Photoconductivity of amorphous silicon-rigorous modelling
International Nuclear Information System (INIS)
Brada, P.; Schauer, F.
1991-01-01
It is our great pleasure to express our gratitude to Prof. Grigorovici, the pioneer of the exciting field of amorphous state by our modest contribution to this area. In this paper are presented the outline of the rigorous modelling program of the steady-state photoconductivity in amorphous silicon and related materials. (Author)
Rigorous classification and carbon accounting principles for low and Zero Carbon Cities
International Nuclear Information System (INIS)
Kennedy, Scott; Sgouridis, Sgouris
2011-01-01
A large number of communities, new developments, and regions aim to lower their carbon footprint and aspire to become 'zero carbon' or 'Carbon Neutral.' Yet there are neither clear definitions for the scope of emissions that such a label would address on an urban scale, nor is there a process for qualifying the carbon reduction claims. This paper addresses the question of how to define a zero carbon, Low Carbon, or Carbon Neutral urban development by proposing hierarchical emissions categories with three levels: Internal Emissions based on the geographical boundary, external emissions directly caused by core municipal activities, and internal or external emissions due to non-core activities. Each level implies a different carbon management strategy (eliminating, balancing, and minimizing, respectively) needed to meet a Net Zero Carbon designation. The trade-offs, implications, and difficulties of implementing carbon debt accounting based upon these definitions are further analyzed. - Highlights: → A gap exists in comprehensive and standardized accounting methods for urban carbon emissions. → We propose a comprehensive and rigorous City Framework for Carbon Accounting (CiFCA). → CiFCA classifies emissions hierarchically with corresponding carbon management strategies. → Adoption of CiFCA allows for meaningful comparisons of claimed performance of eco-cities.
A rigorous test for a new conceptual model for collisions
International Nuclear Information System (INIS)
Peixoto, E.M.A.; Mu-Tao, L.
1979-01-01
A rigorous theoretical foundation for the previously proposed model is formulated and applied to electron scattering by H 2 in the gas phase. An rigorous treatment of the interaction potential between the incident electron and the Hydrogen molecule is carried out to calculate Differential Cross Sections for 1 KeV electrons, using Glauber's approximation Wang's molecular wave function for the ground electronic state of H 2 . Moreover, it is shown for the first time that, when adequately done, the omission of two center terms does not adversely influence the results of molecular calculations. It is shown that the new model is far superior to the Independent Atom Model (or Independent Particle Model). The accuracy and simplicity of the new model suggest that it may be fruitfully applied to the description of other collision phenomena (e.g., in molecular beam experiments and nuclear physics). A new techniques is presented for calculations involving two center integrals within the frame work of the Glauber's approximation for scattering. (Author) [pt
Memory sparing, fast scattering formalism for rigorous diffraction modeling
Iff, W.; Kämpfe, T.; Jourlin, Y.; Tishchenko, A. V.
2017-07-01
The basics and algorithmic steps of a novel scattering formalism suited for memory sparing and fast electromagnetic calculations are presented. The formalism, called ‘S-vector algorithm’ (by analogy with the known scattering-matrix algorithm), allows the calculation of the collective scattering spectra of individual layered micro-structured scattering objects. A rigorous method of linear complexity is applied to model the scattering at individual layers; here the generalized source method (GSM) resorting to Fourier harmonics as basis functions is used as one possible method of linear complexity. The concatenation of the individual scattering events can be achieved sequentially or in parallel, both having pros and cons. The present development will largely concentrate on a consecutive approach based on the multiple reflection series. The latter will be reformulated into an implicit formalism which will be associated with an iterative solver, resulting in improved convergence. The examples will first refer to 1D grating diffraction for the sake of simplicity and intelligibility, with a final 2D application example.
Directory of Open Access Journals (Sweden)
Kelly Cristina Mucio Marques
2015-04-01
Full Text Available This study aims to assess the methodological rigor of case studies in management accounting published in Brazilian journals. The study is descriptive. The data were collected using documentary research and content analysis, and 180 papers published from 2008 to 2012 in accounting journals rated as A2, B1, and B2 that were classified as case studies were selected. Based on the literature, we established a set of 15 criteria that we expected to be identified (either explicitly or implicitly in the case studies to classify those case studies as appropriate from the standpoint of methodological rigor. These criteria were partially met by the papers analyzed. The aspects less aligned with those proposed in the literature were the following: little emphasis on justifying the need to understand phenomena in context; lack of explanation of the reason for choosing the case study strategy; the predominant use of questions that do not enable deeper analysis; many studies based on only one source of evidence; little use of data and information triangulation; little emphasis on the data collection method; a high number of cases in which confusion between case study as a research strategy and as data collection method were detected; a low number of papers reporting the method of data analysis; few reports on a study's contributions; and a minority highlighting the issues requiring further research. In conclusion, the method used to apply case studies to management accounting must be improved because few studies showed rigorous application of the procedures that this strategy requires.
Rigorous bounds on the free energy of electron-phonon models
Raedt, Hans De; Michielsen, Kristel
1997-01-01
We present a collection of rigorous upper and lower bounds to the free energy of electron-phonon models with linear electron-phonon interaction. These bounds are used to compare different variational approaches. It is shown rigorously that the ground states corresponding to the sharpest bounds do
International Nuclear Information System (INIS)
Ahmadi, A.; Meyer, M.; Rouzineau, D.; Prevost, M.; Alix, P.; Laloue, N.
2010-01-01
This paper gives the first step of the development of a rigorous multicomponent reactive separation model. Such a model is highly essential to further the optimization of acid gases removal plants (CO 2 capture, gas treating, etc.) in terms of size and energy consumption, since chemical solvents are conventionally used. Firstly, two main modelling approaches are presented: the equilibrium-based and the rate-based approaches. Secondly, an extended rate-based model with rigorous modelling methodology for diffusion-reaction phenomena is proposed. The film theory and the generalized Maxwell-Stefan equations are used in order to characterize multicomponent interactions. The complete chain of chemical reactions is taken into account. The reactions can be kinetically controlled or at chemical equilibrium, and they are considered for both liquid film and liquid bulk. Thirdly, the method of numerical resolution is described. Coupling the generalized Maxwell-Stefan equations with chemical equilibrium equations leads to a highly non-linear Differential-Algebraic Equations system known as DAE index 3. The set of equations is discretized with finite-differences as its integration by Gear method is complex. The resulting algebraic system is resolved by the Newton- Raphson method. Finally, the present model and the associated methods of numerical resolution are validated for the example of esterification of methanol. This archetype non-electrolytic system permits an interesting analysis of reaction impact on mass transfer, especially near the phase interface. The numerical resolution of the model by Newton-Raphson method gives good results in terms of calculation time and convergence. The simulations show that the impact of reactions at chemical equilibrium and that of kinetically controlled reactions with high kinetics on mass transfer is relatively similar. Moreover, the Fick's law is less adapted for multicomponent mixtures where some abnormalities such as counter
Rigorous theoretical derivation of lumped models to transmission line systems
International Nuclear Information System (INIS)
Zhao Jixiang
2012-01-01
By virtue of the negative electric parameter concept, i.e. negative lumped resistance, inductance, conductance and capacitance (N-RLGC), the lumped equivalent models of transmission line systems, including the circuit model, two-port π-network and T-network, are given. We start from the N-segment-ladder-like equivalent networks composed distributed parameters, and achieve the input impedance in the form of a continued fraction. Utilizing the continued fraction theory, the expressions of input impedance are obtained under three kinds of extreme cases, i.e. the load impedances are equal to zero, infinity and characteristic impedance, respectively. When the number of segment N is limited to infinity, they are transformed to lumped elements. Comparison between the distributed model and lumped model of transmission lines, the expression of tanh γd, which is the key term in the transmission line equations, are obtained by RLGC, furthermore, according to input admittance, admittance matrix and ABCD matrix of transmission lines, the lumped equivalent circuit models, π-networks and T-networks have been given. The models are verified in the frequency and time domain, respectively, showing that the models are accurate and efficient. (semiconductor integrated circuits)
Rigorously testing multialternative decision field theory against random utility models.
Berkowitsch, Nicolas A J; Scheibehenne, Benjamin; Rieskamp, Jörg
2014-06-01
Cognitive models of decision making aim to explain the process underlying observed choices. Here, we test a sequential sampling model of decision making, multialternative decision field theory (MDFT; Roe, Busemeyer, & Townsend, 2001), on empirical grounds and compare it against 2 established random utility models of choice: the probit and the logit model. Using a within-subject experimental design, participants in 2 studies repeatedly choose among sets of options (consumer products) described on several attributes. The results of Study 1 showed that all models predicted participants' choices equally well. In Study 2, in which the choice sets were explicitly designed to distinguish the models, MDFT had an advantage in predicting the observed choices. Study 2 further revealed the occurrence of multiple context effects within single participants, indicating an interdependent evaluation of choice options and correlations between different context effects. In sum, the results indicate that sequential sampling models can provide relevant insights into the cognitive process underlying preferential choices and thus can lead to better choice predictions. PsycINFO Database Record (c) 2014 APA, all rights reserved.
Some rigorous results on the Hopfield neural network model
International Nuclear Information System (INIS)
Koch, H.; Piasko, J.
1989-01-01
The authors analyze the thermal equilibrium distribution of 2 p mean field variables for the Hopfield model with p stored patterns, in the case where 2 p is small compared to the number of spins. In particular, they give a full description of the free energy density in the thermodynamic limit, and of the so-called symmetric solutions for the mean field equations
Semantically-Rigorous Systems Engineering Modeling Using Sysml and OWL
Jenkins, J. Steven; Rouquette, Nicolas F.
2012-01-01
The Systems Modeling Language (SysML) has found wide acceptance as a standard graphical notation for the domain of systems engineering. SysML subsets and extends the Unified Modeling Language (UML) to define conventions for expressing structural, behavioral, and analytical elements, and relationships among them. SysML-enabled modeling tools are available from multiple providers, and have been used for diverse projects in military aerospace, scientific exploration, and civil engineering. The Web Ontology Language (OWL) has found wide acceptance as a standard notation for knowledge representation. OWL-enabled modeling tools are available from multiple providers, as well as auxiliary assets such as reasoners and application programming interface libraries, etc. OWL has been applied to diverse projects in a wide array of fields. While the emphasis in SysML is on notation, SysML inherits (from UML) a semantic foundation that provides for limited reasoning and analysis. UML's partial formalization (FUML), however, does not cover the full semantics of SysML, which is a substantial impediment to developing high confidence in the soundness of any conclusions drawn therefrom. OWL, by contrast, was developed from the beginning on formal logical principles, and consequently provides strong support for verification of consistency and satisfiability, extraction of entailments, conjunctive query answering, etc. This emphasis on formal logic is counterbalanced by the absence of any graphical notation conventions in the OWL standards. Consequently, OWL has had only limited adoption in systems engineering. The complementary strengths and weaknesses of SysML and OWL motivate an interest in combining them in such a way that we can benefit from the attractive graphical notation of SysML and the formal reasoning of OWL. This paper describes an approach to achieving that combination.
Layout optimization of DRAM cells using rigorous simulation model for NTD
Jeon, Jinhyuck; Kim, Shinyoung; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Kuechler, Bernd; Zimmermann, Rainer; Muelders, Thomas; Klostermann, Ulrich; Schmoeller, Thomas; Do, Mun-hoe; Choi, Jung-Hoe
2014-03-01
DRAM chip space is mainly determined by the size of the memory cell array patterns which consist of periodic memory cell features and edges of the periodic array. Resolution Enhancement Techniques (RET) are used to optimize the periodic pattern process performance. Computational Lithography such as source mask optimization (SMO) to find the optimal off axis illumination and optical proximity correction (OPC) combined with model based SRAF placement are applied to print patterns on target. For 20nm Memory Cell optimization we see challenges that demand additional tool competence for layout optimization. The first challenge is a memory core pattern of brick-wall type with a k1 of 0.28, so it allows only two spectral beams to interfere. We will show how to analytically derive the only valid geometrically limited source. Another consequence of two-beam interference limitation is a "super stable" core pattern, with the advantage of high depth of focus (DoF) but also low sensitivity to proximity corrections or changes of contact aspect ratio. This makes an array edge correction very difficult. The edge can be the most critical pattern since it forms the transition from the very stable regime of periodic patterns to non-periodic periphery, so it combines the most critical pitch and highest susceptibility to defocus. Above challenge makes the layout correction to a complex optimization task demanding a layout optimization that finds a solution with optimal process stability taking into account DoF, exposure dose latitude (EL), mask error enhancement factor (MEEF) and mask manufacturability constraints. This can only be achieved by simultaneously considering all criteria while placing and sizing SRAFs and main mask features. The second challenge is the use of a negative tone development (NTD) type resist, which has a strong resist effect and is difficult to characterize experimentally due to negative resist profile taper angles that perturb CD at bottom characterization by
International Nuclear Information System (INIS)
García-Valenzuela, A; Contreras-Tello, H; Márquez-Islas, R; Sánchez-Pérez, C
2013-01-01
We derive an optical model for the light intensity distribution around the critical angle in a standard Abbe refractometer when used on absorbing homogenous fluids. The model is developed using rigorous electromagnetic optics. The obtained formula is very simple and can be used suitably in the analysis and design of optical sensors relying on Abbe type refractometry.
The effect of temperature on the mechanical aspects of rigor mortis in a liquid paraffin model.
Ozawa, Masayoshi; Iwadate, Kimiharu; Matsumoto, Sari; Asakura, Kumiko; Ochiai, Eriko; Maebashi, Kyoko
2013-11-01
Rigor mortis is an important phenomenon to estimate the postmortem interval in forensic medicine. Rigor mortis is affected by temperature. We measured stiffness of rat muscles using a liquid paraffin model to monitor the mechanical aspects of rigor mortis at five temperatures (37, 25, 10, 5 and 0°C). At 37, 25 and 10°C, the progression of stiffness was slower in cooler conditions. At 5 and 0°C, the muscle stiffness increased immediately after the muscles were soaked in cooled liquid paraffin and then muscles gradually became rigid without going through a relaxed state. This phenomenon suggests that it is important to be careful when estimating the postmortem interval in cold seasons. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
International Nuclear Information System (INIS)
Adam, G.; Adam, S.
2007-01-01
The Green function (GF) equation of motion technique for solving the effective two-band Hubbard model of high-T c superconductivity in cuprates rests on the Hubbard operator (HO) algebra. We show that, if we take into account the invariance to translations and spin reversal, the HO algebra results in invariance properties of several specific correlation functions. The use of these properties allows rigorous derivation and simplification of the expressions of the frequency matrix (FM) and of the generalized mean-field approximation (GMFA) Green functions (GFs) of the model. For the normal singlet hopping and anomalous exchange pairing correlation functions which enter the FM and GMFA-GFs, the use of spectral representations allows the identification and elimination of exponentially small quantities. This procedure secures the reduction of the correlation order to the GMFA-GF expressions
International Nuclear Information System (INIS)
Kim, Chang-Bae; Krommes, J.A.
1988-08-01
The work of Krommes and Smith on rigorous upper bounds for the turbulent transport of a passively advected scalar [/ital Ann. Phys./ 177:246 (1987)] is extended in two directions: (1) For their ''reference model,'' improved upper bounds are obtained by utilizing more sophisticated two-time constraints which include the effects of cross-correlations up to fourth order. Numerical solutions of the model stochastic differential equation are also obtained; they show that the new bounds compare quite favorably with the exact results, even at large Reynolds and Kubo numbers. (2) The theory is extended to take account of a finite spatial autocorrelation length L/sub c/. As a reasonably generic example, the problem of particle transport due to statistically specified stochastic magnetic fields in a collisionless turbulent plasma is revisited. A bound is obtained which reduces for small L/sub c/ to the quasilinear limit and for large L/sub c/ to the strong turbulence limit, and which provides a reasonable and rigorous interpolation for intermediate values of L/sub c/. 18 refs., 6 figs
Rigorous spin-spin correlation function of Ising model on a special kind of Sierpinski Carpets
International Nuclear Information System (INIS)
Yang, Z.R.
1993-10-01
We have exactly calculated the rigorous spin-spin correlation function of Ising model on a special kind of Sierpinski Carpets (SC's) by means of graph expansion and a combinatorial approach and investigated the asymptotic behaviour in the limit of long distance. The result show there is no long range correlation between spins at any finite temperature which indicates no existence of phase transition and thus finally confirms the conclusion produced by the renormalization group method and other physical arguments. (author). 7 refs, 6 figs
Parent Management Training-Oregon Model: Adapting Intervention with Rigorous Research.
Forgatch, Marion S; Kjøbli, John
2016-09-01
Parent Management Training-Oregon Model (PMTO(®) ) is a set of theory-based parenting programs with status as evidence-based treatments. PMTO has been rigorously tested in efficacy and effectiveness trials in different contexts, cultures, and formats. Parents, the presumed agents of change, learn core parenting practices, specifically skill encouragement, limit setting, monitoring/supervision, interpersonal problem solving, and positive involvement. The intervention effectively prevents and ameliorates children's behavior problems by replacing coercive interactions with positive parenting practices. Delivery format includes sessions with individual families in agencies or families' homes, parent groups, and web-based and telehealth communication. Mediational models have tested parenting practices as mechanisms of change for children's behavior and found support for the theory underlying PMTO programs. Moderating effects include children's age, maternal depression, and social disadvantage. The Norwegian PMTO implementation is presented as an example of how PMTO has been tailored to reach diverse populations as delivered by multiple systems of care throughout the nation. An implementation and research center in Oslo provides infrastructure and promotes collaboration between practitioners and researchers to conduct rigorous intervention research. Although evidence-based and tested within a wide array of contexts and populations, PMTO must continue to adapt to an ever-changing world. © 2016 Family Process Institute.
Directory of Open Access Journals (Sweden)
Spiros Pagiatakis
2009-10-01
Full Text Available In this paper, we examine the effect of changing the temperature points on MEMS-based inertial sensor random error. We collect static data under different temperature points using a MEMS-based inertial sensor mounted inside a thermal chamber. Rigorous stochastic models, namely Autoregressive-based Gauss-Markov (AR-based GM models are developed to describe the random error behaviour. The proposed AR-based GM model is initially applied to short stationary inertial data to develop the stochastic model parameters (correlation times. It is shown that the stochastic model parameters of a MEMS-based inertial unit, namely the ADIS16364, are temperature dependent. In addition, field kinematic test data collected at about 17 °C are used to test the performance of the stochastic models at different temperature points in the filtering stage using Unscented Kalman Filter (UKF. It is shown that the stochastic model developed at 20 °C provides a more accurate inertial navigation solution than the ones obtained from the stochastic models developed at −40 °C, −20 °C, 0 °C, +40 °C, and +60 °C. The temperature dependence of the stochastic model is significant and should be considered at all times to obtain optimal navigation solution for MEMS-based INS/GPS integration.
El-Diasty, Mohammed; Pagiatakis, Spiros
2009-01-01
In this paper, we examine the effect of changing the temperature points on MEMS-based inertial sensor random error. We collect static data under different temperature points using a MEMS-based inertial sensor mounted inside a thermal chamber. Rigorous stochastic models, namely Autoregressive-based Gauss-Markov (AR-based GM) models are developed to describe the random error behaviour. The proposed AR-based GM model is initially applied to short stationary inertial data to develop the stochastic model parameters (correlation times). It is shown that the stochastic model parameters of a MEMS-based inertial unit, namely the ADIS16364, are temperature dependent. In addition, field kinematic test data collected at about 17 °C are used to test the performance of the stochastic models at different temperature points in the filtering stage using Unscented Kalman Filter (UKF). It is shown that the stochastic model developed at 20 °C provides a more accurate inertial navigation solution than the ones obtained from the stochastic models developed at -40 °C, -20 °C, 0 °C, +40 °C, and +60 °C. The temperature dependence of the stochastic model is significant and should be considered at all times to obtain optimal navigation solution for MEMS-based INS/GPS integration.
A Rigorous Investigation on the Ground State of the Penson-Kolb Model
Yang, Kai-Hua; Tian, Guang-Shan; Han, Ru-Qi
2003-05-01
By using either numerical calculations or analytical methods, such as the bosonization technique, the ground state of the Penson-Kolb model has been previously studied by several groups. Some physicists argued that, as far as the existence of superconductivity in this model is concerned, it is canonically equivalent to the negative-U Hubbard model. However, others did not agree. In the present paper, we shall investigate this model by an independent and rigorous approach. We show that the ground state of the Penson-Kolb model is nondegenerate and has a nonvanishing overlap with the ground state of the negative-U Hubbard model. Furthermore, we also show that the ground states of both the models have the same good quantum numbers and may have superconducting long-range order at the same momentum q = 0. Our results support the equivalence between these models. The project partially supported by the Special Funds for Major State Basic Research Projects (G20000365) and National Natural Science Foundation of China under Grant No. 10174002
Hamid, H.
2018-01-01
The purpose of this study is to analyze an improvement of students’ mathematical critical thinking (CT) ability in Real Analysis course by using Rigorous Teaching and Learning (RTL) model with informal argument. In addition, this research also attempted to understand students’ CT on their initial mathematical ability (IMA). This study was conducted at a private university in academic year 2015/2016. The study employed the quasi-experimental method with pretest-posttest control group design. The participants of the study were 83 students in which 43 students were in the experimental group and 40 students were in the control group. The finding of the study showed that students in experimental group outperformed students in control group on mathematical CT ability based on their IMA (high, medium, low) in learning Real Analysis. In addition, based on medium IMA the improvement of mathematical CT ability of students who were exposed to RTL model with informal argument was greater than that of students who were exposed to CI (conventional instruction). There was also no effect of interaction between RTL model and CI model with both (high, medium, and low) IMA increased mathematical CT ability. Finally, based on (high, medium, and low) IMA there was a significant improvement in the achievement of all indicators of mathematical CT ability of students who were exposed to RTL model with informal argument than that of students who were exposed to CI.
Revisiting the constant growth angle: Estimation and verification via rigorous thermal modeling
Virozub, Alexander; Rasin, Igal G.; Brandon, Simon
2008-12-01
Methods for estimating growth angle ( θgr) values, based on the a posteriori analysis of directionally solidified material (e.g. drops) often involve assumptions of negligible gravitational effects as well as a planar solid/liquid interface during solidification. We relax both of these assumptions when using experimental drop shapes from the literature to estimate the relevant growth angles at the initial stages of solidification. Assumed to be constant, we use these values as input into a rigorous heat transfer and solidification model of the growth process. This model, which is shown to reproduce the experimental shape of a solidified sessile water drop using the literature value of θgr=0∘, yields excellent agreement with experimental profiles using our estimated values for silicon ( θgr=10∘) and germanium ( θgr=14.3∘) solidifying on an isotropic crystalline surface. The effect of gravity on the solidified drop shape is found to be significant in the case of germanium, suggesting that gravity should either be included in the analysis or that care should be taken that the relevant Bond number is truly small enough in each measurement. The planar solidification interface assumption is found to be unjustified. Although this issue is important when simulating the inflection point in the profile of the solidified water drop, there are indications that solidified drop shapes (at least in the case of silicon) may be fairly insensitive to the shape of this interface.
Chen, Xinzhong; Lo, Chiu Fan Bowen; Zheng, William; Hu, Hai; Dai, Qing; Liu, Mengkun
2017-11-01
Over the last decade, scattering-type scanning near-field optical microscopy and spectroscopy have been widely used in nano-photonics and material research due to their fine spatial resolution and broad spectral range. A number of simplified analytical models have been proposed to quantitatively understand the tip-scattered near-field signal. However, a rigorous interpretation of the experimental results is still lacking at this stage. Numerical modelings, on the other hand, are mostly done by simulating the local electric field slightly above the sample surface, which only qualitatively represents the near-field signal rendered by the tip-sample interaction. In this work, we performed a more comprehensive numerical simulation which is based on realistic experimental parameters and signal extraction procedures. By directly comparing to the experiments as well as other simulation efforts, our methods offer a more accurate quantitative description of the near-field signal, paving the way for future studies of complex systems at the nanoscale.
Diffraction-based overlay measurement on dedicated mark using rigorous modeling method
Lu, Hailiang; Wang, Fan; Zhang, Qingyun; Chen, Yonghui; Zhou, Chang
2012-03-01
Diffraction Based Overlay (DBO) is widely evaluated by numerous authors, results show DBO can provide better performance than Imaging Based Overlay (IBO). However, DBO has its own problems. As well known, Modeling based DBO (mDBO) faces challenges of low measurement sensitivity and crosstalk between various structure parameters, which may result in poor accuracy and precision. Meanwhile, main obstacle encountered by empirical DBO (eDBO) is that a few pads must be employed to gain sufficient information on overlay-induced diffraction signature variations, which consumes more wafer space and costs more measuring time. Also, eDBO may suffer from mark profile asymmetry caused by processes. In this paper, we propose an alternative DBO technology that employs a dedicated overlay mark and takes a rigorous modeling approach. This technology needs only two or three pads for each direction, which is economic and time saving. While overlay measurement error induced by mark profile asymmetry being reduced, this technology is expected to be as accurate and precise as scatterometry technologies.
A Generic Model for Relative Adjustment Between Optical Sensors Using Rigorous Orbit Mechanics
Directory of Open Access Journals (Sweden)
B. Islam
2008-06-01
Full Text Available The classical calibration or space resection is the fundamental task in photogrammetry. The lack of sufficient knowledge of interior and exterior orientation parameters lead to unreliable results in the photogrammetric process. One of the earliest in approaches using in photogrammetry was the plumb line calibration method. This method is suitable to recover the radial and decentering lens distortion coefficients, while the remaining interior(focal length and principal point coordinates and exterior orientation parameters have to be determined by a complimentary method. As the lens distortion remains very less it not considered as the interior orientation parameters, in the present rigorous sensor model. There are several other available methods based on the photogrammetric collinearity equations, which consider the determination of exterior orientation parameters, with no mention to the simultaneous determination of inner orientation parameters. Normal space resection methods solve the problem using control points, whose coordinates are known both in image and object reference systems. The non-linearity of the model and the problems, in point location in digital images and identifying the maximum GPS measured control points are the main drawbacks of the classical approaches. This paper addresses mathematical model based on the fundamental assumption of collineariy of three points of two Along-Track Stereo imagery sensors and independent object point. Assuming this condition it is possible to extract the exterior orientation (EO parameters for a long strip and single image together, without and with using the control points. Moreover, after extracting the EO parameters the accuracy for satellite data products are compared in with using single and with no control points.
Directory of Open Access Journals (Sweden)
Kun Hu
2016-09-01
Full Text Available High precision geometric rectification of High Resolution Satellite Imagery (HRSI is the basis of digital mapping and Three-Dimensional (3D modeling. Taking advantage of line features as basic geometric control conditions instead of control points, the Line-Based Transformation Model (LBTM provides a practical and efficient way of image rectification. It is competent to build the mathematical relationship between image space and the corresponding object space accurately, while it reduces the workloads of ground control and feature recognition dramatically. Based on generalization and the analysis of existing LBTMs, a novel rigorous LBTM is proposed in this paper, which can further eliminate the geometric deformation caused by sensor inclination and terrain variation. This improved nonlinear LBTM is constructed based on a generalized point strategy and resolved by least squares overall adjustment. Geo-positioning accuracy experiments with IKONOS, GeoEye-1 and ZiYuan-3 satellite imagery are performed to compare rigorous LBTM with other relevant line-based and point-based transformation models. Both theoretic analysis and experimental results demonstrate that the rigorous LBTM is more accurate and reliable without adding extra ground control. The geo-positioning accuracy of satellite imagery rectified by rigorous LBTM can reach about one pixel with eight control lines and can be further improved by optimizing the horizontal and vertical distribution of control lines.
Scientific rigor through videogames.
Treuille, Adrien; Das, Rhiju
2014-11-01
Hypothesis-driven experimentation - the scientific method - can be subverted by fraud, irreproducibility, and lack of rigorous predictive tests. A robust solution to these problems may be the 'massive open laboratory' model, recently embodied in the internet-scale videogame EteRNA. Deploying similar platforms throughout biology could enforce the scientific method more broadly. Copyright © 2014 Elsevier Ltd. All rights reserved.
Modelling in Accounting. Theoretical and Practical Dimensions
Directory of Open Access Journals (Sweden)
Teresa Szot-Gabryś
2010-10-01
Full Text Available Accounting in the theoretical approach is a scientific discipline based on specific paradigms. In the practical aspect, accounting manifests itself through the introduction of a system for measurement of economic quantities which operates in a particular business entity. A characteristic of accounting is its flexibility and ability of adaptation to information needs of information recipients. One of the main currents in the development of accounting theory and practice is to cover by economic measurements areas which have not been hitherto covered by any accounting system (it applies, for example, to small businesses, agricultural farms, human capital, which requires the development of an appropriate theoretical and practical model. The article illustrates the issue of modelling in accounting based on the example of an accounting model developed for small businesses, i.e. economic entities which are not obliged by law to keep accounting records.
Implementing a trustworthy cost-accounting model.
Spence, Jay; Seargeant, Dan
2015-03-01
Hospitals and health systems can develop an effective cost-accounting model and maximize the effectiveness of their cost-accounting teams by focusing on six key areas: Implementing an enhanced data model. Reconciling data efficiently. Accommodating multiple cost-modeling techniques. Improving transparency of cost allocations. Securing department manager participation. Providing essential education and training to staff members and stakeholders.
Questioning Stakeholder Legitimacy: A Philanthropic Accountability Model.
Kraeger, Patsy; Robichau, Robbie
2017-01-01
Philanthropic organizations contribute to important work that solves complex problems to strengthen communities. Many of these organizations are moving toward engaging in public policy work, in addition to funding programs. This paper raises questions of legitimacy for foundations, as well as issues of transparency and accountability in a pluralistic democracy. Measures of civic health also inform how philanthropic organizations can be accountable to stakeholders. We propose a holistic model for philanthropic accountability that combines elements of transparency and performance accountability, as well as practices associated with the American pluralistic model for democratic accountability. We argue that philanthropic institutions should seek stakeholder and public input when shaping any public policy agenda. This paper suggests a new paradigm, called philanthropic accountability that can be used for legitimacy and democratic governance of private foundations engaged in policy work. The Philanthropic Accountability Model can be empirically tested and used as a governance tool.
Understanding financial crisis through accounting models
Bezemer, D.J.
2010-01-01
This paper presents evidence that accounting (or flow-of-funds) macroeconomic models helped anticipate the credit crisis and economic recession Equilibrium models ubiquitous in mainstream policy and research did not This study traces the Intellectual pedigrees of the accounting approach as an
Simic, Vladimir
2016-06-01
As the number of end-of-life vehicles (ELVs) is estimated to increase to 79.3 million units per year by 2020 (e.g., 40 million units were generated in 2010), there is strong motivation to effectively manage this fast-growing waste flow. Intensive work on management of ELVs is necessary in order to more successfully tackle this important environmental challenge. This paper proposes an interval-parameter chance-constraint programming model for end-of-life vehicles management under rigorous environmental regulations. The proposed model can incorporate various uncertainty information in the modeling process. The complex relationships between different ELV management sub-systems are successfully addressed. Particularly, the formulated model can help identify optimal patterns of procurement from multiple sources of ELV supply, production and inventory planning in multiple vehicle recycling factories, and allocation of sorted material flows to multiple final destinations under rigorous environmental regulations. A case study is conducted in order to demonstrate the potentials and applicability of the proposed model. Various constraint-violation probability levels are examined in detail. Influences of parameter uncertainty on model solutions are thoroughly investigated. Useful solutions for the management of ELVs are obtained under different probabilities of violating system constraints. The formulated model is able to tackle a hard, uncertainty existing ELV management problem. The presented model has advantages in providing bases for determining long-term ELV management plans with desired compromises between economic efficiency of vehicle recycling system and system-reliability considerations. The results are helpful for supporting generation and improvement of ELV management plans. Copyright © 2016 Elsevier Ltd. All rights reserved.
Exactly solvable models: the way towards a rigorous treatment of phase transitions in finite systems
International Nuclear Information System (INIS)
Bugaev, K.A.
2007-01-01
The exact analytical solutions of a variety of statistical models recently obtained for finite systems are thoroughly discussed. Among them are a constrained version of the statistical multifragmentation model, the Bag Model of Gases and the Hills and Dales Model of surface partition. The finite volume analytical solutions of these models were obtained by a novel powerful mathematical method - the Laplace-Fourier transform. The Laplace-Fourier transform allows one to study the nuclear matter equation of state, the equation of state of hadronic and quark-gluon plasma and the surface entropy of large clusters on the same footing. A complete analysis of the isobaric partition singularities of these models is done for finite systems. The developed formalism allows one to exactly define the finite volume analogs of gaseous, liquid and mixed phases of these models from the first principles of statistical mechanics [ru
McCaig, Chris; Begon, Mike; Norman, Rachel; Shankland, Carron
2011-03-01
Changing scale, for example, the ability to move seamlessly from an individual-based model to a population-based model, is an important problem in many fields. In this paper, we introduce process algebra as a novel solution to this problem in the context of models of infectious disease spread. Process algebra allows us to describe a system in terms of the stochastic behaviour of individuals, and is a technique from computer science. We review the use of process algebra in biological systems, and the variety of quantitative and qualitative analysis techniques available. The analysis illustrated here solves the changing scale problem: from the individual behaviour we can rigorously derive equations to describe the mean behaviour of the system at the level of the population. The biological problem investigated is the transmission of infection, and how this relates to individual interactions.
Qian, Ma; Ma, Jie
2009-06-07
Fletcher's spherical substrate model [J. Chem. Phys. 29, 572 (1958)] is a basic model for understanding the heterogeneous nucleation phenomena in nature. However, a rigorous thermodynamic formulation of the model has been missing due to the significant complexities involved. This has not only left the classical model deficient but also likely obscured its other important features, which would otherwise have helped to better understand and control heterogeneous nucleation on spherical substrates. This work presents a rigorous thermodynamic formulation of Fletcher's model using a novel analytical approach and discusses the new perspectives derived. In particular, it is shown that the use of an intermediate variable, a selected geometrical angle or pseudocontact angle between the embryo and spherical substrate, revealed extraordinary similarities between the first derivatives of the free energy change with respect to embryo radius for nucleation on spherical and flat substrates. Enlightened by the discovery, it was found that there exists a local maximum in the difference between the equivalent contact angles for nucleation on spherical and flat substrates due to the existence of a local maximum in the difference between the shape factors for nucleation on spherical and flat substrate surfaces. This helps to understand the complexity of the heterogeneous nucleation phenomena in a practical system. Also, it was found that the unfavorable size effect occurs primarily when R<5r( *) (R: radius of substrate and r( *): critical embryo radius) and diminishes rapidly with increasing value of R/r( *) beyond R/r( *)=5. This finding provides a baseline for controlling the size effects in heterogeneous nucleation.
National Research Council Canada - National Science Library
Petkovska, Menka; Antov-Bozalo, Danijela; Nikacevic, Nikola
2006-01-01
The general objective of the project is fundamental mathematical modeling of a complex TSA system with electrothermal desorption step, with absorbers assembled of one or more cartridge-type, radial...
National Research Council Canada - National Science Library
Petkovska, Menka; Antov-Bozalo, Danijela; Markovic, Ana
2005-01-01
The general objective of the project is fundamental mathematical modeling of a complex TSA system with electrothermal desorption step, with adsorbers assembled of one or more activated carbon fiber clot (ACFC...
Directory of Open Access Journals (Sweden)
Christian Nowke
2018-06-01
Full Text Available Simulation models in many scientific fields can have non-unique solutions or unique solutions which can be difficult to find. Moreover, in evolving systems, unique final state solutions can be reached by multiple different trajectories. Neuroscience is no exception. Often, neural network models are subject to parameter fitting to obtain desirable output comparable to experimental data. Parameter fitting without sufficient constraints and a systematic exploration of the possible solution space can lead to conclusions valid only around local minima or around non-minima. To address this issue, we have developed an interactive tool for visualizing and steering parameters in neural network simulation models. In this work, we focus particularly on connectivity generation, since finding suitable connectivity configurations for neural network models constitutes a complex parameter search scenario. The development of the tool has been guided by several use cases—the tool allows researchers to steer the parameters of the connectivity generation during the simulation, thus quickly growing networks composed of multiple populations with a targeted mean activity. The flexibility of the software allows scientists to explore other connectivity and neuron variables apart from the ones presented as use cases. With this tool, we enable an interactive exploration of parameter spaces and a better understanding of neural network models and grapple with the crucial problem of non-unique network solutions and trajectories. In addition, we observe a reduction in turn around times for the assessment of these models, due to interactive visualization while the simulation is computed.
DEFF Research Database (Denmark)
Frutiger, Jerome; Abildskov, Jens; Sin, Gürkan
) weighted-least-square regression. 3) Initialization of estimation by use of linear algebra providing a first guess. 4) Sequential parameter and simultaneous GC parameter by using of 4 different minimization algorithms. 5) Thorough uncertainty analysis: a) based on asymptotic approximation of parameter...... covariance matrix b) based on boot strap method. Providing 95%-confidence intervals of parameters and predicted property. 6) Performance statistics analysis and model application. The application of the methodology is shown for a new GC model built to predict lower flammability limit (LFL) for refrigerants...... their credibility and robustness in wider industrial and scientific applications....
Modelling of functional systems of managerial accounting
Directory of Open Access Journals (Sweden)
O.V. Fomina
2017-12-01
Full Text Available The modern stage of managerial accounting development takes place under the powerful influence of managerial innovations. The article aimed at the development of integrational model of budgeting and the system of balanced indices in the system of managerial accounting that will contribute the increasing of relevance for making managerial decisions by managers of different levels management. As a result of the study the author proposed the highly pragmatical integration model of budgeting and system of the balanced indices in the system of managerial accounting, which is realized by the development of the system of gathering, consolidation, analysis, and interpretation of financial and nonfinancial information, contributes the increasing of relevance for making managerial decisions on the base of coordination and effective and purpose orientation both strategical and operative resources of an enterprise. The effective integrational process of the system components makes it possible to distribute limited resources rationally taking into account prospective purposes and strategic initiatives, to carry
International Nuclear Information System (INIS)
ZareNezhad, Bahman; Mottahedin, Mona
2012-01-01
Highlights: ► A mechanistic model for predicting gas hydrate formation kinetics is presented. ► A secondary nucleation rate model is proposed for the first time. ► Crystal–crystal collisions and crystal–impeller collisions are distinguished. ► Simultaneous determination of nucleation and growth kinetics are established. ► Important for design of gas hydrate based energy storage and CO 2 recovery systems. - Abstract: A rigorous mechanistic model for predicting gas hydrate formation crystallization kinetics is presented and the special case of CO 2 gas hydrate formation regarding CO 2 recovery and sequestration processes has been investigated by using the proposed model. A physical model for prediction of secondary nucleation rate is proposed for the first time and the formation rates of secondary nuclei by crystal–crystal collisions and crystal–impeller collisions are formulated. The objective functions for simultaneous determination of nucleation and growth kinetics are presented and a theoretical framework for predicting the dynamic behavior of gas hydrate formation is presented. Predicted time variations of CO 2 content, total number and surface area of produced hydrate crystals are in good agreement with the available experimental data. The proposed approach can have considerable application for design of gas hydrate converters regarding energy storage and CO 2 recovery processes.
Changyong, Dou; Huadong, Guo; Chunming, Han; yuquan, Liu; Xijuan, Yue; Yinghui, Zhao
2014-03-01
Raw signal simulation is a useful tool for the system design, mission planning, processing algorithm testing, and inversion algorithm design of Synthetic Aperture Radar (SAR). Due to the wide and high frequent variation of aircraft's trajectory and attitude, and the low accuracy of the Position and Orientation System (POS)'s recording data, it's difficult to quantitatively study the sensitivity of the key parameters, i.e., the baseline length and inclination, absolute phase and the orientation of the antennas etc., of the airborne Interferometric SAR (InSAR) system, resulting in challenges for its applications. Furthermore, the imprecise estimation of the installation offset between the Global Positioning System (GPS), Inertial Measurement Unit (IMU) and the InSAR antennas compounds the issue. An airborne interferometric SAR (InSAR) simulation based on the rigorous geometric model and real navigation data is proposed in this paper, providing a way for quantitatively studying the key parameters and for evaluating the effect from the parameters on the applications of airborne InSAR, as photogrammetric mapping, high-resolution Digital Elevation Model (DEM) generation, and surface deformation by Differential InSAR technology, etc. The simulation can also provide reference for the optimal design of the InSAR system and the improvement of InSAR data processing technologies such as motion compensation, imaging, image co-registration, and application parameter retrieval, etc.
International Nuclear Information System (INIS)
Changyong, Dou; Huadong, Guo; Chunming, Han; Yuquan, Liu; Xijuan, Yue; Yinghui, Zhao
2014-01-01
Raw signal simulation is a useful tool for the system design, mission planning, processing algorithm testing, and inversion algorithm design of Synthetic Aperture Radar (SAR). Due to the wide and high frequent variation of aircraft's trajectory and attitude, and the low accuracy of the Position and Orientation System (POS)'s recording data, it's difficult to quantitatively study the sensitivity of the key parameters, i.e., the baseline length and inclination, absolute phase and the orientation of the antennas etc., of the airborne Interferometric SAR (InSAR) system, resulting in challenges for its applications. Furthermore, the imprecise estimation of the installation offset between the Global Positioning System (GPS), Inertial Measurement Unit (IMU) and the InSAR antennas compounds the issue. An airborne interferometric SAR (InSAR) simulation based on the rigorous geometric model and real navigation data is proposed in this paper, providing a way for quantitatively studying the key parameters and for evaluating the effect from the parameters on the applications of airborne InSAR, as photogrammetric mapping, high-resolution Digital Elevation Model (DEM) generation, and surface deformation by Differential InSAR technology, etc. The simulation can also provide reference for the optimal design of the InSAR system and the improvement of InSAR data processing technologies such as motion compensation, imaging, image co-registration, and application parameter retrieval, etc
Media Accountability Systems: Models, proposals and outlooks
Directory of Open Access Journals (Sweden)
Luiz Martins da Silva
2007-06-01
Full Text Available This paper analyzes one of the basic actions of SOS-Imprensa, the mechanism to assure Media Accountability with the goal of proposing a synthesis of models for the Brazilian reality. The article aims to address the possibilities of creating and improving mechanisms to stimulate the democratic press process and to mark out and assure freedom of speech and personal rights with respect to the media. Based on the Press Social Responsibility Theory, the hypothesis is that the experiences analyzed (Communication Council, Press Council, Ombudsman and Readers Council are alternatives for accountability, mediation and arbitration, seeking visibility, trust and public support in favor of fairer media.
Njoku, Jonathan C.; van der Heijden, Beatrice; Inanga, Eno L.
2010-01-01
This paper aims to portray an accounting faculty expert. It is argued that neither the academic nor the professional orientation alone appears adequate in developing accounting faculty expertise. The accounting faculty expert is supposed to develop into a so-called ‘flexpert’ (Van der Heijden, 2003)
Ehret, Gerd; Bodermann, Bernd; Woehler, Martin
2007-06-01
The optical microscopy is an important instrument for dimensional characterisation or calibration of micro- and nanostructures, e.g. chrome structures on photomasks. In comparison to scanning electron microscopy (possible contamination of the sample) and atomic force microscopy (slow, risk of damage) optical microscopy is a fast and non destructive metrology method. The precise quantitative determination of the linewidth from the microscope image is, however, only possible by knowledge of the geometry of the structures and their consideration in the optical modelling. We compared two different rigorous model approaches, the Rigorous Coupled Wave Analysis (RCWA) and the Finite Elements Method (FEM) for modelling of structures with different edge angles, linewidths, line to space ratios and polarisations. The RCWA method can adapt inclined edges profiles only by a staircase approximation leading to increased modelling errors of the RCWA method. Even today's sophisticated rigorous methods still show problems with TM-polarisation. Therefore both rigorous methods are compared in terms of their convergence for TE and TM- polarisation. Beyond that also the influence of typical illumination wavelengths (365 nm, 248 nm and 193 nm) on the microscope images and their contribution to the measuring uncertainty budget will be discussed.
A simulation model for material accounting systems
International Nuclear Information System (INIS)
Coulter, C.A.; Thomas, K.E.
1987-01-01
A general-purpose model that was developed to simulate the operation of a chemical processing facility for nuclear materials has been extended to describe material measurement and accounting procedures as well. The model now provides descriptors for material balance areas, a large class of measurement instrument types and their associated measurement errors for various classes of materials, the measurement instruments themselves with their individual calibration schedules, and material balance closures. Delayed receipt of measurement results (as for off-line analytical chemistry assay), with interim use of a provisional measurement value, can be accurately represented. The simulation model can be used to estimate inventory difference variances for processing areas that do not operate at steady state, to evaluate the timeliness of measurement information, to determine process impacts of measurement requirements, and to evaluate the effectiveness of diversion-detection algorithms. Such information is usually difficult to obtain by other means. Use of the measurement simulation model is illustrated by applying it to estimate inventory difference variances for two material balance area structures of a fictitious nuclear material processing line
Modelling in Accounting. Theoretical and Practical Dimensions
Teresa Szot -Gabryś
2010-01-01
Accounting in the theoretical approach is a scientific discipline based on specific paradigms. In the practical aspect, accounting manifests itself through the introduction of a system for measurement of economic quantities which operates in a particular business entity. A characteristic of accounting is its flexibility and ability of adaptation to information needs of information recipients. One of the main currents in the development of accounting theory and practice is to cover by economic...
Püthe, Christoph; Manoj, Chandrasekharan; Kuvshinov, Alexey
2015-04-01
Electric fields induced in the conducting Earth during magnetic storms drive currents in power transmission grids, telecommunication lines or buried pipelines. These geomagnetically induced currents (GIC) can cause severe service disruptions. The prediction of GIC is thus of great importance for public and industry. A key step in the prediction of the hazard to technological systems during magnetic storms is the calculation of the geoelectric field. To address this issue for mid-latitude regions, we developed a method that involves 3-D modelling of induction processes in a heterogeneous Earth and the construction of a model of the magnetospheric source. The latter is described by low-degree spherical harmonics; its temporal evolution is derived from observatory magnetic data. Time series of the electric field can be computed for every location on Earth's surface. The actual electric field however is known to be perturbed by galvanic effects, arising from very local near-surface heterogeneities or topography, which cannot be included in the conductivity model. Galvanic effects are commonly accounted for with a real-valued time-independent distortion matrix, which linearly relates measured and computed electric fields. Using data of various magnetic storms that occurred between 2000 and 2003, we estimated distortion matrices for observatory sites onshore and on the ocean bottom. Strong correlations between modellings and measurements validate our method. The distortion matrix estimates prove to be reliable, as they are accurately reproduced for different magnetic storms. We further show that 3-D modelling is crucial for a correct separation of galvanic and inductive effects and a precise prediction of electric field time series during magnetic storms. Since the required computational resources are negligible, our approach is suitable for a real-time prediction of GIC. For this purpose, a reliable forecast of the source field, e.g. based on data from satellites
Model of accounting regulation in Lithuania
Rudžionienė, Kristina; Gipienė, Gailutė
2008-01-01
This paper analyses the regulation of accounting system in Lithuania. There are different approaches to accounting regulation. For example, the "free market" approach is against any regulation; it says that each process in the market will be in equilibrium itself. Mostly it is clear that regulation is important and useful, especially in financial accounting. It makes information in financial reports understandable and comparable in one country or different countries. There are three theories ...
An object-oriented model for ex ante accounting information
Verdaasdonk, P.J.A.
2003-01-01
Present accounting data models such as the Research-Event-Agent (REA) model merely focus on the modeling of static accounting phenomena. In this paper, it is argued that these models are not able to provide relevant ex ante accounting data for operations management decisions. These decisions require
DMFCA Model as a Possible Way to Detect Creative Accounting and Accounting Fraud in an Enterprise
Directory of Open Access Journals (Sweden)
Jindřiška Kouřilová
2013-05-01
Full Text Available The quality of reported accounting data as well as the quality and behaviour of their users influence the efficiency of an enterprise’s management. Its assessment could therefore be changed as well. To identify creative accounting and fraud, several methods and tools were used. In this paper we would like to present our proposal of the DMFCA (Detection model Material Flow Cost Accounting balance model based on environmental accounting and the MFCA (Material Flow Cost Accounting as its method. The following balance areas are included: material, financial and legislative. Using the analysis of strengths and weaknesses of the model, its possible use within a production and business company were assessed. Its possible usage to the detection of some creative accounting techniques was also assessed. The Model is developed in details for practical use and describing theoretical aspects.
Statistical mechanics rigorous results
Ruelle, David
1999-01-01
This classic book marks the beginning of an era of vigorous mathematical progress in equilibrium statistical mechanics. Its treatment of the infinite system limit has not been superseded, and the discussion of thermodynamic functions and states remains basic for more recent work. The conceptual foundation provided by the Rigorous Results remains invaluable for the study of the spectacular developments of statistical mechanics in the second half of the 20th century.
Display of the information model accounting system
Directory of Open Access Journals (Sweden)
Matija Varga
2011-12-01
Full Text Available This paper presents the accounting information system in public companies, business technology matrix and data flow diagram. The paper describes the purpose and goals of the accounting process, matrix sub-process and data class. Data flow in the accounting process and the so-called general ledger module are described in detail. Activities of the financial statements and determining the financial statements of the companies are mentioned as well. It is stated how the general ledger module should function and what characteristics it must have. Line graphs will depict indicators of the company’s business success, indebtedness and company’s efficiency coefficients based on financial balance reports, and profit and loss report.
Liu, Gang; Zhang, Jian; Bao, Jie
2016-01-01
Cost reduction on cellulase enzyme usage has been the central effort in the commercialization of fuel ethanol production from lignocellulose biomass. Therefore, establishing an accurate evaluation method on cellulase enzyme cost is crucially important to support the health development of the future biorefinery industry. Currently, the cellulase cost evaluation methods were complicated and various controversial or even conflict results were presented. To give a reliable evaluation on this important topic, a rigorous analysis based on the Aspen Plus flowsheet simulation in the commercial scale ethanol plant was proposed in this study. The minimum ethanol selling price (MESP) was used as the indicator to show the impacts of varying enzyme supply modes, enzyme prices, process parameters, as well as enzyme loading on the enzyme cost. The results reveal that the enzyme cost drives the cellulosic ethanol price below the minimum profit point when the enzyme is purchased from the current industrial enzyme market. An innovative production of cellulase enzyme such as on-site enzyme production should be explored and tested in the industrial scale to yield an economically sound enzyme supply for the future cellulosic ethanol production.
DeGeest, David Scott; Schmidt, Frank
2015-01-01
Our objective was to apply the rigorous test developed by Browne (1992) to determine whether the circumplex model fits Big Five personality data. This test has yet to be applied to personality data. Another objective was to determine whether blended items explained correlations among the Big Five traits. We used two working adult samples, the Eugene-Springfield Community Sample and the Professional Worker Career Experience Survey. Fit to the circumplex was tested via Browne's (1992) procedure. Circumplexes were graphed to identify items with loadings on multiple traits (blended items), and to determine whether removing these items changed five-factor model (FFM) trait intercorrelations. In both samples, the circumplex structure fit the FFM traits well. Each sample had items with dual-factor loadings (8 items in the first sample, 21 in the second). Removing blended items had little effect on construct-level intercorrelations among FFM traits. We conclude that rigorous tests show that the fit of personality data to the circumplex model is good. This finding means the circumplex model is competitive with the factor model in understanding the organization of personality traits. The circumplex structure also provides a theoretically and empirically sound rationale for evaluating intercorrelations among FFM traits. Even after eliminating blended items, FFM personality traits remained correlated.
The Financial Accounting Model from a System Dynamics' Perspective
Melse, Eric
2006-01-01
This paper explores the foundation of the financial accounting model. We examine the properties of the accounting equation as the principal algorithm for the design and the development of a System Dynamics model. Key to the perspective is the foundational requirement that resolves the temporal conflict that resides in a stock and flow model. Through formal analysis the accounting equation is redefined as a cybernetic model by expressing the temporal and dynamic properties of its terms. Articu...
Fielding, Michael; Inglis, Fred
2017-01-01
This contribution republishes extracts from two important articles published around 2000 concerning the punitive accountability system suffered by English primary and secondary schools. The first concerns the inspection agency Ofsted, and the second managerialism. Though they do not directly address assessment, they are highly relevant to this…
The financial accounting model from a system dynamics' perspective
Melse, E.
2006-01-01
This paper explores the foundation of the financial accounting model. We examine the properties of the accounting equation as the principal algorithm for the design and the development of a System Dynamics model. Key to the perspective is the foundational requirement that resolves the temporal
Backus, George E.
