An alternative to applying the AD tool to the whole codebase is to assemble the discrete adjoint equations and use these to compute the necessary gradients. With this approach, the AD tool must be applied to the nonlinear assembly operators, which are typically small, self-contained units of the codebase. The disadvantage of this approach is that the assembly of the discrete adjoint equations is still very difficult to perform correctly, especially for complex multiphysics models that perform temporal integration; as it stands, this approach is as difficult and time-consuming as applying AD to the whole model. In this work, we have developed a library which greatly simplifies and automates the alternate approach of assembling the discrete adjoint equations. We propose a complementary, higher-level abstraction to that of AD: that a model is a sequence of linear solves. The developer annotates model source code with library calls that build a 'tape' of the operators involved and their dependencies, and
Relationship Marketing results: proposition of a cognitive mapping model
Directory of Open Access Journals (Sweden)
Iná Futino Barreto
2015-12-01
Full Text Available Objective - This research sought to develop a cognitive model that expresses how marketing professionals understand the relationship between the constructs that define relationship marketing (RM. It also tried to understand, using the obtained model, how objectives in this field are achieved. Design/methodology/approach – Through cognitive mapping, we traced 35 individual mental maps, highlighting how each respondent understands the interactions between RM elements. Based on the views of these individuals, we established an aggregate mental map. Theoretical foundation – The topic is based on a literature review that explores the RM concept and its main elements. Based on this review, we listed eleven main constructs. Findings – We established an aggregate mental map that represents the RM structural model. Model analysis identified that CLV is understood as the final result of RM. We also observed that the impact of most of the RM elements on CLV is brokered by loyalty. Personalization and quality, on the other hand, proved to be process input elements, and are the ones that most strongly impact others. Finally, we highlight that elements that punish customers are much less effective than elements that benefit them. Contributions - The model was able to insert core elements of RM, but absent from most formal models: CLV and customization. The analysis allowed us to understand the interactions between the RM elements and how the end result of RM (CLV is formed. This understanding improves knowledge on the subject and helps guide, assess and correct actions.
Ignalina NPP Safety Analysis: Models and Results
International Nuclear Information System (INIS)
Uspuras, E.
1999-01-01
Research directions, linked to safety assessment of the Ignalina NPP, of the scientific safety analysis group are presented: Thermal-hydraulic analysis of accidents and operational transients; Thermal-hydraulic assessment of Ignalina NPP Accident Localization System and other compartments; Structural analysis of plant components, piping and other parts of Main Circulation Circuit; Assessment of RBMK-1500 reactor core and other. Models and main works carried out last year are described. (author)
Modeling clicks beyond the first result page
Chuklin, A.; Serdyukov, P.; de Rijke, M.
2013-01-01
Most modern web search engines yield a list of documents of a fixed length (usually 10) in response to a user query. The next ten search results are usually available in one click. These documents either replace the current result page or are appended to the end. Hence, in order to examine more
Dynamic Metabolic Model Building Based on the Ensemble Modeling Approach
Energy Technology Data Exchange (ETDEWEB)
Liao, James C. [Univ. of California, Los Angeles, CA (United States)
2016-10-01
Ensemble modeling of kinetic systems addresses the challenges of kinetic model construction, with respect to parameter value selection, and still allows for the rich insights possible from kinetic models. This project aimed to show that constructing, implementing, and analyzing such models is a useful tool for the metabolic engineering toolkit, and that they can result in actionable insights from models. Key concepts are developed and deliverable publications and results are presented.
Evolutionary modeling-based approach for model errors correction
Directory of Open Access Journals (Sweden)
S. Q. Wan
2012-08-01
Full Text Available The inverse problem of using the information of historical data to estimate model errors is one of the science frontier research topics. In this study, we investigate such a problem using the classic Lorenz (1963 equation as a prediction model and the Lorenz equation with a periodic evolutionary function as an accurate representation of reality to generate "observational data."
On the basis of the intelligent features of evolutionary modeling (EM, including self-organization, self-adaptive and self-learning, the dynamic information contained in the historical data can be identified and extracted by computer automatically. Thereby, a new approach is proposed to estimate model errors based on EM in the present paper. Numerical tests demonstrate the ability of the new approach to correct model structural errors. In fact, it can actualize the combination of the statistics and dynamics to certain extent.
Reusable Component Model Development Approach for Parallel and Distributed Simulation
Zhu, Feng; Yao, Yiping; Chen, Huilong; Yao, Feng
2014-01-01
Model reuse is a key issue to be resolved in parallel and distributed simulation at present. However, component models built by different domain experts usually have diversiform interfaces, couple tightly, and bind with simulation platforms closely. As a result, they are difficult to be reused across different simulation platforms and applications. To address the problem, this paper first proposed a reusable component model framework. Based on this framework, then our reusable model development approach is elaborated, which contains two phases: (1) domain experts create simulation computational modules observing three principles to achieve their independence; (2) model developer encapsulates these simulation computational modules with six standard service interfaces to improve their reusability. The case study of a radar model indicates that the model developed using our approach has good reusability and it is easy to be used in different simulation platforms and applications. PMID:24729751
Interfacial Fluid Mechanics A Mathematical Modeling Approach
Ajaev, Vladimir S
2012-01-01
Interfacial Fluid Mechanics: A Mathematical Modeling Approach provides an introduction to mathematical models of viscous flow used in rapidly developing fields of microfluidics and microscale heat transfer. The basic physical effects are first introduced in the context of simple configurations and their relative importance in typical microscale applications is discussed. Then,several configurations of importance to microfluidics, most notably thin films/droplets on substrates and confined bubbles, are discussed in detail. Topics from current research on electrokinetic phenomena, liquid flow near structured solid surfaces, evaporation/condensation, and surfactant phenomena are discussed in the later chapters. This book also: Discusses mathematical models in the context of actual applications such as electrowetting Includes unique material on fluid flow near structured surfaces and phase change phenomena Shows readers how to solve modeling problems related to microscale multiphase flows Interfacial Fluid Me...
Continuum modeling an approach through practical examples
Muntean, Adrian
2015-01-01
This book develops continuum modeling skills and approaches the topic from three sides: (1) derivation of global integral laws together with the associated local differential equations, (2) design of constitutive laws and (3) modeling boundary processes. The focus of this presentation lies on many practical examples covering aspects such as coupled flow, diffusion and reaction in porous media or microwave heating of a pizza, as well as traffic issues in bacterial colonies and energy harvesting from geothermal wells. The target audience comprises primarily graduate students in pure and applied mathematics as well as working practitioners in engineering who are faced by nonstandard rheological topics like those typically arising in the food industry.
Some results on hyperscaling in the 3D Ising model
Energy Technology Data Exchange (ETDEWEB)
Baker, G.A. Jr. [Los Alamos National Lab., NM (United States). Theoretical Div.; Kawashima, Naoki [Univ. of Tokyo (Japan). Dept. of Physics
1995-09-01
The authors review exact studies on finite-sized 2 dimensional Ising models and show that the point for an infinite-sized model at the critical temperature is a point of nonuniform approach in the temperature-size plane. They also illuminate some strong effects of finite-size on quantities which do not diverge at the critical point. They then review Monte Carlo studies for 3 dimensional Ising models of various sizes (L = 2--100) at various temperatures. From these results they find that the data for the renormalized coupling constant collapses nicely when plotted against the correlation length, determined in a system of edge length L, divided by L. They also find that {zeta}{sub L}/L {ge} 0.26 is definitely too large for reliable studies of the critical value, g*, of the renormalized coupling constant. They have reasonable evidence that {zeta}{sub L}/L {approx} 0.1 is adequate for results that are within one percent of those for the infinite system size. On this basis, they have conducted a series of Monte Carlo calculations with this condition imposed. These calculations were made practical by the development of improved estimators for use in the Swendsen-Wang cluster method. The authors found from these results, coupled with a reversed limit computation (size increases with the temperature fixed at the critical temperature), that g* > 0, although there may well be a sharp downward drop in g as the critical temperature is approached in accord with the predictions of series analysis. The results support the validity of hyperscaling in the 3 dimensional Ising model.
Microplasticity of MMC. Experimental results and modelling
Energy Technology Data Exchange (ETDEWEB)
Maire, E. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Lormand, G. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Gobin, P.F. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Fougeres, R. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France))
1993-11-01
The microplastic behavior of several MMC is investigated by means of tension and compression tests. This behavior is assymetric : the proportional limit is higher in tension than in compression but the work hardening rate is higher in compression. These differences are analysed in terms of maxium of the Tresca's shear stress at the interface (proportional limit) and of the emission of dislocation loops during the cooling (work hardening rate). On another hand, a model is proposed to calculate the value of the yield stress, describing the composite as a material composed of three phases : inclusion, unaffected matrix and matrix surrounding the inclusion having a gradient in the density of the thermally induced dilocations. (orig.).
Mapping and Analyzing Acoustic Surveys' Results: A GIS Approach
National Research Council Canada - National Science Library
Manghi, Michele
2001-01-01
... to provide one general clear picture of the study area. Nowadays, more than expanding scientific knowledge about acoustic communication and echolocation in marine mammals, researchers' interest is shifting to more comprehensive research topics. The methodology used to consolidate on a GIS acoustic data, historical data and measured or modeled parameters is hereafter described.
Datamining approaches for modeling tumor control probability.
Naqa, Issam El; Deasy, Joseph O; Mu, Yi; Huang, Ellen; Hope, Andrew J; Lindsay, Patricia E; Apte, Aditya; Alaly, James; Bradley, Jeffrey D
2010-11-01
Tumor control probability (TCP) to radiotherapy is determined by complex interactions between tumor biology, tumor microenvironment, radiation dosimetry, and patient-related variables. The complexity of these heterogeneous variable interactions constitutes a challenge for building predictive models for routine clinical practice. We describe a datamining framework that can unravel the higher order relationships among dosimetric dose-volume prognostic variables, interrogate various radiobiological processes, and generalize to unseen data before when applied prospectively. Several datamining approaches are discussed that include dose-volume metrics, equivalent uniform dose, mechanistic Poisson model, and model building methods using statistical regression and machine learning techniques. Institutional datasets of non-small cell lung cancer (NSCLC) patients are used to demonstrate these methods. The performance of the different methods was evaluated using bivariate Spearman rank correlations (rs). Over-fitting was controlled via resampling methods. Using a dataset of 56 patients with primary NCSLC tumors and 23 candidate variables, we estimated GTV volume and V75 to be the best model parameters for predicting TCP using statistical resampling and a logistic model. Using these variables, the support vector machine (SVM) kernel method provided superior performance for TCP prediction with an rs=0.68 on leave-one-out testing compared to logistic regression (rs=0.4), Poisson-based TCP (rs=0.33), and cell kill equivalent uniform dose model (rs=0.17). The prediction of treatment response can be improved by utilizing datamining approaches, which are able to unravel important non-linear complex interactions among model variables and have the capacity to predict on unseen data for prospective clinical applications.
Error statistics of hidden Markov model and hidden Boltzmann model results
Directory of Open Access Journals (Sweden)
Newberg Lee A
2009-07-01
Full Text Available Abstract Background Hidden Markov models and hidden Boltzmann models are employed in computational biology and a variety of other scientific fields for a variety of analyses of sequential data. Whether the associated algorithms are used to compute an actual probability or, more generally, an odds ratio or some other score, a frequent requirement is that the error statistics of a given score be known. What is the chance that random data would achieve that score or better? What is the chance that a real signal would achieve a given score threshold? Results Here we present a novel general approach to estimating these false positive and true positive rates that is significantly more efficient than are existing general approaches. We validate the technique via an implementation within the HMMER 3.0 package, which scans DNA or protein sequence databases for patterns of interest, using a profile-HMM. Conclusion The new approach is faster than general naïve sampling approaches, and more general than other current approaches. It provides an efficient mechanism by which to estimate error statistics for hidden Markov model and hidden Boltzmann model results.
Metamodelling Approach and Software Tools for Physical Modelling and Simulation
Directory of Open Access Journals (Sweden)
Vitaliy Mezhuyev
2015-02-01
Full Text Available In computer science, metamodelling approach becomes more and more popular for the purpose of software systems development. In this paper, we discuss applicability of the metamodelling approach for development of software tools for physical modelling and simulation.To define a metamodel for physical modelling the analysis of physical models will be done. The result of such the analyses will show the invariant physical structures, we propose to use as the basic abstractions of the physical metamodel. It is a system of geometrical objects, allowing to build a spatial structure of physical models and to set a distribution of physical properties. For such geometry of distributed physical properties, the different mathematical methods can be applied. To prove the proposed metamodelling approach, we consider the developed prototypes of software tools.
Crime Modeling using Spatial Regression Approach
Saleh Ahmar, Ansari; Adiatma; Kasim Aidid, M.
2018-01-01
Act of criminality in Indonesia increased both variety and quantity every year. As murder, rape, assault, vandalism, theft, fraud, fencing, and other cases that make people feel unsafe. Risk of society exposed to crime is the number of reported cases in the police institution. The higher of the number of reporter to the police institution then the number of crime in the region is increasing. In this research, modeling criminality in South Sulawesi, Indonesia with the dependent variable used is the society exposed to the risk of crime. Modelling done by area approach is the using Spatial Autoregressive (SAR) and Spatial Error Model (SEM) methods. The independent variable used is the population density, the number of poor population, GDP per capita, unemployment and the human development index (HDI). Based on the analysis using spatial regression can be shown that there are no dependencies spatial both lag or errors in South Sulawesi.
A Set Theoretical Approach to Maturity Models
DEFF Research Database (Denmark)
Lasrado, Lester; Vatrapu, Ravi; Andersen, Kim Normann
2016-01-01
of it application on a social media maturity data-set. Specifically, we employ Necessary Condition Analysis (NCA) to identify maturity stage boundaries as necessary conditions and Qualitative Comparative Analysis (QCA) to arrive at multiple configurations that can be equally effective in progressing to higher......Maturity Model research in IS has been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. To address these criticisms, this paper proposes a novel set-theoretical approach to maturity models...... characterized by equifinality, multiple conjunctural causation, and case diversity. We prescribe methodological guidelines consisting of a six-step procedure to systematically apply set theoretic methods to conceptualize, develop, and empirically derive maturity models and provide a demonstration...
An integrated modeling approach to age invariant face recognition
Alvi, Fahad Bashir; Pears, Russel
2015-03-01
This Research study proposes a novel method for face recognition based on Anthropometric features that make use of an integrated approach comprising of a global and personalized models. The system is aimed to at situations where lighting, illumination, and pose variations cause problems in face recognition. A Personalized model covers the individual aging patterns while a Global model captures general aging patterns in the database. We introduced a de-aging factor that de-ages each individual in the database test and training sets. We used the k nearest neighbor approach for building a personalized model and global model. Regression analysis was applied to build the models. During the test phase, we resort to voting on different features. We used FG-Net database for checking the results of our technique and achieved 65 percent Rank 1 identification rate.
A methodological approach for optimum preservation results: The packaging paradigm
Directory of Open Access Journals (Sweden)
Antonios Kanavouras
2017-04-01
Full Text Available The food preservation hypothesis as impacted by overall packaging applications is considered in this work. The objective was to devise a decision supportive method for the selection of “just-right” packaging materials, techniques and procedures. For that, food preservation was critically approached in order to identify the optimum outcome at experimental and packaging selection decision-making levels. A mathematically supported and proven knowledge classification, and the establishment of a straightforward coherence mode among the principles of the natural systemic phenomena, were used. The ultimate aim of this work was to justifiably surpass a simple description of packaging according to its measurable specifications, and instead, engage its inherent properties into a cyclic 8-steps-process for eventually understanding its potential to support any particular preservation hypothesis in question. The proposed methodology includes primarily, the consideration of the study hypothesis and, in parallel, the conclusive remarks and claims with respect to the experimental factors involved (properties, parameters, relations and conditions. Considering the experimentally controlled set-ups that a researcher has to expose the food system to and the role of packaging in obtaining its preservation potential, our method supports the experimenters in selecting the experimental conditions under which the preservation hypothesis can be disclaimed and furthermore, it could indicate the way to reduce experimentation research waste.
Sensitivity analysis approaches applied to systems biology models.
Zi, Z
2011-11-01
With the rising application of systems biology, sensitivity analysis methods have been widely applied to study the biological systems, including metabolic networks, signalling pathways and genetic circuits. Sensitivity analysis can provide valuable insights about how robust the biological responses are with respect to the changes of biological parameters and which model inputs are the key factors that affect the model outputs. In addition, sensitivity analysis is valuable for guiding experimental analysis, model reduction and parameter estimation. Local and global sensitivity analysis approaches are the two types of sensitivity analysis that are commonly applied in systems biology. Local sensitivity analysis is a classic method that studies the impact of small perturbations on the model outputs. On the other hand, global sensitivity analysis approaches have been applied to understand how the model outputs are affected by large variations of the model input parameters. In this review, the author introduces the basic concepts of sensitivity analysis approaches applied to systems biology models. Moreover, the author discusses the advantages and disadvantages of different sensitivity analysis methods, how to choose a proper sensitivity analysis approach, the available sensitivity analysis tools for systems biology models and the caveats in the interpretation of sensitivity analysis results.
A unified approach to several results involving integrals of multifunctions
Balder, E.J.
1991-01-01
A well-known equivalence of randomization result of Wald and Wolfowitz states that any Young measure can be regarded as a probability measure on the set of all measurable functions. Here we give a sucient condition for the Young measure to be equivalent to a probability measure on the set of all
A nationwide modelling approach to decommissioning - 16182
International Nuclear Information System (INIS)
Kelly, Bernard; Lowe, Andy; Mort, Paul
2009-01-01
In this paper we describe a proposed UK national approach to modelling decommissioning. For the first time, we shall have an insight into optimizing the safety and efficiency of a national decommissioning strategy. To do this we use the General Case Integrated Waste Algorithm (GIA), a universal model of decommissioning nuclear plant, power plant, waste arisings and the associated knowledge capture. The model scales from individual items of plant through cells, groups of cells, buildings, whole sites and then on up to a national scale. We describe the national vision for GIA which can be broken down into three levels: 1) the capture of the chronological order of activities that an experienced decommissioner would use to decommission any nuclear facility anywhere in the world - this is Level 1 of GIA; 2) the construction of an Operational Research (OR) model based on Level 1 to allow rapid what if scenarios to be tested quickly (Level 2); 3) the construction of a state of the art knowledge capture capability that allows future generations to learn from our current decommissioning experience (Level 3). We show the progress to date in developing GIA in levels 1 and 2. As part of level 1, GIA has assisted in the development of an IMechE professional decommissioning qualification. Furthermore, we describe GIA as the basis of a UK-Owned database of decommissioning norms for such things as costs, productivity, durations etc. From level 2, we report on a pilot study that has successfully tested the basic principles for the OR numerical simulation of the algorithm. We then highlight the advantages of applying the OR modelling approach nationally. In essence, a series of 'what if...' scenarios can be tested that will improve the safety and efficiency of decommissioning. (authors)
METHODOLOGICAL APPROACHES FOR MODELING THE RURAL SETTLEMENT DEVELOPMENT
Directory of Open Access Journals (Sweden)
Gorbenkova Elena Vladimirovna
2017-10-01
Full Text Available Subject: the paper describes the research results on validation of a rural settlement developmental model. The basic methods and approaches for solving the problem of assessment of the urban and rural settlement development efficiency are considered. Research objectives: determination of methodological approaches to modeling and creating a model for the development of rural settlements. Materials and methods: domestic and foreign experience in modeling the territorial development of urban and rural settlements and settlement structures was generalized. The motivation for using the Pentagon-model for solving similar problems was demonstrated. Based on a systematic analysis of existing development models of urban and rural settlements as well as the authors-developed method for assessing the level of agro-towns development, the systems/factors that are necessary for a rural settlement sustainable development are identified. Results: we created the rural development model which consists of five major systems that include critical factors essential for achieving a sustainable development of a settlement system: ecological system, economic system, administrative system, anthropogenic (physical system and social system (supra-structure. The methodological approaches for creating an evaluation model of rural settlements development were revealed; the basic motivating factors that provide interrelations of systems were determined; the critical factors for each subsystem were identified and substantiated. Such an approach was justified by the composition of tasks for territorial planning of the local and state administration levels. The feasibility of applying the basic Pentagon-model, which was successfully used for solving the analogous problems of sustainable development, was shown. Conclusions: the resulting model can be used for identifying and substantiating the critical factors for rural sustainable development and also become the basis of
Modeling in transport phenomena a conceptual approach
Tosun, Ismail
2007-01-01
Modeling in Transport Phenomena, Second Edition presents and clearly explains with example problems the basic concepts and their applications to fluid flow, heat transfer, mass transfer, chemical reaction engineering and thermodynamics. A balanced approach is presented between analysis and synthesis, students will understand how to use the solution in engineering analysis. Systematic derivations of the equations and the physical significance of each term are given in detail, for students to easily understand and follow up the material. There is a strong incentive in science and engineering to
Model approach brings multi-level success.
Howell, Mark
2012-08-01
n an article that first appeared in US magazine, Medical Construction & Design, Mark Howell, senior vice-president of Skanska USA Building, based in Seattle, describes the design and construction of a new nine-storey, 350,000 ft2 extension to the Good Samaritan Hospital in Puyallup, Washington state. He explains how the use of an Integrated Project Delivery (IPD) approach by the key players, and extensive use of building information modelling (BIM), combined to deliver a healthcare facility that he believes should meet the needs of patients, families, and the clinical care team, 'well into the future'.
Structural dialectical approach in psychology: problems and research results
Directory of Open Access Journals (Sweden)
Veraksa, Nikolay E.
2013-06-01
Full Text Available In this article dialectical thinking is regarded as one of the central cognitive processes. Because of this cognitive function we can analyze the development of processes and objects. It also determines the possibilities for the creative transformation of some content and for solving problems. The article presents a description and the results of experimental studies. This evidence proves that dialectical thinking is a specific line of cognitive development in children and adults. This line can degrade during school time if the educational program follows formal logical principles, or it can become significantly stronger if the pedagogy is based on dialectical methodology.
Pedagogic process modeling: Humanistic-integrative approach
Directory of Open Access Journals (Sweden)
Boritko Nikolaj M.
2007-01-01
Full Text Available The paper deals with some current problems of modeling the dynamics of the subject-features development of the individual. The term "process" is considered in the context of the humanistic-integrative approach, in which the principles of self education are regarded as criteria for efficient pedagogic activity. Four basic characteristics of the pedagogic process are pointed out: intentionality reflects logicality and regularity of the development of the process; discreteness (stageability in dicates qualitative stages through which the pedagogic phenomenon passes; nonlinearity explains the crisis character of pedagogic processes and reveals inner factors of self-development; situationality requires a selection of pedagogic conditions in accordance with the inner factors, which would enable steering the pedagogic process. Offered are two steps for singling out a particular stage and the algorithm for developing an integrative model for it. The suggested conclusions might be of use for further theoretic research, analyses of educational practices and for realistic predicting of pedagogical phenomena. .
Infectious disease modeling a hybrid system approach
Liu, Xinzhi
2017-01-01
This volume presents infectious diseases modeled mathematically, taking seasonality and changes in population behavior into account, using a switched and hybrid systems framework. The scope of coverage includes background on mathematical epidemiology, including classical formulations and results; a motivation for seasonal effects and changes in population behavior, an investigation into term-time forced epidemic models with switching parameters, and a detailed account of several different control strategies. The main goal is to study these models theoretically and to establish conditions under which eradication or persistence of the disease is guaranteed. In doing so, the long-term behavior of the models is determined through mathematical techniques from switched systems theory. Numerical simulations are also given to augment and illustrate the theoretical results and to help study the efficacy of the control schemes.
Intelligent Transportation and Evacuation Planning A Modeling-Based Approach
Naser, Arab
2012-01-01
Intelligent Transportation and Evacuation Planning: A Modeling-Based Approach provides a new paradigm for evacuation planning strategies and techniques. Recently, evacuation planning and modeling have increasingly attracted interest among researchers as well as government officials. This interest stems from the recent catastrophic hurricanes and weather-related events that occurred in the southeastern United States (Hurricane Katrina and Rita). The evacuation methods that were in place before and during the hurricanes did not work well and resulted in thousands of deaths. This book offers insights into the methods and techniques that allow for implementing mathematical-based, simulation-based, and integrated optimization and simulation-based engineering approaches for evacuation planning. This book also: Comprehensively discusses the application of mathematical models for evacuation and intelligent transportation modeling Covers advanced methodologies in evacuation modeling and planning Discusses principles a...
A modeling approach to hospital location for effective marketing.
Cokelez, S; Peacock, E
1993-01-01
This paper develops a mixed integer linear programming model for locating health care facilities. The parameters of the objective function of this model are based on factor rating analysis and grid method. Subjective and objective factors representative of the real life situations are incorporated into the model in a unique way permitting a trade-off analysis of certain factors pertinent to the location of hospitals. This results in a unified approach and a single model whose credibility is further enhanced by inclusion of geographical and demographical factors.
Joint Modeling of Multiple Crimes: A Bayesian Spatial Approach
Directory of Open Access Journals (Sweden)
Hongqiang Liu
2017-01-01
Full Text Available A multivariate Bayesian spatial modeling approach was used to jointly model the counts of two types of crime, i.e., burglary and non-motor vehicle theft, and explore the geographic pattern of crime risks and relevant risk factors. In contrast to the univariate model, which assumes independence across outcomes, the multivariate approach takes into account potential correlations between crimes. Six independent variables are included in the model as potential risk factors. In order to fully present this method, both the multivariate model and its univariate counterpart are examined. We fitted the two models to the data and assessed them using the deviance information criterion. A comparison of the results from the two models indicates that the multivariate model was superior to the univariate model. Our results show that population density and bar density are clearly associated with both burglary and non-motor vehicle theft risks and indicate a close relationship between these two types of crime. The posterior means and 2.5% percentile of type-specific crime risks estimated by the multivariate model were mapped to uncover the geographic patterns. The implications, limitations and future work of the study are discussed in the concluding section.
Earthquake response analysis of RC bridges using simplified modeling approaches
Lee, Do Hyung; Kim, Dookie; Park, Taehyo
2009-07-01
In this paper, simplified modeling approaches describing the hysteretic behavior of reinforced concrete bridge piers are proposed. For this purpose, flexure-axial and shear-axial interaction models are developed and implemented into a nonlinear finite element analysis program. Comparative verifications for reinforced concrete columns prove that the analytical predictions obtained with the new formulations show good correlation with experimental results under various levels of axial forces and section types. In addition, analytical correlation studies for the inelastic earthquake response of reinforced concrete bridge structures are also carried out using the simplified modeling approaches. Relatively good agreement is observed in the results between the current modeling approach and the elaborated fiber models. It is thus encouraging that the present developments and approaches are capable of identifying the contribution of deformation mechanisms correctly. Subsequently, the present developments can be used as a simple yet effective tool for the deformation capacity evaluation of reinforced concrete columns in general and reinforced concrete bridge piers in particular.
Modeling gene expression measurement error: a quasi-likelihood approach
Directory of Open Access Journals (Sweden)
Strimmer Korbinian
2003-03-01
Full Text Available Abstract Background Using suitable error models for gene expression measurements is essential in the statistical analysis of microarray data. However, the true probabilistic model underlying gene expression intensity readings is generally not known. Instead, in currently used approaches some simple parametric model is assumed (usually a transformed normal distribution or the empirical distribution is estimated. However, both these strategies may not be optimal for gene expression data, as the non-parametric approach ignores known structural information whereas the fully parametric models run the risk of misspecification. A further related problem is the choice of a suitable scale for the model (e.g. observed vs. log-scale. Results Here a simple semi-parametric model for gene expression measurement error is presented. In this approach inference is based an approximate likelihood function (the extended quasi-likelihood. Only partial knowledge about the unknown true distribution is required to construct this function. In case of gene expression this information is available in the form of the postulated (e.g. quadratic variance structure of the data. As the quasi-likelihood behaves (almost like a proper likelihood, it allows for the estimation of calibration and variance parameters, and it is also straightforward to obtain corresponding approximate confidence intervals. Unlike most other frameworks, it also allows analysis on any preferred scale, i.e. both on the original linear scale as well as on a transformed scale. It can also be employed in regression approaches to model systematic (e.g. array or dye effects. Conclusions The quasi-likelihood framework provides a simple and versatile approach to analyze gene expression data that does not make any strong distributional assumptions about the underlying error model. For several simulated as well as real data sets it provides a better fit to the data than competing models. In an example it also
Wave Resource Characterization Using an Unstructured Grid Modeling Approach
Directory of Open Access Journals (Sweden)
Wei-Cheng Wu
2018-03-01
Full Text Available This paper presents a modeling study conducted on the central Oregon coast for wave resource characterization, using the unstructured grid Simulating WAve Nearshore (SWAN model coupled with a nested grid WAVEWATCH III® (WWIII model. The flexibility of models with various spatial resolutions and the effects of open boundary conditions simulated by a nested grid WWIII model with different physics packages were evaluated. The model results demonstrate the advantage of the unstructured grid-modeling approach for flexible model resolution and good model skills in simulating the six wave resource parameters recommended by the International Electrotechnical Commission in comparison to the observed data in Year 2009 at National Data Buoy Center Buoy 46050. Notably, spectral analysis indicates that the ST4 physics package improves upon the ST2 physics package’s ability to predict wave power density for large waves, which is important for wave resource assessment, load calculation of devices, and risk management. In addition, bivariate distributions show that the simulated sea state of maximum occurrence with the ST4 physics package matched the observed data better than with the ST2 physics package. This study demonstrated that the unstructured grid wave modeling approach, driven by regional nested grid WWIII outputs along with the ST4 physics package, can efficiently provide accurate wave hindcasts to support wave resource characterization. Our study also suggests that wind effects need to be considered if the dimension of the model domain is greater than approximately 100 km, or O (102 km.
Approaches and models of intercultural education
Directory of Open Access Journals (Sweden)
Iván Manuel Sánchez Fontalvo
2013-10-01
Full Text Available Needed to be aware of the need to build an intercultural society, awareness must be assumed in all social spheres, where stands the role play education. A role of transcendental, since it must promote educational spaces to form people with virtues and powers that allow them to live together / as in multicultural contexts and social diversities (sometimes uneven in an increasingly globalized and interconnected world, and foster the development of feelings of civic belonging shared before the neighborhood, city, region and country, allowing them concern and critical judgement to marginalization, poverty, misery and inequitable distribution of wealth, causes of structural violence, but at the same time, wanting to work for the welfare and transformation of these scenarios. Since these budgets, it is important to know the approaches and models of intercultural education that have been developed so far, analysing their impact on the contexts educational where apply.
Assessing risk factors for dental caries: a statistical modeling approach.
Trottini, Mario; Bossù, Maurizio; Corridore, Denise; Ierardo, Gaetano; Luzzi, Valeria; Saccucci, Matteo; Polimeni, Antonella
2015-01-01
The problem of identifying potential determinants and predictors of dental caries is of key importance in caries research and it has received considerable attention in the scientific literature. From the methodological side, a broad range of statistical models is currently available to analyze dental caries indices (DMFT, dmfs, etc.). These models have been applied in several studies to investigate the impact of different risk factors on the cumulative severity of dental caries experience. However, in most of the cases (i) these studies focus on a very specific subset of risk factors; and (ii) in the statistical modeling only few candidate models are considered and model selection is at best only marginally addressed. As a result, our understanding of the robustness of the statistical inferences with respect to the choice of the model is very limited; the richness of the set of statistical models available for analysis in only marginally exploited; and inferences could be biased due the omission of potentially important confounding variables in the model's specification. In this paper we argue that these limitations can be overcome considering a general class of candidate models and carefully exploring the model space using standard model selection criteria and measures of global fit and predictive performance of the candidate models. Strengths and limitations of the proposed approach are illustrated with a real data set. In our illustration the model space contains more than 2.6 million models, which require inferences to be adjusted for 'optimism'.
A simplified GIS approach to modeling global leaf water isoscapes.
Directory of Open Access Journals (Sweden)
Jason B West
Full Text Available The stable hydrogen (delta(2H and oxygen (delta(18O isotope ratios of organic and inorganic materials record biological and physical processes through the effects of substrate isotopic composition and fractionations that occur as reactions proceed. At large scales, these processes can exhibit spatial predictability because of the effects of coherent climatic patterns over the Earth's surface. Attempts to model spatial variation in the stable isotope ratios of water have been made for decades. Leaf water has a particular importance for some applications, including plant organic materials that record spatial and temporal climate variability and that may be a source of food for migrating animals. It is also an important source of the variability in the isotopic composition of atmospheric gases. Although efforts to model global-scale leaf water isotope ratio spatial variation have been made (especially of delta(18O, significant uncertainty remains in models and their execution across spatial domains. We introduce here a Geographic Information System (GIS approach to the generation of global, spatially-explicit isotope landscapes (= isoscapes of "climate normal" leaf water isotope ratios. We evaluate the approach and the resulting products by comparison with simulation model outputs and point measurements, where obtainable, over the Earth's surface. The isoscapes were generated using biophysical models of isotope fractionation and spatially continuous precipitation isotope and climate layers as input model drivers. Leaf water delta(18O isoscapes produced here generally agreed with latitudinal averages from GCM/biophysical model products, as well as mean values from point measurements. These results show global-scale spatial coherence in leaf water isotope ratios, similar to that observed for precipitation and validate the GIS approach to modeling leaf water isotopes. These results demonstrate that relatively simple models of leaf water enrichment
Directory of Open Access Journals (Sweden)
Felisa Córdova G.
2017-06-01
Full Text Available In the 1990s, NASA implemented a programme named "Faster, Better, Cheaper," (FBC which involved essential changes to the way in which the organization used to be established. It was a huge organizational and transformational effort that required delivering dramatic advances in robustness, flexibility, and efficiency. Nevertheless in 1999, the failures of two consecutive Mars Climate Orbiter and Polar Lander missions brought to a stop of the FBC programme. We critically analyze and evaluate NASA's reorganization across of two models of organization theory such as the Diamond and Star, which show that FBC style needed a super-high-tech, a high level of complexity and novelty, and a time-critical pace. In addition, the majority of the missions' failures were also because of the short schedule, limited budget, and a deficient coordination of the processes management particularly in learning.
A consortium approach to glass furnace modeling.
Energy Technology Data Exchange (ETDEWEB)
Chang, S.-L.; Golchert, B.; Petrick, M.
1999-04-20
Using computational fluid dynamics to model a glass furnace is a difficult task for any one glass company, laboratory, or university to accomplish. The task of building a computational model of the furnace requires knowledge and experience in modeling two dissimilar regimes (the combustion space and the liquid glass bath), along with the skill necessary to couple these two regimes. Also, a detailed set of experimental data is needed in order to evaluate the output of the code to ensure that the code is providing proper results. Since all these diverse skills are not present in any one research institution, a consortium was formed between Argonne National Laboratory, Purdue University, Mississippi State University, and five glass companies in order to marshal these skills into one three-year program. The objective of this program is to develop a fully coupled, validated simulation of a glass melting furnace that may be used by industry to optimize the performance of existing furnaces.
A Genetic Algorithm Approach for Modeling a Grounding Electrode
Mishra, Arbind Kumar; Nagaoka, Naoto; Ametani, Akihiro
This paper has proposed a genetic algorithm based approach to determine a grounding electrode model circuit composed of resistances, inductances and capacitances. The proposed methodology determines the model circuit parameters based on a general ladder circuit directly from a measured result. Transient voltages of some electrodes were measured when applying a step like current. An EMTP simulation of a transient voltage on the grounding electrode has been carried out by adopting the proposed model circuits. The accuracy of the proposed method has been confirmed to be high in comparison with the measured transient voltage.
A Two Step Face Alignment Approach Using Statistical Models
Directory of Open Access Journals (Sweden)
Ying Cui
2012-10-01
Full Text Available Although face alignment using the Active Appearance Model (AAM is relatively stable, it is known to be sensitive to initial values and not robust under inconstant circumstances. In order to strengthen the ability of AAM performance for face alignment, a two step approach for face alignment combining AAM and Active Shape Model (ASM is proposed. In the first step, AAM is used to locate the inner landmarks of the face. In the second step, the extended ASM is used to locate the outer landmarks of the face under the constraint of the estimated inner landmarks by AAM. The two kinds of landmarks are then combined together to form the whole facial landmarks. The proposed approach is compared with the basic AAM and the progressive AAM methods. Experimental results show that the proposed approach gives a much more effective performance.
Systems Approaches to Modeling Chronic Mucosal Inflammation
Gao, Boning; Choudhary, Sanjeev; Wood, Thomas G.; Carmical, Joseph R.; Boldogh, Istvan; Mitra, Sankar; Minna, John D.; Brasier, Allan R.
2013-01-01
The respiratory mucosa is a major coordinator of the inflammatory response in chronic airway diseases, including asthma and chronic obstructive pulmonary disease (COPD). Signals produced by the chronic inflammatory process induce epithelial mesenchymal transition (EMT) that dramatically alters the epithelial cell phenotype. The effects of EMT on epigenetic reprogramming and the activation of transcriptional networks are known, its effects on the innate inflammatory response are underexplored. We used a multiplex gene expression profiling platform to investigate the perturbations of the innate pathways induced by TGFβ in a primary airway epithelial cell model of EMT. EMT had dramatic effects on the induction of the innate pathway and the coupling interval of the canonical and noncanonical NF-κB pathways. Simulation experiments demonstrate that rapid, coordinated cap-independent translation of TRAF-1 and NF-κB2 is required to reduce the noncanonical pathway coupling interval. Experiments using amantadine confirmed the prediction that TRAF-1 and NF-κB2/p100 production is mediated by an IRES-dependent mechanism. These data indicate that the epigenetic changes produced by EMT induce dynamic state changes of the innate signaling pathway. Further applications of systems approaches will provide understanding of this complex phenotype through deterministic modeling and multidimensional (genomic and proteomic) profiling. PMID:24228254
Comparative flood damage model assessment: towards a European approach
Jongman, B.; Kreibich, H.; Apel, H.; Barredo, J. I.; Bates, P. D.; Feyen, L.; Gericke, A.; Neal, J.; Aerts, J. C. J. H.; Ward, P. J.
2012-12-01
There is a wide variety of flood damage models in use internationally, differing substantially in their approaches and economic estimates. Since these models are being used more and more as a basis for investment and planning decisions on an increasingly large scale, there is a need to reduce the uncertainties involved and develop a harmonised European approach, in particular with respect to the EU Flood Risks Directive. In this paper we present a qualitative and quantitative assessment of seven flood damage models, using two case studies of past flood events in Germany and the United Kingdom. The qualitative analysis shows that modelling approaches vary strongly, and that current methodologies for estimating infrastructural damage are not as well developed as methodologies for the estimation of damage to buildings. The quantitative results show that the model outcomes are very sensitive to uncertainty in both vulnerability (i.e. depth-damage functions) and exposure (i.e. asset values), whereby the first has a larger effect than the latter. We conclude that care needs to be taken when using aggregated land use data for flood risk assessment, and that it is essential to adjust asset values to the regional economic situation and property characteristics. We call for the development of a flexible but consistent European framework that applies best practice from existing models while providing room for including necessary regional adjustments.
Basta, Marten N; Fischer, John P; Lotano, Vincent E; Kovach, Stephen J
2014-12-01
Chest wall reconstruction remains challenging because of the variable nature of the defect. Muscle-sparing approaches have been described but are not widely applied today. The authors reviewed an institutional experience with chest wall reconstruction and describe the thoracoplastic approach, which aims to optimize flap selection. A retrospective review was conducted identifying all patients undergoing chest wall reconstruction performed by the senior author. Demographic information and operative characteristics were detailed and factors were analyzed for association with postoperative outcomes. Outcomes were also compared for conventional versus thoracoplastic groups. Forty-five patients underwent chest wall reconstruction at an average age of 54.2 ± 16.3 years. Sarcomas were most common (51 percent), followed by breast (16 percent) and lung (11 percent). The average number of ribs resected was 3.2 ± 1.4, with an average defect size of 212 ± 185 cm2. The most commonly used flaps included the latissimus dorsi and pectoralis major (72 percent). Mesh was incorporated in 58 percent of repairs and operative time was 6.2 ± 2.5 hours. The incidence of surgical complications was 23 percent, most commonly wound infection and nonhealing wound (20 percent). The thoracoplastic approach, used in 14 patients, demonstrated no differences in outcomes with follow-up of 14 months. Operative time was nearly identical, and the thoracoplastic group required significantly less blood products when transfused. Latissimus dorsi and pectoralis major flaps were used more frequently in the thoracoplastic group, although this did not reach significance (78.6 percent versus 69.2 percent). The thoracoplastic approach appears to be safe and effective when compared with conventional methods. Although definitive conclusions cannot be drawn, the authors' early experience is promising. The authors believe applying these principles improves aesthetic and functional outcomes and preserves the
The Generalised Ecosystem Modelling Approach in Radiological Assessment
Energy Technology Data Exchange (ETDEWEB)
Klos, Richard
2008-03-15
An independent modelling capability is required by SSI in order to evaluate dose assessments carried out in Sweden by, amongst others, SKB. The main focus is the evaluation of the long-term radiological safety of radioactive waste repositories for both spent fuel and low-level radioactive waste. To meet the requirement for an independent modelling tool for use in biosphere dose assessments, SSI through its modelling team CLIMB commissioned the development of a new model in 2004, a project to produce an integrated model of radionuclides in the landscape. The generalised ecosystem modelling approach (GEMA) is the result. GEMA is a modular system of compartments representing the surface environment. It can be configured, through water and solid material fluxes, to represent local details in the range of ecosystem types found in the past, present and future Swedish landscapes. The approach is generic but fine tuning can be carried out using local details of the surface drainage system. The modular nature of the modelling approach means that GEMA modules can be linked to represent large scale surface drainage features over an extended domain in the landscape. System change can also be managed in GEMA, allowing a flexible and comprehensive model of the evolving landscape to be constructed. Environmental concentrations of radionuclides can be calculated and the GEMA dose pathway model provides a means of evaluating the radiological impact of radionuclide release to the surface environment. This document sets out the philosophy and details of GEMA and illustrates the functioning of the model with a range of examples featuring the recent CLIMB review of SKB's SR-Can assessment
Accurate phenotyping: Reconciling approaches through Bayesian model averaging.
Directory of Open Access Journals (Sweden)
Carla Chia-Ming Chen
Full Text Available Genetic research into complex diseases is frequently hindered by a lack of clear biomarkers for phenotype ascertainment. Phenotypes for such diseases are often identified on the basis of clinically defined criteria; however such criteria may not be suitable for understanding the genetic composition of the diseases. Various statistical approaches have been proposed for phenotype definition; however our previous studies have shown that differences in phenotypes estimated using different approaches have substantial impact on subsequent analyses. Instead of obtaining results based upon a single model, we propose a new method, using Bayesian model averaging to overcome problems associated with phenotype definition. Although Bayesian model averaging has been used in other fields of research, this is the first study that uses Bayesian model averaging to reconcile phenotypes obtained using multiple models. We illustrate the new method by applying it to simulated genetic and phenotypic data for Kofendred personality disorder-an imaginary disease with several sub-types. Two separate statistical methods were used to identify clusters of individuals with distinct phenotypes: latent class analysis and grade of membership. Bayesian model averaging was then used to combine the two clusterings for the purpose of subsequent linkage analyses. We found that causative genetic loci for the disease produced higher LOD scores using model averaging than under either individual model separately. We attribute this improvement to consolidation of the cores of phenotype clusters identified using each individual method.
Integration models: multicultural and liberal approaches confronted
Janicki, Wojciech
2012-01-01
European societies have been shaped by their Christian past, upsurge of international migration, democratic rule and liberal tradition rooted in religious tolerance. Boosting globalization processes impose new challenges on European societies, striving to protect their diversity. This struggle is especially clearly visible in case of minorities trying to resist melting into mainstream culture. European countries' legal systems and cultural policies respond to these efforts in many ways. Respecting identity politics-driven group rights seems to be the most common approach, resulting in creation of a multicultural society. However, the outcome of respecting group rights may be remarkably contradictory to both individual rights growing out from liberal tradition, and to reinforced concept of integration of immigrants into host societies. The hereby paper discusses identity politics upturn in the context of both individual rights and integration of European societies.
Risk communication: a mental models approach
National Research Council Canada - National Science Library
Morgan, M. Granger (Millett Granger)
2002-01-01
... information about risks. The procedure uses approaches from risk and decision analysis to identify the most relevant information; it also uses approaches from psychology and communication theory to ensure that its message is understood. This book is written in nontechnical terms, designed to make the approach feasible for anyone willing to try it. It is illustrat...
Medical Inpatient Journey Modeling and Clustering: A Bayesian Hidden Markov Model Based Approach.
Huang, Zhengxing; Dong, Wei; Wang, Fei; Duan, Huilong
2015-01-01
Modeling and clustering medical inpatient journeys is useful to healthcare organizations for a number of reasons including inpatient journey reorganization in a more convenient way for understanding and browsing, etc. In this study, we present a probabilistic model-based approach to model and cluster medical inpatient journeys. Specifically, we exploit a Bayesian Hidden Markov Model based approach to transform medical inpatient journeys into a probabilistic space, which can be seen as a richer representation of inpatient journeys to be clustered. Then, using hierarchical clustering on the matrix of similarities, inpatient journeys can be clustered into different categories w.r.t their clinical and temporal characteristics. We evaluated the proposed approach on a real clinical data set pertaining to the unstable angina treatment process. The experimental results reveal that our method can identify and model latent treatment topics underlying in personalized inpatient journeys, and yield impressive clustering quality.
Impact Flash Physics: Modeling and Comparisons With Experimental Results
Rainey, E.; Stickle, A. M.; Ernst, C. M.; Schultz, P. H.; Mehta, N. L.; Brown, R. C.; Swaminathan, P. K.; Michaelis, C. H.; Erlandson, R. E.
2015-12-01
Hypervelocity impacts frequently generate an observable "flash" of light with two components: a short-duration spike due to emissions from vaporized material, and a long-duration peak due to thermal emissions from expanding hot debris. The intensity and duration of these peaks depend on the impact velocity, angle, and the target and projectile mass and composition. Thus remote sensing measurements of planetary impact flashes have the potential to constrain the properties of impacting meteors and improve our understanding of impact flux and cratering processes. Interpreting impact flash measurements requires a thorough understanding of how flash characteristics correlate with impact conditions. Because planetary-scale impacts cannot be replicated in the laboratory, numerical simulations are needed to provide this insight for the solar system. Computational hydrocodes can produce detailed simulations of the impact process, but they lack the radiation physics required to model the optical flash. The Johns Hopkins University Applied Physics Laboratory (APL) developed a model to calculate the optical signature from the hot debris cloud produced by an impact. While the phenomenology of the optical signature is understood, the details required to accurately model it are complicated by uncertainties in material and optical properties and the simplifications required to numerically model radiation from large-scale impacts. Comparisons with laboratory impact experiments allow us to validate our approach and to draw insight regarding processes that occur at all scales in impact events, such as melt generation. We used Sandia National Lab's CTH shock physics hydrocode along with the optical signature model developed at APL to compare with a series of laboratory experiments conducted at the NASA Ames Vertical Gun Range. The experiments used Pyrex projectiles to impact pumice powder targets with velocities ranging from 1 to 6 km/s at angles of 30 and 90 degrees with respect to
New analytic results for speciation times in neutral models.
Gernhard, Tanja
2008-05-01
In this paper, we investigate the standard Yule model, and a recently studied model of speciation and extinction, the "critical branching process." We develop an analytic way-as opposed to the common simulation approach-for calculating the speciation times in a reconstructed phylogenetic tree. Simple expressions for the density and the moments of the speciation times are obtained. Methods for dating a speciation event become valuable, if for the reconstructed phylogenetic trees, no time scale is available. A missing time scale could be due to supertree methods, morphological data, or molecular data which violates the molecular clock. Our analytic approach is, in particular, useful for the model with extinction, since simulations of birth-death processes which are conditioned on obtaining n extant species today are quite delicate. Further, simulations are very time consuming for big n under both models.
A Conditional Approach to Panel Data Models with Common Shocks
Directory of Open Access Journals (Sweden)
Giovanni Forchini
2016-01-01
Full Text Available This paper studies the effects of common shocks on the OLS estimators of the slopes’ parameters in linear panel data models. The shocks are assumed to affect both the errors and some of the explanatory variables. In contrast to existing approaches, which rely on using results on martingale difference sequences, our method relies on conditional strong laws of large numbers and conditional central limit theorems for conditionally-heterogeneous random variables.
Polynomial Chaos Expansion Approach to Interest Rate Models
Directory of Open Access Journals (Sweden)
Luca Di Persio
2015-01-01
Full Text Available The Polynomial Chaos Expansion (PCE technique allows us to recover a finite second-order random variable exploiting suitable linear combinations of orthogonal polynomials which are functions of a given stochastic quantity ξ, hence acting as a kind of random basis. The PCE methodology has been developed as a mathematically rigorous Uncertainty Quantification (UQ method which aims at providing reliable numerical estimates for some uncertain physical quantities defining the dynamic of certain engineering models and their related simulations. In the present paper, we use the PCE approach in order to analyze some equity and interest rate models. In particular, we take into consideration those models which are based on, for example, the Geometric Brownian Motion, the Vasicek model, and the CIR model. We present theoretical as well as related concrete numerical approximation results considering, without loss of generality, the one-dimensional case. We also provide both an efficiency study and an accuracy study of our approach by comparing its outputs with the ones obtained adopting the Monte Carlo approach, both in its standard and its enhanced version.
Energy and Development. A Modelling Approach
International Nuclear Information System (INIS)
Van Ruijven, B.J.
2008-01-01
Rapid economic growth of developing countries like India and China implies that these countries become important actors in the global energy system. Examples of this impact are the present day oil shortages and rapidly increasing emissions of greenhouse gases. Global energy models are used to explore possible future developments of the global energy system and identify policies to prevent potential problems. Such estimations of future energy use in developing countries are very uncertain. Crucial factors in the future energy use of these regions are electrification, urbanisation and income distribution, issues that are generally not included in present day global energy models. Model simulations in this thesis show that current insight in developments in low-income regions lead to a wide range of expected energy use in 2030 of the residential and transport sectors. This is mainly caused by many different model calibration options that result from the limited data availability for model development and calibration. We developed a method to identify the impact of model calibration uncertainty on future projections. We developed a new model for residential energy use in India, in collaboration with the Indian Institute of Science. Experiments with this model show that the impact of electrification and income distribution is less univocal than often assumed. The use of fuelwood, with related health risks, can decrease rapidly if the income of poor groups increases. However, there is a trade off in terms of CO2 emissions because these groups gain access to electricity and the ownership of appliances increases. Another issue is the potential role of new technologies in developing countries: will they use the opportunities of leapfrogging? We explored the potential role of hydrogen, an energy carrier that might play a central role in a sustainable energy system. We found that hydrogen only plays a role before 2050 under very optimistic assumptions. Regional energy
Energy and Development. A Modelling Approach
Energy Technology Data Exchange (ETDEWEB)
Van Ruijven, B.J.
2008-12-17
Rapid economic growth of developing countries like India and China implies that these countries become important actors in the global energy system. Examples of this impact are the present day oil shortages and rapidly increasing emissions of greenhouse gases. Global energy models are used to explore possible future developments of the global energy system and identify policies to prevent potential problems. Such estimations of future energy use in developing countries are very uncertain. Crucial factors in the future energy use of these regions are electrification, urbanisation and income distribution, issues that are generally not included in present day global energy models. Model simulations in this thesis show that current insight in developments in low-income regions lead to a wide range of expected energy use in 2030 of the residential and transport sectors. This is mainly caused by many different model calibration options that result from the limited data availability for model development and calibration. We developed a method to identify the impact of model calibration uncertainty on future projections. We developed a new model for residential energy use in India, in collaboration with the Indian Institute of Science. Experiments with this model show that the impact of electrification and income distribution is less univocal than often assumed. The use of fuelwood, with related health risks, can decrease rapidly if the income of poor groups increases. However, there is a trade off in terms of CO2 emissions because these groups gain access to electricity and the ownership of appliances increases. Another issue is the potential role of new technologies in developing countries: will they use the opportunities of leapfrogging? We explored the potential role of hydrogen, an energy carrier that might play a central role in a sustainable energy system. We found that hydrogen only plays a role before 2050 under very optimistic assumptions. Regional energy
ISM Approach to Model Offshore Outsourcing Risks
Directory of Open Access Journals (Sweden)
Sunand Kumar
2014-07-01
Full Text Available In an effort to achieve a competitive advantage via cost reductions and improved market responsiveness, organizations are increasingly employing offshore outsourcing as a major component of their supply chain strategies. But as evident from literature number of risks such as Political risk, Risk due to cultural differences, Compliance and regulatory risk, Opportunistic risk and Organization structural risk, which adversely affect the performance of offshore outsourcing in a supply chain network. This also leads to dissatisfaction among different stake holders. The main objective of this paper is to identify and understand the mutual interaction among various risks which affect the performance of offshore outsourcing. To this effect, authors have identified various risks through extant review of literature. From this information, an integrated model using interpretive structural modelling (ISM for risks affecting offshore outsourcing is developed and the structural relationships between these risks are modeled. Further, MICMAC analysis is done to analyze the driving power and dependency of risks which shall be helpful to managers to identify and classify important criterions and to reveal the direct and indirect effects of each criterion on offshore outsourcing. Results show that political risk and risk due to cultural differences are act as strong drivers.
Metabolic network modeling approaches for investigating the "hungry cancer".
Sharma, Ashwini Kumar; König, Rainer
2013-08-01
Metabolism is the functional phenotype of a cell, at a given condition, resulting from an intricate interplay of various regulatory processes. The study of these dynamic metabolic processes and their capabilities help to identify the fundamental properties of living systems. Metabolic deregulation is an emerging hallmark of cancer cells. This deregulation results in rewiring of the metabolic circuitry conferring an exploitative metabolic advantage for the tumor cells which leads to a distinct benefit in survival and lays the basis for unbound progression. Metabolism can be considered as a thermodynamic open-system in which source substrates of high value are being processed through a well established interconnected biochemical conversion system, strictly obeying physiochemical principles, generating useful intermediates and finally resulting in the release of byproducts. Based on this basic principle of an input-output balance, various models have been developed to interrogate metabolism elucidating its underlying functional properties. However, only a few modeling approaches have proved computationally feasible in elucidating the metabolic nature of cancer at a systems level. Besides this, statistical approaches have been set up to identify biochemical pathways being more relevant for specific types of tumor cells. In this review, we are briefly introducing the basic statistical approaches followed by the major modeling concepts. We have put an emphasis on the methods and their applications that have been used to a greater extent in understanding the metabolic remodeling of cancer. Copyright © 2013 Elsevier Ltd. All rights reserved.
Genetic Algorithm Approaches to Prebiobiotic Chemistry Modeling
Lohn, Jason; Colombano, Silvano
1997-01-01
We model an artificial chemistry comprised of interacting polymers by specifying two initial conditions: a distribution of polymers and a fixed set of reversible catalytic reactions. A genetic algorithm is used to find a set of reactions that exhibit a desired dynamical behavior. Such a technique is useful because it allows an investigator to determine whether a specific pattern of dynamics can be produced, and if it can, the reaction network found can be then analyzed. We present our results in the context of studying simplified chemical dynamics in theorized protocells - hypothesized precursors of the first living organisms. Our results show that given a small sample of plausible protocell reaction dynamics, catalytic reaction sets can be found. We present cases where this is not possible and also analyze the evolved reaction sets.
Vandegriend, A. A.; Owe, M.; Vugts, H. F.; Ramothwa, G. K.
1992-01-01
The Botswana water and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. Results of the first part of the program (Botswana 1) which ran from 1 Jan. 1988 - 31 Dec. 1990 are summarized. Botswana 1 consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive microwave research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel microwave radiometer microwave signatures. The integrated approach of both components in general are described and activities performed during the surface energy modeling component including the extensive field campaign are summarized. The results of the passive microwave component are summarized. The key of the field campaign was a multilevel approach, whereby measurements by various similar sensors were made at several altitudes and resolution. Data collection was performed at two adjacent sites of contrasting surface character. The following measurements were made: micrometeorological measurements, surface temperatures, soil temperatures, soil moisture, vegetation (leaf area index and biomass), satellite data, aircraft data, atmospheric soundings, stomatal resistance, and surface emissivity.
Prediction of the flooding process at the Ronneburg site - results of an integrated approach
International Nuclear Information System (INIS)
Paul, M.; Saenger, H.-J.; Snagowski, S.; Maerten, H.; Eckart, M.
1998-01-01
The flooding process of the Ronneburg uranium mine (WISMUT) was initiated at the turn of the year 1997 to 1998. In order to prepare the flooding process and to derive and optimize technological measures an integrated modelling approach was chosen which includes several coupled modules. The most important issues to be answered are: (1) prediction of the flooding time (2) prediction of the groundwater level at the post-flooding stage, assessment of amount, location and quality of flooding waters entering the receiving streams at the final stage (3) water quality prediction within the mine during the flooding process (4) definition of technological measures and assessment of their efficiency A box model which includes the three-dimensional distribution of the cavity volume in the mine represents the model core. The model considers the various types of dewatered cavity volumes for each mine level / mining field and the degree of vertical and horizontal connection between the mining fields. Different types of open mine space as well as the dewatered geological pore and joint volume are considered taking into account the contour of the depression cone prior to flooding and the characteristics of the different rock types. Based on the mine water balance and the flooding technology the model predicts the rise of the water table over time during the flooding process for each mine field separately. In order to predict the mine water quality and the efficiency of in-situ water treatment the box model was linked to a geochemical model (PHREEQC). A three-dimensional flow model is used to evaluate the post-flooding situation at the Ronneburg site. This model is coupled to the box model. The modelling results of various flooding scenarios show that a prediction of the post-flooding geohydraulic situation is possible despite of uncertainties concerning the input parameters which still exist. The post-flooding water table in the central part of the Ronneburg mine will be 270 m
A global sensitivity analysis approach for morphogenesis models
Boas, Sonja E. M.
2015-11-21
Background Morphogenesis is a developmental process in which cells organize into shapes and patterns. Complex, non-linear and multi-factorial models with images as output are commonly used to study morphogenesis. It is difficult to understand the relation between the uncertainty in the input and the output of such ‘black-box’ models, giving rise to the need for sensitivity analysis tools. In this paper, we introduce a workflow for a global sensitivity analysis approach to study the impact of single parameters and the interactions between them on the output of morphogenesis models. Results To demonstrate the workflow, we used a published, well-studied model of vascular morphogenesis. The parameters of this cellular Potts model (CPM) represent cell properties and behaviors that drive the mechanisms of angiogenic sprouting. The global sensitivity analysis correctly identified the dominant parameters in the model, consistent with previous studies. Additionally, the analysis provided information on the relative impact of single parameters and of interactions between them. This is very relevant because interactions of parameters impede the experimental verification of the predicted effect of single parameters. The parameter interactions, although of low impact, provided also new insights in the mechanisms of in silico sprouting. Finally, the analysis indicated that the model could be reduced by one parameter. Conclusions We propose global sensitivity analysis as an alternative approach to study the mechanisms of morphogenesis. Comparison of the ranking of the impact of the model parameters to knowledge derived from experimental data and from manipulation experiments can help to falsify models and to find the operand mechanisms in morphogenesis. The workflow is applicable to all ‘black-box’ models, including high-throughput in vitro models in which output measures are affected by a set of experimental perturbations.
Banking Crisis Early Warning Model based on a Bayesian Model Averaging Approach
Directory of Open Access Journals (Sweden)
Taha Zaghdoudi
2016-08-01
Full Text Available The succession of banking crises in which most have resulted in huge economic and financial losses, prompted several authors to study their determinants. These authors constructed early warning models to prevent their occurring. It is in this same vein as our study takes its inspiration. In particular, we have developed a warning model of banking crises based on a Bayesian approach. The results of this approach have allowed us to identify the involvement of the decline in bank profitability, deterioration of the competitiveness of the traditional intermediation, banking concentration and higher real interest rates in triggering bank crisis.
Social Network Analyses and Nutritional Behavior: An Integrated Modeling Approach
Directory of Open Access Journals (Sweden)
Alistair McNair Senior
2016-01-01
Full Text Available Animals have evolved complex foraging strategies to obtain a nutritionally balanced diet and associated fitness benefits. Recent advances in nutrition research, combining state-space models of nutritional geometry with agent-based models of systems biology, show how nutrient targeted foraging behavior can also influence animal social interactions, ultimately affecting collective dynamics and group structures. Here we demonstrate how social network analyses can be integrated into such a modeling framework and provide a tangible and practical analytical tool to compare experimental results with theory. We illustrate our approach by examining the case of nutritionally mediated dominance hierarchies. First we show how nutritionally explicit agent-based models that simulate the emergence of dominance hierarchies can be used to generate social networks. Importantly the structural properties of our simulated networks bear similarities to dominance networks of real animals (where conflicts are not always directly related to nutrition. Finally, we demonstrate how metrics from social network analyses can be used to predict the fitness of agents in these simulated competitive environments. Our results highlight the potential importance of nutritional mechanisms in shaping dominance interactions in a wide range of social and ecological contexts. Nutrition likely influences social interaction in many species, and yet a theoretical framework for exploring these effects is currently lacking. Combining social network analyses with computational models from nutritional ecology may bridge this divide, representing a pragmatic approach for generating theoretical predictions for nutritional experiments.
Elyasberg, P. Y.
1979-01-01
The shortcomings of the classical approach are set forth, and the newer methods resulting from these shortcomings are explained. The problem was approached with the assumption that the probabilities of error were known, as well as without knowledge of the distribution of the probabilities of error. The advantages of the newer approach are discussed.
Modeling energy fluxes in heterogeneous landscapes employing a mosaic approach
Klein, Christian; Thieme, Christoph; Priesack, Eckart
2015-04-01
Recent studies show that uncertainties in regional and global climate and weather simulations are partly due to inadequate descriptions of the energy flux exchanges between the land surface and the atmosphere. One major shortcoming is the limitation of the grid-cell resolution, which is recommended to be about at least 3x3 km² in most models due to limitations in the model physics. To represent each individual grid cell most models select one dominant soil type and one dominant land use type. This resolution, however, is often too coarse in regions where the spatial diversity of soil and land use types are high, e.g. in Central Europe. An elegant method to avoid the shortcoming of grid cell resolution is the so called mosaic approach. This approach is part of the recently developed ecosystem model framework Expert-N 5.0. The aim of this study was to analyze the impact of the characteristics of two managed fields, planted with winter wheat and potato, on the near surface soil moistures and on the near surface energy flux exchanges of the soil-plant-atmosphere interface. The simulated energy fluxes were compared with eddy flux tower measurements between the respective fields at the research farm Scheyern, North-West of Munich, Germany. To perform these simulations, we coupled the ecosystem model Expert-N 5.0 to an analytical footprint model. The coupled model system has the ability to calculate the mixing ratio of the surface energy fluxes at a given point within one grid cell (in this case at the flux tower between the two fields). This approach accounts for the differences of the two soil types, of land use managements, and of canopy properties due to footprint size dynamics. Our preliminary simulation results show that a mosaic approach can improve modeling and analyzing energy fluxes when the land surface is heterogeneous. In this case our applied method is a promising approach to extend weather and climate models on the regional and on the global scale.
A Discrete Monetary Economic Growth Model with the MIU Approach
Directory of Open Access Journals (Sweden)
Wei-Bin Zhang
2008-01-01
Full Text Available This paper proposes an alternative approach to economic growth with money. The production side is the same as the Solow model, the Ramsey model, and the Tobin model. But we deal with behavior of consumers differently from the traditional approaches. The model is influenced by the money-in-the-utility (MIU approach in monetary economics. It provides a mechanism of endogenous saving which the Solow model lacks and avoids the assumption of adding up utility over a period of time upon which the Ramsey approach is based.
Consensus approach for modeling HTS assays using in silico descriptors
Directory of Open Access Journals (Sweden)
Ahmed eAbdelaziz Sayed
2016-02-01
Full Text Available The need for filling information gaps while reducing toxicity testing in animals is becoming more predominant in risk assessment. Recent legislations are accepting in silico approaches for predicting toxicological outcomes. This article describes the results of Quantitative Structure Activity Relationship (QSAR modeling efforts within Tox21 Data Challenge 2014, which calculated the best balanced accuracy across all molecular pathway endpoints as well as the highest scores for ATAD5 and mitochondrial membrane potential disruption. Automated QSPR workflow systems, OCHEM (http://ochem.eu, the analytics platform, KNIME and the statistics software, CRAN R, were used to conduct the analysis and develop consensus models using ten different descriptor sets. A detailed analysis of QSAR models for all 12 molecular pathways and the effect of underlying models’ accuracy on the quality of the consensus model are provided. The resulting consensus models yielded a balanced accuracy as high as 88.1%±0.6 for mitochondrial membrane disruptors. Such high balanced accuracy and use of the applicability domain show a promising potential for in silico modeling to complement design HTS screening experiments. The summary statistics of all models are publicly available online at https://github.com/amaziz/Tox21-Challenge-Publication while the developed consensus models can be accessed at http://ochem.eu/article/98009.
Agribusiness model approach to territorial food development
Directory of Open Access Journals (Sweden)
Murcia Hector Horacio
2011-04-01
Full Text Available
Several research efforts have coordinated the academic program of Agricultural Business Management from the University De La Salle (Bogota D.C., to the design and implementation of a sustainable agribusiness model applied to food development, with territorial projection. Rural development is considered as a process that aims to improve the current capacity and potential of the inhabitant of the sector, which refers not only to production levels and productivity of agricultural items. It takes into account the guidelines of the Organization of the United Nations “Millennium Development Goals” and considered the concept of sustainable food and agriculture development, including food security and nutrition in an integrated interdisciplinary context, with holistic and systemic dimension. Analysis is specified by a model with an emphasis on sustainable agribusiness production chains related to agricultural food items in a specific region. This model was correlated with farm (technical objectives, family (social purposes and community (collective orientations projects. Within this dimension are considered food development concepts and methodologies of Participatory Action Research (PAR. Finally, it addresses the need to link the results to low-income communities, within the concepts of the “new rurality”.
Some results regarding the comparison of the Earth's atmospheric models
Directory of Open Access Journals (Sweden)
Šegan S.
2005-01-01
Full Text Available In this paper we examine air densities derived from our realization of aeronomic atmosphere models based on accelerometer measurements from satellites in a low Earth's orbit (LEO. Using the adapted algorithms we derive comparison parameters. The first results concerning the adjustment of the aeronomic models to the total-density model are given.
A modal approach to modeling spatially distributed vibration energy dissipation.
Energy Technology Data Exchange (ETDEWEB)
Segalman, Daniel Joseph
2010-08-01
The nonlinear behavior of mechanical joints is a confounding element in modeling the dynamic response of structures. Though there has been some progress in recent years in modeling individual joints, modeling the full structure with myriad frictional interfaces has remained an obstinate challenge. A strategy is suggested for structural dynamics modeling that can account for the combined effect of interface friction distributed spatially about the structure. This approach accommodates the following observations: (1) At small to modest amplitudes, the nonlinearity of jointed structures is manifest primarily in the energy dissipation - visible as vibration damping; (2) Correspondingly, measured vibration modes do not change significantly with amplitude; and (3) Significant coupling among the modes does not appear to result at modest amplitudes. The mathematical approach presented here postulates the preservation of linear modes and invests all the nonlinearity in the evolution of the modal coordinates. The constitutive form selected is one that works well in modeling spatially discrete joints. When compared against a mathematical truth model, the distributed dissipation approximation performs well.
Innovation Networks New Approaches in Modelling and Analyzing
Pyka, Andreas
2009-01-01
The science of graphs and networks has become by now a well-established tool for modelling and analyzing a variety of systems with a large number of interacting components. Starting from the physical sciences, applications have spread rapidly to the natural and social sciences, as well as to economics, and are now further extended, in this volume, to the concept of innovations, viewed broadly. In an abstract, systems-theoretical approach, innovation can be understood as a critical event which destabilizes the current state of the system, and results in a new process of self-organization leading to a new stable state. The contributions to this anthology address different aspects of the relationship between innovation and networks. The various chapters incorporate approaches in evolutionary economics, agent-based modeling, social network analysis and econophysics and explore the epistemic tension between insights into economics and society-related processes, and the insights into new forms of complex dynamics.
Functional RG approach to the Potts model
Ben Alì Zinati, Riccardo; Codello, Alessandro
2018-01-01
The critical behavior of the (n+1) -states Potts model in d-dimensions is studied with functional renormalization group techniques. We devise a general method to derive β-functions for continuous values of d and n and we write the flow equation for the effective potential (LPA’) when instead n is fixed. We calculate several critical exponents, which are found to be in good agreement with Monte Carlo simulations and ɛ-expansion results available in the literature. In particular, we focus on Percolation (n\\to0) and Spanning Forest (n\\to-1) which are the only non-trivial universality classes in d = 4,5 and where our methods converge faster.
Wind Turbine Control: Robust Model Based Approach
DEFF Research Database (Denmark)
Mirzaei, Mahmood
. This is because, on the one hand, control methods can decrease the cost of energy by keeping the turbine close to its maximum efficiency. On the other hand, they can reduce structural fatigue and therefore increase the lifetime of the wind turbine. The power produced by a wind turbine is proportional...... to the square of its rotor radius, therefore it seems reasonable to increase the size of the wind turbine in order to capture more power. However as the size increases, the mass of the blades increases by cube of the rotor size. This means in order to keep structural feasibility and mass of the whole structure...... reasonable, the ratio of mass to size should be reduced. This trend results in more flexible structures. Control of the flexible structure of a wind turbine in a wind field with stochastic nature is very challenging. In this thesis we are examining a number of robust model based methods for wind turbine...
Systematic approach to verification and validation: High explosive burn models
Energy Technology Data Exchange (ETDEWEB)
Menikoff, Ralph [Los Alamos National Laboratory; Scovel, Christina A. [Los Alamos National Laboratory
2012-04-16
Most material models used in numerical simulations are based on heuristics and empirically calibrated to experimental data. For a specific model, key questions are determining its domain of applicability and assessing its relative merits compared to other models. Answering these questions should be a part of model verification and validation (V and V). Here, we focus on V and V of high explosive models. Typically, model developers implemented their model in their own hydro code and use different sets of experiments to calibrate model parameters. Rarely can one find in the literature simulation results for different models of the same experiment. Consequently, it is difficult to assess objectively the relative merits of different models. This situation results in part from the fact that experimental data is scattered through the literature (articles in journals and conference proceedings) and that the printed literature does not allow the reader to obtain data from a figure in electronic form needed to make detailed comparisons among experiments and simulations. In addition, it is very time consuming to set up and run simulations to compare different models over sufficiently many experiments to cover the range of phenomena of interest. The first difficulty could be overcome if the research community were to support an online web based database. The second difficulty can be greatly reduced by automating procedures to set up and run simulations of similar types of experiments. Moreover, automated testing would be greatly facilitated if the data files obtained from a database were in a standard format that contained key experimental parameters as meta-data in a header to the data file. To illustrate our approach to V and V, we have developed a high explosive database (HED) at LANL. It now contains a large number of shock initiation experiments. Utilizing the header information in a data file from HED, we have written scripts to generate an input file for a hydro code
Mathematical Modelling Approach in Mathematics Education
Arseven, Ayla
2015-01-01
The topic of models and modeling has come to be important for science and mathematics education in recent years. The topic of "Modeling" topic is especially important for examinations such as PISA which is conducted at an international level and measures a student's success in mathematics. Mathematical modeling can be defined as using…
A reservoir simulation approach for modeling of naturally fractured reservoirs
Directory of Open Access Journals (Sweden)
H. Mohammadi
2012-12-01
Full Text Available In this investigation, the Warren and Root model proposed for the simulation of naturally fractured reservoir was improved. A reservoir simulation approach was used to develop a 2D model of a synthetic oil reservoir. Main rock properties of each gridblock were defined for two different types of gridblocks called matrix and fracture gridblocks. These two gridblocks were different in porosity and permeability values which were higher for fracture gridblocks compared to the matrix gridblocks. This model was solved using the implicit finite difference method. Results showed an improvement in the Warren and Root model especially in region 2 of the semilog plot of pressure drop versus time, which indicated a linear transition zone with no inflection point as predicted by other investigators. Effects of fracture spacing, fracture permeability, fracture porosity, matrix permeability and matrix porosity on the behavior of a typical naturally fractured reservoir were also presented.
A Multivariate Approach to Functional Neuro Modeling
DEFF Research Database (Denmark)
Mørch, Niels J.S.
1998-01-01
by the application of linear and more flexible, nonlinear microscopic regression models to a real-world dataset. The dependency of model performance, as quantified by generalization error, on model flexibility and training set size is demonstrated, leading to the important realization that no uniformly optimal model......, provides the basis for a generalization theoretical framework relating model performance to model complexity and dataset size. Briefly summarized the major topics discussed in the thesis include: - An introduction of the representation of functional datasets by pairs of neuronal activity patterns...... exists. - Model visualization and interpretation techniques. The simplicity of this task for linear models contrasts the difficulties involved when dealing with nonlinear models. Finally, a visualization technique for nonlinear models is proposed. A single observation emerges from the thesis...
Directory of Open Access Journals (Sweden)
Merler Stefano
2010-06-01
Full Text Available Abstract Background In recent years large-scale computational models for the realistic simulation of epidemic outbreaks have been used with increased frequency. Methodologies adapt to the scale of interest and range from very detailed agent-based models to spatially-structured metapopulation models. One major issue thus concerns to what extent the geotemporal spreading pattern found by different modeling approaches may differ and depend on the different approximations and assumptions used. Methods We provide for the first time a side-by-side comparison of the results obtained with a stochastic agent-based model and a structured metapopulation stochastic model for the progression of a baseline pandemic event in Italy, a large and geographically heterogeneous European country. The agent-based model is based on the explicit representation of the Italian population through highly detailed data on the socio-demographic structure. The metapopulation simulations use the GLobal Epidemic and Mobility (GLEaM model, based on high-resolution census data worldwide, and integrating airline travel flow data with short-range human mobility patterns at the global scale. The model also considers age structure data for Italy. GLEaM and the agent-based models are synchronized in their initial conditions by using the same disease parameterization, and by defining the same importation of infected cases from international travels. Results The results obtained show that both models provide epidemic patterns that are in very good agreement at the granularity levels accessible by both approaches, with differences in peak timing on the order of a few days. The relative difference of the epidemic size depends on the basic reproductive ratio, R0, and on the fact that the metapopulation model consistently yields a larger incidence than the agent-based model, as expected due to the differences in the structure in the intra-population contact pattern of the approaches. The age
A Partial Join Approach for Mining Co-Location Patterns: A Summary of Results
National Research Council Canada - National Science Library
Yoo, Jin S; Shekhar, Shashi
2005-01-01
.... They propose a novel partial-join approach for mining co-location patterns efficiently. It transactionizes continuous spatial data while keeping track of the spatial information not modeled by transactions...
Verification of aseismic design model by using experimental results
International Nuclear Information System (INIS)
Mizuno, N.; Sugiyama, N.; Suzuki, T.; Shibata, Y.; Miura, K.; Miyagawa, N.
1985-01-01
A lattice model is applied as an analysis model for an aseismic design of the Hamaoka nuclear reactor building. With object to verify an availability of this design model, two reinforced concrete blocks are constructed on the ground and the forced vibration tests are carried out. The test results are well followed by simulation analysis using the lattice model. Damping value of the ground obtained from the test is more conservative than the design value. (orig.)
Implementing a stepped-care approach in primary care: results of a qualitative study
Directory of Open Access Journals (Sweden)
Franx Gerdien
2012-01-01
Full Text Available Abstract Background Since 2004, 'stepped-care models' have been adopted in several international evidence-based clinical guidelines to guide clinicians in the organisation of depression care. To enhance the adoption of this new treatment approach, a Quality Improvement Collaborative (QIC was initiated in the Netherlands. Methods Alongside the QIC, an intervention study using a controlled before-and-after design was performed. Part of the study was a process evaluation, utilizing semi-structured group interviews, to provide insight into the perceptions of the participating clinicians on the implementation of stepped care for depression into their daily routines. Participants were primary care clinicians, specialist clinicians, and other healthcare staff from eight regions in the Netherlands. Analysis was supported by the Normalisation Process Theory (NPT. Results The introduction of a stepped-care model for depression to primary care teams within the context of a depression QIC was generally well received by participating clinicians. All three elements of the proposed stepped-care model (patient differentiation, stepped-care treatment, and outcome monitoring, were translated and introduced locally. Clinicians reported changes in terms of learning how to differentiate between patient groups and different levels of care, changing antidepressant prescribing routines as a consequence of having a broader treatment package to offer to their patients, and better working relationships with patients and colleagues. A complex range of factors influenced the implementation process. Facilitating factors were the stepped-care model itself, the structured team meetings (part of the QIC method, and the positive reaction from patients to stepped care. The differing views of depression and depression care within multidisciplinary health teams, lack of resources, and poor information systems hindered the rapid introduction of the stepped-care model. The NPT
Stability of Rotor Systems: A Complex Modelling Approach
DEFF Research Database (Denmark)
Kliem, Wolfhard; Pommer, Christian; Stoustrup, Jakob
1996-01-01
with the results of the classical approach using Rayleighquotients. Several rotor systems are tested: a simple Laval rotor, a Laval rotor with additional elasticity and damping in thr bearings, and a number of rotor systems with complex symmetric 4x4 randomly generated matrices.......A large class of rotor systems can be modelled by a complex matrix differential equation of secondorder. The angular velocity of the rotor plays the role of a parameter. We apply the Lyapunov matrix equation in a complex setting and prove two new stability results which are compared...
Anzhelika D. Tsymbalaru
2010-01-01
In the paper the scientific approaches to modeling of innovation educational environment of a general educational institution – system (analysis of object, process and result of modeling as system objects), activity (organizational and psychological structure) and synergetic (aspects and principles).
Ajelli, Marco; Gonçalves, Bruno; Balcan, Duygu; Colizza, Vittoria; Hu, Hao; Ramasco, José J; Merler, Stefano; Vespignani, Alessandro
2010-06-29
In recent years large-scale computational models for the realistic simulation of epidemic outbreaks have been used with increased frequency. Methodologies adapt to the scale of interest and range from very detailed agent-based models to spatially-structured metapopulation models. One major issue thus concerns to what extent the geotemporal spreading pattern found by different modeling approaches may differ and depend on the different approximations and assumptions used. We provide for the first time a side-by-side comparison of the results obtained with a stochastic agent-based model and a structured metapopulation stochastic model for the progression of a baseline pandemic event in Italy, a large and geographically heterogeneous European country. The agent-based model is based on the explicit representation of the Italian population through highly detailed data on the socio-demographic structure. The metapopulation simulations use the GLobal Epidemic and Mobility (GLEaM) model, based on high-resolution census data worldwide, and integrating airline travel flow data with short-range human mobility patterns at the global scale. The model also considers age structure data for Italy. GLEaM and the agent-based models are synchronized in their initial conditions by using the same disease parameterization, and by defining the same importation of infected cases from international travels. The results obtained show that both models provide epidemic patterns that are in very good agreement at the granularity levels accessible by both approaches, with differences in peak timing on the order of a few days. The relative difference of the epidemic size depends on the basic reproductive ratio, R0, and on the fact that the metapopulation model consistently yields a larger incidence than the agent-based model, as expected due to the differences in the structure in the intra-population contact pattern of the approaches. The age breakdown analysis shows that similar attack rates are
Uncertainty in biology a computational modeling approach
Gomez-Cabrero, David
2016-01-01
Computational modeling of biomedical processes is gaining more and more weight in the current research into the etiology of biomedical problems and potential treatment strategies. Computational modeling allows to reduce, refine and replace animal experimentation as well as to translate findings obtained in these experiments to the human background. However these biomedical problems are inherently complex with a myriad of influencing factors, which strongly complicates the model building and validation process. This book wants to address four main issues related to the building and validation of computational models of biomedical processes: Modeling establishment under uncertainty Model selection and parameter fitting Sensitivity analysis and model adaptation Model predictions under uncertainty In each of the abovementioned areas, the book discusses a number of key-techniques by means of a general theoretical description followed by one or more practical examples. This book is intended for graduate stude...
Social Network Analysis and Nutritional Behavior: An Integrated Modeling Approach.
Senior, Alistair M; Lihoreau, Mathieu; Buhl, Jerome; Raubenheimer, David; Simpson, Stephen J
2016-01-01
Animals have evolved complex foraging strategies to obtain a nutritionally balanced diet and associated fitness benefits. Recent research combining state-space models of nutritional geometry with agent-based models (ABMs), show how nutrient targeted foraging behavior can also influence animal social interactions, ultimately affecting collective dynamics and group structures. Here we demonstrate how social network analyses can be integrated into such a modeling framework and provide a practical analytical tool to compare experimental results with theory. We illustrate our approach by examining the case of nutritionally mediated dominance hierarchies. First we show how nutritionally explicit ABMs that simulate the emergence of dominance hierarchies can be used to generate social networks. Importantly the structural properties of our simulated networks bear similarities to dominance networks of real animals (where conflicts are not always directly related to nutrition). Finally, we demonstrate how metrics from social network analyses can be used to predict the fitness of agents in these simulated competitive environments. Our results highlight the potential importance of nutritional mechanisms in shaping dominance interactions in a wide range of social and ecological contexts. Nutrition likely influences social interactions in many species, and yet a theoretical framework for exploring these effects is currently lacking. Combining social network analyses with computational models from nutritional ecology may bridge this divide, representing a pragmatic approach for generating theoretical predictions for nutritional experiments.
Steel Containment Vessel Model Test: Results and Evaluation
Energy Technology Data Exchange (ETDEWEB)
Costello, J.F.; Hashimote, T.; Hessheimer, M.F.; Luk, V.K.
1999-03-01
A high pressure test of the steel containment vessel (SCV) model was conducted on December 11-12, 1996 at Sandia National Laboratories, Albuquerque, NM, USA. The test model is a mixed-scaled model (1:10 in geometry and 1:4 in shell thickness) of an improved Mark II boiling water reactor (BWR) containment. A concentric steel contact structure (CS), installed over the SCV model and separated at a nominally uniform distance from it, provided a simplified representation of a reactor shield building in the actual plant. The SCV model and contact structure were instrumented with strain gages and displacement transducers to record the deformation behavior of the SCV model during the high pressure test. This paper summarizes the conduct and the results of the high pressure test and discusses the posttest metallurgical evaluation results on specimens removed from the SCV model.
Relaxed memory models: an operational approach
Boudol , Gérard; Petri , Gustavo
2009-01-01
International audience; Memory models define an interface between programs written in some language and their implementation, determining which behaviour the memory (and thus a program) is allowed to have in a given model. A minimal guarantee memory models should provide to the programmer is that well-synchronized, that is, data-race free code has a standard semantics. Traditionally, memory models are defined axiomatically, setting constraints on the order in which memory operations are allow...
Numerical modelling approach for mine backfill
Indian Academy of Sciences (India)
... of mine backfill material needs special attention as the numerical model must behave realistically and in accordance with the site conditions. This paper discusses a numerical modelling strategy for modelling mine backfill material. Themodelling strategy is studied using a case study mine from Canadian mining industry.
Identifiability Results for Several Classes of Linear Compartment Models.
Meshkat, Nicolette; Sullivant, Seth; Eisenberg, Marisa
2015-08-01
Identifiability concerns finding which unknown parameters of a model can be estimated, uniquely or otherwise, from given input-output data. If some subset of the parameters of a model cannot be determined given input-output data, then we say the model is unidentifiable. In this work, we study linear compartment models, which are a class of biological models commonly used in pharmacokinetics, physiology, and ecology. In past work, we used commutative algebra and graph theory to identify a class of linear compartment models that we call identifiable cycle models, which are unidentifiable but have the simplest possible identifiable functions (so-called monomial cycles). Here we show how to modify identifiable cycle models by adding inputs, adding outputs, or removing leaks, in such a way that we obtain an identifiable model. We also prove a constructive result on how to combine identifiable models, each corresponding to strongly connected graphs, into a larger identifiable model. We apply these theoretical results to several real-world biological models from physiology, cell biology, and ecology.
Comparison of Calculational Results from Different Spent Nuclear Fuel (SNF) Crumbling Approaches
Energy Technology Data Exchange (ETDEWEB)
PIEPHO, M.G.
2000-01-25
Several safety basis cases or scenarios using three different fuel crumbling or degradation approaches were simulated with a modified HANSF Code. Results of simulations are compared and discussed. The conclusion is that the safety basis fuel reaction enhancement factors are conservative and bound other fuel crumbling approaches for the results of interest.
Policy harmonized approach for the EU agricultural sector modelling
Directory of Open Access Journals (Sweden)
G. SALPUTRA
2008-12-01
Full Text Available Policy harmonized (PH approach allows for the quantitative assessment of the impact of various elements of EU CAP direct support schemes, where the production effects of direct payments are accounted through reaction prices formed by producer price and policy price add-ons. Using the AGMEMOD model the impacts of two possible EU agricultural policy scenarios upon beef production have been analysed full decoupling with a switch from historical to regional Single Payment scheme or alternatively with re-distribution of country direct payment envelopes via introduction of EU-wide flat area payment. The PH approach, by systematizing and harmonizing the management and use of policy data, ensures that projected differential policy impacts arising from changes in common EU policies reflect the likely actual differential impact as opposed to differences in how common policies are implemented within analytical models. In the second section of the paper the AGMEMOD models structure is explained. The policy harmonized evaluation method is presented in the third section. Results from an application of the PH approach are presented and discussed in the papers penultimate section, while section 5 concludes.;
A multi-region approach to modeling subsurface flow
International Nuclear Information System (INIS)
Gwo, J.P.; Yeh, G.T.; Wilson, G.V.
1990-01-01
In this approach the media are assumed to contain n pore-regions at any physical point. Each region has different pore size and hydrologic parameters. Inter-region exchange is approximated by a linear transfer process. Based on the mass balance principle, a system of equations governing the flow and mass exchange in structured or aggregated soils is derived. This system of equations is coupled through linear transfer terms representing the interchange among different pore regions. A numerical MUlti-Region Flow (MURF) model, using the Galerkin finite element method to facilitate the treatment of local and field-scale heterogeneities, is developed to solve the system of equations. A sparse matrix solver is used to solve the resulting matrix equation, which makes the application of MURF to large field problems feasible in terms of CPU time and storage limitations. MURF is first verified by applying it to a ponding infiltration problem over a hill slope, which is a single-region problem and has been previously simulated by a single-region model. Very good agreement is obtained between the results from the two different models. The MURF code is thus partially verified. It is then applied to a two-region fractured medium to investigate the effects of multi-region approach on the flow field. The results are comparable to that obtained by other investigators. (Author) (15 refs., 6 figs., tab.)
Virtuous organization: A structural equation modeling approach
Directory of Open Access Journals (Sweden)
Majid Zamahani
2013-02-01
Full Text Available For years, the idea of virtue was unfavorable among researchers and virtues were traditionally considered as culture-specific, relativistic and they were supposed to be associated with social conservatism, religious or moral dogmatism, and scientific irrelevance. Virtue and virtuousness have been recently considered seriously among organizational researchers. The proposed study of this paper examines the relationships between leadership, organizational culture, human resource, structure and processes, care for community and virtuous organization. Structural equation modeling is employed to investigate the effects of each variable on other components. The data used in this study consists of questionnaire responses from employees in Payam e Noor University in Yazd province. A total of 250 questionnaires were sent out and a total of 211 valid responses were received. Our results have revealed that all the five variables have positive and significant impacts on virtuous organization. Among the five variables, organizational culture has the most direct impact (0.80 and human resource has the most total impact (0.844 on virtuous organization.
Hauduc, H; Rieger, L; Takács, I; Héduit, A; Vanrolleghem, P A; Gillot, S
2010-01-01
The quality of simulation results can be significantly affected by errors in the published model (typing, inconsistencies, gaps or conceptual errors) and/or in the underlying numerical model description. Seven of the most commonly used activated sludge models have been investigated to point out the typing errors, inconsistencies and gaps in the model publications: ASM1; ASM2d; ASM3; ASM3 + Bio-P; ASM2d + TUD; New General; UCTPHO+. A systematic approach to verify models by tracking typing errors and inconsistencies in model development and software implementation is proposed. Then, stoichiometry and kinetic rate expressions are checked for each model and the errors found are reported in detail. An attached spreadsheet (see http://www.iwaponline.com/wst/06104/0898.pdf) provides corrected matrices with the calculations of all stoichiometric coefficients for the discussed biokinetic models and gives an example of proper continuity checks.
Results of the Marine Ice Sheet Model Intercomparison Project, MISMIP
Directory of Open Access Journals (Sweden)
F. Pattyn
2012-05-01
Full Text Available Predictions of marine ice-sheet behaviour require models that are able to robustly simulate grounding line migration. We present results of an intercomparison exercise for marine ice-sheet models. Verification is effected by comparison with approximate analytical solutions for flux across the grounding line using simplified geometrical configurations (no lateral variations, no effects of lateral buttressing. Unique steady state grounding line positions exist for ice sheets on a downward sloping bed, while hysteresis occurs across an overdeepened bed, and stable steady state grounding line positions only occur on the downward-sloping sections. Models based on the shallow ice approximation, which does not resolve extensional stresses, do not reproduce the approximate analytical results unless appropriate parameterizations for ice flux are imposed at the grounding line. For extensional-stress resolving "shelfy stream" models, differences between model results were mainly due to the choice of spatial discretization. Moving grid methods were found to be the most accurate at capturing grounding line evolution, since they track the grounding line explicitly. Adaptive mesh refinement can further improve accuracy, including fixed grid models that generally perform poorly at coarse resolution. Fixed grid models, with nested grid representations of the grounding line, are able to generate accurate steady state positions, but can be inaccurate over transients. Only one full-Stokes model was included in the intercomparison, and consequently the accuracy of shelfy stream models as approximations of full-Stokes models remains to be determined in detail, especially during transients.
A multi-model ensemble approach to seabed mapping
Diesing, Markus; Stephens, David
2015-06-01
Seabed habitat mapping based on swath acoustic data and ground-truth samples is an emergent and active marine science discipline. Significant progress could be achieved by transferring techniques and approaches that have been successfully developed and employed in such fields as terrestrial land cover mapping. One such promising approach is the multiple classifier system, which aims at improving classification performance by combining the outputs of several classifiers. Here we present results of a multi-model ensemble applied to multibeam acoustic data covering more than 5000 km2 of seabed in the North Sea with the aim to derive accurate spatial predictions of seabed substrate. A suite of six machine learning classifiers (k-Nearest Neighbour, Support Vector Machine, Classification Tree, Random Forest, Neural Network and Naïve Bayes) was trained with ground-truth sample data classified into seabed substrate classes and their prediction accuracy was assessed with an independent set of samples. The three and five best performing models were combined to classifier ensembles. Both ensembles led to increased prediction accuracy as compared to the best performing single classifier. The improvements were however not statistically significant at the 5% level. Although the three-model ensemble did not perform significantly better than its individual component models, we noticed that the five-model ensemble did perform significantly better than three of the five component models. A classifier ensemble might therefore be an effective strategy to improve classification performance. Another advantage is the fact that the agreement in predicted substrate class between the individual models of the ensemble could be used as a measure of confidence. We propose a simple and spatially explicit measure of confidence that is based on model agreement and prediction accuracy.
Numerical modelling of carbonate platforms and reefs: approaches and opportunities
Energy Technology Data Exchange (ETDEWEB)
Dalmasso, H.; Montaggioni, L.F.; Floquet, M. [Universite de Provence, Marseille (France). Centre de Sedimentologie-Palaeontologie; Bosence, D. [Royal Holloway University of London, Egham (United Kingdom). Dept. of Geology
2001-07-01
This paper compares different computing procedures that have been utilized in simulating shallow-water carbonate platform development. Based on our geological knowledge we can usually give a rather accurate qualitative description of the mechanisms controlling geological phenomena. Further description requires the use of computer stratigraphic simulation models that allow quantitative evaluation and understanding of the complex interactions of sedimentary depositional carbonate systems. The roles of modelling include: (1) encouraging accuracy and precision in data collection and process interpretation (Watney et al., 1999); (2) providing a means to quantitatively test interpretations concerning the control of various mechanisms on producing sedimentary packages; (3) predicting or extrapolating results into areas of limited control; (4) gaining new insights regarding the interaction of parameters; (5) helping focus on future studies to resolve specific problems. This paper addresses two main questions, namely: (1) What are the advantages and disadvantages of various types of models? (2) How well do models perform? In this paper we compare and discuss the application of five numerical models: CARBONATE (Bosence and Waltham, 1990), FUZZIM (Nordlund, 1999), CARBPLAT (Bosscher, 1992), DYNACARB (Li et al., 1993), PHIL (Bowman, 1997) and SEDPAK (Kendall et al., 1991). The comparison, testing and evaluation of these models allow one to gain a better knowledge and understanding of controlling parameters of carbonate platform development, which are necessary for modelling. Evaluating numerical models, critically comparing results from models using different approaches, and pushing experimental tests to their limits, provide an effective vehicle to improve and develop new numerical models. A main feature of this paper is to closely compare the performance between two numerical models: a forward model (CARBONATE) and a fuzzy logic model (FUZZIM). These two models use common
A probabilistic approach to the drag-based model
Napoletano, Gianluca; Forte, Roberta; Moro, Dario Del; Pietropaolo, Ermanno; Giovannelli, Luca; Berrilli, Francesco
2018-02-01
The forecast of the time of arrival (ToA) of a coronal mass ejection (CME) to Earth is of critical importance for our high-technology society and for any future manned exploration of the Solar System. As critical as the forecast accuracy is the knowledge of its precision, i.e. the error associated to the estimate. We propose a statistical approach for the computation of the ToA using the drag-based model by introducing the probability distributions, rather than exact values, as input parameters, thus allowing the evaluation of the uncertainty on the forecast. We test this approach using a set of CMEs whose transit times are known, and obtain extremely promising results: the average value of the absolute differences between measure and forecast is 9.1h, and half of these residuals are within the estimated errors. These results suggest that this approach deserves further investigation. We are working to realize a real-time implementation which ingests the outputs of automated CME tracking algorithms as inputs to create a database of events useful for a further validation of the approach.