1999-01-01
The purpose of the grant was to study how prior information about the geomagnetic field can be used to interpret surface and satellite magnetic measurements, to generate quantitative descriptions of prior information that might be so used, and to use this prior information to obtain from satellite data a model of the core field with statistically justifiable error estimates. The need for prior information in geophysical inversion has long been recognized. Data sets are finite, and faithful descriptions of aspects of the earth almost always require infinite-dimensional model spaces. By themselves, the data can confine the correct earth model only to an infinite-dimensional subset of the model space. Earth properties other than direct functions of the observed data cannot be estimated from those data without prior information about the earth. Prior information is based on what the observer already knows before the data become available. Such information can be "hard" or "soft". Hard information is a belief that the real earth must lie in some known region of model space. For example, the total ohmic dissipation in the core is probably less that the total observed geothermal heat flow out of the earth's surface. (In principle, ohmic heat in the core can be recaptured to help drive the dynamo, but this effect is probably small.) "Soft" information is a probability distribution on the model space, a distribution that the observer accepts as a quantitative description of her/his beliefs about the earth. The probability distribution can be a subjective prior in the sense of Bayes or the objective result of a statistical study of previous data or relevant theories.
An ultramicroscopic study on rigor mortis.
Suzuki, T
1976-01-01
Gastrocnemius muscles taken from decapitated mice at various intervals after death and from mice killed by 2,4-dinitrophenol or mono-iodoacetic acid injection to induce rigor mortis soon after death, were observed by electron microscopy. The prominent appearance of many fine cross striations in the myofibrils (occurring about every 400 A) was considered to be characteristic of rigor mortis. These striations were caused by minute granules studded along the surfaces of both thick and thin filaments and appeared to be the bridges connecting the 2 kinds of filaments and accounted for the hardness and rigidity of the muscle.
Dolev, Danny; Függer, Matthias; Posch, Markus; Schmid, Ulrich; Steininger, Andreas; Lenzen, Christoph
2014-01-01
We present the first implementation of a distributed clock generation scheme for Systems-on-Chip that recovers from an unbounded number of arbitrary transient faults despite a large number of arbitrary permanent faults. We devise self-stabilizing hardware building blocks and a hybrid synchronous/asynchronous state machine enabling metastability-free transitions of the algorithm's states. We provide a comprehensive modeling approach that permits to prove, given correctness of the constructed low-level building blocks, the high-level properties of the synchronization algorithm (which have been established in a more abstract model). We believe this approach to be of interest in its own right, since this is the first technique permitting to mathematically verify, at manageable complexity, high-level properties of a fault-prone system in terms of its very basic components. We evaluate a prototype implementation, which has been designed in VHDL, using the Petrify tool in conjunction with some extensions, and synthesized for an Altera Cyclone FPGA. PMID:26516290
Dolev, Danny; Függer, Matthias; Posch, Markus; Schmid, Ulrich; Steininger, Andreas; Lenzen, Christoph
2014-06-01
We present the first implementation of a distributed clock generation scheme for Systems-on-Chip that recovers from an unbounded number of arbitrary transient faults despite a large number of arbitrary permanent faults. We devise self-stabilizing hardware building blocks and a hybrid synchronous/asynchronous state machine enabling metastability-free transitions of the algorithm's states. We provide a comprehensive modeling approach that permits to prove, given correctness of the constructed low-level building blocks, the high-level properties of the synchronization algorithm (which have been established in a more abstract model). We believe this approach to be of interest in its own right, since this is the first technique permitting to mathematically verify, at manageable complexity, high-level properties of a fault-prone system in terms of its very basic components. We evaluate a prototype implementation, which has been designed in VHDL, using the Petrify tool in conjunction with some extensions, and synthesized for an Altera Cyclone FPGA.
Modelling adversary actions against a nuclear material accounting system
International Nuclear Information System (INIS)
Lim, J.J.; Huebel, J.G.
1979-01-01
A typical nuclear material accounting system employing double-entry bookkeeping is described. A logic diagram is used to model the interactions of the accounting system and the adversary when he attempts to thwart it. Boolean equations are derived from the logic diagram; solution of these equations yields the accounts and records through which the adversary may disguise a SSNM theft and the collusion requirements needed to accomplish this feat. Some technical highlights of the logic diagram are also discussed
Energy Technology Data Exchange (ETDEWEB)
Chhabra, S.R.; Joachimiak, M.P.; Petzold, C.J.; Zane, G.M.; Price, M.N.; Gaucher, S.; Reveco, S.A.; Fok, V.; Johanson, A.R.; Batth, T.S.; Singer, M.; Chandonia, J.M.; Joyner, D.; Hazen, T.C.; Arkin, A.P.; Wall, J.D.; Singh, A.K.; Keasling, J.D.
2011-05-01
Protein–protein interactions offer an insight into cellular processes beyond what may be obtained by the quantitative functional genomics tools of proteomics and transcriptomics. The aforementioned tools have been extensively applied to study E. coli and other aerobes and more recently to study the stress response behavior of Desulfovibrio 5 vulgaris Hildenborough, a model anaerobe and sulfate reducer. In this paper we present the first attempt to identify protein-protein interactions in an obligate anaerobic bacterium. We used suicide vector-assisted chromosomal modification of 12 open reading frames encoded by this sulfate reducer to append an eight amino acid affinity tag to the carboxy-terminus of the chosen proteins. Three biological replicates of the 10 ‘pulled-down’ proteins were separated and analyzed using liquid chromatography-mass spectrometry. Replicate agreement ranged between 35% and 69%. An interaction network among 12 bait and 90 prey proteins was reconstructed based on 134 bait-prey interactions computationally identified to be of high confidence. We discuss the biological significance of several unique metabolic features of D. vulgaris revealed by this protein-protein interaction data 15 and protein modifications that were observed. These include the distinct role of the putative carbon monoxide-induced hydrogenase, unique electron transfer routes associated with different oxidoreductases, and the possible role of methylation in regulating sulfate reduction.
Directory of Open Access Journals (Sweden)
Swapnil R Chhabra
Full Text Available Protein-protein interactions offer an insight into cellular processes beyond what may be obtained by the quantitative functional genomics tools of proteomics and transcriptomics. The aforementioned tools have been extensively applied to study Escherichia coli and other aerobes and more recently to study the stress response behavior of Desulfovibrio vulgaris Hildenborough, a model obligate anaerobe and sulfate reducer and the subject of this study. Here we carried out affinity purification followed by mass spectrometry to reconstruct an interaction network among 12 chromosomally encoded bait and 90 prey proteins based on 134 bait-prey interactions identified to be of high confidence. Protein-protein interaction data are often plagued by the lack of adequate controls and replication analyses necessary to assess confidence in the results, including identification of potential false positives. We addressed these issues through the use of biological replication, exponentially modified protein abundance indices, results from an experimental negative control, and a statistical test to assign confidence to each putative interacting pair applicable to small interaction data studies. We discuss the biological significance of metabolic features of D. vulgaris revealed by these protein-protein interaction data and the observed protein modifications. These include the distinct role of the putative carbon monoxide-induced hydrogenase, unique electron transfer routes associated with different oxidoreductases, and the possible role of methylation in regulating sulfate reduction.
Docherty, Gary
1976-01-01
One way to bring the accounting office into the classroom is to conduct the class as a "company." Such a class is aimed at developing students' technical and managerial skills, as well as their career awareness and career goals. Performance goals, a course description, and overall objectives of the course are given and might serve as a model.…
Models and Rules of Evaluation in International Accounting
Directory of Open Access Journals (Sweden)
Niculae Feleaga
2006-04-01
Full Text Available The accounting procedures cannot be analyzed without a previous evaluation. Value is in general a very subjective issue, usually the result of a monetary evaluation made to a specific asset, group of assets or entities, or to some rendered services. Within the economic sciences, value comes from its very own deep history. In accounting, the concept of value had a late and fragile start. The term of value must not be misinterpreted as being the same thing with cost, even though value is frequently measured through costs. At the origin of the international accounting standards lays the framework for preparing, presenting and disclosing the financial statements. The framework stays as a reference matrix, as a standard of standards, as a constitution of financial accounting. According to the international framework, the financial statements use different evaluation basis: the hystorical cost, the current cost, the realisable (settlement value, the present value (the present value of cash flows. Choosing the evaluation basis and the capital maintenance concept will eventually determine the accounting evaluation model used in preparing the financial statements of a company. The multitude of accounting evaluation models differentiate themselves one from another through various relevance and reliable degrees of accounting information and therefore, accountants (the prepares of financial statements must try to equilibrate these two main qualitative characteristics of financial information.
Models and Rules of Evaluation in International Accounting
Directory of Open Access Journals (Sweden)
Liliana Feleaga
2006-06-01
Full Text Available The accounting procedures cannot be analyzed without a previous evaluation. Value is in general a very subjective issue, usually the result of a monetary evaluation made to a specific asset, group of assets or entities, or to some rendered services. Within the economic sciences, value comes from its very own deep history. In accounting, the concept of value had a late and fragile start. The term of value must not be misinterpreted as being the same thing with cost, even though value is frequently measured through costs. At the origin of the international accounting standards lays the framework for preparing, presenting and disclosing the financial statements. The framework stays as a reference matrix, as a standard of standards, as a constitution of financial accounting. According to the international framework, the financial statements use different evaluation basis: the hystorical cost, the current cost, the realisable (settlement value, the present value (the present value of cash flows. Choosing the evaluation basis and the capital maintenance concept will eventually determine the accounting evaluation model used in preparing the financial statements of a company. The multitude of accounting evaluation models differentiate themselves one from another through various relevance and reliable degrees of accounting information and therefore, accountants (the prepares of financial statements must try to equilibrate these two main qualitative characteristics of financial information.
Modelling solar cells with thermal phenomena taken into account
International Nuclear Information System (INIS)
Górecki, K; Górecki, P; Paduch, K
2014-01-01
The paper is devoted to modelling properties of solar cells. The authors' electrothermal model of such cells is described. This model takes into account the influence of temperature on its characteristics. Some results of calculations and measurements of selected solar cells are presented and discussed. The good agreement between the results of calculations and measurements was obtained, which proves the correctness of the elaborated model.
PROFESSIONAL COMPETITIVE EVOLUTION AND QUANTIFICATION MODELS IN ACCOUNTING SERVICE ELABORATION
Directory of Open Access Journals (Sweden)
Gheorghe FATACEAN
2013-12-01
Full Text Available The objective of this article consists in using an assessment framework of the accounting service elaboration. The purpose of this model is the identification and revaluation of an elite group of expert accounts from Romania, which should provide solutions to solve the most complex legal matters in the legal field, in the field of criminal, tax, civil, or commercial clauses making the object of law suits.
Individual Learning Accounts and Other Models of Financing Lifelong Learning
Schuetze, Hans G.
2007-01-01
To answer the question "Financing what?" this article distinguishes several models of lifelong learning as well as a variety of lifelong learning activities. Several financing methods are briefly reviewed, however the principal focus is on Individual Learning Accounts (ILAs) which were seen by some analysts as a promising model for…
Can An Amended Standard Model Account For Cold Dark Matter?
International Nuclear Information System (INIS)
Goldhaber, Maurice
2004-01-01
It is generally believed that one has to invoke theories beyond the Standard Model to account for cold dark matter particles. However, there may be undiscovered universal interactions that, if added to the Standard Model, would lead to new members of the three generations of elementary fermions that might be candidates for cold dark matter particles
The CARE model of social accountability: promoting cultural change.
Meili, Ryan; Ganem-Cuenca, Alejandra; Leung, Jannie Wing-sea; Zaleschuk, Donna
2011-09-01
On the 10th anniversary of Health Canada and the Association of Faculties of Medicine of Canada's publication in 2001 of Social Accountability: A Vision for Canadian Medical Schools, the authors review the progress at one Canadian medical school, the College of Medicine at the University of Saskatchewan, in developing a culture of social accountability. They review the changes that have made the medical school more socially accountable and the steps taken to make those changes possible. In response to calls for socially accountable medical schools, the College of Medicine created a Social Accountability Committee to oversee the integration of these principles into the college. The committee developed the CARE model (Clinical activity, Advocacy, Research, Education and training) as a guiding tool for social accountability initiatives toward priority health concerns and as a means of evaluation. Diverse faculty and student committees have emerged as a result and have had far-reaching impacts on the college and communities: from changes in curricula and admissions to community programming and international educational experiences. Although a systematic assessment of the CARE model is needed, early evidence shows that the most significant effects can be found in the cultural shift in the college, most notably among students. The CARE model may serve as an important example for other educational institutions in the development of health practitioners and research that is responsive to the needs of their communities.
Stochastic models in risk theory and management accounting
Brekelmans, R.C.M.
2000-01-01
This thesis deals with stochastic models in two fields: risk theory and management accounting. Firstly, two extensions of the classical risk process are analyzed. A method is developed that computes bounds of the probability of ruin for the classical risk rocess extended with a constant interest
Putrefactive rigor: apparent rigor mortis due to gas distension.
Gill, James R; Landi, Kristen
2011-09-01
Artifacts due to decomposition may cause confusion for the initial death investigator, leading to an incorrect suspicion of foul play. Putrefaction is a microorganism-driven process that results in foul odor, skin discoloration, purge, and bloating. Various decompositional gases including methane, hydrogen sulfide, carbon dioxide, and hydrogen will cause the body to bloat. We describe 3 instances of putrefactive gas distension (bloating) that produced the appearance of inappropriate rigor, so-called putrefactive rigor. These gases may distend the body to an extent that the extremities extend and lose contact with their underlying support surface. The medicolegal investigator must recognize that this is not true rigor mortis and the body was not necessarily moved after death for this gravity-defying position to occur.
Driving Strategic Risk Planning With Predictive Modelling For Managerial Accounting
DEFF Research Database (Denmark)
Nielsen, Steen; Pontoppidan, Iens Christian
for managerial accounting and shows how it can be used to determine the impact of different types of risk assessment input parameters on the variability of important outcome measures. The purpose is to: (i) point out the theoretical necessity of a stochastic risk framework; (ii) present a stochastic framework......Currently, risk management in management/managerial accounting is treated as deterministic. Although it is well-known that risk estimates are necessarily uncertain or stochastic, until recently the methodology required to handle stochastic risk-based elements appear to be impractical and too...... mathematical. The ultimate purpose of this paper is to “make the risk concept procedural and analytical” and to argue that accountants should now include stochastic risk management as a standard tool. Drawing on mathematical modelling and statistics, this paper methodically develops risk analysis approach...
Application of a predictive Bayesian model to environmental accounting.
Anex, R P; Englehardt, J D
2001-03-30
Environmental accounting techniques are intended to capture important environmental costs and benefits that are often overlooked in standard accounting practices. Environmental accounting methods themselves often ignore or inadequately represent large but highly uncertain environmental costs and costs conditioned by specific prior events. Use of a predictive Bayesian model is demonstrated for the assessment of such highly uncertain environmental and contingent costs. The predictive Bayesian approach presented generates probability distributions for the quantity of interest (rather than parameters thereof). A spreadsheet implementation of a previously proposed predictive Bayesian model, extended to represent contingent costs, is described and used to evaluate whether a firm should undertake an accelerated phase-out of its PCB containing transformers. Variability and uncertainty (due to lack of information) in transformer accident frequency and severity are assessed simultaneously using a combination of historical accident data, engineering model-based cost estimates, and subjective judgement. Model results are compared using several different risk measures. Use of the model for incorporation of environmental risk management into a company's overall risk management strategy is discussed.
Mathematical Rigor in Introductory Physics
Vandyke, Michael; Bassichis, William
2011-10-01
Calculus-based introductory physics courses intended for future engineers and physicists are often designed and taught in the same fashion as those intended for students of other disciplines. A more mathematically rigorous curriculum should be more appropriate and, ultimately, more beneficial for the student in his or her future coursework. This work investigates the effects of mathematical rigor on student understanding of introductory mechanics. Using a series of diagnostic tools in conjunction with individual student course performance, a statistical analysis will be performed to examine student learning of introductory mechanics and its relation to student understanding of the underlying calculus.
Stochastic scalar mixing models accounting for turbulent frequency multiscale fluctuations
International Nuclear Information System (INIS)
Soulard, Olivier; Sabel'nikov, Vladimir; Gorokhovski, Michael
2004-01-01
Two new scalar micromixing models accounting for a turbulent frequency scale distribution are investigated. These models were derived by Sabel'nikov and Gorokhovski [Second International Symposium on Turbulence and Shear FLow Phenomena, Royal Institute of technology (KTH), Stockholm, Sweden, June 27-29, 2001] using a multiscale extension of the classical interaction by exchange with the mean (IEM) and Langevin models. They are, respectively, called Extended IEM (EIEM) and Extended Langevin (ELM) models. The EIEM and ELM models are tested against DNS results in the case of the decay of a homogeneous scalar field in homogeneous turbulence. This comparison leads to a reformulation of the law governing the mixing frequency distribution. Finally, the asymptotic behaviour of the modeled PDF is discussed
The shift of accounting models and accounting quality: the case of Norwegian GAAP
Stenheim, Tonny; Madsen, Dag Øivind
2017-01-01
This is an Open Access journal available from http://www.virtusinterpress.org This paper investigates the change in accounting quality w hen firms shift from a revenue - oriented historical cost accounting regime as Norwegian GAAP (NGAAP) to a balance - oriented fair value accounting regime as International Financial Reporting Standards (IFRS). Previous studies have demonstrated mixed effects o n the accounting quality upon IFRS adoption. One possible reason is that the investigated domest...
Accounting for Business Models: Increasing the Visibility of Stakeholders
Directory of Open Access Journals (Sweden)
Colin Haslam
2015-01-01
Full Text Available Purpose: This paper conceptualises a firm’s business model employing stakeholder theory as a central organising element to help inform the purpose and objective(s of business model financial reporting and disclosure. Framework: Firms interact with a complex network of primary and secondary stakeholders to secure the value proposition of a firm’s business model. This value proposition is itself a complex amalgam of value creating, value capturing and value manipulating arrangements with stakeholders. From a financial accounting perspective the purpose of the value proposition for a firm’s business model is to sustain liquidity and solvency as a going concern. Findings: This article argues that stakeholder relations impact upon the financial viability of a firm’s business model value proposition. However current financial reporting by function of expenses and the central organising objectives of the accounting conceptual framework conceal firm-stakeholder relations and their impact on reported financials. Practical implications: The practical implication of our paper is that ‘Business Model’ financial reporting would require a reorientation in the accounting conceptual framework that defines the objectives and purpose of financial reporting. This reorientation would involve reporting about stakeholder relations and their impact on a firms financials not simply reporting financial information to ‘investors’. Social Implications: Business model financial reporting has the potential to be stakeholder inclusive because the numbers and narratives reported by firms in their annual financial statements will increase the visibility of stakeholder relations and how these are being managed. What is original/value of paper: This paper’s original perspective is that it argues that a firm’s business model is structured out of stakeholder relations. It presents the firm’s value proposition as the product of value creating, capturing and
Accounting for microbial habitats in modeling soil organic matter dynamics
Chenu, Claire; Garnier, Patricia; Nunan, Naoise; Pot, Valérie; Raynaud, Xavier; Vieublé, Laure; Otten, Wilfred; Falconer, Ruth; Monga, Olivier
2017-04-01
The extreme heterogeneity of soils constituents, architecture and inhabitants at the microscopic scale is increasingly recognized. Microbial communities exist and are active in a complex 3-D physical framework of mineral and organic particles defining pores of various sizes, more or less inter-connected. This results in a frequent spatial disconnection between soil carbon, energy sources and the decomposer organisms and a variety of microhabitats that are more or less suitable for microbial growth and activity. However, current biogeochemical models account for C dynamics at the macroscale (cm, m) and consider time- and spatially averaged relationships between microbial activity and soil characteristics. Different modelling approaches have intended to account for this microscale heterogeneity, based either on considering aggregates as surrogates for microbial habitats, or pores. Innovative modelling approaches are based on an explicit representation of soil structure at the fine scale, i.e. at µm to mm scales: pore architecture and their saturation with water, localization of organic resources and of microorganisms. Three recent models are presented here, that describe the heterotrophic activity of either bacteria or fungi and are based upon different strategies to represent the complex soil pore system (Mosaic, LBios and µFun). These models allow to hierarchize factors of microbial activity in soil's heterogeneous architecture. Present limits of these approaches and challenges are presented, regarding the extensive information required on soils at the microscale and to up-scale microbial functioning from the pore to the core scale.
Accounting for small scale heterogeneity in ecohydrologic watershed models
Burke, W.; Tague, C.
2017-12-01
Spatially distributed ecohydrologic models are inherently constrained by the spatial resolution of their smallest units, below which land and processes are assumed to be homogenous. At coarse scales, heterogeneity is often accounted for by computing store and fluxes of interest over a distribution of land cover types (or other sources of heterogeneity) within spatially explicit modeling units. However this approach ignores spatial organization and the lateral transfer of water and materials downslope. The challenge is to account both for the role of flow network topology and fine-scale heterogeneity. We present a new approach that defines two levels of spatial aggregation and that integrates spatially explicit network approach with a flexible representation of finer-scale aspatial heterogeneity. Critically, this solution does not simply increase the resolution of the smallest spatial unit, and so by comparison, results in improved computational efficiency. The approach is demonstrated by adapting Regional Hydro-Ecologic Simulation System (RHESSys), an ecohydrologic model widely used to simulate climate, land use, and land management impacts. We illustrate the utility of our approach by showing how the model can be used to better characterize forest thinning impacts on ecohydrology. Forest thinning is typically done at the scale of individual trees, and yet management responses of interest include impacts on watershed scale hydrology and on downslope riparian vegetation. Our approach allow us to characterize the variability in tree size/carbon reduction and water transfers between neighboring trees while still capturing hillslope to watershed scale effects, Our illustrative example demonstrates that accounting for these fine scale effects can substantially alter model estimates, in some cases shifting the impacts of thinning on downslope water availability from increases to decreases. We conclude by describing other use cases that may benefit from this approach
Accounting for household heterogeneity in general equilibrium economic growth models
International Nuclear Information System (INIS)
Melnikov, N.B.; O'Neill, B.C.; Dalton, M.G.
2012-01-01
We describe and evaluate a new method of aggregating heterogeneous households that allows for the representation of changing demographic composition in a multi-sector economic growth model. The method is based on a utility and labor supply calibration that takes into account time variations in demographic characteristics of the population. We test the method using the Population-Environment-Technology (PET) model by comparing energy and emissions projections employing the aggregate representation of households to projections representing different household types explicitly. Results show that the difference between the two approaches in terms of total demand for energy and consumption goods is negligible for a wide range of model parameters. Our approach allows the effects of population aging, urbanization, and other forms of compositional change on energy demand and CO 2 emissions to be estimated and compared in a computationally manageable manner using a representative household under assumptions and functional forms that are standard in economic growth models.
A case of instantaneous rigor?
Pirch, J; Schulz, Y; Klintschar, M
2013-09-01
The question of whether instantaneous rigor mortis (IR), the hypothetic sudden occurrence of stiffening of the muscles upon death, actually exists has been controversially debated over the last 150 years. While modern German forensic literature rejects this concept, the contemporary British literature is more willing to embrace it. We present the case of a young woman who suffered from diabetes and who was found dead in an upright standing position with back and shoulders leaned against a punchbag and a cupboard. Rigor mortis was fully established, livor mortis was strong and according to the position the body was found in. After autopsy and toxicological analysis, it was stated that death most probably occurred due to a ketoacidotic coma with markedly increased values of glucose and lactate in the cerebrospinal fluid as well as acetone in blood and urine. Whereas the position of the body is most unusual, a detailed analysis revealed that it is a stable position even without rigor mortis. Therefore, this case does not further support the controversial concept of IR.
Accelerating Biomedical Discoveries through Rigor and Transparency.
Hewitt, Judith A; Brown, Liliana L; Murphy, Stephanie J; Grieder, Franziska; Silberberg, Shai D
2017-07-01
Difficulties in reproducing published research findings have garnered a lot of press in recent years. As a funder of biomedical research, the National Institutes of Health (NIH) has taken measures to address underlying causes of low reproducibility. Extensive deliberations resulted in a policy, released in 2015, to enhance reproducibility through rigor and transparency. We briefly explain what led to the policy, describe its elements, provide examples and resources for the biomedical research community, and discuss the potential impact of the policy on translatability with a focus on research using animal models. Importantly, while increased attention to rigor and transparency may lead to an increase in the number of laboratory animals used in the near term, it will lead to more efficient and productive use of such resources in the long run. The translational value of animal studies will be improved through more rigorous assessment of experimental variables and data, leading to better assessments of the translational potential of animal models, for the benefit of the research community and society. Published by Oxford University Press on behalf of the Institute for Laboratory Animal Research 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.
Directory of Open Access Journals (Sweden)
Michael Cherry
2016-06-01
Full Text Available This paper investigates trust as it relates to the relationship between Australia’s public accountants and their SME clients. It describes the contribution of the accountancy profession to the SME market, as well as the key challenges faced by accountants and their SME clients. Following the review of prior scholarly studies, a working definition of trust as it relates to this important relationship is also developed and presented. A further consequence of prior academic work is the development of a comprehensive conceptual model to describe the determinants of trust in the Australian public accountant – SME client relationship, which requires testing via empirical studies.
International Nuclear Information System (INIS)
Kinoshita, Masahiro; Naruse, Yuji
1981-08-01
The basic equations are derived for rigorous dynamic simulation of cryogenic distillation columns for hydrogen isotope separation. The model accounts for such factors as differences in latent heat of vaporization among the six isotopic species of molecular hydrogen, decay heat of tritium, heat transfer through the column wall and nonideality of the solutions. Provision is also made for simulation of columns with multiple feeds and multiple sidestreams. (author)
Accounting for Water Insecurity in Modeling Domestic Water Demand
Galaitsis, S. E.; Huber-lee, A. T.; Vogel, R. M.; Naumova, E.
2013-12-01
Water demand management uses price elasticity estimates to predict consumer demand in relation to water pricing changes, but studies have shown that many additional factors effect water consumption. Development scholars document the need for water security, however, much of the water security literature focuses on broad policies which can influence water demand. Previous domestic water demand studies have not considered how water security can affect a population's consumption behavior. This study is the first to model the influence of water insecurity on water demand. A subjective indicator scale measuring water insecurity among consumers in the Palestinian West Bank is developed and included as a variable to explore how perceptions of control, or lack thereof, impact consumption behavior and resulting estimates of price elasticity. A multivariate regression model demonstrates the significance of a water insecurity variable for data sets encompassing disparate water access. When accounting for insecurity, the R-squaed value improves and the marginal price a household is willing to pay becomes a significant predictor for the household quantity consumption. The model denotes that, with all other variables held equal, a household will buy more water when the users are more water insecure. Though the reasons behind this trend require further study, the findings suggest broad policy implications by demonstrating that water distribution practices in scarcity conditions can promote consumer welfare and efficient water use.
Accrual based accounting implementation: An approach for modelling major decisions
Ratno Agriyanto; Abdul Rohman; Dwi Ratmono; Imam Ghozali
2016-01-01
Over the last three decades the main issues of implementation of accrual based accounting government institutions in Indonesia. Implementation of accrual based accounting in government institutions amid debate about the usefulness of accounting information for decision-making. Empirical study shows that the accrual based of accounting information on a government institution is not used for decision making. The research objective was to determine the impact of the implementation of the accrual...
Bedrijfsrisico's van de accountant en het Audit Risk Model
Wallage, Ph.; Klijnsmit, P.; Sodekamp, M.
2003-01-01
In de afgelopen jaren is het bedrijfsrisico van de controlerend accountant sterk toegenomen. De bedrijfsrisico’s van de accountant beginnen in toenemende mate een belemmering te vormen voor het aanvaarden van opdrachten. In dit artikel wordt aandacht besteed aan de wijze waarop de bedrijfsrisico’s
Accrual based accounting implementation: An approach for modelling major decisions
Directory of Open Access Journals (Sweden)
Ratno Agriyanto
2016-12-01
Full Text Available Over the last three decades the main issues of implementation of accrual based accounting government institutions in Indonesia. Implementation of accrual based accounting in government institutions amid debate about the usefulness of accounting information for decision-making. Empirical study shows that the accrual based of accounting information on a government institution is not used for decision making. The research objective was to determine the impact of the implementation of the accrual based accounting to the accrual basis of accounting information use for decision-making basis. We used the survey questionnaires. The data were processed by SEM using statistical software WarpPLS. The results showed that the implementation of the accrual based accounting in City Government Semarang has significantly positively associated with decision-making. Another important finding is the City Government officials of Semarang have personality, low tolerance of ambiguity is a negative effect on the relationship between the implementation of the accrual based accounting for decision making
Ghosh, Sreya; Preza, Chrysanthe
2015-07-01
A three-dimensional (3-D) point spread function (PSF) model for wide-field fluorescence microscopy, suitable for imaging samples with variable refractive index (RI) in multilayered media, is presented. This PSF model is a key component for accurate 3-D image restoration of thick biological samples, such as lung tissue. Microscope- and specimen-derived parameters are combined with a rigorous vectorial formulation to obtain a new PSF model that accounts for additional aberrations due to specimen RI variability. Experimental evaluation and verification of the PSF model was accomplished using images from 175-nm fluorescent beads in a controlled test sample. Fundamental experimental validation of the advantage of using improved PSFs in depth-variant restoration was accomplished by restoring experimental data from beads (6 μm in diameter) mounted in a sample with RI variation. In the investigated study, improvement in restoration accuracy in the range of 18 to 35% was observed when PSFs from the proposed model were used over restoration using PSFs from an existing model. The new PSF model was further validated by showing that its prediction compares to an experimental PSF (determined from 175-nm beads located below a thick rat lung slice) with a 42% improved accuracy over the current PSF model prediction.
A generic accounting model to support operations management decisions
Verdaasdonk, P.J.A.; Wouters, M.J.F.
2001-01-01
Information systems are generally unable to generate information about the financial consequences of operations management decisions. This is because the procedures for determining the relevant accounting information for decision support are not formalised in ways that can be implemented in
Concrete ensemble Kalman filters with rigorous catastrophic filter divergence.
Kelly, David; Majda, Andrew J; Tong, Xin T
2015-08-25
The ensemble Kalman filter and ensemble square root filters are data assimilation methods used to combine high-dimensional, nonlinear dynamical models with observed data. Ensemble methods are indispensable tools in science and engineering and have enjoyed great success in geophysical sciences, because they allow for computationally cheap low-ensemble-state approximation for extremely high-dimensional turbulent forecast models. From a theoretical perspective, the dynamical properties of these methods are poorly understood. One of the central mysteries is the numerical phenomenon known as catastrophic filter divergence, whereby ensemble-state estimates explode to machine infinity, despite the true state remaining in a bounded region. In this article we provide a breakthrough insight into the phenomenon, by introducing a simple and natural forecast model that transparently exhibits catastrophic filter divergence under all ensemble methods and a large set of initializations. For this model, catastrophic filter divergence is not an artifact of numerical instability, but rather a true dynamical property of the filter. The divergence is not only validated numerically but also proven rigorously. The model cleanly illustrates mechanisms that give rise to catastrophic divergence and confirms intuitive accounts of the phenomena given in past literature.
MAIN COORDINATES OF ACCOUNTING PROFESSION CO-OPETITIONAL MODEL
Directory of Open Access Journals (Sweden)
MARIOARA AVRAM
2012-01-01
Full Text Available The accounting profession fulfills a vital role in the development of modern economy, contributing to the thorough knowledge of business environment, the improvement of economic performance and solving some of the many problems the post-modern society is facing. Accounting profession fulfills a vital role in modern economy, contributing to a thorough knowledge of business to improve economic performance and to resolve some of the many problems facing post-modern society. Currently, the accounting profession is characterized by the expansion of information technology, internationalization of businesses and professional specialization which has made possible the creation of several professional bodies. Against this background, it becomes urgent to discover new perspectives on strategies able to maintain and increase business success, based on the simultaneous combination of the elements of cooperation and competition, which involves a new type of relation, called by the North - American literature "co-opetition".
Models and Rules of Evaluation in International Accounting
Liliana Feleaga; Niculae Feleaga
2006-01-01
The accounting procedures cannot be analyzed without a previous evaluation. Value is in general a very subjective issue, usually the result of a monetary evaluation made to a specific asset, group of assets or entities, or to some rendered services. Within the economic sciences, value comes from its very own deep history. In accounting, the concept of value had a late and fragile start. The term of value must not be misinterpreted as being the same thing with cost, even though value is freque...
Accounting for heterogeneity of public lands in hedonic property models
Charlotte Ham; Patricia A. Champ; John B. Loomis; Robin M. Reich
2012-01-01
Open space lands, national forests in particular, are usually treated as homogeneous entities in hedonic price studies. Failure to account for the heterogeneous nature of public open spaces may result in inappropriate inferences about the benefits of proximate location to such lands. In this study the hedonic price method is used to estimate the marginal values for...
Realizing rigor in the mathematics classroom
Hull, Ted H (Henry); Balka, Don S
2014-01-01
Rigor put within reach! Rigor: The Common Core has made it policy-and this first-of-its-kind guide takes math teachers and leaders through the process of making it reality. Using the Proficiency Matrix as a framework, the authors offer proven strategies and practical tools for successful implementation of the CCSS mathematical practices-with rigor as a central objective. You'll learn how to Define rigor in the context of each mathematical practice Identify and overcome potential issues, including differentiating instruction and using data
Gras, Laure-Lise; Laporte, Sébastien; Viot, Philippe; Mitton, David
2014-10-01
In models developed for impact biomechanics, muscles are usually represented with one-dimensional elements having active and passive properties. The passive properties of muscles are most often obtained from experiments performed on animal muscles, because limited data on human muscle are available. The aim of this study is thus to characterize the passive response of a human muscle in tension. Tensile tests at different strain rates (0.0045, 0.045, and 0.45 s⁻¹) were performed on 10 extensor carpi ulnaris muscles. A model composed of a nonlinear element defined with an exponential law in parallel with one or two Maxwell elements and considering basic geometrical features was proposed. The experimental results were used to identify the parameters of the model. The results for the first- and second-order model were similar. For the first-order model, the mean parameters of the exponential law are as follows: Young's modulus E (6.8 MPa) and curvature parameter α (31.6). The Maxwell element mean values are as follows: viscosity parameter η (1.2 MPa s) and relaxation time τ (0.25 s). Our results provide new data on a human muscle tested in vitro and a simple model with basic geometrical features that represent its behavior in tension under three different strain rates. This approach could be used to assess the behavior of other human muscles. © IMechE 2014.
Modelling Financial-Accounting Decisions by Means of OLAP Tools
Directory of Open Access Journals (Sweden)
Diana Elena CODREAN
2011-03-01
Full Text Available At present, one can say that a company’s good running largely depends on the information quantity and quality it relies on when making decisions. The information needed to underlie decisions and be obtained due to the existence of a high-performing information system which makes it possible for the data to be shown quickly, synthetically and truly, also providing the opportunity for complex analyses and predictions. In such circumstances, computerized accounting systems, too, have grown their complexity by means of data analyzing information solutions such as OLAP and Data Mining which help perform a multidimensional analysis of financial-accounting data, potential frauds can be detected and data hidden information can be revealed, trends for certain indicators can be set up, therefore ensuring useful information to a company’s decision making.
Classroom Talk for Rigorous Reading Comprehension Instruction
Wolf, Mikyung Kim; Crosson, Amy C.; Resnick, Lauren B.
2004-01-01
This study examined the quality of classroom talk and its relation to academic rigor in reading-comprehension lessons. Additionally, the study aimed to characterize effective questions to support rigorous reading comprehension lessons. The data for this study included 21 reading-comprehension lessons in several elementary and middle schools from…
Carrillo, J. A.; Desvillettes, L.; Fellner, K.
2009-01-01
Weak solutions of the spatially inhomogeneous (diffusive) Aizenmann-Bak model of coagulation-breakup within a bounded domain with homogeneous Neumann boundary conditions are shown to converge, in the fast reaction limit, towards local equilibria determined by their mass. Moreover, this mass is the solution of a nonlinear diffusion equation whose nonlinearity depends on the (size-dependent) diffusion coefficient. Initial data are assumed to have integrable zero order moment and square integrable first order moment in size, and finite entropy. In contrast to our previous result [5], we are able to show the convergence without assuming uniform bounds from above and below on the number density of clusters. © Taylor & Francis Group, LLC.
Carrillo, J. A.
2009-10-30
Weak solutions of the spatially inhomogeneous (diffusive) Aizenmann-Bak model of coagulation-breakup within a bounded domain with homogeneous Neumann boundary conditions are shown to converge, in the fast reaction limit, towards local equilibria determined by their mass. Moreover, this mass is the solution of a nonlinear diffusion equation whose nonlinearity depends on the (size-dependent) diffusion coefficient. Initial data are assumed to have integrable zero order moment and square integrable first order moment in size, and finite entropy. In contrast to our previous result [5], we are able to show the convergence without assuming uniform bounds from above and below on the number density of clusters. © Taylor & Francis Group, LLC.
Resource Allocation Models and Accountability: A Jamaican Case Study
Nkrumah-Young, Kofi K.; Powell, Philip
2008-01-01
Higher education institutions (HEIs) may be funded privately, by the state or by a mixture of the two. Nevertheless, any state financing of HE necessitates a mechanism to determine the level of support and the channels through which it is to be directed; that is, a resource allocation model. Public funding, through resource allocation models,…
2011-06-14
... stakeholders to develop initiatives to test innovative payment and service delivery models to reduce program...] Medicare Program; Pioneer Accountable Care Organization Model; Extension of the Submission Deadlines for... of the Pioneer Accountable Care Organization Model letters of intent to June 30, 2011 and the...
Rigorous Science: a How-To Guide
Directory of Open Access Journals (Sweden)
Arturo Casadevall
2016-11-01
Full Text Available Proposals to improve the reproducibility of biomedical research have emphasized scientific rigor. Although the word “rigor” is widely used, there has been little specific discussion as to what it means and how it can be achieved. We suggest that scientific rigor combines elements of mathematics, logic, philosophy, and ethics. We propose a framework for rigor that includes redundant experimental design, sound statistical analysis, recognition of error, avoidance of logical fallacies, and intellectual honesty. These elements lead to five actionable recommendations for research education.
Accountability: a missing construct in models of adherence behavior and in clinical practice.
Oussedik, Elias; Foy, Capri G; Masicampo, E J; Kammrath, Lara K; Anderson, Robert E; Feldman, Steven R
2017-01-01
Piano lessons, weekly laboratory meetings, and visits to health care providers have in common an accountability that encourages people to follow a specified course of action. The accountability inherent in the social interaction between a patient and a health care provider affects patients' motivation to adhere to treatment. Nevertheless, accountability is a concept not found in adherence models, and is rarely employed in typical medical practice, where patients may be prescribed a treatment and not seen again until a return appointment 8-12 weeks later. The purpose of this paper is to describe the concept of accountability and to incorporate accountability into an existing adherence model framework. Based on the Self-Determination Theory, accountability can be considered in a spectrum from a paternalistic use of duress to comply with instructions (controlled accountability) to patients' autonomous internal desire to please a respected health care provider (autonomous accountability), the latter expected to best enhance long-term adherence behavior. Existing adherence models were reviewed with a panel of experts, and an accountability construct was incorporated into a modified version of Bandura's Social Cognitive Theory. Defining accountability and incorporating it into an adherence model will facilitate the development of measures of accountability as well as the testing and refinement of adherence interventions that make use of this critical determinant of human behavior.
Behavioural Procedural Models – a multipurpose mechanistic account
Directory of Open Access Journals (Sweden)
Leonardo Ivarola
2012-05-01
Full Text Available In this paper we outline an epistemological defence of what wecall Behavioural Procedural Models (BPMs, which represent the processes of individual decisions that lead to relevant economic patterns as psychologically (rather than rationally driven. Their general structure, and the way in which they may be incorporated to a multipurpose view of models, where the representational and interventionist goals are combined, is shown. It is argued that BPMs may provide “mechanistic-based explanations” in the sense defended by Hedström and Ylikoski (2010, which involve invariant regularities in Woodward’s sense. Such mechanisms provide a causal sort of explanation of anomalous economic patterns, which allow for extra marketintervention and manipulability in order to correct and improve some key individual decisions. This capability sets the basis for the so called libertarian paternalism (Sunstein and Thaler 2003.
Sumiyana, Sumiyana; Baridwan, Zaki
2015-01-01
This study investigates association between accounting fundamentals and variations of stock prices using recursive simultaneous equation model. The accounting fundamentalsconsist of earnings yield, book value, profitability, growth opportunities and discount rate. The prior single relationships model has been investigated by Chen and Zhang (2007),Sumiyana (2011) and Sumiyana et al. (2010). They assume that all accounting fundamentals associate direct-linearly to the stock returns. This study ...
Sumiyana, Sumiyana; Baridwan, Zaki
2013-01-01
This study investigates association between accounting fundamentals and variations of stock prices using recursive simultaneous equation model. The accounting fundamentalsconsist of earnings yield, book value, profitability, growth opportunities and discount rate. The prior single relationships model has been investigated by Chen and Zhang (2007),Sumiyana (2011) and Sumiyana et al. (2010). They assume that all accounting fundamentals associate direct-linearly to the stock returns. This study ...
HassabElnaby, Hassan R.; Dobrzykowski, David D.; Tran, Oanh Thikie
2012-01-01
Accounting has been faced with a severe shortage in the supply of qualified doctoral faculty. Drawing upon the international mobility of foreign scholars and the spirit of the international medical graduate program, this article suggests a model to fill the demand in accounting doctoral faculty. The underlying assumption of the suggested model is…
Towards accounting for dissolved iron speciation in global ocean models
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A. Tagliabue
2011-10-01
Full Text Available The trace metal iron (Fe is now routinely included in state-of-the-art ocean general circulation and biogeochemistry models (OGCBMs because of its key role as a limiting nutrient in regions of the world ocean important for carbon cycling and air-sea CO_{2} exchange. However, the complexities of the seawater Fe cycle, which impact its speciation and bioavailability, are simplified in such OGCBMs due to gaps in understanding and to avoid high computational costs. In a similar fashion to inorganic carbon speciation, we outline a means by which the complex speciation of Fe can be included in global OGCBMs in a reasonably cost-effective manner. We construct an Fe speciation model based on hypothesised relationships between rate constants and environmental variables (temperature, light, oxygen, pH, salinity and assumptions regarding the binding strengths of Fe complexing organic ligands and test hypotheses regarding their distributions. As a result, we find that the global distribution of different Fe species is tightly controlled by spatio-temporal environmental variability and the distribution of Fe binding ligands. Impacts on bioavailable Fe are highly sensitive to assumptions regarding which Fe species are bioavailable and how those species vary in space and time. When forced by representations of future ocean circulation and climate we find large changes to the speciation of Fe governed by pH mediated changes to redox kinetics. We speculate that these changes may exert selective pressure on phytoplankton Fe uptake strategies in the future ocean. In future work, more information on the sources and sinks of ocean Fe ligands, their bioavailability, the cycling of colloidal Fe species and kinetics of Fe-surface coordination reactions would be invaluable. We hope our modeling approach can provide a means by which new observations of Fe speciation can be tested against hypotheses of the processes present in governing the ocean Fe cycle in an
Spherical Detector Device Mathematical Modelling with Taking into Account Detector Module Symmetry
International Nuclear Information System (INIS)
Batyj, V.G.; Fedorchenko, D.V.; Prokopets, S.I.; Prokopets, I.M.; Kazhmuradov, M.A.
2005-01-01
Mathematical Model for spherical detector device accounting to symmetry properties is considered. Exact algorithm for simulation of measurement procedure with multiple radiation sources is developed. Modelling results are shown to have perfect agreement with calibration measurements
A mathematical model of sentimental dynamics accounting for marital dissolution.
Rey, José-Manuel
2010-03-31
Marital dissolution is ubiquitous in western societies. It poses major scientific and sociological problems both in theoretical and therapeutic terms. Scholars and therapists agree on the existence of a sort of second law of thermodynamics for sentimental relationships. Effort is required to sustain them. Love is not enough. Building on a simple version of the second law we use optimal control theory as a novel approach to model sentimental dynamics. Our analysis is consistent with sociological data. We show that, when both partners have similar emotional attributes, there is an optimal effort policy yielding a durable happy union. This policy is prey to structural destabilization resulting from a combination of two factors: there is an effort gap because the optimal policy always entails discomfort and there is a tendency to lower effort to non-sustaining levels due to the instability of the dynamics. These mathematical facts implied by the model unveil an underlying mechanism that may explain couple disruption in real scenarios. Within this framework the apparent paradox that a union consistently planned to last forever will probably break up is explained as a mechanistic consequence of the second law.
A mathematical model of sentimental dynamics accounting for marital dissolution.
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José-Manuel Rey
Full Text Available BACKGROUND: Marital dissolution is ubiquitous in western societies. It poses major scientific and sociological problems both in theoretical and therapeutic terms. Scholars and therapists agree on the existence of a sort of second law of thermodynamics for sentimental relationships. Effort is required to sustain them. Love is not enough. METHODOLOGY/PRINCIPAL FINDINGS: Building on a simple version of the second law we use optimal control theory as a novel approach to model sentimental dynamics. Our analysis is consistent with sociological data. We show that, when both partners have similar emotional attributes, there is an optimal effort policy yielding a durable happy union. This policy is prey to structural destabilization resulting from a combination of two factors: there is an effort gap because the optimal policy always entails discomfort and there is a tendency to lower effort to non-sustaining levels due to the instability of the dynamics. CONCLUSIONS/SIGNIFICANCE: These mathematical facts implied by the model unveil an underlying mechanism that may explain couple disruption in real scenarios. Within this framework the apparent paradox that a union consistently planned to last forever will probably break up is explained as a mechanistic consequence of the second law.
Nurse-directed care model in a psychiatric hospital: a model for clinical accountability.
E-Morris, Marlene; Caldwell, Barbara; Mencher, Kathleen J; Grogan, Kimberly; Judge-Gorny, Margaret; Patterson, Zelda; Christopher, Terrian; Smith, Russell C; McQuaide, Teresa
2010-01-01
The focus on recovery for persons with severe and persistent mental illness is leading state psychiatric hospitals to transform their method of care delivery. This article describes a quality improvement project involving a hospital's administration and multidisciplinary state-university affiliation that collaborated in the development and implementation of a nursing care delivery model in a state psychiatric hospital. The quality improvement project team instituted a new model to promote the hospital's vision of wellness and recovery through utilization of the therapeutic relationship and greater clinical accountability. Implementation of the model was accomplished in 2 phases: first, the establishment of a structure to lay the groundwork for accountability and, second, the development of a mechanism to provide a clinical supervision process for staff in their work with clients. Effectiveness of the model was assessed by surveys conducted at baseline and after implementation. Results indicated improvement in clinical practices and client living environment. As a secondary outcome, these improvements appeared to be associated with increased safety on the units evidenced by reduction in incidents of seclusion and restraint. Restructuring of the service delivery system of care so that clients are the center of clinical focus improves safety and can enhance the staff's attention to work with clients on their recovery. The role of the advanced practice nurse can influence the recovery of clients in state psychiatric hospitals. Future research should consider the impact on clients and their perceptions of the new service models.
Econometric modelling of Serbian current account determinants: Jackknife Model Averaging approach
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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.
A Simple Approach to Account for Climate Model Interdependence in Multi-Model Ensembles
Herger, N.; Abramowitz, G.; Angelil, O. M.; Knutti, R.; Sanderson, B.
2016-12-01
Multi-model ensembles are an indispensable tool for future climate projection and its uncertainty quantification. Ensembles containing multiple climate models generally have increased skill, consistency and reliability. Due to the lack of agreed-on alternatives, most scientists use the equally-weighted multi-model mean as they subscribe to model democracy ("one model, one vote").Different research groups are known to share sections of code, parameterizations in their model, literature, or even whole model components. Therefore, individual model runs do not represent truly independent estimates. Ignoring this dependence structure might lead to a false model consensus, wrong estimation of uncertainty and effective number of independent models.Here, we present a way to partially address this problem by selecting a subset of CMIP5 model runs so that its climatological mean minimizes the RMSE compared to a given observation product. Due to the cancelling out of errors, regional biases in the ensemble mean are reduced significantly.Using a model-as-truth experiment we demonstrate that those regional biases persist into the future and we are not fitting noise, thus providing improved observationally-constrained projections of the 21st century. The optimally selected ensemble shows significantly higher global mean surface temperature projections than the original ensemble, where all the model runs are considered. Moreover, the spread is decreased well beyond that expected from the decreased ensemble size.Several previous studies have recommended an ensemble selection approach based on performance ranking of the model runs. Here, we show that this approach can perform even worse than randomly selecting ensemble members and can thus be harmful. We suggest that accounting for interdependence in the ensemble selection process is a necessary step for robust projections for use in impact assessments, adaptation and mitigation of climate change.
MODEL OF ACCOUNTING ENGINEERING IN VIEW OF EARNINGS MANAGEMENT IN POLAND
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Leszek Michalczyk
2012-10-01
Full Text Available The article introduces the theoretical foundations of the author’s original concept of accounting engineering. We assume a theoretical premise whereby accounting engineering is understood as a system of accounting practice utilising differences in economic events resultant from the use of divergent accounting methods. Unlike, for instance, creative or praxeological accounting, accounting engineering is composed only, and under all circumstances, of lawful activities and adheres to the current regulations of the balance sheet law. The aim of the article is to construct a model of accounting engineering exploiting taking into account differences inherently present in variant accounting. These differences result in disparate financial results of identical economic events. Given the fact that regardless of which variant is used in accounting, all settlements are eventually equal to one another, a new class of differences emerges - the accounting engineering potential. It is transferred to subsequent reporting (balance sheet periods. In the end, the profit “made” in a given period reduces the financial result of future periods. This effect is due to the “transfer” of costs from one period to another. Such actions may have sundry consequences and are especially dangerous whenever many individuals are concerned with the profit of a given company, e.g. on a stock exchange. The reverse may be observed when a company is privatised and its value is being intentionally reduced by a controlled recording of accounting provisions, depending on the degree to which they are justified. The reduction of a company’s goodwill in Balcerowicz’s model of no-tender privatisation allows to justify the low value of the purchased company. These are only some of many manifestations of variant accounting which accounting engineering employs. A theoretical model of the latter is presented in this article.
Physiological studies of muscle rigor mortis in the fowl
International Nuclear Information System (INIS)
Nakahira, S.; Kaneko, K.; Tanaka, K.
1990-01-01
A simple system was developed for continuous measurement of muscle contraction during nor mortis. Longitudinal muscle strips dissected from the Peroneus Longus were suspended in a plastic tube containing liquid paraffin. Mechanical activity was transmitted to a strain-gauge transducer which is connected to a potentiometric pen-recorder. At the onset of measurement 1.2g was loaded on the muscle strip. This model was used to study the muscle response to various treatments during nor mortis. All measurements were carried out under the anaerobic condition at 17°C, except otherwise stated. 1. The present system was found to be quite useful for continuous measurement of muscle rigor course. 2. Muscle contraction under the anaerobic condition at 17°C reached a peak about 2 hours after the onset of measurement and thereafter it relaxed at a slow rate. In contrast, the aerobic condition under a high humidity resulted in a strong rigor, about three times stronger than that in the anaerobic condition. 3. Ultrasonic treatment (37, 000-47, 000Hz) at 25°C for 10 minutes resulted in a moderate muscle rigor. 4. Treatment of muscle strip with 2mM EGTA at 30°C for 30 minutes led to a relaxation of the muscle. 5. The muscle from the birds killed during anesthesia with pentobarbital sodium resulted in a slow rate of rigor, whereas the birds killed one day after hypophysectomy led to a quick muscle rigor as seen in intact controls. 6. A slight muscle rigor was observed when muscle strip was placed in a refrigerator at 0°C for 18.5 hours and thereafter temperature was kept at 17°C. (author)
Rigorous simulation: a tool to enhance decision making
Energy Technology Data Exchange (ETDEWEB)
Neiva, Raquel; Larson, Mel; Baks, Arjan [KBC Advanced Technologies plc, Surrey (United Kingdom)
2012-07-01
The world refining industries continue to be challenged by population growth (increased demand), regional market changes and the pressure of regulatory requirements to operate a 'green' refinery. Environmental regulations are reducing the value and use of heavy fuel oils, and leading to convert more of the heavier products or even heavier crude into lighter products while meeting increasingly stringent transportation fuel specifications. As a result actions are required for establishing a sustainable advantage for future success. Rigorous simulation provides a key advantage improving the time and efficient use of capital investment and maximizing profitability. Sustainably maximizing profit through rigorous modeling is achieved through enhanced performance monitoring and improved Linear Programme (LP) model accuracy. This paper contains examples on these two items. The combination of both increases overall rates of return. As refiners consider optimizing existing assets and expanding projects, the process agreed to achieve these goals is key for a successful profit improvement. The benefit of rigorous kinetic simulation with detailed fractionation allows for optimizing existing asset utilization while focusing the capital investment in the new unit(s), and therefore optimizing the overall strategic plan and return on investment. Individual process unit's monitoring works as a mechanism for validating and optimizing the plant performance. Unit monitoring is important to rectify poor performance and increase profitability. The key to a good LP relies upon the accuracy of the data used to generate the LP sub-model data. The value of rigorous unit monitoring are that the results are heat and mass balanced consistently, and are unique for a refiners unit / refinery. With the improved match of the refinery operation, the rigorous simulation models will allow capturing more accurately the non linearity of those process units and therefore provide correct
Krompecher, T
1981-01-01
Objective measurements were carried out to study the evolution of rigor mortis on rats at various temperatures. Our experiments showed that: (1) at 6 degrees C rigor mortis reaches full development between 48 and 60 hours post mortem, and is resolved at 168 hours post mortem; (2) at 24 degrees C rigor mortis reaches full development at 5 hours post mortem, and is resolved at 16 hours post mortem; (3) at 37 degrees C rigor mortis reaches full development at 3 hours post mortem, and is resolved at 6 hours post mortem; (4) the intensity of rigor mortis grows with increase in temperature (difference between values obtained at 24 degrees C and 37 degrees C); and (5) and 6 degrees C a "cold rigidity" was found, in addition to and independent of rigor mortis.
A Case Study of the Accounting Models for the Participants in an Emissions Trading Scheme
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Marius Deac
2013-10-01
Full Text Available As emissions trading schemes are becoming more popular across the world, accounting has to keep up with these new economic developments. The absence of guidance regarding the accounting for greenhouse gases (GHGs emissions generated by the withdrawal of IFRIC 3- Emission Rights - is the main reason why there is a diversity of accounting practices. This diversity of accounting methods makes the financial statements of companies that are taking part in emissions trading schemes like EU ETS, difficult to compare. The present paper uses a case study that assumes the existence of three entities that have chosen three different accounting methods: the IFRIC 3 cost model, the IFRIC 3 revaluation model and the “off balance sheet” approach. This illustrates how the choice of an accounting method regarding GHGs emissions influences their interim and annual reports through the chances in the companies’ balance sheet and financial results.
A new model in achieving Green Accounting at hotels in Bali
Astawa, I. P.; Ardina, C.; Yasa, I. M. S.; Parnata, I. K.
2018-01-01
The concept of green accounting becomes a debate in terms of its implementation in a company. The result of previous studies indicates that there are no standard model regarding its implementation to support performance. The research aims to create a different green accounting model to other models by using local cultural elements as the variables in building it. The research is conducted in two steps. The first step is designing the model based on theoretical studies by considering the main and supporting elements in building the concept of green accounting. The second step is conducting a model test at 60 five stars hotels started with data collection through questionnaire and followed by data processing using descriptive statistic. The result indicates that the hotels’ owner has implemented green accounting attributes and it supports previous studies. Another result, which is a new finding, shows that the presence of local culture, government regulation, and the awareness of hotels’ owner has important role in the development of green accounting concept. The results of the research give contribution to accounting science in terms of green reporting. The hotel management should adopt local culture in building the character of accountant hired in the accounting department.
"Rigor mortis" in a live patient.
Chakravarthy, Murali
2010-03-01
Rigor mortis is conventionally a postmortem change. Its occurrence suggests that death has occurred at least a few hours ago. The authors report a case of "Rigor Mortis" in a live patient after cardiac surgery. The likely factors that may have predisposed such premortem muscle stiffening in the reported patient are, intense low cardiac output status, use of unusually high dose of inotropic and vasopressor agents and likely sepsis. Such an event may be of importance while determining the time of death in individuals such as described in the report. It may also suggest requirement of careful examination of patients with muscle stiffening prior to declaration of death. This report is being published to point out the likely controversies that might arise out of muscle stiffening, which should not always be termed rigor mortis and/ or postmortem.
[Rigor mortis -- a definite sign of death?].
Heller, A R; Müller, M P; Frank, M D; Dressler, J
2005-04-01
In the past years an ongoing controversial debate exists in Germany, regarding quality of the coroner's inquest and declaration of death by physicians. We report the case of a 90-year old female, who was found after an unknown time following a suicide attempt with benzodiazepine. The examination of the patient showed livores (mortis?) on the left forearm and left lower leg. Moreover, rigor (mortis?) of the left arm was apparent which prevented arm flexion and extension. The hypothermic patient with insufficient respiration was intubated and mechanically ventilated. Chest compressions were not performed, because central pulses were (hardly) palpable and a sinus bradycardia 45/min (AV-block 2 degrees and sole premature ventricular complexes) was present. After placement of an intravenous line (17 G, external jugular vein) the hemodynamic situation was stabilized with intermittent boli of epinephrine and with sodium bicarbonate. With improved circulation livores and rigor disappeared. In the present case a minimal central circulation was noted, which could be stabilized, despite the presence of certain signs of death ( livores and rigor mortis). Considering the finding of an abrogated peripheral perfusion (livores), we postulate a centripetal collapse of glycogen and ATP supply in the patients left arm (rigor), which was restored after resuscitation and reperfusion. Thus, it appears that livores and rigor are not sensitive enough to exclude a vita minima, in particular in hypothermic patients with intoxications. Consequently a careful ABC-check should be performed even in the presence of apparently certain signs of death, to avoid underdiagnosing a vita minima. Additional ECG- monitoring is required to reduce the rate of false positive declarations of death. To what extent basic life support by paramedics should commence when rigor and livores are present until physician DNR order, deserves further discussion.
An Integrative Model of the Strategic Management Accounting at the Enterprises of Chemical Industry
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Aleksandra Vasilyevna Glushchenko
2016-06-01
Full Text Available Currently, the issues of information and analytical support of strategic management enabling to take timely and high-quality management decisions, are extremely relevant. Conflicting and poor information, haphazard collected in the practice of large companies from unreliable sources, affects the effective implementation of their development strategies and carries the threat of risk, by the increasing instability of the external environment. Thus chemical industry is one of the central places in the industry of Russia and, of course, has its specificity in the formation of the informationsupport system. Such an information system suitable for the development and implementation of strategic directions, changes in recognized competitive advantages of strategic management accounting. The issues of the lack of requirements for strategic accounting information, its inconsistency in the result of simultaneous accumulation in different parts and using different methods of calculation and assessment of indicators is impossible without a well-constructed model of organization of strategic management accounting. The purpose of this study is to develop such a model, the implementation of which will allow realizing the possibility of achieving strategic goals by harmonizing information from the individual objects of the strategic account to increase the functional effectiveness of management decisions with a focus on strategy. Case study was based on dialectical logic and methods of system analysis, and identifying causal relationships in building a model of strategic management accounting that contributes to the forecasts of its development. The study proposed to implement an integrative model of organization of strategic management accounting. The purpose of a phased implementation of this model defines the objects and tools of strategic management accounting. Moreover, it is determined that from the point of view of increasing the usefulness of management
A Dynamic Simulation Model of the Management Accounting Information Systems (MAIS)
Konstantopoulos, Nikolaos; Bekiaris, Michail G.; Zounta, Stella
2007-12-01
The aim of this paper is to examine the factors which determine the problems and the advantages on the design of management accounting information systems (MAIS). A simulation is carried out with a dynamic model of the MAIS design.
The Rigor Mortis of Education: Rigor Is Required in a Dying Educational System
Mixon, Jason; Stuart, Jerry
2009-01-01
In an effort to answer the "Educational Call to Arms", our national public schools have turned to Advanced Placement (AP) courses as the predominate vehicle used to address the lack of academic rigor in our public high schools. Advanced Placement is believed by many to provide students with the rigor and work ethic necessary to…
Illusory inferences from a disjunction of conditionals: a new mental models account.
Barrouillet, P; Lecas, J F
2000-08-14
(Johnson-Laird, P.N., & Savary, F. (1999, Illusory inferences: a novel class of erroneous deductions. Cognition, 71, 191-229.) have recently presented a mental models account, based on the so-called principle of truth, for the occurrence of inferences that are compelling but invalid. This article presents an alternative account of the illusory inferences resulting from a disjunction of conditionals. In accordance with our modified theory of mental models of the conditional, we show that the way individuals represent conditionals leads them to misinterpret the locus of the disjunction and prevents them from drawing conclusions from a false conditional, thus accounting for the compelling character of the illusory inference.
Taking into account of the Pauli principle in the quasiparticle-phonon nuclear model
International Nuclear Information System (INIS)
Solov'ev, V.G.
1979-01-01
The effect of an exact account taken of the Pauli principle and correlations in ground states in calculations in the framework of the quasiparticle-phonon model of a nucleus has been studied. It is elucidated when it is possible to use the random phase approximation (RPA) and when the Pauli principle should be exactly taken into account. It has been shown that in the quasiparticle-phonon model of a nucleus one may perform calculations with a precise account of the Pauli principle. In most of the problems calculations can be carried out with RPA-phonons
Vysotskaya, Anna; Kolvakh, Oleg; Stoner, Greg
2016-01-01
The aim of this paper is to describe the innovative teaching approach used in the Southern Federal University, Russia, to teach accounting via a form of matrix mathematics. It thereby contributes to disseminating the technique of teaching to solve accounting cases using mutual calculations to a worldwide audience. The approach taken in this course…
2011-05-20
... Affordable Care Act, to test innovative payment and service delivery models that reduce spending under.... This Model will test the effectiveness of a combination of the following: Payment arrangements that...] Medicare Program; Pioneer Accountable Care Organization Model: Request for Applications AGENCY: Centers for...
Trends: Rigor Mortis in the Arts.
Blodget, Alden S.
1991-01-01
Outlines how past art education provided a refuge for students from the rigors of other academic subjects. Observes that in recent years art education has become "discipline based." Argues that art educators need to reaffirm their commitment to a humanistic way of knowing. (KM)
Stochastic Geometry and Quantum Gravity: Some Rigorous Results
Zessin, H.
The aim of these lectures is a short introduction into some recent developments in stochastic geometry which have one of its origins in simplicial gravity theory (see Regge Nuovo Cimento 19: 558-571, 1961). The aim is to define and construct rigorously point processes on spaces of Euclidean simplices in such a way that the configurations of these simplices are simplicial complexes. The main interest then is concentrated on their curvature properties. We illustrate certain basic ideas from a mathematical point of view. An excellent representation of this area can be found in Schneider and Weil (Stochastic and Integral Geometry, Springer, Berlin, 2008. German edition: Stochastische Geometrie, Teubner, 2000). In Ambjørn et al. (Quantum Geometry Cambridge University Press, Cambridge, 1997) you find a beautiful account from the physical point of view. More recent developments in this direction can be found in Ambjørn et al. ("Quantum gravity as sum over spacetimes", Lect. Notes Phys. 807. Springer, Heidelberg, 2010). After an informal axiomatic introduction into the conceptual foundations of Regge's approach the first lecture recalls the concepts and notations used. It presents the fundamental zero-infinity law of stochastic geometry and the construction of cluster processes based on it. The second lecture presents the main mathematical object, i.e. Poisson-Delaunay surfaces possessing an intrinsic random metric structure. The third and fourth lectures discuss their ergodic behaviour and present the two-dimensional Regge model of pure simplicial quantum gravity. We terminate with the formulation of basic open problems. Proofs are given in detail only in a few cases. In general the main ideas are developed. Sufficiently complete references are given.
Rigorous results on measuring the quark charge below color threshold
International Nuclear Information System (INIS)
Lipkin, H.J.
1979-01-01
Rigorous theorems are presented showing that contributions from a color nonsinglet component of the current to matrix elements of a second order electromagnetic transition are suppressed by factors inversely proportional to the energy of the color threshold. Parton models which obtain matrix elements proportional to the color average of the square of the quark charge are shown to neglect terms of the same order of magnitude as terms kept. (author)
Accountability: a missing construct in models of adherence behavior and in clinical practice
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Oussedik E
2017-07-01
Full Text Available Elias Oussedik,1 Capri G Foy,2 E J Masicampo,3 Lara K Kammrath,3 Robert E Anderson,1 Steven R Feldman1,4,5 1Center for Dermatology Research, Department of Dermatology, Wake Forest School of Medicine, Winston-Salem, NC, USA; 2Department of Social Sciences and Health Policy, Wake Forest School of Medicine, Winston-Salem, NC, USA; 3Department of Psychology, Wake Forest University, Winston-Salem, NC, USA; 4Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, USA; 5Department of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA Abstract: Piano lessons, weekly laboratory meetings, and visits to health care providers have in common an accountability that encourages people to follow a specified course of action. The accountability inherent in the social interaction between a patient and a health care provider affects patients’ motivation to adhere to treatment. Nevertheless, accountability is a concept not found in adherence models, and is rarely employed in typical medical practice, where patients may be prescribed a treatment and not seen again until a return appointment 8–12 weeks later. The purpose of this paper is to describe the concept of accountability and to incorporate accountability into an existing adherence model framework. Based on the Self-Determination Theory, accountability can be considered in a spectrum from a paternalistic use of duress to comply with instructions (controlled accountability to patients’ autonomous internal desire to please a respected health care provider (autonomous accountability, the latter expected to best enhance long-term adherence behavior. Existing adherence models were reviewed with a panel of experts, and an accountability construct was incorporated into a modified version of Bandura’s Social Cognitive Theory. Defining accountability and incorporating it into an adherence model will facilitate the development of measures of accountability as well
Dutta, Dushmanta; Vaze, Jai; Kim, Shaun; Hughes, Justin; Yang, Ang; Teng, Jin; Lerat, Julien
2017-04-01
Existing global and continental scale river models, mainly designed for integrating with global climate models, are of very coarse spatial resolutions and lack many important hydrological processes, such as overbank flow, irrigation diversion, groundwater seepage/recharge, which operate at a much finer resolution. Thus, these models are not suitable for producing water accounts, which have become increasingly important for water resources planning and management at regional and national scales. A continental scale river system model called Australian Water Resource Assessment River System model (AWRA-R) has been developed and implemented for national water accounting in Australia using a node-link architecture. The model includes major hydrological processes, anthropogenic water utilisation and storage routing that influence the streamflow in both regulated and unregulated river systems. Two key components of the model are an irrigation model to compute water diversion for irrigation use and associated fluxes and stores and a storage-based floodplain inundation model to compute overbank flow from river to floodplain and associated floodplain fluxes and stores. The results in the Murray-Darling Basin shows highly satisfactory performance of the model with median daily Nash-Sutcliffe Efficiency (NSE) of 0.64 and median annual bias of less than 1% for the period of calibration (1970-1991) and median daily NSE of 0.69 and median annual bias of 12% for validation period (1992-2014). The results have demonstrated that the performance of the model is less satisfactory when the key processes such as overbank flow, groundwater seepage and irrigation diversion are switched off. The AWRA-R model, which has been operationalised by the Australian Bureau of Meteorology for continental scale water accounting, has contributed to improvements in the national water account by substantially reducing accounted different volume (gain/loss).
Accounting for model error due to unresolved scales within ensemble Kalman filtering
Mitchell, Lewis; Carrassi, Alberto
2014-01-01
We propose a method to account for model error due to unresolved scales in the context of the ensemble transform Kalman filter (ETKF). The approach extends to this class of algorithms the deterministic model error formulation recently explored for variational schemes and extended Kalman filter. The model error statistic required in the analysis update is estimated using historical reanalysis increments and a suitable model error evolution law. Two different versions of the method are describe...
A Social Accountable Model for Medical Education System in Iran: A Grounded-Theory
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Mohammadreza Abdolmaleki
2017-10-01
Full Text Available Social accountability has been increasingly discussed over the past three decades in various fields providing service to the community and has been expressed as a goal for various areas. In medical education system, like other social accountability areas, it is considered as one of the main objectives globally. The aim of this study was to seek a social accountability theory in the medical education system that is capable of identifying all the standards, norms, and conditions within the country related to the study subject and recognize their relationship. In this study, a total of eight experts in the field of social accountability in medical education system with executive or study experience were interviewedpersonally. After analysis of interviews, 379 codes, 59 secondary categories, 16 subcategories, and 9 main categories were obtained. The resulting data was collected and analyzed at three levels of open coding, axial coding, and selective coding in the form of grounded theory study of “Accountability model of medical education in Iran”, which can be used in education system’s policies and planning for social accountability, given that almost all effective components of social accountability in highereducation health system with causal and facilitator associations were determined.Keywords: SOCIAL ACCOUNTABILITY, COMMUNITY–ORIENTED MEDICINE, COMMUNITY MEDICINE, EDUCATION SYSTEM, GROUNDED THEORY
Toward a Useful Model for Group Mentoring in Public Accounting Firms
Directory of Open Access Journals (Sweden)
Steven J. Johnson
2013-07-01
Full Text Available Today’s public accounting firms face a number of challenges in relation to their most valuable resource and primary revenue generator, human capital. Expanding regulations, technology advances, increased competition and high turnover rates are just a few of the issues confronting public accounting leaders in today’s complex business environment. In recent years, some public accounting firms have attempted to combat low retention and high burnout rates with traditional one-to-one mentoring programs, with varying degrees of success. Many firms have found that they lack the resources necessary to successfully implement and maintain such programs. In other industries, organizations have used a group mentoring approach in attempt to remove potential barriers to mentoring success. Although the research regarding group mentoring shows promise for positive organizational outcomes, no cases could be found in the literature regarding its usage in a public accounting firm. Because of the unique challenges associated with public accounting firms, this paper attempts to answer two questions: (1Does group mentoring provide a viable alternative to traditional mentoring in a public accounting firm? (2 If so, what general model might be used for implementing such a program? In answering these questions, a review of the group mentoring literature is provided, along with a suggested model for the implementation of group mentoring in a public accounting firm.
A simulation model of hospital management based on cost accounting analysis according to disease.
Tanaka, Koji; Sato, Junzo; Guo, Jinqiu; Takada, Akira; Yoshihara, Hiroyuki
2004-12-01
Since a little before 2000, hospital cost accounting has been increasingly performed at Japanese national university hospitals. At Kumamoto University Hospital, for instance, departmental costs have been analyzed since 2000. And, since 2003, the cost balance has been obtained according to certain diseases for the preparation of Diagnosis-Related Groups and Prospective Payment System. On the basis of these experiences, we have constructed a simulation model of hospital management. This program has worked correctly at repeated trials and with satisfactory speed. Although there has been room for improvement of detailed accounts and cost accounting engine, the basic model has proved satisfactory. We have constructed a hospital management model based on the financial data of an existing hospital. We will later improve this program from the viewpoint of construction and using more various data of hospital management. A prospective outlook may be obtained for the practical application of this hospital management model.
Rigorous description of holograms of particles illuminated by an astigmatic elliptical Gaussian beam
Energy Technology Data Exchange (ETDEWEB)
Yuan, Y J; Ren, K F; Coetmellec, S; Lebrun, D, E-mail: fang.ren@coria.f [UMR 6614/CORIA, CNRS and Universite et INSA de Rouen Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France)
2009-02-01
The digital holography is a non-intrusive optical metrology and well adapted for the measurement of the size and velocity field of particles in the spray of a fluid. The simplified model of an opaque disk is often used in the treatment of the diagrams and therefore the refraction and the third dimension diffraction of the particle are not taken into account. We present in this paper a rigorous description of the holographic diagrams and evaluate the effects of the refraction and the third dimension diffraction by comparison to the opaque disk model. It is found that the effects are important when the real part of the refractive index is near unity or the imaginary part is non zero but small.
Facility level SSAC for model country - an introduction and material balance accounting principles
International Nuclear Information System (INIS)
Jones, R.J.
1989-01-01
A facility level State System of Accounting for and Control of Nuclear Materials (SSAC) for a model country and the principles of materials balance accounting relating to that country are described. The seven principal elements of a SSAC are examined and a facility level system based on them discussed. The seven elements are organization and management; nuclear material measurements; measurement quality; records and reports; physical inventory taking; material balance closing; containment and surveillance. 11 refs., 19 figs., 5 tabs
Rossouw, Riaan; Saayman, Melville
2011-01-01
Historically, tourism policy analysis in South Africa has posed challenges to accurate measurement. The primary reason for this is that tourism is not designated as an 'industry' in standard economic accounts. This paper therefore demonstrates the relevance and need for applied general equilibrium (AGE) models to be completed and extended through an integration with tourism satellite accounts (TSAs) as a tool for policy makers (especially tourism policy makers) in South Africa. The paper sets...
Shadow Segmentation and Augmentation Using á-overlay Models that Account for Penumbra
DEFF Research Database (Denmark)
Nielsen, Michael; Madsen, Claus B.
2006-01-01
that an augmented virtual object can cast an exact shadow. The penumbras (half-shadows) must be taken into account so that we can model the soft shadows.We hope to achieve this by modelling the shadow regions (umbra and penumbra alike) with a transparent overlay. This paper reviews the state-of-the-art shadow...
van Barneveld, Christina; Stienstra, Wendy; Stewart, Sandra
2006-01-01
For this study we analyzed the content of school board improvement plans in relation to the Achievement-Indicators-Policy (AIP) model of educational accountability (Nagy, Demeris, & van Barneveld, 2000). We identified areas of congruence and incongruence between the plans and the model. Results suggested that the content of the improvement…
Lessons learned for spatial modelling of ecosystem services in support of ecosystem accounting
Schroter, M.; Remme, R.P.; Sumarga, E.; Barton, D.N.; Hein, L.G.
2015-01-01
Assessment of ecosystem services through spatial modelling plays a key role in ecosystem accounting. Spatial models for ecosystem services try to capture spatial heterogeneity with high accuracy. This endeavour, however, faces several practical constraints. In this article we analyse the trade-offs
Model Selection and Accounting for Model Uncertainty in Graphical Models Using OCCAM’s Window
1991-07-22
mental work; C, strenuous physical work; D, systolic blood pressure: E. ratio of 13 and Qt proteins; F, family anamnesis of coronary heart disease...of F, family anamnesis . The models are shown in Figure 4. 12 Table 1: Risk factors for Coronary lfeart Disea:W B No Yes A No Yes No Yes F E D C...a link from smoking (A) to systolic blood pressure (D). There is decisive evidence in favour of the marginal independence of family anamnesis of
Accounting for differences in dieting status: steps in the refinement of a model.
Huon, G; Hayne, A; Gunewardene, A; Strong, K; Lunn, N; Piira, T; Lim, J
1999-12-01
The overriding objective of this paper is to outline the steps involved in refining a structural model to explain differences in dieting status. Cross-sectional data (representing the responses of 1,644 teenage girls) derive from the preliminary testing in a 3-year longitudinal study. A battery of measures assessed social influence, vulnerability (to conformity) disposition, protective (social coping) skills, and aspects of positive familial context as core components in a model proposed to account for the initiation of dieting. Path analyses were used to establish the predictive ability of those separate components and their interrelationships in accounting for differences in dieting status. Several components of the model were found to be important predictors of dieting status. The model incorporates significant direct, indirect (or mediated), and moderating relationships. Taking all variables into account, the strongest prediction of dieting status was from peer competitiveness, using a new scale developed specifically for this study. Systematic analyses are crucial for the refinement of models to be used in large-scale multivariate studies. In the short term, the model investigated in this study has been shown to be useful in accounting for cross-sectional differences in dieting status. The refined model will be most powerfully employed in large-scale time-extended studies of the initiation of dieting to lose weight. Copyright 1999 by John Wiley & Sons, Inc.
A Two-Account Life Insurance Model for Scenario-Based Valuation Including Event Risk
DEFF Research Database (Denmark)
Jensen, Ninna Reitzel; Schomacker, Kristian Juul
2015-01-01
Using a two-account model with event risk, we model life insurance contracts taking into account both guaranteed and non-guaranteed payments in participating life insurance as well as in unit-linked insurance. Here, event risk is used as a generic term for life insurance events, such as death......, disability, etc. In our treatment of participating life insurance, we have special focus on the bonus schemes “consolidation” and “additional benefits”, and one goal is to formalize how these work and interact. Another goal is to describe similarities and differences between participating life insurance...... product types. This enables comparison of participating life insurance products and unit-linked insurance products, thus building a bridge between the two different ways of formalizing life insurance products. Finally, our model distinguishes itself from the existing literature by taking into account...
Microscopic model accounting of 2p2p configurations in magic nuclei
International Nuclear Information System (INIS)
Kamerdzhiev, S.P.
1983-01-01
A model for account of the 2p2h configurations in magic nuclei is described in the framework of the Green function formalism. The model is formulated in the lowest order in the phonon production amplitude, so that the series are expansions not over pure 2p2h configurations, but over con figurations of the type ''1p1h+phonon''. Equations are obtained for the vertex and the density matrix, as well as an expression for the transition probabilities, that are extensions of the corresponding results of the theory of finite Fermi systems, or of the random-phase approximation to the case where the ''1p1h+phonon'' configurations are taken into account. Corrections to the one-particle phenomenological basis which arise with account for complicated configurations are obtained. Comparison with other approaches, using phonons, has shown that they are particular cases of the described model
DEFF Research Database (Denmark)
Hansen, Thomas Mejer; Cordua, Knud Skou; Holm Jacobsen, Bo
2014-01-01
forward models, can be more than an order of magnitude larger than the measurement uncertainty. We also found that the modeling error is strongly linked to the spatial variability of the assumed velocity field, i.e., the a priori velocity model.We discovered some general tools by which the modeling error...... synthetic ground-penetrating radar crosshole tomographic inverse problems. Ignoring the modeling error can lead to severe artifacts, which erroneously appear to be well resolved in the solution of the inverse problem. Accounting for the modeling error leads to a solution of the inverse problem consistent...
Modelling characteristics of photovoltaic panels with thermal phenomena taken into account
International Nuclear Information System (INIS)
Krac, Ewa; Górecki, Krzysztof
2016-01-01
In the paper a new form of the electrothermal model of photovoltaic panels is proposed. This model takes into account the optical, electrical and thermal properties of the considered panels, as well as electrical and thermal properties of the protecting circuit and thermal inertia of the considered panels. The form of this model is described and some results of measurements and calculations of mono-crystalline and poly-crystalline panels are presented
Cressie, Noel; Calder, Catherine A; Clark, James S; Ver Hoef, Jay M; Wikle, Christopher K
2009-04-01
Analyses of ecological data should account for the uncertainty in the process(es) that generated the data. However, accounting for these uncertainties is a difficult task, since ecology is known for its complexity. Measurement and/or process errors are often the only sources of uncertainty modeled when addressing complex ecological problems, yet analyses should also account for uncertainty in sampling design, in model specification, in parameters governing the specified model, and in initial and boundary conditions. Only then can we be confident in the scientific inferences and forecasts made from an analysis. Probability and statistics provide a framework that accounts for multiple sources of uncertainty. Given the complexities of ecological studies, the hierarchical statistical model is an invaluable tool. This approach is not new in ecology, and there are many examples (both Bayesian and non-Bayesian) in the literature illustrating the benefits of this approach. In this article, we provide a baseline for concepts, notation, and methods, from which discussion on hierarchical statistical modeling in ecology can proceed. We have also planted some seeds for discussion and tried to show where the practical difficulties lie. Our thesis is that hierarchical statistical modeling is a powerful way of approaching ecological analysis in the presence of inevitable but quantifiable uncertainties, even if practical issues sometimes require pragmatic compromises.
The Anachronism of the Local Public Accountancy Determinate by the Accrual European Model
Directory of Open Access Journals (Sweden)
Riana Iren RADU
2009-01-01
Full Text Available Placing the European accrual model upon cash accountancy model,presently used in Romania, at the level of the local communities, makespossible that the anachronism of the model to manifest itself on the discussion’sconcentration at the nominalization about the model’s inclusion in everydaypublic practice. The basis of the accrual model were first defined in the lawregarding the commercial societies adopted in Great Britain in 1985, when theydetermined that all income and taxes referring to the financial year “will betaken into consideration without any boundary to the reception or paymentdate.”1 The accrual model in accountancy needs the recording of the non-casheffects in transactions or financial events for their appearance periods and not inany generated cash, received or paid. The business development was the basisfor “sophistication” of the recordings of the transactions and financial events,being prerequisite for recording the debtors’ or creditors’ sums.
Multiple imputation to account for measurement error in marginal structural models
Edwards, Jessie K.; Cole, Stephen R.; Westreich, Daniel; Crane, Heidi; Eron, Joseph J.; Mathews, W. Christopher; Moore, Richard; Boswell, Stephen L.; Lesko, Catherine R.; Mugavero, Michael J.
2015-01-01
Background Marginal structural models are an important tool for observational studies. These models typically assume that variables are measured without error. We describe a method to account for differential and non-differential measurement error in a marginal structural model. Methods We illustrate the method estimating the joint effects of antiretroviral therapy initiation and current smoking on all-cause mortality in a United States cohort of 12,290 patients with HIV followed for up to 5 years between 1998 and 2011. Smoking status was likely measured with error, but a subset of 3686 patients who reported smoking status on separate questionnaires composed an internal validation subgroup. We compared a standard joint marginal structural model fit using inverse probability weights to a model that also accounted for misclassification of smoking status using multiple imputation. Results In the standard analysis, current smoking was not associated with increased risk of mortality. After accounting for misclassification, current smoking without therapy was associated with increased mortality [hazard ratio (HR): 1.2 (95% CI: 0.6, 2.3)]. The HR for current smoking and therapy (0.4 (95% CI: 0.2, 0.7)) was similar to the HR for no smoking and therapy (0.4; 95% CI: 0.2, 0.6). Conclusions Multiple imputation can be used to account for measurement error in concert with methods for causal inference to strengthen results from observational studies. PMID:26214338
Multiple Imputation to Account for Measurement Error in Marginal Structural Models.
Edwards, Jessie K; Cole, Stephen R; Westreich, Daniel; Crane, Heidi; Eron, Joseph J; Mathews, W Christopher; Moore, Richard; Boswell, Stephen L; Lesko, Catherine R; Mugavero, Michael J
2015-09-01
Marginal structural models are an important tool for observational studies. These models typically assume that variables are measured without error. We describe a method to account for differential and nondifferential measurement error in a marginal structural model. We illustrate the method estimating the joint effects of antiretroviral therapy initiation and current smoking on all-cause mortality in a United States cohort of 12,290 patients with HIV followed for up to 5 years between 1998 and 2011. Smoking status was likely measured with error, but a subset of 3,686 patients who reported smoking status on separate questionnaires composed an internal validation subgroup. We compared a standard joint marginal structural model fit using inverse probability weights to a model that also accounted for misclassification of smoking status using multiple imputation. In the standard analysis, current smoking was not associated with increased risk of mortality. After accounting for misclassification, current smoking without therapy was associated with increased mortality (hazard ratio [HR]: 1.2 [95% confidence interval [CI] = 0.6, 2.3]). The HR for current smoking and therapy [0.4 (95% CI = 0.2, 0.7)] was similar to the HR for no smoking and therapy (0.4; 95% CI = 0.2, 0.6). Multiple imputation can be used to account for measurement error in concert with methods for causal inference to strengthen results from observational studies.
Kobayashi, Masahiko; Takemori, Shigeru; Yamaguchi, Maki
2004-02-10
Based on the molecular mechanism of rigor mortis, we have proposed that stiffness (elastic modulus evaluated with tension response against minute length perturbations) can be a suitable index of post-mortem rigidity in skeletal muscle. To trace the developmental process of rigor mortis, we measured stiffness and tension in both red and white rat skeletal muscle kept in liquid paraffin at 37 and 25 degrees C. White muscle (in which type IIB fibres predominate) developed stiffness and tension significantly more slowly than red muscle, except for soleus red muscle at 25 degrees C, which showed disproportionately slow rigor development. In each of the examined muscles, stiffness and tension developed more slowly at 25 degrees C than at 37 degrees C. In each specimen, tension always reached its maximum level earlier than stiffness, and then decreased more rapidly and markedly than stiffness. These phenomena may account for the sequential progress of rigor mortis in human cadavers.
Directory of Open Access Journals (Sweden)
Traykov Alexander
2015-01-01
Full Text Available Numerical studies are performed on computer models taking into account the stages of construction and time dependent material properties defined in two forms. A 2D model of three storey two spans frame is created. The first form deals with material defined in the usual design practice way - without taking into account the time dependent properties of the concrete. The second form creep and shrinkage of the concrete are taken into account. Displacements and internal forces in specific elements and sections are reported. The influence of the time dependent material properties on the displacement and the internal forces in the main structural elements is tracked down. The results corresponding to the two forms of material definition are compared together as well as with the results obtained by the usual design calculations. Conclusions on the influence of the concrete creep and shrinkage during the construction towards structural behaviour are made.
Software metrics a rigorous and practical approach
Fenton, Norman
2014-01-01
A Framework for Managing, Measuring, and Predicting Attributes of Software Development Products and ProcessesReflecting the immense progress in the development and use of software metrics in the past decades, Software Metrics: A Rigorous and Practical Approach, Third Edition provides an up-to-date, accessible, and comprehensive introduction to software metrics. Like its popular predecessors, this third edition discusses important issues, explains essential concepts, and offers new approaches for tackling long-standing problems.New to the Third EditionThis edition contains new material relevant
A Two-Account Life Insurance Model for Scenario-Based Valuation Including Event Risk
Directory of Open Access Journals (Sweden)
Ninna Reitzel Jensen
2015-06-01
Full Text Available Using a two-account model with event risk, we model life insurance contracts taking into account both guaranteed and non-guaranteed payments in participating life insurance as well as in unit-linked insurance. Here, event risk is used as a generic term for life insurance events, such as death, disability, etc. In our treatment of participating life insurance, we have special focus on the bonus schemes “consolidation” and “additional benefits”, and one goal is to formalize how these work and interact. Another goal is to describe similarities and differences between participating life insurance and unit-linked insurance. By use of a two-account model, we are able to illustrate general concepts without making the model too abstract. To allow for complicated financial markets without dramatically increasing the mathematical complexity, we focus on economic scenarios. We illustrate the use of our model by conducting scenario analysis based on Monte Carlo simulation, but the model applies to scenarios in general and to worst-case and best-estimate scenarios in particular. In addition to easy computations, our model offers a common framework for the valuation of life insurance payments across product types. This enables comparison of participating life insurance products and unit-linked insurance products, thus building a bridge between the two different ways of formalizing life insurance products. Finally, our model distinguishes itself from the existing literature by taking into account the Markov model for the state of the policyholder and, hereby, facilitating event risk.
Development of rigor mortis is not affected by muscle volume.
Kobayashi, M; Ikegaya, H; Takase, I; Hatanaka, K; Sakurada, K; Iwase, H
2001-04-01
There is a hypothesis suggesting that rigor mortis progresses more rapidly in small muscles than in large muscles. We measured rigor mortis as tension determined isometrically in rat musculus erector spinae that had been cut into muscle bundles of various volumes. The muscle volume did not influence either the progress or the resolution of rigor mortis, which contradicts the hypothesis. Differences in pre-rigor load on the muscles influenced the onset and resolution of rigor mortis in a few pairs of samples, but did not influence the time taken for rigor mortis to reach its full extent after death. Moreover, the progress of rigor mortis in this muscle was biphasic; this may reflect the early rigor of red muscle fibres and the late rigor of white muscle fibres.
2011-01-01
The effectiveness of and adherence to eHealth interventions is enhanced by human support. However, human support has largely not been manualized and has usually not been guided by clear models. The objective of this paper is to develop a clear theoretical model, based on relevant empirical literature, that can guide research into human support components of eHealth interventions. A review of the literature revealed little relevant information from clinical sciences. Applicable literature was drawn primarily from organizational psychology, motivation theory, and computer-mediated communication (CMC) research. We have developed a model, referred to as “Supportive Accountability.” We argue that human support increases adherence through accountability to a coach who is seen as trustworthy, benevolent, and having expertise. Accountability should involve clear, process-oriented expectations that the patient is involved in determining. Reciprocity in the relationship, through which the patient derives clear benefits, should be explicit. The effect of accountability may be moderated by patient motivation. The more intrinsically motivated patients are, the less support they likely require. The process of support is also mediated by the communications medium (eg, telephone, instant messaging, email). Different communications media each have their own potential benefits and disadvantages. We discuss the specific components of accountability, motivation, and CMC medium in detail. The proposed model is a first step toward understanding how human support enhances adherence to eHealth interventions. Each component of the proposed model is a testable hypothesis. As we develop viable human support models, these should be manualized to facilitate dissemination. PMID:21393123
Accounting for Co-Teaching: A Guide for Policymakers and Developers of Value-Added Models
Isenberg, Eric; Walsh, Elias
2015-01-01
We outline the options available to policymakers for addressing co-teaching in a value-added model. Building on earlier work, we propose an improvement to a method of accounting for co-teaching that treats co-teachers as teams, with each teacher receiving equal credit for co-taught students. Hock and Isenberg (2012) described a method known as the…
Gao, H.; Hrachowitz, M.; Sriwongsitanon, Nutchanart; Fenicia, F.; Gharari, S.; Savenije, H.H.G.
2016-01-01
Understanding which catchment characteristics dominate hydrologic response and how to take them into account remains a challenge in hydrological modeling, particularly in ungauged basins. This is even more so in nontemperate and nonhumid catchments, where—due to the combination of seasonality and
Lincove, Jane Arnold; Osborne, Cynthia; Dillon, Amanda; Mills, Nicholas
2014-01-01
Despite questions about validity and reliability, the use of value-added estimation methods has moved beyond academic research into state accountability systems for teachers, schools, and teacher preparation programs (TPPs). Prior studies of value-added measurement for TPPs test the validity of researcher-designed models and find that measuring…
Developing a Model for Identifying Students at Risk of Failure in a First Year Accounting Unit
Smith, Malcolm; Therry, Len; Whale, Jacqui
2012-01-01
This paper reports on the process involved in attempting to build a predictive model capable of identifying students at risk of failure in a first year accounting unit in an Australian university. Identifying attributes that contribute to students being at risk can lead to the development of appropriate intervention strategies and support…
A creep rupture model accounting for cavitation at sliding grain boundaries
Giessen, Erik van der; Tvergaard, Viggo
1991-01-01
An axisymmetric cell model analysis is used to study creep failure by grain boundary cavitation at facets normal to the maximum principal tensile stress, taking into account the influence of cavitation and sliding at adjacent inclined grain boundaries. It is found that the interaction between the
Towards New Empirical Versions of Financial and Accounting Models Corrected for Measurement Errors
Francois-Éric Racicot; Raymond Théoret; Alain Coen
2006-01-01
In this paper, we propose a new empirical version of the Fama and French Model based on the Hausman (1978) specification test and aimed at discarding measurement errors in the variables. The proposed empirical framework is general enough to be used for correcting other financial and accounting models of measurement errors. Removing measurement errors is important at many levels as information disclosure, corporate governance and protection of investors.
Reike, Dennis; Schwarz, Wolf
2016-01-01
The time required to determine the larger of 2 digits decreases with their numerical distance, and, for a given distance, increases with their magnitude (Moyer & Landauer, 1967). One detailed quantitative framework to account for these effects is provided by random walk models. These chronometric models describe how number-related noisy…
Taking into account for the Pauli principle in particle-vibrator model
International Nuclear Information System (INIS)
Knyaz'kov, O.M.
1985-01-01
To construct Hamiltonian of the particle interaction and phonons a semimicroscopic approach developed by the author earlier is used. At that the Pauli principle is taken account of in local formalism of density matrix. Analytical expressions permitting in a closed form to solve a task of taking account of the Pauli principle in the particle-vibrator model have been derived. Unlike a phenomenological approach form factors of inelastic transitions are determined with parameters of effective nucleon-nucleon forces, central and transition densities and contain no free parameters
Accounting of inter-electron correlations in the model of mobile electron shells
International Nuclear Information System (INIS)
Panov, Yu.D.; Moskvin, A.S.
2000-01-01
One studied the basic peculiar features of the model for mobile electron shells for multielectron atom or cluster. One offered a variation technique to take account of the electron correlations where the coordinates of the centre of single-particle atomic orbital served as variation parameters. It enables to interpret dramatically variation of electron density distribution under anisotropic external effect in terms of the limited initial basis. One studied specific correlated states that might make correlation contribution into the orbital current. Paper presents generalization of the typical MO-LCAO pattern with the limited set of single particle functions enabling to take account of additional multipole-multipole interactions in the cluster [ru
Bennett, Iain; Paracha, Noman; Abrams, Keith; Ray, Joshua
2018-01-01
Rank Preserving Structural Failure Time models are one of the most commonly used statistical methods to adjust for treatment switching in oncology clinical trials. The method is often applied in a decision analytic model without appropriately accounting for additional uncertainty when determining the allocation of health care resources. The aim of the study is to describe novel approaches to adequately account for uncertainty when using a Rank Preserving Structural Failure Time model in a decision analytic model. Using two examples, we tested and compared the performance of the novel Test-based method with the resampling bootstrap method and with the conventional approach of no adjustment. In the first example, we simulated life expectancy using a simple decision analytic model based on a hypothetical oncology trial with treatment switching. In the second example, we applied the adjustment method on published data when no individual patient data were available. Mean estimates of overall and incremental life expectancy were similar across methods. However, the bootstrapped and test-based estimates consistently produced greater estimates of uncertainty compared with the estimate without any adjustment applied. Similar results were observed when using the test based approach on a published data showing that failing to adjust for uncertainty led to smaller confidence intervals. Both the bootstrapping and test-based approaches provide a solution to appropriately incorporate uncertainty, with the benefit that the latter can implemented by researchers in the absence of individual patient data. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.
Accounting for covariate measurement error in a Cox model analysis of recurrence of depression.
Liu, K; Mazumdar, S; Stone, R A; Dew, M A; Houck, P R; Reynolds, C F
2001-01-01
When a covariate measured with error is used as a predictor in a survival analysis using the Cox model, the parameter estimate is usually biased. In clinical research, covariates measured without error such as treatment procedure or sex are often used in conjunction with a covariate measured with error. In a randomized clinical trial of two types of treatments, we account for the measurement error in the covariate, log-transformed total rapid eye movement (REM) activity counts, in a Cox model analysis of the time to recurrence of major depression in an elderly population. Regression calibration and two variants of a likelihood-based approach are used to account for measurement error. The likelihood-based approach is extended to account for the correlation between replicate measures of the covariate. Using the replicate data decreases the standard error of the parameter estimate for log(total REM) counts while maintaining the bias reduction of the estimate. We conclude that covariate measurement error and the correlation between replicates can affect results in a Cox model analysis and should be accounted for. In the depression data, these methods render comparable results that have less bias than the results when measurement error is ignored.
Jongen, T.; Machiels, L.; Gatski, T. B.
1997-01-01
Three types of turbulence models which account for rotational effects in noninertial frames of reference are evaluated for the case of incompressible, fully developed rotating turbulent channel flow. The different types of models are a Coriolis-modified eddy-viscosity model, a realizable algebraic stress model, and an algebraic stress model which accounts for dissipation rate anisotropies. A direct numerical simulation of a rotating channel flow is used for the turbulent model validation. This simulation differs from previous studies in that significantly higher rotation numbers are investigated. Flows at these higher rotation numbers are characterized by a relaminarization on the cyclonic or suction side of the channel, and a linear velocity profile on the anticyclonic or pressure side of the channel. The predictive performance of the three types of models are examined in detail, and formulation deficiencies are identified which cause poor predictive performance for some of the models. Criteria are identified which allow for accurate prediction of such flows by algebraic stress models and their corresponding Reynolds stress formulations.
Accounting for Local Dependence with the Rasch Model: The Paradox of Information Increase.
Andrich, David
Test theories imply statistical, local independence. Where local independence is violated, models of modern test theory that account for it have been proposed. One violation of local independence occurs when the response to one item governs the response to a subsequent item. Expanding on a formulation of this kind of violation between two items in the dichotomous Rasch model, this paper derives three related implications. First, it formalises how the polytomous Rasch model for an item constituted by summing the scores of the dependent items absorbs the dependence in its threshold structure. Second, it shows that as a consequence the unit when the dependence is accounted for is not the same as if the items had no response dependence. Third, it explains the paradox, known, but not explained in the literature, that the greater the dependence of the constituent items the greater the apparent information in the constituted polytomous item when it should provide less information.
Cost accounting models used for price-setting of health services: an international review.
Raulinajtys-Grzybek, Monika
2014-12-01
The aim of the article was to present and compare cost accounting models which are used in the area of healthcare for pricing purposes in different countries. Cost information generated by hospitals is further used by regulatory bodies for setting or updating prices of public health services. The article presents a set of examples from different countries of the European Union, Australia and the United States and concentrates on DRG-based payment systems as they primarily use cost information for pricing. Differences between countries concern the methodology used, as well as the data collection process and the scope of the regulations on cost accounting. The article indicates that the accuracy of the calculation is only one of the factors that determine the choice of the cost accounting methodology. Important aspects are also the selection of the reference hospitals, precise and detailed regulations and the existence of complex healthcare information systems in hospitals. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Accounting for sex differences in PTSD: A multi-variable mediation model
DEFF Research Database (Denmark)
Christiansen, Dorte M.; Hansen, Maj
2015-01-01
methods that were not ideally suited to test for mediation effects. Prior research has identified a number of individual risk factors that may contribute to sex differences in PTSD severity, although these cannot fully account for the increased symptom levels in females when examined individually....... Objective: The present study is the first to systematically test the hypothesis that a combination of pre-, peri-, and posttraumatic risk factors more prevalent in females can account for sex differences in PTSD severity. Method: The study was a quasi-prospective questionnaire survey assessing PTSD...... cognitions about self and the world, and feeling let down. These variables were included in the model as potential mediators. The combination of risk factors significantly mediated the association between sex and PTSD severity, accounting for 83% of the association. Conclusion: The findings suggest...
Bilcke, Joke; Beutels, Philippe; Brisson, Marc; Jit, Mark
2011-01-01
Accounting for uncertainty is now a standard part of decision-analytic modeling and is recommended by many health technology agencies and published guidelines. However, the scope of such analyses is often limited, even though techniques have been developed for presenting the effects of methodological, structural, and parameter uncertainty on model results. To help bring these techniques into mainstream use, the authors present a step-by-step guide that offers an integrated approach to account for different kinds of uncertainty in the same model, along with a checklist for assessing the way in which uncertainty has been incorporated. The guide also addresses special situations such as when a source of uncertainty is difficult to parameterize, resources are limited for an ideal exploration of uncertainty, or evidence to inform the model is not available or not reliable. for identifying the sources of uncertainty that influence results most are also described. Besides guiding analysts, the guide and checklist may be useful to decision makers who need to assess how well uncertainty has been accounted for in a decision-analytic model before using the results to make a decision.
Modeling of Accounting Doctoral Thesis with Emphasis on Solution for Financial Problems
Directory of Open Access Journals (Sweden)
F. Mansoori
2015-02-01
Full Text Available By passing the instruction period and increase of graduate students and also research budget, knowledge of accounting in Iran entered to the field of research in a way that number of accounting projects has been implemented in the real world. Because of that different experience in implementing the accounting standards were achieved. So, it was expected the mentioned experiences help to solve the financial problems in country, in spite of lots of efforts which were done for researching; we still have many financial and accounting problems in our country. PHD projects could be considered as one of the important solutions to improve the University subjects including accounting. PHD projects are considered as team work job and it will be legitimate by supervisor teams in universities.It is obvious that applied projects should solve part of the problems in accounting field but unfortunately it is not working in the real world. The question which came in to our mind is how come that the out put of the applied and knowledge base projects could not make the darkness of the mentioned problems clear and also why politicians in difficult situations prefer to use their own previous experiences in important decision makings instead of using the consultant’s knowledge base suggestions.In this research I’m going to study, the reasons behind that prevent the applied PHD projects from success in real world which relates to the point of view that consider the political suggestions which are out put of knowledge base projects are not qualified enough for implementation. For this purpose, the indicators of an applied PHD project were considered and 110 vise people were categorized the mentioned indicators and then in a comprehensive study other applied PHD accounting projects were compared to each other.As result, in this study problems of the studied researches were identified and a proper and applied model for creating applied research was developed.
Accounting for measurement error in log regression models with applications to accelerated testing.
Directory of Open Access Journals (Sweden)
Robert Richardson
Full Text Available In regression settings, parameter estimates will be biased when the explanatory variables are measured with error. This bias can significantly affect modeling goals. In particular, accelerated lifetime testing involves an extrapolation of the fitted model, and a small amount of bias in parameter estimates may result in a significant increase in the bias of the extrapolated predictions. Additionally, bias may arise when the stochastic component of a log regression model is assumed to be multiplicative when the actual underlying stochastic component is additive. To account for these possible sources of bias, a log regression model with measurement error and additive error is approximated by a weighted regression model which can be estimated using Iteratively Re-weighted Least Squares. Using the reduced Eyring equation in an accelerated testing setting, the model is compared to previously accepted approaches to modeling accelerated testing data with both simulations and real data.
Accounting for measurement error in log regression models with applications to accelerated testing.
Richardson, Robert; Tolley, H Dennis; Evenson, William E; Lunt, Barry M
2018-01-01
In regression settings, parameter estimates will be biased when the explanatory variables are measured with error. This bias can significantly affect modeling goals. In particular, accelerated lifetime testing involves an extrapolation of the fitted model, and a small amount of bias in parameter estimates may result in a significant increase in the bias of the extrapolated predictions. Additionally, bias may arise when the stochastic component of a log regression model is assumed to be multiplicative when the actual underlying stochastic component is additive. To account for these possible sources of bias, a log regression model with measurement error and additive error is approximated by a weighted regression model which can be estimated using Iteratively Re-weighted Least Squares. Using the reduced Eyring equation in an accelerated testing setting, the model is compared to previously accepted approaches to modeling accelerated testing data with both simulations and real data.
The self-consistent field model for Fermi systems with account of three-body interactions
Directory of Open Access Journals (Sweden)
Yu.M. Poluektov
2015-12-01
Full Text Available On the basis of a microscopic model of self-consistent field, the thermodynamics of the many-particle Fermi system at finite temperatures with account of three-body interactions is built and the quasiparticle equations of motion are obtained. It is shown that the delta-like three-body interaction gives no contribution into the self-consistent field, and the description of three-body forces requires their nonlocality to be taken into account. The spatially uniform system is considered in detail, and on the basis of the developed microscopic approach general formulas are derived for the fermion's effective mass and the system's equation of state with account of contribution from three-body forces. The effective mass and pressure are numerically calculated for the potential of "semi-transparent sphere" type at zero temperature. Expansions of the effective mass and pressure in powers of density are obtained. It is shown that, with account of only pair forces, the interaction of repulsive character reduces the quasiparticle effective mass relative to the mass of a free particle, and the attractive interaction raises the effective mass. The question of thermodynamic stability of the Fermi system is considered and the three-body repulsive interaction is shown to extend the region of stability of the system with the interparticle pair attraction. The quasiparticle energy spectrum is calculated with account of three-body forces.
Rigor in Qualitative Supply Chain Management Research
DEFF Research Database (Denmark)
Goffin, Keith; Raja, Jawwad; Claes, Björn
2012-01-01
, reliability, and theoretical saturation. Originality/value – It is the authors' contention that the addition of the repertory grid technique to the toolset of methods used by logistics and supply chain management researchers can only enhance insights and the building of robust theories. Qualitative studies......Purpose – The purpose of this paper is to share the authors' experiences of using the repertory grid technique in two supply chain management studies. The paper aims to demonstrate how the two studies provided insights into how qualitative techniques such as the repertory grid can be made more...... rigorous than in the past, and how results can be generated that are inaccessible using quantitative methods. Design/methodology/approach – This paper presents two studies undertaken using the repertory grid technique to illustrate its application in supply chain management research. Findings – The paper...
Statistics for mathematicians a rigorous first course
Panaretos, Victor M
2016-01-01
This textbook provides a coherent introduction to the main concepts and methods of one-parameter statistical inference. Intended for students of Mathematics taking their first course in Statistics, the focus is on Statistics for Mathematicians rather than on Mathematical Statistics. The goal is not to focus on the mathematical/theoretical aspects of the subject, but rather to provide an introduction to the subject tailored to the mindset and tastes of Mathematics students, who are sometimes turned off by the informal nature of Statistics courses. This book can be used as the basis for an elementary semester-long first course on Statistics with a firm sense of direction that does not sacrifice rigor. The deeper goal of the text is to attract the attention of promising Mathematics students.
Two-species occupancy modeling accounting for species misidentification and nondetection
Chambert, Thierry; Grant, Evan H. Campbell; Miller, David A. W.; Nichols, James; Mulder, Kevin P.; Brand, Adrianne B,
2018-01-01
1. In occupancy studies, species misidentification can lead to false positive detections, which can cause severe estimator biases. Currently, all models that account for false positive errors only consider omnibus sources of false detections and are limited to single species occupancy. 2. However, false detections for a given species often occur because of the misidentification with another, closely-related species. To exploit this explicit source of false positive detection error, we develop a two-species occupancy model that accounts for misidentifications between two species of interest. As with other false positive models, identifiability is greatly improved by the availability of unambiguous detections at a subset of site-occasions. Here, we consider the case where some of the field observations can be confirmed using laboratory or other independent identification methods (“confirmatory data”). 3. We performed three simulation studies to (1) assess the model’s performance under various realistic scenarios, (2) investigate the influence of the proportion of confirmatory data on estimator accuracy, and (3) compare the performance of this two-species model with that of the single-species false positive model. The model shows good performance under all scenarios, even when only small proportions of detections are confirmed (e.g., 5%). It also clearly outperforms the single-species model.