A tantalum strength model using a multiscale approach: version 2
Energy Technology Data Exchange (ETDEWEB)
Becker, R; Arsenlis, A; Hommes, G; Marian, J; Rhee, M; Yang, L H
2009-09-21
A continuum strength model for tantalum was developed in 2007 using a multiscale approach. This was our first attempt at connecting simulation results from atomistic to continuum length scales, and much was learned that we were not able to incorporate into the model at that time. The tantalum model described in this report represents a second cut at pulling together multiscale simulation results into a continuum model. Insight gained in creating previous multiscale models for tantalum and vanadium was used to guide the model construction and functional relations for the present model. While the basic approach follows that of the vanadium model, there are significant departures. Some of the recommendations from the vanadium report were followed, but not all. Results from several new analysis techniques have not yet been incorporated due to technical difficulties. Molecular dynamics simulations of single dislocation motion at several temperatures suggested that the thermal activation barrier was temperature dependent. This dependency required additional temperature functions be included within the assumed Arrhenius relation. The combination of temperature dependent functions created a complex model with a non unique parameterization and extra model constants. The added complexity had no tangible benefits. The recommendation was to abandon the strict Arrhenius form and create a simpler curve fit to the molecular dynamics data for shear stress versus dislocation velocity. Functions relating dislocation velocity and applied shear stress were constructed vor vanadium for both edge and screw dislocations. However, an attempt to formulate a robust continuum constitutive model for vanadium using both dislocation populations was unsuccessful; the level of coupling achieved was inadequate to constrain the dislocation evolution properly. Since the behavior of BCC materials is typically assumed to be dominated by screw dislocations, the constitutive relations were ultimately
Results on the symmetries of integrable fermionic models on chains
International Nuclear Information System (INIS)
Dolcini, F.; Montorsi, A.
2001-01-01
We investigate integrable fermionic models within the scheme of the graded quantum inverse scattering method, and prove that any symmetry imposed on the solution of the Yang-Baxter equation reflects on the constants of motion of the model; generalizations with respect to known results are discussed. This theorem is shown to be very effective when combined with the polynomial R-matrix technique (PRT): we apply both of them to the study of the extended Hubbard models, for which we find all the subcases enjoying several kinds of (super)symmetries. In particular, we derive a geometrical construction expressing any gl(2,1)-invariant model as a linear combination of EKS and U-supersymmetric models. Further, we use the PRT to obtain 32 integrable so(4)-invariant models. By joint use of the Sutherland's species technique and η-pairs construction we propose a general method to derive their physical features, and we provide some explicit results
Models Portability: Some Considerations about Transdisciplinary Approaches
Giuliani, Alessandro
Some critical issues about the relative portability of models and solutions across disciplinary barriers are discussed. The risks linked to the use of models and theories coming from different disciplines are evidentiated with a particular emphasis on biology. A metaphorical use of conceptual tools coming from other fields is suggested, together with the unescapable need to judge about the relative merits of a model on the basis of the amount of facts relative to the particular domain of application it explains. Some examples of metaphorical modeling coming from biochemistry and psychobiology are briefly discussed in order to clarify the above positions.
Nonlinear Modeling of the PEMFC Based On NNARX Approach
Shan-Jen Cheng; Te-Jen Chang; Kuang-Hsiung Tan; Shou-Ling Kuo
2015-01-01
Polymer Electrolyte Membrane Fuel Cell (PEMFC) is such a time-vary nonlinear dynamic system. The traditional linear modeling approach is hard to estimate structure correctly of PEMFC system. From this reason, this paper presents a nonlinear modeling of the PEMFC using Neural Network Auto-regressive model with eXogenous inputs (NNARX) approach. The multilayer perception (MLP) network is applied to evaluate the structure of the NNARX model of PEMFC. The validity and accurac...
A visual approach for modeling spatiotemporal relations
R.L. Guimarães (Rodrigo); C.S.S. Neto; L.F.G. Soares
2008-01-01
htmlabstractTextual programming languages have proven to be difficult to learn and to use effectively for many people. For this sake, visual tools can be useful to abstract the complexity of such textual languages, minimizing the specification efforts. In this paper we present a visual approach for
DIVERSE APPROACHES TO MODELLING THE ASSIMILATIVE ...
African Journals Online (AJOL)
This study evaluated the assimilative capacity of Ikpoba River using different approaches namely: homogeneous differential equation, ANOVA/Duncan Multiple rage test, first and second order differential equations, correlation analysis, Eigen values and eigenvectors, multiple linear regression, bootstrapping and far-field ...
Comparison of two novel approaches to model fibre reinforced concrete
Radtke, F.K.F.; Simone, A.; Sluys, L.J.
2009-01-01
We present two approaches to model fibre reinforced concrete. In both approaches, discrete fibre distributions and the behaviour of the fibre-matrix interface are explicitly considered. One approach employs the reaction forces from fibre to matrix while the other is based on the partition of unity
Authoring and verification of clinical guidelines: a model driven approach.
Pérez, Beatriz; Porres, Ivan
2010-08-01
The goal of this research is to provide a framework to enable authoring and verification of clinical guidelines. The framework is part of a larger research project aimed at improving the representation, quality and application of clinical guidelines in daily clinical practice. The verification process of a guideline is based on (1) model checking techniques to verify guidelines against semantic errors and inconsistencies in their definition, (2) combined with Model Driven Development (MDD) techniques, which enable us to automatically process manually created guideline specifications and temporal-logic statements to be checked and verified regarding these specifications, making the verification process faster and cost-effective. Particularly, we use UML statecharts to represent the dynamics of guidelines and, based on this manually defined guideline specifications, we use a MDD-based tool chain to automatically process them to generate the input model of a model checker. The model checker takes the resulted model together with the specific guideline requirements, and verifies whether the guideline fulfils such properties. The overall framework has been implemented as an Eclipse plug-in named GBDSSGenerator which, particularly, starting from the UML statechart representing a guideline, allows the verification of the guideline against specific requirements. Additionally, we have established a pattern-based approach for defining commonly occurring types of requirements in guidelines. We have successfully validated our overall approach by verifying properties in different clinical guidelines resulting in the detection of some inconsistencies in their definition. The proposed framework allows (1) the authoring and (2) the verification of clinical guidelines against specific requirements defined based on a set of property specification patterns, enabling non-experts to easily write formal specifications and thus easing the verification process. Copyright 2010 Elsevier Inc
Modeling drug- and chemical- induced hepatotoxicity with systems biology approaches
Directory of Open Access Journals (Sweden)
Sudin eBhattacharya
2012-12-01
Full Text Available We provide an overview of computational systems biology approaches as applied to the study of chemical- and drug-induced toxicity. The concept of ‘toxicity pathways’ is described in the context of the 2007 US National Academies of Science report, Toxicity testing in the 21st Century: A Vision and A Strategy. Pathway mapping and modeling based on network biology concepts are a key component of the vision laid out in this report for a more biologically-based analysis of dose-response behavior and the safety of chemicals and drugs. We focus on toxicity of the liver (hepatotoxicity – a complex phenotypic response with contributions from a number of different cell types and biological processes. We describe three case studies of complementary multi-scale computational modeling approaches to understand perturbation of toxicity pathways in the human liver as a result of exposure to environmental contaminants and specific drugs. One approach involves development of a spatial, multicellular virtual tissue model of the liver lobule that combines molecular circuits in individual hepatocytes with cell-cell interactions and blood-mediated transport of toxicants through hepatic sinusoids, to enable quantitative, mechanistic prediction of hepatic dose-response for activation of the AhR toxicity pathway. Simultaneously, methods are being developing to extract quantitative maps of intracellular signaling and transcriptional regulatory networks perturbed by environmental contaminants, using a combination of gene expression and genome-wide protein-DNA interaction data. A predictive physiological model (DILIsymTM to understand drug-induced liver injury (DILI, the most common adverse event leading to termination of clinical development programs and regulatory actions on drugs, is also described. The model initially focuses on reactive metabolite-induced DILI in response to administration of acetaminophen, and spans multiple biological scales.
Modeling Approaches for Describing Microbial Population Heterogeneity
DEFF Research Database (Denmark)
Lencastre Fernandes, Rita
in a computational (CFD) fluid dynamic model. The anaerobic Growth of a budding yeast population in a continuously run microbioreactor was used as example. The proposed integrated model describes the fluid flow, the local cell size and cell cycle position distributions, as well as the local concentrations of glucose...
A simplified approach to feedwater train modeling
International Nuclear Information System (INIS)
Ollat, X.; Smoak, R.A.
1990-01-01
This paper presents a method to simplify feedwater train models for power plants. A simple set of algebraic equations, based on mass and energy balances, is developed to replace complex representations of the components under certain assumptions. The method was tested and used to model the low pressure heaters of the Sequoyah Nuclear Plant in a larger simulation
A cascade modelling approach to flood extent estimation
Pedrozo-Acuña, Adrian; Rodríguez-Rincón, Juan Pablo; Breña-Naranjo, Agustin
2014-05-01
Recent efforts dedicated to the generation of new flood risk management strategies, have pointed out that a possible way forward for an improvement in this field relies on the reduction and quantification of uncertainties associated to the prediction system. With the purpose of reducing these uncertainties, this investigation follows a cascade modelling approach (meteorological - hydrological - 2D hydrodynamic) in combination with high-quality data (LiDAR, satellite imagery, precipitation), to study an extreme event registered last year in Mexico. The presented approach is useful for both, the characterisation of epistemic uncertainties and the generation of flood management strategies through probabilistic flood maps. Uncertainty is considered in both meteorological and hydrological models, and is propagated to a given flood extent as determined with a hydrodynamic model. Despite the methodology does not consider all the uncertainties that may be involved in the determination of a flooded area, it enables better understanding of the interaction between errors in the set-up of models and their propagation to a given result.
Artificial Life of Soybean Plant Growth Modeling Using Intelligence Approaches
Directory of Open Access Journals (Sweden)
Atris Suyantohadi
2010-03-01
Full Text Available The natural process on plant growth system has a complex system and it has could be developed on characteristic studied using intelligent approaches conducting with artificial life system. The approaches on examining the natural process on soybean (Glycine Max L.Merr plant growth have been analyzed and synthesized in these research through modeling using Artificial Neural Network (ANN and Lindenmayer System (L-System methods. Research aimed to design and to visualize plant growth modeling on the soybean varieties which these could help for studying botany of plant based on fertilizer compositions on plant growth with Nitrogen (N, Phosphor (P and Potassium (K. The soybean plant growth has been analyzed based on the treatments of plant fertilizer compositions in the experimental research to develop plant growth modeling. By using N, P, K fertilizer compositions, its capable result on the highest production 2.074 tons/hectares. Using these models, the simulation on artificial life for describing identification and visualization on the characteristic of soybean plant growth could be demonstrated and applied.
Modeling the cometary environment using a fluid approach
Shou, Yinsi
Comets are believed to have preserved the building material of the early solar system and to hold clues to the origin of life on Earth. Abundant remote observations of comets by telescopes and the in-situ measurements by a handful of space missions reveal that the cometary environments are complicated by various physical and chemical processes among the neutral gases and dust grains released from comets, cometary ions, and the solar wind in the interplanetary space. Therefore, physics-based numerical models are in demand to interpret the observational data and to deepen our understanding of the cometary environment. In this thesis, three models using a fluid approach, which include important physical and chemical processes underlying the cometary environment, have been developed to study the plasma, neutral gas, and the dust grains, respectively. Although models based on the fluid approach have limitations in capturing all of the correct physics for certain applications, especially for very low gas density environment, they are computationally much more efficient than alternatives. In the simulations of comet 67P/Churyumov-Gerasimenko at various heliocentric distances with a wide range of production rates, our multi-fluid cometary neutral gas model and multi-fluid cometary dust model have achieved comparable results to the Direct Simulation Monte Carlo (DSMC) model, which is based on a kinetic approach that is valid in all collisional regimes. Therefore, our model is a powerful alternative to the particle-based model, especially for some computationally intensive simulations. Capable of accounting for the varying heating efficiency under various physical conditions in a self-consistent way, the multi-fluid cometary neutral gas model is a good tool to study the dynamics of the cometary coma with different production rates and heliocentric distances. The modeled H2O expansion speeds reproduce the general trend and the speed's nonlinear dependencies of production rate
Quantitative versus qualitative modeling: a complementary approach in ecosystem study.
Bondavalli, C; Favilla, S; Bodini, A
2009-02-01
Natural disturbance or human perturbation act upon ecosystems by changing some dynamical parameters of one or more species. Foreseeing these modifications is necessary before embarking on an intervention: predictions may help to assess management options and define hypothesis for interventions. Models become valuable tools for studying and making predictions only when they capture types of interactions and their magnitude. Quantitative models are more precise and specific about a system, but require a large effort in model construction. Because of this very often ecological systems remain only partially specified and one possible approach to their description and analysis comes from qualitative modelling. Qualitative models yield predictions as directions of change in species abundance but in complex systems these predictions are often ambiguous, being the result of opposite actions exerted on the same species by way of multiple pathways of interactions. Again, to avoid such ambiguities one needs to know the intensity of all links in the system. One way to make link magnitude explicit in a way that can be used in qualitative analysis is described in this paper and takes advantage of another type of ecosystem representation: ecological flow networks. These flow diagrams contain the structure, the relative position and the connections between the components of a system, and the quantity of matter flowing along every connection. In this paper it is shown how these ecological flow networks can be used to produce a quantitative model similar to the qualitative counterpart. Analyzed through the apparatus of loop analysis this quantitative model yields predictions that are by no means ambiguous, solving in an elegant way the basic problem of qualitative analysis. The approach adopted in this work is still preliminary and we must be careful in its application.
The workshop on ecosystems modelling approaches for South ...
African Journals Online (AJOL)
roles played by models in the OMP approach, and raises questions about the costs of the data collection. (in particular) needed to apply a multispecies modelling approach in South African fisheries management. It then summarizes the deliberations of workshops held by the Scientific Committees of two international ma-.
Object-Oriented Approach to Modeling Units of Pneumatic Systems
Directory of Open Access Journals (Sweden)
Yu. V. Kyurdzhiev
2014-01-01
Full Text Available The article shows the relevance of the approaches to the object-oriented programming when modeling the pneumatic units (PU.Based on the analysis of the calculation schemes of aggregates pneumatic systems two basic objects, namely a cavity flow and a material point were highlighted.Basic interactions of objects are defined. Cavity-cavity interaction: ex-change of matter and energy with the flows of mass. Cavity-point interaction: force interaction, exchange of energy in the form of operation. Point-point in-teraction: force interaction, elastic interaction, inelastic interaction, and inter-vals of displacement.The authors have developed mathematical models of basic objects and interactions. Models and interaction of elements are implemented in the object-oriented programming.Mathematical models of elements of PU design scheme are implemented in derived from the base class. These classes implement the models of flow cavity, piston, diaphragm, short channel, diaphragm to be open by a given law, spring, bellows, elastic collision, inelastic collision, friction, PU stages with a limited movement, etc.A numerical integration of differential equations for the mathematical models of PU design scheme elements is based on the Runge-Kutta method of the fourth order. On request each class performs a tact of integration i.e. calcu-lation of the coefficient method.The paper presents an integration algorithm of the system of differential equations. All objects of the PU design scheme are placed in a unidirectional class list. Iterator loop cycle initiates the integration tact of all the objects in the list. One in four iteration makes a transition to the next step of integration. Calculation process stops when any object shows a shutdowns flag.The proposed approach was tested in the calculation of a number of PU designs. With regard to traditional approaches to modeling, the authors-proposed method features in easy enhancement, code reuse, high reliability
Wave-current interactions: model development and preliminary results
Mayet, Clement; Lyard, Florent; Ardhuin, Fabrice
2013-04-01
The coastal area concentrates many uses that require integrated management based on diagnostic and predictive tools to understand and anticipate the future of pollution from land or sea, and learn more about natural hazards at sea or activity on the coast. The realistic modelling of coastal hydrodynamics needs to take into account various processes which interact, including tides, surges, and sea state (Wolf [2008]). These processes act at different spatial scales. Unstructured-grid models have shown the ability to satisfy these needs, given that a good mesh resolution criterion is used. We worked on adding a sea state forcing in a hydrodynamic circulation model. The sea state model is the unstructured version of WAVEWATCH III c (Tolman [2008]) (which version is developed at IFREMER, Brest (Ardhuin et al. [2010]) ), and the hydrodynamic model is the 2D barotropic module of the unstructured-grid finite element model T-UGOm (Le Bars et al. [2010]). We chose to use the radiation stress approach (Longuet-Higgins and Stewart [1964]) to represent the effect of surface waves (wind waves and swell) in the barotropic model, as previously done by Mastenbroek et al. [1993]and others. We present here some validation of the model against academic cases : a 2D plane beach (Haas and Warner [2009]) and a simple bathymetric step with analytic solution for waves (Ardhuin et al. [2008]). In a second part we present realistic application in the Ushant Sea during extreme event. References Ardhuin, F., N. Rascle, and K. Belibassakis, Explicit wave-averaged primitive equations using a generalized Lagrangian mean, Ocean Modelling, 20 (1), 35-60, doi:10.1016/j.ocemod.2007.07.001, 2008. Ardhuin, F., et al., Semiempirical Dissipation Source Functions for Ocean Waves. Part I: Definition, Calibration, and Validation, J. Phys. Oceanogr., 40 (9), 1917-1941, doi:10.1175/2010JPO4324.1, 2010. Haas, K. A., and J. C. Warner, Comparing a quasi-3D to a full 3D nearshore circulation model: SHORECIRC and
A simple approach to modeling ductile failure.
Energy Technology Data Exchange (ETDEWEB)
Wellman, Gerald William
2012-06-01
Sandia National Laboratories has the need to predict the behavior of structures after the occurrence of an initial failure. In some cases determining the extent of failure, beyond initiation, is required, while in a few cases the initial failure is a design feature used to tailor the subsequent load paths. In either case, the ability to numerically simulate the initiation and propagation of failures is a highly desired capability. This document describes one approach to the simulation of failure initiation and propagation.
Advanced language modeling approaches, case study: Expert search
Hiemstra, Djoerd
2008-01-01
This tutorial gives a clear and detailed overview of advanced language modeling approaches and tools, including the use of document priors, translation models, relevance models, parsimonious models and expectation maximization training. Expert search will be used as a case study to explain the
Model predictive control approach for a CPAP-device
Directory of Open Access Journals (Sweden)
Scheel Mathias
2017-09-01
Full Text Available The obstructive sleep apnoea syndrome (OSAS is characterized by a collapse of the upper respiratory tract, resulting in a reduction of the blood oxygen- and an increase of the carbon dioxide (CO2 - concentration, which causes repeated sleep disruptions. The gold standard to treat the OSAS is the continuous positive airway pressure (CPAP therapy. The continuous pressure keeps the upper airway open and prevents the collapse of the upper respiratory tract and the pharynx. Most of the available CPAP-devices cannot maintain the pressure reference [1]. In this work a model predictive control approach is provided. This control approach has the possibility to include the patient’s breathing effort into the calculation of the control variable. Therefore a patient-individualized control strategy can be developed.
Optimizing nitrogen fertilizer use: Current approaches and simulation models
International Nuclear Information System (INIS)
Baethgen, W.E.
2000-01-01
Nitrogen (N) is the most common limiting nutrient in agricultural systems throughout the world. Crops need sufficient available N to achieve optimum yields and adequate grain-protein content. Consequently, sub-optimal rates of N fertilizers typically cause lower economical benefits for farmers. On the other hand, excessive N fertilizer use may result in environmental problems such as nitrate contamination of groundwater and emission of N 2 O and NO. In spite of the economical and environmental importance of good N fertilizer management, the development of optimum fertilizer recommendations is still a major challenge in most agricultural systems. This article reviews the approaches most commonly used for making N recommendations: expected yield level, soil testing and plant analysis (including quick tests). The paper introduces the application of simulation models that complement traditional approaches, and includes some examples of current applications in Africa and South America. (author)
Anomalous superconductivity in the tJ model; moment approach
DEFF Research Database (Denmark)
Sørensen, Mads Peter; Rodriguez-Nunez, J.J.
1997-01-01
By extending the moment approach of Nolting (Z, Phys, 225 (1972) 25) in the superconducting phase, we have constructed the one-particle spectral functions (diagonal and off-diagonal) for the tJ model in any dimensions. We propose that both the diagonal and the off-diagonal spectral functions...... Hartree shift which in the end result enlarges the bandwidth of the free carriers allowing us to take relative high values of J/t and allowing superconductivity to live in the T-c-rho phase diagram, in agreement with numerical calculations in a cluster, We have calculated the static spin susceptibility......, chi(T), and the specific heat, C-v(T), within the moment approach. We find that all the relevant physical quantities show the signature of superconductivity at T-c in the form of kinks (anomalous behavior) or jumps, for low density, in agreement with recent published literature, showing a generic...
Chemotaxis: A Multi-Scale Modeling Approach
Bhowmik, Arpan
We are attempting to build a working simulation of population level self-organization in dictyostelium discoideum cells by combining existing models for chemo-attractant production and detection, along with phenomenological motility models. Our goal is to create a computationally-viable model-framework within which a population of cells can self-generate chemo-attractant waves and self-organize based on the directional cues of those waves. The work is a direct continuation of our previous work published in Physical Biology titled ``Excitable waves and direction-sensing in Dictyostelium Discoideum: steps towards a chemotaxis model''. This is a work in progress, no official draft/paper exists yet.
An Integrated Approach to Modeling Evacuation Behavior
2011-02-01
A spate of recent hurricanes and other natural disasters have drawn a lot of attention to the evacuation decision of individuals. Here we focus on evacuation models that incorporate two economic phenomena that seem to be increasingly important in exp...
Engineering approach to model and compute electric power markets settlements
International Nuclear Information System (INIS)
Kumar, J.; Petrov, V.
2006-01-01
Back-office accounting settlement activities are an important part of market operations in Independent System Operator (ISO) organizations. A potential way to measure ISO market design correctness is to analyze how well market price signals create incentives or penalties for creating an efficient market to achieve market design goals. Market settlement rules are an important tool for implementing price signals which are fed back to participants via the settlement activities of the ISO. ISO's are currently faced with the challenge of high volumes of data resulting from the increasing size of markets and ever-changing market designs, as well as the growing complexity of wholesale energy settlement business rules. This paper analyzed the problem and presented a practical engineering solution using an approach based on mathematical formulation and modeling of large scale calculations. The paper also presented critical comments on various differences in settlement design approaches to electrical power market design, as well as further areas of development. The paper provided a brief introduction to the wholesale energy market settlement systems and discussed problem formulation. An actual settlement implementation framework and discussion of the results and conclusions were also presented. It was concluded that a proper engineering approach to this domain can yield satisfying results by formalizing wholesale energy settlements. Significant improvements were observed in the initial preparation phase, scoping and effort estimation, implementation and testing. 5 refs., 2 figs
Challenges and opportunities for integrating lake ecosystem modelling approaches
Mooij, Wolf M.; Trolle, Dennis; Jeppesen, Erik; Arhonditsis, George; Belolipetsky, Pavel V.; Chitamwebwa, Deonatus B.R.; Degermendzhy, Andrey G.; DeAngelis, Donald L.; Domis, Lisette N. De Senerpont; Downing, Andrea S.; Elliott, J. Alex; Ruberto, Carlos Ruberto; Gaedke, Ursula; Genova, Svetlana N.; Gulati, Ramesh D.; Hakanson, Lars; Hamilton, David P.; Hipsey, Matthew R.; Hoen, Jochem 't; Hulsmann, Stephan; Los, F. Hans; Makler-Pick, Vardit; Petzoldt, Thomas; Prokopkin, Igor G.; Rinke, Karsten; Schep, Sebastiaan A.; Tominaga, Koji; Van Dam, Anne A.; Van Nes, Egbert H.; Wells, Scott A.; Janse, Jan H.
2010-01-01
A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others ('reinventing the wheel'). The other challenge is to avoid focusing on only one type of model, while ignoring new and diverse approaches that have become available ('having tunnel vision'). In this paper, we aim at improving the awareness of existing models and knowledge of concurrent approaches in lake ecosystem modelling, without covering all possible model tools and avenues. First, we present a broad variety of modelling approaches. To illustrate these approaches, we give brief descriptions of rather arbitrarily selected sets of specific models. We deal with static models (steady state and regression models), complex dynamic models (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally dynamic models and minimal dynamic models. We also discuss a group of approaches that could all be classified as individual based: super-individual models (Piscator, Charisma), physiologically structured models, stage-structured models and trait-based models. We briefly mention genetic algorithms, neural networks, Kalman filters and fuzzy logic. Thereafter, we zoom in, as an in-depth example, on the multi-decadal development and application of the lake ecosystem model PCLake and related models (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). In the discussion, we argue that while the historical development of each approach and model is understandable given its 'leading principle', there are many opportunities for combining approaches. We take the point of view that a single 'right' approach does not exist and should not be strived for. Instead, multiple modelling approaches, applied concurrently to a given problem, can help develop an integrative
"Dispersion modeling approaches for near road | Science ...
Roadway design and roadside barriers can have significant effects on the dispersion of traffic-generated pollutants, especially in the near-road environment. Dispersion models that can accurately simulate these effects are needed to fully assess these impacts for a variety of applications. For example, such models can be useful for evaluating the mitigation potential of roadside barriers in reducing near-road exposures and their associated adverse health effects. Two databases, a tracer field study and a wind tunnel study, provide measurements used in the development and/or validation of algorithms to simulate dispersion in the presence of noise barriers. The tracer field study was performed in Idaho Falls, ID, USA with a 6-m noise barrier and a finite line source in a variety of atmospheric conditions. The second study was performed in the meteorological wind tunnel at the US EPA and simulated line sources at different distances from a model noise barrier to capture the effect on emissions from individual lanes of traffic. In both cases, velocity and concentration measurements characterized the effect of the barrier on dispersion.This paper presents comparisons with the two datasets of the barrier algorithms implemented in two different dispersion models: US EPA’s R-LINE (a research dispersion modelling tool under development by the US EPA’s Office of Research and Development) and CERC’s ADMS model (ADMS-Urban). In R-LINE the physical features reveal
Modeling healthcare authorization and claim submissions using the openEHR dual-model approach
2011-01-01
Background The TISS standard is a set of mandatory forms and electronic messages for healthcare authorization and claim submissions among healthcare plans and providers in Brazil. It is not based on formal models as the new generation of health informatics standards suggests. The objective of this paper is to model the TISS in terms of the openEHR archetype-based approach and integrate it into a patient-centered EHR architecture. Methods Three approaches were adopted to model TISS. In the first approach, a set of archetypes was designed using ENTRY subclasses. In the second one, a set of archetypes was designed using exclusively ADMIN_ENTRY and CLUSTERs as their root classes. In the third approach, the openEHR ADMIN_ENTRY is extended with classes designed for authorization and claim submissions, and an ISM_TRANSITION attribute is added to the COMPOSITION class. Another set of archetypes was designed based on this model. For all three approaches, templates were designed to represent the TISS forms. Results The archetypes based on the openEHR RM (Reference Model) can represent all TISS data structures. The extended model adds subclasses and an attribute to the COMPOSITION class to represent information on authorization and claim submissions. The archetypes based on all three approaches have similar structures, although rooted in different classes. The extended openEHR RM model is more semantically aligned with the concepts involved in a claim submission, but may disrupt interoperability with other systems and the current tools must be adapted to deal with it. Conclusions Modeling the TISS standard by means of the openEHR approach makes it aligned with ISO recommendations and provides a solid foundation on which the TISS can evolve. Although there are few administrative archetypes available, the openEHR RM is expressive enough to represent the TISS standard. This paper focuses on the TISS but its results may be extended to other billing processes. A complete
Modeling healthcare authorization and claim submissions using the openEHR dual-model approach
Directory of Open Access Journals (Sweden)
Freire Sergio M
2011-10-01
Full Text Available Abstract Background The TISS standard is a set of mandatory forms and electronic messages for healthcare authorization and claim submissions among healthcare plans and providers in Brazil. It is not based on formal models as the new generation of health informatics standards suggests. The objective of this paper is to model the TISS in terms of the openEHR archetype-based approach and integrate it into a patient-centered EHR architecture. Methods Three approaches were adopted to model TISS. In the first approach, a set of archetypes was designed using ENTRY subclasses. In the second one, a set of archetypes was designed using exclusively ADMIN_ENTRY and CLUSTERs as their root classes. In the third approach, the openEHR ADMIN_ENTRY is extended with classes designed for authorization and claim submissions, and an ISM_TRANSITION attribute is added to the COMPOSITION class. Another set of archetypes was designed based on this model. For all three approaches, templates were designed to represent the TISS forms. Results The archetypes based on the openEHR RM (Reference Model can represent all TISS data structures. The extended model adds subclasses and an attribute to the COMPOSITION class to represent information on authorization and claim submissions. The archetypes based on all three approaches have similar structures, although rooted in different classes. The extended openEHR RM model is more semantically aligned with the concepts involved in a claim submission, but may disrupt interoperability with other systems and the current tools must be adapted to deal with it. Conclusions Modeling the TISS standard by means of the openEHR approach makes it aligned with ISO recommendations and provides a solid foundation on which the TISS can evolve. Although there are few administrative archetypes available, the openEHR RM is expressive enough to represent the TISS standard. This paper focuses on the TISS but its results may be extended to other billing
Vertically-integrated Approaches for Carbon Sequestration Modeling
Bandilla, K.; Celia, M. A.; Guo, B.
2015-12-01
Carbon capture and sequestration (CCS) is being considered as an approach to mitigate anthropogenic CO2 emissions from large stationary sources such as coal fired power plants and natural gas processing plants. Computer modeling is an essential tool for site design and operational planning as it allows prediction of the pressure response as well as the migration of both CO2 and brine in the subsurface. Many processes, such as buoyancy, hysteresis, geomechanics and geochemistry, can have important impacts on the system. While all of the processes can be taken into account simultaneously, the resulting models are computationally very expensive and require large numbers of parameters which are often uncertain or unknown. In many cases of practical interest, the computational and data requirements can be reduced by choosing a smaller domain and/or by neglecting or simplifying certain processes. This leads to a series of models with different complexity, ranging from coupled multi-physics, multi-phase three-dimensional models to semi-analytical single-phase models. Under certain conditions the three-dimensional equations can be integrated in the vertical direction, leading to a suite of two-dimensional multi-phase models, termed vertically-integrated models. These models are either solved numerically or simplified further (e.g., assumption of vertical equilibrium) to allow analytical or semi-analytical solutions. This presentation focuses on how different vertically-integrated models have been applied to the simulation of CO2 and brine migration during CCS projects. Several example sites, such as the Illinois Basin and the Wabamun Lake region of the Alberta Basin, are discussed to show how vertically-integrated models can be used to gain understanding of CCS operations.
Hyten, Cloyd
2009-01-01
Current Organizational Behavior Management (OBM) research and practice may be characterized as either behavior focused or results focused. These two approaches stem from different origins and have different characteristics. The behavior-focused approach stems from applied behavior analysis (ABA) methods and emphasizes direct observation of and…
Leader communication approaches and patient safety: An integrated model.
Mattson, Malin; Hellgren, Johnny; Göransson, Sara
2015-06-01
Leader communication is known to influence a number of employee behaviors. When it comes to the relationship between leader communication and safety, the evidence is more scarce and ambiguous. The aim of the present study is to investigate whether and in what way leader communication relates to safety outcomes. The study examines two leader communication approaches: leader safety priority communication and feedback to subordinates. These approaches were assumed to affect safety outcomes via different employee behaviors. Questionnaire data, collected from 221 employees at two hospital wards, were analyzed using structural equation modeling. The two examined communication approaches were both positively related to safety outcomes, although leader safety priority communication was mediated by employee compliance and feedback communication by organizational citizenship behaviors. The findings suggest that leader communication plays a vital role in improving organizational and patient safety and that different communication approaches seem to positively affect different but equally essential employee safety behaviors. The results highlights the necessity for leaders to engage in one-way communication of safety values as well as in more relational feedback communication with their subordinates in order to enhance patient safety. Copyright © 2015 Elsevier Ltd. and National Safety Council. Published by Elsevier Ltd. All rights reserved.
A chain reaction approach to modelling gene pathways.
Cheng, Gary C; Chen, Dung-Tsa; Chen, James J; Soong, Seng-Jaw; Lamartiniere, Coral; Barnes, Stephen
2012-08-01
BACKGROUND: Of great interest in cancer prevention is how nutrient components affect gene pathways associated with the physiological events of puberty. Nutrient-gene interactions may cause changes in breast or prostate cells and, therefore, may result in cancer risk later in life. Analysis of gene pathways can lead to insights about nutrient-gene interactions and the development of more effective prevention approaches to reduce cancer risk. To date, researchers have relied heavily upon experimental assays (such as microarray analysis, etc.) to identify genes and their associated pathways that are affected by nutrient and diets. However, the vast number of genes and combinations of gene pathways, coupled with the expense of the experimental analyses, has delayed the progress of gene-pathway research. The development of an analytical approach based on available test data could greatly benefit the evaluation of gene pathways, and thus advance the study of nutrient-gene interactions in cancer prevention. In the present study, we have proposed a chain reaction model to simulate gene pathways, in which the gene expression changes through the pathway are represented by the species undergoing a set of chemical reactions. We have also developed a numerical tool to solve for the species changes due to the chain reactions over time. Through this approach we can examine the impact of nutrient-containing diets on the gene pathway; moreover, transformation of genes over time with a nutrient treatment can be observed numerically, which is very difficult to achieve experimentally. We apply this approach to microarray analysis data from an experiment which involved the effects of three polyphenols (nutrient treatments), epigallo-catechin-3-O-gallate (EGCG), genistein, and resveratrol, in a study of nutrient-gene interaction in the estrogen synthesis pathway during puberty. RESULTS: In this preliminary study, the estrogen synthesis pathway was simulated by a chain reaction model. By
Numerical results for near surface time domain electromagnetic exploration: a full waveform approach
Sun, H.; Li, K.; Li, X., Sr.; Liu, Y., Sr.; Wen, J., Sr.
2015-12-01
Time domain or Transient electromagnetic (TEM) survey including types with airborne, semi-airborne and ground play important roles in applicants such as geological surveys, ground water/aquifer assess [Meju et al., 2000; Cox et al., 2010], metal ore exploration [Yang and Oldenburg, 2012], prediction of water bearing structures in tunnels [Xue et al., 2007; Sun et al., 2012], UXO exploration [Pasion et al., 2007; Gasperikova et al., 2009] etc. The common practice is introducing a current into a transmitting (Tx) loop and acquire the induced electromagnetic field after the current is cut off [Zhdanov and Keller, 1994]. The current waveforms are different depending on instruments. Rectangle is the most widely used excitation current source especially in ground TEM. Triangle and half sine are commonly used in airborne and semi-airborne TEM investigation. In most instruments, only the off time responses are acquired and used in later analysis and data inversion. Very few airborne instruments acquire the on time and off time responses together. Although these systems acquire the on time data, they usually do not use them in the interpretation.This abstract shows a novel full waveform time domain electromagnetic method and our recent modeling results. The benefits comes from our new algorithm in modeling full waveform time domain electromagnetic problems. We introduced the current density into the Maxwell's equation as the transmitting source. This approach allows arbitrary waveforms, such as triangle, half-sine, trapezoidal waves or scatter record from equipment, being used in modeling. Here, we simulate the establishing and induced diffusion process of the electromagnetic field in the earth. The traditional time domain electromagnetic with pure secondary fields can also be extracted from our modeling results. The real time responses excited by a loop source can be calculated using the algorithm. We analyze the full time gates responses of homogeneous half space and two
Predicting future glacial lakes in Austria using different modelling approaches
Otto, Jan-Christoph; Helfricht, Kay; Prasicek, Günther; Buckel, Johannes; Keuschnig, Markus
2017-04-01
Glacier retreat is one of the most apparent consequences of temperature rise in the 20th and 21th centuries in the European Alps. In Austria, more than 240 new lakes have formed in glacier forefields since the Little Ice Age. A similar signal is reported from many mountain areas worldwide. Glacial lakes can constitute important environmental and socio-economic impacts on high mountain systems including water resource management, sediment delivery, natural hazards, energy production and tourism. Their development significantly modifies the landscape configuration and visual appearance of high mountain areas. Knowledge on the location, number and extent of these future lakes can be used to assess potential impacts on high mountain geo-ecosystems and upland-lowland interactions. Information on new lakes is critical to appraise emerging threads and potentials for society. The recent development of regional ice thickness models and their combination with high resolution glacier surface data allows predicting the topography below current glaciers by subtracting ice thickness from glacier surface. Analyzing these modelled glacier bed surfaces reveals overdeepenings that represent potential locations for future lakes. In order to predict the location of future glacial lakes below recent glaciers in the Austrian Alps we apply different ice thickness models using high resolution terrain data and glacier outlines. The results are compared and validated with ice thickness data from geophysical surveys. Additionally, we run the models on three different glacier extents provided by the Austrian Glacier Inventories from 1969, 1998 and 2006. Results of this historical glacier extent modelling are compared to existing glacier lakes and discussed focusing on geomorphological impacts on lake evolution. We discuss model performance and observed differences in the results in order to assess the approach for a realistic prediction of future lake locations. The presentation delivers
New Approaches in Reuseable Booster System Life Cycle Cost Modeling
Zapata, Edgar
2013-01-01
This paper presents the results of a 2012 life cycle cost (LCC) study of hybrid Reusable Booster Systems (RBS) conducted by NASA Kennedy Space Center (KSC) and the Air Force Research Laboratory (AFRL). The work included the creation of a new cost estimating model and an LCC analysis, building on past work where applicable, but emphasizing the integration of new approaches in life cycle cost estimation. Specifically, the inclusion of industry processes/practices and indirect costs were a new and significant part of the analysis. The focus of LCC estimation has traditionally been from the perspective of technology, design characteristics, and related factors such as reliability. Technology has informed the cost related support to decision makers interested in risk and budget insight. This traditional emphasis on technology occurs even though it is well established that complex aerospace systems costs are mostly about indirect costs, with likely only partial influence in these indirect costs being due to the more visible technology products. Organizational considerations, processes/practices, and indirect costs are traditionally derived ("wrapped") only by relationship to tangible product characteristics. This traditional approach works well as long as it is understood that no significant changes, and by relation no significant improvements, are being pursued in the area of either the government acquisition or industry?s indirect costs. In this sense then, most launch systems cost models ignore most costs. The alternative was implemented in this LCC study, whereby the approach considered technology and process/practices in balance, with as much detail for one as the other. This RBS LCC study has avoided point-designs, for now, instead emphasizing exploring the trade-space of potential technology advances joined with potential process/practice advances. Given the range of decisions, and all their combinations, it was necessary to create a model of the original model
New Approaches in Reusable Booster System Life Cycle Cost Modeling
Zapata, Edgar
2013-01-01
This paper presents the results of a 2012 life cycle cost (LCC) study of hybrid Reusable Booster Systems (RBS) conducted by NASA Kennedy Space Center (KSC) and the Air Force Research Laboratory (AFRL). The work included the creation of a new cost estimating model and an LCC analysis, building on past work where applicable, but emphasizing the integration of new approaches in life cycle cost estimation. Specifically, the inclusion of industry processes/practices and indirect costs were a new and significant part of the analysis. The focus of LCC estimation has traditionally been from the perspective of technology, design characteristics, and related factors such as reliability. Technology has informed the cost related support to decision makers interested in risk and budget insight. This traditional emphasis on technology occurs even though it is well established that complex aerospace systems costs are mostly about indirect costs, with likely only partial influence in these indirect costs being due to the more visible technology products. Organizational considerations, processes/practices, and indirect costs are traditionally derived ("wrapped") only by relationship to tangible product characteristics. This traditional approach works well as long as it is understood that no significant changes, and by relation no significant improvements, are being pursued in the area of either the government acquisition or industry?s indirect costs. In this sense then, most launch systems cost models ignore most costs. The alternative was implemented in this LCC study, whereby the approach considered technology and process/practices in balance, with as much detail for one as the other. This RBS LCC study has avoided point-designs, for now, instead emphasizing exploring the trade-space of potential technology advances joined with potential process/practice advances. Given the range of decisions, and all their combinations, it was necessary to create a model of the original model
Fractal approach to computer-analytical modelling of tree crown
International Nuclear Information System (INIS)
Berezovskaya, F.S.; Karev, G.P.; Kisliuk, O.F.; Khlebopros, R.G.; Tcelniker, Yu.L.
1993-09-01
In this paper we discuss three approaches to the modeling of a tree crown development. These approaches are experimental (i.e. regressive), theoretical (i.e. analytical) and simulation (i.e. computer) modeling. The common assumption of these is that a tree can be regarded as one of the fractal objects which is the collection of semi-similar objects and combines the properties of two- and three-dimensional bodies. We show that a fractal measure of crown can be used as the link between the mathematical models of crown growth and light propagation through canopy. The computer approach gives the possibility to visualize a crown development and to calibrate the model on experimental data. In the paper different stages of the above-mentioned approaches are described. The experimental data for spruce, the description of computer system for modeling and the variant of computer model are presented. (author). 9 refs, 4 figs
Phytoplankton as Particles - A New Approach to Modeling Algal Blooms
2013-07-01
ER D C/ EL T R -1 3 -1 3 Civil Works Basic Research Program Phytoplankton as Particles – A New Approach to Modeling Algal Blooms E nv... Phytoplankton as Particles – A New Approach to Modeling Algal Blooms Carl F. Cerco and Mark R. Noel Environmental Laboratory U.S. Army Engineer Research... phytoplankton blooms can be modeled by treating phytoplankton as discrete particles capable of self- induced transport via buoyancy regulation or other
Contribution of a companion modelling approach
African Journals Online (AJOL)
2009-09-16
Sep 16, 2009 ... This paper describes the role of participatory modelling and simulation as a way to provide a meaningful framework to enable actors to understand the interdependencies in peri-urban catchment management. A role-playing game, connecting the quantitative and qualitative dynamics of the resources with ...
Numerical modelling approach for mine backfill
Indian Academy of Sciences (India)
Muhammad Zaka Emad
2017-07-24
Jul 24, 2017 ... Abstract. Numerical modelling is broadly used for assessing complex scenarios in underground mines, including mining sequence and blast-induced vibrations from production blasting. Sublevel stoping mining methods with delayed backfill are extensively used to exploit steeply dipping ore bodies by ...
Energy and development : A modelling approach
van Ruijven, B.J.|info:eu-repo/dai/nl/304834521
2008-01-01
Rapid economic growth of developing countries like India and China implies that these countries become important actors in the global energy system. Examples of this impact are the present day oil shortages and rapidly increasing emissions of greenhouse gases. Global energy models are used explore
Numerical modelling approach for mine backfill
Indian Academy of Sciences (India)
Muhammad Zaka Emad
2017-07-24
Jul 24, 2017 ... pulse is applied as a stress history on the CRF stope. Blast wave data obtained from the on-site monitoring are very complex. It requires processing before interpreting and using it for numerical models. Generally, mining compa- nies hire geophysics experts for interpretation of such data. The blast wave ...
A new approach to model mixed hydrates
Czech Academy of Sciences Publication Activity Database
Hielscher, S.; Vinš, Václav; Jäger, A.; Hrubý, Jan; Breitkopf, C.; Span, R.
2018-01-01
Roč. 459, March (2018), s. 170-185 ISSN 0378-3812 R&D Projects: GA ČR(CZ) GA17-08218S Institutional support: RVO:61388998 Keywords : gas hydrate * mixture * modeling Subject RIV: BJ - Thermodynamics Impact factor: 2.473, year: 2016 https://www. science direct.com/ science /article/pii/S0378381217304983
International Nuclear Information System (INIS)
Fazio, C; Guastella, I; Tarantino, G
2007-01-01
In this paper, we describe a pedagogical approach to elastic body movement based on measurements of the contact times between a metallic rod and small bodies colliding with it and on modelling of the experimental results by using a microcomputer-based laboratory and simulation tools. The experiments and modelling activities have been built in the context of the laboratory of mechanical wave propagation of the two-year graduate teacher education programme of Palermo's University. Some considerations about observed modifications in trainee teachers' attitudes in utilizing experiments and modelling are discussed
Convergence models for cylindrical caverns and the resulting ground subsidence
Energy Technology Data Exchange (ETDEWEB)
Haupt, W.; Sroka, A.; Schober, F.
1983-02-01
The authors studied the effects of different convergence characteristics on surface soil response for the case of narrow, cylindrical caverns. Maximum ground subsidence - a parameter of major importance in this type of cavern - was calculated for different convergence models. The models were established without considering the laws of rock mechanics and rheology. As a result, two limiting convergence models were obtained that describe an interval of expectation into which all other models fit. This means that ground movements over cylindrical caverns can be calculated ''on the safe side'', correlating the trough resulting on the surface with the convergence characterisitcs of the cavern. Among other applications, the method thus permits monitoring of caverns.
Meteorological Uncertainty of atmospheric Dispersion model results (MUD)
DEFF Research Database (Denmark)
Havskov Sørensen, Jens; Amstrup, Bjarne; Feddersen, Henrik
. However, recent developments in numerical weather prediction (NWP) include probabilistic forecasting techniques, which can be utilised also for atmospheric dispersion models. The ensemble statistical methods developed and applied to NWP models aim at describing the inherent uncertainties......The MUD project addresses assessment of uncertainties of atmospheric dispersion model predictions, as well as optimum presentation to decision makers. Previously, it has not been possible to estimate such uncertainties quantitatively, but merely to calculate the 'most likely' dispersion scenario...... of the meteorological model results. These uncertainties stem from e.g. limits in meteorological obser-vations used to initialise meteorological forecast series. By perturbing the initial state of an NWP model run in agreement with the available observa-tional data, an ensemble of meteorological forecasts is produced...
Meteorological Uncertainty of atmospheric Dispersion model results (MUD)
DEFF Research Database (Denmark)
Havskov Sørensen, Jens; Amstrup, Bjarne; Feddersen, Henrik
’ dispersion scenario. However, recent developments in numerical weather prediction (NWP) include probabilistic forecasting techniques, which can be utilised also for long-range atmospheric dispersion models. The ensemble statistical methods developed and applied to NWP models aim at describing the inherent......The MUD project addresses assessment of uncertainties of atmospheric dispersion model predictions, as well as possibilities for optimum presentation to decision makers. Previously, it has not been possible to estimate such uncertainties quantitatively, but merely to calculate the ‘most likely...... uncertainties of the meteorological model results. These uncertainties stem from e.g. limits in meteorological observations used to initialise meteorological forecast series. By perturbing e.g. the initial state of an NWP model run in agreement with the available observational data, an ensemble...
Modelling thermal plume impacts - Kalpakkam approach
International Nuclear Information System (INIS)
Rao, T.S.; Anup Kumar, B.; Narasimhan, S.V.
2002-01-01
A good understanding of temperature patterns in the receiving waters is essential to know the heat dissipation from thermal plumes originating from coastal power plants. The seasonal temperature profiles of the Kalpakkam coast near Madras Atomic Power Station (MAPS) thermal out fall site are determined and analysed. It is observed that the seasonal current reversal in the near shore zone is one of the major mechanisms for the transport of effluents away from the point of mixing. To further refine our understanding of the mixing and dilution processes, it is necessary to numerically simulate the coastal ocean processes by parameterising the key factors concerned. In this paper, we outline the experimental approach to achieve this objective. (author)
The 2013 European Seismic Hazard Model: key components and results
Jochen Woessner; Danciu Laurentiu; Domenico Giardini; Helen Crowley; Fabrice Cotton; G. Grünthal; Gianluca Valensise; Ronald Arvidsson; Roberto Basili; Mine Betül Demircioglu; Stefan Hiemer; Carlo Meletti; Roger W. Musson; Andrea N. Rovida; Karin Sesetyan
2015-01-01
The 2013 European Seismic Hazard Model (ESHM13) results from a community-based probabilistic seismic hazard assessment supported by the EU-FP7 project “Seismic Hazard Harmonization in Europe” (SHARE, 2009–2013). The ESHM13 is a consistent seismic hazard model for Europe and Turkey which overcomes the limitation of national borders and includes a through quantification of the uncertainties. It is the first completed regional effort contributing to the “Global Earthquake Model” initiative. It m...