A methodology for the rigorous verification of plasma simulation codes
Riva, Fabio
2016-10-01
The methodology used to assess the reliability of numerical simulation codes constitutes the Verification and Validation (V&V) procedure. V&V is composed by two separate tasks: the verification, which is a mathematical issue targeted to assess that the physical model is correctly solved, and the validation, which determines the consistency of the code results, and therefore of the physical model, with experimental data. In the present talk we focus our attention on the verification, which in turn is composed by the code verification, targeted to assess that a physical model is correctly implemented in a simulation code, and the solution verification, that quantifies the numerical error affecting a simulation. Bridging the gap between plasma physics and other scientific domains, we introduced for the first time in our domain a rigorous methodology for the code verification, based on the method of manufactured solutions, as well as a solution verification based on the Richardson extrapolation. This methodology was applied to GBS, a three-dimensional fluid code based on a finite difference scheme, used to investigate the plasma turbulence in basic plasma physics experiments and in the tokamak scrape-off layer. Overcoming the difficulty of dealing with a numerical method intrinsically affected by statistical noise, we have now generalized the rigorous verification methodology to simulation codes based on the particle-in-cell algorithm, which are employed to solve Vlasov equation in the investigation of a number of plasma physics phenomena.
Analysis of the microscopic model taking into account of the 2p2h configurations
International Nuclear Information System (INIS)
Kamerdzhiev, S.P.; Tkachev, V.N.
1986-01-01
A general equation for the effective field inside the nucleus, which takes into account both 1p1h and 2p2h configurations, is derived by the Green function method. This equation is used as a starting point to derive the previously developed microscopic model for account of the > configurations in magic nuclei. The equations for the density matrix are analyzed in this model. It is shown that the quasiparticle number conservation law is valid. The equation for the effective field is written in the coordinate representation. As a result, the problem acquires the formulation in the > approximation. The equation in the space of one-phonon states is derived and quantitatively analyzed
Analysis of a microscopic model of taking into account 2p2h configurations
International Nuclear Information System (INIS)
Kamerdzhiev, S.P.; Tkachev, V.N.
1986-01-01
The Green's-function method has been used to obtain a general equation for the effective field in a nucleus, taking into account both 1p1h and 2p2h configurations. This equation has been used as the starting point for derivation of a previously developed microscopic model of taking 1p1h+phonon configurations into account in magic nuclei. The equation for the density matrix is analyzed in this model. It is shown that the number of quasiparticles is conserved. An equation is obtained for the effective field in the coordinate representation, which provides a formulation of the problem in the 1p1h+2p2h+continuum approximation. The equation is derived and quantitatively analyzed in the space of one-phonon states
A Simple Accounting-based Valuation Model for the Debt Tax Shield
Directory of Open Access Journals (Sweden)
Andreas Scholze
2010-05-01
Full Text Available This paper describes a simple way to integrate the debt tax shield into an accounting-based valuation model. The market value of equity is determined by forecasting residual operating income, which is calculated by charging operating income for the operating assets at a required return that accounts for the tax benefit that comes from borrowing to raise cash for the operations. The model assumes that the firm maintains a deterministic financial leverage ratio, which tends to converge quickly to typical steady-state levels over time. From a practical point of view, this characteristic is of particular help, because it allows a continuing value calculation at the end of a short forecast period.
Zipkin, Elise F.; Grant, Evan H. Campbell; Fagan, William F.
2012-01-01
The ability to accurately predict patterns of species' occurrences is fundamental to the successful management of animal communities. To determine optimal management strategies, it is essential to understand species-habitat relationships and how species habitat use is related to natural or human-induced environmental changes. Using five years of monitoring data in the Chesapeake and Ohio Canal National Historical Park, Maryland, USA, we developed four multi-species hierarchical models for estimating amphibian wetland use that account for imperfect detection during sampling. The models were designed to determine which factors (wetland habitat characteristics, annual trend effects, spring/summer precipitation, and previous wetland occupancy) were most important for predicting future habitat use. We used the models to make predictions of species occurrences in sampled and unsampled wetlands and evaluated model projections using additional data. Using a Bayesian approach, we calculated a posterior distribution of receiver operating characteristic area under the curve (ROC AUC) values, which allowed us to explicitly quantify the uncertainty in the quality of our predictions and to account for false negatives in the evaluation dataset. We found that wetland hydroperiod (the length of time that a wetland holds water) as well as the occurrence state in the prior year were generally the most important factors in determining occupancy. The model with only habitat covariates predicted species occurrences well; however, knowledge of wetland use in the previous year significantly improved predictive ability at the community level and for two of 12 species/species complexes. Our results demonstrate the utility of multi-species models for understanding which factors affect species habitat use of an entire community (of species) and provide an improved methodology using AUC that is helpful for quantifying the uncertainty in model predictions while explicitly accounting for
An enhanced temperature index model for debris-covered glaciers accounting for thickness effect
Carenzo, M.; Pellicciotti, F.; Mabillard, J.; Reid, T.; Brock, B. W.
2016-08-01
Debris-covered glaciers are increasingly studied because it is assumed that debris cover extent and thickness could increase in a warming climate, with more regular rockfalls from the surrounding slopes and more englacial melt-out material. Debris energy-balance models have been developed to account for the melt rate enhancement/reduction due to a thin/thick debris layer, respectively. However, such models require a large amount of input data that are not often available, especially in remote mountain areas such as the Himalaya, and can be difficult to extrapolate. Due to their lower data requirements, empirical models have been used extensively in clean glacier melt modelling. For debris-covered glaciers, however, they generally simplify the debris effect by using a single melt-reduction factor which does not account for the influence of varying debris thickness on melt and prescribe a constant reduction for the entire melt across a glacier. In this paper, we present a new temperature-index model that accounts for debris thickness in the computation of melt rates at the debris-ice interface. The model empirical parameters are optimized at the point scale for varying debris thicknesses against melt rates simulated by a physically-based debris energy balance model. The latter is validated against ablation stake readings and surface temperature measurements. Each parameter is then related to a plausible set of debris thickness values to provide a general and transferable parameterization. We develop the model on Miage Glacier, Italy, and then test its transferability on Haut Glacier d'Arolla, Switzerland. The performance of the new debris temperature-index (DETI) model in simulating the glacier melt rate at the point scale is comparable to the one of the physically based approach, and the definition of model parameters as a function of debris thickness allows the simulation of the nonlinear relationship of melt rate to debris thickness, summarised by the
Models and error analyses of measuring instruments in accountability systems in safeguards control
International Nuclear Information System (INIS)
Dattatreya, E.S.
1977-05-01
Essentially three types of measuring instruments are used in plutonium accountability systems: (1) the bubblers, for measuring the total volume of liquid in the holding tanks, (2) coulometers, titration apparatus and calorimeters, for measuring the concentration of plutonium; and (3) spectrometers, for measuring isotopic composition. These three classes of instruments are modeled and analyzed. Finally, the uncertainty in the estimation of total plutonium in the holding tank is determined
[Application of detecting and taking overdispersion into account in Poisson regression model].
Bouche, G; Lepage, B; Migeot, V; Ingrand, P
2009-08-01
Researchers often use the Poisson regression model to analyze count data. Overdispersion can occur when a Poisson regression model is used, resulting in an underestimation of variance of the regression model parameters. Our objective was to take overdispersion into account and assess its impact with an illustration based on the data of a study investigating the relationship between use of the Internet to seek health information and number of primary care consultations. Three methods, overdispersed Poisson, a robust estimator, and negative binomial regression, were performed to take overdispersion into account in explaining variation in the number (Y) of primary care consultations. We tested overdispersion in the Poisson regression model using the ratio of the sum of Pearson residuals over the number of degrees of freedom (chi(2)/df). We then fitted the three models and compared parameter estimation to the estimations given by Poisson regression model. Variance of the number of primary care consultations (Var[Y]=21.03) was greater than the mean (E[Y]=5.93) and the chi(2)/df ratio was 3.26, which confirmed overdispersion. Standard errors of the parameters varied greatly between the Poisson regression model and the three other regression models. Interpretation of estimates from two variables (using the Internet to seek health information and single parent family) would have changed according to the model retained, with significant levels of 0.06 and 0.002 (Poisson), 0.29 and 0.09 (overdispersed Poisson), 0.29 and 0.13 (use of a robust estimator) and 0.45 and 0.13 (negative binomial) respectively. Different methods exist to solve the problem of underestimating variance in the Poisson regression model when overdispersion is present. The negative binomial regression model seems to be particularly accurate because of its theorical distribution ; in addition this regression is easy to perform with ordinary statistical software packages.
International Nuclear Information System (INIS)
Sicherman, A.; Fortney, D.S.; Patenaude, C.J.
1993-07-01
DOE Material Control and Accountability Order 5633.3A requires that facilities handling special nuclear material evaluate their effectiveness against protracted theft (repeated thefts of small quantities of material, typically occurring over an extended time frame, to accumulate a goal quantity). Because a protracted theft attempt can extend over time, material accountability-like (MA) safeguards may help detect a protracted theft attempt in progress. Inventory anomalies, and material not in its authorized location when requested for processing are examples of MA detection mechanisms. Crediting such detection in evaluations, however, requires taking into account potential insider subversion of MA safeguards. In this paper, the authors describe a database model for evaluating MA safeguards effectiveness against protracted theft that addresses potential subversion. The model includes a detailed yet practical structure for characterizing various types of MA activities, lists of potential insider MA defeat methods and access/authority related to MA activities, and an initial implementation of built-in MA detection probabilities. This database model, implemented in the new Protracted Insider module of ASSESS (Analytic System and Software for Evaluating Safeguards and Security), helps facilitate the systematic collection of relevant information about MA activity steps, and ''standardize'' MA safeguards evaluations
Mbawuni, Joseph; Nimako, Simon Gyasi
2015-01-01
This study principally investigates job-related and personality factors that determine Ghanaian accounting students' intentions to pursue careers in accounting. It draws on a rich body of existing literature to develop a research model. Primary data were collected from a cross-sectional survey of 516 final year accounting students in a Ghanaian…
INVESTIGATION INTO ACCOUNT OF A TIME VALUE OF MONEY IN CLASSICAL MULTITOPIC INVENTORY MODELS
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Natalya A. Chernyaeva
2013-01-01
Full Text Available The article describes two types of models. The first is a traditional multitopic inventory model with constant demand and the second is a model based on the average cost of inventory in optimizing inventory management system. The authors taking into account the time value of money in the models study three possible schemes for the payment of costs: «prenumerando» (at the time of the general batch order delivery, «postnumerando» (at the time of the general next batch order delivery and the scheme of payment of costs in the mid-term.Maximization of the total intensity of revenue for outgoing and incoming cash flows occurring in the inventory management system that characterize the analyzed models was adopted as the criterion of optimization of inventory control strategy.
A multiscale active structural model of the arterial wall accounting for smooth muscle dynamics.
Coccarelli, Alberto; Edwards, David Hughes; Aggarwal, Ankush; Nithiarasu, Perumal; Parthimos, Dimitris
2018-02-01
Arterial wall dynamics arise from the synergy of passive mechano-elastic properties of the vascular tissue and the active contractile behaviour of smooth muscle cells (SMCs) that form the media layer of vessels. We have developed a computational framework that incorporates both these components to account for vascular responses to mechanical and pharmacological stimuli. To validate the proposed framework and demonstrate its potential for testing hypotheses on the pathogenesis of vascular disease, we have employed a number of pharmacological probes that modulate the arterial wall contractile machinery by selectively inhibiting a range of intracellular signalling pathways. Experimental probes used on ring segments from the rabbit central ear artery are: phenylephrine, a selective α 1-adrenergic receptor agonist that induces vasoconstriction; cyclopiazonic acid (CPA), a specific inhibitor of sarcoplasmic/endoplasmic reticulum Ca 2+ -ATPase; and ryanodine, a diterpenoid that modulates Ca 2+ release from the sarcoplasmic reticulum. These interventions were able to delineate the role of membrane versus intracellular signalling, previously identified as main factors in smooth muscle contraction and the generation of vessel tone. Each SMC was modelled by a system of nonlinear differential equations that account for intracellular ionic signalling, and in particular Ca 2+ dynamics. Cytosolic Ca 2+ concentrations formed the catalytic input to a cross-bridge kinetics model. Contractile output from these cellular components forms the input to the finite-element model of the arterial rings under isometric conditions that reproduces the experimental conditions. The model does not account for the role of the endothelium, as the nitric oxide production was suppressed by the action of L-NAME, and also due to the absence of shear stress on the arterial ring, as the experimental set-up did not involve flow. Simulations generated by the integrated model closely matched experimental
Model of inventory replenishment in periodic review accounting for the occurrence of shortages
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Stanisław Krzyżaniak
2014-03-01
Full Text Available Background: Despite the development of alternative concepts of goods flow management, the inventory management under conditions of random variations of demand is still an important issue, both from the point of view of inventory keeping and replenishment costs and the service level measured as the level of inventory availability. There is a number of inventory replenishment systems used in these conditions, but they are mostly developments of two basic systems: reorder point-based and periodic review-based. The paper deals with the latter system. Numerous researches indicate the need to improve the classical models describing that system, the reason being mainly the necessity to adapt the model better to the actual conditions. This allows a correct selection of parameters that control the used inventory replenishment system and - as a result - to obtain expected economic effects. Methods: This research aimed at building a model of the periodic review system to reflect the relations (observed during simulation tests between the volume of inventory shortages and the degree of accounting for so-called deferred demand, and the service level expressed as the probability of satisfying the demand in the review and the inventory replenishment cycle. The following model building and testing method has been applied: numerical simulation of inventory replenishment - detailed analysis of simulation results - construction of the model taking into account the regularities observed during the simulations - determination of principles of solving the system of relations creating the model - verification of the results obtained from the model using the results from simulation. Results: Presented are selected results of calculations based on classical formulas and using the developed model, which describe the relations between the service level and the parameters controlling the discussed inventory replenishment system. The results are compared to the simulation
Testing the limits of the 'joint account' model of genetic information: a legal thought experiment.
Foster, Charles; Herring, Jonathan; Boyd, Magnus
2015-05-01
We examine the likely reception in the courtroom of the 'joint account' model of genetic confidentiality. We conclude that the model, as modified by Gilbar and others, is workable and reflects, better than more conventional legal approaches, both the biological and psychological realities and the obligations owed under Articles 8 and 10 of the European Convention on Human Rights (ECHR). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
Generation of SEEAW asset accounts based on water resources management models
Pedro-Monzonís, María; Solera, Abel; Andreu, Joaquín
2015-04-01
One of the main challenges in the XXI century is related with the sustainable use of water. This is due to the fact that water is an essential element for the life of all who inhabit our planet. In many cases, the lack of economic valuation of water resources causes an inefficient water use. In this regard, society expects of policymakers and stakeholders maximise the profit produced per unit of natural resources. Water planning and the Integrated Water Resources Management (IWRM) represent the best way to achieve this goal. The System of Environmental-Economic Accounting for Water (SEEAW) is displayed as a tool for water allocation which enables the building of water balances in a river basin. The main concern of the SEEAW is to provide a standard approach which allows the policymakers to compare results between different territories. But building water accounts is a complex task due to the difficulty of the collection of the required data. Due to the difficulty of gauging the components of the hydrological cycle, the use of simulation models has become an essential tool extensively employed in last decades. The target of this paper is to present the building up of a database that enables the combined use of hydrological models and water resources models developed with AQUATOOL DSSS to fill in the SEEAW tables. This research is framed within the Water Accounting in a Multi-Catchment District (WAMCD) project, financed by the European Union. Its main goal is the development of water accounts in the Mediterranean Andalusian River Basin District, in Spain. This research pretends to contribute to the objectives of the "Blueprint to safeguard Europe's water resources". It is noteworthy that, in Spain, a large part of these methodological decisions are included in the Spanish Guideline of Water Planning with normative status guaranteeing consistency and comparability of the results.
@AACAnatomy twitter account goes live: A sustainable social media model for professional societies.
Benjamin, Hannah K; Royer, Danielle F
2018-05-01
Social media, with its capabilities of fast, global information sharing, provides a useful medium for professional development, connecting and collaborating with peers, and outreach. The goals of this study were to describe a new, sustainable model for Twitter use by professional societies, and analyze its impact on @AACAnatomy, the Twitter account of the American Association of Clinical Anatomists. Under supervision of an Association committee member, an anatomy graduate student developed a protocol for publishing daily tweets for @AACAnatomy. Five tweet categories were used: Research, Announcements, Replies, Engagement, and Community. Analytics from the 6-month pilot phase were used to assess the impact of the new model. @AACAnatomy had a steady average growth of 33 new followers per month, with less than 10% likely representing Association members. Research tweets, based on Clinical Anatomy articles with an abstract link, were the most shared, averaging 5,451 impressions, 31 link clicks, and nine #ClinAnat hashtag clicks per month. However, tweets from non-Research categories accounted for the highest impression and engagement metrics in four out of six months. For all tweet categories, monthly averages show consistent interaction of followers with the account. Daily tweet publication resulted in a 103% follower increase. An active Twitter account successfully facilitated regular engagement with @AACAnatomy followers and the promotion of clinical anatomy topics within a broad community. This Twitter model has the potential for implementation by other societies as a sustainable medium for outreach, networking, collaboration, and member engagement. Clin. Anat. 31:566-575, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Lehar, Steven
2003-01-01
Visual illusions and perceptual grouping phenomena offer an invaluable tool for probing the computational mechanism of low-level visual processing. Some illusions, like the Kanizsa figure, reveal illusory contours that form edges collinear with the inducing stimulus. This kind of illusory contour has been modeled by neural network models by way of cells equipped with elongated spatial receptive fields designed to detect and complete the collinear alignment. There are, however, other illusory groupings which are not so easy to account for in neural network terms. The Ehrenstein illusion exhibits an illusory contour that forms a contour orthogonal to the stimulus instead of collinear with it. Other perceptual grouping effects reveal illusory contours that exhibit a sharp corner or vertex, and still others take the form of vertices defined by the intersection of three, four, or more illusory contours that meet at a point. A direct extension of the collinear completion models to account for these phenomena tends towards a combinatorial explosion, because it would suggest cells with specialized receptive fields configured to perform each of those completion types, each of which would have to be replicated at every location and every orientation across the visual field. These phenomena therefore challenge the adequacy of the neural network approach to account for these diverse perceptual phenomena. I have proposed elsewhere an alternative paradigm of neurocomputation in the harmonic resonance theory (Lehar 1999, see website), whereby pattern recognition and completion are performed by spatial standing waves across the neural substrate. The standing waves perform a computational function analogous to that of the spatial receptive fields of the neural network approach, except that, unlike that paradigm, a single resonance mechanism performs a function equivalent to a whole array of spatial receptive fields of different spatial configurations and of different orientations
A Buffer Model Account of Behavioral and ERP Patterns in the Von Restorff Paradigm
Directory of Open Access Journals (Sweden)
Siri-Maria Kamp
2016-06-01
Full Text Available We combined a mechanistic model of episodic encoding with theories on the functional significance of two event-related potential (ERP components to develop an integrated account for the Von Restorff effect, which refers to the enhanced recall probability for an item that deviates in some feature from other items in its study list. The buffer model of Lehman and Malmberg (2009, 2013 can account for this effect such that items encountered during encoding enter an episodic buffer where they are actively rehearsed. When a deviant item is encountered, in order to re-allocate encoding resources towards this item the buffer is emptied from its prior content, a process labeled “compartmentalization”. Based on theories on their functional significance, the P300 component of the ERP may co-occur with this hypothesized compartmentalization process, while the frontal slow wave may index rehearsal. We derived predictions from this integrated model for output patterns in free recall, systematic variance in ERP components, as well as associations between the two types of measures in a dataset of 45 participants who studied and freely recalled lists of the Von Restorff type. Our major predictions were confirmed and the behavioral and physiological results were consistent with the predictions derived from the model. These findings demonstrate that constraining mechanistic models of episodic memory with brain activity patterns and generating predictions for relationships between brain activity and behavior can lead to novel insights into the relationship between the brain, the mind, and behavior.
Accounting for standard errors of vision-specific latent trait in regression models.
Wong, Wan Ling; Li, Xiang; Li, Jialiang; Wong, Tien Yin; Cheng, Ching-Yu; Lamoureux, Ecosse L
2014-07-11
To demonstrate the effectiveness of Hierarchical Bayesian (HB) approach in a modeling framework for association effects that accounts for SEs of vision-specific latent traits assessed using Rasch analysis. A systematic literature review was conducted in four major ophthalmic journals to evaluate Rasch analysis performed on vision-specific instruments. The HB approach was used to synthesize the Rasch model and multiple linear regression model for the assessment of the association effects related to vision-specific latent traits. The effectiveness of this novel HB one-stage "joint-analysis" approach allows all model parameters to be estimated simultaneously and was compared with the frequently used two-stage "separate-analysis" approach in our simulation study (Rasch analysis followed by traditional statistical analyses without adjustment for SE of latent trait). Sixty-six reviewed articles performed evaluation and validation of vision-specific instruments using Rasch analysis, and 86.4% (n = 57) performed further statistical analyses on the Rasch-scaled data using traditional statistical methods; none took into consideration SEs of the estimated Rasch-scaled scores. The two models on real data differed for effect size estimations and the identification of "independent risk factors." Simulation results showed that our proposed HB one-stage "joint-analysis" approach produces greater accuracy (average of 5-fold decrease in bias) with comparable power and precision in estimation of associations when compared with the frequently used two-stage "separate-analysis" procedure despite accounting for greater uncertainty due to the latent trait. Patient-reported data, using Rasch analysis techniques, do not take into account the SE of latent trait in association analyses. The HB one-stage "joint-analysis" is a better approach, producing accurate effect size estimations and information about the independent association of exposure variables with vision-specific latent traits
Rolland, N; Larson, D J; Geiser, B P; Duguay, S; Vurpillot, F; Blavette, D
2015-12-01
An analytical model describing the field evaporation dynamics of a tip made of a thin layer deposited on a substrate is presented in this paper. The difference in evaporation field between the materials is taken into account in this approach in which the tip shape is modeled at a mesoscopic scale. It was found that the non-existence of sharp edge on the surface is a sufficient condition to derive the morphological evolution during successive evaporation of the layers. This modeling gives an instantaneous and smooth analytical representation of the surface that shows good agreement with finite difference simulations results, and a specific regime of evaporation was highlighted when the substrate is a low evaporation field phase. In addition, the model makes it possible to calculate theoretically the tip analyzed volume, potentially opening up new horizons for atom probe tomographic reconstruction. Copyright © 2015 Elsevier B.V. All rights reserved.
Spectral Neugebauer-based color halftone prediction model accounting for paper fluorescence.
Hersch, Roger David
2014-08-20
We present a spectral model for predicting the fluorescent emission and the total reflectance of color halftones printed on optically brightened paper. By relying on extended Neugebauer models, the proposed model accounts for the attenuation by the ink halftones of both the incident exciting light in the UV wavelength range and the emerging fluorescent emission in the visible wavelength range. The total reflectance is predicted by adding the predicted fluorescent emission relative to the incident light and the pure reflectance predicted with an ink-spreading enhanced Yule-Nielsen modified Neugebauer reflectance prediction model. The predicted fluorescent emission spectrum as a function of the amounts of cyan, magenta, and yellow inks is very accurate. It can be useful to paper and ink manufacturers who would like to study in detail the contribution of the fluorescent brighteners and the attenuation of the fluorescent emission by ink halftones.
Rigorous theory of molecular orientational nonlinear optics
International Nuclear Information System (INIS)
Kwak, Chong Hoon; Kim, Gun Yeup
2015-01-01
Classical statistical mechanics of the molecular optics theory proposed by Buckingham [A. D. Buckingham and J. A. Pople, Proc. Phys. Soc. A 68, 905 (1955)] has been extended to describe the field induced molecular orientational polarization effects on nonlinear optics. In this paper, we present the generalized molecular orientational nonlinear optical processes (MONLO) through the calculation of the classical orientational averaging using the Boltzmann type time-averaged orientational interaction energy in the randomly oriented molecular system under the influence of applied electric fields. The focal points of the calculation are (1) the derivation of rigorous tensorial components of the effective molecular hyperpolarizabilities, (2) the molecular orientational polarizations and the electronic polarizations including the well-known third-order dc polarization, dc electric field induced Kerr effect (dc Kerr effect), optical Kerr effect (OKE), dc electric field induced second harmonic generation (EFISH), degenerate four wave mixing (DFWM) and third harmonic generation (THG). We also present some of the new predictive MONLO processes. For second-order MONLO, second-order optical rectification (SOR), Pockels effect and difference frequency generation (DFG) are described in terms of the anisotropic coefficients of first hyperpolarizability. And, for third-order MONLO, third-order optical rectification (TOR), dc electric field induced difference frequency generation (EFIDFG) and pump-probe transmission are presented
Regional Balance Model of Financial Flows through Sectoral Approaches System of National Accounts
Directory of Open Access Journals (Sweden)
Ekaterina Aleksandrovna Zaharchuk
2017-03-01
Full Text Available The main purpose of the study, the results of which are reflected in this article, is the theoretical and methodological substantiation of possibilities to build a regional balance model of financial flows consistent with the principles of the construction of the System of National Accounts (SNA. The paper summarizes the international experience of building regional accounts in the SNA as well as reflects the advantages and disadvantages of the existing techniques for constructing Social Accounting Matrix. The authors have proposed an approach to build the regional balance model of financial flows, which is based on the disaggregated tables of the formation, distribution and use of the added value of territory in the framework of institutional sectors of SNA (corporations, public administration, households. Within the problem resolution of the transition of value added from industries to sectors, the authors have offered an approach to the accounting of development, distribution and use of value added within the institutional sectors of the territories. The methods of calculation are based on the publicly available information base of statistics agencies and federal services. The authors provide the scheme of the interrelations of the indicators of the regional balance model of financial flows. It allows to coordinate mutually the movement of regional resources by the sectors of «corporation», «public administration» and «households» among themselves, and cash flows of the region — by the sectors and directions of use. As a result, they form a single account of the formation and distribution of territorial financial resources, which is a regional balance model of financial flows. This matrix shows the distribution of financial resources by income sources and sectors, where the components of the formation (compensation, taxes and gross profit, distribution (transfers and payments and use (final consumption, accumulation of value added are
Developing a tuberculosis transmission model that accounts for changes in population health.
Oxlade, Olivia; Schwartzman, Kevin; Benedetti, Andrea; Pai, Madhukar; Heymann, Jody; Menzies, Dick
2011-01-01
Simulation models are useful in policy planning for tuberculosis (TB) control. To accurately assess interventions, important modifiers of the epidemic should be accounted for in evaluative models. Improvements in population health were associated with the declining TB epidemic in the pre-antibiotic era and may be relevant today. The objective of this study was to develop and validate a TB transmission model that accounted for changes in population health. We developed a deterministic TB transmission model, using reported data from the pre-antibiotic era in England. Change in adjusted life expectancy, used as a proxy for general health, was used to determine the rate of change of key epidemiological parameters. Predicted outcomes included risk of TB infection and TB mortality. The model was validated in the setting of the Netherlands and then applied to modern Peru. The model, developed in the setting of England, predicted TB trends in the Netherlands very accurately. The R(2) value for correlation between observed and predicted data was 0.97 and 0.95 for TB infection and mortality, respectively. In Peru, the predicted decline in incidence prior to the expansion of "Directly Observed Treatment Short Course" (The DOTS strategy) was 3.7% per year (observed = 3.9% per year). After DOTS expansion, the predicted decline was very similar to the observed decline of 5.8% per year. We successfully developed and validated a TB model, which uses a proxy for population health to estimate changes in key epidemiology parameters. Population health contributed significantly to improvement in TB outcomes observed in Peru. Changing population health should be incorporated into evaluative models for global TB control.
Accounting for Zero Inflation of Mussel Parasite Counts Using Discrete Regression Models
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Emel Çankaya
2017-06-01
Full Text Available In many ecological applications, the absences of species are inevitable due to either detection faults in samples or uninhabitable conditions for their existence, resulting in high number of zero counts or abundance. Usual practice for modelling such data is regression modelling of log(abundance+1 and it is well know that resulting model is inadequate for prediction purposes. New discrete models accounting for zero abundances, namely zero-inflated regression (ZIP and ZINB, Hurdle-Poisson (HP and Hurdle-Negative Binomial (HNB amongst others are widely preferred to the classical regression models. Due to the fact that mussels are one of the economically most important aquatic products of Turkey, the purpose of this study is therefore to examine the performances of these four models in determination of the significant biotic and abiotic factors on the occurrences of Nematopsis legeri parasite harming the existence of Mediterranean mussels (Mytilus galloprovincialis L.. The data collected from the three coastal regions of Sinop city in Turkey showed more than 50% of parasite counts on the average are zero-valued and model comparisons were based on information criterion. The results showed that the probability of the occurrence of this parasite is here best formulated by ZINB or HNB models and influential factors of models were found to be correspondent with ecological differences of the regions.
A predictive coding account of bistable perception - a model-based fMRI study.
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Veith Weilnhammer
2017-05-01
Full Text Available In bistable vision, subjective perception wavers between two interpretations of a constant ambiguous stimulus. This dissociation between conscious perception and sensory stimulation has motivated various empirical studies on the neural correlates of bistable perception, but the neurocomputational mechanism behind endogenous perceptual transitions has remained elusive. Here, we recurred to a generic Bayesian framework of predictive coding and devised a model that casts endogenous perceptual transitions as a consequence of prediction errors emerging from residual evidence for the suppressed percept. Data simulations revealed close similarities between the model's predictions and key temporal characteristics of perceptual bistability, indicating that the model was able to reproduce bistable perception. Fitting the predictive coding model to behavioural data from an fMRI-experiment on bistable perception, we found a correlation across participants between the model parameter encoding perceptual stabilization and the behaviourally measured frequency of perceptual transitions, corroborating that the model successfully accounted for participants' perception. Formal model comparison with established models of bistable perception based on mutual inhibition and adaptation, noise or a combination of adaptation and noise was used for the validation of the predictive coding model against the established models. Most importantly, model-based analyses of the fMRI data revealed that prediction error time-courses derived from the predictive coding model correlated with neural signal time-courses in bilateral inferior frontal gyri and anterior insulae. Voxel-wise model selection indicated a superiority of the predictive coding model over conventional analysis approaches in explaining neural activity in these frontal areas, suggesting that frontal cortex encodes prediction errors that mediate endogenous perceptual transitions in bistable perception. Taken together
A predictive coding account of bistable perception - a model-based fMRI study.
Weilnhammer, Veith; Stuke, Heiner; Hesselmann, Guido; Sterzer, Philipp; Schmack, Katharina
2017-05-01
In bistable vision, subjective perception wavers between two interpretations of a constant ambiguous stimulus. This dissociation between conscious perception and sensory stimulation has motivated various empirical studies on the neural correlates of bistable perception, but the neurocomputational mechanism behind endogenous perceptual transitions has remained elusive. Here, we recurred to a generic Bayesian framework of predictive coding and devised a model that casts endogenous perceptual transitions as a consequence of prediction errors emerging from residual evidence for the suppressed percept. Data simulations revealed close similarities between the model's predictions and key temporal characteristics of perceptual bistability, indicating that the model was able to reproduce bistable perception. Fitting the predictive coding model to behavioural data from an fMRI-experiment on bistable perception, we found a correlation across participants between the model parameter encoding perceptual stabilization and the behaviourally measured frequency of perceptual transitions, corroborating that the model successfully accounted for participants' perception. Formal model comparison with established models of bistable perception based on mutual inhibition and adaptation, noise or a combination of adaptation and noise was used for the validation of the predictive coding model against the established models. Most importantly, model-based analyses of the fMRI data revealed that prediction error time-courses derived from the predictive coding model correlated with neural signal time-courses in bilateral inferior frontal gyri and anterior insulae. Voxel-wise model selection indicated a superiority of the predictive coding model over conventional analysis approaches in explaining neural activity in these frontal areas, suggesting that frontal cortex encodes prediction errors that mediate endogenous perceptual transitions in bistable perception. Taken together, our current work
Accounting for and predicting the influence of spatial autocorrelation in water quality modeling
Miralha, L.; Kim, D.
2017-12-01
Although many studies have attempted to investigate the spatial trends of water quality, more attention is yet to be paid to the consequences of considering and ignoring the spatial autocorrelation (SAC) that exists in water quality parameters. Several studies have mentioned the importance of accounting for SAC in water quality modeling, as well as the differences in outcomes between models that account for and ignore SAC. However, the capacity to predict the magnitude of such differences is still ambiguous. In this study, we hypothesized that SAC inherently possessed by a response variable (i.e., water quality parameter) influences the outcomes of spatial modeling. We evaluated whether the level of inherent SAC is associated with changes in R-Squared, Akaike Information Criterion (AIC), and residual SAC (rSAC), after accounting for SAC during modeling procedure. The main objective was to analyze if water quality parameters with higher Moran's I values (inherent SAC measure) undergo a greater increase in R² and a greater reduction in both AIC and rSAC. We compared a non-spatial model (OLS) to two spatial regression approaches (spatial lag and error models). Predictor variables were the principal components of topographic (elevation and slope), land cover, and hydrological soil group variables. We acquired these data from federal online sources (e.g. USGS). Ten watersheds were selected, each in a different state of the USA. Results revealed that water quality parameters with higher inherent SAC showed substantial increase in R² and decrease in rSAC after performing spatial regressions. However, AIC values did not show significant changes. Overall, the higher the level of inherent SAC in water quality variables, the greater improvement of model performance. This indicates a linear and direct relationship between the spatial model outcomes (R² and rSAC) and the degree of SAC in each water quality variable. Therefore, our study suggests that the inherent level of
Irving, J.; Koepke, C.; Elsheikh, A. H.
2017-12-01
Bayesian solutions to geophysical and hydrological inverse problems are dependent upon a forward process model linking subsurface parameters to measured data, which is typically assumed to be known perfectly in the inversion procedure. However, in order to make the stochastic solution of the inverse problem computationally tractable using, for example, Markov-chain-Monte-Carlo (MCMC) methods, fast approximations of the forward model are commonly employed. This introduces model error into the problem, which has the potential to significantly bias posterior statistics and hamper data integration efforts if not properly accounted for. Here, we present a new methodology for addressing the issue of model error in Bayesian solutions to hydrogeophysical inverse problems that is geared towards the common case where these errors cannot be effectively characterized globally through some parametric statistical distribution or locally based on interpolation between a small number of computed realizations. Rather than focusing on the construction of a global or local error model, we instead work towards identification of the model-error component of the residual through a projection-based approach. In this regard, pairs of approximate and detailed model runs are stored in a dictionary that grows at a specified rate during the MCMC inversion procedure. At each iteration, a local model-error basis is constructed for the current test set of model parameters using the K-nearest neighbour entries in the dictionary, which is then used to separate the model error from the other error sources before computing the likelihood of the proposed set of model parameters. We demonstrate the performance of our technique on the inversion of synthetic crosshole ground-penetrating radar traveltime data for three different subsurface parameterizations of varying complexity. The synthetic data are generated using the eikonal equation, whereas a straight-ray forward model is assumed in the inversion
Volume Holograms in Photopolymers: Comparison between Analytical and Rigorous Theories
Gallego, Sergi; Neipp, Cristian; Estepa, Luis A.; Ortuño, Manuel; Márquez, Andrés; Francés, Jorge; Pascual, Inmaculada; Beléndez, Augusto
2012-01-01
There is no doubt that the concept of volume holography has led to an incredibly great amount of scientific research and technological applications. One of these applications is the use of volume holograms as optical memories, and in particular, the use of a photosensitive medium like a photopolymeric material to record information in all its volume. In this work we analyze the applicability of Kogelnik’s Coupled Wave theory to the study of volume holograms recorded in photopolymers. Some of the theoretical models in the literature describing the mechanism of hologram formation in photopolymer materials use Kogelnik’s theory to analyze the gratings recorded in photopolymeric materials. If Kogelnik’s theory cannot be applied is necessary to use a more general Coupled Wave theory (CW) or the Rigorous Coupled Wave theory (RCW). The RCW does not incorporate any approximation and thus, since it is rigorous, permits judging the accurateness of the approximations included in Kogelnik’s and CW theories. In this article, a comparison between the predictions of the three theories for phase transmission diffraction gratings is carried out. We have demonstrated the agreement in the prediction of CW and RCW and the validity of Kogelnik’s theory only for gratings with spatial frequencies higher than 500 lines/mm for the usual values of the refractive index modulations obtained in photopolymers.
Volume Holograms in Photopolymers: Comparison between Analytical and Rigorous Theories
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Augusto Beléndez
2012-08-01
Full Text Available There is no doubt that the concept of volume holography has led to an incredibly great amount of scientific research and technological applications. One of these applications is the use of volume holograms as optical memories, and in particular, the use of a photosensitive medium like a photopolymeric material to record information in all its volume. In this work we analyze the applicability of Kogelnik’s Coupled Wave theory to the study of volume holograms recorded in photopolymers. Some of the theoretical models in the literature describing the mechanism of hologram formation in photopolymer materials use Kogelnik’s theory to analyze the gratings recorded in photopolymeric materials. If Kogelnik’s theory cannot be applied is necessary to use a more general Coupled Wave theory (CW or the Rigorous Coupled Wave theory (RCW. The RCW does not incorporate any approximation and thus, since it is rigorous, permits judging the accurateness of the approximations included in Kogelnik’s and CW theories. In this article, a comparison between the predictions of the three theories for phase transmission diffraction gratings is carried out. We have demonstrated the agreement in the prediction of CW and RCW and the validity of Kogelnik’s theory only for gratings with spatial frequencies higher than 500 lines/mm for the usual values of the refractive index modulations obtained in photopolymers.
Rigorous Results for the Distribution of Money on Connected Graphs
Lanchier, Nicolas; Reed, Stephanie
2018-05-01
This paper is concerned with general spatially explicit versions of three stochastic models for the dynamics of money that have been introduced and studied numerically by statistical physicists: the uniform reshuffling model, the immediate exchange model and the model with saving propensity. All three models consist of systems of economical agents that consecutively engage in pairwise monetary transactions. Computer simulations performed in the physics literature suggest that, when the number of agents and the average amount of money per agent are large, the limiting distribution of money as time goes to infinity approaches the exponential distribution for the first model, the gamma distribution with shape parameter two for the second model and a distribution similar but not exactly equal to a gamma distribution whose shape parameter depends on the saving propensity for the third model. The main objective of this paper is to give rigorous proofs of these conjectures and also extend these conjectures to generalizations of the first two models and a variant of the third model that include local rather than global interactions, i.e., instead of choosing the two interacting agents uniformly at random from the system, the agents are located on the vertex set of a general connected graph and can only interact with their neighbors.
Energy Technology Data Exchange (ETDEWEB)
Ahlroth, S.
2001-01-01
This licentiate thesis tries to bridge the gap between the theoretical and the practical studies in the field of environmental accounting. In the paper, 1 develop an optimal control theory model for adjusting NDP for the effects Of SO{sub 2} and NO{sub x} emissions, and subsequently insert empirically estimated values. The model includes correction entries for the effects on welfare, real capital, health and the quality and quantity of renewable natural resources. In the empirical valuation study, production losses were estimated with dose-response functions. Recreational and other welfare values were estimated by the contingent valuation (CV) method. Effects on capital depreciation are also included. For comparison, abatement costs and environmental protection expenditures for reducing sulfur and nitrogen emissions were estimated. The theoretical model was then utilized to calculate the adjustment to NDP in a consistent manner.
International Nuclear Information System (INIS)
Ahlroth, S.
2001-01-01
This licentiate thesis tries to bridge the gap between the theoretical and the practical studies in the field of environmental accounting. In the paper, 1 develop an optimal control theory model for adjusting NDP for the effects Of SO 2 and NO x emissions, and subsequently insert empirically estimated values. The model includes correction entries for the effects on welfare, real capital, health and the quality and quantity of renewable natural resources. In the empirical valuation study, production losses were estimated with dose-response functions. Recreational and other welfare values were estimated by the contingent valuation (CV) method. Effects on capital depreciation are also included. For comparison, abatement costs and environmental protection expenditures for reducing sulfur and nitrogen emissions were estimated. The theoretical model was then utilized to calculate the adjustment to NDP in a consistent manner
Rigorous force field optimization principles based on statistical distance minimization
Energy Technology Data Exchange (ETDEWEB)
Vlcek, Lukas, E-mail: vlcekl1@ornl.gov [Chemical Sciences Division, Geochemistry & Interfacial Sciences Group, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110 (United States); Joint Institute for Computational Sciences, University of Tennessee, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6173 (United States); Chialvo, Ariel A. [Chemical Sciences Division, Geochemistry & Interfacial Sciences Group, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110 (United States)
2015-10-14
We use the concept of statistical distance to define a measure of distinguishability between a pair of statistical mechanical systems, i.e., a model and its target, and show that its minimization leads to general convergence of the model’s static measurable properties to those of the target. We exploit this feature to define a rigorous basis for the development of accurate and robust effective molecular force fields that are inherently compatible with coarse-grained experimental data. The new model optimization principles and their efficient implementation are illustrated through selected examples, whose outcome demonstrates the higher robustness and predictive accuracy of the approach compared to other currently used methods, such as force matching and relative entropy minimization. We also discuss relations between the newly developed principles and established thermodynamic concepts, which include the Gibbs-Bogoliubov inequality and the thermodynamic length.
SDOF models for reinforced concrete beams under impulsive loads accounting for strain rate effects
Energy Technology Data Exchange (ETDEWEB)
Stochino, F., E-mail: fstochino@unica.it [Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Via Marengo 2, 09123 Cagliari (Italy); Carta, G., E-mail: giorgio_carta@unica.it [Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Via Marengo 2, 09123 Cagliari (Italy)
2014-09-15
Highlights: • Flexural failure of reinforced concrete beams under blast and impact loads is studied. • Two single degree of freedom models are formulated to predict the beam response. • Strain rate effects are taken into account for both models. • The theoretical response obtained from each model is compared with experimental data. • The two models give a good estimation of the maximum deflection at collapse. - Abstract: In this paper, reinforced concrete beams subjected to blast and impact loads are examined. Two single degree of freedom models are proposed to predict the response of the beam. The first model (denoted as “energy model”) is developed from the law of energy balance and assumes that the deformed shape of the beam is represented by its first vibration mode. In the second model (named “dynamic model”), the dynamic behavior of the beam is simulated by a spring-mass oscillator. In both formulations, the strain rate dependencies of the constitutive properties of the beams are considered by varying the parameters of the models at each time step of the computation according to the values of the strain rates of the materials (i.e. concrete and reinforcing steels). The efficiency of each model is evaluated by comparing the theoretical results with experimental data found in literature. The comparison shows that the energy model gives a good estimation of the maximum deflection of the beam at collapse, defined as the attainment of the ultimate strain in concrete. On the other hand, the dynamic model generally provides a smaller value of the maximum displacement. However, both approaches yield reliable results, even though they are based on some approximations. Being also very simple to implement, they may serve as an useful tool in practical applications.
International Nuclear Information System (INIS)
Rogers, J.D.
1994-01-01
This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport
Schweikardt, Thorsten; Olivares, Concepción; Solano, Francisco; Jaenicke, Elmar; García-Borrón, José Carlos; Decker, Heinz
2007-10-01
Tyrosinases are the first and rate-limiting enzymes in the synthesis of melanin pigments responsible for colouring hair, skin and eyes. Mutation of tyrosinases often decreases melanin production resulting in albinism, but the effects are not always understood at the molecular level. Homology modelling of mouse tyrosinase based on recently published crystal structures of non-mammalian tyrosinases provides an active site model accounting for loss-of-function mutations. According to the model, the copper-binding histidines are located in a helix bundle comprising four densely packed helices. A loop containing residues M374, S375 and V377 connects the CuA and CuB centres, with the peptide oxygens of M374 and V377 serving as hydrogen acceptors for the NH-groups of the imidazole rings of the copper-binding His367 and His180. Therefore, this loop is essential for the stability of the active site architecture. A double substitution (374)MS(375) --> (374)GG(375) or a single M374G mutation lead to a local perturbation of the protein matrix at the active site affecting the orientation of the H367 side chain, that may be unable to bind CuB reliably, resulting in loss of activity. The model also accounts for loss of function in two naturally occurring albino mutations, S380P and V393F. The hydroxyl group in S380 contributes to the correct orientation of M374, and the substitution of V393 for a bulkier phenylalanine sterically impedes correct side chain packing at the active site. Therefore, our model explains the mechanistic necessity for conservation of not only active site histidines but also adjacent amino acids in tyrosinase.
Directory of Open Access Journals (Sweden)
Czoli Christine
2011-10-01
Full Text Available Abstract Physician-researchers are bound by professional obligations stemming from both the role of the physician and the role of the researcher. Currently, the dominant models for understanding the relationship between physician-researchers' clinical duties and research duties fit into three categories: the similarity position, the difference position and the middle ground. The law may be said to offer a fourth "model" that is independent from these three categories. These models frame the expectations placed upon physician-researchers by colleagues, regulators, patients and research participants. This paper examines the extent to which the data from semi-structured interviews with 30 physician-researchers at three major pediatric hospitals in Canada reflect these traditional models. It seeks to determine the extent to which existing models align with the described lived experience of the pediatric physician-researchers interviewed. Ultimately, we find that although some physician-researchers make references to something like the weak version of the similarity position, the pediatric-researchers interviewed in this study did not describe their dual roles in a way that tightly mirrors any of the existing theoretical frameworks. We thus conclude that either physician-researchers are in need of better training regarding the nature of the accountability relationships that flow from their dual roles or that models setting out these roles and relationships must be altered to better reflect what we can reasonably expect of physician-researchers in a real-world environment.
Molenaar, Dylan; de Boeck, Paul
2018-06-01
In item response theory modeling of responses and response times, it is commonly assumed that the item responses have the same characteristics across the response times. However, heterogeneity might arise in the data if subjects resort to different response processes when solving the test items. These differences may be within-subject effects, that is, a subject might use a certain process on some of the items and a different process with different item characteristics on the other items. If the probability of using one process over the other process depends on the subject's response time, within-subject heterogeneity of the item characteristics across the response times arises. In this paper, the method of response mixture modeling is presented to account for such heterogeneity. Contrary to traditional mixture modeling where the full response vectors are classified, response mixture modeling involves classification of the individual elements in the response vector. In a simulation study, the response mixture model is shown to be viable in terms of parameter recovery. In addition, the response mixture model is applied to a real dataset to illustrate its use in investigating within-subject heterogeneity in the item characteristics across response times.
He, Shuangyan; Zhang, Xiaodong; Xiong, Yuanheng; Gray, Deric
2017-11-01
The subsurface remote sensing reflectance (rrs, sr-1), particularly its bidirectional reflectance distribution function (BRDF), depends fundamentally on the angular shape of the volume scattering functions (VSFs, m-1 sr-1). Recent technological advancement has greatly expanded the collection, and the knowledge of natural variability, of the VSFs of oceanic particles. This allows us to test the Zaneveld's theoretical rrs model that explicitly accounts for particle VSF shapes. We parameterized the rrs model based on HydroLight simulations using 114 VSFs measured in three coastal waters around the United States and in oceanic waters of North Atlantic Ocean. With the absorption coefficient (a), backscattering coefficient (bb), and VSF shape as inputs, the parameterized model is able to predict rrs with a root mean square relative error of ˜4% for solar zenith angles from 0 to 75°, viewing zenith angles from 0 to 60°, and viewing azimuth angles from 0 to 180°. A test with the field data indicates the performance of our model, when using only a and bb as inputs and selecting the VSF shape using bb, is comparable to or slightly better than the currently used models by Morel et al. and Lee et al. Explicitly expressing VSF shapes in rrs modeling has great potential to further constrain the uncertainty in the ocean color studies as our knowledge on the VSFs of natural particles continues to improve. Our study represents a first effort in this direction.
Nilsson, A.; Suttie, N.
2016-12-01
Sedimentary palaeomagnetic data may exhibit some degree of smoothing of the recorded field due to the gradual processes by which the magnetic signal is `locked-in' over time. Here we present a new Bayesian method to construct age-depth models based on palaeomagnetic data, taking into account and correcting for potential lock-in delay. The age-depth model is built on the widely used "Bacon" dating software by Blaauw and Christen (2011, Bayesian Analysis 6, 457-474) and is designed to combine both radiocarbon and palaeomagnetic measurements. To our knowledge, this is the first palaeomagnetic dating method that addresses the potential problems related post-depositional remanent magnetisation acquisition in age-depth modelling. Age-depth models, including site specific lock-in depth and lock-in filter function, produced with this method are shown to be consistent with independent results based on radiocarbon wiggle match dated sediment sections. Besides its primary use as a dating tool, our new method can also be used specifically to identify the most likely lock-in parameters for a specific record. We explore the potential to use these results to construct high-resolution geomagnetic field models based on sedimentary palaeomagnetic data, adjusting for smoothing induced by post-depositional remanent magnetisation acquisition. Potentially, this technique could enable reconstructions of Holocene geomagnetic field with the same amplitude of variability observed in archaeomagnetic field models for the past three millennia.
Toward a formalized account of attitudes: The Causal Attitude Network (CAN) model.
Dalege, Jonas; Borsboom, Denny; van Harreveld, Frenk; van den Berg, Helma; Conner, Mark; van der Maas, Han L J
2016-01-01
This article introduces the Causal Attitude Network (CAN) model, which conceptualizes attitudes as networks consisting of evaluative reactions and interactions between these reactions. Relevant evaluative reactions include beliefs, feelings, and behaviors toward the attitude object. Interactions between these reactions arise through direct causal influences (e.g., the belief that snakes are dangerous causes fear of snakes) and mechanisms that support evaluative consistency between related contents of evaluative reactions (e.g., people tend to align their belief that snakes are useful with their belief that snakes help maintain ecological balance). In the CAN model, the structure of attitude networks conforms to a small-world structure: evaluative reactions that are similar to each other form tight clusters, which are connected by a sparser set of "shortcuts" between them. We argue that the CAN model provides a realistic formalized measurement model of attitudes and therefore fills a crucial gap in the attitude literature. Furthermore, the CAN model provides testable predictions for the structure of attitudes and how they develop, remain stable, and change over time. Attitude strength is conceptualized in terms of the connectivity of attitude networks and we show that this provides a parsimonious account of the differences between strong and weak attitudes. We discuss the CAN model in relation to possible extensions, implication for the assessment of attitudes, and possibilities for further study. (c) 2015 APA, all rights reserved).
Accounting for sex differences in PTSD: A multi-variable mediation model.
Christiansen, Dorte M; Hansen, Maj
2015-01-01
Approximately twice as many females as males are diagnosed with posttraumatic stress disorder (PTSD). However, little is known about why females report more PTSD symptoms than males. Prior studies have generally focused on few potential mediators at a time and have often used methods that were not ideally suited to test for mediation effects. Prior research has identified a number of individual risk factors that may contribute to sex differences in PTSD severity, although these cannot fully account for the increased symptom levels in females when examined individually. The present study is the first to systematically test the hypothesis that a combination of pre-, peri-, and posttraumatic risk factors more prevalent in females can account for sex differences in PTSD severity. The study was a quasi-prospective questionnaire survey assessing PTSD and related variables in 73.3% of all Danish bank employees exposed to bank robbery during the period from April 2010 to April 2011. Participants filled out questionnaires 1 week (T1, N=450) and 6 months after the robbery (T2, N=368; 61.1% females). Mediation was examined using an analysis designed specifically to test a multiple mediator model. Females reported more PTSD symptoms than males and higher levels of neuroticism, depression, physical anxiety sensitivity, peritraumatic fear, horror, and helplessness (the A2 criterion), tonic immobility, panic, dissociation, negative posttraumatic cognitions about self and the world, and feeling let down. These variables were included in the model as potential mediators. The combination of risk factors significantly mediated the association between sex and PTSD severity, accounting for 83% of the association. The findings suggest that females report more PTSD symptoms because they experience higher levels of associated risk factors. The results are relevant to other trauma populations and to other trauma-related psychiatric disorders more prevalent in females, such as depression
Accounting for sex differences in PTSD: A multi-variable mediation model
Directory of Open Access Journals (Sweden)
Dorte M. Christiansen
2015-01-01
Full Text Available Background: Approximately twice as many females as males are diagnosed with posttraumatic stress disorder (PTSD. However, little is known about why females report more PTSD symptoms than males. Prior studies have generally focused on few potential mediators at a time and have often used methods that were not ideally suited to test for mediation effects. Prior research has identified a number of individual risk factors that may contribute to sex differences in PTSD severity, although these cannot fully account for the increased symptom levels in females when examined individually. Objective: The present study is the first to systematically test the hypothesis that a combination of pre-, peri-, and posttraumatic risk factors more prevalent in females can account for sex differences in PTSD severity. Method: The study was a quasi-prospective questionnaire survey assessing PTSD and related variables in 73.3% of all Danish bank employees exposed to bank robbery during the period from April 2010 to April 2011. Participants filled out questionnaires 1 week (T1, N=450 and 6 months after the robbery (T2, N=368; 61.1% females. Mediation was examined using an analysis designed specifically to test a multiple mediator model. Results: Females reported more PTSD symptoms than males and higher levels of neuroticism, depression, physical anxiety sensitivity, peritraumatic fear, horror, and helplessness (the A2 criterion, tonic immobility, panic, dissociation, negative posttraumatic cognitions about self and the world, and feeling let down. These variables were included in the model as potential mediators. The combination of risk factors significantly mediated the association between sex and PTSD severity, accounting for 83% of the association. Conclusions: The findings suggest that females report more PTSD symptoms because they experience higher levels of associated risk factors. The results are relevant to other trauma populations and to other trauma
Rigor or mortis: best practices for preclinical research in neuroscience.
Steward, Oswald; Balice-Gordon, Rita
2014-11-05
Numerous recent reports document a lack of reproducibility of preclinical studies, raising concerns about potential lack of rigor. Examples of lack of rigor have been extensively documented and proposals for practices to improve rigor are appearing. Here, we discuss some of the details and implications of previously proposed best practices and consider some new ones, focusing on preclinical studies relevant to human neurological and psychiatric disorders. Copyright © 2014 Elsevier Inc. All rights reserved.
[Experimental study of restiffening of the rigor mortis].
Wang, X; Li, M; Liao, Z G; Yi, X F; Peng, X M
2001-11-01
To observe changes of the length of sarcomere of rat when restiffening. We measured the length of sarcomere of quadriceps in 40 rats in different condition by scanning electron microscope. The length of sarcomere of rigor mortis without destroy is obviously shorter than that of restiffening. The length of sarcomere is negatively correlative to the intensity of rigor mortis. Measuring the length of sarcomere can determine the intensity of rigor mortis and provide evidence for estimation of time since death.
Helle, Samuli
2018-03-01
Revealing causal effects from correlative data is very challenging and a contemporary problem in human life history research owing to the lack of experimental approach. Problems with causal inference arising from measurement error in independent variables, whether related either to inaccurate measurement technique or validity of measurements, seem not well-known in this field. The aim of this study is to show how structural equation modeling (SEM) with latent variables can be applied to account for measurement error in independent variables when the researcher has recorded several indicators of a hypothesized latent construct. As a simple example of this approach, measurement error in lifetime allocation of resources to reproduction in Finnish preindustrial women is modelled in the context of the survival cost of reproduction. In humans, lifetime energetic resources allocated in reproduction are almost impossible to quantify with precision and, thus, typically used measures of lifetime reproductive effort (e.g., lifetime reproductive success and parity) are likely to be plagued by measurement error. These results are contrasted with those obtained from a traditional regression approach where the single best proxy of lifetime reproductive effort available in the data is used for inference. As expected, the inability to account for measurement error in women's lifetime reproductive effort resulted in the underestimation of its underlying effect size on post-reproductive survival. This article emphasizes the advantages that the SEM framework can provide in handling measurement error via multiple-indicator latent variables in human life history studies. © 2017 Wiley Periodicals, Inc.
Rozanov, V. V.; Dinter, T.; Rozanov, A. V.; Wolanin, A.; Bracher, A.; Burrows, J. P.
2017-06-01
SCIATRAN is a comprehensive software package which is designed to model radiative transfer processes in the terrestrial atmosphere and ocean in the spectral range from the ultraviolet to the thermal infrared (0.18-40 μm). It accounts for multiple scattering processes, polarization, thermal emission and ocean-atmosphere coupling. The main goal of this paper is to present a recently developed version of SCIATRAN which takes into account accurately inelastic radiative processes in both the atmosphere and the ocean. In the scalar version of the coupled ocean-atmosphere radiative transfer solver presented by Rozanov et al. [61] we have implemented the simulation of the rotational Raman scattering, vibrational Raman scattering, chlorophyll and colored dissolved organic matter fluorescence. In this paper we discuss and explain the numerical methods used in SCIATRAN to solve the scalar radiative transfer equation including trans-spectral processes, and demonstrate how some selected radiative transfer problems are solved using the SCIATRAN package. In addition we present selected comparisons of SCIATRAN simulations with those published benchmark results, independent radiative transfer models, and various measurements from satellite, ground-based, and ship-borne instruments. The extended SCIATRAN software package along with a detailed User's Guide is made available for scientists and students, who are undertaking their own research typically at universities, via the web page of the Institute of Environmental Physics (IUP), University of Bremen: http://www.iup.physik.uni-bremen.de.
Implementation of a cost-accounting model in a biobank: practical implications.
Gonzalez-Sanchez, Maria Beatriz; Lopez-Valeiras, Ernesto; García-Montero, Andres C
2014-01-01
Given the state of global economy, cost measurement and control have become increasingly relevant over the past years. The scarcity of resources and the need to use these resources more efficiently is making cost information essential in management, even in non-profit public institutions. Biobanks are no exception. However, no empirical experiences on the implementation of cost accounting in biobanks have been published to date. The aim of this paper is to present a step-by-step implementation of a cost-accounting tool for the main production and distribution activities of a real/active biobank, including a comprehensive explanation on how to perform the calculations carried out in this model. Two mathematical models for the analysis of (1) production costs and (2) request costs (order management and sample distribution) have stemmed from the analysis of the results of this implementation, and different theoretical scenarios have been prepared. Global analysis and discussion provides valuable information for internal biobank management and even for strategic decisions at the research and development governmental policies level.
A Modified Model to Estimate Building Rental Multipiers Accounting for Advalorem Operating Expenses
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Smolyak S.A.
2016-09-01
Full Text Available To develop ideas on building element valuation contained in the first article on the subject published in REMV, we propose an elaboration of the approach accounting for ad valorem expenses incidental to property management, such as land taxes, income/capital gains tax, and insurance premium costs; all such costs, being of an ad valorem nature in the first instance, cause circularity in the logic of the model, which, however, is not intractable under the proposed approach. The resulting formulas for carrying out practical estimation of building rental multipliers and, in consequence, of building values, turn out to be somewhat modified, and we demonstrate the sensitivity of the developed approach to the impact of these ad valorem factors. On the other hand, it is demonstrated that (accounting for building depreciation charges, which should seemingly be included among the considered ad valorem factors, cancel out and do not have any impact on the resulting estimates. However, treating the depreciation of buildings in quantifiable economic terms as a reduction in derivable operating benefits over time (instead of mere physical indications, such as age, we also demonstrate that the approach has implications for estimating the economic service lives of buildings and can be practical when used in conjunction with the market-related approach to valuation – from which the requisite model inputs can be extracted as shown in the final part of the paper.
Standardized facility record and report model system (FARMS) for material accounting and control
International Nuclear Information System (INIS)
Nishimura, Hideo; Ihara, Hitoshi; Hisamatsu, Yoshinori.
1990-07-01
A facility in which nuclear materials are handled maintains a facility system of accounting for and control of nuclear material. Such a system contains, as one of key elements, a record and report system. This record and report information system is a rather complex one because it needs to conform to various requirements from the national or international safeguards authorities and from the plant operator who has to achieve a safe and economical operation of the plant. Therefore it is mandatory to computerize such information system. The authors have reviewed these requirements and standardized the book-keeping and reporting procedures in line with their computerization. On the basis of this result the authors have developed a computer system, FARMS, named as an acronym of standardized facility record and report model system, mainly reflecting the requirements from the national and international safeguards authorities. The development of FARMS has also been carried out as a JASPAS - Japan Support Programme for Agency Safeguards - project since 1985 and the FARMS code was demonstrated as an accountancy tool in the regional SSAC training courses held in Japan in 1985 and 1987. This report describes the standardization of a record and report system at the facility level, its computerization as a model system and the demonstration of the developed system, FARMS. (author)
Directory of Open Access Journals (Sweden)
Igor KOLESNIKOV
2016-12-01
Full Text Available Serviceability of metal-polymeric "dry-friction" sliding bearings depends on many parameters, including the rotational speed, friction coefficient, thermal and mechanical properties of the bearing system and, as a result, the value of contact temperature. The objective of this study is to develop a computational model for the metallic-polymer bearing, determination on the basis of this model temperature distribution, equivalent and contact stresses for elements of the bearing arrangement and selection of the optimal parameters for the bearing system to achieve thermal balance. Static problem for the combined sliding bearing with the account of heat generation due to friction has been studied in [1]; the dynamic thermoelastic problem of the shaft rotation in a single and double layer bronze bearings were investigated in [2, 3].
Dosimetric effects of edema in permanent prostate seed implants: a rigorous solution
International Nuclear Information System (INIS)
Chen Zhe; Yue Ning; Wang Xiaohong; Roberts, Kenneth B.; Peschel, Richard; Nath, Ravinder
2000-01-01
Purpose: To derive a rigorous analytic solution to the dosimetric effects of prostate edema so that its impact on the conventional pre-implant and post-implant dosimetry can be studied for any given radioactive isotope and edema characteristics. Methods and Materials: The edema characteristics observed by Waterman et al (Int. J. Rad. Onc. Biol. Phys, 41:1069-1077; 1998) was used to model the time evolution of the prostate and the seed locations. The total dose to any part of prostate tissue from a seed implant was calculated analytically by parameterizing the dose fall-off from a radioactive seed as a single inverse power function of distance, with proper account of the edema-induced time evolution. The dosimetric impact of prostate edema was determined by comparing the dose calculated with full consideration of prostate edema to that calculated with the conventional dosimetry approach where the seed locations and the target volume are assumed to be stationary. Results: A rigorous analytic solution on the relative dosimetric effects of prostate edema was obtained. This solution proved explicitly that the relative dosimetric effects of edema, as found in the previous numerical studies by Yue et. al. (Int. J. Radiat. Oncol. Biol. Phys. 43, 447-454, 1999), are independent of the size and the shape of the implant target volume and are independent of the number and the locations of the seeds implanted. It also showed that the magnitude of relative dosimetric effects is independent of the location of dose evaluation point within the edematous target volume. It implies that the relative dosimetric effects of prostate edema are universal with respect to a given isotope and edema characteristic. A set of master tables for the relative dosimetric effects of edema were obtained for a wide range of edema characteristics for both 125 I and 103 Pd prostate seed implants. Conclusions: A rigorous analytic solution of the relative dosimetric effects of prostate edema has been
Calibration of an experimental model of tritium storage bed designed for 'in situ' accountability
International Nuclear Information System (INIS)
Bidica, Nicolae; Stefanescu, Ioan; Bucur, Ciprian; Bulubasa, Gheorghe; Deaconu, Mariea
2009-01-01
Full text: Objectives: Tritium accountancy of the storage beds in tritium facilities is an important issue for tritium inventory control. The purpose of our work was to perform calibration of an experimental model of tritium storage bed with a special design, using electric heaters to simulate tritium decay, and to evaluate the detection limit of the accountancy method. The objective of this paper is to present an experimental method used for calibration of the storage bed and the experimental results consisting of calibration curves and detection limit. Our method is based on a 'self-assaying' tritium storage bed. The basic characteristics of the design of our storage bed consists, in principle, of a uniform distribution of the storage material on several copper thin fins (in order to obtain a uniform temperature field inside the bed), an electrical heat source to simulate the tritium decay heat, a system of thermocouples for measuring the temperature field inside the bed, and good thermal isolation of the bed from the external environment. Within this design of the tritium storage bed, the tritium accounting method is based on determining the decay heat of tritium by measuring the temperature increase of the isolated storage bed. Experimental procedure consisted in measuring of temperature field inside the bed for few values of the power injected with the aid of electrical heat source. Data have been collected for few hours and the temperature increase rate was determined for each value of the power injected. Graphical representation of temperature rise versus injected powers was obtained. This accounting method of tritium inventory stored as metal tritide is a reliable solution for in-situ tritium accountability in a tritium handling facility. Several improvements can be done regarding the design of the storage bed in order to improve the measurement accuracy and to obtain a lower detection limit as for instance use of more accurate thermocouples or special
Directory of Open Access Journals (Sweden)
ORHAN ELMACI
2014-06-01
Full Text Available The present study intended to investigate the “Balance Scorecard (BSC model integrated with Resource Consumption Accounting (RCA” which helps to evaluate the enterprise as matrix structure in its all parts. It aims to measure how much tangible and intangible values (assets of enterprises contribute to the enterprises. In other words, it measures how effectively, actively, and efficiently these values (assets are used. In short, it aims to measure sustainable competency of enterprises. As expressing the effect of tangible and intangible values (assets of the enterprise on the performance in mathematical and statistical methods is insufficient, it is targeted that RCA Method integrated with BSC model is based on matrix structure and control models. The effects of all complex factors in the enterprise on the performance (productivity and efficiency estimated algorithmically with cause and effect diagram. The contributions of matrix structures for reaching the management functional targets of the enterprises that operate in market competitive environment increasing day to day, is discussed. So in the context of modern management theories, as a contribution to BSC approach which is in the foreground in today’s administrative science of enterprises in matrix organizational structures, multidimensional performance evaluation model -RCA integrated with BSC Model proposal- is presented as strategic planning and strategic evaluation instrument.
A one-dimensional Q-machine model taking into account charge-exchange collisions
International Nuclear Information System (INIS)
Maier, H.; Kuhn, S.
1992-01-01
The Q-machine is a nontrivial bounded plasma system which is excellently suited not only for fundamental plasma physics investigations but also for the development and testing of new theoretical methods for modeling such systems. However, although Q-machines have now been around for over thirty years, it appears that there exist no comprehensive theoretical models taking into account their considerable geometrical and physical complexity with a reasonable degree of self-consistency. In the present context we are concerned with the low-density, single-emitter Q-machine, for which the most widely used model is probably the (one-dimensional) ''collisionless plane-diode model'', which has originally been developed for thermionic diodes. Although the validity of this model is restricted to certain ''axial'' phenomena, we consider it a suitable starting point for extensions of various kinds. While a generalization to two-dimensional geometry (with still collisionless plasma) is being reported elsewhere, the present work represents a first extension to collisional plasma (with still one-dimensional geometry). (author) 12 refs., 2 figs
Gaussian covariance graph models accounting for correlated marker effects in genome-wide prediction.
Martínez, C A; Khare, K; Rahman, S; Elzo, M A
2017-10-01
Several statistical models used in genome-wide prediction assume uncorrelated marker allele substitution effects, but it is known that these effects may be correlated. In statistics, graphical models have been identified as a useful tool for covariance estimation in high-dimensional problems and it is an area that has recently experienced a great expansion. In Gaussian covariance graph models (GCovGM), the joint distribution of a set of random variables is assumed to be Gaussian and the pattern of zeros of the covariance matrix is encoded in terms of an undirected graph G. In this study, methods adapting the theory of GCovGM to genome-wide prediction were developed (Bayes GCov, Bayes GCov-KR and Bayes GCov-H). In simulated data sets, improvements in correlation between phenotypes and predicted breeding values and accuracies of predicted breeding values were found. Our models account for correlation of marker effects and permit to accommodate general structures as opposed to models proposed in previous studies, which consider spatial correlation only. In addition, they allow incorporation of biological information in the prediction process through its use when constructing graph G, and their extension to the multi-allelic loci case is straightforward. © 2017 Blackwell Verlag GmbH.
A Model for Urban Environment and Resource Planning Based on Green GDP Accounting System
Directory of Open Access Journals (Sweden)
Linyu Xu
2013-01-01
Full Text Available The urban environment and resources are currently on course that is unsustainable in the long run due to excessive human pursuit of economic goals. Thus, it is very important to develop a model to analyse the relationship between urban economic development and environmental resource protection during the process of rapid urbanisation. This paper proposed a model to identify the key factors in urban environment and resource regulation based on a green GDP accounting system, which consisted of four parts: economy, society, resource, and environment. In this model, the analytic hierarchy process (AHP method and a modified Pearl curve model were combined to allow for dynamic evaluation, with higher green GDP value as the planning target. The model was applied to the environmental and resource planning problem of Wuyishan City, and the results showed that energy use was a key factor that influenced the urban environment and resource development. Biodiversity and air quality were the most sensitive factors that influenced the value of green GDP in the city. According to the analysis, the urban environment and resource planning could be improved for promoting sustainable development in Wuyishan City.
Student’s rigorous mathematical thinking based on cognitive style
Fitriyani, H.; Khasanah, U.
2017-12-01
The purpose of this research was to determine the rigorous mathematical thinking (RMT) of mathematics education students in solving math problems in terms of reflective and impulsive cognitive styles. The research used descriptive qualitative approach. Subjects in this research were 4 students of the reflective and impulsive cognitive style which was each consisting male and female subjects. Data collection techniques used problem-solving test and interview. Analysis of research data used Miles and Huberman model that was reduction of data, presentation of data, and conclusion. The results showed that impulsive male subjects used three levels of the cognitive function required for RMT that were qualitative thinking, quantitative thinking with precision, and relational thinking completely while the other three subjects were only able to use cognitive function at qualitative thinking level of RMT. Therefore the subject of impulsive male has a better RMT ability than the other three research subjects.
Rigorous Quantum Field Theory A Festschrift for Jacques Bros
Monvel, Anne Boutet; Iagolnitzer, Daniel; Moschella, Ugo
2007-01-01
Jacques Bros has greatly advanced our present understanding of rigorous quantum field theory through numerous fundamental contributions. This book arose from an international symposium held in honour of Jacques Bros on the occasion of his 70th birthday, at the Department of Theoretical Physics of the CEA in Saclay, France. The impact of the work of Jacques Bros is evident in several articles in this book. Quantum fields are regarded as genuine mathematical objects, whose various properties and relevant physical interpretations must be studied in a well-defined mathematical framework. The key topics in this volume include analytic structures of Quantum Field Theory (QFT), renormalization group methods, gauge QFT, stability properties and extension of the axiomatic framework, QFT on models of curved spacetimes, QFT on noncommutative Minkowski spacetime. Contributors: D. Bahns, M. Bertola, R. Brunetti, D. Buchholz, A. Connes, F. Corbetta, S. Doplicher, M. Dubois-Violette, M. Dütsch, H. Epstein, C.J. Fewster, K....
An agent-based simulation model to study accountable care organizations.
Liu, Pai; Wu, Shinyi
2016-03-01
Creating accountable care organizations (ACOs) has been widely discussed as a strategy to control rapidly rising healthcare costs and improve quality of care; however, building an effective ACO is a complex process involving multiple stakeholders (payers, providers, patients) with their own interests. Also, implementation of an ACO is costly in terms of time and money. Immature design could cause safety hazards. Therefore, there is a need for analytical model-based decision-support tools that can predict the outcomes of different strategies to facilitate ACO design and implementation. In this study, an agent-based simulation model was developed to study ACOs that considers payers, healthcare providers, and patients as agents under the shared saving payment model of care for congestive heart failure (CHF), one of the most expensive causes of sometimes preventable hospitalizations. The agent-based simulation model has identified the critical determinants for the payment model design that can motivate provider behavior changes to achieve maximum financial and quality outcomes of an ACO. The results show nonlinear provider behavior change patterns corresponding to changes in payment model designs. The outcomes vary by providers with different quality or financial priorities, and are most sensitive to the cost-effectiveness of CHF interventions that an ACO implements. This study demonstrates an increasingly important method to construct a healthcare system analytics model that can help inform health policy and healthcare management decisions. The study also points out that the likely success of an ACO is interdependent with payment model design, provider characteristics, and cost and effectiveness of healthcare interventions.
Air quality modeling for accountability research: Operational, dynamic, and diagnostic evaluation
Henneman, Lucas R. F.; Liu, Cong; Hu, Yongtao; Mulholland, James A.; Russell, Armistead G.
2017-10-01
Photochemical grid models play a central role in air quality regulatory frameworks, including in air pollution accountability research, which seeks to demonstrate the extent to which regulations causally impacted emissions, air quality, and public health. There is a need, however, to develop and demonstrate appropriate practices for model application and evaluation in an accountability framework. We employ a combination of traditional and novel evaluation techniques to assess four years (2001-02, 2011-12) of simulated pollutant concentrations across a decade of major emissions reductions using the Community Multiscale Air Quality (CMAQ) model. We have grouped our assessments in three categories: Operational evaluation investigates how well CMAQ captures absolute concentrations; dynamic evaluation investigates how well CMAQ captures changes in concentrations across the decade of changing emissions; diagnostic evaluation investigates how CMAQ attributes variability in concentrations and sensitivities to emissions between meteorology and emissions, and how well this attribution compares to empirical statistical models. In this application, CMAQ captures O3 and PM2.5 concentrations and change over the decade in the Eastern United States similarly to past CMAQ applications and in line with model evaluation guidance; however, some PM2.5 species-EC, OC, and sulfate in particular-exhibit high biases in various months. CMAQ-simulated PM2.5 has a high bias in winter months and low bias in the summer, mainly due to a high bias in OC during the cold months and low bias in OC and sulfate during the summer. Simulated O3 and PM2.5 changes across the decade have normalized mean bias of less than 2.5% and 17%, respectively. Detailed comparisons suggest biased EC emissions, negative wintertime SO42- sensitivities to mobile source emissions, and incomplete capture of OC chemistry in the summer and winter. Photochemical grid model-simulated O3 and PM2.5 responses to emissions and
A margin model to account for respiration-induced tumour motion and its variability
International Nuclear Information System (INIS)
Coolens, Catherine; Webb, Steve; Evans, Phil M; Shirato, H; Nishioka, K
2008-01-01
In order to reduce the sensitivity of radiotherapy treatments to organ motion, compensation methods are being investigated such as gating of treatment delivery, tracking of tumour position, 4D scanning and planning of the treatment, etc. An outstanding problem that would occur with all these methods is the assumption that breathing motion is reproducible throughout the planning and delivery process of treatment. This is obviously not a realistic assumption and is one that will introduce errors. A dynamic internal margin model (DIM) is presented that is designed to follow the tumour trajectory and account for the variability in respiratory motion. The model statistically describes the variation of the breathing cycle over time, i.e. the uncertainty in motion amplitude and phase reproducibility, in a polar coordinate system from which margins can be derived. This allows accounting for an additional gating window parameter for gated treatment delivery as well as minimizing the area of normal tissue irradiated. The model was illustrated with abdominal motion for a patient with liver cancer and tested with internal 3D lung tumour trajectories. The results confirm that the respiratory phases around exhale are most reproducible and have the smallest variation in motion amplitude and phase (approximately 2 mm). More importantly, the margin area covering normal tissue is significantly reduced by using trajectory-specific margins (as opposed to conventional margins) as the angular component is by far the largest contributor to the margin area. The statistical approach to margin calculation, in addition, offers the possibility for advanced online verification and updating of breathing variation as more data become available
International Nuclear Information System (INIS)
Rozanov, V.V.; Dinter, T.; Rozanov, A.V.; Wolanin, A.; Bracher, A.; Burrows, J.P.
2017-01-01
SCIATRAN is a comprehensive software package which is designed to model radiative transfer processes in the terrestrial atmosphere and ocean in the spectral range from the ultraviolet to the thermal infrared (0.18–40 μm). It accounts for multiple scattering processes, polarization, thermal emission and ocean–atmosphere coupling. The main goal of this paper is to present a recently developed version of SCIATRAN which takes into account accurately inelastic radiative processes in both the atmosphere and the ocean. In the scalar version of the coupled ocean–atmosphere radiative transfer solver presented by Rozanov et al. we have implemented the simulation of the rotational Raman scattering, vibrational Raman scattering, chlorophyll and colored dissolved organic matter fluorescence. In this paper we discuss and explain the numerical methods used in SCIATRAN to solve the scalar radiative transfer equation including trans-spectral processes, and demonstrate how some selected radiative transfer problems are solved using the SCIATRAN package. In addition we present selected comparisons of SCIATRAN simulations with those published benchmark results, independent radiative transfer models, and various measurements from satellite, ground-based, and ship-borne instruments. The extended SCIATRAN software package along with a detailed User's Guide is made available for scientists and students, who are undertaking their own research typically at universities, via the web page of the Institute of Environmental Physics (IUP), University of Bremen: (http://www.iup.physik.uni-bremen.de). - Highlights: • A new version of the software package SCIATRAN is presented. • Inelastic scattering in water and atmosphere is implemented in SCIATRAN. • Raman scattering and fluorescence can be included in radiative transfer calculations. • Comparisons to other radiative transfer models show excellent agreement. • Comparisons to observations show consistent results.
Adjusting particle-size distributions to account for aggregation in tephra-deposit model forecasts
Mastin, Larry G.; Van Eaton, Alexa; Durant, A.J.
2016-01-01
Volcanic ash transport and dispersion (VATD) models are used to forecast tephra deposition during volcanic eruptions. Model accuracy is limited by the fact that fine-ash aggregates (clumps into clusters), thus altering patterns of deposition. In most models this is accounted for by ad hoc changes to model input, representing fine ash as aggregates with density ρagg, and a log-normal size distribution with median μagg and standard deviation σagg. Optimal values may vary between eruptions. To test the variance, we used the Ash3d tephra model to simulate four deposits: 18 May 1980 Mount St. Helens; 16–17 September 1992 Crater Peak (Mount Spurr); 17 June 1996 Ruapehu; and 23 March 2009 Mount Redoubt. In 192 simulations, we systematically varied μagg and σagg, holding ρagg constant at 600 kg m−3. We evaluated the fit using three indices that compare modeled versus measured (1) mass load at sample locations; (2) mass load versus distance along the dispersal axis; and (3) isomass area. For all deposits, under these inputs, the best-fit value of μagg ranged narrowly between ∼ 2.3 and 2.7φ (0.20–0.15 mm), despite large variations in erupted mass (0.25–50 Tg), plume height (8.5–25 km), mass fraction of fine ( discrete process that is insensitive to eruptive style or magnitude. This result offers the potential for a simple, computationally efficient parameterization scheme for use in operational model forecasts. Further research may indicate whether this narrow range also reflects physical constraints on processes in the evolving cloud.
Modelling of gas-metal arc welding taking into account metal vapour
Energy Technology Data Exchange (ETDEWEB)
Schnick, M; Fuessel, U; Hertel, M; Haessler, M [Institute of Surface and Manufacturing Technology, Technische Universitaet Dresden, D-01062 Dresden (Germany); Spille-Kohoff, A [CFX Berlin Software GmbH, Karl-Marx-Allee 90, 10243 Berlin (Germany); Murphy, A B [CSIRO Materials Science and Engineering, PO Box 218, Lindfield NSW 2070 (Australia)
2010-11-03
The most advanced numerical models of gas-metal arc welding (GMAW) neglect vaporization of metal, and assume an argon atmosphere for the arc region, as is also common practice for models of gas-tungsten arc welding (GTAW). These models predict temperatures above 20 000 K and a temperature distribution similar to GTAW arcs. However, spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to measurements of GTAW arcs, they have shown the presence of a central local minimum of the radial temperature distribution. This paper presents a GMAW model that takes into account metal vapour and that is able to predict the local central minimum in the radial distributions of temperature and electric current density. The influence of different values for the net radiative emission coefficient of iron vapour, which vary by up to a factor of hundred, is examined. It is shown that these net emission coefficients cause differences in the magnitudes, but not in the overall trends, of the radial distribution of temperature and current density. Further, the influence of the metal vaporization rate is investigated. We present evidence that, for higher vaporization rates, the central flow velocity inside the arc is decreased and can even change direction so that it is directed from the workpiece towards the wire, although the outer plasma flow is still directed towards the workpiece. In support of this thesis, we have attempted to reproduce the measurements of Zielinska et al for spray-transfer mode GMAW numerically, and have obtained reasonable agreement.
Kamarianakis, Yiannis; Gao, H Oliver
2010-02-15
Collecting and analyzing high frequency emission measurements has become very usual during the past decade as significantly more information with respect to formation conditions can be collected than from regulated bag measurements. A challenging issue for researchers is the accurate time-alignment between tailpipe measurements and engine operating variables. An alignment procedure should take into account both the reaction time of the analyzers and the dynamics of gas transport in the exhaust and measurement systems. This paper discusses a statistical modeling framework that compensates for variable exhaust transport delay while relating tailpipe measurements with engine operating covariates. Specifically it is shown that some variants of the smooth transition regression model allow for transport delays that vary smoothly as functions of the exhaust flow rate. These functions are characterized by a pair of coefficients that can be estimated via a least-squares procedure. The proposed models can be adapted to encompass inherent nonlinearities that were implicit in previous instantaneous emissions modeling efforts. This article describes the methodology and presents an illustrative application which uses data collected from a diesel bus under real-world driving conditions.
Material Protection, Accounting, and Control Technologies (MPACT): Modeling and Simulation Roadmap
Energy Technology Data Exchange (ETDEWEB)
Cipiti, Benjamin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dunn, Timothy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Durbin, Samual [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Durkee, Joe W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); England, Jeff [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jones, Robert [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Ketusky, Edward [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Li, Shelly [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lindgren, Eric [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Meier, David [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Miller, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Osburn, Laura Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pereira, Candido [Argonne National Lab. (ANL), Argonne, IL (United States); Rauch, Eric Benton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Scaglione, John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Scherer, Carolynn P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sprinkle, James K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Yoo, Tae-Sic [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2016-08-05
The development of sustainable advanced nuclear fuel cycles is a long-term goal of the Office of Nuclear Energy’s (DOE-NE) Fuel Cycle Technologies program. The Material Protection, Accounting, and Control Technologies (MPACT) campaign is supporting research and development (R&D) of advanced instrumentation, analysis tools, and integration methodologies to meet this goal. This advanced R&D is intended to facilitate safeguards and security by design of fuel cycle facilities. The lab-scale demonstration of a virtual facility, distributed test bed, that connects the individual tools being developed at National Laboratories and university research establishments, is a key program milestone for 2020. These tools will consist of instrumentation and devices as well as computer software for modeling. To aid in framing its long-term goal, during FY16, a modeling and simulation roadmap is being developed for three major areas of investigation: (1) radiation transport and sensors, (2) process and chemical models, and (3) shock physics and assessments. For each area, current modeling approaches are described, and gaps and needs are identified.
Integrated Approach Model of Risk, Control and Auditing of Accounting Information Systems
Directory of Open Access Journals (Sweden)
Claudiu BRANDAS
2013-01-01
Full Text Available The use of IT in the financial and accounting processes is growing fast and this leads to an increase in the research and professional concerns about the risks, control and audit of Ac-counting Information Systems (AIS. In this context, the risk and control of AIS approach is a central component of processes for IT audit, financial audit and IT Governance. Recent studies in the literature on the concepts of risk, control and auditing of AIS outline two approaches: (1 a professional approach in which we can fit ISA, COBIT, IT Risk, COSO and SOX, and (2 a research oriented approach in which we emphasize research on continuous auditing and fraud using information technology. Starting from the limits of existing approaches, our study is aimed to developing and testing an Integrated Approach Model of Risk, Control and Auditing of AIS on three cycles of business processes: purchases cycle, sales cycle and cash cycle in order to improve the efficiency of IT Governance, as well as ensuring integrity, reality, accuracy and availability of financial statements.
Raza, Hendra; Maksum, Azhar; Erlina; Lumban Raja, Prihatin
2014-01-01
Azhar Maksum This study aims to examine empirically the antecedents of individual performance on its consequences of turnover intention in public accounting firms. There are eight variables measured which consists of auditors' empowerment, innovation professionalism, role ambiguity, role conflict, organizational commitment, individual performance and turnover intention. Data analysis is based on 163 public accountant using the Structural Equation Modeling assisted with an appli...
Accounting for treatment use when validating a prognostic model: a simulation study.
Pajouheshnia, Romin; Peelen, Linda M; Moons, Karel G M; Reitsma, Johannes B; Groenwold, Rolf H H
2017-07-14
Prognostic models often show poor performance when applied to independent validation data sets. We illustrate how treatment use in a validation set can affect measures of model performance and present the uses and limitations of available analytical methods to account for this using simulated data. We outline how the use of risk-lowering treatments in a validation set can lead to an apparent overestimation of risk by a prognostic model that was developed in a treatment-naïve cohort to make predictions of risk without treatment. Potential methods to correct for the effects of treatment use when testing or validating a prognostic model are discussed from a theoretical perspective.. Subsequently, we assess, in simulated data sets, the impact of excluding treated individuals and the use of inverse probability weighting (IPW) on the estimated model discrimination (c-index) and calibration (observed:expected ratio and calibration plots) in scenarios with different patterns and effects of treatment use. Ignoring the use of effective treatments in a validation data set leads to poorer model discrimination and calibration than would be observed in the untreated target population for the model. Excluding treated individuals provided correct estimates of model performance only when treatment was randomly allocated, although this reduced the precision of the estimates. IPW followed by exclusion of the treated individuals provided correct estimates of model performance in data sets where treatment use was either random or moderately associated with an individual's risk when the assumptions of IPW were met, but yielded incorrect estimates in the presence of non-positivity or an unobserved confounder. When validating a prognostic model developed to make predictions of risk without treatment, treatment use in the validation set can bias estimates of the performance of the model in future targeted individuals, and should not be ignored. When treatment use is random, treated
Accounting for treatment use when validating a prognostic model: a simulation study
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Romin Pajouheshnia
2017-07-01
Full Text Available Abstract Background Prognostic models often show poor performance when applied to independent validation data sets. We illustrate how treatment use in a validation set can affect measures of model performance and present the uses and limitations of available analytical methods to account for this using simulated data. Methods We outline how the use of risk-lowering treatments in a validation set can lead to an apparent overestimation of risk by a prognostic model that was developed in a treatment-naïve cohort to make predictions of risk without treatment. Potential methods to correct for the effects of treatment use when testing or validating a prognostic model are discussed from a theoretical perspective.. Subsequently, we assess, in simulated data sets, the impact of excluding treated individuals and the use of inverse probability weighting (IPW on the estimated model discrimination (c-index and calibration (observed:expected ratio and calibration plots in scenarios with different patterns and effects of treatment use. Results Ignoring the use of effective treatments in a validation data set leads to poorer model discrimination and calibration than would be observed in the untreated target population for the model. Excluding treated individuals provided correct estimates of model performance only when treatment was randomly allocated, although this reduced the precision of the estimates. IPW followed by exclusion of the treated individuals provided correct estimates of model performance in data sets where treatment use was either random or moderately associated with an individual's risk when the assumptions of IPW were met, but yielded incorrect estimates in the presence of non-positivity or an unobserved confounder. Conclusions When validating a prognostic model developed to make predictions of risk without treatment, treatment use in the validation set can bias estimates of the performance of the model in future targeted individuals, and
Czoli, Christine; Da Silva, Michael; Shaul, Randi Zlotnik; d'Agincourt-Canning, Lori; Simpson, Christy; Boydell, Katherine; Rashkovan, Natalie; Vanin, Sharon
2011-10-05
Physician-researchers are bound by professional obligations stemming from both the role of the physician and the role of the researcher. Currently, the dominant models for understanding the relationship between physician-researchers' clinical duties and research duties fit into three categories: the similarity position, the difference position and the middle ground. The law may be said to offer a fourth "model" that is independent from these three categories.These models frame the expectations placed upon physician-researchers by colleagues, regulators, patients and research participants. This paper examines the extent to which the data from semi-structured interviews with 30 physician-researchers at three major pediatric hospitals in Canada reflect these traditional models. It seeks to determine the extent to which existing models align with the described lived experience of the pediatric physician-researchers interviewed.Ultimately, we find that although some physician-researchers make references to something like the weak version of the similarity position, the pediatric-researchers interviewed in this study did not describe their dual roles in a way that tightly mirrors any of the existing theoretical frameworks. We thus conclude that either physician-researchers are in need of better training regarding the nature of the accountability relationships that flow from their dual roles or that models setting out these roles and relationships must be altered to better reflect what we can reasonably expect of physician-researchers in a real-world environment. © 2011 Czoli et al; licensee BioMed Central Ltd.
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Mário Ferreira
2015-12-01
Full Text Available Imperfect detection (i.e., failure to detect a species when the species is present is increasingly recognized as an important source of uncertainty and bias in species distribution modeling. Although methods have been developed to solve this problem by explicitly incorporating variation in detectability in the modeling procedure, their use in freshwater systems remains limited. This is probably because most methods imply repeated sampling (≥ 2 of each location within a short time frame, which may be impractical or too expensive in most studies. Here we explore a novel approach to control for detectability based on the time-to-first-detection, which requires only a single sampling occasion and so may find more general applicability in freshwaters. The approach uses a Bayesian framework to combine conventional occupancy modeling with techniques borrowed from parametric survival analysis, jointly modeling factors affecting the probability of occupancy and the time required to detect a species. To illustrate the method, we modeled large scale factors (elevation, stream order and precipitation affecting the distribution of six fish species in a catchment located in north-eastern Portugal, while accounting for factors potentially affecting detectability at sampling points (stream depth and width. Species detectability was most influenced by depth and to lesser extent by stream width and tended to increase over time for most species. Occupancy was consistently affected by stream order, elevation and annual precipitation. These species presented a widespread distribution with higher uncertainty in tributaries and upper stream reaches. This approach can be used to estimate sampling efficiency and provide a practical framework to incorporate variations in the detection rate in fish distribution models.
Long persistence of rigor mortis at constant low temperature.
Varetto, Lorenzo; Curto, Ombretta
2005-01-06
We studied the persistence of rigor mortis by using physical manipulation. We tested the mobility of the knee on 146 corpses kept under refrigeration at Torino's city mortuary at a constant temperature of +4 degrees C. We found a persistence of complete rigor lasting for 10 days in all the cadavers we kept under observation; and in one case, rigor lasted for 16 days. Between the 11th and the 17th days, a progressively increasing number of corpses showed a change from complete into partial rigor (characterized by partial bending of the articulation). After the 17th day, all the remaining corpses showed partial rigor and in the two cadavers that were kept under observation "à outrance" we found the absolute resolution of rigor mortis occurred on the 28th day. Our results prove that it is possible to find a persistence of rigor mortis that is much longer than the expected when environmental conditions resemble average outdoor winter temperatures in temperate zones. Therefore, this datum must be considered when a corpse is found in those environmental conditions so that when estimating the time of death, we are not misled by the long persistence of rigor mortis.
Rigorous solution to Bargmann-Wigner equation for integer spin
Huang Shi Zhong; Wu Ning; Zheng Zhi Peng
2002-01-01
A rigorous method is developed to solve the Bargamann-Wigner equation for arbitrary integer spin in coordinate representation in a step by step way. The Bargmann-Wigner equation is first transformed to a form easier to solve, the new equations are then solved rigorously in coordinate representation, and the wave functions in a closed form are thus derived
Using grounded theory as a method for rigorously reviewing literature
Wolfswinkel, J.; Furtmueller-Ettinger, Elfriede; Wilderom, Celeste P.M.
2013-01-01
This paper offers guidance to conducting a rigorous literature review. We present this in the form of a five-stage process in which we use Grounded Theory as a method. We first probe the guidelines explicated by Webster and Watson, and then we show the added value of Grounded Theory for rigorously
Evaluating Rigor in Qualitative Methodology and Research Dissemination
Trainor, Audrey A.; Graue, Elizabeth
2014-01-01
Despite previous and successful attempts to outline general criteria for rigor, researchers in special education have debated the application of rigor criteria, the significance or importance of small n research, the purpose of interpretivist approaches, and the generalizability of qualitative empirical results. Adding to these complications, the…
Model of medicines sales forecasting taking into account factors of influence
Kravets, A. G.; Al-Gunaid, M. A.; Loshmanov, V. I.; Rasulov, S. S.; Lempert, L. B.
2018-05-01
The article describes a method for forecasting sales of medicines in conditions of data sampling, which is insufficient for building a model based on historical data alone. The developed method is applicable mainly to new drugs that are already licensed and released for sale but do not yet have stable sales performance in the market. The purpose of this study is to prove the effectiveness of the suggested method forecasting drug sales, taking into account the selected factors of influence, revealed during the review of existing solutions and analysis of the specificity of the area under study. Three experiments were performed on samples of different volumes, which showed an improvement in the accuracy of forecasting sales in small samples.
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Weiguo Li
2012-01-01
Full Text Available A thermodamage strength theoretical model taking into account the effect of residual stress was established and applied to each temperature phase based on the study of effects of various physical mechanisms on the fracture strength of ultrahigh-temperature ceramics. The effects of SiC particle size, crack size, and SiC particle volume fraction on strength corresponding to different temperatures were studied in detail. This study showed that when flaw size is not large, the bigger SiC particle size results in the greater effect of tensile residual stress in the matrix grains on strength reduction, and this prediction coincides with experimental results; and the residual stress and the combined effort of particle size and crack size play important roles in controlling material strength.
REGRESSION MODEL FOR RISK REPORTING IN FINANCIAL STATEMENTS OF ACCOUNTING SERVICES ENTITIES
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Mirela NICHITA
2015-06-01
Full Text Available The purpose of financial reports is to provide useful information to users; the utility of information is defined through the qualitative characteristics (fundamental and enhancing. The financial crisis emphasized the limits of financial reporting which has been unable to prevent investors about the risks they were facing. Due to the current changes in business environment, managers have been highly motivated to rethink and improve the risk governance philosophy, processes and methodologies. The lack of quality, timely data and adequate systems to capture, report and measure the right information across the organization is a fundamental challenge for implementing and sustaining all aspects of effective risk management. Starting with the 80s, the investors are more interested in narratives (Notes to financial statements, than in primary reports (financial position and performance. The research will apply a regression model for assessment of risk reporting by the professional (accounting and taxation services for major companies from Romania during the period 2009 – 2013.
Devinck, Frédéric; Knoblauch, Kenneth
2012-03-21
Establishing the relation between perception and discrimination is a fundamental objective in psychophysics, with the goal of characterizing the neural mechanisms mediating perception. Here, we show that a procedure for estimating a perceptual scale based on a signal detection model also predicts discrimination performance. We use a recently developed procedure, Maximum Likelihood Difference Scaling (MLDS), to measure the perceptual strength of a long-range, color, filling-in phenomenon, the Watercolor Effect (WCE), as a function of the luminance ratio between the two components of its generating contour. MLDS is based on an equal-variance, gaussian, signal detection model and yields a perceptual scale with interval properties. The strength of the fill-in percept increased 10-15 times the estimate of the internal noise level for a 3-fold increase in the luminance ratio. Each observer's estimated scale predicted discrimination performance in a subsequent paired-comparison task. A common signal detection model accounts for both the appearance and discrimination data. Since signal detection theory provides a common metric for relating discrimination performance and neural response, the results have implications for comparing perceptual and neural response functions.
An Improved Car-Following Model Accounting for Impact of Strong Wind
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Dawei Liu
2017-01-01
Full Text Available In order to investigate the effect of strong wind on dynamic characteristic of traffic flow, an improved car-following model based on the full velocity difference model is developed in this paper. Wind force is introduced as the influence factor of car-following behavior. Among three components of wind force, lift force and side force are taken into account. The linear stability analysis is carried out and the stability condition of the newly developed model is derived. Numerical analysis is made to explore the effect of strong wind on spatial-time evolution of a small perturbation. The results show that the strong wind can significantly affect the stability of traffic flow. Driving safety in strong wind is also studied by comparing the lateral force under different wind speeds with the side friction of vehicles. Finally, the fuel consumption of vehicle in strong wind condition is explored and the results show that the fuel consumption decreased with the increase of wind speed.
Duputel, Zacharie; Jiang, Junle; Jolivet, Romain; Simons, Mark; Rivera, Luis; Ampuero, Jean-Paul; Riel, Bryan; Owen, Susan E; Moore, Angelyn W; Samsonov, Sergey V; Ortega Culaciati, Francisco; Minson, Sarah E.
2016-01-01
The subduction zone in northern Chile is a well-identified seismic gap that last ruptured in 1877. On 1 April 2014, this region was struck by a large earthquake following a two week long series of foreshocks. This study combines a wide range of observations, including geodetic, tsunami, and seismic data, to produce a reliable kinematic slip model of the Mw=8.1 main shock and a static slip model of the Mw=7.7 aftershock. We use a novel Bayesian modeling approach that accounts for uncertainty in the Green's functions, both static and dynamic, while avoiding nonphysical regularization. The results reveal a sharp slip zone, more compact than previously thought, located downdip of the foreshock sequence and updip of high-frequency sources inferred by back-projection analysis. Both the main shock and the Mw=7.7 aftershock did not rupture to the trench and left most of the seismic gap unbroken, leaving the possibility of a future large earthquake in the region.
Ay, Jean-Sauveur; Guillemot, Joannès; Martin-StPaul, Nicolas K.; Doyen, Luc; Leadley, Paul
2015-04-01
Species distribution models (SDMs) are widely used to study and predict the outcome of global change on species. In human dominated ecosystems the presence of a given species is the result of both its ecological suitability and human footprint on nature such as land use choices. Land use choices may thus be responsible for a selection bias in the presence/absence data used in SDM calibration. We present a structural modelling approach (i.e. based on structural equation modelling) that accounts for this selection bias. The new structural species distribution model (SSDM) estimates simultaneously land use choices and species responses to bioclimatic variables. A land use equation based on an econometric model of landowner choices was joined to an equation of species response to bioclimatic variables. SSDM allows the residuals of both equations to be dependent, taking into account the possibility of shared omitted variables and measurement errors. We provide a general description of the statistical theory and a set of application on forested trees over France using databases of climate and forest inventory at different spatial resolution (from 2km to 8 km). We also compared the output of the SSDM with outputs of a classical SDM in term of bioclimatic response curves and potential distribution under current climate. According to the species and the spatial resolution of the calibration dataset, shapes of bioclimatic response curves the modelled species distribution maps differed markedly between the SSDM and classical SDMs. The magnitude and directions of these differences were dependent on the correlations between the errors from both equations and were highest for higher spatial resolutions. A first conclusion is that the use of classical SDMs can potentially lead to strong miss-estimation of the actual and future probability of presence modelled. Beyond this selection bias, the SSDM we propose represents a crucial step to account for economic constraints on tree
Accounting comparability and the accuracy of peer-based valuation models
Young, S.; Zeng, Y.
2015-01-01
We examine the link between enhanced accounting comparability and the valuation performance of pricing multiples. Using the warranted multiple method proposed by Bhojraj and Lee (2002, Journal of Accounting Research), we demonstrate how enhanced accounting comparability leads to better peer-based
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Zita Drábková
2013-01-01
Full Text Available Explanatory power of accounting information is the key question for deciding of users of financial statements. A whole range of economic indicators is available to the users of financial statements to measure the firm productivity. When the accounting statements (and applied methods are manipulated, the economic indicators may reveal clearly different results. The users of financial statements should have the possibility to assess the risk of manipulation of accounting statements in time considering potential risk of accounting fraud. The aim of this paper was based on the synthesis of knowledge from the review of literature, the CFEBT model analysis and Beneish Model proposing a convenient model for identifying risks of manipulation of financial statements. The paper summarizes the outcomes of possibilities and limits of manipulated financial statements and their identification. The testing hypothesis is assessing whether there is a close relation of a loss and an increase in the cash flow in 3–5 years time; whether the sum of the amounts for 3–5 year’s time would reveal the same results respectively. The hypothesis was verified on the accounting statements of the accounting entities of prepared case studies respecting the true and fair view of accounting based on Czech accounting standards.
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Antônio Maria Henri Beyle de Araújo
2017-11-01
Full Text Available ABSTRACT A controversy involving loan loss provisions in banks concerns their relationship with the business cycle. While international accounting standards for recognizing provisions (incurred loss model would presumably be pro-cyclical, accentuating the effects of the current economic cycle, an alternative model, the expected loss model, has countercyclical characteristics, acting as a buffer against economic imbalances caused by expansionary or contractionary phases in the economy. In Brazil, a mixed accounting model exists, whose behavior is not known to be pro-cyclical or countercyclical. The aim of this research is to analyze the behavior of these accounting models in relation to the business cycle, using an econometric model consisting of financial and macroeconomic variables. The study allowed us to identify the impact of credit risk behavior, earnings management, capital management, Gross Domestic Product (GDP behavior, and the behavior of the unemployment rate on provisions in countries that use different accounting models. Data from commercial banks in the United Kingdom (incurred loss, in Spain (expected loss, and in Brazil (mixed model were used, covering the period from 2001 to 2012. Despite the accounting models of the three countries being formed by very different rules regarding possible effects on the business cycles, the results revealed a pro-cyclical behavior of provisions in each country, indicating that when GDP grows, provisions tend to fall and vice versa. The results also revealed other factors influencing the behavior of loan loss provisions, such as earning management.
Tavecchia, Giacomo; Miranda, Miguel-Angel; Borrás, David; Bengoa, Mikel; Barceló, Carlos; Paredes-Esquivel, Claudia; Schwarz, Carl
2017-01-01
Aedes albopictus (Diptera; Culicidae) is a highly invasive mosquito species and a competent vector of several arboviral diseases that have spread rapidly throughout the world. Prevalence and patterns of dispersal of the mosquito are of central importance for an effective control of the species. We used site-occupancy models accounting for false negative detections to estimate the prevalence, the turnover, the movement pattern and the growth rate in the number of sites occupied by the mosquito in 17 localities throughout Mallorca Island. Site-occupancy probability increased from 0.35 in the 2012, year of first reported observation of the species, to 0.89 in 2015. Despite a steady increase in mosquito presence, the extinction probability was generally high indicating a high turnover in the occupied sites. We considered two site-dependent covariates, namely the distance from the point of first observation and the estimated yearly occupancy rate in the neighborhood, as predicted by diffusion models. Results suggested that mosquito distribution during the first year was consistent with what predicted by simple diffusion models, but was not consistent with the diffusion model in subsequent years when it was similar to those expected from leapfrog dispersal events. Assuming a single initial colonization event, the spread of Ae. albopictus in Mallorca followed two distinct phases, an early one consistent with diffusion movements and a second consistent with long distance, 'leapfrog', movements. The colonization of the island was fast, with ~90% of the sites estimated to be occupied 3 years after the colonization. The fast spread was likely to have occurred through vectors related to human mobility such as cars or other vehicles. Surveillance and management actions near the introduction point would only be effective during the early steps of the colonization.
A mass-density model can account for the size-weight illusion
Bergmann Tiest, Wouter M.; Drewing, Knut
2018-01-01
When judging the heaviness of two objects with equal mass, people perceive the smaller and denser of the two as being heavier. Despite the large number of theories, covering bottom-up and top-down approaches, none of them can fully account for all aspects of this size-weight illusion and thus for human heaviness perception. Here we propose a new maximum-likelihood estimation model which describes the illusion as the weighted average of two heaviness estimates with correlated noise: One estimate derived from the object’s mass, and the other from the object’s density, with estimates’ weights based on their relative reliabilities. While information about mass can directly be perceived, information about density will in some cases first have to be derived from mass and volume. However, according to our model at the crucial perceptual level, heaviness judgments will be biased by the objects’ density, not by its size. In two magnitude estimation experiments, we tested model predictions for the visual and the haptic size-weight illusion. Participants lifted objects which varied in mass and density. We additionally varied the reliability of the density estimate by varying the quality of either visual (Experiment 1) or haptic (Experiment 2) volume information. As predicted, with increasing quality of volume information, heaviness judgments were increasingly biased towards the object’s density: Objects of the same density were perceived as more similar and big objects were perceived as increasingly lighter than small (denser) objects of the same mass. This perceived difference increased with an increasing difference in density. In an additional two-alternative forced choice heaviness experiment, we replicated that the illusion strength increased with the quality of volume information (Experiment 3). Overall, the results highly corroborate our model, which seems promising as a starting point for a unifying framework for the size-weight illusion and human heaviness
A mass-density model can account for the size-weight illusion.
Wolf, Christian; Bergmann Tiest, Wouter M; Drewing, Knut
2018-01-01
When judging the heaviness of two objects with equal mass, people perceive the smaller and denser of the two as being heavier. Despite the large number of theories, covering bottom-up and top-down approaches, none of them can fully account for all aspects of this size-weight illusion and thus for human heaviness perception. Here we propose a new maximum-likelihood estimation model which describes the illusion as the weighted average of two heaviness estimates with correlated noise: One estimate derived from the object's mass, and the other from the object's density, with estimates' weights based on their relative reliabilities. While information about mass can directly be perceived, information about density will in some cases first have to be derived from mass and volume. However, according to our model at the crucial perceptual level, heaviness judgments will be biased by the objects' density, not by its size. In two magnitude estimation experiments, we tested model predictions for the visual and the haptic size-weight illusion. Participants lifted objects which varied in mass and density. We additionally varied the reliability of the density estimate by varying the quality of either visual (Experiment 1) or haptic (Experiment 2) volume information. As predicted, with increasing quality of volume information, heaviness judgments were increasingly biased towards the object's density: Objects of the same density were perceived as more similar and big objects were perceived as increasingly lighter than small (denser) objects of the same mass. This perceived difference increased with an increasing difference in density. In an additional two-alternative forced choice heaviness experiment, we replicated that the illusion strength increased with the quality of volume information (Experiment 3). Overall, the results highly corroborate our model, which seems promising as a starting point for a unifying framework for the size-weight illusion and human heaviness perception.