Worldline approach to the Grosse-Wulkenhaar model
Viñas, Sebastián Franchino; Pisani, Pablo
2014-11-01
We apply the worldline formalism to the Grosse-Wulkenhaar model and obtain an expression for the one-loop effective action which provides an efficient way for computing Schwinger functions in this theory. Using this expression we obtain the quantum corrections to the effective background and the β-functions, which are known to vanish at the self-dual point. The case of degenerate noncommutativity is also considered. Our main result can be straightforwardly applied to any polynomial self-interaction of the scalar field and we consider that the worldline approach could be useful for studying effective actions of noncommutative gauge fields as well as in other non-local models or in higher-derivative field theories.
Comparison of different approaches of modelling in a masonry building
Saba, M.; Meloni, D.
2017-12-01
The present work has the objective to model a simple masonry building, through two different modelling methods in order to assess their validity in terms of evaluation of static stresses. Have been chosen two of the most commercial software used to address this kind of problem, which are of S.T.A. Data S.r.l. and Sismicad12 of Concrete S.r.l. While the 3Muri software adopts the Frame by Macro Elements Method (FME), which should be more schematic and more efficient, Sismicad12 software uses the Finite Element Method (FEM), which guarantees accurate results, with greater computational burden. Remarkably differences of the static stresses, for such a simple structure between the two approaches have been found, and an interesting comparison and analysis of the reasons is proposed.
The Use of Modeling Approach for Teaching Exponential Functions
Nunes, L. F.; Prates, D. B.; da Silva, J. M.
2017-12-01
This work presents a discussion related to the teaching and learning of mathematical contents related to the study of exponential functions in a freshman students group enrolled in the first semester of the Science and Technology Bachelor’s (STB of the Federal University of Jequitinhonha and Mucuri Valleys (UFVJM). As a contextualization tool strongly mentioned in the literature, the modelling approach was used as an educational teaching tool to produce contextualization in the teaching-learning process of exponential functions to these students. In this sense, were used some simple models elaborated with the GeoGebra software and, to have a qualitative evaluation of the investigation and the results, was used Didactic Engineering as a methodology research. As a consequence of this detailed research, some interesting details about the teaching and learning process were observed, discussed and described.
Global GPS Ionospheric Modelling Using Spherical Harmonic Expansion Approach
Directory of Open Access Journals (Sweden)
Byung-Kyu Choi
2010-12-01
Full Text Available In this study, we developed a global ionosphere model based on measurements from a worldwide network of global positioning system (GPS. The total number of the international GPS reference stations for development of ionospheric model is about 100 and the spherical harmonic expansion approach as a mathematical method was used. In order to produce the ionospheric total electron content (TEC based on grid form, we defined spatial resolution of 2.0 degree and 5.0 degree in latitude and longitude, respectively. Two-dimensional TEC maps were constructed within the interval of one hour, and have a high temporal resolution compared to global ionosphere maps which are produced by several analysis centers. As a result, we could detect the sudden increase of TEC by processing GPS observables on 29 October, 2003 when the massive solar flare took place.
Static models, recursive estimators and the zero-variance approach
Rubino, Gerardo
2016-01-07
When evaluating dependability aspects of complex systems, most models belong to the static world, where time is not an explicit variable. These models suffer from the same problems than dynamic ones (stochastic processes), such as the frequent combinatorial explosion of the state spaces. In the Monte Carlo domain, on of the most significant difficulties is the rare event situation. In this talk, we describe this context and a recent technique that appears to be at the top performance level in the area, where we combined ideas that lead to very fast estimation procedures with another approach called zero-variance approximation. Both ideas produced a very efficient method that has the right theoretical property concerning robustness, the Bounded Relative Error one. Some examples illustrate the results.
Simplistic approach for 2D grown-in microdefect modeling
Energy Technology Data Exchange (ETDEWEB)
Prostomolotov, Anatoly; Verezub, Nataliya [Institute for Problems in Mechanics, Russian Academy of Sciences, Moscow (Russian Federation)
2009-08-15
In the present paper the analysis of cooling conditions influence on microdefect formation in Si single crystal was carried out on the basis of an analytical formulation for crystal temperature field jointly with developed two-dimensional (2D) models of microdefect formation. The new mathematical model is applied for calculations of vacancy microdefect formation, in which the 2D vacancy migration process is taken into account and the approached calculation algorithm is offered, which is not requiring the data storage for whole defect growth pre-history. The calculated results are discussed for conditions of Cz silicon single crystal growing. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Modelling approach for photochemical pollution studies
International Nuclear Information System (INIS)
Silibello, C.; Catenacci, G.; Calori, G.; Crapanzano, G.; Pirovano, G.
1996-01-01
The comprehension of the relationships between primary pollutants emissions and secondary pollutants concentration and deposition is necessary to design policies and strategies for the maintenance of a healthy environment. The use of mathematical models is a powerful tool to assess the effect of the emissions and of physical and chemical transformations of pollutants on air quality. A photochemical model, Calgrid, developed by CARB (California Air Resources Board), has been used to test the effect of different meteorological and air quality, scenarios on the ozone concentration levels. This way we can evaluate the influence of these conditions to determine the most important chemical species and reactions in atmosphere. The ozone levels are strongly related to the reactive hydrocarbons concentrations and to the solar radiation flux
A Modeling Approach for Plastic-Metal Laser Direct Joining
Lutey, Adrian H. A.; Fortunato, Alessandro; Ascari, Alessandro; Romoli, Luca
2017-09-01
Laser processing has been identified as a feasible approach to direct joining of metal and plastic components without the need for adhesives or mechanical fasteners. The present work sees development of a modeling approach for conduction and transmission laser direct joining of these materials based on multi-layer optical propagation theory and numerical heat flow simulation. The scope of this methodology is to predict process outcomes based on the calculated joint interface and upper surface temperatures. Three representative cases are considered for model verification, including conduction joining of PBT and aluminum alloy, transmission joining of optically transparent PET and stainless steel, and transmission joining of semi-transparent PA 66 and stainless steel. Conduction direct laser joining experiments are performed on black PBT and 6082 anticorodal aluminum alloy, achieving shear loads of over 2000 N with specimens of 2 mm thickness and 25 mm width. Comparison with simulation results shows that consistently high strength is achieved where the peak interface temperature is above the plastic degradation temperature. Comparison of transmission joining simulations and published experimental results confirms these findings and highlights the influence of plastic layer optical absorption on process feasibility.
Right approach to 3D modeling using CAD tools
Baddam, Mounica Reddy
The thesis provides a step-by-step methodology to enable an instructor dealing with CAD tools to optimally guide his/her students through an understandable 3D modeling approach which will not only enhance their knowledge about the tool's usage but also enable them to achieve their desired result in comparatively lesser time. In the known practical field, there is particularly very little information available to apply CAD skills to formal beginners' training sessions. Additionally, advent of new software in 3D domain cumulates updating into a more difficult task. Keeping up to the industry's advanced requirements emphasizes the importance of more skilled hands in the field of CAD development, rather than just prioritizing manufacturing in terms of complex software features. The thesis analyses different 3D modeling approaches specified to the varieties of CAD tools currently available in the market. Utilizing performance-time databases, learning curves have been generated to measure their performance time, feature count etc. Based on the results, improvement parameters have also been provided for (Asperl, 2005).
Colour texture segmentation using modelling approach
Czech Academy of Sciences Publication Activity Database
Haindl, Michal; Mikeš, Stanislav
2005-01-01
Roč. 3687, č. - (2005), s. 484-491 ISSN 0302-9743. [International Conference on Advances in Pattern Recognition /3./. Bath, 22.08.2005-25.08.2005] R&D Projects: GA MŠk 1M0572; GA AV ČR 1ET400750407; GA AV ČR IAA2075302 Institutional research plan: CEZ:AV0Z10750506 Keywords : colour texture segmentation * image models * segmentation benchmark Subject RIV: BD - Theory of Information
Tumour resistance to cisplatin: a modelling approach
International Nuclear Information System (INIS)
Marcu, L; Bezak, E; Olver, I; Doorn, T van
2005-01-01
Although chemotherapy has revolutionized the treatment of haematological tumours, in many common solid tumours the success has been limited. Some of the reasons for the limitations are: the timing of drug delivery, resistance to the drug, repopulation between cycles of chemotherapy and the lack of complete understanding of the pharmacokinetics and pharmacodynamics of a specific agent. Cisplatin is among the most effective cytotoxic agents used in head and neck cancer treatments. When modelling cisplatin as a single agent, the properties of cisplatin only have to be taken into account, reducing the number of assumptions that are considered in the generalized chemotherapy models. The aim of the present paper is to model the biological effect of cisplatin and to simulate the consequence of cisplatin resistance on tumour control. The 'treated' tumour is a squamous cell carcinoma of the head and neck, previously grown by computer-based Monte Carlo techniques. The model maintained the biological constitution of a tumour through the generation of stem cells, proliferating cells and non-proliferating cells. Cell kinetic parameters (mean cell cycle time, cell loss factor, thymidine labelling index) were also consistent with the literature. A sensitivity study on the contribution of various mechanisms leading to drug resistance is undertaken. To quantify the extent of drug resistance, the cisplatin resistance factor (CRF) is defined as the ratio between the number of surviving cells of the resistant population and the number of surviving cells of the sensitive population, determined after the same treatment time. It is shown that there is a supra-linear dependence of CRF on the percentage of cisplatin-DNA adducts formed, and a sigmoid-like dependence between CRF and the percentage of cells killed in resistant tumours. Drug resistance is shown to be a cumulative process which eventually can overcome tumour regression leading to treatment failure
Hydroclimatology of the Nile: results from a regional climate model
Directory of Open Access Journals (Sweden)
Y. A. Mohamed
2005-01-01
Full Text Available This paper presents the result of the regional coupled climatic and hydrologic model of the Nile Basin. For the first time the interaction between the climatic processes and the hydrological processes on the land surface have been fully coupled. The hydrological model is driven by the rainfall and the energy available for evaporation generated in the climate model, and the runoff generated in the catchment is again routed over the wetlands of the Nile to supply moisture for atmospheric feedback. The results obtained are quite satisfactory given the extremely low runoff coefficients in the catchment. The paper presents the validation results over the sub-basins: Blue Nile, White Nile, Atbara river, the Sudd swamps, and the Main Nile for the period 1995 to 2000. Observational datasets were used to evaluate the model results including radiation, precipitation, runoff and evaporation data. The evaporation data were derived from satellite images over a major part of the Upper Nile. Limitations in both the observational data and the model are discussed. It is concluded that the model provides a sound representation of the regional water cycle over the Nile. The sources of atmospheric moisture to the basin, and location of convergence/divergence fields could be accurately illustrated. The model is used to describe the regional water cycle in the Nile basin in terms of atmospheric fluxes, land surface fluxes and land surface-climate feedbacks. The monthly moisture recycling ratio (i.e. locally generated/total precipitation over the Nile varies between 8 and 14%, with an annual mean of 11%, which implies that 89% of the Nile water resources originates from outside the basin physical boundaries. The monthly precipitation efficiency varies between 12 and 53%, and the annual mean is 28%. The mean annual result of the Nile regional water cycle is compared to that of the Amazon and the Mississippi basins.
Results of a model for premixed combustion oscillations
Energy Technology Data Exchange (ETDEWEB)
Janus, M.C.; Richards, G.A.
1996-09-01
Combustion oscillations are receiving renewed research interest due to increasing use of lean premix (LPM) combustion to gas turbines. A simple, nonlinear model for premixed combustion is described in this paper. The model was developed to help explain specific experimental observations and to provide guidance for development of active control schemes based on nonlinear concepts. The model can be used to quickly examine instability trends associated with changes in equivalence ratio, mass flow rate, geometry, ambient conditions, etc. The model represents the relevant processes occurring in a fuel nozzle and combustor which are analogous to current LPM turbine combustors. Conservation equations for the fuel nozzle and combustor are developed from simple control volume analysis, providing a set of ordinary differential equations that can be solved on a personal computer. Combustion is modeled as a stirred reactor, with a bimolecular reaction rate between fuel and air. A variety of numerical results and comparisons to experimental data are presented to demonstrate the utility of the model. Model results are used to understand the fundamental mechanisms which drive combustion oscillations, effects of inlet air temperature and nozzle geometry on instability, and effectiveness of open loop control schemes.
Summary of FY15 results of benchmark modeling activities
Energy Technology Data Exchange (ETDEWEB)
Arguello, J. Guadalupe [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2015-08-01
Sandia is participating in the third phase of an is a contributing partner to a U.S.-German "Joint Project" entitled "Comparison of current constitutive models and simulation procedures on the basis of model calculations of the thermo-mechanical behavior and healing of rock salt." The first goal of the project is to check the ability of numerical modeling tools to correctly describe the relevant deformation phenomena in rock salt under various influences. Achieving this goal will lead to increased confidence in the results of numerical simulations related to the secure storage of radioactive wastes in rock salt, thereby enhancing the acceptance of the results. These results may ultimately be used to make various assertions regarding both the stability analysis of an underground repository in salt, during the operating phase, and the long-term integrity of the geological barrier against the release of harmful substances into the biosphere, in the post-operating phase.
A Modeling Approach for Earthquake-Ionosphere Coupling
Meng, X.; Komjathy, A.; Verkhoglyadova, O. P.; Savastano, G.; Mannucci, A. J.
2017-12-01
We present a newly developed modeling approach for the earthquake-ionosphere coupling process, which extends the capability of Wave Perturbation - Global Ionosphere-Thermosphere Model (WP-GITM) developed originally for tsunami-ionosphere coupling. The new WP-GITM represents an earthquake as a point source at its epicenter, and takes the ground vertical velocity data from seismic measurements as input. The model then solves the neutral density, velocity, and temperature perturbations generated by spherical acoustic-gravity waves and the resulting perturbations in ions and electrons. We apply the model to simulate the near-field ionospheric disturbances during two earthquake events with different local times including the 2011 Tohoku-Oki (local afternoon) and the 2015 Illapel events (local evening). To validate the results, we retrieve receiver-to-satellite total electron content (TEC) perturbations from the simulations and compare them to the corresponding slant TEC perturbations from Global Positioning System (GPS) TEC observations. We find good agreement on magnitudes and arrival times between the simulations and observations and discuss directions of future research.
A parsimonious approach to modeling animal movement data.
Directory of Open Access Journals (Sweden)
Yann Tremblay
Full Text Available Animal tracking is a growing field in ecology and previous work has shown that simple speed filtering of tracking data is not sufficient and that improvement of tracking location estimates are possible. To date, this has required methods that are complicated and often time-consuming (state-space models, resulting in limited application of this technique and the potential for analysis errors due to poor understanding of the fundamental framework behind the approach. We describe and test an alternative and intuitive approach consisting of bootstrapping random walks biased by forward particles. The model uses recorded data accuracy estimates, and can assimilate other sources of data such as sea-surface temperature, bathymetry and/or physical boundaries. We tested our model using ARGOS and geolocation tracks of elephant seals that also carried GPS tags in addition to PTTs, enabling true validation. Among pinnipeds, elephant seals are extreme divers that spend little time at the surface, which considerably impact the quality of both ARGOS and light-based geolocation tracks. Despite such low overall quality tracks, our model provided location estimates within 4.0, 5.5 and 12.0 km of true location 50% of the time, and within 9, 10.5 and 20.0 km 90% of the time, for above, equal or below average elephant seal ARGOS track qualities, respectively. With geolocation data, 50% of errors were less than 104.8 km (<0.94 degrees, and 90% were less than 199.8 km (<1.80 degrees. Larger errors were due to lack of sea-surface temperature gradients. In addition we show that our model is flexible enough to solve the obstacle avoidance problem by assimilating high resolution coastline data. This reduced the number of invalid on-land location by almost an order of magnitude. The method is intuitive, flexible and efficient, promising extensive utilization in future research.
Ensembles modeling approach to study Climate Change impacts on Wheat
Ahmed, Mukhtar; Claudio, Stöckle O.; Nelson, Roger; Higgins, Stewart
2017-04-01
Simulations of crop yield under climate variability are subject to uncertainties, and quantification of such uncertainties is essential for effective use of projected results in adaptation and mitigation strategies. In this study we evaluated the uncertainties related to crop-climate models using five crop growth simulation models (CropSyst, APSIM, DSSAT, STICS and EPIC) and 14 general circulation models (GCMs) for 2 representative concentration pathways (RCP) of atmospheric CO2 (4.5 and 8.5 W m-2) in the Pacific Northwest (PNW), USA. The aim was to assess how different process-based crop models could be used accurately for estimation of winter wheat growth, development and yield. Firstly, all models were calibrated for high rainfall, medium rainfall, low rainfall and irrigated sites in the PNW using 1979-2010 as the baseline period. Response variables were related to farm management and soil properties, and included crop phenology, leaf area index (LAI), biomass and grain yield of winter wheat. All five models were run from 2000 to 2100 using the 14 GCMs and 2 RCPs to evaluate the effect of future climate (rainfall, temperature and CO2) on winter wheat phenology, LAI, biomass, grain yield and harvest index. Simulated time to flowering and maturity was reduced in all models except EPIC with some level of uncertainty. All models generally predicted an increase in biomass and grain yield under elevated CO2 but this effect was more prominent under rainfed conditions than irrigation. However, there was uncertainty in the simulation of crop phenology, biomass and grain yield under 14 GCMs during three prediction periods (2030, 2050 and 2070). We concluded that to improve accuracy and consistency in simulating wheat growth dynamics and yield under a changing climate, a multimodel ensemble approach should be used.
Directory of Open Access Journals (Sweden)
A.A. Kobozeva
2016-09-01
Full Text Available The problem of detection of the digital image falsification results performed by cloning is considered – one of the most often used program tools implemented in all modern graphic editors. Aim: The aim of the work is further development of approach to the solution of a cloning detection problem having the cloned image saved in a lossy format, offered by authors earlier. Materials and Methods: Further development of a new approach to the solution of a problem of cloning results detection in the digital image is presented. Approach is based on the accounting of small changes of cylindrical body volume with the generatrix, that is parallel to the OZ axis, bounded above by the interpolating function plot for a matrix of brightness of the analyzed image, and bounded below by the XOY plane, during the compression process. Results: Adaptation of the offered approach to conditions of the cloned image compression with the arbitrary factor of compression quality is carried out (compression ratio. The approach solvency in the conditions of the cloned image compression according to the algorithms different from the JPEG standard is shown: JPEG2000, compression with use of low-rank approximations of the image matrix (matrix blocks. The results of computational experiment are given. It is shown that the developed approach can be used to detect the results of cloning in digital video in the conditions of lossy compression after cloning process.
Smeared crack modelling approach for corrosion-induced concrete damage
DEFF Research Database (Denmark)
Thybo, Anna Emilie Anusha; Michel, Alexander; Stang, Henrik
2017-01-01
In this paper a smeared crack modelling approach is used to simulate corrosion-induced damage in reinforced concrete. The presented modelling approach utilizes a thermal analogy to mimic the expansive nature of solid corrosion products, while taking into account the penetration of corrosion...... products into the surrounding concrete, non-uniform precipitation of corrosion products, and creep. To demonstrate the applicability of the presented modelling approach, numerical predictions in terms of corrosion-induced deformations as well as formation and propagation of micro- and macrocracks were...
Applied Regression Modeling A Business Approach
Pardoe, Iain
2012-01-01
An applied and concise treatment of statistical regression techniques for business students and professionals who have little or no background in calculusRegression analysis is an invaluable statistical methodology in business settings and is vital to model the relationship between a response variable and one or more predictor variables, as well as the prediction of a response value given values of the predictors. In view of the inherent uncertainty of business processes, such as the volatility of consumer spending and the presence of market uncertainty, business professionals use regression a
Jackiw-Pi model: A superfield approach
Gupta, Saurabh
2014-12-01
We derive the off-shell nilpotent and absolutely anticommuting Becchi-Rouet-Stora-Tyutin (BRST) as well as anti-BRST transformations s ( a) b corresponding to the Yang-Mills gauge transformations of 3D Jackiw-Pi model by exploiting the "augmented" super-field formalism. We also show that the Curci-Ferrari restriction, which is a hallmark of any non-Abelian 1-form gauge theories, emerges naturally within this formalism and plays an instrumental role in providing the proof of absolute anticommutativity of s ( a) b .
A modular approach to numerical human body modeling
Forbes, P.A.; Griotto, G.; Rooij, L. van
2007-01-01
The choice of a human body model for a simulated automotive impact scenario must take into account both accurate model response and computational efficiency as key factors. This study presents a "modular numerical human body modeling" approach which allows the creation of a customized human body
Mathematical Modeling in Mathematics Education: Basic Concepts and Approaches
Erbas, Ayhan Kürsat; Kertil, Mahmut; Çetinkaya, Bülent; Çakiroglu, Erdinç; Alacaci, Cengiz; Bas, Sinem
2014-01-01
Mathematical modeling and its role in mathematics education have been receiving increasing attention in Turkey, as in many other countries. The growing body of literature on this topic reveals a variety of approaches to mathematical modeling and related concepts, along with differing perspectives on the use of mathematical modeling in teaching and…
Southam-Gerow, Michael A.; Hourigan, Shannon E.; Allin, Robert B., Jr.
2009-01-01
This article describes the application of a university-community partnership model to the problem of adapting evidence-based treatment approaches in a community mental health setting. Background on partnership research is presented, with consideration of methodological and practical issues related to this kind of research. Then, a rationale for…
Implicit moral evaluations: A multinomial modeling approach.
Cameron, C Daryl; Payne, B Keith; Sinnott-Armstrong, Walter; Scheffer, Julian A; Inzlicht, Michael
2017-01-01
Implicit moral evaluations-i.e., immediate, unintentional assessments of the wrongness of actions or persons-play a central role in supporting moral behavior in everyday life. Yet little research has employed methods that rigorously measure individual differences in implicit moral evaluations. In five experiments, we develop a new sequential priming measure-the Moral Categorization Task-and a multinomial model that decomposes judgment on this task into multiple component processes. These include implicit moral evaluations of moral transgression primes (Unintentional Judgment), accurate moral judgments about target actions (Intentional Judgment), and a directional tendency to judge actions as morally wrong (Response Bias). Speeded response deadlines reduced Intentional Judgment but not Unintentional Judgment (Experiment 1). Unintentional Judgment was stronger toward moral transgression primes than non-moral negative primes (Experiments 2-4). Intentional Judgment was associated with increased error-related negativity, a neurophysiological indicator of behavioral control (Experiment 4). Finally, people who voted for an anti-gay marriage amendment had stronger Unintentional Judgment toward gay marriage primes (Experiment 5). Across Experiments 1-4, implicit moral evaluations converged with moral personality: Unintentional Judgment about wrong primes, but not negative primes, was negatively associated with psychopathic tendencies and positively associated with moral identity and guilt proneness. Theoretical and practical applications of formal modeling for moral psychology are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.
Keyring models: An approach to steerability
Miller, Carl A.; Colbeck, Roger; Shi, Yaoyun
2018-02-01
If a measurement is made on one half of a bipartite system, then, conditioned on the outcome, the other half has a new reduced state. If these reduced states defy classical explanation—that is, if shared randomness cannot produce these reduced states for all possible measurements—the bipartite state is said to be steerable. Determining which states are steerable is a challenging problem even for low dimensions. In the case of two-qubit systems, a criterion is known for T-states (that is, those with maximally mixed marginals) under projective measurements. In the current work, we introduce the concept of keyring models—a special class of local hidden state models. When the measurements made correspond to real projectors, these allow us to study steerability beyond T-states. Using keyring models, we completely solve the steering problem for real projective measurements when the state arises from mixing a pure two-qubit state with uniform noise. We also give a partial solution in the case when the uniform noise is replaced by independent depolarizing channels.
GPA: a statistical approach to prioritizing GWAS results by integrating pleiotropy and annotation.
Directory of Open Access Journals (Sweden)
Dongjun Chung
2014-11-01
Full Text Available Results from Genome-Wide Association Studies (GWAS have shown that complex diseases are often affected by many genetic variants with small or moderate effects. Identifications of these risk variants remain a very challenging problem. There is a need to develop more powerful statistical methods to leverage available information to improve upon traditional approaches that focus on a single GWAS dataset without incorporating additional data. In this paper, we propose a novel statistical approach, GPA (Genetic analysis incorporating Pleiotropy and Annotation, to increase statistical power to identify risk variants through joint analysis of multiple GWAS data sets and annotation information because: (1 accumulating evidence suggests that different complex diseases share common risk bases, i.e., pleiotropy; and (2 functionally annotated variants have been consistently demonstrated to be enriched among GWAS hits. GPA can integrate multiple GWAS datasets and functional annotations to seek association signals, and it can also perform hypothesis testing to test the presence of pleiotropy and enrichment of functional annotation. Statistical inference of the model parameters and SNP ranking is achieved through an EM algorithm that can handle genome-wide markers efficiently. When we applied GPA to jointly analyze five psychiatric disorders with annotation information, not only did GPA identify many weak signals missed by the traditional single phenotype analysis, but it also revealed relationships in the genetic architecture of these disorders. Using our hypothesis testing framework, statistically significant pleiotropic effects were detected among these psychiatric disorders, and the markers annotated in the central nervous system genes and eQTLs from the Genotype-Tissue Expression (GTEx database were significantly enriched. We also applied GPA to a bladder cancer GWAS data set with the ENCODE DNase-seq data from 125 cell lines. GPA was able to detect cell
Fusion modeling approach for novel plasma sources
International Nuclear Information System (INIS)
Melazzi, D; Manente, M; Pavarin, D; Cardinali, A
2012-01-01
The physics involved in the coupling, propagation and absorption of RF helicon waves (electronic whistler) in low temperature Helicon plasma sources is investigated by solving the 3D Maxwell-Vlasov model equations using a WKB asymptotic expansion. The reduced set of equations is formally Hamiltonian and allows for the reconstruction of the wave front of the propagating wave, monitoring along the calculation that the WKB expansion remains satisfied. This method can be fruitfully employed in a new investigation of the power deposition mechanisms involved in common Helicon low temperature plasma sources when a general confinement magnetic field configuration is allowed, unveiling new physical insight in the wave propagation and absorption phenomena and stimulating further research for the design of innovative and more efficient low temperature plasma sources. A brief overview of this methodology and its capabilities has been presented in this paper.
Carbonate rock depositional models: A microfacies approach
Energy Technology Data Exchange (ETDEWEB)
Carozzi, A.V.
1988-01-01
Carbonate rocks contain more than 50% by weight carbonate minerals such as calcite, dolomite, and siderite. Understanding how these rocks form can lead to more efficient methods of petroleum exploration. Micofacies analysis techniques can be used as a method of predicting models of sedimentation for carbonate rocks. Micofacies in carbonate rocks can be seen clearly only in thin sections under a microscope. This section analysis of carbonate rocks is a tool that can be used to understand depositional environments, diagenetic evolution of carbonate rocks, and the formation of porosity and permeability in carbonate rocks. The use of micofacies analysis techniques is applied to understanding the origin and formation of carbonate ramps, carbonate platforms, and carbonate slopes and basins. This book will be of interest to students and professionals concerned with the disciplines of sedimentary petrology, sedimentology, petroleum geology, and palentology.
Risk prediction model: Statistical and artificial neural network approach
Paiman, Nuur Azreen; Hariri, Azian; Masood, Ibrahim
2017-04-01
Prediction models are increasingly gaining popularity and had been used in numerous areas of studies to complement and fulfilled clinical reasoning and decision making nowadays. The adoption of such models assist physician's decision making, individual's behavior, and consequently improve individual outcomes and the cost-effectiveness of care. The objective of this paper is to reviewed articles related to risk prediction model in order to understand the suitable approach, development and the validation process of risk prediction model. A qualitative review of the aims, methods and significant main outcomes of the nineteen published articles that developed risk prediction models from numerous fields were done. This paper also reviewed on how researchers develop and validate the risk prediction models based on statistical and artificial neural network approach. From the review done, some methodological recommendation in developing and validating the prediction model were highlighted. According to studies that had been done, artificial neural network approached in developing the prediction model were more accurate compared to statistical approach. However currently, only limited published literature discussed on which approach is more accurate for risk prediction model development.
Marginal production in the Gulf of Mexico - II. Model results
International Nuclear Information System (INIS)
Kaiser, Mark J.; Yu, Yunke
2010-01-01
In the second part of this two-part article on marginal production in the Gulf of Mexico, we estimate the number of committed assets in water depth less than 1000 ft that are expected to be marginal over a 60-year time horizon. We compute the expected quantity and value of the production and gross revenue streams of the gulf's committed asset inventory circa. January 2007 using a probabilistic model framework. Cumulative hydrocarbon production from the producing inventory is estimated to be 1056 MMbbl oil and 13.3 Tcf gas. Marginal production from the committed asset inventory is expected to contribute 4.1% of total oil production and 5.4% of gas production. A meta-evaluation procedure is adapted to present the results of sensitivity analysis. Model results are discussed along with a description of the model framework and limitations of the analysis. (author)
Marginal production in the Gulf of Mexico - II. Model results
Energy Technology Data Exchange (ETDEWEB)
Kaiser, Mark J.; Yu, Yunke [Center for Energy Studies, Louisiana State University, Baton Rouge, LA 70803 (United States)
2010-08-15
In the second part of this two-part article on marginal production in the Gulf of Mexico, we estimate the number of committed assets in water depth less than 1000 ft that are expected to be marginal over a 60-year time horizon. We compute the expected quantity and value of the production and gross revenue streams of the gulf's committed asset inventory circa. January 2007 using a probabilistic model framework. Cumulative hydrocarbon production from the producing inventory is estimated to be 1056 MMbbl oil and 13.3 Tcf gas. Marginal production from the committed asset inventory is expected to contribute 4.1% of total oil production and 5.4% of gas production. A meta-evaluation procedure is adapted to present the results of sensitivity analysis. Model results are discussed along with a description of the model framework and limitations of the analysis. (author)
Exploring regional economic convergence in Romania. A spatial modeling approach
Directory of Open Access Journals (Sweden)
Zizi GOSCHIN
2017-12-01
Full Text Available This paper explores spatial economic convergence in Romania, from the perspective of real GDP/capita, and examines how the shock of the recent economic crisis has affected the convergence process. Given the presence of spatial autocorrelation in the values of GDP per capita, we address the question of convergence in terms of both classic and spatial regression models, thus filling a gap in the Romanian literature on this topic. The empirical results seem to provide support for both absolute and relative beta divergence in GDP/capita, as well as sigma divergence among Romanian counties on the long run. This is the consequence of the two-speed regional development, with the capital region and some large cities thriving by attracting human capital and FDIs, while the lagging regions are systematically left behind. Failing to validate the neoclassical approach on convergence, our results rather support the new divergence theory based on polarization and centre-periphery inequality.
A dual model approach to ground water recovery trench design
International Nuclear Information System (INIS)
Clodfelter, C.L.; Crouch, M.S.
1992-01-01
The design of trenches for contaminated ground water recovery must consider several variables. This paper presents a dual-model approach for effectively recovering contaminated ground water migrating toward a trench by advection. The approach involves an analytical model to determine the vertical influence of the trench and a numerical flow model to determine the capture zone within the trench and the surrounding aquifer. The analytical model is utilized by varying trench dimensions and head values to design a trench which meets the remediation criteria. The numerical flow model is utilized to select the type of backfill and location of sumps within the trench. The dual-model approach can be used to design a recovery trench which effectively captures advective migration of contaminants in the vertical and horizontal planes
Lamont, A.E.; Vermunt, J.K.; Van Horn, M.L.
2016-01-01
Regression mixture models are increasingly used as an exploratory approach to identify heterogeneity in the effects of a predictor on an outcome. In this simulation study, we tested the effects of violating an implicit assumption often made in these models; that is, independent variables in the
Simple queueing approach to segregation dynamics in Schelling model
Sobkowicz, Pawel
2007-01-01
A simple queueing approach for segregation of agents in modified one dimensional Schelling segregation model is presented. The goal is to arrive at simple formula for the number of unhappy agents remaining after the segregation.
A systemic approach for modeling soil functions
Vogel, Hans-Jörg; Bartke, Stephan; Daedlow, Katrin; Helming, Katharina; Kögel-Knabner, Ingrid; Lang, Birgit; Rabot, Eva; Russell, David; Stößel, Bastian; Weller, Ulrich; Wiesmeier, Martin; Wollschläger, Ute
2018-03-01
The central importance of soil for the functioning of terrestrial systems is increasingly recognized. Critically relevant for water quality, climate control, nutrient cycling and biodiversity, soil provides more functions than just the basis for agricultural production. Nowadays, soil is increasingly under pressure as a limited resource for the production of food, energy and raw materials. This has led to an increasing demand for concepts assessing soil functions so that they can be adequately considered in decision-making aimed at sustainable soil management. The various soil science disciplines have progressively developed highly sophisticated methods to explore the multitude of physical, chemical and biological processes in soil. It is not obvious, however, how the steadily improving insight into soil processes may contribute to the evaluation of soil functions. Here, we present to a new systemic modeling framework that allows for a consistent coupling between reductionist yet observable indicators for soil functions with detailed process understanding. It is based on the mechanistic relationships between soil functional attributes, each explained by a network of interacting processes as derived from scientific evidence. The non-linear character of these interactions produces stability and resilience of soil with respect to functional characteristics. We anticipate that this new conceptional framework will integrate the various soil science disciplines and help identify important future research questions at the interface between disciplines. It allows the overwhelming complexity of soil systems to be adequately coped with and paves the way for steadily improving our capability to assess soil functions based on scientific understanding.
Thin inclusion approach for modelling of heterogeneous conducting materials
Lavrov, Nikolay; Smirnova, Alevtina; Gorgun, Haluk; Sammes, Nigel
Experimental data show that heterogeneous nanostructure of solid oxide and polymer electrolyte fuel cells could be approximated as an infinite set of fiber-like or penny-shaped inclusions in a continuous medium. Inclusions can be arranged in a cluster mode and regular or random order. In the newly proposed theoretical model of nanostructured material, the most attention is paid to the small aspect ratio of structural elements as well as to some model problems of electrostatics. The proposed integral equation for electric potential caused by the charge distributed over the single circular or elliptic cylindrical conductor of finite length, as a single unit of a nanostructured material, has been asymptotically simplified for the small aspect ratio and solved numerically. The result demonstrates that surface density changes slightly in the middle part of the thin domain and has boundary layers localized near the edges. It is anticipated, that contribution of boundary layer solution to the surface density is significant and cannot be governed by classic equation for smooth linear charge. The role of the cross-section shape is also investigated. Proposed approach is sufficiently simple, robust and allows extension to either regular or irregular system of various inclusions. This approach can be used for the development of the system of conducting inclusions, which are commonly present in nanostructured materials used for solid oxide and polymer electrolyte fuel cell (PEMFC) materials.
Metal Mixture Modeling Evaluation project: 2. Comparison of four modeling approaches
Farley, Kevin J.; Meyer, Joe; Balistrieri, Laurie S.; DeSchamphelaere, Karl; Iwasaki, Yuichi; Janssen, Colin; Kamo, Masashi; Lofts, Steve; Mebane, Christopher A.; Naito, Wataru; Ryan, Adam C.; Santore, Robert C.; Tipping, Edward
2015-01-01
As part of the Metal Mixture Modeling Evaluation (MMME) project, models were developed by the National Institute of Advanced Industrial Science and Technology (Japan), the U.S. Geological Survey (USA), HDR⎪HydroQual, Inc. (USA), and the Centre for Ecology and Hydrology (UK) to address the effects of metal mixtures on biological responses of aquatic organisms. A comparison of the 4 models, as they were presented at the MMME Workshop in Brussels, Belgium (May 2012), is provided herein. Overall, the models were found to be similar in structure (free ion activities computed by WHAM; specific or non-specific binding of metals/cations in or on the organism; specification of metal potency factors and/or toxicity response functions to relate metal accumulation to biological response). Major differences in modeling approaches are attributed to various modeling assumptions (e.g., single versus multiple types of binding site on the organism) and specific calibration strategies that affected the selection of model parameters. The models provided a reasonable description of additive (or nearly additive) toxicity for a number of individual toxicity test results. Less-than-additive toxicity was more difficult to describe with the available models. Because of limitations in the available datasets and the strong inter-relationships among the model parameters (log KM values, potency factors, toxicity response parameters), further evaluation of specific model assumptions and calibration strategies is needed.
Approaches and results for recent shutdown risk studies in the US
International Nuclear Information System (INIS)
Hanan, N.A.; Bhattacharyya, S.K.
1995-09-01
This paper provides a description of the methods/approaches used in three contemporary Probabilistic Safety Assessments for two PWRs (Seabrook and Surry) and for one BWR (Grand Gulf ). The results for the core damage frequency for those studies and the most important contributors are discussed. A summary of the novel approaches (when compared to PSAs for power operation) introduced in these studies is provided
A Constructive Neural-Network Approach to Modeling Psychological Development
Shultz, Thomas R.
2012-01-01
This article reviews a particular computational modeling approach to the study of psychological development--that of constructive neural networks. This approach is applied to a variety of developmental domains and issues, including Piagetian tasks, shift learning, language acquisition, number comparison, habituation of visual attention, concept…
Towards Translating Graph Transformation Approaches by Model Transformations
Hermann, F.; Kastenberg, H.; Modica, T.; Karsai, G.; Taentzer, G.
2006-01-01
Recently, many researchers are working on semantics preserving model transformation. In the field of graph transformation one can think of translating graph grammars written in one approach to a behaviourally equivalent graph grammar in another approach. In this paper we translate graph grammars
An Almost Integration-free Approach to Ordered Response Models
van Praag, B.M.S.; Ferrer-i-Carbonell, A.
2006-01-01
'In this paper we propose an alternative approach to the estimation of ordered response models. We show that the Probit-method may be replaced by a simple OLS-approach, called P(robit)OLS, without any loss of efficiency. This method can be generalized to the analysis of panel data. For large-scale
Optimizing technology investments: a broad mission model approach
Shishko, R.
2003-01-01
A long-standing problem in NASA is how to allocate scarce technology development resources across advanced technologies in order to best support a large set of future potential missions. Within NASA, two orthogonal paradigms have received attention in recent years: the real-options approach and the broad mission model approach. This paper focuses on the latter.
A generalized quarter car modelling approach with frame flexibility ...
Indian Academy of Sciences (India)
... mass distribution and damping. Here we propose a generalized quarter-car modelling approach, incorporating both the frame as well as other-wheel ground contacts. Our approach is linear, uses Laplace transforms, involves vertical motions of key points of interest and has intermediate complexity with improved realism.
Modeling Results For the ITER Cryogenic Fore Pump. Final Report
Energy Technology Data Exchange (ETDEWEB)
Pfotenhauer, John M. [University of Wisconsin, Madison, WI (United States); Zhang, Dongsheng [University of Wisconsin, Madison, WI (United States)
2014-03-31
A numerical model characterizing the operation of a cryogenic fore-pump (CFP) for ITER has been developed at the University of Wisconsin – Madison during the period from March 15, 2011 through June 30, 2014. The purpose of the ITER-CFP is to separate hydrogen isotopes from helium gas, both making up the exhaust components from the ITER reactor. The model explicitly determines the amount of hydrogen that is captured by the supercritical-helium-cooled pump as a function of the inlet temperature of the supercritical helium, its flow rate, and the inlet conditions of the hydrogen gas flow. Furthermore the model computes the location and amount of hydrogen captured in the pump as a function of time. Throughout the model’s development, and as a calibration check for its results, it has been extensively compared with the measurements of a CFP prototype tested at Oak Ridge National Lab. The results of the model demonstrate that the quantity of captured hydrogen is very sensitive to the inlet temperature of the helium coolant on the outside of the cryopump. Furthermore, the model can be utilized to refine those tests, and suggests methods that could be incorporated in the testing to enhance the usefulness of the measured data.
Replacement model of city bus: A dynamic programming approach
Arifin, Dadang; Yusuf, Edhi
2017-06-01
This paper aims to develop a replacement model of city bus vehicles operated in Bandung City. This study is driven from real cases encountered by the Damri Company in the efforts to improve services to the public. The replacement model propounds two policy alternatives: First, to maintain or keep the vehicles, and second is to replace them with new ones taking into account operating costs, revenue, salvage value, and acquisition cost of a new vehicle. A deterministic dynamic programming approach is used to solve the model. The optimization process was heuristically executed using empirical data of Perum Damri. The output of the model is to determine the replacement schedule and the best policy if the vehicle has passed the economic life. Based on the results, the technical life of the bus is approximately 20 years old, while the economic life is an average of 9 (nine) years. It means that after the bus is operated for 9 (nine) years, managers should consider the policy of rejuvenation.
Realistic Matematic Approach through Numbered Head Together Learning Model
Sugihatno, A. C. M. S.; Budiyono; Slamet, I.
2017-09-01
Recently, the teaching process which is conducted based on teacher center affect the students interaction in the class. It causes students become less interest to participate. That is why teachers should be more creative in designing learning using other types of cooperative learning model. Therefore, this research is aimed to implement NHT with RMA in the teaching process. We utilize NHT since it is a variant of group discussion whose aim is giving a chance to the students to share their ideas related to the teacher’s question. By using NHT in the class, a teacher can give a better understanding about the material which is given with the help of Realistic Mathematics Approach (RMA) which known for its real problem contex. Meanwhile, the researcher assumes instead of selecting teaching model, Adversity Quotient (AQ) of student also influences students’ achievement. This research used the quasi experimental research. The samples is 60 students in junior high school, it was taken by using the stratified cluster random sampling technique. The results show NHT-RMA gives a better learning achievement of mathematics than direct teaching model and NHT-RMA teaching model with categorized as high AQ show different learning achievement from the students with categorized as moderate and low AQ.
A modelling approach to designing microstructures in thermal barrier coatings
International Nuclear Information System (INIS)
Gupta, M.; Nylen, P.; Wigren, J.
2013-01-01
Thermomechanical properties of Thermal Barrier Coatings (TBCs) are strongly influenced by coating defects, such as delaminations and pores, thus making it essential to have a fundamental understanding of microstructure-property relationships in TBCs to produce a desired coating. Object-Oriented Finite element analysis (OOF) has been shown previously as an effective tool for evaluating thermal and mechanical material behaviour, as this method is capable of incorporating the inherent material microstructure as input to the model. In this work, OOF was used to predict the thermal conductivity and effective Young's modulus of TBC topcoats. A Design of Experiments (DoE) was conducted by varying selected parameters for spraying Yttria-Stabilised Zirconia (YSZ) topcoat. The microstructure was assessed with SEM, and image analysis was used to characterize the porosity content. The relationships between microstructural features and properties predicted by modelling are discussed. The microstructural features having the most beneficial effect on properties were sprayed with a different spray gun so as to verify the results obtained from modelling. Characterisation of the coatings included microstructure evaluation, thermal conductivity and lifetime measurements. The modelling approach in combination with experiments undertaken in this study was shown to be an effective way to achieve coatings with optimised thermo-mechanical properties.
Fuel assembly bow: analytical modeling and resulting design improvements
International Nuclear Information System (INIS)
Stabel, J.; Huebsch, H.P.
1995-01-01
The bowing of fuel assemblies may result in a contact between neighbouring fuel assemblies and in connection with a vibration to a resulting wear or even perforation at the corners of the spacer grids of neighbouring assemblies. Such events allowed reinsertion of a few fuel assemblies in Germany only after spacer repair. In order to identify the most sensitive parameters causing the observed bowing of fuel assemblies a new computer model was develop which takes into a account the highly nonlinear behaviour of the interaction between fuel rods and spacers. As a result of the studies performed with this model, design improvements such as a more rigid connection between guide thimbles and spacer grids, could be defined. First experiences with this improved design show significantly better fuel behaviour. (author). 5 figs., 1 tabs
Numerical approaches to expansion process modeling
Directory of Open Access Journals (Sweden)
G. V. Alekseev
2017-01-01
Full Text Available Forage production is currently undergoing a period of intensive renovation and introduction of the most advanced technologies and equipment. More and more often such methods as barley toasting, grain extrusion, steaming and grain flattening, boiling bed explosion, infrared ray treatment of cereals and legumes, followed by flattening, and one-time or two-time granulation of the purified whole grain without humidification in matrix presses By grinding the granules. These methods require special apparatuses, machines, auxiliary equipment, created on the basis of different methods of compiled mathematical models. When roasting, simulating the heat fields arising in the working chamber, provide such conditions, the decomposition of a portion of the starch to monosaccharides, which makes the grain sweetish, but due to protein denaturation the digestibility of the protein and the availability of amino acids decrease somewhat. Grain is roasted mainly for young animals in order to teach them to eat food at an early age, stimulate the secretory activity of digestion, better development of the masticatory muscles. In addition, the high temperature is detrimental to bacterial contamination and various types of fungi, which largely avoids possible diseases of the gastrointestinal tract. This method has found wide application directly on the farms. Apply when used in feeding animals and legumes: peas, soy, lupine and lentils. These feeds are preliminarily ground, and then cooked or steamed for 1 hour for 30–40 minutes. In the feed mill. Such processing of feeds allows inactivating the anti-nutrients in them, which reduce the effectiveness of their use. After processing, legumes are used as protein supplements in an amount of 25–30% of the total nutritional value of the diet. But it is recommended to cook and steal a grain of good quality. A poor-quality grain that has been stored for a long time and damaged by pathogenic micro flora is subject to
Graphical approach to model reduction for nonlinear biochemical networks.
Holland, David O; Krainak, Nicholas C; Saucerman, Jeffrey J
2011-01-01
Model reduction is a central challenge to the development and analysis of multiscale physiology models. Advances in model reduction are needed not only for computational feasibility but also for obtaining conceptual insights from complex systems. Here, we introduce an intuitive graphical approach to model reduction based on phase plane analysis. Timescale separation is identified by the degree of hysteresis observed in phase-loops, which guides a "concentration-clamp" procedure for estimating explicit algebraic relationships between species equilibrating on fast timescales. The primary advantages of this approach over Jacobian-based timescale decomposition are that: 1) it incorporates nonlinear system dynamics, and 2) it can be easily visualized, even directly from experimental data. We tested this graphical model reduction approach using a 25-variable model of cardiac β(1)-adrenergic signaling, obtaining 6- and 4-variable reduced models that retain good predictive capabilities even in response to new perturbations. These 6 signaling species appear to be optimal "kinetic biomarkers" of the overall β(1)-adrenergic pathway. The 6-variable reduced model is well suited for integration into multiscale models of heart function, and more generally, this graphical model reduction approach is readily applicable to a variety of other complex biological systems.
Graphical approach to model reduction for nonlinear biochemical networks.
Directory of Open Access Journals (Sweden)
David O Holland
Full Text Available Model reduction is a central challenge to the development and analysis of multiscale physiology models. Advances in model reduction are needed not only for computational feasibility but also for obtaining conceptual insights from complex systems. Here, we introduce an intuitive graphical approach to model reduction based on phase plane analysis. Timescale separation is identified by the degree of hysteresis observed in phase-loops, which guides a "concentration-clamp" procedure for estimating explicit algebraic relationships between species equilibrating on fast timescales. The primary advantages of this approach over Jacobian-based timescale decomposition are that: 1 it incorporates nonlinear system dynamics, and 2 it can be easily visualized, even directly from experimental data. We tested this graphical model reduction approach using a 25-variable model of cardiac β(1-adrenergic signaling, obtaining 6- and 4-variable reduced models that retain good predictive capabilities even in response to new perturbations. These 6 signaling species appear to be optimal "kinetic biomarkers" of the overall β(1-adrenergic pathway. The 6-variable reduced model is well suited for integration into multiscale models of heart function, and more generally, this graphical model reduction approach is readily applicable to a variety of other complex biological systems.