Krompecher, T; Bergerioux, C; Brandt-Casadevall, C; Gujer, H R
1983-07-01
The evolution of rigor mortis was studied in cases of nitrogen asphyxia, drowning and strangulation, as well as in fatal intoxications due to strychnine, carbon monoxide and curariform drugs, using a modified method of measurement. Our experiments demonstrated that: (1) Strychnine intoxication hastens the onset and passing of rigor mortis. (2) CO intoxication delays the resolution of rigor mortis. (3) The intensity of rigor may vary depending upon the cause of death. (4) If the stage of rigidity is to be used to estimate the time of death, it is necessary: (a) to perform a succession of objective measurements of rigor mortis intensity; and (b) to verify the eventual presence of factors that could play a role in the modification of its development.
Krompecher, T; Bergerioux, C
1988-01-01
The influence of electrocution on the evolution of rigor mortis was studied on rats. Our experiments showed that: (1) Electrocution hastens the onset of rigor mortis. After an electrocution of 90 s, a complete rigor develops already 1 h post-mortem (p.m.) compared to 5 h p.m. for the controls. (2) Electrocution hastens the passing of rigor mortis. After an electrocution of 90 s, the first significant decrease occurs at 3 h p.m. (8 h p.m. in the controls). (3) These modifications in rigor mortis evolution are less pronounced in the limbs not directly touched by the electric current. (4) In case of post-mortem electrocution, the changes are slightly less pronounced, the resistance is higher and the absorbed energy is lower as compared with the ante-mortem electrocution cases. The results are completed by two practical observations on human electrocution cases.
Carbon accounting of forest bioenergy: from model calibrations to policy options (Invited)
Lamers, P.
2013-12-01
knowledge in the field by comparing different state-of-the-art temporal forest carbon modeling efforts, and discusses whether or to what extent a deterministic ';carbon debt' accounting is possible and appropriate. It concludes upon the possible scientific and eventually political choices in temporal carbon accounting for regulatory frameworks including alternative options to address unintentional carbon losses within forest ecosystems/bioenergy systems.
RIGOROUS GEOREFERENCING OF ALSAT-2A PANCHROMATIC AND MULTISPECTRAL IMAGERY
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I. Boukerch
2013-04-01
Full Text Available The exploitation of the full geometric capabilities of the High-Resolution Satellite Imagery (HRSI, require the development of an appropriate sensor orientation model. Several authors studied this problem; generally we have two categories of geometric models: physical and empirical models. Based on the analysis of the metadata provided with ALSAT-2A, a rigorous pushbroom camera model can be developed. This model has been successfully applied to many very high resolution imagery systems. The relation between the image and ground coordinates by the time dependant collinearity involving many coordinates systems has been tested. The interior orientation parameters must be integrated in the model, the interior parameters can be estimated from the viewing angles corresponding to the pointing directions of any detector, these values are derived from cubic polynomials provided in the metadata. The developed model integrates all the necessary elements with 33 unknown. All the approximate values of the 33 unknowns parameters may be derived from the informations contained in the metadata files provided with the imagery technical specifications or they are simply fixed to zero, so the condition equation is linearized and solved using SVD in a least square sense in order to correct the initial values using a suitable number of well-distributed GCPs. Using Alsat-2A images over the town of Toulouse in the south west of France, three experiments are done. The first is about 2D accuracy analysis using several sets of parameters. The second is about GCPs number and distribution. The third experiment is about georeferencing multispectral image by applying the model calculated from panchromatic image.
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R. Matorras
2015-12-01
Full Text Available The aim of this study was to assess the lifetime economic benefits of assisted reproduction in Spain by calculating the return on this investment. We developed a generational accounting model that simulates the flow of taxes paid by the individual, minus direct government transfers received over the individual’s lifetime. The difference between discounted transfers and taxes minus the cost of either IVF or artificial insemination (AI equals the net fiscal contribution (NFC of a child conceived through assisted reproduction. We conducted sensitivity analysis to test the robustness of our results under various macroeconomic scenarios. A child conceived through assisted reproduction would contribute €370,482 in net taxes to the Spanish Treasury and would receive €275,972 in transfers over their lifetime. Taking into account that only 75% of assisted reproduction pregnancies are successful, the NFC was estimated at €66,709 for IVF-conceived children and €67,253 for AI-conceived children. The return on investment for each euro invested was €15.98 for IVF and €18.53 for AI. The long-term NFC of a child conceived through assisted reproduction could range from €466,379 to €-9,529 (IVF and from €466,923 to €-8,985 (AI. The return on investment would vary between €-2.28 and €111.75 (IVF, and €-2.48 and €128.66 (AI for each euro invested. The break-even point at which the financial position would begin to favour the Spanish Treasury ranges between 29 and 41 years of age. Investment in assisted reproductive techniques may lead to positive discounted future fiscal revenue, notwithstanding its beneficial psychological effect for infertile couples in Spain.
Tomorrow's Research Library: Vigor or Rigor Mortis?
Hacken, Richard D.
1988-01-01
Compares, contrasts, and critiques predictions that have been made about the future of research libraries, focusing on the impact of technology on the library's role and users' needs. The discussion includes models for the adaptation of new technologies that may assist in library planning and change. (38 references) (CLB)
ACCOUNTING HARMONIZATION AND HISTORICAL COST ACCOUNTING
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Valentin Gabriel CRISTEA
2017-05-01
Full Text Available There is a huge interest in accounting harmonization and historical costs accounting, in what they offer us. In this article, different valuation models are discussed. Although one notices the movement from historical cost accounting to fair value accounting, each one has its advantages.
Accounting for Forest Harvest and Wildfire in a Spatially-distributed Carbon Cycle Process Model
Turner, D. P.; Ritts, W.; Kennedy, R. E.; Yang, Z.; Law, B. E.
2009-12-01
Forests are subject to natural disturbances in the form of wildfire, as well as management-related disturbances in the form of timber harvest. These disturbance events have strong impacts on local and regional carbon budgets, but quantifying the associated carbon fluxes remains challenging. The ORCA Project aims to quantify regional net ecosystem production (NEP) and net biome production (NBP) in Oregon, California, and Washington, and we have adopted an integrated approach based on Landsat imagery and ecosystem modeling. To account for stand-level carbon fluxes, the Biome-BGC model has been adapted to simulate multiple severities of fire and harvest. New variables include snags, direct fire emissions, and harvest removals. New parameters include fire-intensity-specific combustion factors for each carbon pool (based on field measurements) and proportional removal rates for harvest events. To quantify regional fluxes, the model is applied in a spatially-distributed mode over the domain of interest, with disturbance history derived from a time series of Landsat images. In stand-level simulations, the post disturbance transition from negative (source) to positive (sink) NEP is delayed approximately a decade in the case of high severity fire compared to harvest. Simulated direct pyrogenic emissions range from 11 to 25 % of total non-soil ecosystem carbon. In spatial mode application over Oregon and California, the sum of annual pyrogenic emissions and harvest removals was generally less that half of total NEP, resulting in significant carbon sequestration on the land base. Spatially and temporally explicit simulation of disturbance-related carbon fluxes will contribute to our ability to evaluate effects of management on regional carbon flux, and in our ability to assess potential biospheric feedbacks to climate change mediated by changing disturbance regimes.
The Charitable Trust Model: An Alternative Approach For Department Of Defense Accounting
2016-12-01
DEFENSE ACCOUNTING 5. FUNDING NUMBERS 6. AUTHOR (S) Gerald V. Weers Jr. 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Postgraduate School...prohibits the incurrence of costs until budget authority is provided; reversing the conditionality of the matching principle accounting logic. In summary...the Board did not believe applying depreciation accounting for these assets would contribute to measuring the cost of outputs produced, or to
International Nuclear Information System (INIS)
Ikawa, K.; Ihara, H.; Nishimura, H.; Tsutsumi, M.; Sawahata, T.
1983-01-01
The study of a near-real-time (n.r.t.) material accountancy system as applied to small or medium-sized spent fuel reprocessing facilities has been carried out since 1978 under the TASTEX programme. In this study, a model of the n.r.t. accountancy system, called the ten-day-detection-time model, was developed and demonstrated in the actual operating plant. The programme was closed on May 1981, but the study has been extended. The effectiveness of the proposed n.r.t. accountancy model was evaluated by means of simulation techniques. The results showed that weekly material balances covering the entire process MBA could provide sufficient information to satisfy the IAEA guidelines for small or medium-sized facilities. The applicability of the model to the actual plant has been evaluated by a series of field tests which covered four campaigns. In addition to the material accountancy data, many valuable operational data with regard to additional locations for an in-process inventory, the time needed for an in-process inventory, etc., have been obtained. A CUMUF (cumulative MUF) chart of the resulting MUF data in the C-1 and C-2 campaigns clearly showed that there had been a measurement bias across the process MBA. This chart gave a dramatic picture of the power of the n.r.t. accountancy concept by showing the nature of this bias, which was not clearly shown in the conventional material accountancy data. (author)
Rigorous derivation of porous-media phase-field equations
Schmuck, Markus; Kalliadasis, Serafim
2017-11-01
The evolution of interfaces in Complex heterogeneous Multiphase Systems (CheMSs) plays a fundamental role in a wide range of scientific fields such as thermodynamic modelling of phase transitions, materials science, or as a computational tool for interfacial flow studies or material design. Here, we focus on phase-field equations in CheMSs such as porous media. To the best of our knowledge, we present the first rigorous derivation of error estimates for fourth order, upscaled, and nonlinear evolution equations. For CheMs with heterogeneity ɛ, we obtain the convergence rate ɛ 1 / 4 , which governs the error between the solution of the new upscaled formulation and the solution of the microscopic phase-field problem. This error behaviour has recently been validated computationally in. Due to the wide range of application of phase-field equations, we expect this upscaled formulation to allow for new modelling, analytic, and computational perspectives for interfacial transport and phase transformations in CheMSs. This work was supported by EPSRC, UK, through Grant Nos. EP/H034587/1, EP/L027186/1, EP/L025159/1, EP/L020564/1, EP/K008595/1, and EP/P011713/1 and from ERC via Advanced Grant No. 247031.
Chen, Dong; Sun, Dihua; Zhao, Min; Zhou, Tong; Cheng, Senlin
2018-07-01
In fact, driving process is a typical cyber physical process which couples tightly the cyber factor of traffic information with the physical components of the vehicles. Meanwhile, the drivers have situation awareness in driving process, which is not only ascribed to the current traffic states, but also extrapolates the changing trend. In this paper, an extended car-following model is proposed to account for drivers' situation awareness. The stability criterion of the proposed model is derived via linear stability analysis. The results show that the stable region of proposed model will be enlarged on the phase diagram compared with previous models. By employing the reductive perturbation method, the modified Korteweg de Vries (mKdV) equation is obtained. The kink-antikink soliton of mKdV equation reveals theoretically the evolution of traffic jams. Numerical simulations are conducted to verify the analytical results. Two typical traffic Scenarios are investigated. The simulation results demonstrate that drivers' situation awareness plays a key role in traffic flow oscillations and the congestion transition.
Associative account of self-cognition: extended forward model and multi-layer structure
Directory of Open Access Journals (Sweden)
Motoaki eSugiura
2013-08-01
Full Text Available The neural correlates of self identified by neuroimaging studies differ depending on which aspects of self are addressed. Here, three categories of self are proposed based on neuroimaging findings and an evaluation of the likely underlying cognitive processes. The physical self, representing self-agency of action, body ownership, and bodily self-recognition, is supported by the sensory and motor association cortices located primarily in the right hemisphere. The interpersonal self, representing the attention or intentions of others directed at the self, is supported by several amodal association cortices in the dorsomedial frontal and lateral posterior cortices. The social self, representing the self as a collection of context-dependent social values, is supported by the ventral aspect of the medial prefrontal cortex and the posterior cingulate cortex. Despite differences in the underlying cognitive processes and neural substrates, all three categories of self are likely to share the computational characteristics of the forward model, which is underpinned by internal schema or learned associations between one’s behavioral output and the consequential input. Additionally, these three categories exist within a hierarchical layer structure based on developmental processes that updates the schema through the attribution of prediction error. In this account, most of the association cortices critically contribute to some aspect of the self through associative learning while the primary regions involved shift from the lateral to the medial cortices in a sequence from the physical to the interpersonal to the social self.
Working memory load and the retro-cue effect: A diffusion model account.
Shepherdson, Peter; Oberauer, Klaus; Souza, Alessandra S
2018-02-01
Retro-cues (i.e., cues presented between the offset of a memory array and the onset of a probe) have consistently been found to enhance performance in working memory tasks, sometimes ameliorating the deleterious effects of increased memory load. However, the mechanism by which retro-cues exert their influence remains a matter of debate. To inform this debate, we applied a hierarchical diffusion model to data from 4 change detection experiments using single item, location-specific probes (i.e., a local recognition task) with either visual or verbal memory stimuli. Results showed that retro-cues enhanced the quality of information entering the decision process-especially for visual stimuli-and decreased the time spent on nondecisional processes. Further, cues interacted with memory load primarily on nondecision time, decreasing or abolishing load effects. To explain these findings, we propose an account whereby retro-cues act primarily to reduce the time taken to access the relevant representation in memory upon probe presentation, and in addition protect cued representations from visual interference. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Monitoring muscle optical scattering properties during rigor mortis
Xia, J.; Ranasinghesagara, J.; Ku, C. W.; Yao, G.
2007-09-01
Sarcomere is the fundamental functional unit in skeletal muscle for force generation. In addition, sarcomere structure is also an important factor that affects the eating quality of muscle food, the meat. The sarcomere structure is altered significantly during rigor mortis, which is the critical stage involved in transforming muscle to meat. In this paper, we investigated optical scattering changes during the rigor process in Sternomandibularis muscles. The measured optical scattering parameters were analyzed along with the simultaneously measured passive tension, pH value, and histology analysis. We found that the temporal changes of optical scattering, passive tension, pH value and fiber microstructures were closely correlated during the rigor process. These results suggested that sarcomere structure changes during rigor mortis can be monitored and characterized by optical scattering, which may find practical applications in predicting meat quality.
Bye, Robin T; Neilson, Peter D
2010-10-01
Physiological tremor during movement is characterized by ∼10 Hz oscillation observed both in the electromyogram activity and in the velocity profile. We propose that this particular rhythm occurs as the direct consequence of a movement response planning system that acts as an intermittent predictive controller operating at discrete intervals of ∼100 ms. The BUMP model of response planning describes such a system. It forms the kernel of Adaptive Model Theory which defines, in computational terms, a basic unit of motor production or BUMP. Each BUMP consists of three processes: (1) analyzing sensory information, (2) planning a desired optimal response, and (3) execution of that response. These processes operate in parallel across successive sequential BUMPs. The response planning process requires a discrete-time interval in which to generate a minimum acceleration trajectory to connect the actual response with the predicted future state of the target and compensate for executional error. We have shown previously that a response planning time of 100 ms accounts for the intermittency observed experimentally in visual tracking studies and for the psychological refractory period observed in double stimulation reaction time studies. We have also shown that simulations of aimed movement, using this same planning interval, reproduce experimentally observed speed-accuracy tradeoffs and movement velocity profiles. Here we show, by means of a simulation study of constant velocity tracking movements, that employing a 100 ms planning interval closely reproduces the measurement discontinuities and power spectra of electromyograms, joint-angles, and angular velocities of physiological tremor reported experimentally. We conclude that intermittent predictive control through sequential operation of BUMPs is a fundamental mechanism of 10 Hz physiological tremor in movement. Copyright © 2010 Elsevier B.V. All rights reserved.
Design of a Competency-Based Assessment Model in the Field of Accounting
Ciudad-Gómez, Adelaida; Valverde-Berrocoso, Jesús
2012-01-01
This paper presents the phases involved in the design of a methodology to contribute both to the acquisition of competencies and to their assessment in the field of Financial Accounting, within the European Higher Education Area (EHEA) framework, which we call MANagement of COMpetence in the areas of Accounting (MANCOMA). Having selected and…
A rigorous derivation of gravitational self-force
International Nuclear Information System (INIS)
Gralla, Samuel E; Wald, Robert M
2008-01-01
There is general agreement that the MiSaTaQuWa equations should describe the motion of a 'small body' in general relativity, taking into account the leading order self-force effects. However, previous derivations of these equations have made a number of ad hoc assumptions and/or contain a number of unsatisfactory features. For example, all previous derivations have invoked, without proper justification, the step of 'Lorenz gauge relaxation', wherein the linearized Einstein equation is written in the form appropriate to the Lorenz gauge, but the Lorenz gauge condition is then not imposed-thereby making the resulting equations for the metric perturbation inequivalent to the linearized Einstein equations. (Such a 'relaxation' of the linearized Einstein equations is essential in order to avoid the conclusion that 'point particles' move on geodesics.) In this paper, we analyze the issue of 'particle motion' in general relativity in a systematic and rigorous way by considering a one-parameter family of metrics, g ab (λ), corresponding to having a body (or black hole) that is 'scaled down' to zero size and mass in an appropriate manner. We prove that the limiting worldline of such a one-parameter family must be a geodesic of the background metric, g ab (λ = 0). Gravitational self-force-as well as the force due to coupling of the spin of the body to curvature-then arises as a first-order perturbative correction in λ to this worldline. No assumptions are made in our analysis apart from the smoothness and limit properties of the one-parameter family of metrics, g ab (λ). Our approach should provide a framework for systematically calculating higher order corrections to gravitational self-force, including higher multipole effects, although we do not attempt to go beyond first-order calculations here. The status of the MiSaTaQuWa equations is explained
Rigorous covariance propagation of geoid errors to geodetic MDT estimates
Pail, R.; Albertella, A.; Fecher, T.; Savcenko, R.
2012-04-01
The mean dynamic topography (MDT) is defined as the difference between the mean sea surface (MSS) derived from satellite altimetry, averaged over several years, and the static geoid. Assuming geostrophic conditions, from the MDT the ocean surface velocities as important component of global ocean circulation can be derived from it. Due to the availability of GOCE gravity field models, for the very first time MDT can now be derived solely from satellite observations (altimetry and gravity) down to spatial length-scales of 100 km and even below. Global gravity field models, parameterized in terms of spherical harmonic coefficients, are complemented by the full variance-covariance matrix (VCM). Therefore, for the geoid component a realistic statistical error estimate is available, while the error description of the altimetric component is still an open issue and is, if at all, attacked empirically. In this study we make the attempt to perform, based on the full gravity VCM, rigorous error propagation to derived geostrophic surface velocities, thus also considering all correlations. For the definition of the static geoid we use the third release of the time-wise GOCE model, as well as the satellite-only combination model GOCO03S. In detail, we will investigate the velocity errors resulting from the geoid component in dependence of the harmonic degree, and the impact of using/no using covariances on the MDT errors and its correlations. When deriving an MDT, it is spectrally filtered to a certain maximum degree, which is usually driven by the signal content of the geoid model, by applying isotropic or non-isotropic filters. Since this filtering is acting also on the geoid component, the consistent integration of this filter process into the covariance propagation shall be performed, and its impact shall be quantified. The study will be performed for MDT estimates in specific test areas of particular oceanographic interest.
Recent Development in Rigorous Computational Methods in Dynamical Systems
Arai, Zin; Kokubu, Hiroshi; Pilarczyk, Paweł
2009-01-01
We highlight selected results of recent development in the area of rigorous computations which use interval arithmetic to analyse dynamical systems. We describe general ideas and selected details of different ways of approach and we provide specific sample applications to illustrate the effectiveness of these methods. The emphasis is put on a topological approach, which combined with rigorous calculations provides a broad range of new methods that yield mathematically rel...
International Nuclear Information System (INIS)
Thomas, C.C. Jr.; Ostenak, C.A.; Gutmacher, R.G.; Dayem, H.A.; Kern, E.A.
1981-04-01
A model of an operating conversion and purification process for the production of reactor-grade plutonium dioxide was developed as the first component in the design and evaluation of a nuclear materials measurement and accountability system. The model accurately simulates process operation and can be used to identify process problems and to predict the effect of process modifications
Efstratiadis, Andreas; Nalbantis, Ioannis; Rozos, Evangelos; Koutsoyiannis, Demetris
2010-05-01
In mixed natural and artificialized river basins, many complexities arise due to anthropogenic interventions in the hydrological cycle, including abstractions from surface water bodies, groundwater pumping or recharge and water returns through drainage systems. Typical engineering approaches adopt a multi-stage modelling procedure, with the aim to handle the complexity of process interactions and the lack of measured abstractions. In such context, the entire hydrosystem is separated into natural and artificial sub-systems or components; the natural ones are modelled individually, and their predictions (i.e. hydrological fluxes) are transferred to the artificial components as inputs to a water management scheme. To account for the interactions between the various components, an iterative procedure is essential, whereby the outputs of the artificial sub-systems (i.e. abstractions) become inputs to the natural ones. However, this strategy suffers from multiple shortcomings, since it presupposes that pure natural sub-systems can be located and that sufficient information is available for each sub-system modelled, including suitable, i.e. "unmodified", data for calibrating the hydrological component. In addition, implementing such strategy is ineffective when the entire scheme runs in stochastic simulation mode. To cope with the above drawbacks, we developed a generalized modelling framework, following a network optimization approach. This originates from the graph theory, which has been successfully implemented within some advanced computer packages for water resource systems analysis. The user formulates a unified system which is comprised of the hydrographical network and the typical components of a water management network (aqueducts, pumps, junctions, demand nodes etc.). Input data for the later include hydraulic properties, constraints, targets, priorities and operation costs. The real-world system is described through a conceptual graph, whose dummy properties
Gilbertson, Keith
2002-01-01
Standard utilities can help you collect and interpret your Linux system's process accounting data. Describes the uses of process accounting, standard process accounting commands, and example code that makes use of process accounting utilities.
Rigorous vector wave propagation for arbitrary flat media
Bos, Steven P.; Haffert, Sebastiaan Y.; Keller, Christoph U.
2017-08-01
Precise modelling of the (off-axis) point spread function (PSF) to identify geometrical and polarization aberrations is important for many optical systems. In order to characterise the PSF of the system in all Stokes parameters, an end-to-end simulation of the system has to be performed in which Maxwell's equations are rigorously solved. We present the first results of a python code that we are developing to perform multiscale end-to-end wave propagation simulations that include all relevant physics. Currently we can handle plane-parallel near- and far-field vector diffraction effects of propagating waves in homogeneous isotropic and anisotropic materials, refraction and reflection of flat parallel surfaces, interference effects in thin films and unpolarized light. We show that the code has a numerical precision on the order of 10-16 for non-absorbing isotropic and anisotropic materials. For absorbing materials the precision is on the order of 10-8. The capabilities of the code are demonstrated by simulating a converging beam reflecting from a flat aluminium mirror at normal incidence.
International Nuclear Information System (INIS)
Xavier, Roberto Salles
2014-01-01
The regimes of accountability, the organizations of global governance and institutional arrangements of global governance of nuclear non-proliferation and of Mutual Vigilance Brazilian-Argentine of Nuclear Safeguards are the subject of research. The starting point is the importance of the institutional model of global governance for the effective control of non-proliferation of nuclear weapons. In this context, the research investigates how to structure the current arrangements of the international nuclear non-proliferation and what is the performance of model Mutual Vigilance Brazilian-Argentine of Nuclear Safeguards in relation to accountability regimes of global governance. For that, was searched the current literature of three theoretical dimensions: accountability, global governance and global governance organizations. In relation to the research method was used the case study and the treatment technique of data the analysis of content. The results allowed: to establish an evaluation model based on accountability mechanisms; to assess how behaves the model Mutual Vigilance Brazilian-Argentine Nuclear Safeguards front of the proposed accountability regime; and to measure the degree to which regional arrangements that work with systems of global governance can strengthen these international systems. (author)
Account of the Pauli principle in the quasiparticle-phonon nuclear model
International Nuclear Information System (INIS)
Molina, Kh.L.
1980-01-01
The correlation effects in the ground states of even-even deformed nuclei on their one- and two-phonon states are studied in terms of the semimicroscopic nuclear theory. A secular equation for one-phonon excitations is derived, which take into account, in average, exact commutation relations between quasiparticle operators. It is demonstrated, that the account of the correlation in the ground state can significantly influence the values of the wave function two-phonon components
Heil, Peter; Matysiak, Artur; Neubauer, Heinrich
2017-09-01
Thresholds for detecting sounds in quiet decrease with increasing sound duration in every species studied. The neural mechanisms underlying this trade-off, often referred to as temporal integration, are not fully understood. Here, we probe the human auditory system with a large set of tone stimuli differing in duration, shape of the temporal amplitude envelope, duration of silent gaps between bursts, and frequency. Duration was varied by varying the plateau duration of plateau-burst (PB) stimuli, the duration of the onsets and offsets of onset-offset (OO) stimuli, and the number of identical bursts of multiple-burst (MB) stimuli. Absolute thresholds for a large number of ears (>230) were measured using a 3-interval-3-alternative forced choice (3I-3AFC) procedure. Thresholds decreased with increasing sound duration in a manner that depended on the temporal envelope. Most commonly, thresholds for MB stimuli were highest followed by thresholds for OO and PB stimuli of corresponding durations. Differences in the thresholds for MB and OO stimuli and in the thresholds for MB and PB stimuli, however, varied widely across ears, were negative in some ears, and were tightly correlated. We show that the variation and correlation of MB-OO and MB-PB threshold differences are linked to threshold microstructure, which affects the relative detectability of the sidebands of the MB stimuli and affects estimates of the bandwidth of auditory filters. We also found that thresholds for MB stimuli increased with increasing duration of the silent gaps between bursts. We propose a new model and show that it accurately accounts for our results and does so considerably better than a leaky-integrator-of-intensity model and a probabilistic model proposed by others. Our model is based on the assumption that sensory events are generated by a Poisson point process with a low rate in the absence of stimulation and higher, time-varying rates in the presence of stimulation. A subject in a 3I-3AFC
Accounting Faculty Internships
Directory of Open Access Journals (Sweden)
Jill Christopher
2013-06-01
Full Text Available Accounting professionals, business college accrediting bodies, and even accounting academics themselves acknowledge that there is a disconnect between academe and the rigors and requirements of the accounting profession. Among the suggestions proposed in the literature to reduce this gap is the faculty internship, where accounting faculty members work within the field as accountants. Heretofore, individual case studies report benefits of such internships that accrue to a variety of stakeholder groups beyond just the faculty intern and include the academic institution, students, and accounting profession through faculty internships. This research seeks wider support for these benefits. This descriptive study involved surveying a sample of accounting faculty members to get their opinions about the benefits and drawbacks of faculty internships, and to determine the level of use of faculty internships in accounting. In all, 128 usable responses were obtained, representing a 14.6% response rate. The results of this study reveal that although most faculty members acknowledge the benefits cited in the literature, too few take advantage of faculty internships.
International Nuclear Information System (INIS)
Górecki, K; Zarȩbski, J
2014-01-01
The paper is devoted to modelling thermal properties of semiconductor devices at the steady state. The dc thermal model of a semiconductor device taking into account the multipath heat flow is proposed. Some results of calculations and measurements of thermal resistance of a power MOSFET operating at different cooling conditions are presented. The obtained results of calculations fit the results of measurements, which proves the correctness of the proposed model.
Tenderness of pre- and post rigor lamb longissimus muscle.
Geesink, Geert; Sujang, Sadi; Koohmaraie, Mohammad
2011-08-01
Lamb longissimus muscle (n=6) sections were cooked at different times post mortem (prerigor, at rigor, 1dayp.m., and 7 days p.m.) using two cooking methods. Using a boiling waterbath, samples were either cooked to a core temperature of 70 °C or boiled for 3h. The latter method was meant to reflect the traditional cooking method employed in countries where preparation of prerigor meat is practiced. The time postmortem at which the meat was prepared had a large effect on the tenderness (shear force) of the meat (PCooking prerigor and at rigor meat to 70 °C resulted in higher shear force values than their post rigor counterparts at 1 and 7 days p.m. (9.4 and 9.6 vs. 7.2 and 3.7 kg, respectively). The differences in tenderness between the treatment groups could be largely explained by a difference in contraction status of the meat after cooking and the effect of ageing on tenderness. Cooking pre and at rigor meat resulted in severe muscle contraction as evidenced by the differences in sarcomere length of the cooked samples. Mean sarcomere lengths in the pre and at rigor samples ranged from 1.05 to 1.20 μm. The mean sarcomere length in the post rigor samples was 1.44 μm. Cooking for 3 h at 100 °C did improve the tenderness of pre and at rigor prepared meat as compared to cooking to 70 °C, but not to the extent that ageing did. It is concluded that additional intervention methods are needed to improve the tenderness of prerigor cooked meat. Copyright © 2011 Elsevier B.V. All rights reserved.
Bourgeois-Gironde , Sacha; Giraud , Raphaël
2005-01-01
We suscribe to an account of framing-effects in decision theory in terms of an inference to a background informationa by the hearer when a speaker uses a certain frame while other equivalent frames were also available. This account was sketched by Craig McKenzie. We embed it in Bolker-Jeffrey decision model (or logic of action) - one main reason of this is that this latter model makes preferences bear on propositions. We can deduce a given anomaly or cognitive bias (namely framing-effects) in...
Franco-Pérez, Marco; Gázquez, José L; Ayers, Paul W; Vela, Alberto
2018-02-13
The temperature-dependence of the Helmholtz free energy with respect to the number of electrons is analyzed within the framework of the Grand Canonical Ensemble. At the zero-temperature limit, the Helmholtz free energy behaves as a Heaviside function of the number of electrons; however, as the temperature increases, the profile smoothens and exhibits a minimum value at noninteger positive values of the fractional electronic charge. We show that the exact average electronic energy as a function of the number of electrons does not display this feature at any temperature, since this behavior is solely due to the electronic entropy. Our mathematical analysis thus indicates that the widely used parabolic interpolation model should not be viewed as an approximation for the average electronic energy, but for the dependence of the Helmholtz free energy upon the number of electrons, and this analysis is corroborated by numerical results. Finally, an electrophilicity index is defined for the Helmholtz free energy showing that, for a given chemical species, there exists a temperature value for which this quantity is equivalent to the electrophilicity index defined within the parabolic interpolation of the electronic energy as a function of the number of electrons. Our formulation suggests that the convexity property of the energy versus the number of electrons together with the entropic contribution does not allow for an analogous nucleophilicity index to be defined.
Thiry, Olivier; Winckelmans, Grégoire
2016-02-01
In the large-eddy simulation (LES) of turbulent flows, models are used to account for the subgrid-scale (SGS) stress. We here consider LES with "truncation filtering only" (i.e., that due to the LES grid), thus without regular explicit filtering added. The SGS stress tensor is then composed of two terms: the cross term that accounts for interactions between resolved scales and unresolved scales, and the Reynolds term that accounts for interactions between unresolved scales. Both terms provide forward- (dissipation) and backward (production, also called backscatter) energy transfer. Purely dissipative, eddy-viscosity type, SGS models are widely used: Smagorinsky-type models, or more advanced multiscale-type models. Dynamic versions have also been developed, where the model coefficient is determined using a dynamic procedure. Being dissipative by nature, those models do not provide backscatter. Even when using the dynamic version with local averaging, one typically uses clipping to forbid negative values of the model coefficient and hence ensure the stability of the simulation; hence removing the backscatter produced by the dynamic procedure. More advanced SGS model are thus desirable, and that better conform to the physics of the true SGS stress, while remaining stable. We here investigate, in decaying homogeneous isotropic turbulence, and using a de-aliased pseudo-spectral method, the behavior of the cross term and of the Reynolds term: in terms of dissipation spectra, and in terms of probability density function (pdf) of dissipation in physical space: positive and negative (backscatter). We then develop a new mixed model that better accounts for the physics of the SGS stress and for the backscatter. It has a cross term part which is built using a scale-similarity argument, further combined with a correction for Galilean invariance using a pseudo-Leonard term: this is the term that also does backscatter. It also has an eddy-viscosity multiscale model part that
Estimation of the breaking of rigor mortis by myotonometry.
Vain, A; Kauppila, R; Vuori, E
1996-05-31
Myotonometry was used to detect breaking of rigor mortis. The myotonometer is a new instrument which measures the decaying oscillations of a muscle after a brief mechanical impact. The method gives two numerical parameters for rigor mortis, namely the period and decrement of the oscillations, both of which depend on the time period elapsed after death. In the case of breaking the rigor mortis by muscle lengthening, both the oscillation period and decrement decreased, whereas, shortening the muscle caused the opposite changes. Fourteen h after breaking the stiffness characteristics of the right and left m. biceps brachii, or oscillation periods, were assimilated. However, the values for decrement of the muscle, reflecting the dissipation of mechanical energy, maintained their differences.
International Nuclear Information System (INIS)
Voronov, V.V.; Dang, N.D.
1984-01-01
the system of equations, enabling to calculate the energy and the structure of excited states, described by the wave function, containing one- and two-phon components was obtained in the framework of quasiparticlephonon model. The requirements of Pauli principle for two-phonon components and phonon correlation in the ground nucleus state are taken into account
Woodill, G.; Barbier, R.R.; Fiamingo, C.
2010-01-01
Traditional, combat model based analysis of Dismounted Combatant Operations (DCO) has focused on the ‘lethal’ aspects in an engagement, and to a limited extent the environment in which the engagement takes place. These are however only two of the factors that should be taken into account when
Current-account effects of a devaluation in an optimizing model with capital accumulation
DEFF Research Database (Denmark)
Nielsen, Søren Bo
1991-01-01
short, the devaluation is bound to improve the current account on impact, whereas this will deteriorate in the case of a long contract period, and the more so the smaller are adjustment costs in investment. In addition, we study the consequences for the terms of trade and for the stocks of foreign...
Webster, Robert L.; Hammond, Kevin L.; Rothwell, James C.
2013-01-01
This manuscript is part of a stream of continuing research examining market orientation within higher education and its potential impact on organizational performance. The organizations researched are business schools and the data collected came from chairpersons of accounting departments of AACSB member business schools. We use a reworded Narver…
Tompkins, Adrian M; Ermert, Volker
2013-02-18
The relative roles of climate variability and population related effects in malaria transmission could be better understood if regional-scale dynamical malaria models could account for these factors. A new dynamical community malaria model is introduced that accounts for the temperature and rainfall influences on the parasite and vector life cycles which are finely resolved in order to correctly represent the delay between the rains and the malaria season. The rainfall drives a simple but physically based representation of the surface hydrology. The model accounts for the population density in the calculation of daily biting rates. Model simulations of entomological inoculation rate and circumsporozoite protein rate compare well to data from field studies from a wide range of locations in West Africa that encompass both seasonal endemic and epidemic fringe areas. A focus on Bobo-Dioulasso shows the ability of the model to represent the differences in transmission rates between rural and peri-urban areas in addition to the seasonality of malaria. Fine spatial resolution regional integrations for Eastern Africa reproduce the malaria atlas project (MAP) spatial distribution of the parasite ratio, and integrations for West and Eastern Africa show that the model grossly reproduces the reduction in parasite ratio as a function of population density observed in a large number of field surveys, although it underestimates malaria prevalence at high densities probably due to the neglect of population migration. A new dynamical community malaria model is publicly available that accounts for climate and population density to simulate malaria transmission on a regional scale. The model structure facilitates future development to incorporate migration, immunity and interventions.
Bulygin, Y. I.; Koronchik, D. A.; Legkonogikh, A. N.; Zharkova, M. G.; Azimova, N. N.
2017-05-01
The standard k-epsilon turbulence model, adapted for welding workshops, equipped with fixed workstations with sources of pollution took into account only the convective component of heat transfer, which is quite reasonable for large-volume rooms (with low density distribution of sources of pollution) especially the results of model calculations taking into account only the convective component correlated well with experimental data. For the purposes of this study, when we are dealing with a small confined space where necessary to take account of the body heated to a high temperature (for welding), located next to each other as additional sources of heat, it can no longer be neglected radiative heat exchange. In the task - to experimentally investigate the various types of heat transfer in a limited closed space for welding and behavior of a mathematical model, describing the contribution of the various components of the heat exchange, including radiation, influencing the formation of fields of concentration, temperature, air movement and thermal stress in the test environment. Conducted field experiments to model cubic body, allowing you to configure and debug the model of heat and mass transfer processes with the help of the developed approaches, comparing the measurement results of air flow velocity and temperature with the calculated data showed qualitative and quantitative agreement between process parameters, that is an indicator of the adequacy of heat and mass transfer model.
International Nuclear Information System (INIS)
Ihara, Hitoshi; Ikawa, Koji
1986-11-01
An assessment was done on the potential capability of a Near-Real-Time materials accountancy system for a model plutonium conversion plant. To this end, a computer simulation system, DYSAS-C, has been developed and evaluated through this assessment study. This study showed that N.R.T.A system could be used not only as a good operator's accounting system but also as a useful inspectorate's system to detect an abrupt diversion. It also showed, however, that more elaborated NRTA system which have not yet evaluated in this study should be considerered when we wish to improve of detecting protracted diversion. (author)
Application of the rigorous method to x-ray and neutron beam scattering on rough surfaces
International Nuclear Information System (INIS)
Goray, Leonid I.
2010-01-01
The paper presents a comprehensive numerical analysis of x-ray and neutron scattering from finite-conducting rough surfaces which is performed in the frame of the boundary integral equation method in a rigorous formulation for high ratios of characteristic dimension to wavelength. The single integral equation obtained involves boundary integrals of the single and double layer potentials. A more general treatment of the energy conservation law applicable to absorption gratings and rough mirrors is considered. In order to compute the scattering intensity of rough surfaces using the forward electromagnetic solver, Monte Carlo simulation is employed to average the deterministic diffraction grating efficiency due to individual surfaces over an ensemble of realizations. Some rules appropriate for numerical implementation of the theory at small wavelength-to-period ratios are presented. The difference between the rigorous approach and approximations can be clearly seen in specular reflectances of Au mirrors with different roughness parameters at wavelengths where grazing incidence occurs at close to or larger than the critical angle. This difference may give rise to wrong estimates of rms roughness and correlation length if they are obtained by comparing experimental data with calculations. Besides, the rigorous approach permits taking into account any known roughness statistics and allows exact computation of diffuse scattering.
Modeling of normal contact of elastic bodies with surface relief taken into account
Goryacheva, I. G.; Tsukanov, I. Yu
2018-04-01
An approach to account the surface relief in normal contact problems for rough bodies on the basis of an additional displacement function for asperities is considered. The method and analytic expressions for calculating the additional displacement function for one-scale and two-scale wavy relief are presented. The influence of the microrelief geometric parameters, including the number of scales and asperities density, on additional displacements of the rough layer is analyzed.
Accounting for Slipping and Other False Negatives in Logistic Models of Student Learning
MacLellan, Christopher J.; Liu, Ran; Koedinger, Kenneth R.
2015-01-01
Additive Factors Model (AFM) and Performance Factors Analysis (PFA) are two popular models of student learning that employ logistic regression to estimate parameters and predict performance. This is in contrast to Bayesian Knowledge Tracing (BKT) which uses a Hidden Markov Model formalism. While all three models tend to make similar predictions,…
Bier, Martin; Brak, Bastiaan
2015-04-01
In the Netherlands there has been nationwide vaccination against the measles since 1976. However, in small clustered communities of orthodox Protestants there is widespread refusal of the vaccine. After 1976, three large outbreaks with about 3000 reported cases of the measles have occurred among these orthodox Protestants. The outbreaks appear to occur about every twelve years. We show how a simple Kermack-McKendrick-like model can quantitatively account for the periodic outbreaks. Approximate analytic formulae to connect the period, size, and outbreak duration are derived. With an enhanced model we take the latency period in account. We also expand the model to follow how different age groups are affected. Like other researchers using other methods, we conclude that large scale underreporting of the disease must occur.
Reconciling the Rigor-Relevance Dilemma in Intellectual Capital Research
Andriessen, Daniel
2004-01-01
This paper raises the issue of research methodology for intellectual capital and other types of management research by focusing on the dilemma of rigour versus relevance. The more traditional explanatory approach to research often leads to rigorous results that are not of much help to solve practical problems. This paper describes an alternative…
Paper 3: Content and Rigor of Algebra Credit Recovery Courses
Walters, Kirk; Stachel, Suzanne
2014-01-01
This paper describes the content, organization and rigor of the f2f and online summer algebra courses that were delivered in summers 2011 and 2012. Examining the content of both types of courses is important because research suggests that algebra courses with certain features may be better than others in promoting success for struggling students.…
A rigorous treatment of uncertainty quantification for Silicon damage metrics
International Nuclear Information System (INIS)
Griffin, P.
2016-01-01
These report summaries the contributions made by Sandia National Laboratories in support of the International Atomic Energy Agency (IAEA) Nuclear Data Section (NDS) Technical Meeting (TM) on Nuclear Reaction Data and Uncertainties for Radiation Damage. This work focused on a rigorous treatment of the uncertainties affecting the characterization of the displacement damage seen in silicon semiconductors. (author)
Effects of post mortem temperature on rigor tension, shortening and ...
African Journals Online (AJOL)
Fully developed rigor mortis in muscle is characterised by maximum loss of extensibility. The course of post mortem changes in ostrich muscle was studied by following isometric tension, shortening and change in pH during the first 24 h post mortem within muscle strips from the muscularis gastrocnemius, pars interna at ...
Characterization of rigor mortis of longissimus dorsi and triceps ...
African Journals Online (AJOL)
24 h) of the longissimus dorsi (LD) and triceps brachii (TB) muscles as well as the shear force (meat tenderness) and colour were evaluated, aiming at characterizing the rigor mortis in the meat during industrial processing. Data statistic treatment demonstrated that carcass temperature and pH decreased gradually during ...
Rigor, vigor, and the study of health disparities.
Adler, Nancy; Bush, Nicole R; Pantell, Matthew S
2012-10-16
Health disparities research spans multiple fields and methods and documents strong links between social disadvantage and poor health. Associations between socioeconomic status (SES) and health are often taken as evidence for the causal impact of SES on health, but alternative explanations, including the impact of health on SES, are plausible. Studies showing the influence of parents' SES on their children's health provide evidence for a causal pathway from SES to health, but have limitations. Health disparities researchers face tradeoffs between "rigor" and "vigor" in designing studies that demonstrate how social disadvantage becomes biologically embedded and results in poorer health. Rigorous designs aim to maximize precision in the measurement of SES and health outcomes through methods that provide the greatest control over temporal ordering and causal direction. To achieve precision, many studies use a single SES predictor and single disease. However, doing so oversimplifies the multifaceted, entwined nature of social disadvantage and may overestimate the impact of that one variable and underestimate the true impact of social disadvantage on health. In addition, SES effects on overall health and functioning are likely to be greater than effects on any one disease. Vigorous designs aim to capture this complexity and maximize ecological validity through more complete assessment of social disadvantage and health status, but may provide less-compelling evidence of causality. Newer approaches to both measurement and analysis may enable enhanced vigor as well as rigor. Incorporating both rigor and vigor into studies will provide a fuller understanding of the causes of health disparities.
A rigorous proof for the Landauer-Büttiker formula
DEFF Research Database (Denmark)
Cornean, Horia Decebal; Jensen, Arne; Moldoveanu, V.
Recently, Avron et al. shed new light on the question of quantum transport in mesoscopic samples coupled to particle reservoirs by semi-infinite leads. They rigorously treat the case when the sample undergoes an adiabatic evolution thus generating a current through th leads, and prove the so call...
International Nuclear Information System (INIS)
Kato, Tomoko; Ishiguro, Katsuhiko; Naito, Morimasa; Ikeda, Takao; Little, Richard
2001-03-01
In the safety assessment of a high-level radioactive waste (HLW) disposal system, it is required to estimate radiological impacts on future human beings arising from potential radionuclide releases from a deep repository into the surface environment. In order to estimated the impacts, a biosphere model is developed by reasonably assuming radionuclide migration processes in the surface environment and relevant human lifestyles. It is important to modify the present biosphere models or to develop alternative biosphere models applying the biosphere models according to quality and quantify of the information acquired through the siting process for constructing the repository. In this study, alternative biosphere models were developed taking geosphere-biosphere interface of marine environment into account. Moreover, the flux to dose conversion factors calculated by these alternative biosphere models was compared with those by the present basic biosphere models. (author)
Pras, Aiko; van Beijnum, Bernhard J.F.; Sprenkels, Ron; Parhonyi, R.
2001-01-01
This article provides an introduction to Internet accounting and discusses the status of related work within the IETF and IRTF, as well as certain research projects. Internet accounting is different from accounting in POTS. To understand Internet accounting, it is important to answer questions like
Miyazaki, Hideki T; Miyazaki, Hiroshi; Miyano, Kenjiro
2003-09-01
We have recently identified the resonant scattering from dielectric bispheres in the specular direction, which has long been known as the specular resonance, to be a type of rainbow (a caustic) and a general phenomenon for bispheres. We discuss the details of the specular resonance on the basis of systematic calculations. In addition to the rigorous theory, which precisely describes the scattering even in the resonance regime, the ray-tracing method, which gives the scattering in the geometrical-optics limit, is used. Specular resonance is explicitly defined as strong scattering in the direction of the specular reflection from the symmetrical axis of the bisphere whose intensity exceeds that of the scattering from noninteracting bispheres. Then the range of parameters for computing a particular specular resonance is specified. This resonance becomes prominent in a wide range of refractive indices (from 1.2 to 2.2) in a wide range of size parameters (from five to infinity) and for an arbitrarily polarized light incident within an angle of 40 degrees to the symmetrical axis. This particular scattering can stay evident even when the spheres are not in contact or the sizes of the spheres are different. Thus specular resonance is a common and robust phenomenon in dielectric bispheres. Furthermore, we demonstrate that various characteristic features in the scattering from bispheres can be explained successfully by using intuitive and simple representations. Most of the significant scatterings other than the specular resonance are also understandable as caustics in geometrical-optics theory. The specular resonance becomes striking at the smallest size parameter among these caustics because its optical trajectory is composed of only the refractions at the surfaces and has an exceptionally large intensity. However, some characteristics are not accounted for by geometrical optics. In particular, the oscillatory behaviors of their scattering intensity are well described by
Account of the effect of nuclear collision cascades in model of radiation damage of RPV steels
International Nuclear Information System (INIS)
Kevorkyan, Yu.R.; Nikolaev, Yu.A.
1997-01-01
A kinetic model is proposed for describing the effect of collision cascades in model of radiation damage of reactor pressure vessel steels. This is a closed system of equations which can be solved only by numerical methods in general case
Factors accounting for youth suicide attempt in Hong Kong: a model building.
Wan, Gloria W Y; Leung, Patrick W L
2010-10-01
This study aimed at proposing and testing a conceptual model of youth suicide attempt. We proposed a model that began with family factors such as a history of physical abuse and parental divorce/separation. Family relationship, presence of psychopathology, life stressors, and suicide ideation were postulated as mediators, leading to youth suicide attempt. The stepwise entry of the risk factors to a logistic regression model defined their proximity as related to suicide attempt. Path analysis further refined our proposed model of youth suicide attempt. Our originally proposed model was largely confirmed. The main revision was dropping parental divorce/separation as a risk factor in the model due to lack of significant contribution when examined alongside with other risk factors. This model was cross-validated by gender. This study moved research on youth suicide from identification of individual risk factors to model building, integrating separate findings of the past studies.
Yu. A. Rounov; O. G. Shirokov; D. I. Zalizny; D. M. Los
2004-01-01
The paper proposes a thermal model of a power oil-immersed transformer as a system of four homogeneous bodies: winding, oil, core and cooling medium. On the basis of experimental data it is shown that such model describes more precisely actual thermal processes taking place in a transformer than the thermal model accepted in GOST 14209-85.
Directory of Open Access Journals (Sweden)
Yu. A. Rounov
2004-01-01
Full Text Available The paper proposes a thermal model of a power oil-immersed transformer as a system of four homogeneous bodies: winding, oil, core and cooling medium. On the basis of experimental data it is shown that such model describes more precisely actual thermal processes taking place in a transformer than the thermal model accepted in GOST 14209-85.
Accounting for subgrid scale topographic variations in flood propagation modeling using MODFLOW
DEFF Research Database (Denmark)
Milzow, Christian; Kinzelbach, W.
2010-01-01
To be computationally viable, grid-based spatially distributed hydrological models of large wetlands or floodplains must be set up using relatively large cells (order of hundreds of meters to kilometers). Computational costs are especially high when considering the numerous model runs or model time...
Modelling of the application of near real time accountancy and process monitoring to plants
International Nuclear Information System (INIS)
Huddleston, J.; Stockwell, M.K.
1983-09-01
Many statistical tests have been proposed for the analysis of accountancy data from nuclear fuel reprocessing plants. The purpose of this programme was to assess the performance of these tests by applying them to data streams which simulate the information that would be available from a real plant. In addition the problems of pre-processing the raw data from a plant were considered. A suite of programs to analyse the data has been written, which include colour graphical output to allow effective interpretation of the results. The commercial software package VisiCalc has been evaluated and found to be effective for the rapid production of material balances from plant data. (author)
Rigorous simulations of a helical core fiber by the use of transformation optics formalism.
Napiorkowski, Maciej; Urbanczyk, Waclaw
2014-09-22
We report for the first time on rigorous numerical simulations of a helical-core fiber by using a full vectorial method based on the transformation optics formalism. We modeled the dependence of circular birefringence of the fundamental mode on the helix pitch and analyzed the effect of a birefringence increase caused by the mode displacement induced by a core twist. Furthermore, we analyzed the complex field evolution versus the helix pitch in the first order modes, including polarization and intensity distribution. Finally, we show that the use of the rigorous vectorial method allows to better predict the confinement loss of the guided modes compared to approximate methods based on equivalent in-plane bending models.
Nikoloulopoulos, Aristidis K
2017-10-01
A bivariate copula mixed model has been recently proposed to synthesize diagnostic test accuracy studies and it has been shown that it is superior to the standard generalized linear mixed model in this context. Here, we call trivariate vine copulas to extend the bivariate meta-analysis of diagnostic test accuracy studies by accounting for disease prevalence. Our vine copula mixed model includes the trivariate generalized linear mixed model as a special case and can also operate on the original scale of sensitivity, specificity, and disease prevalence. Our general methodology is illustrated by re-analyzing the data of two published meta-analyses. Our study suggests that there can be an improvement on trivariate generalized linear mixed model in fit to data and makes the argument for moving to vine copula random effects models especially because of their richness, including reflection asymmetric tail dependence, and computational feasibility despite their three dimensionality.
THE CURRENT ACCOUNT DEFICIT AND THE FIXED EXCHANGE RATE. ADJUSTING MECHANISMS AND MODELS.
Directory of Open Access Journals (Sweden)
HATEGAN D.B. Anca
2010-07-01
Full Text Available The main purpose of the paper is to explain what measures can be taken in order to fix the trade deficit, and the pressure that is upon a country by imposing such measures. The international and the national supply and demand conditions change rapidly, and if a country doesn’t succeed in keeping a tight control over its deficit, a lot of factors will affect its wellbeing. In order to reduce the external trade deficit, the government needs to resort to several techniques. The desired result is to have a balanced current account, and therefore, the government is free to use measures such as fixing its exchange rate, reducing government spending etc. We have shown that all these measures will have a certain impact upon an economy, by allowing its exports to thrive and eliminate the danger from excessive imports, or vice-versa. The main conclusion our paper is that government intervention is allowed in order to maintain the balance of the current account.
Accounting for spatial effects in land use regression for urban air pollution modeling.
Bertazzon, Stefania; Johnson, Markey; Eccles, Kristin; Kaplan, Gilaad G
2015-01-01
In order to accurately assess air pollution risks, health studies require spatially resolved pollution concentrations. Land-use regression (LUR) models estimate ambient concentrations at a fine spatial scale. However, spatial effects such as spatial non-stationarity and spatial autocorrelation can reduce the accuracy of LUR estimates by increasing regression errors and uncertainty; and statistical methods for resolving these effects--e.g., spatially autoregressive (SAR) and geographically weighted regression (GWR) models--may be difficult to apply simultaneously. We used an alternate approach to address spatial non-stationarity and spatial autocorrelation in LUR models for nitrogen dioxide. Traditional models were re-specified to include a variable capturing wind speed and direction, and re-fit as GWR models. Mean R(2) values for the resulting GWR-wind models (summer: 0.86, winter: 0.73) showed a 10-20% improvement over traditional LUR models. GWR-wind models effectively addressed both spatial effects and produced meaningful predictive models. These results suggest a useful method for improving spatially explicit models. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
Rigorous Integration of Non-Linear Ordinary Differential Equations in Chebyshev Basis
Czech Academy of Sciences Publication Activity Database
Dzetkulič, Tomáš
2015-01-01
Roč. 69, č. 1 (2015), s. 183-205 ISSN 1017-1398 R&D Projects: GA MŠk OC10048; GA ČR GD201/09/H057 Institutional research plan: CEZ:AV0Z10300504 Keywords : Initial value problem * Rigorous integration * Taylor model * Chebyshev basis Subject RIV: IN - Informatics, Computer Science Impact factor: 1.366, year: 2015
An extended two-lane car-following model accounting for inter-vehicle communication
Ou, Hui; Tang, Tie-Qiao
2018-04-01
In this paper, we develop a novel car-following model with inter-vehicle communication to explore each vehicle's movement in a two-lane traffic system when an incident occurs on a lane. The numerical results show that the proposed model can perfectly describe each vehicle's motion when an incident occurs, i.e., no collision occurs while the classical full velocity difference (FVD) model produces collision on each lane, which shows the proposed model is more reasonable. The above results can help drivers to reasonably adjust their driving behaviors when an incident occurs in a two-lane traffic system.
Modelling reverse characteristics of power LEDs with thermal phenomena taken into account
International Nuclear Information System (INIS)
Ptak, Przemysław; Górecki, Krzysztof
2016-01-01
This paper refers to modelling characteristics of power LEDs with a particular reference to thermal phenomena. Special attention is paid to modelling characteristics of the circuit protecting the considered device against the excessive value of the reverse voltage and to the description of the temperature influence on optical power. The network form of the worked out model is presented and some results of experimental verification of this model for the selected diodes operating at different cooling conditions are described. The very good agreement between the calculated and measured characteristics is obtained
Accounting for correlated observations in an age-based state-space stock assessment model
DEFF Research Database (Denmark)
Berg, Casper Willestofte; Nielsen, Anders
2016-01-01
Fish stock assessment models often relyon size- or age-specific observations that are assumed to be statistically independent of each other. In reality, these observations are not raw observations, but rather they are estimates from a catch-standardization model or similar summary statistics base...... the independence assumption is rejected. Less fluctuating estimates of the fishing mortality is obtained due to a reduced process error. The improved model does not suffer from correlated residuals unlike the independent model, and the variance of forecasts is decreased....
Eremin, Yu. A.; Sveshnikov, A. G.
2018-04-01
The discrete source method is used to develop and implement a mathematical model for solving the problem of scattering electromagnetic waves by a three-dimensional plasmonic scatterer with nonlocal effects taken into account. Numerical results are presented whereby the features of the scattering properties of plasmonic particles with allowance for nonlocal effects are demonstrated depending on the direction and polarization of the incident wave.
Degeling, Koen; IJzerman, Maarten J.; Koopman, Miriam; Koffijberg, Hendrik
2017-01-01
Background Parametric distributions based on individual patient data can be used to represent both stochastic and parameter uncertainty. Although general guidance is available on how parameter uncertainty should be accounted for in probabilistic sensitivity analysis, there is no comprehensive guidance on reflecting parameter uncertainty in the (correlated) parameters of distributions used to represent stochastic uncertainty in patient-level models. This study aims to provide this guidance by ...
Mathematical model of rod oscillations with account of material relaxation behaviour
Kudinov, I. V.; Kudinov, V. A.; Eremin, A. V.; Zhukov, V. V.
2018-03-01
Taking into account the bounded velocity of strains and deformations propagation in the formula given in the Hooke’s law, the authors have obtained the differential equation of rod damped oscillations that includes the first and the third time derivatives of displacement as well as the mixed derivative (with respect to space and time variables). Study of its precise analytical solution found by means of separation of variables has shown that rod recovery after being disturbed is accompanied by low-amplitude damped oscillations that occur at the start time and only within the range of positive displacement values. The oscillations amplitude decreases with increase of relaxation factor. Rod is recovered virtually without an oscillating process both in the limit and with any high values of the relaxation factor.
Directory of Open Access Journals (Sweden)
Obidimma Ezezika
2009-10-01
Full Text Available There is skepticism and resistance to innovations associated with agro-biotechnology projects, leading to the possibility of failure. The source of the skepticism is complex, but partly traceable to how local communities view genetically engineered crops, public perception on the technology’s implications, and views on the role of the private sector in public health and agriculture, especially in the developing world. We posit that a governance and management model in which ethical, social, cultural, and commercialization issues are accounted for and addressed is important in mitigating risk of project failure and improving the appropriate adoption of agro-biotechnology in sub-Saharan Africa. We introduce a social audit model, which we term Ethical, Social, Cultural and Commercialization (ESC2 auditing and which we developed based on feedback from a number of stakeholders. We lay the foundation for its importance in agro-biotechnology development projects and show how the model can be applied to projects run by Public Private Partnerships. We argue that the implementation of the audit model can help to build public trust through facilitating project accountability and transparency. The model also provides evidence on how ESC2 issues are perceived by various stakeholders, which enables project managers to effectively monitor and improve project performance. Although this model was specifically designed for agro-biotechnology initiatives, we show how it can also be applied to other development projects.
Assessing and accounting for time heterogeneity in stochastic actor oriented models
Lospinoso, Joshua A.; Schweinberger, Michael; Snijders, Tom A. B.; Ripley, Ruth M.
This paper explores time heterogeneity in stochastic actor oriented models (SAOM) proposed by Snijders (Sociological methodology. Blackwell, Boston, pp 361-395, 2001) which are meant to study the evolution of networks. SAOMs model social networks as directed graphs with nodes representing people,
Bioeconomic Modelling of Wetlands and Waterfowl in Western Canada: Accounting for Amenity Values
Kooten, van G.C.; Whitey, P.; Wong, L.
2011-01-01
This study reexamines and updates an original bioeconomic model of optimal duck harvest and wetland retention by Hammack and Brown (1974, Waterfowl and Wetlands: Toward Bioeconomic Analysis. Washington, DC: Resources for the Future). It then extends the model to include the nonmarket (in situ) value
Mohr, D.C.; Cuijpers, P.; Lehman, K.A.
2011-01-01
The effectiveness of and adherence to eHealth interventions is enhanced by human support. However, human support has largely not been manualized and has usually not been guided by clear models. The objective of this paper is to develop a clear theoretical model, based on relevant empirical
An individual-based model of Zebrafish population dynamics accounting for energy dynamics
DEFF Research Database (Denmark)
Beaudouin, Remy; Goussen, Benoit; Piccini, Benjamin
2015-01-01
Developing population dynamics models for zebrafish is crucial in order to extrapolate from toxicity data measured at the organism level to biological levels relevant to support and enhance ecological risk assessment. To achieve this, a dynamic energy budget for individual zebrafish (DEB model...
THE DISTRIBUTION MODELING OF IMPURITIES IN THE ATMOSPHERE WITH TAKING INTO ACCOUNT OF TERRAIN
Directory of Open Access Journals (Sweden)
P. B. Mashyhina
2009-03-01
Full Text Available The 2D numerical model to simulate the pollutant dispersion over complex terrain was proposed. The model is based on the equation of potential flow and the equation of admixture transfer. Results of the numerical experiment are presented.
Jang, S.; Rasouli, S.; Timmermans, H.J.P.
2016-01-01
Recently, regret-based choice models have been introduced in the travel behavior research community as an alternative to expected/random utility models. The fundamental proposition underlying regret theory is that individuals minimize the amount of regret they (are expected to) experience when
We describe the development and evaluation of two new model algorithms for NOx chemistry in the R-LINE near-road dispersion model for traffic sources. With increased urbanization, there is increased mobility leading to higher amount of traffic related activity on a global scale. ...
Ren, Sicong; Mazière, Matthieu; Forest, Samuel; Morgeneyer, Thilo F.; Rousselier, Gilles
2017-12-01
One of the most successful models for describing the Portevin-Le Chatelier effect in engineering applications is the Kubin-Estrin-McCormick model (KEMC). In the present work, the influence of dynamic strain ageing on dynamic recovery due to dislocation annihilation is introduced in order to improve the KEMC model. This modification accounts for additional strain hardening rate due to limited dislocation annihilation by the diffusion of solute atoms and dislocation pinning at low strain rate and/or high temperature. The parameters associated with this novel formulation are identified based on tensile tests for a C-Mn steel at seven temperatures ranging from 20 °C to 350 °C. The validity of the model and the improvement compared to existing models are tested using 2D and 3D finite element simulations of the Portevin-Le Chatelier effect in tension.
Investigation of a new model accounting for rotors of finite tip-speed ratio in yaw or tilt
International Nuclear Information System (INIS)
Branlard, E; Gaunaa, M; Machefaux, E
2014-01-01
The main results from a recently developed vortex model are implemented into a Blade Element Momentum(BEM) code. This implementation accounts for the effect of finite tip-speed ratio, an effect which was not considered in standard BEM yaw-models. The model and its implementation are presented. Data from the MEXICO experiment are used as a basis for validation. Three tools using the same 2D airfoil coefficient data are compared: a BEM code, an Actuator-Line and a vortex code. The vortex code is further used to validate the results from the newly implemented BEM yaw-model. Significant improvements are obtained for the prediction of loads and induced velocities. Further relaxation of the main assumptions of the model are briefly presented and discussed
An improved car-following model accounting for the preceding car's taillight
Zhang, Jian; Tang, Tie-Qiao; Yu, Shao-Wei
2018-02-01
During the deceleration process, the preceding car's taillight may have influences on its following car's driving behavior. In this paper, we propose an extended car-following model with consideration of the preceding car's taillight. Two typical situations are used to simulate each car's movement and study the effects of the preceding car's taillight on the driving behavior. Meanwhile, sensitivity analysis of the model parameter is in detail discussed. The numerical results show that the proposed model can improve the stability of traffic flow and the traffic safety can be enhanced without a decrease of efficiency especially when cars pass through a signalized intersection.
DEFF Research Database (Denmark)
Verhey, Jesko L.; Mauermann, Manfred; Epp, Bastian
2017-01-01
For normal-hearing listeners, auditory pure-tone thresholds in quiet often show quasi periodic fluctuations when measured with a high frequency resolution, referred to as threshold fine structure. Threshold fine structure is dependent on the stimulus duration, with smaller fluctuations for short...... than for long signals. The present study demonstrates how this effect can be captured by a nonlinear and active model of the cochlear in combination with a temporal integration stage. Since this cochlear model also accounts for fine structure and connected level dependent effects, it is superior...
Directory of Open Access Journals (Sweden)
Tzanko Georgiev
2009-03-01
Full Text Available This article deals with synthesis of dynamic unstructured model of variable volume fed-batch fermentation process with intensive droppings for L-valine production. The presented approach of the investigation includes the following main procedures: description of the process by generalized stoichiometric equations; preliminary data processing and calculation of specific rates for main kinetic variables; identification of the specific rates takes into account the dissolved oxygen tension; establishment and optimisation of dynamic model of the process; simulation researches. MATLAB is used as a research environment.
Einstein's Theory A Rigorous Introduction for the Mathematically Untrained
Grøn, Øyvind
2011-01-01
This book provides an introduction to the theory of relativity and the mathematics used in its processes. Three elements of the book make it stand apart from previously published books on the theory of relativity. First, the book starts at a lower mathematical level than standard books with tensor calculus of sufficient maturity to make it possible to give detailed calculations of relativistic predictions of practical experiments. Self-contained introductions are given, for example vector calculus, differential calculus and integrations. Second, in-between calculations have been included, making it possible for the non-technical reader to follow step-by-step calculations. Thirdly, the conceptual development is gradual and rigorous in order to provide the inexperienced reader with a philosophically satisfying understanding of the theory. Einstein's Theory: A Rigorous Introduction for the Mathematically Untrained aims to provide the reader with a sound conceptual understanding of both the special and genera...
Rigor mortis in an unusual position: Forensic considerations.
D'Souza, Deepak H; Harish, S; Rajesh, M; Kiran, J
2011-07-01
We report a case in which the dead body was found with rigor mortis in an unusual position. The dead body was lying on its back with limbs raised, defying gravity. Direction of the salivary stains on the face was also defying the gravity. We opined that the scene of occurrence of crime is unlikely to be the final place where the dead body was found. The clues were revealing a homicidal offence and an attempt to destroy the evidence. The forensic use of 'rigor mortis in an unusual position' is in furthering the investigations, and the scientific confirmation of two facts - the scene of death (occurrence) is different from the scene of disposal of dead body, and time gap between the two places.
Some rigorous results concerning spectral theory for ideal MHD
International Nuclear Information System (INIS)
Laurence, P.
1986-01-01
Spectral theory for linear ideal MHD is laid on a firm foundation by defining appropriate function spaces for the operators associated with both the first- and second-order (in time and space) partial differential operators. Thus, it is rigorously established that a self-adjoint extension of F(xi) exists. It is shown that the operator L associated with the first-order formulation satisfies the conditions of the Hille--Yosida theorem. A foundation is laid thereby within which the domains associated with the first- and second-order formulations can be compared. This allows future work in a rigorous setting that will clarify the differences (in the two formulations) between the structure of the generalized eigenspaces corresponding to the marginal point of the spectrum ω = 0
Some rigorous results concerning spectral theory for ideal MHD
International Nuclear Information System (INIS)
Laurence, P.
1985-05-01
Spectral theory for linear ideal MHD is laid on a firm foundation by defining appropriate function spaces for the operators associated with both the first and second order (in time and space) partial differential operators. Thus, it is rigorously established that a self-adjoint extension of F(xi) exists. It is shown that the operator L associated with the first order formulation satisfies the conditions of the Hille-Yosida theorem. A foundation is laid thereby within which the domains associated with the first and second order formulations can be compared. This allows future work in a rigorous setting that will clarify the differences (in the two formulations) between the structure of the generalized eigenspaces corresponding to the marginal point of the spectrum ω = 0
Accounting for scattering in the Landauer-Datta-Lundstrom transport model
Directory of Open Access Journals (Sweden)
Юрій Олексійович Кругляк
2015-03-01
Full Text Available Scattering of carriers in the LDL transport model during the changes of the scattering times in the collision processes is considered qualitatively. The basic relationship between the transmission coefficient T and the average mean free path is derived for 1D conductor. As an example, the experimental data for Si MOSFET are analyzed with the use of various models of reliability.
Loading Processes Dynamics Modelling Taking into Account the Bucket-Soil Interaction
Directory of Open Access Journals (Sweden)
Carmen Debeleac
2007-10-01
Full Text Available The author propose three dynamic models specialized for the vibrations and resistive forces analysis that appear at the loading process with different construction equipment like frontal loaders and excavators.The models used putting into evidence the components of digging: penetration, cutting, and loading.The conclusions of this study consist by evidentiate the dynamic overloads that appear on the working state and that induced the self-oscillations into the equipment structure.
BENNIS, M; DE BUHAN, P
2003-01-01
A two-phase continuum description of reinforced soil structures is proposed in which the soil mass and the reinforcement network are treated as mutually interacting superposed media. The equations governing such a model are developed in the context of elastoplasticity, with special emphasis put on the soil/reinforcement interaction constitutive law. As shown in an illustrative example, such a model paves the way for numerically efficient design methods of reinforced soil structures.
DEFF Research Database (Denmark)
Kiil, Søren
2017-01-01
The purpose of this work is to develop a mathematical model that can quantify the dispersion of pigments, with a focus on the mechanical breakage of pigment agglomerates. The underlying physical mechanism was assumed to be surface erosion of spherical pigment agglomerates. The full agglomerate pa.......g., in the development of novel dispersion principles and for analysis of dispersion failures. The general applicability of the model, beyond the three pigments considered, needs to be confirmed....
A Rigorous Methodology for Analyzing and Designing Plug-Ins
DEFF Research Database (Denmark)
Fasie, Marieta V.; Haxthausen, Anne Elisabeth; Kiniry, Joseph
2013-01-01
. This paper addresses these problems by describing a rigorous methodology for analyzing and designing plug-ins. The methodology is grounded in the Extended Business Object Notation (EBON) and covers informal analysis and design of features, GUI, actions, and scenarios, formal architecture design, including...... behavioral semantics, and validation. The methodology is illustrated via a case study whose focus is an Eclipse environment for the RAISE formal method's tool suite....
Striation Patterns of Ox Muscle in Rigor Mortis
Locker, Ronald H.
1959-01-01
Ox muscle in rigor mortis offers a selection of myofibrils fixed at varying degrees of contraction from sarcomere lengths of 3.7 to 0.7 µ. A study of this material by phase contrast and electron microscopy has revealed four distinct successive patterns of contraction, including besides the familiar relaxed and contracture patterns, two intermediate types (2.4 to 1.9 µ, 1.8 to 1.5 µ) not previously well described. PMID:14417790
Rigorous Analysis of a Randomised Number Field Sieve
Lee, Jonathan; Venkatesan, Ramarathnam
2018-01-01
Factorisation of integers $n$ is of number theoretic and cryptographic significance. The Number Field Sieve (NFS) introduced circa 1990, is still the state of the art algorithm, but no rigorous proof that it halts or generates relationships is known. We propose and analyse an explicitly randomised variant. For each $n$, we show that these randomised variants of the NFS and Coppersmith's multiple polynomial sieve find congruences of squares in expected times matching the best-known heuristic e...
Reciprocity relations in transmission electron microscopy: A rigorous derivation.
Krause, Florian F; Rosenauer, Andreas
2017-01-01
A concise derivation of the principle of reciprocity applied to realistic transmission electron microscopy setups is presented making use of the multislice formalism. The equivalence of images acquired in conventional and scanning mode is thereby rigorously shown. The conditions for the applicability of the found reciprocity relations is discussed. Furthermore the positions of apertures in relation to the corresponding lenses are considered, a subject which scarcely has been addressed in previous publications. Copyright Â© 2016 Elsevier Ltd. All rights reserved.
John Burns; Martin Quinn; Liz Warren; João Oliveira
2013-01-01
Overview of the BookThe textbook comprises six sections which together represent a comprehensive insight into management accounting - its technical attributes, changeable wider context, and the multiple roles of management accountants. The sections cover: (1) an introduction to management accounting, (2) how organizations account for their costs, (3) the importance of tools and techniques which assist organizational planning and control, (4) the various dimensions of making business decisions...
An extended continuum model accounting for the driver's timid and aggressive attributions
International Nuclear Information System (INIS)
Cheng, Rongjun; Ge, Hongxia; Wang, Jufeng
2017-01-01
Considering the driver's timid and aggressive behaviors simultaneously, a new continuum model is put forwarded in this paper. By applying the linear stability theory, we presented the analysis of new model's linear stability. Through nonlinear analysis, the KdV–Burgers equation is derived to describe density wave near the neutral stability line. Numerical results verify that aggressive driving is better than timid act because the aggressive driver will adjust his speed timely according to the leading car's speed. The key improvement of this new model is that the timid driving deteriorates traffic stability while the aggressive driving will enhance traffic stability. The relationship of energy consumption between the aggressive and timid driving is also studied. Numerical results show that aggressive driver behavior can not only suppress the traffic congestion but also reduce the energy consumption. - Highlights: • A new continuum model is developed with the consideration of the driver's timid and aggressive behaviors simultaneously. • Applying the linear stability theory, the new model's linear stability is obtained. • Through nonlinear analysis, the KdV–Burgers equation is derived. • The energy consumption for this model is studied.
Carbon accounting and economic model uncertainty of emissions from biofuels-induced land use change.
Plevin, Richard J; Beckman, Jayson; Golub, Alla A; Witcover, Julie; O'Hare, Michael
2015-03-03
Few of the numerous published studies of the emissions from biofuels-induced "indirect" land use change (ILUC) attempt to propagate and quantify uncertainty, and those that have done so have restricted their analysis to a portion of the modeling systems used. In this study, we pair a global, computable general equilibrium model with a model of greenhouse gas emissions from land-use change to quantify the parametric uncertainty in the paired modeling system's estimates of greenhouse gas emissions from ILUC induced by expanded production of three biofuels. We find that for the three fuel systems examined--US corn ethanol, Brazilian sugar cane ethanol, and US soybean biodiesel--95% of the results occurred within ±20 g CO2e MJ(-1) of the mean (coefficient of variation of 20-45%), with economic model parameters related to crop yield and the productivity of newly converted cropland (from forestry and pasture) contributing most of the variance in estimated ILUC emissions intensity. Although the experiments performed here allow us to characterize parametric uncertainty, changes to the model structure have the potential to shift the mean by tens of grams of CO2e per megajoule and further broaden distributions for ILUC emission intensities.
An extended continuum model accounting for the driver's timid and aggressive attributions
Energy Technology Data Exchange (ETDEWEB)
Cheng, Rongjun; Ge, Hongxia [Faculty of Maritime and Transportation, Ningbo University, Ningbo 315211 (China); Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies, Nanjing 210096 (China); National Traffic Management Engineering and Technology Research Centre Ningbo University Sub-centre, Ningbo 315211 (China); Wang, Jufeng, E-mail: wjf@nit.zju.edu.cn [Ningbo Institute of Technology, Zhejiang University, Ningbo 315100 (China)
2017-04-18
Considering the driver's timid and aggressive behaviors simultaneously, a new continuum model is put forwarded in this paper. By applying the linear stability theory, we presented the analysis of new model's linear stability. Through nonlinear analysis, the KdV–Burgers equation is derived to describe density wave near the neutral stability line. Numerical results verify that aggressive driving is better than timid act because the aggressive driver will adjust his speed timely according to the leading car's speed. The key improvement of this new model is that the timid driving deteriorates traffic stability while the aggressive driving will enhance traffic stability. The relationship of energy consumption between the aggressive and timid driving is also studied. Numerical results show that aggressive driver behavior can not only suppress the traffic congestion but also reduce the energy consumption. - Highlights: • A new continuum model is developed with the consideration of the driver's timid and aggressive behaviors simultaneously. • Applying the linear stability theory, the new model's linear stability is obtained. • Through nonlinear analysis, the KdV–Burgers equation is derived. • The energy consumption for this model is studied.
Modelling the long term alteration of concretes: taking carbonation into account
International Nuclear Information System (INIS)
Badouix, Franck
1999-01-01
After an introduction on the storage and warehousing of wastes from the nuclear industry (principles and objectives, general historic context, classification of radioactive wastes), an overview of studies performed within the CEA on wastes (activities related to the fuel cycle, research on warehousing and storage materials), and an introduction to the development of a general code of simulation of the degradation of cement matrix material and of a modelling of concrete carbonation under water, this research thesis reports a bibliographical study on the following topics: case of a non-altered hydrated concrete, expertise performed on altered materials on industrial sites, alteration of CPA-CEM I paste (alteration by demineralized water, carbonation). Based on these observations, a simplified model is developed for the cross diffusion of calcium and carbonates in a semi-infinite inert porous matrix of portlandite. This model is used to simulate degradations performed in laboratory on a CPA-CEM I paste. This model reveals to be insufficient as far as carbonation is concerned. Tests are performed to study the influence of granulates on a concrete (from an industrial site or elaborated in laboratory with a known composition) in water with low mineral content. A model is developed to understand the behaviour of paste-granulate interfaces. Then, concretes are lixiviated in carbonated water, and by using previous results and the simplified modelling of carbonation, simulations are performed and compared with experimental results [fr
Alibrahim, Abdullah; Wu, Shinyi
2018-03-01
Accountable care organizations (ACO) in the United States show promise in controlling health care costs while preserving patients' choice of providers. Understanding the effects of patient choice is critical in novel payment and delivery models like ACO that depend on continuity of care and accountability. The financial, utilization, and behavioral implications associated with a patient's decision to forego local health care providers for more distant ones to access higher quality care remain unknown. To study this question, we used an agent-based simulation model of a health care market composed of providers able to form ACO serving patients and embedded it in a conditional logit decision model to examine patients capable of choosing their care providers. This simulation focuses on Medicare beneficiaries and their congestive heart failure (CHF) outcomes. We place the patient agents in an ACO delivery system model in which provider agents decide if they remain in an ACO and perform a quality improving CHF disease management intervention. Illustrative results show that allowing patients to choose their providers reduces the yearly payment per CHF patient by $320, reduces mortality rates by 0.12 percentage points and hospitalization rates by 0.44 percentage points, and marginally increases provider participation in ACO. This study demonstrates a model capable of quantifying the effects of patient choice in a theoretical ACO system and provides a potential tool for policymakers to understand implications of patient choice and assess potential policy controls.
Zendehrouh, Sareh
2015-11-01
Recent work on decision-making field offers an account of dual-system theory for decision-making process. This theory holds that this process is conducted by two main controllers: a goal-directed system and a habitual system. In the reinforcement learning (RL) domain, the habitual behaviors are connected with model-free methods, in which appropriate actions are learned through trial-and-error experiences. However, goal-directed behaviors are associated with model-based methods of RL, in which actions are selected using a model of the environment. Studies on cognitive control also suggest that during processes like decision-making, some cortical and subcortical structures work in concert to monitor the consequences of decisions and to adjust control according to current task demands. Here a computational model is presented based on dual system theory and cognitive control perspective of decision-making. The proposed model is used to simulate human performance on a variant of probabilistic learning task. The basic proposal is that the brain implements a dual controller, while an accompanying monitoring system detects some kinds of conflict including a hypothetical cost-conflict one. The simulation results address existing theories about two event-related potentials, namely error related negativity (ERN) and feedback related negativity (FRN), and explore the best account of them. Based on the results, some testable predictions are also presented. Copyright © 2015 Elsevier Ltd. All rights reserved.
Valari, Myrto; Menut, Laurent; Chatignoux, Edouard
2011-02-01
Environmental epidemiology and more specifically time-series analysis have traditionally used area-averaged pollutant concentrations measured at central monitors as exposure surrogates to associate health outcomes with air pollution. However, spatial aggregation has been shown to contribute to the overall bias in the estimation of the exposure-response functions. This paper presents the benefit of adding features of the spatial variability of exposure by using concentration fields modeled with a chemistry transport model instead of monitor data and accounting for human activity patterns. On the basis of county-level census data for the city of Paris, France, and a Monte Carlo simulation, a simple activity model was developed accounting for the temporal variability between working and evening hours as well as during transit. By combining activity data with modeled concentrations, the downtown, suburban, and rural spatial patterns in exposure to nitrogen dioxide, ozone, and PM2.5 (particulate matter [PM] pollution on total nonaccidental mortality for the 4-yr period from 2001 to 2004. It was shown that the time series of the exposure surrogates developed here are less correlated across co-pollutants than in the case of the area-averaged monitor data. This led to less biased exposure-response functions when all three co-pollutants were inserted simultaneously in the same regression model. This finding yields insight into pollutant-specific health effects that are otherwise masked by the high correlation among co-pollutants.
Stellinga, B.; Mügge, D.
2014-01-01
The European and global regulation of accounting standards have witnessed remarkable changes over the past twenty years. In the early 1990s, EU accounting practices were fragmented along national lines and US accounting standards were the de facto global standards. Since 2005, all EU listed
Linhartová, Lucie
2012-01-01
This thesis gives a complex view on accounting outsourcing, deals with the outsourcing process from its beginning (condition of collaboration, making of contract), through collaboration to its possible ending. This work defines outsourcing, indicates the main advatages, disadvatages and arguments for its using. The main object of thesis is mainly practical side of accounting outsourcing and providing of first quality accounting services.
Critical Analysis of Strategies for Determining Rigor in Qualitative Inquiry.
Morse, Janice M
2015-09-01
Criteria for determining the trustworthiness of qualitative research were introduced by Guba and Lincoln in the 1980s when they replaced terminology for achieving rigor, reliability, validity, and generalizability with dependability, credibility, and transferability. Strategies for achieving trustworthiness were also introduced. This landmark contribution to qualitative research remains in use today, with only minor modifications in format. Despite the significance of this contribution over the past four decades, the strategies recommended to achieve trustworthiness have not been critically examined. Recommendations for where, why, and how to use these strategies have not been developed, and how well they achieve their intended goal has not been examined. We do not know, for example, what impact these strategies have on the completed research. In this article, I critique these strategies. I recommend that qualitative researchers return to the terminology of social sciences, using rigor, reliability, validity, and generalizability. I then make recommendations for the appropriate use of the strategies recommended to achieve rigor: prolonged engagement, persistent observation, and thick, rich description; inter-rater reliability, negative case analysis; peer review or debriefing; clarifying researcher bias; member checking; external audits; and triangulation. © The Author(s) 2015.
Tylutki, Zofia; Mendyk, Aleksander; Polak, Sebastian
2018-04-01
Modern model-based approaches to cardiac safety and efficacy assessment require accurate drug concentration-effect relationship establishment. Thus, knowledge of the active concentration of drugs in heart tissue is desirable along with inter-subject variability influence estimation. To that end, we developed a mechanistic physiologically based pharmacokinetic model of the heart. The models were described with literature-derived parameters and written in R, v.3.4.0. Five parameters were estimated. The model was fitted to amitriptyline and nortriptyline concentrations after an intravenous infusion of amitriptyline. The cardiac model consisted of 5 compartments representing the pericardial fluid, heart extracellular water, and epicardial intracellular, midmyocardial intracellular, and endocardial intracellular fluids. Drug cardiac metabolism, passive diffusion, active efflux, and uptake were included in the model as mechanisms involved in the drug disposition within the heart. The model accounted for inter-individual variability. The estimates of optimized parameters were within physiological ranges. The model performance was verified by simulating 5 clinical studies of amitriptyline intravenous infusion, and the simulated pharmacokinetic profiles agreed with clinical data. The results support the model feasibility. The proposed structure can be tested with the goal of improving the patient-specific model-based cardiac safety assessment and offers a framework for predicting cardiac concentrations of various xenobiotics. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.
Estimation of the time since death--reconsidering the re-establishment of rigor mortis.
Anders, Sven; Kunz, Michaela; Gehl, Axel; Sehner, Susanne; Raupach, Tobias; Beck-Bornholdt, Hans-Peter
2013-01-01
In forensic medicine, there is an undefined data background for the phenomenon of re-establishment of rigor mortis after mechanical loosening, a method used in establishing time since death in forensic casework that is thought to occur up to 8 h post-mortem. Nevertheless, the method is widely described in textbooks on forensic medicine. We examined 314 joints (elbow and knee) of 79 deceased at defined time points up to 21 h post-mortem (hpm). Data were analysed using a random intercept model. Here, we show that re-establishment occurred in 38.5% of joints at 7.5 to 19 hpm. Therefore, the maximum time span for the re-establishment of rigor mortis appears to be 2.5-fold longer than thought so far. These findings have major impact on the estimation of time since death in forensic casework.
Hubbard, Rebecca A; Johnson, Eric; Chubak, Jessica; Wernli, Karen J; Kamineni, Aruna; Bogart, Andy; Rutter, Carolyn M
2017-06-01
Exposures derived from electronic health records (EHR) may be misclassified, leading to biased estimates of their association with outcomes of interest. An example of this problem arises in the context of cancer screening where test indication, the purpose for which a test was performed, is often unavailable. This poses a challenge to understanding the effectiveness of screening tests because estimates of screening test effectiveness are biased if some diagnostic tests are misclassified as screening. Prediction models have been developed for a variety of exposure variables that can be derived from EHR, but no previous research has investigated appropriate methods for obtaining unbiased association estimates using these predicted probabilities. The full likelihood incorporating information on both the predicted probability of exposure-class membership and the association between the exposure and outcome of interest can be expressed using a finite mixture model. When the regression model of interest is a generalized linear model (GLM), the expectation-maximization algorithm can be used to estimate the parameters using standard software for GLMs. Using simulation studies, we compared the bias and efficiency of this mixture model approach to alternative approaches including multiple imputation and dichotomization of the predicted probabilities to create a proxy for the missing predictor. The mixture model was the only approach that was unbiased across all scenarios investigated. Finally, we explored the performance of these alternatives in a study of colorectal cancer screening with colonoscopy. These findings have broad applicability in studies using EHR data where gold-standard exposures are unavailable and prediction models have been developed for estimating proxies.
Directory of Open Access Journals (Sweden)
Matías Dewey
2017-01-01
Full Text Available This article focuses on the translation of the French and English law enforcement models into Argentina and analyzes its consequences in terms of social order. Whereas in the former two models the judiciary and police institutions originated in large-scale processes of historical consolidation, in the latter these institutions were implanted without the antecedents present in their countries of origin. The empirical references are Argentine police institutions, particularly the police of the Buenos Aires Province, observed at two moments in which the institutional import was particularly intense: towards the end of the nineteenth and beginning of the twentieth centuries, and at the end of the twentieth century. By way of tracing these processes of police constitution and reform, we show how new models of law enforcement and policing interacted with indigenous political structures and cultural frames, as well as how this constellation produced a social order in which legality and illegality are closely interwoven. The article is an attempt to go beyond the common observations regarding how an imported model failed; instead, it dissects the effects the translation actually produced and how the translated models transform into resources that reshape the new social order. A crucial element, the article shows, is that these resources can be instrumentalized according to »idiosyncrasies«, interests, and quotas of power.
Unsupervised machine learning account of magnetic transitions in the Hubbard model
Ch'ng, Kelvin; Vazquez, Nick; Khatami, Ehsan
2018-01-01
We employ several unsupervised machine learning techniques, including autoencoders, random trees embedding, and t -distributed stochastic neighboring ensemble (t -SNE), to reduce the dimensionality of, and therefore classify, raw (auxiliary) spin configurations generated, through Monte Carlo simulations of small clusters, for the Ising and Fermi-Hubbard models at finite temperatures. Results from a convolutional autoencoder for the three-dimensional Ising model can be shown to produce the magnetization and the susceptibility as a function of temperature with a high degree of accuracy. Quantum fluctuations distort this picture and prevent us from making such connections between the output of the autoencoder and physical observables for the Hubbard model. However, we are able to define an indicator based on the output of the t -SNE algorithm that shows a near perfect agreement with the antiferromagnetic structure factor of the model in two and three spatial dimensions in the weak-coupling regime. t -SNE also predicts a transition to the canted antiferromagnetic phase for the three-dimensional model when a strong magnetic field is present. We show that these techniques cannot be expected to work away from half filling when the "sign problem" in quantum Monte Carlo simulations is present.
An extension of a high temperature creep model to account for fuel sheath oxidation
International Nuclear Information System (INIS)
Boccolini, G.; Valli, G.
1983-01-01
Starting from the high-temperature creep model for Zircaloy fuel sheathing, the NIRVANA (developed by AECL), a multilayer model, is proposed in this paper: it includes the outer oxide plus alpha retained layers, and the inner core of beta or alpha plus beta material, all constrained to deform with the same creep rate. The model has been incorporated into the SPARA fuel computer code developed for the transient analysis of fuel rod behaviour in the CIRENE prototype reactor, but it is in principle valid for all Zircaloy fuel sheathings. Its predictions are compared with experimental results from burst tests on BWR and PWR type sheaths; the tests were carried out at CNEN under two research contracts with Ansaldo Meccanico Nucleare and Sigen-Sopren, respectively
Multiphysics Model of Palladium Hydride Isotope Exchange Accounting for Higher Dimensionality
Energy Technology Data Exchange (ETDEWEB)
Gharagozloo, Patricia E.; Eliassi, Mehdi; Bon, Bradley Luis
2015-03-01
This report summarizes computational model developm ent and simulations results for a series of isotope exchange dynamics experiments i ncluding long and thin isothermal beds similar to the Foltz and Melius beds and a lar ger non-isothermal experiment on the NENG7 test bed. The multiphysics 2D axi-symmetr ic model simulates the temperature and pressure dependent exchange reactio n kinetics, pressure and isotope dependent stoichiometry, heat generation from the r eaction, reacting gas flow through porous media, and non-uniformities in the bed perme ability. The new model is now able to replicate the curved reaction front and asy mmetry of the exit gas mass fractions over time. The improved understanding of the exchange process and its dependence on the non-uniform bed properties and te mperatures in these larger systems is critical to the future design of such sy stems.
DEFF Research Database (Denmark)
Gaspar, Jozsef; Ritschel, Tobias Kasper Skovborg; Jørgensen, John Bagterp
2017-01-01
-linear model based control to achieve optimal techno-economic performance. Accordingly, this work presents a computationally efficient and novel approach for solving a tray-by-tray equilibrium model and its implementation for open-loop optimal-control of a cryogenic distillation column. Here, the optimisation...... objective is to reduce the cost of compression in a volatile electricity market while meeting the production requirements, i.e. product flow rate and purity. This model is implemented in Matlab and uses the ThermoLib rigorous thermodynamic library. The present work represents a first step towards plant...
Beheshti, Rahmatollah; Jones-Smith, Jessica C; Igusa, Takeru
2017-01-01
Computational models have gained popularity as a predictive tool for assessing proposed policy changes affecting dietary choice. Specifically, they have been used for modeling dietary changes in response to economic interventions, such as price and income changes. Herein, we present a novel addition to this type of model by incorporating habitual behaviors that drive individuals to maintain or conform to prior eating patterns. We examine our method in a simulated case study of food choice behaviors of low-income adults in the US. We use data from several national datasets, including the National Health and Nutrition Examination Survey (NHANES), the US Bureau of Labor Statistics and the USDA, to parameterize our model and develop predictive capabilities in 1) quantifying the influence of prior diet preferences when food budgets are increased and 2) simulating the income elasticities of demand for four food categories. Food budgets can increase because of greater affordability (due to food aid and other nutritional assistance programs), or because of higher income. Our model predictions indicate that low-income adults consume unhealthy diets when they have highly constrained budgets, but that even after budget constraints are relaxed, these unhealthy eating behaviors are maintained. Specifically, diets in this population, before and after changes in food budgets, are characterized by relatively low consumption of fruits and vegetables and high consumption of fat. The model results for income elasticities also show almost no change in consumption of fruit and fat in response to changes in income, which is in agreement with data from the World Bank's International Comparison Program (ICP). Hence, the proposed method can be used in assessing the influences of habitual dietary patterns on the effectiveness of food policies.
Directory of Open Access Journals (Sweden)
Rahmatollah Beheshti
Full Text Available Computational models have gained popularity as a predictive tool for assessing proposed policy changes affecting dietary choice. Specifically, they have been used for modeling dietary changes in response to economic interventions, such as price and income changes. Herein, we present a novel addition to this type of model by incorporating habitual behaviors that drive individuals to maintain or conform to prior eating patterns. We examine our method in a simulated case study of food choice behaviors of low-income adults in the US. We use data from several national datasets, including the National Health and Nutrition Examination Survey (NHANES, the US Bureau of Labor Statistics and the USDA, to parameterize our model and develop predictive capabilities in 1 quantifying the influence of prior diet preferences when food budgets are increased and 2 simulating the income elasticities of demand for four food categories. Food budgets can increase because of greater affordability (due to food aid and other nutritional assistance programs, or because of higher income. Our model predictions indicate that low-income adults consume unhealthy diets when they have highly constrained budgets, but that even after budget constraints are relaxed, these unhealthy eating behaviors are maintained. Specifically, diets in this population, before and after changes in food budgets, are characterized by relatively low consumption of fruits and vegetables and high consumption of fat. The model results for income elasticities also show almost no change in consumption of fruit and fat in response to changes in income, which is in agreement with data from the World Bank's International Comparison Program (ICP. Hence, the proposed method can be used in assessing the influences of habitual dietary patterns on the effectiveness of food policies.
Improved signal model for confocal sensors accounting for object depending artifacts.
Mauch, Florian; Lyda, Wolfram; Gronle, Marc; Osten, Wolfgang
2012-08-27
The conventional signal model of confocal sensors is well established and has proven to be exceptionally robust especially when measuring rough surfaces. Its physical derivation however is explicitly based on plane surfaces or point like objects, respectively. Here we show experimental results of a confocal point sensor measurement of a surface standard. The results illustrate the rise of severe artifacts when measuring curved surfaces. On this basis, we present a systematic extension of the conventional signal model that is proven to be capable of qualitatively explaining these artifacts.
Sumarga, E.
2015-01-01
Ecosystem accounting is a new area of environmental economic accounting that aims to measure ecosystem services in a way that is in line with national accounts. The key characteristics of ecosystem accounting include the extension of the valuation boundary of the System of National Accounts, allowing the inclusion of a broader set of ecosystem services types such regulating services and cultural services. Consistent with the principles of national account, ecosystem accounting focuses on asse...
DEFF Research Database (Denmark)
de Bikuna Salinas, Koldo Saez; Hamelin, Lorie; Hauschild, Michael Zwicky
2018-01-01
Five currently used methods to account for the global warming (GW) impact of the induced land-use change (LUC) greenhouse gas (GHG) emissions have been applied to four biofuel case studies. Two of the investigated methods attempt to avoid the need of considering a definite occupation -thus...... amortization period by considering ongoing LUC trends as a dynamic baseline. This leads to the accounting of a small fraction (0.8%) of the related emissions from the assessed LUC, thus their validity is disputed. The comparison of methods and contrasting case studies illustrated the need of clearly...... distinguishing between the different time horizons involved in life cycle assessments (LCA) of land-demanding products like biofuels. Absent in ISO standards, and giving rise to several confusions, definitions for the following time horizons have been proposed: technological scope, inventory model, impact...
Bao, Yuhua; Casalino, Lawrence P; Pincus, Harold Alan
2013-01-01
Discussions of health care delivery and payment reforms have largely been silent about how behavioral health could be incorporated into reform initiatives. This paper draws attention to four patient populations defined by the severity of their behavioral health conditions and insurance status. It discusses the potentials and limitations of three prominent models promoted by the Affordable Care Act to serve populations with behavioral health conditions: the Patient-Centered Medical Home, the Health Home initiative within Medicaid, and the Accountable Care Organization. To incorporate behavioral health into health reform, policymakers and practitioners may consider embedding in the reform efforts explicit tools-accountability measures and payment designs-to improve access to and quality of care for patients with behavioral health needs.
Creative Accounting Model for Increasing Banking Industries’ Competitive Advantage in Indonesia
Directory of Open Access Journals (Sweden)
Supriyati
2015-12-01
Full Text Available Bank Indonesia demands that the national banks should improve their transparency of financial condition and performance for public in line with the development of their products and activities. Furthermore, the banks’ financial statements of Bank Indonesia have become the basis for determining the status of their soundness. In fact, they tend to practice earnings management in order that they can meet the crite-ria required by Bank Indonesia. For internal purposes, the initiative of earning management has a positive impact on the performance of management. However, for the users of financial statements, it may dif-fer, for example for the value of company, length of time the financial audit, and other aspects of tax evasion by the banks. This study tries to find out 1 the effect of GCG on Earnings Management, 2 the effect of earning management on Company value, theAudit Report Lag, and Taxation, and 3 the effect of Audit Report Lag on Corporate Value and Taxation. This is a quantitative research with the data collected from the bank financial statements, GCG implementation report, and the banks’ annual reports of 2003-2013. There were 41 banks taken using purposive sampling, as listed on the Indonesia Stock Exchange. The results showed that the implementation of GCG affects the occurrence of earning management. Accounting policy flexibility through earning management is expected to affect the length of the audit process and the accuracy of the financial statements presentation on public side. This research is expected to provide managerial implications in order to consider the possibility of earnings management practices in the banking industry. In the long term, earning management is expected to improve the banks’ competitiveness through an increase in the value of the company. Explicitly, earning management also affects the tax avoidance; therefore, the banks intend to pay lower taxes without breaking the existing legislation Taxation
Directory of Open Access Journals (Sweden)
Supriyati Supriyati
2017-01-01
Full Text Available Bank Indonesia demands that the national banks should improve their transparency of financial condition and performance for public in line with the development of their products and activities. Furthermore, the banks’ financial statements of Bank Indonesia have become the basis for determining the status of their soundness. In fact, they tend to practice earnings management in order that they can meet the criteria required by Bank Indonesia. For internal purposes, the initiative of earning management has a positive impact on the performance of management. However, for the users of financial statements, it may differ, for example for the value of company, length of time the financial audit, and other aspects of tax evasion by the banks. This study tries to find out 1 the effect of GCG on Earnings Management, 2 the effect of earning management on Company value, the Audit Report Lag, and Taxation, and 3 the effect of Audit Report Lag on Corporate Value and Taxation. This is a quantitative research with the data collected from the bank financial statements, GCG implementation report, and the banks’ annual reports of 2003-2013. There were 41 banks taken using purposive sampling, as listed on the Indonesia Stock Exchange. The results showed that the implementation of GCG affects the occurrence of earning management. Accounting policy flexibility through earning management is expected to affect the length of the audit process and the accuracy of the financial statements presentation on public side. This research is expected to provide managerial implications in order to consider the possibility of earnings management practices in the banking industry. In the long term, earning management is expected to improve the banks’ competitiveness through an increase in the value of the company. Explicitly, earning management also affects the tax avoidance; therefore, the banks intend to pay lower taxes without breaking the existing legislation Taxation
Schneider, Daniel; Schoof, Ephraim; Tschukin, Oleg; Reiter, Andreas; Herrmann, Christoph; Schwab, Felix; Selzer, Michael; Nestler, Britta
2018-03-01
Computational models based on the phase-field method have become an essential tool in material science and physics in order to investigate materials with complex microstructures. The models typically operate on a mesoscopic length scale resolving structural changes of the material and provide valuable information about the evolution of microstructures and mechanical property relations. For many interesting and important phenomena, such as martensitic phase transformation, mechanical driving forces play an important role in the evolution of microstructures. In order to investigate such physical processes, an accurate calculation of the stresses and the strain energy in the transition region is indispensable. We recall a multiphase-field elasticity model based on the force balance and the Hadamard jump condition at the interface. We show the quantitative characteristics of the model by comparing the stresses, strains and configurational forces with theoretical predictions in two-phase cases and with results from sharp interface calculations in a multiphase case. As an application, we choose the martensitic phase transformation process in multigrain systems and demonstrate the influence of the local homogenization scheme within the transition regions on the resulting microstructures.
Endrayanto, A.I.; van den Berg, Hans Leo; Boucherie, Richardus J.
2003-01-01
This paper models and analyzes downlink and uplink power assignment in Code Division Multiple Access (CDMA) mobile networks. By discretizing the area into small segments, the power requirements are characterized via a matrix representation that separates user and system characteristics. We obtain a
Working Memory Span Development: A Time-Based Resource-Sharing Model Account
Barrouillet, Pierre; Gavens, Nathalie; Vergauwe, Evie; Gaillard, Vinciane; Camos, Valerie
2009-01-01
The time-based resource-sharing model (P. Barrouillet, S. Bernardin, & V. Camos, 2004) assumes that during complex working memory span tasks, attention is frequently and surreptitiously switched from processing to reactivate decaying memory traces before their complete loss. Three experiments involving children from 5 to 14 years of age…
Accounting for false-positive acoustic detections of bats using occupancy models
Clement, Matthew J.; Rodhouse, Thomas J.; Ormsbee, Patricia C.; Szewczak, Joseph M.; Nichols, James D.
2014-01-01
1. Acoustic surveys have become a common survey method for bats and other vocal taxa. Previous work shows that bat echolocation may be misidentified, but common analytic methods, such as occupancy models, assume that misidentifications do not occur. Unless rare, such misidentifications could lead to incorrect inferences with significant management implications.
Leopold, U.; Heuvelink, G.B.M.; Tiktak, A.; Finke, P.A.; Schoumans, O.F.
2006-01-01
Agricultural activities in the Netherlands cause high nitrogen and phosphorous fluxes from soil to ground- and surface water. A model chain (STONE) has been developed to study and predict the magnitude of the resulting ground- and surface water pollution under different environmental conditions.
Rasouli, Soora; Timmermans, Harry
2014-01-01
Rasouli & Timmermans1 suggested a model of travel episode satisfaction that includes the degree and nature of multitasking, activity envelope, transport mode, travel party, duration and a set of contextual and socio-economic variables. In this sequel, the focus of attention shifts to the analysis of
Methods for Accounting for Co-Teaching in Value-Added Models. Working Paper
Hock, Heinrich; Isenberg, Eric
2012-01-01
Isolating the effect of a given teacher on student achievement (value-added modeling) is complicated when the student is taught the same subject by more than one teacher. We consider three methods, which we call the Partial Credit Method, Teacher Team Method, and Full Roster Method, for estimating teacher effects in the presence of co-teaching.…
Campo, Jochen; Wenseleers, Wim; Hales, Joel M; Makarov, Nikolay S; Perry, Joseph W
2012-08-16
A practical yet accurate dispersion model for the molecular first hyperpolarizability β is presented, incorporating both homogeneous and inhomogeneous line broadening because these affect the β dispersion differently, even if they are indistinguishable in linear absorption. Consequently, combining the absorption spectrum with one free shape-determining parameter Ginhom, the inhomogeneous line width, turns out to be necessary and sufficient to obtain a reliable description of the β dispersion, requiring no information on the homogeneous (including vibronic) and inhomogeneous line broadening mechanisms involved, providing an ideal model for practical use in extrapolating experimental nonlinear optical (NLO) data. The model is applied to the efficient NLO chromophore picolinium quinodimethane, yielding an excellent fit of the two-photon resonant wavelength-dependent data and a dependable static value β0 = 316 × 10(-30) esu. Furthermore, we show that including a second electronic excited state in the model does yield an improved description of the NLO data at shorter wavelengths but has only limited influence on β0.
Directory of Open Access Journals (Sweden)
Timothy Schilling
2006-06-01
Full Text Available In deze bijdrage wordt nagegaan in hoeverre de drie veranderkundige modellen van Donkers adequaat zijn als het gaat om de positionering van sociale interventies die zijn geïnspireerd door het geloof. Aan de hand van het werk van de Brothers of the Christians Schools in Manhattan, betoogt de auteur dat het sociaal-technologische model, het persoongeoriënteerde model en het maatschappijkritische model ontoereikend zijn om dit soort werk te plaatsen. In geen van deze modellen wordt namelijk plaats ingeruimd voor een ervaringshorizon die verder reikt dan de persoon in relatie tot de maatschappij. Terwijl voor een gelovige een horizon van de eeuwigheid of het concept van God een belangrijke rol vervult in de motivatie, het doel en het begrip van een sociale interventie. Via gebed wordt God betrokken in de relatie tussen werker en cliënt en in het veranderingsproces. De auteur stelt daarom een vierde, op het geloof gebaseerd model voor dat, zo hoopt hij, een goed interpretatiekader kan vormen voor vanuit religieuze achtergrond ingezette sociale interventies. Op die manier kan wellicht meer inzicht worden verkregen in hoe en waarom het geloof werkzaam is in de inzet voor sociale veranderingen, niet alleen het christelijk geloof, waar zijn casus betrekking op heeft, maar mogelijk ook andere religies.
Summary of model to account for inhibition of CAM corrosion by porous ceramic coating
Energy Technology Data Exchange (ETDEWEB)
Hopper, R., LLNL
1998-03-31
Corrosion occurs during five characteristic periods or regimes. These are summarized below. For more detailed discussion, see the attached Memorandum by Robert Hopper entitled `Ceramic Barrier Performance Model, Version 1.0, Description of Initial PA Input` and dated March 30, 1998.
Evaluation of alternative surface runoff accounting procedures using the SWAT model
For surface runoff estimation in the Soil and Water Assessment Tool (SWAT) model, the curve number (CN) procedure is commonly adopted to calculate surface runoff by utilizing antecedent soil moisture condition (SCSI) in field. In the recent version of SWAT (SWAT2005), an alternative approach is ava...
Endrayanto, A.I.; van den Berg, Hans Leo; Boucherie, Richardus J.
2005-01-01
This paper models and analyzes downlink and uplink power assignment in code division multiple access (CDMA) mobile networks. By discretizing the area into small segments, the power requirements are characterized via a matrix representation that separates user and system characteristics. We obtain a
Revisiting Kappa to account for change in the accuracy assessment of land-use models
Vliet, van J.; Bregt, A.K.; Hagen-Zanker, A.
2011-01-01
Land-use change models are typically calibrated to reproduce known historic changes. Calibration results can then be assessed by comparing two datasets: the simulated land-use map and the actual land-use map at the same time. A common method for this is the Kappa statistic, which expresses the
Demographic Accounting and Model-Building. Education and Development Technical Reports.
Stone, Richard
This report describes and develops a model for coordinating a variety of demographic and social statistics within a single framework. The framework proposed, together with its associated methods of analysis, serves both general and specific functions. The general aim of these functions is to give numerical definition to the pattern of society and…
Models of language: towards a practice-based account of information in natural language
Andrade-Lotero, E.J.
2012-01-01
Edgar Andrade-Lotero onderzocht twee modellen van taalkundige informatie. Hij richt zich met name op de filosofische vooronderstellingen van deze modellen. Eén van deze modellen is afkomstig uit de formele semantiek; het andere model is gebaseerd op een specifiek onderzoek naar de rol van tekens in
Frid, Leonardo; Holcombe, Tracy; Morisette, Jeffrey T.; Olsson, Aaryn D.; Brigham, Lindy; Bean, Travis M.; Betancourt, Julio L.; Bryan, Katherine
2013-01-01
Buffelgrass, a highly competitive and flammable African bunchgrass, is spreading rapidly across both urban and natural areas in the Sonoran Desert of southern and central Arizona. Damages include increased fire risk, losses in biodiversity, and diminished revenues and quality of life. Feasibility of sustained and successful mitigation will depend heavily on rates of spread, treatment capacity, and cost–benefit analysis. We created a decision support model for the wildland–urban interface north of Tucson, AZ, using a spatial state-and-transition simulation modeling framework, the Tool for Exploratory Landscape Scenario Analyses. We addressed the issues of undetected invasions, identifying potentially suitable habitat and calibrating spread rates, while answering questions about how to allocate resources among inventory, treatment, and maintenance. Inputs to the model include a state-and-transition simulation model to describe the succession and control of buffelgrass, a habitat suitability model, management planning zones, spread vectors, estimated dispersal kernels for buffelgrass, and maps of current distribution. Our spatial simulations showed that without treatment, buffelgrass infestations that started with as little as 80 ha (198 ac) could grow to more than 6,000 ha by the year 2060. In contrast, applying unlimited management resources could limit 2060 infestation levels to approximately 50 ha. The application of sufficient resources toward inventory is important because undetected patches of buffelgrass will tend to grow exponentially. In our simulations, areas affected by buffelgrass may increase substantially over the next 50 yr, but a large, upfront investment in buffelgrass control could reduce the infested area and overall management costs.