A discrete element modelling approach for block impacts on trees
Toe, David; Bourrier, Franck; Olmedo, Ignatio; Berger, Frederic
2015-04-01
These past few year rockfall models explicitly accounting for block shape, especially those using the Discrete Element Method (DEM), have shown a good ability to predict rockfall trajectories. Integrating forest effects into those models still remain challenging. This study aims at using a DEM approach to model impacts of blocks on trees and identify the key parameters controlling the block kinematics after the impact on a tree. A DEM impact model of a block on a tree was developed and validated using laboratory experiments. Then, key parameters were assessed using a global sensitivity analyse. Modelling the impact of a block on a tree using DEM allows taking into account large displacements, material non-linearities and contacts between the block and the tree. Tree stems are represented by flexible cylinders model as plastic beams sustaining normal, shearing, bending, and twisting loading. Root soil interactions are modelled using a rotation stiffness acting on the bending moment at the bottom of the tree and a limit bending moment to account for tree overturning. The crown is taken into account using an additional mass distribute uniformly on the upper part of the tree. The block is represented by a sphere. The contact model between the block and the stem consists of an elastic frictional model. The DEM model was validated using laboratory impact tests carried out on 41 fresh beech (Fagus Sylvatica) stems. Each stem was 1,3 m long with a diameter between 3 to 7 cm. Wood stems were clamped on a rigid structure and impacted by a 149 kg charpy pendulum. Finally an intensive simulation campaign of blocks impacting trees was done to identify the input parameters controlling the block kinematics after the impact on a tree. 20 input parameters were considered in the DEM simulation model : 12 parameters were related to the tree and 8 parameters to the block. The results highlight that the impact velocity, the stem diameter, and the block volume are the three input
Data Analysis A Model Comparison Approach, Second Edition
Judd, Charles M; Ryan, Carey S
2008-01-01
This completely rewritten classic text features many new examples, insights and topics including mediational, categorical, and multilevel models. Substantially reorganized, this edition provides a briefer, more streamlined examination of data analysis. Noted for its model-comparison approach and unified framework based on the general linear model, the book provides readers with a greater understanding of a variety of statistical procedures. This consistent framework, including consistent vocabulary and notation, is used throughout to develop fewer but more powerful model building techniques. T
A Model Management Approach for Co-Simulation Model Evaluation
Zhang, X.C.; Broenink, Johannes F.; Filipe, Joaquim; Kacprzyk, Janusz; Pina, Nuno
2011-01-01
Simulating formal models is a common means for validating the correctness of the system design and reduce the time-to-market. In most of the embedded control system design, multiple engineering disciplines and various domain-specific models are often involved, such as mechanical, control, software
Methodology and Results of Mathematical Modelling of Complex Technological Processes
Mokrova, Nataliya V.
2018-03-01
The methodology of system analysis allows us to draw a mathematical model of the complex technological process. The mathematical description of the plasma-chemical process was proposed. The importance the quenching rate and initial temperature decrease time was confirmed for producing the maximum amount of the target product. The results of numerical integration of the system of differential equations can be used to describe reagent concentrations, plasma jet rate and temperature in order to achieve optimal mode of hardening. Such models are applicable both for solving control problems and predicting future states of sophisticated technological systems.
Modeling vertical loads in pools resulting from fluid injection. [BWR
Energy Technology Data Exchange (ETDEWEB)
Lai, W.; McCauley, E.W.
1978-06-15
Table-top model experiments were performed to investigate pressure suppression pool dynamics effects due to a postulated loss-of-coolant accident (LOCA) for the Peachbottom Mark I boiling water reactor containment system. The results guided subsequent conduct of experiments in the /sup 1///sub 5/-scale facility and provided new insight into the vertical load function (VLF). Model experiments show an oscillatory VLF with the download typically double-spiked followed by a more gradual sinusoidal upload. The load function contains a high frequency oscillation superimposed on a low frequency one; evidence from measurements indicates that the oscillations are initiated by fluid dynamics phenomena.
Modeling vertical loads in pools resulting from fluid injection
International Nuclear Information System (INIS)
Lai, W.; McCauley, E.W.
1978-01-01
Table-top model experiments were performed to investigate pressure suppression pool dynamics effects due to a postulated loss-of-coolant accident (LOCA) for the Peachbottom Mark I boiling water reactor containment system. The results guided subsequent conduct of experiments in the 1 / 5 -scale facility and provided new insight into the vertical load function (VLF). Model experiments show an oscillatory VLF with the download typically double-spiked followed by a more gradual sinusoidal upload. The load function contains a high frequency oscillation superimposed on a low frequency one; evidence from measurements indicates that the oscillations are initiated by fluid dynamics phenomena
Some results on the dynamics generated by the Bazykin model
Directory of Open Access Journals (Sweden)
Georgescu, R M
2006-07-01
Full Text Available A predator-prey model formerly proposed by A. Bazykin et al. [Bifurcation diagrams of planar dynamical systems (1985] is analyzed in the case when two of the four parameters are kept fixed. Dynamics and bifurcation results are deduced by using the methods developed by D. K. Arrowsmith and C. M. Place [Ordinary differential equations (1982], S.-N. Chow et al. [Normal forms and bifurcation of planar fields (1994], Y. A. Kuznetsov [Elements of applied bifurcation theory (1998], and A. Georgescu [Dynamic bifurcation diagrams for some models in economics and biology (2004]. The global dynamic bifurcation diagram is constructed and graphically represented. The biological interpretation is presented, too.
Results of the eruptive column model inter-comparison study
Costa, Antonio; Suzuki, Yujiro; Cerminara, M.; Devenish, Ben J.; Esposti Ongaro, T.; Herzog, Michael; Van Eaton, Alexa; Denby, L.C.; Bursik, Marcus; de' Michieli Vitturi, Mattia; Engwell, S.; Neri, Augusto; Barsotti, Sara; Folch, Arnau; Macedonio, Giovanni; Girault, F.; Carazzo, G.; Tait, S.; Kaminski, E.; Mastin, Larry G.; Woodhouse, Mark J.; Phillips, Jeremy C.; Hogg, Andrew J.; Degruyter, Wim; Bonadonna, Costanza
2016-01-01
This study compares and evaluates one-dimensional (1D) and three-dimensional (3D) numerical models of volcanic eruption columns in a set of different inter-comparison exercises. The exercises were designed as a blind test in which a set of common input parameters was given for two reference eruptions, representing a strong and a weak eruption column under different meteorological conditions. Comparing the results of the different models allows us to evaluate their capabilities and target areas for future improvement. Despite their different formulations, the 1D and 3D models provide reasonably consistent predictions of some of the key global descriptors of the volcanic plumes. Variability in plume height, estimated from the standard deviation of model predictions, is within ~ 20% for the weak plume and ~ 10% for the strong plume. Predictions of neutral buoyancy level are also in reasonably good agreement among the different models, with a standard deviation ranging from 9 to 19% (the latter for the weak plume in a windy atmosphere). Overall, these discrepancies are in the range of observational uncertainty of column height. However, there are important differences amongst models in terms of local properties along the plume axis, particularly for the strong plume. Our analysis suggests that the simplified treatment of entrainment in 1D models is adequate to resolve the general behaviour of the weak plume. However, it is inadequate to capture complex features of the strong plume, such as large vortices, partial column collapse, or gravitational fountaining that strongly enhance entrainment in the lower atmosphere. We conclude that there is a need to more accurately quantify entrainment rates, improve the representation of plume radius, and incorporate the effects of column instability in future versions of 1D volcanic plume models.
Radiative effects of a CO2 increase: Results of a model comparison
International Nuclear Information System (INIS)
Luther, F.M.
1992-01-01
Many infrared (IR) radiative transfer models have been developed that range in complexity from line-by-line calculations to simplified parameterizations used in climate models and general circulation models. Assessment of the potential climatic effects of trace gases such as carbon dioxide requires first an evaluation of the radiative properties of each gas and determination of the perturbation to the radiative fluxes. The most detailed radiative transfer models are well suited for this application. The perturbed radiative fluxes lead to climatic effects that are evaluated using models that couple radiative, dynamic transport, and hydrological processes. Recently, chemical interactions have also been included in the assessments. It is desirable that a better understanding be developed of the differences in model approaches used by various modeling groups and how these differences affect model sensitivity to perturbations such as increased carbon dioxide. Since many factors affect model sensitivity, a practical approach is to start with a comparison of the basic physical processes without feedbacks and couplings, then to build in complexity. Because increases in carbon dioxide leads to radiative forcing, the treatment of radiative processes is a natural starting point for comparison. A comparison of infrared radiative transfer models has begun under the auspices of the US Department of Energy's Carbon Dioxide Research Program. The results of the IR model comparison will be included in the state-of-the-art report on climate modeling
A novel approach to modeling and diagnosing the cardiovascular system
Energy Technology Data Exchange (ETDEWEB)
Keller, P.E.; Kangas, L.J.; Hashem, S.; Kouzes, R.T. [Pacific Northwest Lab., Richland, WA (United States); Allen, P.A. [Life Link, Richland, WA (United States)
1995-07-01
A novel approach to modeling and diagnosing the cardiovascular system is introduced. A model exhibits a subset of the dynamics of the cardiovascular behavior of an individual by using a recurrent artificial neural network. Potentially, a model will be incorporated into a cardiovascular diagnostic system. This approach is unique in that each cardiovascular model is developed from physiological measurements of an individual. Any differences between the modeled variables and the variables of an individual at a given time are used for diagnosis. This approach also exploits sensor fusion to optimize the utilization of biomedical sensors. The advantage of sensor fusion has been demonstrated in applications including control and diagnostics of mechanical and chemical processes.
Initial CGE Model Results Summary Exogenous and Endogenous Variables Tests
Energy Technology Data Exchange (ETDEWEB)
Edwards, Brian Keith [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boero, Riccardo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rivera, Michael Kelly [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-08-07
The following discussion presents initial results of tests of the most recent version of the National Infrastructure Simulation and Analysis Center Dynamic Computable General Equilibrium (CGE) model developed by Los Alamos National Laboratory (LANL). The intent of this is to test and assess the model’s behavioral properties. The test evaluated whether the predicted impacts are reasonable from a qualitative perspective. This issue is whether the predicted change, be it an increase or decrease in other model variables, is consistent with prior economic intuition and expectations about the predicted change. One of the purposes of this effort is to determine whether model changes are needed in order to improve its behavior qualitatively and quantitatively.
Box-wing model approach for solar radiation pressure modelling in a multi-GNSS scenario
Tobias, Guillermo; Jesús García, Adrián
2016-04-01
The solar radiation pressure force is the largest orbital perturbation after the gravitational effects and the major error source affecting GNSS satellites. A wide range of approaches have been developed over the years for the modelling of this non gravitational effect as part of the orbit determination process. These approaches are commonly divided into empirical, semi-analytical and analytical, where their main difference relies on the amount of knowledge of a-priori physical information about the properties of the satellites (materials and geometry) and their attitude. It has been shown in the past that the pre-launch analytical models fail to achieve the desired accuracy mainly due to difficulties in the extrapolation of the in-orbit optical and thermic properties, the perturbations in the nominal attitude law and the aging of the satellite's surfaces, whereas empirical models' accuracies strongly depend on the amount of tracking data used for deriving the models, and whose performances are reduced as the area to mass ratio of the GNSS satellites increases, as it happens for the upcoming constellations such as BeiDou and Galileo. This paper proposes to use basic box-wing model for Galileo complemented with empirical parameters, based on the limited available information about the Galileo satellite's geometry. The satellite is modelled as a box, representing the satellite bus, and a wing representing the solar panel. The performance of the model will be assessed for GPS, GLONASS and Galileo constellations. The results of the proposed approach have been analyzed over a one year period. In order to assess the results two different SRP models have been used. Firstly, the proposed box-wing model and secondly, the new CODE empirical model, ECOM2. The orbit performances of both models are assessed using Satellite Laser Ranging (SLR) measurements, together with the evaluation of the orbit prediction accuracy. This comparison shows the advantages and disadvantages of
Abla, Adib A; Benet, Arnau; Lawton, Michael T
2014-09-01
Pontine cavernous malformations (CMs) located on a peripheral pontine surface or the fourth ventricular floor are resectable lesions, but those deep within the pons away from a pial surface are typically observed. However, the anterior bulge of the pons formed by the brachium pontis creates a unique entry point for access to deep pontine lesions from below, working upward through the pontomedullary sulcus. We developed a transpontomedullary sulcus (TPMS) approach to these lesions. The TPMS approach used the far lateral craniotomy and upper vagoaccessory triangle to define the surgical corridor. The entry point was above the olive, lateral to the pyramidal tracts and cranial nerve (CN) VI, above the preolivary sulcus and CN XII, and medial to CNs VII and VIII and CNs IX through XI. Four patients underwent this approach. All presented with hemorrhage and CN VI palsies. All pontine CMs were resected completely. Three patients were improved or unchanged, with good outcomes (modified Rankin Scale score ≤2) in all patients. The central pons remains difficult territory to access, and new surgical corridors are needed. The bulging underbelly of the pons allows access to pontine lesions deep to the pial surface from below. The far lateral TPMS approach is a novel and more direct alternative to the retrosigmoid transmiddle cerebellar peduncle approach. Unlike the retrosigmoid approach, the TPMS approach requires minimal parenchymal transgression and uses a brainstem entry point medial to most lower CNs. Favorable results demonstrate the feasibility of resecting pontine CMs that might have been previously deemed unresectable.
A New Approach to Modeling Jupiter's Magnetosphere
Fukazawa, K.; Katoh, Y.; Walker, R. J.; Kimura, T.; Tsuchiya, F.; Murakami, G.; Kita, H.; Tao, C.; Murata, K. T.
2017-12-01
The scales in planetary magnetospheres range from 10s of planetary radii to kilometers. For a number of years we have studied the magnetospheres of Jupiter and Saturn by using 3-dimensional magnetohydrodynamic (MHD) simulations. However, we have not been able to reach even the limits of the MHD approximation because of the large amount of computer resources required. Recently thanks to the progress in supercomputer systems, we have obtained the capability to simulate Jupiter's magnetosphere with 1000 times the number of grid points used in our previous simulations. This has allowed us to combine the high resolution global simulation with a micro-scale simulation of the Jovian magnetosphere. In particular we can combine a hybrid (kinetic ions and fluid electrons) simulation with the MHD simulation. In addition, the new capability enables us to run multi-parameter survey simulations of the Jupiter-solar wind system. In this study we performed a high-resolution simulation of Jovian magnetosphere to connect with the hybrid simulation, and lower resolution simulations under the various solar wind conditions to compare with Hisaki and Juno observations. In the high-resolution simulation we used a regular Cartesian gird with 0.15 RJ grid spacing and placed the inner boundary at 7 RJ. From these simulation settings, we provide the magnetic field out to around 20 RJ from Jupiter as a background field for the hybrid simulation. For the first time we have been able to resolve Kelvin Helmholtz waves on the magnetopause. We have investigated solar wind dynamic pressures between 0.01 and 0.09 nPa for a number of IMF values. These simulation data are open for the registered users to download the raw data. We have compared the results of these simulations with Hisaki auroral observations.
Muenich, R. L.; Kalcic, M. M.; Teshager, A. D.; Long, C. M.; Wang, Y. C.; Scavia, D.
2017-12-01
Thanks to the availability of open-source software, online tutorials, and advanced software capabilities, watershed modeling has expanded its user-base and applications significantly in the past thirty years. Even complicated models like the Soil and Water Assessment Tool (SWAT) are being used and documented in hundreds of peer-reviewed publications each year, and likely more applied in practice. These models can help improve our understanding of present, past, and future conditions, or analyze important "what-if" management scenarios. However, baseline data and methods are often adopted and applied without rigorous testing. In multiple collaborative projects, we have evaluated the influence of some of these common approaches on model results. Specifically, we examined impacts of baseline data and assumptions involved in manure application, combined sewer overflows, and climate data incorporation across multiple watersheds in the Western Lake Erie Basin. In these efforts, we seek to understand the impact of using typical modeling data and assumptions, versus using improved data and enhanced assumptions on model outcomes and thus ultimately, study conclusions. We provide guidance for modelers as they adopt and apply data and models for their specific study region. While it is difficult to quantitatively assess the full uncertainty surrounding model input data and assumptions, recognizing the impacts of model input choices is important when considering actions at the both the field and watershed scales.
Generic model for calculating carbon footprint of milk using four different LCA modelling approaches
DEFF Research Database (Denmark)
Dalgaard, Randi; Schmidt, Jannick Højrup; Flysjö, Anna
2014-01-01
is LCA. The model includes switches that enables for, within the same scope, transforming the results to comply with 1) consequential LCA, 2) allocation/average modelling (or ‘attributional LCA’), 3) PAS 2050 and 4) The International Dairy Federations (IDF) guide to standard life cycle assessment......The aim of the study is to develop a tool, which can be used for calculation of carbon footprint (using a life cycle assessment (LCA) approach) of milk both at a farm level and at a national level. The functional unit is ‘1 kg energy corrected milk (ECM) at farm gate’ and the applied methodology...
Stabilization Approaches for Linear and Nonlinear Reduced Order Models
Rezaian, Elnaz; Wei, Mingjun
2017-11-01
It has been a major concern to establish reduced order models (ROMs) as reliable representatives of the dynamics inherent in high fidelity simulations, while fast computation is achieved. In practice it comes to stability and accuracy of ROMs. Given the inviscid nature of Euler equations it becomes more challenging to achieve stability, especially where moving discontinuities exist. Originally unstable linear and nonlinear ROMs are stabilized here by two approaches. First, a hybrid method is developed by integrating two different stabilization algorithms. At the same time, symmetry inner product is introduced in the generation of ROMs for its known robust behavior for compressible flows. Results have shown a notable improvement in computational efficiency and robustness compared to similar approaches. Second, a new stabilization algorithm is developed specifically for nonlinear ROMs. This method adopts Particle Swarm Optimization to enforce a bounded ROM response for minimum discrepancy between the high fidelity simulation and the ROM outputs. Promising results are obtained in its application on the nonlinear ROM of an inviscid fluid flow with discontinuities. Supported by ARL.
A model-driven approach to information security compliance
Correia, Anacleto; Gonçalves, António; Teodoro, M. Filomena
2017-06-01
The availability, integrity and confidentiality of information are fundamental to the long-term survival of any organization. Information security is a complex issue that must be holistically approached, combining assets that support corporate systems, in an extended network of business partners, vendors, customers and other stakeholders. This paper addresses the conception and implementation of information security systems, conform the ISO/IEC 27000 set of standards, using the model-driven approach. The process begins with the conception of a domain level model (computation independent model) based on information security vocabulary present in the ISO/IEC 27001 standard. Based on this model, after embedding in the model mandatory rules for attaining ISO/IEC 27001 conformance, a platform independent model is derived. Finally, a platform specific model serves the base for testing the compliance of information security systems with the ISO/IEC 27000 set of standards.
Mathematical models for therapeutic approaches to control HIV disease transmission
Roy, Priti Kumar
2015-01-01
The book discusses different therapeutic approaches based on different mathematical models to control the HIV/AIDS disease transmission. It uses clinical data, collected from different cited sources, to formulate the deterministic as well as stochastic mathematical models of HIV/AIDS. It provides complementary approaches, from deterministic and stochastic points of view, to optimal control strategy with perfect drug adherence and also tries to seek viewpoints of the same issue from different angles with various mathematical models to computer simulations. The book presents essential methods and techniques for students who are interested in designing epidemiological models on HIV/AIDS. It also guides research scientists, working in the periphery of mathematical modeling, and helps them to explore a hypothetical method by examining its consequences in the form of a mathematical modelling and making some scientific predictions. The model equations, mathematical analysis and several numerical simulations that are...
Interaction between subducting plates: results from numerical and analogue modeling
Kiraly, Agnes; Capitanio, Fabio A.; Funiciello, Francesca; Faccenna, Claudio
2016-04-01
The tectonic setting of the Alpine-Mediterranean area is achieved during the late Cenozoic subduction, collision and suturing of several oceanic fragments and continental blocks. In this stage, processes such as interactions among subducting slabs, slab migrations and related mantle flow played a relevant role on the resulting tectonics. Here, we use numerical models to first address the mantle flow characteristic in 3D. During the subduction of a single plate the strength of the return flow strongly depends on the slab pull force, that is on the plate's buoyancy, however the physical properties of the slab, such as density, viscosity or width, do not affect largely the morphology of the toroidal cell. Instead, dramatic effects on the geometry and the dynamics of the toroidal cell result in models where the thickness of the mantle is varied. The vertical component of the vorticity vector is used to define the characteristic size of the toroidal cell, which is ~1.2-1.3 times the mantle depth. This latter defines the range of viscous stress propagation through the mantle and consequent interactions with other slabs. We thus further investigate on this setup where two separate lithospheric plates subduct in opposite sense, developing opposite polarities and convergent slab retreat, and model different initial sideways distance between the plates. The stress profiles in time illustrate that the plates interacts when slabs are at the characteristic distance and the two slabs toroidal cells merge. Increased stress and delayed slab migrations are the results. Analogue models of double-sided subduction show similar maximum distance and allow testing the additional role of stress propagated through the plates. We use a silicon plate subducting on its two opposite margins, which is either homogeneous or comprises oceanic and continental lithospheres, differing in buoyancy. The modeling results show that the double-sided subduction is strongly affected by changes in plate
Nonlinear regression modeling of nutrient loads in streams: A Bayesian approach
Qian, S.S.; Reckhow, K.H.; Zhai, J.; McMahon, G.
2005-01-01
A Bayesian nonlinear regression modeling method is introduced and compared with the least squares method for modeling nutrient loads in stream networks. The objective of the study is to better model spatial correlation in river basin hydrology and land use for improving the model as a forecasting tool. The Bayesian modeling approach is introduced in three steps, each with a more complicated model and data error structure. The approach is illustrated using a data set from three large river basins in eastern North Carolina. Results indicate that the Bayesian model better accounts for model and data uncertainties than does the conventional least squares approach. Applications of the Bayesian models for ambient water quality standards compliance and TMDL assessment are discussed. Copyright 2005 by the American Geophysical Union.
First experiments results about the engineering model of Rapsodie
International Nuclear Information System (INIS)
Chalot, A.; Ginier, R.; Sauvage, M.
1964-01-01
This report deals with the first series of experiments carried out on the engineering model of Rapsodie and on an associated sodium facility set in a laboratory hall of Cadarache. It conveys more precisely: 1/ - The difficulties encountered during the erection and assembly of the engineering model and a compilation of the results of the first series of experiments and tests carried out on this installation (loading of the subassemblies preheating, thermal chocks...). 2/ - The experiments and tests carried out on the two prototypes control rod drive mechanisms which brought to the choice for the design of the definitive drive mechanism. As a whole, the results proved the validity of the general design principles adopted for Rapsodie. (authors) [fr
Scientific Approach and Inquiry Learning Model in the Topic of Buffer Solution: A Content Analysis
Kusumaningrum, I. A.; Ashadi, A.; Indriyanti, N. Y.
2017-09-01
Many concepts in buffer solution cause student’s misconception. Understanding science concepts should apply the scientific approach. One of learning models which is suitable with this approach is inquiry. Content analysis was used to determine textbook compatibility with scientific approach and inquiry learning model in the concept of buffer solution. By using scientific indicator tools (SIT) and Inquiry indicator tools (IIT), we analyzed three chemistry textbooks grade 11 of senior high school labeled as P, Q, and R. We described how textbook compatibility with scientific approach and inquiry learning model in the concept of buffer solution. The results show that textbook P and Q were very poor and book R was sufficient because the textbook still in procedural level. Chemistry textbooks used at school are needed to be improved in term of scientific approach and inquiry learning model. The result of these analyses might be of interest in order to write future potential textbooks.
Workshop to transfer VELMA watershed model results to ...
An EPA Western Ecology Division (WED) watershed modeling team has been working with the Snoqualmie Tribe Environmental and Natural Resources Department to develop VELMA watershed model simulations of the effects of historical and future restoration and land use practices on streamflow, stream temperature, and other habitat characteristics affecting threatened salmon populations in the 100 square mile Tolt River watershed in Washington state. To date, the WED group has fully calibrated the watershed model to simulate Tolt River flows with a high degree of accuracy under current and historical conditions and practices, and is in the process of simulating long-term responses to specific watershed restoration practices conducted by the Snoqualmie Tribe and partners. On July 20-21 WED Researchers Bob McKane, Allen Brookes and ORISE Fellow Jonathan Halama will be attending a workshop at the Tolt River site in Carnation, WA, to present and discuss modeling results with the Snoqualmie Tribe and other Tolt River watershed stakeholders and land managers, including the Washington Departments of Ecology and Natural Resources, U.S. Forest Service, City of Seattle, King County, and representatives of the Northwest Indian Fisheries Commission. The workshop is being co-organized by the Snoqualmie Tribe, EPA Region 10 and WED. The purpose of this 2-day workshop is two-fold. First, on Day 1, the modeling team will perform its second site visit to the watershed, this time focus
Meteorological uncertainty of atmospheric dispersion model results (MUD)
International Nuclear Information System (INIS)
Havskov Soerensen, J.; Amstrup, B.; Feddersen, H.
2013-08-01
The MUD project addresses assessment of uncertainties of atmospheric dispersion model predictions, as well as possibilities for optimum presentation to decision makers. Previously, it has not been possible to estimate such uncertainties quantitatively, but merely to calculate the 'most likely' dispersion scenario. However, recent developments in numerical weather prediction (NWP) include probabilistic forecasting techniques, which can be utilised also for long-range atmospheric dispersion models. The ensemble statistical methods developed and applied to NWP models aim at describing the inherent uncertainties of the meteorological model results. These uncertainties stem from e.g. limits in meteorological observations used to initialise meteorological forecast series. By perturbing e.g. the initial state of an NWP model run in agreement with the available observational data, an ensemble of meteorological forecasts is produced from which uncertainties in the various meteorological parameters are estimated, e.g. probabilities for rain. Corresponding ensembles of atmospheric dispersion can now be computed from which uncertainties of predicted radionuclide concentration and deposition patterns can be derived. (Author)
BUSINESS MODEL IN ELECTRICITY INDUSTRY USING BUSINESS MODEL CANVAS APPROACH; THE CASE OF PT. XYZ
Directory of Open Access Journals (Sweden)
Achmad Arief Wicaksono
2017-01-01
Full Text Available The magnitude of opportunities and project values of electricity system in Indonesia encourages PT. XYZ to develop its business in electrical sector which requires business development strategies. This study aims to identify company's business model using Business Model Canvas approach, formulate business development strategy alternatives, and determine the prioritized business development strategy which is appropriate to the manufacturing business model for PT. XYZ. This study utilized a descriptive approach and the nine elements of the Business Model Canvas. Alternative formulation and priority determination of the strategies were obtained by using Strengths, Weaknesses, Opportunities, Threats (SWOT analysis and pairwise comparison. The results of this study are the improvement of Business Model Canvas on the elements of key resources, key activities, key partners and customer segment. In terms of SWOT analysis on the nine elements of the Business Model Canvas for the first business development, the results show an expansion on the power plant construction project as the main contractor, an increase in sales in its core business in supporting equipment industry of oil and gas, a development in the second business i.e. an investment in the electricity sector as an independent renewable emery-based power producer. On its first business development, PT. XYZ selected three Business Model Canvas elements which become the priorities of the company i.e. key resources weighing 0.252, key activities weighing 0.240, and key partners weighing 0.231. On its second business development, the company selected three elements to become their the priorities i.e. key partners weighing 0.225, customer segments weighing 0.217, and key resources weighing 0.215.Keywords: business model canvas, SWOT, pairwise comparison, business model
Presenting results of software model checker via debugging interface
Kohan, Tomáš
2012-01-01
Title: Presenting results of software model checker via debugging interface Author: Tomáš Kohan Department: Department of Software Engineering Supervisor of the master thesis: RNDr. Ondřej Šerý, Ph.D., Department of Distributed and Dependable Systems Abstract: This thesis is devoted to design and implementation of the new debugging interface of the Java PathFinder application. As a suitable inte- face container was selected the Eclipse development environment. The created interface should vis...
Building a Global Groundwater Model fromScratch - Concepts and Results
Reinecke, R.; Song, Q.; Foglia, L.; Mehl, S.; Doll, P. M.
2016-12-01
To represent groundwater-surface water interactions as well as the impact of capillary rise on evapotranspiration in global-scale hydrological models, it is necessary to simulate the location and temporal variation of the groundwater table. This requires to replace simulation of groundwater dynamics by calculating groundwater storage variations in individual grid cells (independent from the storage variation in neighboring cells) by hydraulic head gradient-based groundwater modeling. Based on the experience of two research groups who have published different approaches for global-scale groundwater modeling, we present first results of our effort to develop a transient global groundwater model that is to replace the simple storage-based ground-water module of the global hydrological model WaterGAP. The following three technical and conceptual aspects of this endeavour arediscussed: (1) A software engineering approach to build a new hydraulic head based global groundwater model from scratch with the goal of maximizing performance and extensibility. (2) Comparison to other model approaches and their inherent problems. (3) Global-data deficits and how to deal with them. Furthermore, this poster presents and discusses first results and provides an outlook on future developments.
Dynamics and control of quadcopter using linear model predictive control approach
Islam, M.; Okasha, M.; Idres, M. M.
2017-12-01
This paper investigates the dynamics and control of a quadcopter using the Model Predictive Control (MPC) approach. The dynamic model is of high fidelity and nonlinear, with six degrees of freedom that include disturbances and model uncertainties. The control approach is developed based on MPC to track different reference trajectories ranging from simple ones such as circular to complex helical trajectories. In this control technique, a linearized model is derived and the receding horizon method is applied to generate the optimal control sequence. Although MPC is computer expensive, it is highly effective to deal with the different types of nonlinearities and constraints such as actuators’ saturation and model uncertainties. The MPC parameters (control and prediction horizons) are selected by trial-and-error approach. Several simulation scenarios are performed to examine and evaluate the performance of the proposed control approach using MATLAB and Simulink environment. Simulation results show that this control approach is highly effective to track a given reference trajectory.
Farquharson, C.; Long, J.; Lu, X.; Lelievre, P. G.
2017-12-01
Real-life geology is complex, and so, even when allowing for the diffusive, low resolution nature of geophysical electromagnetic methods, we need Earth models that can accurately represent this complexity when modelling and inverting electromagnetic data. This is particularly the case for the scales, detail and conductivity contrasts involved in mineral and hydrocarbon exploration and development, but also for the larger scale of lithospheric studies. Unstructured tetrahedral meshes provide a flexible means of discretizing a general, arbitrary Earth model. This is important when wanting to integrate a geophysical Earth model with a geological Earth model parameterized in terms of surfaces. Finite-element and finite-volume methods can be derived for computing the electric and magnetic fields in a model parameterized using an unstructured tetrahedral mesh. A number of such variants have been proposed and have proven successful. However, the efficiency and accuracy of these methods can be affected by the "quality" of the tetrahedral discretization, that is, how many of the tetrahedral cells in the mesh are long, narrow and pointy. This is particularly the case if one wants to use an iterative technique to solve the resulting linear system of equations. One approach to deal with this issue is to develop sophisticated model and mesh building and manipulation capabilities in order to ensure that any mesh built from geological information is of sufficient quality for the electromagnetic modelling. Another approach is to investigate other methods of synthesizing the electromagnetic fields. One such example is a "meshfree" approach in which the electromagnetic fields are synthesized using a mesh that is distinct from the mesh used to parameterized the Earth model. There are then two meshes, one describing the Earth model and one used for the numerical mathematics of computing the fields. This means that there are no longer any quality requirements on the model mesh, which
Review of Current Standard Model Results in ATLAS
Brandt, Gerhard; The ATLAS collaboration
2018-01-01
This talk highlights results selected from the Standard Model research programme of the ATLAS Collaboration at the Large Hadron Collider. Results using data from $p-p$ collisions at $\\sqrt{s}=7,8$~TeV in LHC Run-1 as well as results using data at $\\sqrt{s}=13$~TeV in LHC Run-2 are covered. The status of cross section measurements from soft QCD processes and jet production as well as photon production are presented. The presentation extends to vector boson production with associated jets. Precision measurements of the production of $W$ and $Z$ bosons, including a first measurement of the mass of the $W$ bosons, $m_W$, are discussed. The programme to measure electroweak processes with di-boson and tri-boson final states is outlined. All presented measurements are compatible with Standard Model descriptions and allow to further constrain it. In addition they allow to probe new physics which would manifest through extra gauge couplings, or Standard Model gauge couplings deviating from their predicted value.
Benchmarking of computer codes and approaches for modeling exposure scenarios
International Nuclear Information System (INIS)
Seitz, R.R.; Rittmann, P.D.; Wood, M.I.; Cook, J.R.
1994-08-01
The US Department of Energy Headquarters established a performance assessment task team (PATT) to integrate the activities of DOE sites that are preparing performance assessments for the disposal of newly generated low-level waste. The PATT chartered a subteam with the task of comparing computer codes and exposure scenarios used for dose calculations in performance assessments. This report documents the efforts of the subteam. Computer codes considered in the comparison include GENII, PATHRAE-EPA, MICROSHIELD, and ISOSHLD. Calculations were also conducted using spreadsheets to provide a comparison at the most fundamental level. Calculations and modeling approaches are compared for unit radionuclide concentrations in water and soil for the ingestion, inhalation, and external dose pathways. Over 30 tables comparing inputs and results are provided
Validation of a Parametric Approach for 3d Fortification Modelling: Application to Scale Models
Jacquot, K.; Chevrier, C.; Halin, G.
2013-02-01
Parametric modelling approach applied to cultural heritage virtual representation is a field of research explored for years since it can address many limitations of digitising tools. For example, essential historical sources for fortification virtual reconstructions like plans-reliefs have several shortcomings when they are scanned. To overcome those problems, knowledge based-modelling can be used: knowledge models based on the analysis of theoretical literature of a specific domain such as bastioned fortification treatises can be the cornerstone of the creation of a parametric library of fortification components. Implemented in Grasshopper, these components are manually adjusted on the data available (i.e. 3D surveys of plans-reliefs or scanned maps). Most of the fortification area is now modelled and the question of accuracy assessment is raised. A specific method is used to evaluate the accuracy of the parametric components. The results of the assessment process will allow us to validate the parametric approach. The automation of the adjustment process can finally be planned. The virtual model of fortification is part of a larger project aimed at valorising and diffusing a very unique cultural heritage item: the collection of plans-reliefs. As such, knowledge models are precious assets when automation and semantic enhancements will be considered.
Interoperable transactions in business models: A structured approach
Weigand, H.; Verharen, E.; Dignum, F.P.M.
1996-01-01
Recent database research has given much attention to the specification of "flexible" transactions that can be used in interoperable systems. Starting from a quite different angle, Business Process Modelling has approached the area of communication modelling as well (the Language/Action
A Model-Driven Approach to e-Course Management
Savic, Goran; Segedinac, Milan; Milenkovic, Dušica; Hrin, Tamara; Segedinac, Mirjana
2018-01-01
This paper presents research on using a model-driven approach to the development and management of electronic courses. We propose a course management system which stores a course model represented as distinct machine-readable components containing domain knowledge of different course aspects. Based on this formally defined platform-independent…
Modeling Alaska boreal forests with a controlled trend surface approach
Mo Zhou; Jingjing Liang
2012-01-01
An approach of Controlled Trend Surface was proposed to simultaneously take into consideration large-scale spatial trends and nonspatial effects. A geospatial model of the Alaska boreal forest was developed from 446 permanent sample plots, which addressed large-scale spatial trends in recruitment, diameter growth, and mortality. The model was tested on two sets of...
Towards modeling future energy infrastructures - the ELECTRA system engineering approach
DEFF Research Database (Denmark)
Uslar, Mathias; Heussen, Kai
2016-01-01
of the IEC 62559 use case template as well as needed changes to cope particularly with the aspects of controller conflicts and Greenfield technology modeling. From the original envisioned use of the standards, we show a possible transfer on how to properly deal with a Greenfield approach when modeling....
Child human model development: a hybrid validation approach
Forbes, P.A.; Rooij, L. van; Rodarius, C.; Crandall, J.
2008-01-01
The current study presents a development and validation approach of a child human body model that will help understand child impact injuries and improve the biofidelity of child anthropometric test devices. Due to the lack of fundamental child biomechanical data needed to fully develop such models a
Refining the Committee Approach and Uncertainty Prediction in Hydrological Modelling
Kayastha, N.
2014-01-01
Due to the complexity of hydrological systems a single model may be unable to capture the full range of a catchment response and accurately predict the streamflows. The multi modelling approach opens up possibilities for handling such difficulties and allows improve the predictive capability of
Refining the committee approach and uncertainty prediction in hydrological modelling
Kayastha, N.
2014-01-01
Due to the complexity of hydrological systems a single model may be unable to capture the full range of a catchment response and accurately predict the streamflows. The multi modelling approach opens up possibilities for handling such difficulties and allows improve the predictive capability of
Product Trial Processing (PTP): a model approach from ...
African Journals Online (AJOL)
Product Trial Processing (PTP): a model approach from theconsumer's perspective. ... Global Journal of Social Sciences ... Among the constructs used in the model of consumer's processing of product trail includes; experiential and non- experiential attributes, perceived validity of product trial, consumer perceived expertise, ...
A MIXTURE LIKELIHOOD APPROACH FOR GENERALIZED LINEAR-MODELS
WEDEL, M; DESARBO, WS
1995-01-01
A mixture model approach is developed that simultaneously estimates the posterior membership probabilities of observations to a number of unobservable groups or latent classes, and the parameters of a generalized linear model which relates the observations, distributed according to some member of
Challenges in validating model results for first year ice
Melsom, Arne; Eastwood, Steinar; Xie, Jiping; Aaboe, Signe; Bertino, Laurent
2017-04-01
In order to assess the quality of model results for the distribution of first year ice, a comparison with a product based on observations from satellite-borne instruments has been performed. Such a comparison is not straightforward due to the contrasting algorithms that are used in the model product and the remote sensing product. The implementation of the validation is discussed in light of the differences between this set of products, and validation results are presented. The model product is the daily updated 10-day forecast from the Arctic Monitoring and Forecasting Centre in CMEMS. The forecasts are produced with the assimilative ocean prediction system TOPAZ. Presently, observations of sea ice concentration and sea ice drift are introduced in the assimilation step, but data for sea ice thickness and ice age (or roughness) are not included. The model computes the age of the ice by recording and updating the time passed after ice formation as sea ice grows and deteriorates as it is advected inside the model domain. Ice that is younger than 365 days is classified as first year ice. The fraction of first-year ice is recorded as a tracer in each grid cell. The Ocean and Sea Ice Thematic Assembly Centre in CMEMS redistributes a daily product from the EUMETSAT OSI SAF of gridded sea ice conditions which include "ice type", a representation of the separation of regions between those infested by first year ice, and those infested by multi-year ice. The ice type is parameterized based on data for the gradient ratio GR(19,37) from SSMIS observations, and from the ASCAT backscatter parameter. This product also includes information on ambiguity in the processing of the remote sensing data, and the product's confidence level, which have a strong seasonal dependency.
Hybrid empirical--theoretical approach to modeling uranium adsorption
Energy Technology Data Exchange (ETDEWEB)
Hull, Larry C.; Grossman, Christopher; Fjeld, Robert A.; Coates, John T.; Elzerman, Alan W
2004-05-01
An estimated 330 metric tons of U are buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of U transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of U fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms were measured for 14 sediment samples collected from sedimentary interbeds underlying the SDA. The adsorption data were fit with a Freundlich isotherm. The Freundlich n parameter is statistically identical for all 14 sediment samples and the Freundlich K{sub f} parameter is correlated to sediment surface area (r{sup 2}=0.80). These findings suggest an efficient approach to material characterization and implementation of a spatially variable reactive transport model that requires only the measurement of sediment surface area. To expand the potential applicability of the measured isotherms, a model is derived from the empirical observations by incorporating concepts from surface complexation theory to account for the effects of solution chemistry. The resulting model is then used to predict the range of adsorption conditions to be expected in the vadose zone at the SDA based on the range in measured pore water chemistry. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth.
Hybrid empirical--theoretical approach to modeling uranium adsorption
International Nuclear Information System (INIS)
Hull, Larry C.; Grossman, Christopher; Fjeld, Robert A.; Coates, John T.; Elzerman, Alan W.
2004-01-01
An estimated 330 metric tons of U are buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of U transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of U fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms were measured for 14 sediment samples collected from sedimentary interbeds underlying the SDA. The adsorption data were fit with a Freundlich isotherm. The Freundlich n parameter is statistically identical for all 14 sediment samples and the Freundlich K f parameter is correlated to sediment surface area (r 2 =0.80). These findings suggest an efficient approach to material characterization and implementation of a spatially variable reactive transport model that requires only the measurement of sediment surface area. To expand the potential applicability of the measured isotherms, a model is derived from the empirical observations by incorporating concepts from surface complexation theory to account for the effects of solution chemistry. The resulting model is then used to predict the range of adsorption conditions to be expected in the vadose zone at the SDA based on the range in measured pore water chemistry. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth
MASKED AREAS IN SHEAR PEAK STATISTICS: A FORWARD MODELING APPROACH
Energy Technology Data Exchange (ETDEWEB)
Bard, D. [KIPAC, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Kratochvil, J. M. [Astrophysics and Cosmology Research Unit, University of KwaZulu-Natal, Westville, Durban 4000 (South Africa); Dawson, W., E-mail: djbard@slac.stanford.edu [Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, CA 94550 (United States)
2016-03-10
The statistics of shear peaks have been shown to provide valuable cosmological information beyond the power spectrum, and will be an important constraint of models of cosmology in forthcoming astronomical surveys. Surveys include masked areas due to bright stars, bad pixels etc., which must be accounted for in producing constraints on cosmology from shear maps. We advocate a forward-modeling approach, where the impacts of masking and other survey artifacts are accounted for in the theoretical prediction of cosmological parameters, rather than correcting survey data to remove them. We use masks based on the Deep Lens Survey, and explore the impact of up to 37% of the survey area being masked on LSST and DES-scale surveys. By reconstructing maps of aperture mass the masking effect is smoothed out, resulting in up to 14% smaller statistical uncertainties compared to simply reducing the survey area by the masked area. We show that, even in the presence of large survey masks, the bias in cosmological parameter estimation produced in the forward-modeling process is ≈1%, dominated by bias caused by limited simulation volume. We also explore how this potential bias scales with survey area and evaluate how much small survey areas are impacted by the differences in cosmological structure in the data and simulated volumes, due to cosmic variance.
A Dynamic Approach to Modeling Dependence Between Human Failure Events
Energy Technology Data Exchange (ETDEWEB)
Boring, Ronald Laurids [Idaho National Laboratory
2015-09-01
In practice, most HRA methods use direct dependence from THERP—the notion that error be- gets error, and one human failure event (HFE) may increase the likelihood of subsequent HFEs. In this paper, we approach dependence from a simulation perspective in which the effects of human errors are dynamically modeled. There are three key concepts that play into this modeling: (1) Errors are driven by performance shaping factors (PSFs). In this context, the error propagation is not a result of the presence of an HFE yielding overall increases in subsequent HFEs. Rather, it is shared PSFs that cause dependence. (2) PSFs have qualities of lag and latency. These two qualities are not currently considered in HRA methods that use PSFs. Yet, to model the effects of PSFs, it is not simply a matter of identifying the discrete effects of a particular PSF on performance. The effects of PSFs must be considered temporally, as the PSFs will have a range of effects across the event sequence. (3) Finally, there is the concept of error spilling. When PSFs are activated, they not only have temporal effects but also lateral effects on other PSFs, leading to emergent errors. This paper presents the framework for tying together these dynamic dependence concepts.
Parameter Estimation of Structural Equation Modeling Using Bayesian Approach
Directory of Open Access Journals (Sweden)
Dewi Kurnia Sari
2016-05-01
Full Text Available Leadership is a process of influencing, directing or giving an example of employees in order to achieve the objectives of the organization and is a key element in the effectiveness of the organization. In addition to the style of leadership, the success of an organization or company in achieving its objectives can also be influenced by the commitment of the organization. Where organizational commitment is a commitment created by each individual for the betterment of the organization. The purpose of this research is to obtain a model of leadership style and organizational commitment to job satisfaction and employee performance, and determine the factors that influence job satisfaction and employee performance using SEM with Bayesian approach. This research was conducted at Statistics FNI employees in Malang, with 15 people. The result of this study showed that the measurement model, all significant indicators measure each latent variable. Meanwhile in the structural model, it was concluded there are a significant difference between the variables of Leadership Style and Organizational Commitment toward Job Satisfaction directly as well as a significant difference between Job Satisfaction on Employee Performance. As for the influence of Leadership Style and variable Organizational Commitment on Employee Performance directly declared insignificant.
Meta-analysis a structural equation modeling approach
Cheung, Mike W-L
2015-01-01
Presents a novel approach to conducting meta-analysis using structural equation modeling. Structural equation modeling (SEM) and meta-analysis are two powerful statistical methods in the educational, social, behavioral, and medical sciences. They are often treated as two unrelated topics in the literature. This book presents a unified framework on analyzing meta-analytic data within the SEM framework, and illustrates how to conduct meta-analysis using the metaSEM package in the R statistical environment. Meta-Analysis: A Structural Equation Modeling Approach begins by introducing the impo
A study of multidimensional modeling approaches for data warehouse
Yusof, Sharmila Mat; Sidi, Fatimah; Ibrahim, Hamidah; Affendey, Lilly Suriani
2016-08-01
Data warehouse system is used to support the process of organizational decision making. Hence, the system must extract and integrate information from heterogeneous data sources in order to uncover relevant knowledge suitable for decision making process. However, the development of data warehouse is a difficult and complex process especially in its conceptual design (multidimensional modeling). Thus, there have been various approaches proposed to overcome the difficulty. This study surveys and compares the approaches of multidimensional modeling and highlights the issues, trend and solution proposed to date. The contribution is on the state of the art of the multidimensional modeling design.
Numerical linked-cluster approach to quantum lattice models.
Rigol, Marcos; Bryant, Tyler; Singh, Rajiv R P
2006-11-03
We present a novel algorithm that allows one to obtain temperature dependent properties of quantum lattice models in the thermodynamic limit from exact diagonalization of small clusters. Our numerical linked-cluster approach provides a systematic framework to assess finite-size effects and is valid for any quantum lattice model. Unlike high temperature expansions, which have a finite radius of convergence in inverse temperature, these calculations are accurate at all temperatures provided the range of correlations is finite. We illustrate the power of our approach studying spin models on kagomé, triangular, and square lattices.
Directory of Open Access Journals (Sweden)
Jose Carlos Lynch
2016-05-01
Full Text Available ABSTRACT Objective To describe a unique operative strategy, instead the classical pterional approach, and to analyses it safety and effectiveness for removal of anterior cranial fossa meningiomas. Method We identify 38 patients with tuberculum sellae and olphactory groove meningiomas operated between 1986 and 2013. Medical charts, operative reports, imaging studies and clinical follow-up evaluations were reviewed and analyzed retrospectively. The pterional craniotomy is extended toward the frontal bone providing access through the subfrontal route, besides the usual anterolateral view provided by the classical pterional approach. Results Surgical mortality occurred in one patient (2.6%. Gross total resection was achieved in 27 patients (86.8%. Median time of follow-up was 69.4 months. Conclusion The extended pterional approach allows excellent results. Total removal of meningiomas of the anterior cranial fossa was obtained in 86.8 % of patients, with low morbidity and mortality.
Thermal-Chemical Model Of Subduction: Results And Tests
Gorczyk, W.; Gerya, T. V.; Connolly, J. A.; Yuen, D. A.; Rudolph, M.
2005-12-01
Seismic structures with strong positive and negative velocity anomalies in the mantle wedge above subduction zones have been interpreted as thermally and/or chemically induced phenomena. We have developed a thermal-chemical model of subduction, which constrains the dynamics of seismic velocity structure beneath volcanic arcs. Our simulations have been calculated over a finite-difference grid with (201×101) to (201×401) regularly spaced Eulerian points, using 0.5 million to 10 billion markers. The model couples numerical thermo-mechanical solution with Gibbs energy minimization to investigate the dynamic behavior of partially molten upwellings from slabs (cold plumes) and structures associated with their development. The model demonstrates two chemically distinct types of plumes (mixed and unmixed), and various rigid body rotation phenomena in the wedge (subduction wheel, fore-arc spin, wedge pin-ball). These thermal-chemical features strongly perturb seismic structure. Their occurrence is dependent on the age of subducting slab and the rate of subduction.The model has been validated through a series of test cases and its results are consistent with a variety of geological and geophysical data. In contrast to models that attribute a purely thermal origin for mantle wedge seismic anomalies, the thermal-chemical model is able to simulate the strong variations of seismic velocity existing beneath volcanic arcs which are associated with development of cold plumes. In particular, molten regions that form beneath volcanic arcs as a consequence of vigorous cold wet plumes are manifest by > 20% variations in the local Poisson ratio, as compared to variations of ~ 2% expected as a consequence of temperature variation within the mantle wedge.
Learning the Task Management Space of an Aircraft Approach Model
Krall, Joseph; Menzies, Tim; Davies, Misty
2014-01-01
Validating models of airspace operations is a particular challenge. These models are often aimed at finding and exploring safety violations, and aim to be accurate representations of real-world behavior. However, the rules governing the behavior are quite complex: nonlinear physics, operational modes, human behavior, and stochastic environmental concerns all determine the responses of the system. In this paper, we present a study on aircraft runway approaches as modeled in Georgia Tech's Work Models that Compute (WMC) simulation. We use a new learner, Genetic-Active Learning for Search-Based Software Engineering (GALE) to discover the Pareto frontiers defined by cognitive structures. These cognitive structures organize the prioritization and assignment of tasks of each pilot during approaches. We discuss the benefits of our approach, and also discuss future work necessary to enable uncertainty quantification.
Export of microplastics from land to sea. A modelling approach.
Siegfried, Max; Koelmans, Albert A; Besseling, Ellen; Kroeze, Carolien
2017-12-15
Quantifying the transport of plastic debris from river to sea is crucial for assessing the risks of plastic debris to human health and the environment. We present a global modelling approach to analyse the composition and quantity of point-source microplastic fluxes from European rivers to the sea. The model accounts for different types and sources of microplastics entering river systems via point sources. We combine information on these sources with information on sewage management and plastic retention during river transport for the largest European rivers. Sources of microplastics include personal care products, laundry, household dust and tyre and road wear particles (TRWP). Most of the modelled microplastics exported by rivers to seas are synthetic polymers from TRWP (42%) and plastic-based textiles abraded during laundry (29%). Smaller sources are synthetic polymers and plastic fibres in household dust (19%) and microbeads in personal care products (10%). Microplastic export differs largely among European rivers, as a result of differences in socio-economic development and technological status of sewage treatment facilities. About two-thirds of the microplastics modelled in this study flow into the Mediterranean and Black Sea. This can be explained by the relatively low microplastic removal efficiency of sewage treatment plants in the river basins draining into these two seas. Sewage treatment is generally more efficient in river basins draining into the North Sea, the Baltic Sea and the Atlantic Ocean. We use our model to explore future trends up to the year 2050. Our scenarios indicate that in the future river export of microplastics may increase in some river basins, but decrease in others. Remarkably, for many basins we calculate a reduction in river export of microplastics from point-sources, mainly due to an anticipated improvement in sewage treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.
PROSPECTS FOR TRANSPORT ENERGY CONSUMPTION: METHODOLOGICAL APPROACHES AND RESULTS OF FORECASTING
Directory of Open Access Journals (Sweden)
Eder L.V.
2016-03-01
specific energy consumption for both developed and developing countries for which there is a limited number of historical data. In order to improve the quality of forecasting specific number of vehicles, the authors of this article proposed to introduce additional parameters into the model, which would take into account differences in the countries of climatic, socio-economic, institutional conditions. As a result, it was identified five of the most significant factors affecting theratio of vehicles to population on basis of econometric analysis. The proposed methodological approach to determining the specific energy consumption of vehicle road transport and proposals for improving the methods of forecasting the number of vehicles it possible to predict energy demand of the transport sector in the long term.
Directory of Open Access Journals (Sweden)
Nemov V. Yu.
2016-03-01
specific energy consumption for both developed and developing countries for which there is a limited number of historical data. In order to improve the quality of forecasting specific number of vehicles, the authors of this article proposed to introduce additional parameters into the model, which would take into account differences in the countries of climatic, socio-economic, institutional conditions. As a result, it was identified five of the most significant factors affecting theratio of vehicles to population on basis of econometric analysis. The proposed methodological approach to determining the specific energy consumption of vehicle road transport and proposals for improving the methods of forecasting the number of vehicles it possible to predict energy demand of the transport sector in the long term.
Modeling Approaches and Systems Related to Structured Modeling.
1987-02-01
Lasdon > and Maturana > for surveys of several modern systems. A -6- N NN- %0 CAMPS (Lucas and Mitra >) -- Computer Assisted Mathe- %l...583-589. MATURANA , S. >. "Comparative Analysis of Mathematical Modeling Systems," informal note, Graduate School of Manage- ment, UCLA, February
An interdisciplinary approach to modeling tritium transfer into the environment
International Nuclear Information System (INIS)
Galeriu, D; Melintescu, A.
2005-01-01
More robust radiological assessment models are required to support the safety case for the nuclear industry. Heavy water reactors, fuel processing plants, radiopharmaceutical factories, and the future fusion reactor, all have large tritium loads. While of low probability, large accidental tritium releases cannot be ignored. For Romania that uses CANDU600 for nuclear energy, tritium is the national radionuclide. Tritium enters directly into the life cycle in many physicochemical forms. Tritiated water (HTO) is leaked from most nuclear installations but is partially converted into organically bound tritium (OBT) through plant and animal metabolic processes. Hydrogen and carbon are elemental components of major nutrients and animal tissues and their radioisotopes must be modeled differently from those of most other radionuclides. Tritium transfer from atmosphere to plant and conversion into organically bound tritium strongly depend on plant characteristics, season, and weather conditions. In order to cope with this large variability and avoid expensive calibration experiments, we developed a model using knowledge of plant physiology, agrometeorology, soil sciences, hydrology, and climatology. The transfer of tritiated water to plant was modeled with resistance approach including sparse canopy. The canopy resistance was modeled using the Jarvis-Calvet approach modified in order to make direct use of the canopy photosynthesis rate. The crop growth model WOFOST was used for photosynthesis rate both for canopy resistance and formation of organically bound tritium. Using this formalism, the tritium transfer parameters were directly linked to processes and parameters known from agricultural sciences. Model predictions for tritium in wheat were close to a factor two, according to experimental data without any calibration. The model was also tested on rice and soybean and can be applied for various plants and environmental conditions. For sparse canopy, the model used coupled
Modelling Approach to Assess Future Agricultural Water Demand
Spano, D.; Mancosu, N.; Orang, M.; Sarreshteh, S.; Snyder, R. L.
2013-12-01
The combination of long-term climate changes (e.g., warmer average temperatures) and extremes events (e.g., droughts) can have decisive impacts on water demand, with further implications on the ecosystems. In countries already affected by water scarcity, water management problems are becoming increasingly serious. The sustainable management of available water resources at the global, regional, and site-specific level is necessary. In agriculture, the first step is to compute how much water is needed by crops in regards to climate conditions. Modelling approach can be a way to compute crop water requirement (CWR). In this study, the improved version of the SIMETAW model was used. The model is a user friendly soil water balance model, developed by the University of California, Davis, the California Department of Water Resource, and the University of Sassari. The SIMETAW# model assesses CWR and generates hypothetical irrigation scheduling for a wide range of irrigated crops experiencing full, deficit, or no irrigation. The model computes the evapotranspiration of the applied water (ETaw), which is the sum of the net amount of irrigation water needed to match losses due to the crop evapotranspiration (ETc). ETaw is determined by first computing reference evapotranspiration (ETo) using the daily standardized Reference Evapotranspiration equation. ETaw is computed as ETaw = CETc - CEr, where CETc and CE are the cumulative total crop ET and effective rainfall values, respectively. Crop evapotranspiration is estimated as ETc = ETo x Kc, where Kc is the corrected midseason tabular crop coefficient, adjusted for climate conditions. The net irrigation amounts are determined from a daily soil water balance, using an integrated approach that considers soil and crop management information, and the daily ETc estimates. Using input information on irrigation system distribution uniformity and runoff, when appropriate, the model estimates the applied water to the low quarter of the
Stirling cryocooler test results and design model verification
International Nuclear Information System (INIS)
Shimko, M.A.; Stacy, W.D.; McCormick, J.A.
1990-01-01
This paper reports on progress in developing a long-life Stirling cycle cryocooler for space borne applications. It presents the results from tests on a preliminary breadboard version of the cryocooler used to demonstrate the feasibility of the technology and to validate the regenerator design code used in its development. This machine achieved a cold-end temperature of 65 K while carrying a 1/2 Watt cooling load. The basic machine is a double-acting, flexure-bearing, split Stirling design with linear electromagnetic drives for the expander and compressors. Flat metal diaphragms replace pistons for both sweeping and sealing the machine working volumes. In addition, the double-acting expander couples to a laminar-channel counterflow recuperative heat exchanger for regeneration. A PC compatible design code was developed for this design approach that calculates regenerator loss including heat transfer irreversibilities, pressure drop, and axial conduction in the regenerator walls
Measurement model choice influenced randomized controlled trial results.
Gorter, Rosalie; Fox, Jean-Paul; Apeldoorn, Adri; Twisk, Jos
2016-11-01
In randomized controlled trials (RCTs), outcome variables are often patient-reported outcomes measured with questionnaires. Ideally, all available item information is used for score construction, which requires an item response theory (IRT) measurement model. However, in practice, the classical test theory measurement model (sum scores) is mostly used, and differences between response patterns leading to the same sum score are ignored. The enhanced differentiation between scores with IRT enables more precise estimation of individual trajectories over time and group effects. The objective of this study was to show the advantages of using IRT scores instead of sum scores when analyzing RCTs. Two studies are presented, a real-life RCT, and a simulation study. Both IRT and sum scores are used to measure the construct and are subsequently used as outcomes for effect calculation. The bias in RCT results is conditional on the measurement model that was used to construct the scores. A bias in estimated trend of around one standard deviation was found when sum scores were used, where IRT showed negligible bias. Accurate statistical inferences are made from an RCT study when using IRT to estimate construct measurements. The use of sum scores leads to incorrect RCT results. Copyright Â© 2016 Elsevier Inc. All rights reserved.
Innovative Approaches to Assessment of Results of Higher School Students Training
Vaganova, Olga I.; Medvedeva, Tatiana Yu.; Kirdyanova, Elena R.; Kazantseva, Galina A.; Karpukova, Albina A.
2016-01-01
The basis of assessment tools selection for performance of control and evaluation of training results subject to requirements of modular-competence approach has been disclosed. The experience in implementation of assessment tools during "General and professional pedagogy" course has been observed. The objective of the study is rationale…
Soil moisture simulations using two different modelling approaches
Czech Academy of Sciences Publication Activity Database
Šípek, Václav; Tesař, Miroslav
2013-01-01
Roč. 64, 3-4 (2013), s. 99-103 ISSN 0006-5471 R&D Projects: GA AV ČR IAA300600901; GA ČR GA205/08/1174 Institutional research plan: CEZ:AV0Z20600510 Keywords : soil moisture modelling * SWIM model * box modelling approach Subject RIV: DA - Hydrology ; Limnology http://www.boku.ac.at/diebodenkultur/volltexte/sondernummern/band-64/heft-3-4/sipek.pdf
Model unspecific search in CMS. Results at 8 TeV
Energy Technology Data Exchange (ETDEWEB)
Albert, Andreas; Duchardt, Deborah; Hebbeker, Thomas; Knutzen, Simon; Lieb, Jonas; Meyer, Arnd; Pook, Tobias; Roemer, Jonas [III. Physikalisches Institut A, RWTH Aachen University (Germany)
2016-07-01
In the year 2012, CMS collected a total data set of approximately 20 fb{sup -1} in proton-proton collisions at √(s)=8 TeV. Dedicated searches for physics beyond the standard model are commonly designed with the signatures of a given theoretical model in mind. While this approach allows for an optimised sensitivity to the sought-after signal, it may cause unexpected phenomena to be overlooked. In a complementary approach, the Model Unspecific Search in CMS (MUSiC) analyses CMS data in a general way. Depending on the reconstructed final state objects (e.g. electrons), collision events are sorted into classes. In each of the classes, the distributions of selected kinematic variables are compared to standard model simulation. An automated statistical analysis is performed to quantify the agreement between data and prediction. In this talk, the analysis concept is introduced and selected results of the analysis of the 2012 CMS data set are presented.
A generic approach to haptic modeling of textile artifacts
Shidanshidi, H.; Naghdy, F.; Naghdy, G.; Wood Conroy, D.
2009-08-01
Haptic Modeling of textile has attracted significant interest over the last decade. In spite of extensive research, no generic system has been proposed. The previous work mainly assumes that textile has a 2D planar structure. They also require time-consuming measurement of textile properties in construction of the mechanical model. A novel approach for haptic modeling of textile is proposed to overcome the existing shortcomings. The method is generic, assumes a 3D structure for the textile, and deploys computational intelligence to estimate the mechanical properties of textile. The approach is designed primarily for display of textile artifacts in museums. The haptic model is constructed by superimposing the mechanical model of textile over its geometrical model. Digital image processing is applied to the still image of textile to identify its pattern and structure through a fuzzy rule-base algorithm. The 3D geometric model of the artifact is automatically generated in VRML based on the identified pattern and structure obtained from the textile image. Selected mechanical properties of the textile are estimated by an artificial neural network; deploying the textile geometric characteristics and yarn properties as inputs. The estimated mechanical properties are then deployed in the construction of the textile mechanical model. The proposed system is introduced and the developed algorithms are described. The validation of method indicates the feasibility of the approach and its superiority to other haptic modeling algorithms.
2009-11-01
Force Sustainability Modelling Tool Prototype GB Gigabyte GRES General Reserve HQ Headquarters HTA Hardening the Army JOLTS Joint Operational...Hardening the Army ( HTA ) proposed force structure.1 Following this work, the Director General Preparedness and Plans – Army (DGPP-A) approached DSTO to...that the different elements of the results for the corps have been identified, we can turn our attention to what the results say about the
Loss of spent fuel pool cooling PRA: Model and results
Energy Technology Data Exchange (ETDEWEB)
Siu, N.; Khericha, S.; Conroy, S.; Beck, S.; Blackman, H.
1996-09-01
This letter report documents models for quantifying the likelihood of loss of spent fuel pool cooling; models for identifying post-boiling scenarios that lead to core damage; qualitative and quantitative results generated for a selected plant that account for plant design and operational practices; a comparison of these results and those generated from earlier studies; and a review of available data on spent fuel pool accidents. The results of this study show that for a representative two-unit boiling water reactor, the annual probability of spent fuel pool boiling is 5 {times} 10{sup {minus}5} and the annual probability of flooding associated with loss of spent fuel pool cooling scenarios is 1 {times} 10{sup {minus}3}. Qualitative arguments are provided to show that the likelihood of core damage due to spent fuel pool boiling accidents is low for most US commercial nuclear power plants. It is also shown that, depending on the design characteristics of a given plant, the likelihood of either: (a) core damage due to spent fuel pool-associated flooding, or (b) spent fuel damage due to pool dryout, may not be negligible.
SR-Site groundwater flow modelling methodology, setup and results
Energy Technology Data Exchange (ETDEWEB)
Selroos, Jan-Olof (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Follin, Sven (SF GeoLogic AB, Taeby (Sweden))
2010-12-15
As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken three groundwater flow modelling studies. These are performed within the SR-Site project and represent time periods with different climate conditions. The simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. Three time periods are addressed; the Excavation and operational phases, the Initial period of temperate climate after closure, and the Remaining part of the reference glacial cycle. The present report is a synthesis of the background reports describing the modelling methodology, setup, and results. It is the primary reference for the conclusions drawn in a SR-Site specific context concerning groundwater flow during the three climate periods. These conclusions are not necessarily provided explicitly in the background reports, but are based on the results provided in these reports. The main results and comparisons presented in the present report are summarised in the SR-Site Main report.
Loss of spent fuel pool cooling PRA: Model and results
International Nuclear Information System (INIS)
Siu, N.; Khericha, S.; Conroy, S.; Beck, S.; Blackman, H.
1996-09-01
This letter report documents models for quantifying the likelihood of loss of spent fuel pool cooling; models for identifying post-boiling scenarios that lead to core damage; qualitative and quantitative results generated for a selected plant that account for plant design and operational practices; a comparison of these results and those generated from earlier studies; and a review of available data on spent fuel pool accidents. The results of this study show that for a representative two-unit boiling water reactor, the annual probability of spent fuel pool boiling is 5 x 10 -5 and the annual probability of flooding associated with loss of spent fuel pool cooling scenarios is 1 x 10 -3 . Qualitative arguments are provided to show that the likelihood of core damage due to spent fuel pool boiling accidents is low for most US commercial nuclear power plants. It is also shown that, depending on the design characteristics of a given plant, the likelihood of either: (a) core damage due to spent fuel pool-associated flooding, or (b) spent fuel damage due to pool dryout, may not be negligible
Energy Technology Data Exchange (ETDEWEB)
Engel, David W.; Reichardt, Thomas A.; Kulp, Thomas J.; Graff, David; Thompson, Sandra E.
2016-09-17
Validating predictive models and quantifying uncertainties inherent in the modeling process is a critical component of the HARD Solids Venture program [1]. Our current research focuses on validating physics-based models predicting the optical properties of solid materials for arbitrary surface morphologies and characterizing the uncertainties in these models. We employ a systematic and hierarchical approach by designing physical experiments and comparing the experimental results with the outputs of computational predictive models. We illustrate this approach through an example comparing a micro-scale forward model to an idealized solid-material system and then propagating the results through a system model to the sensor level. Our efforts should enhance detection reliability of the hyper-spectral imaging technique and the confidence in model utilization and model outputs by users and stakeholders.
Evaluation of the Split-H approach to modeling non-buoyant releases from vent stacks
International Nuclear Information System (INIS)
Ramsdell, J.V.
1983-04-01
Position C.2.b of Regulatory Guide 1.111 describes an approach to modeling the diffusion of effluents from roof top vents and short stacks using an elevated plume model under some conditions and using a ground-level source building wake model under other conditions. The approach is sometimes called a Split-H model. This report presents the results of an evaluation of the technical basis for and utility of the concept behind the Split-H model, outlines the devlopment of an upgraded model with those estimated using the Regulatory Guide Split-H model and a ground-level building wake model, and discusses alternatives to the Regulatory Guide position that the NRC may wish to consider. Concentration comparisons are made using model results for meteorological data from 18 nuclear power plant sites
Results of the benchmark for blade structural models, part A
DEFF Research Database (Denmark)
Lekou, D.J.; Chortis, D.; Belen Fariñas, A.
2013-01-01
Task 2.2 of the InnWind.Eu project. The benchmark is based on the reference wind turbine and the reference blade provided by DTU [1]. "Structural Concept developers/modelers" of WP2 were provided with the necessary input for a comparison numerical simulation run, upon definition of the reference blade......A benchmark on structural design methods for blades was performed within the InnWind.Eu project under WP2 “Lightweight Rotor” Task 2.2 “Lightweight structural design”. The present document is describes the results of the comparison simulation runs that were performed by the partners involved within...
Preliminary results of steel containment vessel model test
International Nuclear Information System (INIS)
Matsumoto, T.; Komine, K.; Arai, S.
1997-01-01
A high pressure test of a mixed-scaled model (1:10 in geometry and 1:4 in shell thickness) of a steel containment vessel (SCV), representing an improved boiling water reactor (BWR) Mark II containment, was conducted on December 11-12, 1996 at Sandia National Laboratories. This paper describes the preliminary results of the high pressure test. In addition, the preliminary post-test measurement data and the preliminary comparison of test data with pretest analysis predictions are also presented
An approach to model validation and model-based prediction -- polyurethane foam case study.
Energy Technology Data Exchange (ETDEWEB)
Dowding, Kevin J.; Rutherford, Brian Milne
2003-07-01
Enhanced software methodology and improved computing hardware have advanced the state of simulation technology to a point where large physics-based codes can be a major contributor in many systems analyses. This shift toward the use of computational methods has brought with it new research challenges in a number of areas including characterization of uncertainty, model validation, and the analysis of computer output. It is these challenges that have motivated the work described in this report. Approaches to and methods for model validation and (model-based) prediction have been developed recently in the engineering, mathematics and statistical literatures. In this report we have provided a fairly detailed account of one approach to model validation and prediction applied to an analysis investigating thermal decomposition of polyurethane foam. A model simulates the evolution of the foam in a high temperature environment as it transforms from a solid to a gas phase. The available modeling and experimental results serve as data for a case study focusing our model validation and prediction developmental efforts on this specific thermal application. We discuss several elements of the ''philosophy'' behind the validation and prediction approach: (1) We view the validation process as an activity applying to the use of a specific computational model for a specific application. We do acknowledge, however, that an important part of the overall development of a computational simulation initiative is the feedback provided to model developers and analysts associated with the application. (2) We utilize information obtained for the calibration of model parameters to estimate the parameters and quantify uncertainty in the estimates. We rely, however, on validation data (or data from similar analyses) to measure the variability that contributes to the uncertainty in predictions for specific systems or units (unit-to-unit variability). (3) We perform statistical
Using the mean approach in pooling cross-section and time series data for regression modelling
International Nuclear Information System (INIS)
Nuamah, N.N.N.N.
1989-12-01
The mean approach is one of the methods for pooling cross section and time series data for mathematical-statistical modelling. Though a simple approach, its results are sometimes paradoxical in nature. However, researchers still continue using it for its simplicity. Here, the paper investigates the nature and source of such unwanted phenomena. (author). 7 refs
Li, Zhichen; Bai, Yan; Huang, Congzhi; Yan, Huaicheng
2017-05-01
This paper investigates the stability and stabilization problems for interval time-delay systems. By introducing a new delay partitioning approach, various Lyapunov-Krasovskii functionals with triple-integral terms are established to make full use of system information. In order to reduce the conservatism, improved integral inequalities are developed for estimation of double integrals, which show remarkable outperformance over the Jensen and Wirtinger ones. Particularly, the relationship between the time-delay and each subinterval is taken into consideration. The resulting stability criteria are less conservative than some recent methods. Based on the derived condition, the state-feedback controller design approach is also given. Finally, the numerical examples and the application to inverted pendulum system are provided to illustrate the effectiveness of the proposed approaches. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.
A Neural Model of Face Recognition: a Comprehensive Approach
Stara, Vera; Montesanto, Anna; Puliti, Paolo; Tascini, Guido; Sechi, Cristina
Visual recognition of faces is an essential behavior of humans: we have optimal performance in everyday life and just such a performance makes us able to establish the continuity of actors in our social life and to quickly identify and categorize people. This remarkable ability justifies the general interest in face recognition of researchers belonging to different fields and specially of designers of biometrical identification systems able to recognize the features of person's faces in a background. Due to interdisciplinary nature of this topic in this contribute we deal with face recognition through a comprehensive approach with the purpose to reproduce some features of human performance, as evidenced by studies in psychophysics and neuroscience, relevant to face recognition. This approach views face recognition as an emergent phenomenon resulting from the nonlinear interaction of a number of different features. For this reason our model of face recognition has been based on a computational system implemented through an artificial neural network. This synergy between neuroscience and engineering efforts allowed us to implement a model that had a biological plausibility, performed the same tasks as human subjects, and gave a possible account of human face perception and recognition. In this regard the paper reports on an experimental study of performance of a SOM-based neural network in a face recognition task, with reference both to the ability to learn to discriminate different faces, and to the ability to recognize a face already encountered in training phase, when presented in a pose or with an expression differing from the one present in the training context.
A review of function modeling: Approaches and applications
Erden, M.S.; Komoto, H.; Van Beek, T.J.; D'Amelio, V.; Echavarria, E.; Tomiyama, T.
2008-01-01
This work is aimed at establishing a common frame and understanding of function modeling (FM) for our ongoing research activities. A comparative review of the literature is performed to grasp the various FM approaches with their commonalities and differences. The relations of FM with the research fields of artificial intelligence, design theory, and maintenance are discussed. In this discussion the goals are to highlight the features of various classical approaches in relation to FM, to delin...
Experimental Validation of Various Temperature Modells for Semi-Physical Tyre Model Approaches
Hackl, Andreas; Scherndl, Christoph; Hirschberg, Wolfgang; Lex, Cornelia
2017-10-01
With increasing level of complexity and automation in the area of automotive engineering, the simulation of safety relevant Advanced Driver Assistance Systems (ADAS) leads to increasing accuracy demands in the description of tyre contact forces. In recent years, with improvement in tyre simulation, the needs for coping with tyre temperatures and the resulting changes in tyre characteristics are rising significantly. Therefore, experimental validation of three different temperature model approaches is carried out, discussed and compared in the scope of this article. To investigate or rather evaluate the range of application of the presented approaches in combination with respect of further implementation in semi-physical tyre models, the main focus lies on the a physical parameterisation. Aside from good modelling accuracy, focus is held on computational time and complexity of the parameterisation process. To evaluate this process and discuss the results, measurements from a Hoosier racing tyre 6.0 / 18.0 10 LCO C2000 from an industrial flat test bench are used. Finally the simulation results are compared with the measurement data.
A model-data based systems approach to process intensification
DEFF Research Database (Denmark)
Gani, Rafiqul
. Their developments, however, are largely due to experiment based trial and error approaches and while they do not require validation, they can be time consuming and resource intensive. Also, one may ask, can a truly new intensified unit operation be obtained in this way? An alternative two-stage approach is to apply...... a model-based synthesis method to systematically generate and evaluate alternatives in the first stage and an experiment-model based validation in the second stage. In this way, the search for alternatives is done very quickly, reliably and systematically over a wide range, while resources are preserved...... for focused validation of only the promising candidates in the second-stage. This approach, however, would be limited to intensification based on “known” unit operations, unless the PI process synthesis/design is considered at a lower level of aggregation, namely the phenomena level. That is, the model-based...
Directory of Open Access Journals (Sweden)
Zaäfri Ananto Husodo
2015-04-01
Full Text Available This research proposes a numerical approach in estimating the trend of behavior of this market. This approach is applied to a model that is inspired by catalytic chemical model, in terms of differential equations, on four composite indices, New York Stock Exchange, Hong Kong Hang Seng, Straits Times Index, and Jakarta Stock Exchange, as suggested by Caetano and Yoneyama (2011. The approach is used to minimize the difference of estimated indices based on the model with respect to the actual data set. The result shows that the estimation is able to capture the trend of behavior in stock market well.
An algebraic approach to modeling in software engineering
International Nuclear Information System (INIS)
Loegel, C.J.; Ravishankar, C.V.
1993-09-01
Our work couples the formalism of universal algebras with the engineering techniques of mathematical modeling to develop a new approach to the software engineering process. Our purpose in using this combination is twofold. First, abstract data types and their specification using universal algebras can be considered a common point between the practical requirements of software engineering and the formal specification of software systems. Second, mathematical modeling principles provide us with a means for effectively analyzing real-world systems. We first use modeling techniques to analyze a system and then represent the analysis using universal algebras. The rest of the software engineering process exploits properties of universal algebras that preserve the structure of our original model. This paper describes our software engineering process and our experience using it on both research and commercial systems. We need a new approach because current software engineering practices often deliver software that is difficult to develop and maintain. Formal software engineering approaches use universal algebras to describe ''computer science'' objects like abstract data types, but in practice software errors are often caused because ''real-world'' objects are improperly modeled. There is a large semantic gap between the customer's objects and abstract data types. In contrast, mathematical modeling uses engineering techniques to construct valid models for real-world systems, but these models are often implemented in an ad hoc manner. A combination of the best features of both approaches would enable software engineering to formally specify and develop software systems that better model real systems. Software engineering, like mathematical modeling, should concern itself first and foremost with understanding a real system and its behavior under given circumstances, and then with expressing this knowledge in an executable form
Chen, Junjun
2018-03-30
Research into teacher emotion has attracted increasing attention in the last two decades. The relevance of teacher emotion in education has been highlighted. However, evidence of how teacher emotions impact their teaching approaches is rather limited. This study investigated the relationship between two self-report instruments - the Teacher Emotion Inventory and the Approach to Teaching. There were 1,830 teachers were approached from 43 primary schools in China and 12 primary schools in Hong Kong. Exploratory factor analysis, confirmatory factor analysis, and structural equation modelling were utilized in the analysis procedure. As a result, a five-factor TEI model was identified with two positive factors (Joy and Love) and three negative factors (Sadness, Anger, and Fear). A ATI model involved was confirmed with three factors (Knowledge Transmission, Student-Teacher Interaction, and Student Focus). Structural equation modelling demonstrated that more student-centred approaches are the consequence of positive teacher emotions while a teacher-centred approach is the consequence of negative teacher emotions although there are two surprising links. Identifying this pattern of relationships will contribute to understanding the reasons why new teaching strategies are often not adopted despite well-designed professional programs and educational reform and will provide implications for teaching improvement through teacher emotion. © 2018 The British Psychological Society.
Augustin, Jean-Christophe; Ferrier, Rachel; Hezard, Bernard; Lintz, Adrienne; Stahl, Valérie
2015-02-01
Individual-based modeling (IBM) approach combined with the microenvironment modeling of vacuum-packed cold-smoked salmon was more effective to describe the variability of the growth of a few Listeria monocytogenes cells contaminating irradiated salmon slices than the traditional population models. The IBM approach was particularly relevant to predict the absence of growth in 25% (5 among 20) of artificially contaminated cold-smoked salmon samples stored at 8 °C. These results confirmed similar observations obtained with smear soft cheese (Ferrier et al., 2013). These two different food models were used to compare the IBM/microscale and population/macroscale modeling approaches in more global exposure and risk assessment frameworks taking into account the variability and/or the uncertainty of the factors influencing the growth of L. monocytogenes. We observed that the traditional population models significantly overestimate exposure and risk estimates in comparison to IBM approach when contamination of foods occurs with a low number of cells (population model were characterized by a great uncertainty. The overestimation was mainly linked to the ability of IBM to predict no growth situations rather than the consideration of microscale environment. On the other hand, when the aim of quantitative risk assessment studies is only to assess the relative impact of changes in control measures affecting the growth of foodborne bacteria, the two modeling approach gave similar results and the simplest population approach was suitable. Copyright © 2014 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Rajib Kar
2010-03-01
Full Text Available On chip interconnect plays a dominant role on the circuit performance in both analog and digital domains. Interconnects can no longer be treated as mere delays or lumped RC networks. Crosstalk, ringing and reflections are just some of the issues that need to be addressed for the efficient design of high speed VLSI circuits. In order to accurately model these high frequency effects, inductance had been taken into consideration. Within this frequency range, the most accurate simulation model for on-chip VLSI interconnects was the distributed RLC model. Unfortunately, this model has many limitations at much higher of operating frequency used in today’s VLSI design. This can lead to inaccurate simulations if not modeled properly. At even higher frequency the conductance metrics has become a dominant factor and has to be taken into consideration for accurate modeling of the different on-chip performance parameters. The traditional analysis of crosstalk in a transmission line begins with a lossless LC representation, yielding a wave equation governing the system response. With the increase in frequency and interconnection length due to the increase in the number of on-chip devices, the lossy components are prevailing than the lossless components. With the reduction of pitch between the adjacent wires in deep sub-micron technologies, coupling capacitances are becoming significant. This increase in capacitances results the introduction of noise which is capable of propagating a logical fault. An inaccurate estimation of the crosstalk could be the origin of the malfunction of the circuit. Cross talk can be analyzed by computing the signal linkage between aggressor and victim nets. The aggressor net carries a signal that couples to the victim net through the parasitic capacitances [13]. To determine the effects that this cross talk will have on circuit operation, the resulting delays and logic levels for the victim nets must be computed. This paper
Directory of Open Access Journals (Sweden)
J. L. Chau
2008-08-01
Full Text Available In recent years, more and more radar systems with multiple-receiver antennas are being used to study the atmospheric and ionospheric irregularities with either interferometric and/or imaging configurations. In such systems, one of the major challenges is to know the phase offsets between the different receiver channels. Such phases are intrinsic to the system and are due to different cable lengths, filters, attenuators, amplifiers, antenna impedance, etc. Moreover, such phases change as function of time, on different time scales, depending on the specific installation. In this work, we present three approaches using natural targets (radio stars, meteor-head and meteor trail echoes that allow either an absolute or relative phase calibration. In addition, we present the results of using an artificial source (radio beacon for a continuous calibration that complements the previous approaches. These approaches are robust and good alternatives to other approaches, e.g. self-calibration techniques using known data features, or for multiple-receiver configurations constantly changing their receiving elements. In order to show the good performance of the proposed phase calibration techniques, we present new radar imaging results of equatorial spread F (ESF irregularities. Finally we introduce a new way to represent range-time intensity (RTI maps color coded with the Doppler information. Such modified map allows the identification and interpretation of geophysical phenomena, previously hidden in conventional RTI maps, e.g. the time and altitude of occurrence of ESF irregularities pinching off from the bottomside and their respective Doppler velocity.
Jordan, Pascal; Spiess, Martin
2017-10-13
In multidimensional item response models, paradoxical scoring effects can arise, wherein correct answers are penalized and incorrect answers are rewarded. For the most prominent class of IRT models, the class of linearly compensatory models, a general derivation of paradoxical scoring effects based on the geometry of item discrimination vectors is given, which furthermore corrects an error in an established theorem on paradoxical results. This approach highlights the very counterintuitive way in which item discrimination parameters (and also factor loadings) have to be interpreted in terms of their influence on the latent ability estimate. It is proven that, despite the error in the original proof, the key result concerning the existence of paradoxical effects remains true-although the actual relation to the item parameters is shown to be a more complicated function than previous results suggested. The new proof enables further insights into the actual mathematical causation of the paradox and generalizes the findings within the class of linearly compensatory models.
Computational Approaches for Modeling the Multiphysics in Pultrusion Process
Directory of Open Access Journals (Sweden)
P. Carlone
2013-01-01
Full Text Available Pultrusion is a continuous manufacturing process used to produce high strength composite profiles with constant cross section. The mutual interactions between heat transfer, resin flow and cure reaction, variation in the material properties, and stress/distortion evolutions strongly affect the process dynamics together with the mechanical properties and the geometrical precision of the final product. In the present work, pultrusion process simulations are performed for a unidirectional (UD graphite/epoxy composite rod including several processing physics, such as fluid flow, heat transfer, chemical reaction, and solid mechanics. The pressure increase and the resin flow at the tapered inlet of the die are calculated by means of a computational fluid dynamics (CFD finite volume model. Several models, based on different homogenization levels and solution schemes, are proposed and compared for the evaluation of the temperature and the degree of cure distributions inside the heating die and at the postdie region. The transient stresses, distortions, and pull force are predicted using a sequentially coupled three-dimensional (3D thermochemical analysis together with a 2D plane strain mechanical analysis using the finite element method and compared with results obtained from a semianalytical approach.
Forecasting wind-driven wildfires using an inverse modelling approach
Directory of Open Access Journals (Sweden)
O. Rios
2014-06-01
Full Text Available A technology able to rapidly forecast wildfire dynamics would lead to a paradigm shift in the response to emergencies, providing the Fire Service with essential information about the ongoing fire. This paper presents and explores a novel methodology to forecast wildfire dynamics in wind-driven conditions, using real-time data assimilation and inverse modelling. The forecasting algorithm combines Rothermel's rate of spread theory with a perimeter expansion model based on Huygens principle and solves the optimisation problem with a tangent linear approach and forward automatic differentiation. Its potential is investigated using synthetic data and evaluated in different wildfire scenarios. The results show the capacity of the method to quickly predict the location of the fire front with a positive lead time (ahead of the event in the order of 10 min for a spatial scale of 100 m. The greatest strengths of our method are lightness, speed and flexibility. We specifically tailor the forecast to be efficient and computationally cheap so it can be used in mobile systems for field deployment and operativeness. Thus, we put emphasis on producing a positive lead time and the means to maximise it.
Do recommender systems benefit users? a modeling approach
Yeung, Chi Ho
2016-04-01
Recommender systems are present in many web applications to guide purchase choices. They increase sales and benefit sellers, but whether they benefit customers by providing relevant products remains less explored. While in many cases the recommended products are relevant to users, in other cases customers may be tempted to purchase the products only because they are recommended. Here we introduce a model to examine the benefit of recommender systems for users, and find that recommendations from the system can be equivalent to random draws if one always follows the recommendations and seldom purchases according to his or her own preference. Nevertheless, with sufficient information about user preferences, recommendations become accurate and an abrupt transition to this accurate regime is observed for some of the studied algorithms. On the other hand, we find that high estimated accuracy indicated by common accuracy metrics is not necessarily equivalent to high real accuracy in matching users with products. This disagreement between estimated and real accuracy serves as an alarm for operators and researchers who evaluate recommender systems merely with accuracy metrics. We tested our model with a real dataset and observed similar behaviors. Finally, a recommendation approach with improved accuracy is suggested. These results imply that recommender systems can benefit users, but the more frequently a user purchases the recommended products, the less relevant the recommended products are in matching user taste.
Injury prevention risk communication: A mental models approach
DEFF Research Database (Denmark)
Austin, Laurel Cecelia; Fischhoff, Baruch
2012-01-01
Individuals' decisions and behaviour can play a critical role in determining both the probability and severity of injury. Behavioural decision research studies peoples' decision-making processes in terms comparable to scientific models of optimal choices, providing a basis for focusing...... interventions on the most critical opportunities to reduce risks. That research often seeks to identify the ‘mental models’ that underlie individuals' interpretations of their circumstances and the outcomes of possible actions. In the context of injury prevention, a mental models approach would ask why people...... and uses examples to discuss how the approach can be used to develop scientifically validated context-sensitive injury risk communications....
Chiadamrong, N.; Piyathanavong, V.
2017-12-01
Models that aim to optimize the design of supply chain networks have gained more interest in the supply chain literature. Mixed-integer linear programming and discrete-event simulation are widely used for such an optimization problem. We present a hybrid approach to support decisions for supply chain network design using a combination of analytical and discrete-event simulation models. The proposed approach is based on iterative procedures until the difference between subsequent solutions satisfies the pre-determined termination criteria. The effectiveness of proposed approach is illustrated by an example, which shows closer to optimal results with much faster solving time than the results obtained from the conventional simulation-based optimization model. The efficacy of this proposed hybrid approach is promising and can be applied as a powerful tool in designing a real supply chain network. It also provides the possibility to model and solve more realistic problems, which incorporate dynamism and uncertainty.
Agent-based modeling: a new approach for theory building in social psychology.
Smith, Eliot R; Conrey, Frederica R
2007-02-01
Most social and psychological phenomena occur not as the result of isolated decisions by individuals but rather as the result of repeated interactions between multiple individuals over time. Yet the theory-building and modeling techniques most commonly used in social psychology are less than ideal for understanding such dynamic and interactive processes. This article describes an alternative approach to theory building, agent-based modeling (ABM), which involves simulation of large numbers of autonomous agents that interact with each other and with a simulated environment and the observation of emergent patterns from their interactions. The authors believe that the ABM approach is better able than prevailing approaches in the field, variable-based modeling (VBM) techniques such as causal modeling, to capture types of complex, dynamic, interactive processes so important in the social world. The article elaborates several important contrasts between ABM and VBM and offers specific recommendations for learning more and applying the ABM approach.
Hamiltonian Approach to QCD in Coulomb Gauge: A Survey of Recent Results
Directory of Open Access Journals (Sweden)
H. Reinhardt
2018-01-01
Full Text Available We report on recent results obtained within the Hamiltonian approach to QCD in Coulomb gauge. Furthermore this approach is compared to recent lattice data, which were obtained by an alternative gauge-fixing method and which show an improved agreement with the continuum results. By relating the Gribov confinement scenario to the center vortex picture of confinement, it is shown that the Coulomb string tension is tied to the spatial string tension. For the quark sector, a vacuum wave functional is used which explicitly contains the coupling of the quarks to the transverse gluons and which results in variational equations which are free of ultraviolet divergences. The variational approach is extended to finite temperatures by compactifying a spatial dimension. The effective potential of the Polyakov loop is evaluated from the zero-temperature variational solution. For pure Yang–Mills theory, the deconfinement phase transition is found to be second order for SU(2 and first order for SU(3, in agreement with the lattice results. The corresponding critical temperatures are found to be 275 MeV and 280 MeV, respectively. When quarks are included, the deconfinement transition turns into a crossover. From the dual and chiral quark condensate, one finds pseudocritical temperatures of 198 MeV and 170 MeV, respectively, for the deconfinement and chiral transition.
Mathematical and computer modeling of electro-optic systems using a generic modeling approach
Smith, M.I.; Murray-Smith, D.J.; Hickman, D.
2007-01-01
The conventional approach to modelling electro-optic sensor systems is to develop separate models for individual systems or classes of system, depending on the detector technology employed in the sensor and the application. However, this ignores commonality in design and in components of these systems. A generic approach is presented for modelling a variety of sensor systems operating in the infrared waveband that also allows systems to be modelled with different levels of detail and at diffe...
Deep Appearance Models: A Deep Boltzmann Machine Approach for Face Modeling
Duong, Chi Nhan; Luu, Khoa; Quach, Kha Gia; Bui, Tien D.
2016-01-01
The "interpretation through synthesis" approach to analyze face images, particularly Active Appearance Models (AAMs) method, has become one of the most successful face modeling approaches over the last two decades. AAM models have ability to represent face images through synthesis using a controllable parameterized Principal Component Analysis (PCA) model. However, the accuracy and robustness of the synthesized faces of AAM are highly depended on the training sets and inherently on the genera...
Bianchi VI0 and III models: self-similar approach
International Nuclear Information System (INIS)
Belinchon, Jose Antonio
2009-01-01
We study several cosmological models with Bianchi VI 0 and III symmetries under the self-similar approach. We find new solutions for the 'classical' perfect fluid model as well as for the vacuum model although they are really restrictive for the equation of state. We also study a perfect fluid model with time-varying constants, G and Λ. As in other studied models we find that the behaviour of G and Λ are related. If G behaves as a growing time function then Λ is a positive decreasing time function but if G is decreasing then Λ 0 is negative. We end by studying a massive cosmic string model, putting special emphasis in calculating the numerical values of the equations of state. We show that there is no SS solution for a string model with time-varying constants.
Modeling and control approach to a distinctive quadrotor helicopter.
Wu, Jun; Peng, Hui; Chen, Qing; Peng, Xiaoyan
2014-01-01
The referenced quadrotor helicopter in this paper has a unique configuration. It is more complex than commonly used quadrotors because of its inaccurate parameters, unideal symmetrical structure and unknown nonlinear dynamics. A novel method was presented to handle its modeling and control problems in this paper, which adopts a MIMO RBF neural nets-based state-dependent ARX (RBF-ARX) model to represent its nonlinear dynamics, and then a MIMO RBF-ARX model-based global LQR controller is proposed to stabilize the quadrotor's attitude. By comparing with a physical model-based LQR controller and an ARX model-set-based gain scheduling LQR controller, superiority of the MIMO RBF-ARX model-based control approach was confirmed. This successful application verified the validity of the MIMO RBF-ARX modeling method to the quadrotor helicopter with complex nonlinearity. © 2013 Published by ISA. All rights reserved.
Software sensors based on the grey-box modelling approach
DEFF Research Database (Denmark)
Carstensen, J.; Harremoës, P.; Strube, Rune
1996-01-01
In recent years the grey-box modelling approach has been applied to wastewater transportation and treatment Grey-box models are characterized by the combination of deterministic and stochastic terms to form a model where all the parameters are statistically identifiable from the on......-line measurements. With respect to the development of software sensors, the grey-box models possess two important features. Firstly, the on-line measurements can be filtered according to the grey-box model in order to remove noise deriving from the measuring equipment and controlling devices. Secondly, the grey......-box models may contain terms which can be estimated on-line by use of the models and measurements. In this paper, it is demonstrated that many storage basins in sewer systems can be used as an on-line flow measurement provided that the basin is monitored on-line with a level transmitter and that a grey...
Environmental Radiation Effects on Mammals A Dynamical Modeling Approach
Smirnova, Olga A
2010-01-01
This text is devoted to the theoretical studies of radiation effects on mammals. It uses the framework of developed deterministic mathematical models to investigate the effects of both acute and chronic irradiation in a wide range of doses and dose rates on vital body systems including hematopoiesis, small intestine and humoral immunity, as well as on the development of autoimmune diseases. Thus, these models can contribute to the development of the system and quantitative approaches in radiation biology and ecology. This text is also of practical use. Its modeling studies of the dynamics of granulocytopoiesis and thrombocytopoiesis in humans testify to the efficiency of employment of the developed models in the investigation and prediction of radiation effects on these hematopoietic lines. These models, as well as the properly identified models of other vital body systems, could provide a better understanding of the radiation risks to health. The modeling predictions will enable the implementation of more ef...
MSFC Stream Model Preliminary Results: Modeling Recent Leonid and Perseid Encounters
Cooke, William J.; Moser, Danielle E.
2004-01-01
The cometary meteoroid ejection model of Jones and Brown (1996b) was used to simulate ejection from comets 55P/Tempel-Tuttle during the last 12 revolutions, and the last 9 apparitions of 109P/Swift-Tuttle. Using cometary ephemerides generated by the Jet Propulsion Laboratory s (JPL) HORIZONS Solar System Data and Ephemeris Computation Service, two independent ejection schemes were simulated. In the first case, ejection was simulated in 1 hour time steps along the comet s orbit while it was within 2.5 AU of the Sun. In the second case, ejection was simulated to occur at the hour the comet reached perihelion. A 4th order variable step-size Runge-Kutta integrator was then used to integrate meteoroid position and velocity forward in time, accounting for the effects of radiation pressure, Poynting-Robertson drag, and the gravitational forces of the planets, which were computed using JPL s DE406 planetary ephemerides. An impact parameter was computed for each particle approaching the Earth to create a flux profile, and the results compared to observations of the 1998 and 1999 Leonid showers, and the 1993 and 2004 Perseids.
A new approach to BRST operator cohomologies: Exact results for the BRST-Fock theories
International Nuclear Information System (INIS)
Horuzhy, S.S.; Voronin, A.V.
1993-01-01
The modification of the BRST approach suggested by the authors and based on using the Lie superalgebra l(1, 1) as the full algebra of the BRST symmetry is applied to the problem of calculating BRST operator cohomologies. The calculation is done for the class of BRST-Fock theories. The operator cohomologies are proved to be trivial. The result is interpreted as the analog of the no-ghost theorem on the level of observables. 7 refs
Directory of Open Access Journals (Sweden)
Tomas Drgon
Full Text Available BACKGROUND: Vulnerabilities to dependence on addictive substances are substantially heritable complex disorders whose underlying genetic architecture is likely to be polygenic, with modest contributions from variants in many individual genes. "Nontemplate" genome wide association (GWA approaches can identity groups of chromosomal regions and genes that, taken together, are much more likely to contain allelic variants that alter vulnerability to substance dependence than expected by chance. METHODOLOGY/PRINCIPAL FINDINGS: We report pooled "nontemplate" genome-wide association studies of two independent samples of substance dependent vs control research volunteers (n = 1620, one European-American and the other African-American using 1 million SNP (single nucleotide polymorphism Affymetrix genotyping arrays. We assess convergence between results from these two samples using two related methods that seek clustering of nominally-positive results and assess significance levels with Monte Carlo and permutation approaches. Both "converge then cluster" and "cluster then converge" analyses document convergence between the results obtained from these two independent datasets in ways that are virtually never found by chance. The genes identified in this fashion are also identified by individually-genotyped dbGAP data that compare allele frequencies in cocaine dependent vs control individuals. CONCLUSIONS/SIGNIFICANCE: These overlapping results identify small chromosomal regions that are also identified by genome wide data from studies of other relevant samples to extents much greater than chance. These chromosomal regions contain more genes related to "cell adhesion" processes than expected by chance. They also contain a number of genes that encode potential targets for anti-addiction pharmacotherapeutics. "Nontemplate" GWA approaches that seek chromosomal regions in which nominally-positive associations are found in multiple independent samples are likely
Position-sensitive transition edge sensor modeling and results
Energy Technology Data Exchange (ETDEWEB)
Hammock, Christina E-mail: chammock@milkyway.gsfc.nasa.gov; Figueroa-Feliciano, Enectali; Apodaca, Emmanuel; Bandler, Simon; Boyce, Kevin; Chervenak, Jay; Finkbeiner, Fred; Kelley, Richard; Lindeman, Mark; Porter, Scott; Saab, Tarek; Stahle, Caroline
2004-03-11
We report the latest design and experimental results for a Position-Sensitive Transition-Edge Sensor (PoST). The PoST is motivated by the desire to achieve a larger field-of-view without increasing the number of readout channels. A PoST consists of a one-dimensional array of X-ray absorbers connected on each end to a Transition Edge Sensor (TES). Position differentiation is achieved through a comparison of pulses between the two TESs and X-ray energy is inferred from a sum of the two signals. Optimizing such a device involves studying the available parameter space which includes device properties such as heat capacity and thermal conductivity as well as TES read-out circuitry parameters. We present results for different regimes of operation and the effects on energy resolution, throughput, and position differentiation. Results and implications from a non-linear model developed to study the saturation effects unique to PoSTs are also presented.
Comparison of blade-strike modeling results with empirical data
Energy Technology Data Exchange (ETDEWEB)
Ploskey, Gene R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, Thomas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2004-03-01
This study is the initial stage of further investigation into the dynamics of injury to fish during passage through a turbine runner. As part of the study, Pacific Northwest National Laboratory (PNNL) estimated the probability of blade strike, and associated injury, as a function of fish length and turbine operating geometry at two adjacent turbines in Powerhouse 1 of Bonneville Dam. Units 5 and 6 had identical intakes, stay vanes, wicket gates, and draft tubes, but Unit 6 had a new runner and curved discharge ring to minimize gaps between the runner hub and blades and between the blade tips and discharge ring. We used a mathematical model to predict blade strike associated with two Kaplan turbines and compared results with empirical data from biological tests conducted in 1999 and 2000. Blade-strike models take into consideration the geometry of the turbine blades and discharges as well as fish length, orientation, and distribution along the runner. The first phase of this study included a sensitivity analysis to consider the effects of difference in geometry and operations between families of turbines on the strike probability response surface. The analysis revealed that the orientation of fish relative to the leading edge of a runner blade and the location that fish pass along the blade between the hub and blade tip are critical uncertainties in blade-strike models. Over a range of discharges, the average prediction of injury from blade strike was two to five times higher than average empirical estimates of visible injury from shear and mechanical devices. Empirical estimates of mortality may be better metrics for comparison to predicted injury rates than other injury measures for fish passing at mid-blade and blade-tip locations.
Brito, David; Campuzano, F. J.; Sobrinho, J.; Fernandes, R.; Neves, R.
2015-12-01
River discharges and loads are essential inputs to coastal seas, and thus for coastal seas modelling, and their properties are the result of all activities and policies carried inland. For these reasons main rivers were object of intense monitoring programs having been generated some important amount of historical data. Due to the decline in the Portuguese hydrometric network and in order to quantify and forecast surface water streamflow and nutrients to coastal areas, the MOHID Land model was applied to the Western Iberia Region with a 2 km horizontal resolution and to the Iberian Peninsula with 10 km horizontal resolution. The domains were populated with land use and soil properties and forced with existing meteorological models. This approach also permits to understand how the flows and loads are generated and to forecast their values which are of utmost importance to perform coastal ocean and estuarine forecasts. The final purpose of the implementation is to obtain fresh water quantity and quality that could be used to support management decisions in the watershed, reservoirs and also to estuaries and coastal areas. A process oriented model as MOHID Land is essential to perform this type of simulations, as the model is independent of the number of river catchments. In this work, the Mohid Land model equations and parameterisations were described and an innovative methodology for watershed modelling is presented and validated for a large international river, the Tagus River, and the largest national river of Portugal, the Mondego River. Precipitation, streamflow and nutrients modelling results for these two rivers were compared with observations near their coastal outlet in order to evaluate the model capacity to represent the main watershed trends. Finally, an annual budget of fresh water and nutrient transported by the main twenty five rivers discharging in the Portuguese coast is presented.
Kuroishi, Y.; Lemoine, F. G.; Rowlands, D. D.
2006-12-01
The latest gravimetric geoid model for Japan, JGEOID2004, suffers from errors at long wavelengths (around 1000 km) in a range of +/- 30 cm. The model was developed by combining surface gravity data with a global marine altimetric gravity model, using EGM96 as a foundation, and the errors at long wavelength are presumably attributed to EGM96 errors. The Japanese islands and their vicinity are located in a region of plate convergence boundaries, producing substantial gravity and geoid undulations in a wide range of wavelengths. Because of the geometry of the islands and trenches, precise information on gravity in the surrounding oceans should be incorporated in detail, even if the geoid model is required to be accurate only over land. The Kuroshio Current, which runs south of Japan, causes high sea surface variability, making altimetric gravity field determination complicated. To reduce the long-wavelength errors in the geoid model, we are investigating GRACE data for regional gravity field modeling at long wavelengths in the vicinity of Japan. Our approach is based on exclusive use of inter- satellite range-rate data with calibrated accelerometer data and attitude data, for regional or global gravity field recovery. In the first step, we calibrate accelerometer data in terms of scales and biases by fitting dynamically calculated orbits to GPS-determined precise orbits. The calibration parameters of accelerometer data thus obtained are used in the second step to recover a global/regional gravity anomaly field. This approach is applied to GRACE data obtained for the year 2005 and resulting global/regional gravity models are presented and discussed.
Modelling dynamic ecosystems : venturing beyond boundaries with the Ecopath approach
Coll, Marta; Akoglu, E.; Arreguin-Sanchez, F.; Fulton, E. A.; Gascuel, D.; Heymans, J. J.; Libralato, S.; Mackinson, S.; Palomera, I.; Piroddi, C.; Shannon, L. J.; Steenbeek, J.; Villasante, S.; Christensen, V.
2015-01-01
Thirty years of progress using the Ecopath with Ecosim (EwE) approach in different fields such as ecosystem impacts of fishing and climate change, emergent ecosystem dynamics, ecosystem-based management, and marine conservation and spatial planning were showcased November 2014 at the conference "Ecopath 30 years-modelling dynamic ecosystems: beyond boundaries with EwE". Exciting new developments include temporal-spatial and end-to-end modelling, as well as novel applications to environmental ...
Regularization of quantum gravity in the matrix model approach
International Nuclear Information System (INIS)
Ueda, Haruhiko
1991-02-01
We study divergence problem of the partition function in the matrix model approach for two-dimensional quantum gravity. We propose a new model V(φ) = 1/2Trφ 2 + g 4 /NTrφ 4 + g'/N 4 Tr(φ 4 ) 2 and show that in the sphere case it has no divergence problem and the critical exponent is of pure gravity. (author)
Gray-box modelling approach for description of storage tunnel
DEFF Research Database (Denmark)
Harremoës, Poul; Carstensen, Jacob
1999-01-01
The dynamics of a storage tunnel is examined using a model based on on-line measured data and a combination of simple deterministic and black-box stochastic elements. This approach, called gray-box modeling, is a new promising methodology for giving an on-line state description of sewer systems. ...... in a SCADA system because the most important information on the specific system is provided on-line...
Development of a Conservative Model Validation Approach for Reliable Analysis
2015-01-01
conservativeness level , the conservative probability of failure obtained from Section 4 must be maintained. The mathematical formulation of conservative model... CIE 2015 August 2-5, 2015, Boston, Massachusetts, USA [DRAFT] DETC2015-46982 DEVELOPMENT OF A CONSERVATIVE MODEL VALIDATION APPROACH FOR RELIABLE...PDF and a probability of failure are selected from these predicted output PDFs at a user-specified conservativeness level for validation. For
A developmental approach to learning causal models for cyber security
Mugan, Jonathan
2013-05-01
To keep pace with our adversaries, we must expand the scope of machine learning and reasoning to address the breadth of possible attacks. One approach is to employ an algorithm to learn a set of causal models that describes the entire cyber network and each host end node. Such a learning algorithm would run continuously on the system and monitor activity in real time. With a set of causal models, the algorithm could anticipate novel attacks, take actions to thwart them, and predict the second-order effects flood of information, and the algorithm would have to determine which streams of that flood were relevant in which situations. This paper will present the results of efforts toward the application of a developmental learning algorithm to the problem of cyber security. The algorithm is modeled on the principles of human developmental learning and is designed to allow an agent to learn about the computer system in which it resides through active exploration. Children are flexible learners who acquire knowledge by actively exploring their environment and making predictions about what they will find,1, 2 and our algorithm is inspired by the work of the developmental psychologist Jean Piaget.3 Piaget described how children construct knowledge in stages and learn new concepts on top of those they already know. Developmental learning allows our algorithm to focus on subsets of the environment that are most helpful for learning given its current knowledge. In experiments, the algorithm was able to learn the conditions for file exfiltration and use that knowledge to protect sensitive files.
Valle, Denis; Lima, Joanna M Tucker; Millar, Justin; Amratia, Punam; Haque, Ubydul
2015-11-04
Logistic regression is a statistical model widely used in cross-sectional and cohort studies to identify and quantify the effects of potential disease risk factors. However, the impact of imperfect tests on adjusted odds ratios (and thus on the identification of risk factors) is under-appreciated. The purpose of this article is to draw attention to the problem associated with modelling imperfect diagnostic tests, and propose simple Bayesian models to adequately address this issue. A systematic literature review was conducted to determine the proportion of malaria studies that appropriately accounted for false-negatives/false-positives in a logistic regression setting. Inference from the standard logistic regression was also compared with that from three proposed Bayesian models using simulations and malaria data from the western Brazilian Amazon. A systematic literature review suggests that malaria epidemiologists are largely unaware of the problem of using logistic regression to model imperfect diagnostic test results. Simulation results reveal that statistical inference can be substantially improved when using the proposed Bayesian models versus the standard logistic regression. Finally, analysis of original malaria data with one of the proposed Bayesian models reveals that microscopy sensitivity is strongly influenced by how long people have lived in the study region, and an important risk factor (i.e., participation in forest extractivism) is identified that would have been missed by standard logistic regression. Given the numerous diagnostic methods employed by malaria researchers and the ubiquitous use of logistic regression to model the results of these diagnostic tests, this paper provides critical guidelines to improve data analysis practice in the presence of misclassification error. Easy-to-use code that can be readily adapted to WinBUGS is provided, enabling straightforward implementation of the proposed Bayesian models.
Macho, Siegfried; Ledermann, Thomas
2011-01-01
The phantom model approach for estimating, testing, and comparing specific effects within structural equation models (SEMs) is presented. The rationale underlying this novel method consists in representing the specific effect to be assessed as a total effect within a separate latent variable model, the phantom model that is added to the main…
A Final Approach Trajectory Model for Current Operations
Gong, Chester; Sadovsky, Alexander
2010-01-01
Predicting accurate trajectories with limited intent information is a challenge faced by air traffic management decision support tools in operation today. One such tool is the FAA's Terminal Proximity Alert system which is intended to assist controllers in maintaining safe separation of arrival aircraft during final approach. In an effort to improve the performance of such tools, two final approach trajectory models are proposed; one based on polynomial interpolation, the other on the Fourier transform. These models were tested against actual traffic data and used to study effects of the key final approach trajectory modeling parameters of wind, aircraft type, and weight class, on trajectory prediction accuracy. Using only the limited intent data available to today's ATM system, both the polynomial interpolation and Fourier transform models showed improved trajectory prediction accuracy over a baseline dead reckoning model. Analysis of actual arrival traffic showed that this improved trajectory prediction accuracy leads to improved inter-arrival separation prediction accuracy for longer look ahead times. The difference in mean inter-arrival separation prediction error between the Fourier transform and dead reckoning models was 0.2 nmi for a look ahead time of 120 sec, a 33 percent improvement, with a corresponding 32 percent improvement in standard deviation.
Modeling of phase equilibria with CPA using the homomorph approach
DEFF Research Database (Denmark)
Breil, Martin Peter; Tsivintzelis, Ioannis; Kontogeorgis, Georgios
2011-01-01
For association models, like CPA and SAFT, a classical approach is often used for estimating pure-compound and mixture parameters. According to this approach, the pure-compound parameters are estimated from vapor pressure and liquid density data. Then, the binary interaction parameters, kij......, are estimated from binary systems; one binary interaction parameter per system. No additional mixing rules are needed for cross-associating systems, but combining rules are required, e.g. the Elliott rule or the so-called CR-1 rule. There is a very large class of mixtures, e.g. water or glycols with aromatic...... interaction parameters are often used for solvating systems; one for the physical part (kij) and one for the association part (βcross). This limits the predictive capabilities and possibilities of generalization of the model. In this work we present an approach to reduce the number of adjustable parameters...
A model-data based systems approach to process intensification
DEFF Research Database (Denmark)
Gani, Rafiqul
. Their developments, however, are largely due to experiment based trial and error approaches and while they do not require validation, they can be time consuming and resource intensive. Also, one may ask, can a truly new intensified unit operation be obtained in this way? An alternative two-stage approach is to apply...... for focused validation of only the promising candidates in the second-stage. This approach, however, would be limited to intensification based on “known” unit operations, unless the PI process synthesis/design is considered at a lower level of aggregation, namely the phenomena level. That is, the model......-based synthesis method must employ models at lower levels of aggregation and through combination rules for phenomena, generate (synthesize) new intensified unit operations. An efficient solution procedure for the synthesis problem is needed to tackle the potentially large number of options that would be obtained...
A review of function modeling : Approaches and applications
Erden, M.S.; Komoto, H.; Van Beek, T.J.; D'Amelio, V.; Echavarria, E.; Tomiyama, T.
2008-01-01
This work is aimed at establishing a common frame and understanding of function modeling (FM) for our ongoing research activities. A comparative review of the literature is performed to grasp the various FM approaches with their commonalities and differences. The relations of FM with the research
The Bipolar Approach: A Model for Interdisciplinary Art History Courses.
Calabrese, John A.
1993-01-01
Describes a college level art history course based on the opposing concepts of Classicism and Romanticism. Contends that all creative work, such as film or architecture, can be categorized according to this bipolar model. Includes suggestions for objects to study and recommends this approach for art education at all education levels. (CFR)
Model-independent approach for dark matter phenomenology ...
Indian Academy of Sciences (India)
We have studied the phenomenology of dark matter at the ILC and cosmic positron experiments based on model-independent approach. We have found a strong correlation between dark matter signatures at the ILC and those in the indirect detection experiments of dark matter. Once the dark matter is discovered in the ...
A Behavioral Decision Making Modeling Approach Towards Hedging Services
Pennings, J.M.E.; Candel, M.J.J.M.; Egelkraut, T.M.
2003-01-01
This paper takes a behavioral approach toward the market for hedging services. A behavioral decision-making model is developed that provides insight into how and why owner-managers decide the way they do regarding hedging services. Insight into those choice processes reveals information needed by
Comparing State SAT Scores Using a Mixture Modeling Approach
Kim, YoungKoung Rachel
2009-01-01
Presented at the national conference for AERA (American Educational Research Association) in April 2009. The large variability of SAT taker population across states makes state-by-state comparisons of the SAT scores challenging. Using a mixture modeling approach, therefore, the current study presents a method of identifying subpopulations in terms…
Export of microplastics from land to sea. A modelling approach
Siegfried, Max; Koelmans, A.A.; Besseling, E.; Kroeze, C.
2017-01-01
Quantifying the transport of plastic debris from river to sea is crucial for assessing the risks of plastic debris to human health and the environment. We present a global modelling approach to analyse the composition and quantity of point-source microplastic fluxes from European rivers to the sea.
A novel Monte Carlo approach to hybrid local volatility models
A.W. van der Stoep (Anton); L.A. Grzelak (Lech Aleksander); C.W. Oosterlee (Cornelis)
2017-01-01
textabstractWe present in a Monte Carlo simulation framework, a novel approach for the evaluation of hybrid local volatility [Risk, 1994, 7, 18–20], [Int. J. Theor. Appl. Finance, 1998, 1, 61–110] models. In particular, we consider the stochastic local volatility model—see e.g. Lipton et al. [Quant.
Hidden Markov model-based approach for generation of Pitman ...
Indian Academy of Sciences (India)
Speech is one of the most basic means of human communication. ... human beings is carried out with the aid of communication and has facilitated the development ... Hidden Markov model-based approach for generation of PSL symbols. 279. Table 1. PSL basic strokes and English consonants. English consonant.
A novel Monte Carlo approach to hybrid local volatility models
van der Stoep, A.W.; Grzelak, L.A.; Oosterlee, C.W.
2017-01-01
We present in a Monte Carlo simulation framework, a novel approach for the evaluation of hybrid local volatility [Risk, 1994, 7, 18–20], [Int. J. Theor. Appl. Finance, 1998, 1, 61–110] models. In particular, we consider the stochastic local volatility model—see e.g. Lipton et al. [Quant. Finance,
Model-independent approach for dark matter phenomenology
Indian Academy of Sciences (India)
We have studied the phenomenology of dark matter at the ILC and cosmic positron experiments based on model-independent approach. We have found a strong correlation between dark matter signatures at the ILC and those in the indirect detection experiments of dark matter. Once the dark matter is discovered in the ...
Model-independent approach for dark matter phenomenology ...
Indian Academy of Sciences (India)
Abstract. We have studied the phenomenology of dark matter at the ILC and cosmic positron experiments based on model-independent approach. We have found a strong correlation between dark matter signatures at the ILC and those in the indirect detec- tion experiments of dark matter. Once the dark matter is discovered ...
Using artificial neural network approach for modelling rainfall–runoff ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Earth System Science; Volume 122; Issue 2. Using artificial neural network approach for modelling ... Nevertheless, water level and flow records are essential in hydrological analysis for designing related water works of flood management. Due to the complexity of the hydrological process, ...
An Approach to Quality Estimation in Model-Based Development
DEFF Research Database (Denmark)
Holmegaard, Jens Peter; Koch, Peter; Ravn, Anders Peter
2004-01-01
We present an approach to estimation of parameters for design space exploration in Model-Based Development, where synthesis of a system is done in two stages. Component qualities like space, execution time or power consumption are defined in a repository by platform dependent values. Connectors...
Hidden Markov model-based approach for generation of Pitman ...
Indian Academy of Sciences (India)
In this paper, an approach for feature extraction using Mel frequency cep- stral coefficients (MFCC) and classification using hidden Markov models (HMM) for generating strokes comprising consonants and vowels (CV) in the process of production of Pitman shorthand language from spoken English is proposed. The.
Pruning Chinese trees : an experimental and modelling approach
Zeng, Bo
2001-01-01
Pruning of trees, in which some branches are removed from the lower crown of a tree, has been extensively used in China in silvicultural management for many purposes. With an experimental and modelling approach, the effects of pruning on tree growth and on the harvest of plant material were studied.
Non-frontal Model Based Approach to Forensic Face Recognition
Dutta, A.; Veldhuis, Raymond N.J.; Spreeuwers, Lieuwe Jan
2012-01-01
In this paper, we propose a non-frontal model based approach which ensures that a face recognition system always gets to compare images having similar view (or pose). This requires a virtual suspect reference set that consists of non-frontal suspect images having pose similar to the surveillance
Reconciliation with oneself and with others: From approach to model
Directory of Open Access Journals (Sweden)
Nikolić-Ristanović Vesna
2010-01-01
Full Text Available The paper intends to present the approach to dealing with war and its consequences which was developed within Victimology Society of Serbia over the last five years, in the framework of Association Joint Action for Truth and Reconciliation (ZAIP. First, the short review of the Association and the process through which ZAIP approach to dealing with a past was developed is presented. Then, the detailed description of the approach itself, with identification of its most important specificities, is presented. In the conclusion, next steps, aimed at development of the model of reconciliation which will have the basis in ZAIP approach and which will be appropriate to social context of Serbia and its surrounding, are suggested.
EXTENDE MODEL OF COMPETITIVITY THROUG APPLICATION OF NEW APPROACH DIRECTIVES
Directory of Open Access Journals (Sweden)
Slavko Arsovski
2009-03-01
Full Text Available The basic subject of this work is the model of new approach impact on quality and safety products, and competency of our companies. This work represents real hypothesis on the basis of expert's experiences, in regard to that the infrastructure with using new approach directives wasn't examined until now, it isn't known which product or industry of Serbia is related to directives of the new approach and CE mark, and it is not known which are effects of the use of the CE mark. This work should indicate existing quality reserves and product's safety, the level of possible competency improvement and increasing the profit by discharging new approach directive requires.
Econometric modelling of Serbian current account determinants: Jackknife Model Averaging approach
Directory of Open Access Journals (Sweden)
Petrović Predrag
2014-01-01
Full Text Available This research aims to model Serbian current account determinants for the period Q1 2002 - Q4 2012. Taking into account the majority of relevant determinants, using the Jackknife Model Averaging approach, 48 different models have been estimated, where 1254 equations needed to be estimated and averaged for each of the models. The results of selected representative models indicate moderate persistence of the CA and positive influence of: fiscal balance, oil trade balance, terms of trade, relative income and real effective exchange rates, where we should emphasise: (i a rather strong influence of relative income, (ii the fact that the worsening of oil trade balance results in worsening of other components (probably non-oil trade balance of CA and (iii that the positive influence of terms of trade reveals functionality of the Harberger-Laursen-Metzler effect in Serbia. On the other hand, negative influence is evident in case of: relative economic growth, gross fixed capital formation, net foreign assets and trade openness. What particularly stands out is the strong effect of relative economic growth that, most likely, reveals high citizens' future income growth expectations, which has negative impact on the CA.
Surovyatkina, Elena; Stolbova, Veronika; Kurths, Jurgen
2017-04-01
started to decrease, and after two days meteorological stations reported 'No rain' in the EG and also in areas located across the subcontinent in the direction from the North Pakistan to the Bay of Bengal. Hence, the date of monsoon withdrawal - October 10-th, predicted 70 days in advance, lies within our prediction interval. Our results show that our method allows predicting a future monsoon, and not only retrospectively or hindcast. In 2016 we predicted of the onset and withdrawal dates of the Southwest monsoon over the Eastern Ghats region in Central India for 40 and 70 days in advance respectively. Our general framework for predicting spatial-temporal critical transitions is applicable for systems of different nature. It allows predicting future from observational data only, when the model of a transition does not exist yet. [1] Stolbova, V., E. Surovyatkina, B. Bookhagen, and J. Kurths (2016): Tipping elements of the Indian monsoon: Prediction of onset and withdrawal. Geophys. Res. Lett., 43, 1-9. [2]https://www.pik-potsdam.de/news/press-releases/indian-monsoon-novel-approach-allows-early-forecasting?set_language=en [3] https://www.pik-potsdam.de/kontakt/pressebuero/fotos/monsoon-withdrawal/view
Modeling electricity spot and futures price dependence: A multifrequency approach
Malo, Pekka
2009-11-01
Electricity prices are known to exhibit multifractal properties. We accommodate this finding by investigating multifractal models for electricity prices. In this paper we propose a flexible Copula-MSM (Markov Switching Multifractal) approach for modeling spot and weekly futures price dynamics. By using a conditional copula function, the framework allows us to separately model the dependence structure, while enabling use of multifractal stochastic volatility models to characterize fluctuations in marginal returns. An empirical experiment is carried out using data from Nord Pool. A study of volatility forecasting performance for electricity spot prices reveals that multifractal techniques are a competitive alternative to GARCH models. We also demonstrate how the Copula-MSM model can be employed for finding optimal portfolios, which minimizes the Conditional Value-at-Risk.
Multiphysics modeling using COMSOL a first principles approach
Pryor, Roger W
2011-01-01
Multiphysics Modeling Using COMSOL rapidly introduces the senior level undergraduate, graduate or professional scientist or engineer to the art and science of computerized modeling for physical systems and devices. It offers a step-by-step modeling methodology through examples that are linked to the Fundamental Laws of Physics through a First Principles Analysis approach. The text explores a breadth of multiphysics models in coordinate systems that range from 1D to 3D and introduces the readers to the numerical analysis modeling techniques employed in the COMSOL Multiphysics software. After readers have built and run the examples, they will have a much firmer understanding of the concepts, skills, and benefits acquired from the use of computerized modeling techniques to solve their current technological problems and to explore new areas of application for their particular technological areas of interest.
Evaluation of Workflow Management Systems - A Meta Model Approach
Directory of Open Access Journals (Sweden)
Michael Rosemann
1998-11-01
Full Text Available The automated enactment of processes through the use of workflow management systems enables the outsourcing of the control flow from application systems. By now a large number of systems, that follow different workflow paradigms, are available. This leads to the problem of selecting the appropriate workflow management system for a given situation. In this paper we outline the benefits of a meta model approach for the evaluation and comparison of different workflow management systems. After a general introduction on the topic of meta modeling the meta models of the workflow management systems WorkParty (Siemens Nixdorf and FlowMark (IBM are compared as an example. These product specific meta models can be generalized to meta reference models, which helps to specify a workflow methodology. Exemplary, an organisational reference meta model is presented, which helps users in specifying their requirements for a workflow management system.
Setting conservation management thresholds using a novel participatory modeling approach.
Addison, P F E; de Bie, K; Rumpff, L
2015-10-01
We devised a participatory modeling approach for setting management thresholds that show when management intervention is required to address undesirable ecosystem changes. This approach was designed to be used when management thresholds: must be set for environmental indicators in the face of multiple competing objectives; need to incorporate scientific understanding and value judgments; and will be set by participants with limited modeling experience. We applied our approach to a case study where management thresholds were set for a mat-forming brown alga, Hormosira banksii, in a protected area management context. Participants, including management staff and scientists, were involved in a workshop to test the approach, and set management thresholds to address the threat of trampling by visitors to an intertidal rocky reef. The approach involved trading off the environmental objective, to maintain the condition of intertidal reef communities, with social and economic objectives to ensure management intervention was cost-effective. Ecological scenarios, developed using scenario planning, were a key feature that provided the foundation for where to set management thresholds. The scenarios developed represented declines in percent cover of H. banksii that may occur under increased threatening processes. Participants defined 4 discrete management alternatives to address the threat of trampling and estimated the effect of these alternatives on the objectives under each ecological scenario. A weighted additive model was used to aggregate participants' consequence estimates. Model outputs (decision scores) clearly expressed uncertainty, which can be considered by decision makers and used to inform where to set management thresholds. This approach encourages a proactive form of conservation, where management thresholds and associated actions are defined a priori for ecological indicators, rather than reacting to unexpected ecosystem changes in the future. © 2015 The
Probabilistic approach in treatment of deterministic analyses results of severe accidents
International Nuclear Information System (INIS)
Krajnc, B.; Mavko, B.
1996-01-01
Severe accidents sequences resulting in loss of the core geometric integrity have been found to have small probability of the occurrence. Because of their potential consequences to public health and safety, an evaluation of the core degradation progression and the resulting effects on the containment is necessary to determine the probability of a significant release of radioactive materials. This requires assessment of many interrelated phenomena including: steel and zircaloy oxidation, steam spikes, in-vessel debris cooling, potential vessel failure mechanisms, release of core material to the containment, containment pressurization from steam generation, or generation of non-condensable gases or hydrogen burn, and ultimately coolability of degraded core material. To asses the answer from the containment event trees in the sense of weather certain phenomenological event would happen or not the plant specific deterministic analyses should be performed. Due to the fact that there is a large uncertainty in the prediction of severe accidents phenomena in Level 2 analyses (containment event trees) the combination of probabilistic and deterministic approach should be used. In fact the result of the deterministic analyses of severe accidents are treated in probabilistic manner due to large uncertainty of results as a consequence of a lack of detailed knowledge. This paper discusses approach used in many IPEs, and which assures that the assigned probability for certain question in the event tree represent the probability that the event will or will not happen and that this probability also includes its uncertainty, which is mainly result of lack of knowledge. (author)
Pizzichelli, G; Di Michele, F; Sinibaldi, E
2016-02-01
We consider the infusion of a diluted suspension of nanoparticles (NPs) into poroelastic brain tissue, in view of relevant biomedical applications such as intratumoral thermotherapy. Indeed, the high impact of the related pathologies motivates the development of advanced therapeutic approaches, whose design also benefits from theoretical models. This study provides an analytical expression for the time-dependent NPs concentration during the infusion into poroelastic brain tissue, which also accounts for particle binding onto cells (by recalling relevant results from the colloid filtration theory). Our model is computationally inexpensive and, compared to fully numerical approaches, permits to explicitly elucidate the role of the involved physical aspects (tissue poroelasticity, infusion parameters, NPs physico-chemical properties, NP-tissue interactions underlying binding). We also present illustrative results based on parameters taken from the literature, by considering clinically relevant ranges for the infusion parameters. Moreover, we thoroughly assess the model working assumptions besides discussing its limitations. While not laying any claims of generality, our model can be used to support the development of more ambitious numerical approaches, towards the preliminary design of novel therapies based on NPs infusion into brain tissue. Copyright © 2015 Elsevier Inc. All rights reserved.
Results of EPRI/ANL DCH investigations and model development
International Nuclear Information System (INIS)
Spencer, B.W.; Sienicki, J.J.; Sehgal, B.R.; Merilo, M.
1988-01-01
The results of a series of five experiments are described addressing the severity and mitigation of direct containment heating. The tests were performed in a 1:30 linear scale mockup of the Zion PWR containment system using a reactor-material corium melt consisting of 60% UO 2 , 16% ZrO 2 , 24% SSt at nominally 2800C initial temperature. A ''worst-case'' type test involving unimpeded corium dispersal through an air atmosphere in a closed vessel produced an atmosphere heatup of 323K, equivalent to a DCH efficiency of 62%. With the addition of structural features which impeded the corium dispersal, representative of dispersal pathway features at Zion, the DCH efficiency was reduced to 1--5%. (This important result is scale dependent and requires larger scale tests such as the SURTSEY program at SNL plus mechanistic modeling for application to the reactor system.) With the addition of water in the cavity region, there was no measurable heatup of the atmosphere. This was attributable to the vigorous codispersal of water with corium which prevented the temperature of the atmosphere from significantly exceeding T/sub sat/. In this case the DCH load was replaced by the more benign ''steam spike'' from corium quench. Significant oxidation of the corium constituents occurred in the tests, adding chemical energy to the system and producing hydrogen. Overall, the results suggest that with consideration of realistic, plant specific, mitigating features, DCH may be no worse and possibly far less severe than the previously examined steam spike. Implications for accident management are addressed. 17 refs., 7 figs., 4 tabs
Wimmer, Lena; Bellingrath, Silja; von Stockhausen, Lisa
2016-01-01
The present paper reports a pilot study which tested cognitive effects of mindfulness practice in a theory-driven approach. Thirty-four fifth graders received either a mindfulness training which was based on the mindfulness-based stress reduction approach (experimental group), a concentration training (active control group), or no treatment (passive control group). Based on the operational definition of mindfulness by Bishop et al. (2004), effects on sustained attention, cognitive flexibility, cognitive inhibition, and data-driven as opposed to schema-based information processing were predicted. These abilities were assessed in a pre-post design by means of a vigilance test, a reversible figures test, the Wisconsin Card Sorting Test, a Stroop test, a visual search task, and a recognition task of prototypical faces. Results suggest that the mindfulness training specifically improved cognitive inhibition and data-driven information processing.
Directory of Open Access Journals (Sweden)
Lena Wimmer
2016-07-01
Full Text Available The present paper reports a pilot study which tested cognitive effects of mindfulness practice in a theory-driven approach. Thirty-four fifth graders received either a mindfulness training which was based on the mindfulness-based stress reduction approach (experimental group, a concentration training (active control group or no treatment (passive control group. Based on the operational definition of mindfulness by Bishop et al. (2004, effects on sustained attention, cognitive flexibility, cognitive inhibition and data-driven as opposed to schema-based information processing were predicted. These abilities were assessed in a pre-post design by means of a vigilance test, a reversible figures test, the Wisconsin Card Sorting Test, a Stroop test, a visual search task, and a recognition task of prototypical faces. Results suggest that the mindfulness training specifically improved cognitive inhibition and data-driven information processing.
Data-driven approach to dynamic visual attention modelling
Culibrk, Dubravko; Sladojevic, Srdjan; Riche, Nicolas; Mancas, Matei; Crnojevic, Vladimir
2012-06-01
Visual attention deployment mechanisms allow the Human Visual System to cope with an overwhelming amount of visual data by dedicating most of the processing power to objects of interest. The ability to automatically detect areas of the visual scene that will be attended to by humans is of interest for a large number of applications, from video coding, video quality assessment to scene understanding. Due to this fact, visual saliency (bottom-up attention) models have generated significant scientific interest in recent years. Most recent work in this area deals with dynamic models of attention that deal with moving stimuli (videos) instead of traditionally used still images. Visual saliency models are usually evaluated against ground-truth eye-tracking data collected from human subjects. However, there are precious few recently published approaches that try to learn saliency from eyetracking data and, to the best of our knowledge, no approaches that try to do so when dynamic saliency is concerned. The paper attempts to fill this gap and describes an approach to data-driven dynamic saliency model learning. A framework is proposed that enables the use of eye-tracking data to train an arbitrary machine learning algorithm, using arbitrary features derived from the scene. We evaluate the methodology using features from a state-of-the art dynamic saliency model and show how simple machine learning algorithms can be trained to distinguish between visually salient and non-salient parts of the scene.
Common modelling approaches for training simulators for nuclear power plants
International Nuclear Information System (INIS)
1990-02-01
Training simulators for nuclear power plant operating staff have gained increasing importance over the last twenty years. One of the recommendations of the 1983 IAEA Specialists' Meeting on Nuclear Power Plant Training Simulators in Helsinki was to organize a Co-ordinated Research Programme (CRP) on some aspects of training simulators. The goal statement was: ''To establish and maintain a common approach to modelling for nuclear training simulators based on defined training requirements''. Before adapting this goal statement, the participants considered many alternatives for defining the common aspects of training simulator models, such as the programming language used, the nature of the simulator computer system, the size of the simulation computers, the scope of simulation. The participants agreed that it was the training requirements that defined the need for a simulator, the scope of models and hence the type of computer complex that was required, the criteria for fidelity and verification, and was therefore the most appropriate basis for the commonality of modelling approaches. It should be noted that the Co-ordinated Research Programme was restricted, for a variety of reasons, to consider only a few aspects of training simulators. This report reflects these limitations, and covers only the topics considered within the scope of the programme. The information in this document is intended as an aid for operating organizations to identify possible modelling approaches for training simulators for nuclear power plants. 33 refs
Estimating a DIF decomposition model using a random-weights linear logistic test model approach.
Paek, Insu; Fukuhara, Hirotaka
2015-09-01
A differential item functioning (DIF) decomposition model separates a testlet item DIF into two sources: item-specific differential functioning and testlet-specific differential functioning. This article provides an alternative model-building framework and estimation approach for a DIF decomposition model that was proposed by Beretvas and Walker (2012). Although their model is formulated under multilevel modeling with the restricted pseudolikelihood estimation method, our approach illustrates DIF decomposition modeling that is directly built upon the random-weights linear logistic test model framework with the marginal maximum likelihood estimation method. In addition to demonstrating our approach's performance, we provide detailed information on how to implement this new DIF decomposition model using an item response theory software program; using DIF decomposition may be challenging for practitioners, yet practical information on how to implement it has previously been unavailable in the measurement literature.
RELATIONSHIP BETWEEN ISO 9001 CERTIFICATION MATURITY AND EFQM BUSINESS EXCELLENCE MODEL RESULTS
Directory of Open Access Journals (Sweden)
Luis Miguel Fonseca
2015-07-01
Full Text Available Purpose: This exploratory research evaluates if there a relationship between the number of years since an organization has achieved ISO 9001 certification and the highest level of recognition received by the same organization with the EFQM Business Excellence Model.Methodology/Approach: After state of the art review a detailed comparison between both models was made. Fifty two Portuguese organizations were considered and Correlation coefficient Spearman Rho was used to investigate the possible relationships.Findings: Conclusion is that there is indeed a moderate positive correlation between these two variables, the higher the number of years of ISO 9001 certification, the higher the results of the organization EFQM model evaluation and recognition. This supports the assumption that ISO 9001 International Standard by incorporating many of the principles present in the EFQM Business Excellence Model is consistent with this model and can be considered as a step towards that direction.Research Limitation/implication: Due to the dynamic nature of these models that might change over time and the possible time delays between implementation and results, more in-depth studies like experimental design or a longitudinal quasi-experimental design could be used to confirm the results of this investigation.Originality/Value of paper: This research gives additional insights on conjunct studies of both models. The use of external evaluation results carried out by the independent EFQM assessors minimizes the possible bias of previous studies accessing the value of ISO 9001 certification.
Results from ITMIX - the Ice Thickness Models Intercomparison eXperiment
Farinotti, Daniel; Itmix Consortium, The
2017-04-01
Knowledge about the ice thickness distribution of a given glacier or ice cap is essential for a number of glaciological and hydrological applications. Yet, the ice thickness of the majority of worlds' ice masses remains poorly constrained. Recently, significant advances have been made in numerical methods that infer glacier ice thickness from surface characteristics, and a number of approaches have been proposed. A comprehensive assessment of their performance, however, is missing to date. Here, we present results from ITMIX - the Ice Thickness Models Intercomparison eXperiment - which was the first coordinated effort to assess the relative strengths and weaknesses of individual approaches. Operating in a working group of the International Association of Cryospheric Sciences, we present results from a total of 17 different models, applied over 21 test cases including glaciers, ice caps, and synthetic geometries. We show that the results from individual approaches can differ largely, but that combining them into an ensemble-estimate can yield significantly improvements. Comparison against direct ice thickness measurements reveals that ensemble solution can achieve accuracies in the order of 10 ± 24 % of the mean ice thickness. We additionally highlight how input-data quality can affect the estimates, and argue that better accounting for input-data uncertainty will be a key for an improved next generation of ice thickness estimation models.
Strokal, Maryna; Kroeze, Carolien; Wang, Mengru; Bai, Zhaohai; Ma, Lin
2016-08-15
Chinese agriculture has been developing fast towards industrial food production systems that discharge nutrient-rich wastewater into rivers. As a result, nutrient export by rivers has been increasing, resulting in coastal water pollution. We developed a Model to Assess River Inputs of Nutrients to seAs (MARINA) for China. The MARINA Nutrient Model quantifies river export of nutrients by source at the sub-basin scale as a function of human activities on land. MARINA is a downscaled version for China of the Global NEWS-2 (Nutrient Export from WaterSheds) model with an improved approach for nutrient losses from animal production and population. We use the model to quantify dissolved inorganic and organic nitrogen (N) and phosphorus (P) export by six large rivers draining into the Bohai Gulf (Yellow, Hai, Liao), Yellow Sea (Yangtze, Huai) and South China Sea (Pearl) in 1970, 2000 and 2050. We addressed uncertainties in the MARINA Nutrient model. Between 1970 and 2000 river export of dissolved N and P increased by a factor of 2-8 depending on sea and nutrient form. Thus, the risk for coastal eutrophication increased. Direct losses of manure to rivers contribute to 60-78% of nutrient inputs to the Bohai Gulf and 20-74% of nutrient inputs to the other seas in 2000. Sewage is an important source of dissolved inorganic P, and synthetic fertilizers of dissolved inorganic N. Over half of the nutrients exported by the Yangtze and Pearl rivers originated from human activities in downstream and middlestream sub-basins. The Yellow River exported up to 70% of dissolved inorganic N and P from downstream sub-basins and of dissolved organic N and P from middlestream sub-basins. Rivers draining into the Bohai Gulf are drier, and thus transport fewer nutrients. For the future we calculate further increases in river export of nutrients. The MARINA Nutrient model quantifies the main sources of coastal water pollution for sub-basins. This information can contribute to formulation of
A Duality Result for the Generalized Erlang Risk Model
Directory of Open Access Journals (Sweden)
Lanpeng Ji
2014-11-01
Full Text Available In this article, we consider the generalized Erlang risk model and its dual model. By using a conditional measure-preserving correspondence between the two models, we derive an identity for two interesting conditional probabilities. Applications to the discounted joint density of the surplus prior to ruin and the deficit at ruin are also discussed.
Energy Technology Data Exchange (ETDEWEB)
Yang, Zhaoqing; Khangaonkar, Tarang; Wang, Taiping
2010-08-01
In this report we describe the 1) the expansion of the PNNL hydrodynamic model domain to include the continental shelf along the coasts of Washington, Oregon, and Vancouver Island; and 2) the approach and progress in developing the online/Internet disseminations of model results and outreach efforts in support of the Puget Sound Operational Forecast System (PS-OPF). Submittal of this report completes the work on Task 2.1.2, Effects of Physical Systems, Subtask 2.1.2.1, Hydrodynamics, for fiscal year 2010 of the Environmental Effects of Marine and Hydrokinetic Energy project.
International Nuclear Information System (INIS)
Yang, Zhaoqing; Khangaonkar, Tarang; Wang, Taiping
2010-01-01
In this report we describe the (1) the expansion of the PNNL hydrodynamic model domain to include the continental shelf along the coasts of Washington, Oregon, and Vancouver Island; and (2) the approach and progress in developing the online/Internet disseminations of model results and outreach efforts in support of the Puget Sound Operational Forecast System (PS-OPF). Submittal of this report completes the work on Task 2.1.2, Effects of Physical Systems, Subtask 2.1.2.1, Hydrodynamics, for fiscal year 2010 of the Environmental Effects of Marine and Hydrokinetic Energy project.
A new multi-objective approach to finite element model updating
Jin, Seung-Seop; Cho, Soojin; Jung, Hyung-Jo; Lee, Jong-Jae; Yun, Chung-Bang
2014-05-01
The single objective function (SOF) has been employed for the optimization process in the conventional finite element (FE) model updating. The SOF balances the residual of multiple properties (e.g., modal properties) using weighting factors, but the weighting factors are hard to determine before the run of model updating. Therefore, the trial-and-error strategy is taken to find the most preferred model among alternative updated models resulted from varying weighting factors. In this study, a new approach to the FE model updating using the multi-objective function (MOF) is proposed to get the most preferred model in a single run of updating without trial-and-error. For the optimization using the MOF, non-dominated sorting genetic algorithm-II (NSGA-II) is employed to find the Pareto optimal front. The bend angle related to the trade-off relationship of objective functions is used to select the most preferred model among the solutions on the Pareto optimal front. To validate the proposed approach, a highway bridge is selected as a test-bed and the modal properties of the bridge are obtained from the ambient vibration test. The initial FE model of the bridge is built using SAP2000. The model is updated using the identified modal properties by the SOF approach with varying the weighting factors and the proposed MOF approach. The most preferred model is selected using the bend angle of the Pareto optimal front, and compared with the results from the SOF approach using varying the weighting factors. The comparison shows that the proposed MOF approach is superior to the SOF approach using varying the weighting factors in getting smaller objective function values, estimating better updated parameters, and taking less computational time.
Plenary lecture: innovative modeling approaches applicable to risk assessments.
Oscar, T P
2011-06-01
Proper identification of safe and unsafe food at the processing plant is important for maximizing the public health benefit of food by ensuring both its consumption and safety. Risk assessment is a holistic approach to food safety that consists of four steps: 1) hazard identification; 2) exposure assessment; 3) hazard characterization; and 4) risk characterization. Risk assessments are modeled by mapping the risk pathway as a series of unit operations and associated pathogen events and then using probability distributions and a random sampling method to simulate the rare, random, variable and uncertain nature of pathogen events in the risk pathway. To model pathogen events, a rare event modeling approach is used that links a discrete distribution for incidence of the pathogen event with a continuous distribution for extent of the pathogen event. When applied to risk assessment, rare event modeling leads to the conclusion that the most highly contaminated food at the processing plant does not necessarily pose the highest risk to public health because of differences in post-processing risk factors among distribution channels and consumer populations. Predictive microbiology models for individual pathogen events can be integrated with risk assessment models using the rare event modeling method. Published by Elsevier Ltd.
A global sensitivity analysis approach for morphogenesis models.
Boas, Sonja E M; Navarro Jimenez, Maria I; Merks, Roeland M H; Blom, Joke G
2015-11-21
Morphogenesis is a developmental process in which cells organize into shapes and patterns. Complex, non-linear and multi-factorial models with images as output are commonly used to study morphogenesis. It is difficult to understand the relation between the uncertainty in the input and the output of such 'black-box' models, giving rise to the need for sensitivity analysis tools. In this paper, we introduce a workflow for a global sensitivity analysis approach to study the impact of single parameters and the interactions between them on the output of morphogenesis models. To demonstrate the workflow, we used a published, well-studied model of vascular morphogenesis. The parameters of this cellular Potts model (CPM) represent cell properties and behaviors that drive the mechanisms of angiogenic sprouting. The global sensitivity analysis correctly identified the dominant parameters in the model, consistent with previous studies. Additionally, the analysis provided information on the relative impact of single parameters and of interactions between them. This is very relevant because interactions of parameters impede the experimental verification of the predicted effect of single parameters. The parameter interactions, although of low impact, provided also new insights in the mechanisms of in silico sprouting. Finally, the analysis indicated that the model could be reduced by one parameter. We propose global sensitivity analysis as an alternative approach to study the mechanisms of morphogenesis. Comparison of the ranking of the impact of the model parameters to knowledge derived from experimental data and from manipulation experiments can help to falsify models and to find the operand mechanisms in morphogenesis. The workflow is applicable to all 'black-box' models, including high-throughput in vitro models in which output measures are affected by a set of experimental perturbations.
A fuzzy approach for modelling radionuclide in lake system
International Nuclear Information System (INIS)
Desai, H.K.; Christian, R.A.; Banerjee, J.; Patra, A.K.
2013-01-01
Radioactive liquid waste is generated during operation and maintenance of Pressurised Heavy Water Reactors (PHWRs). Generally low level liquid waste is diluted and then discharged into the near by water-body through blowdown water discharge line as per the standard waste management practice. The effluents from nuclear installations are treated adequately and then released in a controlled manner under strict compliance of discharge criteria. An attempt was made to predict the concentration of 3 H released from Kakrapar Atomic Power Station at Ratania Regulator, about 2.5 km away from the discharge point, where human exposure is expected. Scarcity of data and complex geometry of the lake prompted the use of Heuristic approach. Under this condition, Fuzzy rule based approach was adopted to develop a model, which could predict 3 H concentration at Ratania Regulator. Three hundred data were generated for developing the fuzzy rules, in which input parameters were water flow from lake and 3 H concentration at discharge point. The Output was 3 H concentration at Ratania Regulator. These data points were generated by multiple regression analysis of the original data. Again by using same methodology hundred data were generated for the validation of the model, which were compared against the predicted output generated by using Fuzzy Rule based approach. Root Mean Square Error of the model came out to be 1.95, which showed good agreement by Fuzzy model of natural ecosystem. -- Highlights: • Uncommon approach (Fuzzy Rule Base) of modelling radionuclide dispersion in Lake. • Predicts 3 H released from Kakrapar Atomic Power Station at a point of human exposure. • RMSE of fuzzy model is 1.95, which means, it has well imitated natural ecosystem
Review of solution approach, methods, and recent results of the RELAP5 system code
International Nuclear Information System (INIS)
Trapp, J.A.; Ransom, V.H.
1983-01-01
The present RELAP5 code is based on a semi-implicit numerical scheme for the hydrodynamic model. The basic guidelines employed in the development of the semi-implicit numerical scheme are discussed and the numerical features of the scheme are illustrated by analysis for a simple, but analogous, single-equation model. The basic numerical scheme is recorded and results from several simulations are presented. The experimental results and code simulations are used in a complementary fashion to develop insights into nuclear-plant response that would not be obtained if either tool were used alone. Further analysis using the simple single-equation model is carried out to yield insights that are presently being used to implement a more-implicit multi-step scheme in the experimental version of RELAP5. The multi-step implicit scheme is also described
Shafii, Mahyar; Basu, Nandita; Craig, James R.; Schiff, Sherry L.; Van Cappellen, Philippe
2017-04-01
Hydrologic models are often tasked with replicating historical hydrographs but may do so without accurately reproducing the internal hydrological functioning of the watershed, including the flow partitioning, which is critical for predicting solute movement through the catchment. Here we propose a novel partitioning-focused calibration technique that utilizes flow-partitioning coefficients developed based on the pioneering work of L'vovich (1979). Our hypothesis is that inclusion of the L'vovich partitioning relations in calibration increases model consistency and parameter identifiability and leads to superior model performance with respect to flow partitioning than using traditional hydrological signatures (e.g., flow duration curve indices) alone. The L'vovich approach partitions the annual precipitation into four components (quick flow, soil wetting, slow flow, and evapotranspiration) and has been shown to work across a range of climatic and landscape settings. A new diagnostic multicriteria model calibration methodology is proposed that first quantifies four calibration measures for watershed functions based on the L'vovich theory, and then utilizes them as calibration criteria. The proposed approach is compared with a traditional hydrologic signature-based calibration for two conceptual bucket models. Results reveal that the proposed approach not only improves flow partitioning in the model compared to signature-based calibration but is also capable of diagnosing flow-partitioning inaccuracy and suggesting relevant model improvements. Furthermore, the proposed partitioning-based calibration approach is shown to increase parameter identifiability. This model calibration approach can be readily applied to other models.
Energy Technology Data Exchange (ETDEWEB)
Coughlin, Katie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Shen, Hongxia [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Chan, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; McDevitt, Brian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Sturges, Andrew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division
2013-02-07
Policies aimed at energy conservation and efficiency have broad environmental and economic impacts. Even if these impacts are relatively small, they may be significant compared to the cost of implementing the policy. Methodologies that quantify the marginal impacts of reduced demand for energy have an important role to play in developing accurate measures of both the benefits and costs of a given policy choice. This report presents a methodology for estimating the impacts of reduced demand for electricity on the electric power sector as a whole. The approach uses the National Energy Modeling System (NEMS), a mid-range energy forecast model developed and maintained by the U.S. Department of Energy, Energy Information Administration (EIA)(DOE EIA 2013). The report is organized as follows: In the rest of this section the traditional NEMS-BT approach is reviewed and an outline of the new reduced form NEMS methodology is presented. Section 2 provides an overview of how the NEMS model works, and describes the set of NEMS-BT runs that are used as input to the reduced form approach. Section 3 presents our NEMS-BT simulation results and post-processing methods. In Section 4 we show how the NEMS-BT output can be generalized to apply to a broader set of end-uses. In Section 5 we disuss the application of this approach to policy analysis, and summarize some of the issues that will be further investigated in Part 2 of this study.
Waste glass corrosion modeling: Comparison with experimental results
International Nuclear Information System (INIS)
Bourcier, W.L.
1994-01-01
Models for borosilicate glass dissolution must account for the processes of (1) kinetically-controlled network dissolution, (2) precipitation of secondary phases, (3) ion exchange, (4) rate-limiting diffusive transport of silica through a hydrous surface reaction layer, and (5) specific glass surface interactions with dissolved cations and anions. Current long-term corrosion models for borosilicate glass employ a rate equation consistent with transition state theory embodied in a geochemical reaction-path modeling program that calculates aqueous phase speciation and mineral precipitation/dissolution. These models are currently under development. Future experimental and modeling work to better quantify the rate-controlling processes and validate these models are necessary before the models can be used in repository performance assessment calculations
Modeling magnetic circular dichroism within the polarizable embedding approach
DEFF Research Database (Denmark)
Nørby, Morten Steen; Coriani, Sonia; Kongsted, Jacob
2018-01-01
Magnetic circular dichroism (MCD) is defined as the differential absorption of left and right circularly polarized light in a sample subjected to an external magnetic field. In order to interpret the results of MCD measurements, theoretical predictions of key MCD parameters can be of utmost...... of the more conventional dielectric continuum approach. Results are presented for cytosine and hypoxanthine solvated in water....
Argonne Fuel Cycle Facility ventilation system -- modeling and results
International Nuclear Information System (INIS)
Mohr, D.; Feldman, E.E.; Danielson, W.F.
1995-01-01
This paper describes an integrated study of the Argonne-West Fuel Cycle Facility (FCF) interconnected ventilation systems during various operations. Analyses and test results include first a nominal condition reflecting balanced pressures and flows followed by several infrequent and off-normal scenarios. This effort is the first study of the FCF ventilation systems as an integrated network wherein the hydraulic effects of all major air systems have been analyzed and tested. The FCF building consists of many interconnected regions in which nuclear fuel is handled, transported and reprocessed. The ventilation systems comprise a large number of ducts, fans, dampers, and filters which together must provide clean, properly conditioned air to the worker occupied spaces of the facility while preventing the spread of airborne radioactive materials to clean am-as or the atmosphere. This objective is achieved by keeping the FCF building at a partial vacuum in which the contaminated areas are kept at lower pressures than the other worker occupied spaces. The ventilation systems of FCF and the EBR-II reactor are analyzed as an integrated totality, as demonstrated. We then developed the network model shown in Fig. 2 for the TORAC code. The scope of this study was to assess the measured results from the acceptance/flow balancing testing and to predict the effects of power failures, hatch and door openings, single-failure faulted conditions, EBR-II isolation, and other infrequent operations. The studies show that the FCF ventilation systems am very controllable and remain stable following off-normal events. In addition, the FCF ventilation system complex is essentially immune to reverse flows and spread of contamination to clean areas during normal and off-normal operation
ExEP yield modeling tool and validation test results
Morgan, Rhonda; Turmon, Michael; Delacroix, Christian; Savransky, Dmitry; Garrett, Daniel; Lowrance, Patrick; Liu, Xiang Cate; Nunez, Paul
2017-09-01
EXOSIMS is an open-source simulation tool for parametric modeling of the detection yield and characterization of exoplanets. EXOSIMS has been adopted by the Exoplanet Exploration Programs Standards Definition and Evaluation Team (ExSDET) as a common mechanism for comparison of exoplanet mission concept studies. To ensure trustworthiness of the tool, we developed a validation test plan that leverages the Python-language unit-test framework, utilizes integration tests for selected module interactions, and performs end-to-end crossvalidation with other yield tools. This paper presents the test methods and results, with the physics-based tests such as photometry and integration time calculation treated in detail and the functional tests treated summarily. The test case utilized a 4m unobscured telescope with an idealized coronagraph and an exoplanet population from the IPAC radial velocity (RV) exoplanet catalog. The known RV planets were set at quadrature to allow deterministic validation of the calculation of physical parameters, such as working angle, photon counts and integration time. The observing keepout region was tested by generating plots and movies of the targets and the keepout zone over a year. Although the keepout integration test required the interpretation of a user, the test revealed problems in the L2 halo orbit and the parameterization of keepout applied to some solar system bodies, which the development team was able to address. The validation testing of EXOSIMS was performed iteratively with the developers of EXOSIMS and resulted in a more robust, stable, and trustworthy tool that the exoplanet community can use to simulate exoplanet direct-detection missions from probe class, to WFIRST, up to large mission concepts such as HabEx and LUVOIR.
A Nonparametric Operational Risk Modeling Approach Based on Cornish-Fisher Expansion
Directory of Open Access Journals (Sweden)
Xiaoqian Zhu
2014-01-01
Full Text Available It is generally accepted that the choice of severity distribution in loss distribution approach has a significant effect on the operational risk capital estimation. However, the usually used parametric approaches with predefined distribution assumption might be not able to fit the severity distribution accurately. The objective of this paper is to propose a nonparametric operational risk modeling approach based on Cornish-Fisher expansion. In this approach, the samples of severity are generated by Cornish-Fisher expansion and then used in the Monte Carlo simulation to sketch the annual operational loss distribution. In the experiment, the proposed approach is employed to calculate the operational risk capital charge for the overall Chinese banking. The experiment dataset is the most comprehensive operational risk dataset in China as far as we know. The results show that the proposed approach is able to use the information of high order moments and might be more effective and stable than the usually used parametric approach.
Final model independent result of DAMA/LIBRA-phase1
Energy Technology Data Exchange (ETDEWEB)
Bernabei, R.; D' Angelo, S.; Di Marco, A. [Universita di Roma ' ' Tor Vergata' ' , Dipartimento di Fisica, Rome (Italy); INFN, sez. Roma ' ' Tor Vergata' ' , Rome (Italy); Belli, P. [INFN, sez. Roma ' ' Tor Vergata' ' , Rome (Italy); Cappella, F.; D' Angelo, A.; Prosperi, D. [Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, Rome (Italy); INFN, sez. Roma, Rome (Italy); Caracciolo, V.; Castellano, S.; Cerulli, R. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Dai, C.J.; He, H.L.; Kuang, H.H.; Ma, X.H.; Sheng, X.D.; Wang, R.G. [Chinese Academy, IHEP, Beijing (China); Incicchitti, A. [INFN, sez. Roma, Rome (Italy); Montecchia, F. [INFN, sez. Roma ' ' Tor Vergata' ' , Rome (Italy); Universita di Roma ' ' Tor Vergata' ' , Dipartimento di Ingegneria Civile e Ingegneria Informatica, Rome (Italy); Ye, Z.P. [Chinese Academy, IHEP, Beijing (China); University of Jing Gangshan, Jiangxi (China)
2013-12-15
The results obtained with the total exposure of 1.04 ton x yr collected by DAMA/LIBRA-phase1 deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. during 7 annual cycles (i.e. adding a further 0.17 ton x yr exposure) are presented. The DAMA/LIBRA-phase1 data give evidence for the presence of Dark Matter (DM) particles in the galactic halo, on the basis of the exploited model independent DM annual modulation signature by using highly radio-pure NaI(Tl) target, at 7.5{sigma} C.L. Including also the first generation DAMA/NaI experiment (cumulative exposure 1.33 ton x yr, corresponding to 14 annual cycles), the C.L. is 9.3{sigma} and the modulation amplitude of the single-hit events in the (2-6) keV energy interval is: (0.0112{+-}0.0012) cpd/kg/keV; the measured phase is (144{+-}7) days and the measured period is (0.998{+-}0.002) yr, values well in agreement with those expected for DM particles. No systematic or side reaction able to mimic the exploited DM signature has been found or suggested by anyone over more than a decade. (orig.)
Innovation ecosystem model for commercialization of research results
Directory of Open Access Journals (Sweden)
Vlăduţ Gabriel
2017-07-01
Full Text Available Innovation means Creativity and Added value recognise by the market. The first step in creating a sustainable commercialization of research results, Technological Transfer – TT mechanism, on one hand is to define the “technology” which will be transferred and on other hand to define the context in which the TT mechanism work, the ecosystem. The focus must be set on technology as an entity, not as a science or a study of the practical industrial arts and certainly not any specific applied science. The transfer object, the technology, must rely on a subjectively determined but specifiable set of processes and products. Focusing on the product is not sufficient to the transfer and diffusion of technology. It is not merely the product that is transferred but also knowledge of its use and application. The innovation ecosystem model brings together new companies, experienced business leaders, researchers, government officials, established technology companies, and investors. This environment provides those new companies with a wealth of technical expertise, business experience, and access to capital that supports innovation in the early stages of growth.
Bayesian approach to errors-in-variables in regression models
Rozliman, Nur Aainaa; Ibrahim, Adriana Irawati Nur; Yunus, Rossita Mohammad
2017-05-01
In many applications and experiments, data sets are often contaminated with error or mismeasured covariates. When at least one of the covariates in a model is measured with error, Errors-in-Variables (EIV) model can be used. Measurement error, when not corrected, would cause misleading statistical inferences and analysis. Therefore, our goal is to examine the relationship of the outcome variable and the unobserved exposure variable given the observed mismeasured surrogate by applying the Bayesian formulation to the EIV model. We shall extend the flexible parametric method proposed by Hossain and Gustafson (2009) to another nonlinear regression model which is the Poisson regression model. We shall then illustrate the application of this approach via a simulation study using Markov chain Monte Carlo sampling methods.
A new approach for modelling variability in residential construction projects
Directory of Open Access Journals (Sweden)
Mehrdad Arashpour
2013-06-01
Full Text Available The construction industry is plagued by long cycle times caused by variability in the supply chain. Variations or undesirable situations are the result of factors such as non-standard practices, work site accidents, inclement weather conditions and faults in design. This paper uses a new approach for modelling variability in construction by linking relative variability indicators to processes. Mass homebuilding sector was chosen as the scope of the analysis because data is readily available. Numerous simulation experiments were designed by varying size of capacity buffers in front of trade contractors, availability of trade contractors, and level of variability in homebuilding processes. The measurements were shown to lead to an accurate determination of relationships between these factors and production parameters. The variability indicator was found to dramatically affect the tangible performance measures such as home completion rates. This study provides for future analysis of the production homebuilding sector, which may lead to improvements in performance and a faster product delivery to homebuyers.
A new approach for modelling variability in residential construction projects
Directory of Open Access Journals (Sweden)
Mehrdad Arashpour
2013-06-01
Full Text Available The construction industry is plagued by long cycle times caused by variability in the supply chain. Variations or undesirable situations are the result of factors such as non-standard practices, work site accidents, inclement weather conditions and faults in design. This paper uses a new approach for modelling variability in construction by linking relative variability indicators to processes. Mass homebuilding sector was chosen as the scope of the analysis because data is readily available. Numerous simulation experiments were designed by varying size of capacity buffers in front of trade contractors, availability of trade contractors, and level of variability in homebuilding processes. The measurements were shown to lead to an accurate determination of relationships between these factors and production parameters. The variability indicator was found to dramatically affect the tangible performance measures such as home completion rates. This study provides for future analysis of the production homebuilding sector, which may lead to improvements in performance and a faster product delivery to homebuyers.
An approach to accidents modeling based on compounds road environments.
Fernandes, Ana; Neves, Jose
2013-04-01
The most common approach to study the influence of certain road features on accidents has been the consideration of uniform road segments characterized by a unique feature. However, when an accident is related to the road infrastructure, its cause is usually not a single characteristic but rather a complex combination of several characteristics. The main objective of this paper is to describe a methodology developed in order to consider the road as a complete environment by using compound road environments, overcoming the limitations inherented in considering only uniform road segments. The methodology consists of: dividing a sample of roads into segments; grouping them into quite homogeneous road environments using cluster analysis; and identifying the influence of skid resistance and texture depth on road accidents in each environment by using generalized linear models. The application of this methodology is demonstrated for eight roads. Based on real data from accidents and road characteristics, three compound road environments were established where the pavement surface properties significantly influence the occurrence of accidents. Results have showed clearly that road environments where braking maneuvers are more common or those with small radii of curvature and high speeds require higher skid resistance and texture depth as an important contribution to the accident prevention. Copyright © 2013 Elsevier Ltd. All rights reserved.
Gramatica, Paola; Cassani, Stefano; Sangion, Alessandro
2015-04-01
The limited availability of comprehensive data for Persistence, Bioaccumulation and Toxicity (PBT) of chemicals is a serious hindrance to the assignment of compounds to the categories of PBT and vPvB; REACH regulation requires authorization for the use of such chemicals, and additionally plans for safer alternatives. In the context of screening and priority-setting tools for PBT-assessment, the cumulative PBT Index model, implemented in QSARINS (QSAR-INSUBRIA), new software tool for the development and validation of multiple linear regression QSAR models, offers a new holistic approach for the identification of chemicals with cumulative PBT properties directly from their molecular structure. In this study the Insubria PBT Index in QSARINS is applied to the screening and prioritization of various data sets, containing a large variety of chemicals of heterogeneous molecular structure, previously screened by various authors by different methods, for their potential PBT behavior. Particular attention is devoted to the model Applicability Domain, using different approaches such as Descriptor Range, Leverage, and Principal Component Analysis (PCA) of the modeling molecular descriptors, in order to discriminate between interpolated and extrapolated predictions. The results of this screening, which is based only on the molecular structure features and is not dependent on single threshold values for P, B and T, are compared with those obtained by the on-line US-EPA PBT Profiler. Good agreement between the various approaches is found, supporting the utility of a consensus approach in priority-setting studies. The main discrepancies are highlighted and commented on. Moreover, a priority list containing the most hazardous compounds identified in agreement between the two tools is drafted. The PBT Index, implemented in QSARINS, which was demonstrated to be a practical, precautionary and reliable screening tool for PBT-behavior directly from the molecular structure, can be
Quantitative comparison of canopy conductance models using a Bayesian approach
Samanta, S.; Clayton, M. K.; Mackay, D. S.; Kruger, E. L.; Ewers, B. E.
2008-09-01
A quantitative model comparison methodology based on deviance information criterion, a Bayesian measure of the trade-off between model complexity and goodness of fit, is developed and demonstrated by comparing semiempirical transpiration models. This methodology accounts for parameter and prediction uncertainties associated with such models and facilitates objective selection of the simplest model, out of available alternatives, which does not significantly compromise the ability to accurately model observations. We use this methodology to compare various Jarvis canopy conductance model configurations, embedded within a larger transpiration model, against canopy transpiration measured by sap flux. The results indicate that descriptions of the dependence of stomatal conductance on vapor pressure deficit, photosynthetic radiation, and temperature, as well as the gradual variation in canopy conductance through the season are essential in the transpiration model. Use of soil moisture was moderately significant, but only when used with a hyperbolic vapor pressure deficit relationship. Subtle differences in model quality could be clearly associated with small structural changes through the use of this methodology. The results also indicate that increments in model complexity are not always accompanied by improvements in model quality and that such improvements are conditional on model structure. Possible application of this methodology to compare complex semiempirical models of natural systems in general is also discussed.
A Boolean Approach to Airline Business Model Innovation
DEFF Research Database (Denmark)
Hvass, Kristian Anders
Research in business model innovation has identified its significance in creating a sustainable competitive advantage for a firm, yet there are few empirical studies identifying which combination of business model activities lead to success and therefore deserve innovative attention. This study...... analyzes the business models of North America low-cost carriers from 2001 to 2010 using a Boolean minimization algorithm to identify which combinations of business model activities lead to operational profitability. The research aim is threefold: complement airline literature in the realm of business model...... innovation, introduce Boolean minimization methods to the field, and propose alternative business model activities to North American carriers striving for positive operating results....
Dalrymple, Kristy L.; Morgan, Theresa A.; Lipschitz, Jessica M.; Martinez, Jennifer H.; Tepe, Elizabeth; Zimmerman, Mark
2016-01-01
Depression and social anxiety disorder (SAD) are highly comorbid, resulting in greater severity and functional impairment compared with each disorder alone. Although recently transdiagnostic treatments have been developed, no known treatments have addressed this comorbidity pattern specifically. Preliminary support exists for acceptance-based approaches for depression and SAD separately, and they may be more efficacious for comorbid depression and anxiety compared with traditional cognitive-behavioral approaches. The aim of the current study was to develop and pilot test an integrated acceptance-based behavioral treatment for depression and comorbid SAD. Participants included 38 patients seeking pharmacotherapy at an outpatient psychiatry practice, who received 16 individual sessions of the therapy. Results showed significant improvement in symptoms, functioning, and processes from pre- to post-treatment, as well as high satisfaction with the treatment. These results support the preliminary acceptability, feasibility, and effectiveness of this treatment in a typical outpatient psychiatry practice, and suggest that further research on this treatment in larger randomized trials is warranted. PMID:24402463
PRESENTING SEARCH RESULT WITH REDUCED UNWANTED WEB ADDRESSES USING FUZZY BASED APPROACH
Directory of Open Access Journals (Sweden)
Nancy Jasmine Goldena
2017-07-01
Full Text Available Big Data is now the most talked about research subject. Over the year with the internet and storage space expansions vast swaths of data are available for would be searcher. About a decade ago when a content was searched, due to minimum amount of content often you end up with accurate set of results. But nowadays most of the data, if not all are sometimes vague and not even sometime pertain to area of search it was indented to. Hence here a novel approach is presented to perform data cleaning using a simple but effective fuzzy rule to weed out data that won’t produce accurate data.
Risk evaluation of uranium mining: A geochemical inverse modelling approach
Rillard, J.; Zuddas, P.; Scislewski, A.
2011-12-01
It is well known that uranium extraction operations can increase risks linked to radiation exposure. The toxicity of uranium and associated heavy metals is the main environmental concern regarding exploitation and processing of U-ore. In areas where U mining is planned, a careful assessment of toxic and radioactive element concentrations is recommended before the start of mining activities. A background evaluation of harmful elements is important in order to prevent and/or quantify future water contamination resulting from possible migration of toxic metals coming from ore and waste water interaction. Controlled leaching experiments were carried out to investigate processes of ore and waste (leached ore) degradation, using samples from the uranium exploitation site located in Caetité-Bahia, Brazil. In experiments in which the reaction of waste with water was tested, we found that the water had low pH and high levels of sulphates and aluminium. On the other hand, in experiments in which ore was tested, the water had a chemical composition comparable to natural water found in the region of Caetité. On the basis of our experiments, we suggest that waste resulting from sulphuric acid treatment can induce acidification and salinization of surface and ground water. For this reason proper storage of waste is imperative. As a tool to evaluate the risks, a geochemical inverse modelling approach was developed to estimate the water-mineral interaction involving the presence of toxic elements. We used a method earlier described by Scislewski and Zuddas 2010 (Geochim. Cosmochim. Acta 74, 6996-7007) in which the reactive surface area of mineral dissolution can be estimated. We found that the reactive surface area of rock parent minerals is not constant during time but varies according to several orders of magnitude in only two months of interaction. We propose that parent mineral heterogeneity and particularly, neogenic phase formation may explain the observed variation of the
A screening-level modeling approach to estimate nitrogen ...
This paper presents a screening-level modeling approach that can be used to rapidly estimate nutrient loading and assess numerical nutrient standard exceedance risk of surface waters leading to potential classification as impaired for designated use. It can also be used to explore best management practice (BMP) implementation to reduce loading. The modeling framework uses a hybrid statistical and process based approach to estimate source of pollutants, their transport and decay in the terrestrial and aquatic parts of watersheds. The framework is developed in the ArcGIS environment and is based on the total maximum daily load (TMDL) balance model. Nitrogen (N) is currently addressed in the framework, referred to as WQM-TMDL-N. Loading for each catchment includes non-point sources (NPS) and point sources (PS). NPS loading is estimated using export coefficient or event mean concentration methods depending on the temporal scales, i.e., annual or daily. Loading from atmospheric deposition is also included. The probability of a nutrient load to exceed a target load is evaluated using probabilistic risk assessment, by including the uncertainty associated with export coefficients of various land uses. The computed risk data can be visualized as spatial maps which show the load exceedance probability for all stream segments. In an application of this modeling approach to the Tippecanoe River watershed in Indiana, USA, total nitrogen (TN) loading and risk of standard exce
A fuzzy approach for modelling radionuclide in lake system.
Desai, H K; Christian, R A; Banerjee, J; Patra, A K
2013-10-01
Radioactive liquid waste is generated during operation and maintenance of Pressurised Heavy Water Reactors (PHWRs). Generally low level liquid waste is diluted and then discharged into the near by water-body through blowdown water discharge line as per the standard waste management practice. The effluents from nuclear installations are treated adequately and then released in a controlled manner under strict compliance of discharge criteria. An attempt was made to predict the concentration of (3)H released from Kakrapar Atomic Power Station at Ratania Regulator, about 2.5 km away from the discharge point, where human exposure is expected. Scarcity of data and complex geometry of the lake prompted the use of Heuristic approach. Under this condition, Fuzzy rule based approach was adopted to develop a model, which could predict (3)H concentration at Ratania Regulator. Three hundred data were generated for developing the fuzzy rules, in which input parameters were water flow from lake and (3)H concentration at discharge point. The Output was (3)H concentration at Ratania Regulator. These data points were generated by multiple regression analysis of the original data. Again by using same methodology hundred data were generated for the validation of the model, which were compared against the predicted output generated by using Fuzzy Rule based approach. Root Mean Square Error of the model came out to be 1.95, which showed good agreement by Fuzzy model of natural ecosystem. Copyright © 2013 Elsevier Ltd. All rights reserved.
MARK DE REUVER; HARRY BOUWMAN; TIMBER HAAKER
2013-01-01
Literature on business models deals extensively with how to design new business models, but hardly with how to make the transition from an existing to a newly designed business model. The transition to a new business model raises several practical and strategic issues, such as how to replace an existing value proposition with a new one, when to acquire new resources and capabilities, and when to start new partnerships. In this paper, we coin the term business model roadmapping as an approach ...
Ocean Data Assimilation in the Gulf of Mexico Using 3D VAR Approach - Preliminary Results
Paturi, S.; Garraffo, Z. D.; Cummings, J. A.; Rivin, I.; Mehra, A.; Kim, H. C.
2016-12-01
Approaches to ocean data assimilation vary widely, both in terms of the sophistication of the method and the observations assimilated.A three-dimensional variational (3DVAR) data assimilation system, part of the Navy Coupled Ocean Data Assimilation (NCODA) system developed at Navy Research Laboratory (NRL), is used for assimilating Sea Surface Temperature (SST) and Sea Surface Height (SSH) in the Gulf of Mexico (GoM). The NCODA 3DVAR produces simultaneous analyses of temperature, salinity, and vector velocity and uses all possible sources of ocean data observations.The Hybrid Coordinate Ocean Model (HYCOM) is used for the simulations, at 1/25o grid resolution for July 2011 period. After successful implementation of NCODA 3DVAR in the GoM, the system will be extended to the global ocean with the intent of making it operational.
Blade element momentum modeling of inflow with shear in comparison with advanced model results
DEFF Research Database (Denmark)
Aagaard Madsen, Helge; Riziotis, V.; Zahle, Frederik
2012-01-01
shear is present in the inflow. This gives guidance to how the BEM modeling of shear should be implemented. Another result from the advanced vortex model computations is a clear indication of influence of the ground, and the general tendency is a speed up effect of the flow through the rotor giving...
Anthropomorphic Coding of Speech and Audio: A Model Inversion Approach
Directory of Open Access Journals (Sweden)
W. Bastiaan Kleijn
2005-06-01
Full Text Available Auditory modeling is a well-established methodology that provides insight into human perception and that facilitates the extraction of signal features that are most relevant to the listener. The aim of this paper is to provide a tutorial on perceptual speech and audio coding using an invertible auditory model. In this approach, the audio signal is converted into an auditory representation using an invertible auditory model. The auditory representation is quantized and coded. Upon decoding, it is then transformed back into the acoustic domain. This transformation converts a complex distortion criterion into a simple one, thus facilitating quantization with low complexity. We briefly review past work on auditory models and describe in more detail the components of our invertible model and its inversion procedure, that is, the method to reconstruct the signal from the output of the auditory model. We summarize attempts to use the auditory representation for low-bit-rate coding. Our approach also allows the exploitation of the inherent redundancy of the human auditory system for the purpose of multiple description (joint source-channel coding.
Regionalization of climate model results for the North Sea
Energy Technology Data Exchange (ETDEWEB)
Kauker, F.
1999-07-01
A dynamical downscaling is presented that allows an estimation of potential effects of climate change on the North Sea. Therefore, the ocean general circulation model OPYC is adapted for application on a shelf by adding a lateral boundary formulation and a tide model. In this set-up the model is forced, first, with data from the ECMWF reanalysis for model validation and the study of the natural variability, and, second, with data from climate change experiments to estimate the effects of climate change on the North Sea. (orig.)
Integrated design approach of the pebble bed modular using models
International Nuclear Information System (INIS)
Venter, P.J.
2005-01-01
The Pebble Bed Modular Reactor (PBMR) is the first pebble bed reactor that will be utilised in a high temperature direct Brayton cycle configuration. This implies that there are a number of unique features in the PBMR that extend from the German experience base. One of the challenges in the design of the PBMR is managing the integrated design process between the designers, the physicists and the analysts. This integrated design process is managed through model-based development work. Three-dimensional CAD models are constructed of the components and parts in the reactor. From the CAD models, CFD models, neutronic models, shielding models, FEM models and other thermodynamic models are derived. These models range from very simple models to extremely detailed and complex models. The models are used in legacy software as well as commercial off-the-shelf software. The different models are also used in code-to-code comparisons to verify the results. This paper will briefly discuss the different models and the interaction between the models, showing the iterative design process that is used in the development of the reactor at PBMR. (author)
Process-Product Approach to Writing: the Effect of Model Essays on EFL Learners’ Writing Accuracy
Directory of Open Access Journals (Sweden)
Parastou Gholami Pasand
2013-01-01
Full Text Available Writing is one the most important skills in learning a foreign language. The significance of being able to write in a second or foreign language has become clearer nowadays. Accordingly, different approaches to writing such as product approach, process approach and more recently process-product approach came into existence and they have been the concern of SL/FL researchers. The aim of this study is to answer the question that whether the use of an incomplete model text in process-product approach to writing and asking the learners to complete the text rather than copying it can have a positive impact on EFL learners’ accuracy in writing. After training a number of EFL learners on using process approach, we held a two-session writing class. In the first session students wrote in the process approach, and in the second one they were given a model text to continue in the process-product approach. The writing performance of the students in these two sessions was compared in term of accuracy. Based on the students’ writing performance, we came to the conclusion that completing the model text in process-product writing can have a rather positive influence in some aspects of their writing accuracy such as punctuation, capitalization, spelling, subject-verb agreement, tense, the use of connectors, using correct pronouns and possessives. Also the results of the paired t-test indicate that using a model text to continue increased students’ writing accuracy.
Wang, S.; Peters-Lidard, C. D.; Mocko, D. M.; Kumar, S.; Nearing, G. S.; Arsenault, K. R.; Geiger, J. V.
2014-12-01
interfaces, the general model interface and five case studies, including a regression model, Noah-MP, FASST, SAC-HTET/SNOW-17, and FLake. These different models vary in complexity with software structure. Also, we will describe how these complexities were overcome through using this approach and results of model benchmarks within LIS.
A Novel Approach to Implement Takagi-Sugeno Fuzzy Models.
Chang, Chia-Wen; Tao, Chin-Wang
2017-09-01
This paper proposes new algorithms based on the fuzzy c-regressing model algorithm for Takagi-Sugeno (T-S) fuzzy modeling of the complex nonlinear systems. A fuzzy c-regression state model (FCRSM) algorithm is a T-S fuzzy model in which the functional antecedent and the state-space-model-type consequent are considered with the available input-output data. The antecedent and consequent forms of the proposed FCRSM consists mainly of two advantages: one is that the FCRSM has low computation load due to only one input variable is considered in the antecedent part; another is that the unknown system can be modeled to not only the polynomial form but also the state-space form. Moreover, the FCRSM can be extended to FCRSM-ND and FCRSM-Free algorithms. An algorithm FCRSM-ND is presented to find the T-S fuzzy state-space model of the nonlinear system when the input-output data cannot be precollected and an assumed effective controller is available. In the practical applications, the mathematical model of controller may be hard to be obtained. In this case, an online tuning algorithm, FCRSM-FREE, is designed such that the parameters of a T-S fuzzy controller and the T-S fuzzy state model of an unknown system can be online tuned simultaneously. Four numerical simulations are given to demonstrate the effectiveness of the proposed approach.
A Composite Modelling Approach to Decision Support by the Use of the CBA-DK Model
DEFF Research Database (Denmark)
Barfod, Michael Bruhn; Salling, Kim Bang; Leleur, Steen
2007-01-01
This paper presents a decision support system for assessment of transport infrastructure projects. The composite modelling approach, COSIMA, combines a cost-benefit analysis by use of the CBA-DK model with multi-criteria analysis applying the AHP and SMARTER techniques. The modelling uncertaintie...
Effect of geometry of rice kernels on drying modeling results
Geometry of rice grain is commonly represented by sphere, spheroid or ellipsoid shapes in the drying models. Models using simpler shapes are easy to solve mathematically, however, deviation from the true grain shape might lead to large errors in predictions of drying characteristics such as, moistur...
Spinal cord stimulation: modeling results and clinical data
Struijk, Johannes J.; Struijk, J.J.; Holsheimer, J.; Barolat, Giancarlo; He, Jiping
1992-01-01
The potential distribution in volume couductor models of the spinal cord at cervical, midthoracic and lowthoracic levels, due to epidural stimulation, was calculated. Treshold stimuli of modeled myelhated dorsal column and dorsal root fibers were calculated and were compared with perception
Quark cluster model of nuclei and lepton scattering results
International Nuclear Information System (INIS)
Vary, J.P.; Iowa State Univ. of Science and Technology, Ames
1984-01-01
A review of the quark cluster model (QCM) of nuclei is presented along with applications to deep inelastic lepton scattering and elastic lepton scattering experiments. In addition a sample comparison is made with high momentum transfer (p, π) data. The QCM prediction for the ratio of nuclear structure functions in the x > 1 domain is discussed as a critical test of the model
How to: understanding SWAT model uncertainty relative to measured results
Watershed models are being relied upon to contribute to most policy-making decisions of watershed management, and the demand for an accurate accounting of complete model uncertainty is rising. Generalized likelihood uncertainty estimation (GLUE) is a widely used method for quantifying uncertainty i...
Directory of Open Access Journals (Sweden)
Salabura Piotr
2017-01-01
Full Text Available HADES experiment at GSI is the only high precision experiment probing nuclear matter in the beam energy range of a few AGeV. Pion, proton and ion beams are used to study rare dielectron and strangeness probes to diagnose properties of strongly interacting matter in this energy regime. Selected results from p + A and A + A collisions are presented and discussed.
Comparative Results on 3D Navigation of Quadrotor using two Nonlinear Model based Controllers
Bouzid, Y.; Siguerdidjane, H.; Bestaoui, Y.
2017-01-01
Recently the quadrotors are being increasingly employed in both military and civilian areas where a broad range of nonlinear flight control techniques are successfully implemented. With this advancement, it has become necessary to investigate the efficiency of these flight controllers by studying theirs features and compare their performance. In this paper, the control of Unmanned Aerial Vehicle (UAV) quadrotor, using two different approaches, is presented. The first controller is Nonlinear PID (NLPID) whilst the second one is Nonlinear Internal Model Control (NLIMC) that are used for the stabilization as well as for the 3D trajectory tracking. The numerical simulations have shown satisfactory results using nominal system model or disturbed model for both of them. The obtained results are analyzed with respect to several criteria for the sake of comparison.
The place of quantitative energy models in a prospective approach
International Nuclear Information System (INIS)
Taverdet-Popiolek, N.
2009-01-01
Futurology above all depends on having the right mind set. Gaston Berger summarizes the prospective approach in 5 five main thrusts: prepare for the distant future, be open-minded (have a systems and multidisciplinary approach), carry out in-depth analyzes (draw out actors which are really determinant or the future, as well as established shed trends), take risks (imagine risky but flexible projects) and finally think about humanity, futurology being a technique at the service of man to help him build a desirable future. On the other hand, forecasting is based on quantified models so as to deduce 'conclusions' about the future. In the field of energy, models are used to draw up scenarios which allow, for instance, measuring medium or long term effects of energy policies on greenhouse gas emissions or global welfare. Scenarios are shaped by the model's inputs (parameters, sets of assumptions) and outputs. Resorting to a model or projecting by scenario is useful in a prospective approach as it ensures coherence for most of the variables that have been identified through systems analysis and that the mind on its own has difficulty to grasp. Interpretation of each scenario must be carried out in the light o the underlying framework of assumptions (the backdrop), developed during the prospective stage. When the horizon is far away (very long-term), the worlds imagined by the futurologist contain breaks (technological, behavioural and organizational) which are hard to integrate into the models. It is here that the main limit for the use of models in futurology is located. (author)
Research on teacher education programs: logic model approach.
Newton, Xiaoxia A; Poon, Rebecca C; Nunes, Nicole L; Stone, Elisa M
2013-02-01
Teacher education programs in the United States face increasing pressure to demonstrate their effectiveness through pupils' learning gains in classrooms where program graduates teach. The link between teacher candidates' learning in teacher education programs and pupils' learning in K-12 classrooms implicit in the policy discourse suggests a one-to-one correspondence. However, the logical steps leading from what teacher candidates have learned in their programs to what they are doing in classrooms that may contribute to their pupils' learning are anything but straightforward. In this paper, we argue that the logic model approach from scholarship on evaluation can enhance research on teacher education by making explicit the logical links between program processes and intended outcomes. We demonstrate the usefulness of the logic model approach through our own work on designing a longitudinal study that focuses on examining the process and impact of an undergraduate mathematics and science teacher education program. Copyright © 2012 Elsevier Ltd. All rights reserved.
Understanding complex urban systems multidisciplinary approaches to modeling
Gurr, Jens; Schmidt, J
2014-01-01
Understanding Complex Urban Systems takes as its point of departure the insight that the challenges of global urbanization and the complexity of urban systems cannot be understood – let alone ‘managed’ – by sectoral and disciplinary approaches alone. But while there has recently been significant progress in broadening and refining the methodologies for the quantitative modeling of complex urban systems, in deepening the theoretical understanding of cities as complex systems, or in illuminating the implications for urban planning, there is still a lack of well-founded conceptual thinking on the methodological foundations and the strategies of modeling urban complexity across the disciplines. Bringing together experts from the fields of urban and spatial planning, ecology, urban geography, real estate analysis, organizational cybernetics, stochastic optimization, and literary studies, as well as specialists in various systems approaches and in transdisciplinary methodologies of urban analysis, the volum...
THE EFECTIVENESS OF RHETORIC-BASED ESSAY WRITING TEACHING MODEL WITH CONTEXTUAL APPROACH
Akbar, Akbar; HP, Achmad
2015-01-01
This study aims to develop a rhetoric–based essay writing teaching model with contextual approach in order to improve essay writing skills of students in the English Department of the Education and Teaching Faculty of Lakidende University of Konawe. This instructional model was developed by using research and development. The results show that the model can improve students’ essay writing skills effectively.. It was done in experimental class of the Education and Teaching Faculty of Lakidende...
Directory of Open Access Journals (Sweden)
Bruno Dutra Roos
2015-08-01
Full Text Available ABSTRACTOBJECTIVES: To evaluate the clinical and radiographic results and complications relating to patients undergoing arthroscopic treatment for femoroacetabular impingement by means of an extracapsular approach. METHODS: Between January 2011 and March 2012, 49 patients (50 hips underwent arthroscopic treatment for femoroacetabular impingement, performed by the hip surgery team of the Orthopedic Hospital of Passo Fundo, Rio Grande do Sul. Forty patients (41 hips fulfilled all the requirements for this study. The mean follow-up was 29.1 months. The patients were assessed clinically by means of the Harris Hip score, as modified by Byrd (MHHS, the Non-Arthritic Hip score (NAHS and the internal rotation of the hip. Their hips were also evaluated radiographically, with measurement of the CE angle, dimensions of the joint space, alpha angle, neck-head index, degree of arthrosis and presence of heterotopic ossification of the hip. RESULTS: Out of the 41 hips treated, 31 (75.6% presented good or excellent clinical results. There was a mean postoperative increase of 22.1 points for the MHHS, 21.5 for the NAHS and 16.4° for the internal rotation of the hip ( p< 0.001. Regarding the radiographic evaluation, correction to normal values was observed for the alpha angle and neck-head index, with a mean postoperative decrease of 32.9° and mean increase of 0.10, respectively ( p< 0.001. CONCLUSION: Arthroscopic treatment of femoroacetabular impingement by means of an extracapsular approach presented satisfactory clinical and radiographic results over a mean follow-up of 29.1 months, with few complications.
DISCRETE LATTICE ELEMENT APPROACH FOR ROCK FAILURE MODELING
Directory of Open Access Journals (Sweden)
Mijo Nikolić
2017-01-01
Full Text Available This paper presents the ‘discrete lattice model’, or, simply, the ‘lattice model’, developed for rock failure modeling. The main difficulties in numerical modeling, namely, those related to complex crack initiations and multiple crack propagations, their coalescence under the influence of natural disorder, and heterogeneities, are overcome using the approach presented in this paper. The lattice model is constructed as an assembly of Timoshenko beams, representing the cohesive links between the grains of the material, which are described by Voronoi polygons. The kinematics of the Timoshenko beams are enhanced by the embedded strong discontinuities in their axial and transversal directions so as to provide failure modes I, II, and III. The model presented is suitable for meso-scale rock simulations. The representative numerical simulations, in both 2D and 3D settings, are provided in order to illustrate the model’s capabilities.
Computer Modeling of Violent Intent: A Content Analysis Approach
Energy Technology Data Exchange (ETDEWEB)
Sanfilippo, Antonio P.; Mcgrath, Liam R.; Bell, Eric B.
2014-01-03
We present a computational approach to modeling the intent of a communication source representing a group or an individual to engage in violent behavior. Our aim is to identify and rank aspects of radical rhetoric that are endogenously related to violent intent to predict the potential for violence as encoded in written or spoken language. We use correlations between contentious rhetoric and the propensity for violent behavior found in documents from radical terrorist and non-terrorist groups and individuals to train and evaluate models of violent intent. We then apply these models to unseen instances of linguistic behavior to detect signs of contention that have a positive correlation with violent intent factors. Of particular interest is the application of violent intent models to social media, such as Twitter, that have proved to serve as effective channels in furthering sociopolitical change.
A fuzzy approach to the Weighted Overlap Dominance model
DEFF Research Database (Denmark)
Franco de los Rios, Camilo Andres; Hougaard, Jens Leth; Nielsen, Kurt
2013-01-01
Decision support models are required to handle the various aspects of multi-criteria decision problems in order to help the individual understand its possible solutions. In this sense, such models have to be capable of aggregating and exploiting different types of measurements and evaluations...... in an interactive way, where input data can take the form of uniquely-graded or interval-valued information. Here we explore the Weighted Overlap Dominance (WOD) model from a fuzzy perspective and its outranking approach to decision support and multidimensional interval analysis. Firstly, imprecision measures...... are introduced for characterizing the type of uncertainty being expressed by intervals, examining at the same time how the WOD model handles both non-interval as well as interval data, and secondly, relevance degrees are proposed for obtaining a ranking over the alternatives. Hence, a complete methodology...
Fibroblast motility on substrates with different rigidities: modeling approach
Gracheva, Maria; Dokukina, Irina
2009-03-01
We develop a discrete model for cell locomotion on substrates with different rigidities and simulate experiments described in Lo, Wang, Dembo, Wang (2000) ``Cell movement is guided by the rigidity of the substrate'', Biophys. J. 79: 144-152. In these experiments fibroblasts were planted on a substrate with a step rigidity and showed preference for locomotion over stiffer side of the substrate when approaches the boundary between the soft and the stiff sides of the substrate. The model reproduces experimentally observed behavior of fibroblasts. In particular, we are able to show with our model how cell characteristics (such as cell length, shape, area and speed) change during cell crawling through the ``soft-stiff'' substrate boundary. Also, our model suggests the temporary increase of both cell speed and area in that very moment when cell leaves soft side of substrate.
Modeling fabrication of nuclear components: An integrative approach
Energy Technology Data Exchange (ETDEWEB)
Hench, K.W.
1996-08-01
Reduction of the nuclear weapons stockpile and the general downsizing of the nuclear weapons complex has presented challenges for Los Alamos. One is to design an optimized fabrication facility to manufacture nuclear weapon primary components in an environment of intense regulation and shrinking budgets. This dissertation presents an integrative two-stage approach to modeling the casting operation for fabrication of nuclear weapon primary components. The first stage optimizes personnel radiation exposure for the casting operation layout by modeling the operation as a facility layout problem formulated as a quadratic assignment problem. The solution procedure uses an evolutionary heuristic technique. The best solutions to the layout problem are used as input to the second stage - a simulation model that assesses the impact of competing layouts on operational performance. The focus of the simulation model is to determine the layout that minimizes personnel radiation exposures and nuclear material movement, and maximizes the utilization of capacity for finished units.
Directory of Open Access Journals (Sweden)
Jie Bao
2015-12-01
Full Text Available Effective sensitivity analysis approaches are needed to identify important parameters or factors and their uncertainties in complex Earth system models composed of multi-phase multi-component phenomena and multiple biogeophysical-biogeochemical processes. In this study, the impacts of 10 hydrologic parameters in the Community Land Model on simulations of runoff and latent heat flux are evaluated using data from a watershed. Different metrics, including residual statistics, the Nash–Sutcliffe coefficient, and log mean square error, are used as alternative measures of the deviations between the simulated and field observed values. Four sensitivity analysis (SA approaches, including analysis of variance based on the generalized linear model, generalized cross validation based on the multivariate adaptive regression splines model, standardized regression coefficients based on a linear regression model, and analysis of variance based on support vector machine, are investigated. Results suggest that these approaches show consistent measurement of the impacts of major hydrologic parameters on response variables, but with differences in the relative contributions, particularly for the secondary parameters. The convergence behaviors of the SA with respect to the number of sampling points are also examined with different combinations of input parameter sets and output response variables and their alternative metrics. This study helps identify the optimal SA approach, provides guidance for the calibration of the Community Land Model parameters to improve the model simulations of land surface fluxes, and approximates the magnitudes to be adjusted in the parameter values during parametric model optimization.
THE SIGNAL APPROACH TO MODELLING THE BALANCE OF PAYMENT CRISIS
Directory of Open Access Journals (Sweden)
O. Chernyak
2016-12-01
Full Text Available The paper considers and presents synthesis of theoretical models of balance of payment crisis and investigates the most effective ways to model the crisis in Ukraine. For mathematical formalization of balance of payment crisis, comparative analysis of the effectiveness of different calculation methods of Exchange Market Pressure Index was performed. A set of indicators that signal the growing likelihood of balance of payments crisis was defined using signal approach. With the help of minimization function thresholds indicators were selected, the crossing of which signalize increase in the probability of balance of payment crisis.
Risk Modeling Approaches in Terms of Volatility Banking Transactions
Directory of Open Access Journals (Sweden)
Angelica Cucşa (Stratulat
2016-01-01
Full Text Available The inseparability of risk and banking activity is one demonstrated ever since banking systems, the importance of the topic being presend in current life and future equally in the development of banking sector. Banking sector development is done in the context of the constraints of nature and number of existing risks and those that may arise, and serves as limiting the risk of banking activity. We intend to develop approaches to analyse risk through mathematical models by also developing a model for the Romanian capital market 10 active trading picks that will test investor reaction in controlled and uncontrolled conditions of risk aggregated with harmonised factors.