Greve, Andrea; Donaldson, David I; van Rossum, Mark C W
2010-02-01
Dual-process theories of episodic memory state that retrieval is contingent on two independent processes: familiarity (providing a sense of oldness) and recollection (recovering events and their context). A variety of studies have reported distinct neural signatures for familiarity and recollection, supporting dual-process theory. One outstanding question is whether these signatures reflect the activation of distinct memory traces or the operation of different retrieval mechanisms on a single memory trace. We present a computational model that uses a single neuronal network to store memory traces, but two distinct and independent retrieval processes access the memory. The model is capable of performing familiarity and recollection-based discrimination between old and new patterns, demonstrating that dual-process models need not to rely on multiple independent memory traces, but can use a single trace. Importantly, our putative familiarity and recollection processes exhibit distinct characteristics analogous to those found in empirical data; they diverge in capacity and sensitivity to sparse and correlated patterns, exhibit distinct ROC curves, and account for performance on both item and associative recognition tests. The demonstration that a single-trace, dual-process model can account for a range of empirical findings highlights the importance of distinguishing between neuronal processes and the neuronal representations on which they operate.
Directory of Open Access Journals (Sweden)
Koen Degeling
2017-12-01
Full Text Available Abstract Background Parametric distributions based on individual patient data can be used to represent both stochastic and parameter uncertainty. Although general guidance is available on how parameter uncertainty should be accounted for in probabilistic sensitivity analysis, there is no comprehensive guidance on reflecting parameter uncertainty in the (correlated parameters of distributions used to represent stochastic uncertainty in patient-level models. This study aims to provide this guidance by proposing appropriate methods and illustrating the impact of this uncertainty on modeling outcomes. Methods Two approaches, 1 using non-parametric bootstrapping and 2 using multivariate Normal distributions, were applied in a simulation and case study. The approaches were compared based on point-estimates and distributions of time-to-event and health economic outcomes. To assess sample size impact on the uncertainty in these outcomes, sample size was varied in the simulation study and subgroup analyses were performed for the case-study. Results Accounting for parameter uncertainty in distributions that reflect stochastic uncertainty substantially increased the uncertainty surrounding health economic outcomes, illustrated by larger confidence ellipses surrounding the cost-effectiveness point-estimates and different cost-effectiveness acceptability curves. Although both approaches performed similar for larger sample sizes (i.e. n = 500, the second approach was more sensitive to extreme values for small sample sizes (i.e. n = 25, yielding infeasible modeling outcomes. Conclusions Modelers should be aware that parameter uncertainty in distributions used to describe stochastic uncertainty needs to be reflected in probabilistic sensitivity analysis, as it could substantially impact the total amount of uncertainty surrounding health economic outcomes. If feasible, the bootstrap approach is recommended to account for this uncertainty.
Degeling, Koen; IJzerman, Maarten J; Koopman, Miriam; Koffijberg, Hendrik
2017-12-15
Parametric distributions based on individual patient data can be used to represent both stochastic and parameter uncertainty. Although general guidance is available on how parameter uncertainty should be accounted for in probabilistic sensitivity analysis, there is no comprehensive guidance on reflecting parameter uncertainty in the (correlated) parameters of distributions used to represent stochastic uncertainty in patient-level models. This study aims to provide this guidance by proposing appropriate methods and illustrating the impact of this uncertainty on modeling outcomes. Two approaches, 1) using non-parametric bootstrapping and 2) using multivariate Normal distributions, were applied in a simulation and case study. The approaches were compared based on point-estimates and distributions of time-to-event and health economic outcomes. To assess sample size impact on the uncertainty in these outcomes, sample size was varied in the simulation study and subgroup analyses were performed for the case-study. Accounting for parameter uncertainty in distributions that reflect stochastic uncertainty substantially increased the uncertainty surrounding health economic outcomes, illustrated by larger confidence ellipses surrounding the cost-effectiveness point-estimates and different cost-effectiveness acceptability curves. Although both approaches performed similar for larger sample sizes (i.e. n = 500), the second approach was more sensitive to extreme values for small sample sizes (i.e. n = 25), yielding infeasible modeling outcomes. Modelers should be aware that parameter uncertainty in distributions used to describe stochastic uncertainty needs to be reflected in probabilistic sensitivity analysis, as it could substantially impact the total amount of uncertainty surrounding health economic outcomes. If feasible, the bootstrap approach is recommended to account for this uncertainty.
International Nuclear Information System (INIS)
Hong, Kee Jeung; Kim, Jee Sang
2009-01-01
As concrete ages, the surrounding environment is expected to have growing influences on the concrete. As all the impacts of the environment cannot be considered in the strength-estimating model of a nondestructive concrete test, the increase in concrete age leads to growing uncertainty in the strength-estimating model. Therefore, the variation of the model error increases. It is necessary to include those impacts in the probability model of concrete strength attained from the nondestructive tests so as to build a more accurate reliability model for structural performance evaluation. This paper reviews and categorizes the existing strength-estimating statistical models of nondestructive concrete test, and suggests a new form of the strength-estimating statistical models to properly reflect the model uncertainty due to aging of the concrete. This new form of the statistical models will lay foundation for more accurate structural performance evaluation.
K. Di; Y. Liu; B. Liu; M. Peng
2012-01-01
Chang'E-1(CE-1) and Chang'E-2(CE-2) are the two lunar orbiters of China's lunar exploration program. Topographic mapping using CE-1 and CE-2 images is of great importance for scientific research as well as for preparation of landing and surface operation of Chang'E-3 lunar rover. In this research, we developed rigorous sensor models of CE-1 and CE-2 CCD cameras based on push-broom imaging principle with interior and exterior orientation parameters. Based on the rigorous sensor model, the 3D c...
Pringle, Abbie; Harmer, Catherine J
2015-12-01
Human models of emotional processing suggest that the direct effect of successful antidepressant drug treatment may be to modify biases in the processing of emotional information. Negative biases in emotional processing are documented in depression, and single or short-term dosing with conventional antidepressant drugs reverses these biases in depressed patients prior to any subjective change in mood. Antidepressant drug treatments also modulate emotional processing in healthy volunteers, which allows the consideration of the psychological effects of these drugs without the confound of changes in mood. As such, human models of emotional processing may prove to be useful for testing the efficacy of novel treatments and for matching treatments to individual patients or subgroups of patients.
A communication model of shared decision making: accounting for cancer treatment decisions.
Siminoff, Laura A; Step, Mary M
2005-07-01
The authors present a communication model of shared decision making (CMSDM) that explicitly identifies the communication process as the vehicle for decision making in cancer treatment. In this view, decision making is necessarily a sociocommunicative process whereby people enter into a relationship, exchange information, establish preferences, and choose a course of action. The model derives from contemporary notions of behavioral decision making and ethical conceptions of the doctor-patient relationship. This article briefly reviews the theoretical approaches to decision making, notes deficiencies, and embeds a more socially based process into the dynamics of the physician-patient relationship, focusing on cancer treatment decisions. In the CMSDM, decisions depend on (a) antecedent factors that have potential to influence communication, (b) jointly constructed communication climate, and (c) treatment preferences established by the physician and the patient.
Thevenot, Catherine; Devidal, Michel; Barrouillet, Pierre; Fayol, Michel
2007-01-01
The aim of this paper is to investigate the controversial issue of the nature of the representation constructed by individuals to solve arithmetic word problems. More precisely, we consider the relevance of two different theories: the situation or mental model theory (Johnson-Laird, 1983; Reusser, 1989) and the schema theory (Kintsch & Greeno, 1985; Riley, Greeno, & Heller, 1983). Fourth-graders who differed in their mathematical skills were presented with problems that varied in difficulty and with the question either before or after the text. We obtained the classic effect of the position of the question, with better performance when the question was presented prior to the text. In addition, this effect was more marked in the case of children who had poorer mathematical skills and in the case of more difficult problems. We argue that this pattern of results is compatible only with the situation or mental model theory, and not with the schema theory.
Refining Sunrise/set Prediction Models by Accounting for the Effects of Refraction
Wilson, Teresa; Bartlett, Jennifer L.
2016-01-01
Current atmospheric models used to predict the times of sunrise and sunset have an error of one to four minutes at mid-latitudes (0° - 55° N/S). At higher latitudes, slight changes in refraction may cause significant discrepancies, including determining even whether the Sun appears to rise or set. While different components of refraction are known, how they affect predictions of sunrise/set has not yet been quantified. A better understanding of the contributions from temperature profile, pressure, humidity, and aerosols, could significantly improve the standard prediction. Because sunrise/set times and meteorological data from multiple locations will be necessary for a thorough investigation of the problem, we will collect this data using smartphones as part of a citizen science project. This analysis will lead to more complete models that will provide more accurate times for navigators and outdoorsman alike.
Muda, Iskandar; Panjaitan, Rohdearni; Erlina; Ginting, Syafruddin; Maksum, Azhar; Abubakar
2018-03-01
The purpose of this research is to observe murabahah financing implantation model. Observations were made on one of the sharia banks going public in Indonesia. Form of implementation of such implementation in the form of financing given the exact facilities and maximum financing, then the provision of financing should be adjusted to the type, business conditions and business plans prospective mudharib. If the financing provided is too low with the mudharib requirement not reaching the target and the financing is not refundable.
International Nuclear Information System (INIS)
Mok, Chin Man; Doughty, Christine; Zhang, Keni; Pruess, Karsten; Kiureghian, Armen; Zhang, Miao; Kaback, Dawn
2010-01-01
A new computer code, CALRELTOUGH, which uses reliability methods to incorporate parameter sensitivity and uncertainty analysis into subsurface flow and transport models, was developed by Geomatrix Consultants, Inc. in collaboration with Lawrence Berkeley National Laboratory and University of California at Berkeley. The CALREL reliability code was developed at the University of California at Berkely for geotechnical applications and the TOUGH family of codes was developed at Lawrence Berkeley National Laboratory for subsurface flow and tranport applications. The integration of the two codes provides provides a new approach to deal with uncertainties in flow and transport modeling of the subsurface, such as those uncertainties associated with hydrogeology parameters, boundary conditions, and initial conditions of subsurface flow and transport using data from site characterization and monitoring for conditioning. The new code enables computation of the reliability of a system and the components that make up the system, instead of calculating the complete probability distributions of model predictions at all locations at all times. The new CALRELTOUGH code has tremendous potential to advance subsurface understanding for a variety of applications including subsurface energy storage, nuclear waste disposal, carbon sequestration, extraction of natural resources, and environmental remediation. The new code was tested on a carbon sequestration problem as part of the Phase I project. Phase iI was not awarded.
Sun, Fengxin; Wang, Jufeng; Cheng, Rongjun; Ge, Hongxia
2018-02-01
The optimal driving speeds of the different vehicles may be different for the same headway. In the optimal velocity function of the optimal velocity (OV) model, the maximum speed vmax is an important parameter determining the optimal driving speed. A vehicle with higher maximum speed is more willing to drive faster than that with lower maximum speed in similar situation. By incorporating the anticipation driving behavior of relative velocity and mixed maximum speeds of different percentages into optimal velocity function, an extended heterogeneous car-following model is presented in this paper. The analytical linear stable condition for this extended heterogeneous traffic model is obtained by using linear stability theory. Numerical simulations are carried out to explore the complex phenomenon resulted from the cooperation between anticipation driving behavior and heterogeneous maximum speeds in the optimal velocity function. The analytical and numerical results all demonstrate that strengthening driver's anticipation effect can improve the stability of heterogeneous traffic flow, and increasing the lowest value in the mixed maximum speeds will result in more instability, but increasing the value or proportion of the part already having higher maximum speed will cause different stabilities at high or low traffic densities.
Sumarga, E.
2015-01-01
Ecosystem accounting is a new area of environmental economic accounting that aims to measure ecosystem services in a way that is in line with national accounts. The key characteristics of ecosystem accounting include the extension of the valuation boundary of the System of National Accounts,
Price, B; Gomez, A; Mathys, L; Gardi, O; Schellenberger, A; Ginzler, C; Thürig, E
2017-03-01
Trees outside forest (TOF) can perform a variety of social, economic and ecological functions including carbon sequestration. However, detailed quantification of tree biomass is usually limited to forest areas. Taking advantage of structural information available from stereo aerial imagery and airborne laser scanning (ALS), this research models tree biomass using national forest inventory data and linear least-square regression and applies the model both inside and outside of forest to create a nationwide model for tree biomass (above ground and below ground). Validation of the tree biomass model against TOF data within settlement areas shows relatively low model performance (R 2 of 0.44) but still a considerable improvement on current biomass estimates used for greenhouse gas inventory and carbon accounting. We demonstrate an efficient and easily implementable approach to modelling tree biomass across a large heterogeneous nationwide area. The model offers significant opportunity for improved estimates on land use combination categories (CC) where tree biomass has either not been included or only roughly estimated until now. The ALS biomass model also offers the advantage of providing greater spatial resolution and greater within CC spatial variability compared to the current nationwide estimates.
Neiman, Tal; Loewenstein, Yonatan
2013-01-23
In free operant experiments, subjects alternate at will between targets that yield rewards stochastically. Behavior in these experiments is typically characterized by (1) an exponential distribution of stay durations, (2) matching of the relative time spent at a target to its relative share of the total number of rewards, and (3) adaptation after a change in the reward rates that can be very fast. The neural mechanism underlying these regularities is largely unknown. Moreover, current decision-making neural network models typically aim at explaining behavior in discrete-time experiments in which a single decision is made once in every trial, making these models hard to extend to the more natural case of free operant decisions. Here we show that a model based on attractor dynamics, in which transitions are induced by noise and preference is formed via covariance-based synaptic plasticity, can account for the characteristics of behavior in free operant experiments. We compare a specific instance of such a model, in which two recurrently excited populations of neurons compete for higher activity, to the behavior of rats responding on two levers for rewarding brain stimulation on a concurrent variable interval reward schedule (Gallistel et al., 2001). We show that the model is consistent with the rats' behavior, and in particular, with the observed fast adaptation to matching behavior. Further, we show that the neural model can be reduced to a behavioral model, and we use this model to deduce a novel "conservation law," which is consistent with the behavior of the rats.
Energy Technology Data Exchange (ETDEWEB)
Xavier, Roberto Salles
2014-08-01
The regimes of accountability, the organizations of global governance and institutional arrangements of global governance of nuclear non-proliferation and of Mutual Vigilance Brazilian-Argentine of Nuclear Safeguards are the subject of research. The starting point is the importance of the institutional model of global governance for the effective control of non-proliferation of nuclear weapons. In this context, the research investigates how to structure the current arrangements of the international nuclear non-proliferation and what is the performance of model Mutual Vigilance Brazilian-Argentine of Nuclear Safeguards in relation to accountability regimes of global governance. For that, was searched the current literature of three theoretical dimensions: accountability, global governance and global governance organizations. In relation to the research method was used the case study and the treatment technique of data the analysis of content. The results allowed: to establish an evaluation model based on accountability mechanisms; to assess how behaves the model Mutual Vigilance Brazilian-Argentine Nuclear Safeguards front of the proposed accountability regime; and to measure the degree to which regional arrangements that work with systems of global governance can strengthen these international systems. (author)
Energy Technology Data Exchange (ETDEWEB)
Phu, Nguyen Minh; Trinh, Nguyen Thi Minh [Vietnam National University, Ho Chi Minh City (Viet Nam)
2016-07-15
Today the helical coil heat exchanger is being employed widely due to its dominant advantages. In this study, a mathematical model was established to predict off-design works of the helical heat exchanger. The model was based on the LMTD and e-NTU methods, where a LMTD correction factor was taken into account to increase accuracy. An experimental apparatus was set-up to validate the model. Results showed that errors of thermal duty, outlet hot fluid temperature, outlet cold fluid temperature, shell-side pressure drop, and tube-side pressure drop were respectively +-5%, +-1%, +-1%, +-5% and +-2%. Diagrams of dimensionless operating parameters and a regression function were also presented as design-maps, a fast calculator for usage in design and operation of the exchanger. The study is expected to be a good tool to estimate off-design conditions of the single-phase helical heat exchangers.
Liang, Peixin; Chai, Feng; Bi, Yunlong; Pei, Yulong; Cheng, Shukang
2016-11-01
Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization.
What Time is Your Sunset? Accounting for Refraction in Sunrise/set Prediction Models
Wilson, Teresa; Bartlett, Jennifer Lynn; Chizek Frouard, Malynda; Hilton, James; Phlips, Alan; Edgar, Roman
2018-01-01
Algorithms that predict sunrise and sunset times currently have an uncertainty of one to four minutes at mid-latitudes (0° - 55° N/S) due to limitations in the atmospheric models they incorporate. At higher latitudes, slight changes in refraction can cause significant discrepancies, including difficulties determining whether the Sun appears to rise or set. While different components of refraction are known, how they affect predictions of sunrise/set has not yet been quantified. A better understanding of the contributions from temperature profile, pressure, humidity, and aerosols could significantly improve the standard prediction.We present a sunrise/set calculator that interchanges the refraction component by varying the refraction model. We, then, compared these predictions with data sets of observed rise/set times taken from Mount Wilson Observatory in California, University of Alberta in Edmonton, Alberta, and onboard the SS James Franco in the Atlantic. A thorough investigation of the problem requires a more substantial data set of observed rise/set times and corresponding meteorological data from around the world.We have developed a mobile application, Sunrise & Sunset Observer, so that anyone can capture this astronomical and meteorological data using their smartphone video recorder as part of a citizen science project. The Android app for this project is available in the Google Play store. Videos can also be submitted through the project website (riseset.phy.mtu.edu). Data analysis will lead to more complete models that will provide higher accuracy rise/set predictions to benefit astronomers, navigators, and outdoorsmen everywhere.
Optimization model of energy mix taking into account the environmental impact
International Nuclear Information System (INIS)
Gruenwald, O.; Oprea, D.
2012-01-01
At present, the energy system in the Czech Republic needs to decide some important issues regarding limited fossil resources, greater efficiency in producing of electrical energy and reducing emission levels of pollutants. These problems can be decided only by formulating and implementing an energy mix that will meet these conditions: rational, reliable, sustainable and competitive. The aim of this article is to find a new way of determining an optimal mix for the energy system in the Czech Republic. To achieve the aim, the linear optimization model comprising several economics, environmental and technical aspects will be applied. (Authors)
Making Collaborative Innovation Accountable
DEFF Research Database (Denmark)
Sørensen, Eva
The public sector is increasingly expected to be innovative, but the prize for a more innovative public sector might be that it becomes difficult to hold public authorities to account for their actions. The article explores the tensions between innovative and accountable governance, describes...... the foundation for these tensions in different accountability models, and suggest directions to take in analyzing the accountability of collaborative innovation processes....
Bailey, Larissa L.; Reid, Janice A.; Forsman, Eric D.; Nichols, James D.
2009-01-01
Barred owls (Strix varia) have recently expanded their range and now encompass the entire range of the northern spotted owl (Strix occidentalis caurina). This expansion has led to two important issues of concern for management of northern spotted owls: (1) possible competitive interactions between the two species that could contribute to population declines of northern spotted owls, and (2) possible changes in vocalization behavior and detection probabilities of northern spotted owls induced by presence of barred owls. We used a two-species occupancy model to investigate whether there was evidence of competitive exclusion between the two species at study locations in Oregon, USA. We simultaneously estimated detection probabilities for both species and determined if the presence of one species influenced the detection of the other species. Model selection results and associated parameter estimates provided no evidence that barred owls excluded spotted owls from territories. We found strong evidence that detection probabilities differed for the two species, with higher probabilities for northern spotted owls that are the object of current surveys. Non-detection of barred owls is very common in surveys for northern spotted owls, and detection of both owl species was negatively influenced by the presence of the congeneric species. Our results suggest that analyses directed at hypotheses of barred owl effects on demographic or occupancy vital rates of northern spotted owls need to deal adequately with imperfect and variable detection probabilities for both species.
Singing with yourself: evidence for an inverse modeling account of poor-pitch singing.
Pfordresher, Peter Q; Mantell, James T
2014-05-01
Singing is a ubiquitous and culturally significant activity that humans engage in from an early age. Nevertheless, some individuals - termed poor-pitch singers - are unable to match target pitches within a musical semitone while singing. In the experiments reported here, we tested whether poor-pitch singing deficits would be reduced when individuals imitate recordings of themselves as opposed to recordings of other individuals. This prediction was based on the hypothesis that poor-pitch singers have not developed an abstract "inverse model" of the auditory-vocal system and instead must rely on sensorimotor associations that they have experienced directly, which is true for sequences an individual has already produced. In three experiments, participants, both accurate and poor-pitch singers, were better able to imitate sung recordings of themselves than sung recordings of other singers. However, this self-advantage was enhanced for poor-pitch singers. These effects were not a byproduct of self-recognition (Experiment 1), vocal timbre (Experiment 2), or the absolute pitch of target recordings (i.e., the advantage remains when recordings are transposed, Experiment 3). Results support the conceptualization of poor-pitch singing as an imitative deficit resulting from a deficient inverse model of the auditory-vocal system with respect to pitch. Copyright © 2014 Elsevier Inc. All rights reserved.
Accounting emergy flows to determine the best production model of a coffee plantation
International Nuclear Information System (INIS)
Giannetti, B.F.; Ogura, Y.; Bonilla, S.H.; Almeida, C.M.V.B.
2011-01-01
Cerrado, a savannah region, is Brazil's second largest ecosystem after the Amazon rainforest and is also threatened with imminent destruction. In the present study emergy synthesis was applied to assess the environmental performance of a coffee farm located in Coromandel, Minas Gerais, in the Brazilian Cerrado. The effects of land use on sustainability were evaluated by comparing the emergy indices along ten years in order to assess the energy flows driving the production process, and to determine the best production model combining productivity and environmental performance. The emergy indices are presented as a function of the annual crop. Results show that Santo Inacio farm should produce approximately 20 bags of green coffee per hectare to accomplish its best performance regarding both the production efficiency and the environment. The evaluation of coffee trade complements those obtained by contrasting productivity and environmental performance, and despite of the market prices variation, the optimum interval for Santo Inacio's farm is between 10 and 25 coffee bags/ha. - Highlights: → Emergy synthesis is used to assess the environmental performance of a coffee farm in Brazil. → The effects of land use on sustainability were evaluated along ten years. → The energy flows driving the production process were assessed. → The best production model combining productivity and environmental performance was determined.
Accounting emergy flows to determine the best production model of a coffee plantation
Energy Technology Data Exchange (ETDEWEB)
Giannetti, B.F.; Ogura, Y.; Bonilla, S.H. [Universidade Paulista, Programa de Pos Graduacao em Engenharia de Producao, R. Dr. Bacelar, 1212 Sao Paulo SP (Brazil); Almeida, C.M.V.B., E-mail: cmvbag@terra.com.br [Universidade Paulista, Programa de Pos Graduacao em Engenharia de Producao, R. Dr. Bacelar, 1212 Sao Paulo SP (Brazil)
2011-11-15
Cerrado, a savannah region, is Brazil's second largest ecosystem after the Amazon rainforest and is also threatened with imminent destruction. In the present study emergy synthesis was applied to assess the environmental performance of a coffee farm located in Coromandel, Minas Gerais, in the Brazilian Cerrado. The effects of land use on sustainability were evaluated by comparing the emergy indices along ten years in order to assess the energy flows driving the production process, and to determine the best production model combining productivity and environmental performance. The emergy indices are presented as a function of the annual crop. Results show that Santo Inacio farm should produce approximately 20 bags of green coffee per hectare to accomplish its best performance regarding both the production efficiency and the environment. The evaluation of coffee trade complements those obtained by contrasting productivity and environmental performance, and despite of the market prices variation, the optimum interval for Santo Inacio's farm is between 10 and 25 coffee bags/ha. - Highlights: > Emergy synthesis is used to assess the environmental performance of a coffee farm in Brazil. > The effects of land use on sustainability were evaluated along ten years. > The energy flows driving the production process were assessed. > The best production model combining productivity and environmental performance was determined.
The Influence of Feedback on Task-Switching Performance: A Drift Diffusion Modeling Account
Directory of Open Access Journals (Sweden)
Russell Cohen Hoffing
2018-02-01
Full Text Available Task-switching is an important cognitive skill that facilitates our ability to choose appropriate behavior in a varied and changing environment. Task-switching training studies have sought to improve this ability by practicing switching between multiple tasks. However, an efficacious training paradigm has been difficult to develop in part due to findings that small differences in task parameters influence switching behavior in a non-trivial manner. Here, for the first time we employ the Drift Diffusion Model (DDM to understand the influence of feedback on task-switching and investigate how drift diffusion parameters change over the course of task switch training. We trained 316 participants on a simple task where they alternated sorting stimuli by color or by shape. Feedback differed in six different ways between subjects groups, ranging from No Feedback (NFB to a variety of manipulations addressing trial-wise vs. Block Feedback (BFB, rewards vs. punishments, payment bonuses and different payouts depending upon the trial type (switch/non-switch. While overall performance was found to be affected by feedback, no effect of feedback was found on task-switching learning. Drift Diffusion Modeling revealed that the reductions in reaction time (RT switch cost over the course of training were driven by a continually decreasing decision boundary. Furthermore, feedback effects on RT switch cost were also driven by differences in decision boundary, but not in drift rate. These results reveal that participants systematically modified their task-switching performance without yielding an overall gain in performance.
The Influence of Feedback on Task-Switching Performance: A Drift Diffusion Modeling Account.
Cohen Hoffing, Russell; Karvelis, Povilas; Rupprechter, Samuel; Seriès, Peggy; Seitz, Aaron R
2018-01-01
Task-switching is an important cognitive skill that facilitates our ability to choose appropriate behavior in a varied and changing environment. Task-switching training studies have sought to improve this ability by practicing switching between multiple tasks. However, an efficacious training paradigm has been difficult to develop in part due to findings that small differences in task parameters influence switching behavior in a non-trivial manner. Here, for the first time we employ the Drift Diffusion Model (DDM) to understand the influence of feedback on task-switching and investigate how drift diffusion parameters change over the course of task switch training. We trained 316 participants on a simple task where they alternated sorting stimuli by color or by shape. Feedback differed in six different ways between subjects groups, ranging from No Feedback (NFB) to a variety of manipulations addressing trial-wise vs. Block Feedback (BFB), rewards vs. punishments, payment bonuses and different payouts depending upon the trial type (switch/non-switch). While overall performance was found to be affected by feedback, no effect of feedback was found on task-switching learning. Drift Diffusion Modeling revealed that the reductions in reaction time (RT) switch cost over the course of training were driven by a continually decreasing decision boundary. Furthermore, feedback effects on RT switch cost were also driven by differences in decision boundary, but not in drift rate. These results reveal that participants systematically modified their task-switching performance without yielding an overall gain in performance.
Energy Technology Data Exchange (ETDEWEB)
Mainka, J. [Laboratorio Nacional de Computacao Cientifica (LNCC), CMC 6097, Av. Getulio Vargas 333, 25651-075 Petropolis, RJ, Caixa Postal 95113 (Brazil); Maranzana, G.; Thomas, A.; Dillet, J.; Didierjean, S.; Lottin, O. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee (LEMTA), Universite de Lorraine, 2, avenue de la Foret de Haye, 54504 Vandoeuvre-les-Nancy (France); LEMTA, CNRS, 2, avenue de la Foret de Haye, 54504 Vandoeuvre-les-Nancy (France)
2012-10-15
A one-dimensional (1D) model of oxygen transport in the diffusion media of proton exchange membrane fuel cells (PEMFC) is presented, which considers convection perpendicular to the electrode in addition to diffusion. The resulting analytical expression of the convecto-diffusive impedance is obtained using a convection-diffusion equation instead of a diffusion equation in the case of classical Warburg impedance. The main hypothesis of the model is that the convective flux is generated by the evacuation of water produced at the cathode which flows through the porous media in vapor phase. This allows the expression of the convective flux velocity as a function of the current density and of the water transport coefficient {alpha} (the fraction of water being evacuated at the cathode outlet). The resulting 1D oxygen transport impedance neglects processes occurring in the direction parallel to the electrode that could have a significant impact on the cell impedance, like gas consumption or concentration oscillations induced by the measuring signal. However, it enables us to estimate the impact of convection perpendicular to the electrode on PEMFC impedance spectra and to determine in which conditions the approximation of a purely diffusive oxygen transport is valid. Experimental observations confirm the numerical results. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Energy Technology Data Exchange (ETDEWEB)
Beckon, William N., E-mail: William_Beckon@fws.gov
2016-07-15
Highlights: • A method for estimating response time in cause-effect relationships is demonstrated. • Predictive modeling is appreciably improved by taking into account this lag time. • Bioaccumulation lag is greater for organisms at higher trophic levels. • This methodology may be widely applicable in disparate disciplines. - Abstract: For bioaccumulative substances, efforts to predict concentrations in organisms at upper trophic levels, based on measurements of environmental exposure, have been confounded by the appreciable but hitherto unknown amount of time it may take for bioaccumulation to occur through various pathways and across several trophic transfers. The study summarized here demonstrates an objective method of estimating this lag time by testing a large array of potential lag times for selenium bioaccumulation, selecting the lag that provides the best regression between environmental exposure (concentration in ambient water) and concentration in the tissue of the target organism. Bioaccumulation lag is generally greater for organisms at higher trophic levels, reaching times of more than a year in piscivorous fish. Predictive modeling of bioaccumulation is improved appreciably by taking into account this lag. More generally, the method demonstrated here may improve the accuracy of predictive modeling in a wide variety of other cause-effect relationships in which lag time is substantial but inadequately known, in disciplines as diverse as climatology (e.g., the effect of greenhouse gases on sea levels) and economics (e.g., the effects of fiscal stimulus on employment).
International Nuclear Information System (INIS)
Beckon, William N.
2016-01-01
Highlights: • A method for estimating response time in cause-effect relationships is demonstrated. • Predictive modeling is appreciably improved by taking into account this lag time. • Bioaccumulation lag is greater for organisms at higher trophic levels. • This methodology may be widely applicable in disparate disciplines. - Abstract: For bioaccumulative substances, efforts to predict concentrations in organisms at upper trophic levels, based on measurements of environmental exposure, have been confounded by the appreciable but hitherto unknown amount of time it may take for bioaccumulation to occur through various pathways and across several trophic transfers. The study summarized here demonstrates an objective method of estimating this lag time by testing a large array of potential lag times for selenium bioaccumulation, selecting the lag that provides the best regression between environmental exposure (concentration in ambient water) and concentration in the tissue of the target organism. Bioaccumulation lag is generally greater for organisms at higher trophic levels, reaching times of more than a year in piscivorous fish. Predictive modeling of bioaccumulation is improved appreciably by taking into account this lag. More generally, the method demonstrated here may improve the accuracy of predictive modeling in a wide variety of other cause-effect relationships in which lag time is substantial but inadequately known, in disciplines as diverse as climatology (e.g., the effect of greenhouse gases on sea levels) and economics (e.g., the effects of fiscal stimulus on employment).
Cooper, Rachel
2017-08-01
In this article, I compare and evaluate R. D. Laing and A. Esterson's account of schizophrenia as developed in Sanity, Madness and the Family (1964), social models of disability, and accounts of extended mental disorder. These accounts claim that some putative disorders (schizophrenia, disability, certain mental disorders) should not be thought of as reflecting biological or psychological dysfunction within the afflicted individual, but instead as external problems (to be located in the family, or in the material and social environment). In this article, I consider the grounds on which such claims might be supported. I argue that problems should not be located within an individual putative patient in cases where there is some acceptable test environment in which there is no problem. A number of cases where such an argument can show that there is no internal disorder are discussed. I argue, however, that Laing and Esterson's argument-that schizophrenia is not within diagnosed patients-does not work. The problem with their argument is that they fail to show that the diagnosed women in their study function adequately in any environment.
International Nuclear Information System (INIS)
Perfetti, E.
2006-11-01
Modelling fluid-rock interactions as well as mixing and unmixing phenomena in geological processes requires robust equations of state (EOS) which must be applicable to systems containing water, gases over a broad range of temperatures and pressures. Cubic equations of state based on the Van der Waals theory (e. g. Soave-Redlich-Kwong or Peng-Robinson) allow simple modelling from the critical parameters of the studied fluid components. However, the accuracy of such equations becomes poor when water is a major component of the fluid since neither association trough hydrogen bonding nor dipolar interactions are accounted for. The Helmholtz energy of a fluid may be written as the sum of different energetic contributions by factorization of partition function. The model developed in this thesis for the pure H 2 O and H 2 S considers three contributions. The first contribution represents the reference Van der Waals fluid which is modelled by the SRK cubic EOS. The second contribution accounts for association through hydrogen bonding and is modelled by a term derived from Cubic Plus Association (CPA) theory. The third contribution corresponds to the dipolar interactions and is modelled by the Mean Spherical Approximation (MSA) theory. The resulting CPAMSA equation has six adjustable parameters, which three represent physical terms whose values are close to their experimental counterpart. This equation results in a better reproduction of the thermodynamic properties of pure water than obtained using the classical CPA equation along the vapour-liquid equilibrium. In addition, extrapolation to higher temperatures and pressure is satisfactory. Similarly, taking into account dipolar interactions together with the SRK cubic equation of state for calculating molar volume of H 2 S as a function of pressure and temperature results in a significant improvement compared to the SRK equation alone. Simple mixing rules between dipolar molecules are proposed to model the H 2 O-H 2 S
International Nuclear Information System (INIS)
Pérez-Sánchez, D.; Thorne, M.C.
2014-01-01
In a previous paper, a mathematical model for the behaviour of 79 Se in soils and plants was described. Subsequently, a review has been published relating to the behaviour of 238 U-series radionuclides in soils and plants. Here, we bring together those two strands of work to describe a new mathematical model of the behaviour of 238 U-series radionuclides entering soils in solution and their uptake by plants. Initial studies with the model that are reported here demonstrate that it is a powerful tool for exploring the behaviour of this decay chain or subcomponents of it in soil-plant systems under different hydrological regimes. In particular, it permits studies of the degree to which secular equilibrium assumptions are appropriate when modelling this decay chain. Further studies will be undertaken and reported separately examining sensitivities of model results to input parameter values and also applying the model to sites contaminated with 238 U-series radionuclides. - Highlights: • Kinetic model of radionuclide transport in soils and uptake by plants. • Takes soil hydrology and redox conditions into account. • Applicable to the whole U-238 chain, including Rn-222, Pb-210 and Po-210. • Demonstrates intra-season and inter-season variability on timescales up to thousands of years
International Nuclear Information System (INIS)
Dorokhov, A.E.; Kanokov, Z.; Musakhanov, M.M.; Rakhimov, A.M.
1989-01-01
Pion production on a nucleon is studied in the chiral bag model (CBM). A CBM version is investigated in which the pions get into the bag and interact with quarks in a pseudovector way in the entire volume. Charged pion photoproduction amplitudes are found taking into account the recoil nucleon motion effects. Angular and energy distributions of charged pions, polarization of the recoil nucleon, multipoles are calculated. The recoil effects are shon to give an additional contribution to the static approximation of order of 10-20%. At bag radius value R=1 in the calculations are consistent with the experimental data
DEFF Research Database (Denmark)
Johannesson, Björn; Janz, Mårten
2009-01-01
Building constructions most commonly consists of layered porous materials such as masonry on bricks. The moisture distribution and its variations due to change in surrounding environment is of special interest in such layered construction since materials adsorb different amounts of water and exhi......Building constructions most commonly consists of layered porous materials such as masonry on bricks. The moisture distribution and its variations due to change in surrounding environment is of special interest in such layered construction since materials adsorb different amounts of water....... The model is developed by carefully examining the mass balance postulates for the two considered constituents together with appropriate and suitable constitutive assumptions. A test example is solved by using an implemented implicit finite element code which uses a modified Newton-Raphson scheme to tackle...
Simple model for taking into account the effects of plasma screening in thermonuclear reactions
International Nuclear Information System (INIS)
Shalybkov, D.A.; Yakovlev, D.G.
1988-01-01
In the Thomas-Fermi model of high-density matter analytic calculation is made of the factor by which the rate of the thermonuclear reactions is enhanced by the effects of plasma screening in a degenerate weakly non-ideal electron gas and a strongly nonideal two-component ion liquid with large charge of the ions. The regions of densities and temperatures in which screening due to compressibility of the electron gas plays an important part are found. It is noted that the screening due to this compressibility may be influenced by strong magnetic fields B /approximately/ 10 12 -10 13 G, which quantize the motion of the electrons and change the electron charge screening length in the plasma. The results can be used for the degenerate cores of white dwarfs and shells of neutron stars
Model of investment appraisal of high-rise construction with account of cost of land resources
Okolelova, Ella; Shibaeva, Marina; Trukhina, Natalya
2018-03-01
The article considers problems and potential of high-rise construction as a global urbanization. The results of theoretical and practical studies on the appraisal of investments in high-rise construction are provided. High-rise construction has a number of apparent upsides in modern terms of development of megapolises and primarily it is economically efficient. Amid serious lack of construction sites, skyscrapers successfully deal with the need of manufacturing, office and living premises. Nevertheless, there are plenty issues, which are related with high-rise construction, and only thorough scrutiny of them allow to estimate the real economic efficiency of this branch. The article focuses on the question of economic efficiency of high-rise construction. The suggested model allows adjusting the parameters of a facility under construction, setting the tone for market value as well as the coefficient for appreciation of the construction net cost, that depends on the number of storey's, in the form of function or discrete values.
Peridynamics as a rigorous coarse-graining of atomistics for multiscale materials design
International Nuclear Information System (INIS)
Lehoucq, Richard B.; Aidun, John Bahram; Silling, Stewart Andrew; Sears, Mark P.; Kamm, James R.; Parks, Michael L.
2010-01-01
This report summarizes activities undertaken during FY08-FY10 for the LDRD Peridynamics as a Rigorous Coarse-Graining of Atomistics for Multiscale Materials Design. The goal of our project was to develop a coarse-graining of finite temperature molecular dynamics (MD) that successfully transitions from statistical mechanics to continuum mechanics. The goal of our project is to develop a coarse-graining of finite temperature molecular dynamics (MD) that successfully transitions from statistical mechanics to continuum mechanics. Our coarse-graining overcomes the intrinsic limitation of coupling atomistics with classical continuum mechanics via the FEM (finite element method), SPH (smoothed particle hydrodynamics), or MPM (material point method); namely, that classical continuum mechanics assumes a local force interaction that is incompatible with the nonlocal force model of atomistic methods. Therefore FEM, SPH, and MPM inherit this limitation. This seemingly innocuous dichotomy has far reaching consequences; for example, classical continuum mechanics cannot resolve the short wavelength behavior associated with atomistics. Other consequences include spurious forces, invalid phonon dispersion relationships, and irreconcilable descriptions/treatments of temperature. We propose a statistically based coarse-graining of atomistics via peridynamics and so develop a first of a kind mesoscopic capability to enable consistent, thermodynamically sound, atomistic-to-continuum (AtC) multiscale material simulation. Peridynamics (PD) is a microcontinuum theory that assumes nonlocal forces for describing long-range material interaction. The force interactions occurring at finite distances are naturally accounted for in PD. Moreover, PDs nonlocal force model is entirely consistent with those used by atomistics methods, in stark contrast to classical continuum mechanics. Hence, PD can be employed for mesoscopic phenomena that are beyond the realms of classical continuum mechanics and
Pore Network Modeling: Alternative Methods to Account for Trapping and Spatial Correlation
De La Garza Martinez, Pablo
2016-05-01
Pore network models have served as a predictive tool for soil and rock properties with a broad range of applications, particularly in oil recovery, geothermal energy from underground reservoirs, and pollutant transport in soils and aquifers [39]. They rely on the representation of the void space within porous materials as a network of interconnected pores with idealised geometries. Typically, a two-phase flow simulation of a drainage (or imbibition) process is employed, and by averaging the physical properties at the pore scale, macroscopic parameters such as capillary pressure and relative permeability can be estimated. One of the most demanding tasks in these models is to include the possibility of fluids to remain trapped inside the pore space. In this work I proposed a trapping rule which uses the information of neighboring pores instead of a search algorithm. This approximation reduces the simulation time significantly and does not perturb the accuracy of results. Additionally, I included spatial correlation to generate the pore sizes using a matrix decomposition method. Results show higher relative permeabilities and smaller values for irreducible saturation, which emphasizes the effects of ignoring the intrinsic correlation seen in pore sizes from actual porous media. Finally, I implemented the algorithm from Raoof et al. (2010) [38] to generate the topology of a Fontainebleau sandstone by solving an optimization problem using the steepest descent algorithm with a stochastic approximation for the gradient. A drainage simulation is performed on this representative network and relative permeability is compared with published results. The limitations of this algorithm are discussed and other methods are suggested to create a more faithful representation of the pore space.
Pore Network Modeling: Alternative Methods to Account for Trapping and Spatial Correlation
De La Garza Martinez, Pablo
2016-01-01
Pore network models have served as a predictive tool for soil and rock properties with a broad range of applications, particularly in oil recovery, geothermal energy from underground reservoirs, and pollutant transport in soils and aquifers [39]. They rely on the representation of the void space within porous materials as a network of interconnected pores with idealised geometries. Typically, a two-phase flow simulation of a drainage (or imbibition) process is employed, and by averaging the physical properties at the pore scale, macroscopic parameters such as capillary pressure and relative permeability can be estimated. One of the most demanding tasks in these models is to include the possibility of fluids to remain trapped inside the pore space. In this work I proposed a trapping rule which uses the information of neighboring pores instead of a search algorithm. This approximation reduces the simulation time significantly and does not perturb the accuracy of results. Additionally, I included spatial correlation to generate the pore sizes using a matrix decomposition method. Results show higher relative permeabilities and smaller values for irreducible saturation, which emphasizes the effects of ignoring the intrinsic correlation seen in pore sizes from actual porous media. Finally, I implemented the algorithm from Raoof et al. (2010) [38] to generate the topology of a Fontainebleau sandstone by solving an optimization problem using the steepest descent algorithm with a stochastic approximation for the gradient. A drainage simulation is performed on this representative network and relative permeability is compared with published results. The limitations of this algorithm are discussed and other methods are suggested to create a more faithful representation of the pore space.
Carenzo, Marco; Mabillard, Johan; Pellicciotti, Francesca; Reid, Tim; Brock, Ben; Burlando, Paolo
2013-04-01
The increase of rockfalls from the surrounding slopes and of englacial melt-out material has led to an increase of the debris cover extent on Alpine glaciers. In recent years, distributed debris energy-balance models have been developed to account for the melt rate enhancing/reduction due to a thin/thick debris layer, respectively. However, such models require a large amount of input data that are not often available, especially in remote mountain areas such as the Himalaya. Some of the input data such as wind or temperature are also of difficult extrapolation from station measurements. Due to their lower data requirement, empirical models have been used in glacier melt modelling. However, they generally simplify the debris effect by using a single melt-reduction factor which does not account for the influence of debris thickness on melt. In this paper, we present a new temperature-index model accounting for the debris thickness feedback in the computation of melt rates at the debris-ice interface. The empirical parameters (temperature factor, shortwave radiation factor, and lag factor accounting for the energy transfer through the debris layer) are optimized at the point scale for several debris thicknesses against melt rates simulated by a physically-based debris energy balance model. The latter has been validated against ablation stake readings and surface temperature measurements. Each parameter is then related to a plausible set of debris thickness values to provide a general and transferable parameterization. The new model is developed on Miage Glacier, Italy, a debris cover glacier in which the ablation area is mantled in near-continuous layer of rock. Subsequently, its transferability is tested on Haut Glacier d'Arolla, Switzerland, where debris is thinner and its extension has been seen to expand in the last decades. The results show that the performance of the new debris temperature-index model (DETI) in simulating the glacier melt rate at the point scale
New rigorous asymptotic theorems for inverse scattering amplitudes
International Nuclear Information System (INIS)
Lomsadze, Sh.Yu.; Lomsadze, Yu.M.
1984-01-01
The rigorous asymptotic theorems both of integral and local types obtained earlier and establishing logarithmic and in some cases even power correlations aetdeen the real and imaginary parts of scattering amplitudes Fsub(+-) are extended to the inverse amplitudes 1/Fsub(+-). One also succeeds in establishing power correlations of a new type between the real and imaginary parts, both for the amplitudes themselves and for the inverse ones. All the obtained assertions are convenient to be tested in high energy experiments when the amplitudes show asymptotic behaviour
Hanan, Erin J; Tague, Christina; Choate, Janet; Liu, Mingliang; Kolden, Crystal; Adam, Jennifer
2018-03-24
Disturbances such as wildfire, insect outbreaks, and forest clearing, play an important role in regulating carbon, nitrogen, and hydrologic fluxes in terrestrial watersheds. Evaluating how watersheds respond to disturbance requires understanding mechanisms that interact over multiple spatial and temporal scales. Simulation modeling is a powerful tool for bridging these scales; however, model projections are limited by uncertainties in the initial state of plant carbon and nitrogen stores. Watershed models typically use one of two methods to initialize these stores: spin-up to steady state or remote sensing with allometric relationships. Spin-up involves running a model until vegetation reaches equilibrium based on climate. This approach assumes that vegetation across the watershed has reached maturity and is of uniform age, which fails to account for landscape heterogeneity and non-steady-state conditions. By contrast, remote sensing, can provide data for initializing such conditions. However, methods for assimilating remote sensing into model simulations can also be problematic. They often rely on empirical allometric relationships between a single vegetation variable and modeled carbon and nitrogen stores. Because allometric relationships are species- and region-specific, they do not account for the effects of local resource limitation, which can influence carbon allocation (to leaves, stems, roots, etc.). To address this problem, we developed a new initialization approach using the catchment-scale ecohydrologic model RHESSys. The new approach merges the mechanistic stability of spin-up with the spatial fidelity of remote sensing. It uses remote sensing to define spatially explicit targets for one or several vegetation state variables, such as leaf area index, across a watershed. The model then simulates the growth of carbon and nitrogen stores until the defined targets are met for all locations. We evaluated this approach in a mixed pine-dominated watershed in
Modelling of a mecanum wheel taking into account the geometry of road rollers
Hryniewicz, P.; Gwiazda, A.; Banaś, W.; Sękala, A.; Foit, K.
2017-08-01
During the process planning in a company one of the basic factors associated with the production costs is the operation time for particular technological jobs. The operation time consists of time units associated with the machining tasks of a workpiece as well as the time associated with loading and unloading and the transport operations of this workpiece between machining stands. Full automation of manufacturing in industry companies tends to a maximal reduction in machine downtimes, thereby the fixed costs simultaneously decreasing. The new construction of wheeled vehicles, using Mecanum wheels, reduces the transport time of materials and workpieces between machining stands. These vehicles have the ability to simultaneously move in two axes and thus more rapid positioning of the vehicle relative to the machining stand. The Mecanum wheel construction implies placing, around the wheel free rollers that are mounted at an angle 450, which allow the movement of the vehicle not only in its axis but also perpendicular thereto. The improper selection of the rollers can cause unwanted vertical movement of the vehicle, which may cause difficulty in positioning of the vehicle in relation to the machining stand and the need for stabilisation. Hence the proper design of the free rollers is essential in designing the whole Mecanum wheel construction. It allows avoiding the disadvantageous and unwanted vertical vibrations of a whole vehicle with these wheels. In the article the process of modelling the free rollers, in order to obtain the desired shape of unchanging, horizontal trajectory of the vehicle is presented. This shape depends on the desired diameter of the whole Mecanum wheel, together with the road rollers, and the width of the drive wheel. Another factor related with the curvature of the trajectory shape is the length of the road roller and its diameter decreases depending on the position with respect to its centre. The additional factor, limiting construction of
Gonçalves, M A D; Bello, N M; Dritz, S S; Tokach, M D; DeRouchey, J M; Woodworth, J C; Goodband, R D
2016-05-01
Advanced methods for dose-response assessments are used to estimate the minimum concentrations of a nutrient that maximizes a given outcome of interest, thereby determining nutritional requirements for optimal performance. Contrary to standard modeling assumptions, experimental data often present a design structure that includes correlations between observations (i.e., blocking, nesting, etc.) as well as heterogeneity of error variances; either can mislead inference if disregarded. Our objective is to demonstrate practical implementation of linear and nonlinear mixed models for dose-response relationships accounting for correlated data structure and heterogeneous error variances. To illustrate, we modeled data from a randomized complete block design study to evaluate the standardized ileal digestible (SID) Trp:Lys ratio dose-response on G:F of nursery pigs. A base linear mixed model was fitted to explore the functional form of G:F relative to Trp:Lys ratios and assess model assumptions. Next, we fitted 3 competing dose-response mixed models to G:F, namely a quadratic polynomial (QP) model, a broken-line linear (BLL) ascending model, and a broken-line quadratic (BLQ) ascending model, all of which included heteroskedastic specifications, as dictated by the base model. The GLIMMIX procedure of SAS (version 9.4) was used to fit the base and QP models and the NLMIXED procedure was used to fit the BLL and BLQ models. We further illustrated the use of a grid search of initial parameter values to facilitate convergence and parameter estimation in nonlinear mixed models. Fit between competing dose-response models was compared using a maximum likelihood-based Bayesian information criterion (BIC). The QP, BLL, and BLQ models fitted on G:F of nursery pigs yielded BIC values of 353.7, 343.4, and 345.2, respectively, thus indicating a better fit of the BLL model. The BLL breakpoint estimate of the SID Trp:Lys ratio was 16.5% (95% confidence interval [16.1, 17.0]). Problems with
DEFF Research Database (Denmark)
Löwe, Roland; Del Giudice, Dario; Mikkelsen, Peter Steen
of input uncertainties observed in the models. The explicit inclusion of such variations in the modelling process will lead to a better fulfilment of the assumptions made in formal statistical frameworks, thus reducing the need to resolve to informal methods. The two approaches presented here...
Loersch, Chris; Payne, B Keith
2011-05-01
The downstream consequences of a priming induction range from changes in the perception of objects in the environment to the initiation of prime-related behavior and goal striving. Although each of these outcomes has been accounted for by separate mechanisms, we argue that a single process could produce all three priming effects. In this article, we introduce the situated inference model of priming, discuss its potential to account for these divergent outcomes with one mechanism, and demonstrate its ability to organize the priming literatures surrounding these effects. According to the model, primes often do not cause direct effects, instead altering only the accessibility of prime-related mental content. This information produces downstream effects on judgment, behavior, or motivation when it is mistakenly viewed as originating from one's own internal thought processes. When this misattribution occurs, the prime-related mental content becomes a possible source of information for solving whatever problems are afforded by the current situation. Because different situations afford very different questions and concerns, the inferred meaning of this prime-related content can vary greatly. The use of this information to answer qualitatively different questions can lead a single prime to produce varied effects on judgment, behavior, and motivation. © The Author(s) 2011.
Kling, Daniel; Tillmar, Andreas; Egeland, Thore; Mostad, Petter
2015-09-01
Several applications necessitate an unbiased determination of relatedness, be it in linkage or association studies or in a forensic setting. An appropriate model to compute the joint probability of some genetic data for a set of persons given some hypothesis about the pedigree structure is then required. The increasing number of markers available through high-density SNP microarray typing and NGS technologies intensifies the demand, where using a large number of markers may lead to biased results due to strong dependencies between closely located loci, both within pedigrees (linkage) and in the population (allelic association or linkage disequilibrium (LD)). We present a new general model, based on a Markov chain for inheritance patterns and another Markov chain for founder allele patterns, the latter allowing us to account for LD. We also demonstrate a specific implementation for X chromosomal markers that allows for computation of likelihoods based on hypotheses of alleged relationships and genetic marker data. The algorithm can simultaneously account for linkage, LD, and mutations. We demonstrate its feasibility using simulated examples. The algorithm is implemented in the software FamLinkX, providing a user-friendly GUI for Windows systems (FamLinkX, as well as further usage instructions, is freely available at www.famlink.se ). Our software provides the necessary means to solve cases where no previous implementation exists. In addition, the software has the possibility to perform simulations in order to further study the impact of linkage and LD on computed likelihoods for an arbitrary set of markers.
Sonoelasticity to monitor mechanical changes during rigor and ageing.
Ayadi, A; Culioli, J; Abouelkaram, S
2007-06-01
We propose the use of sonoelasticity as a non-destructive method to monitor changes in the resistance of muscle fibres, unaffected by connective tissue. Vibrations were applied at low frequency to induce oscillations in soft tissues and an ultrasound transducer was used to detect the motions. The experiments were carried out on the M. biceps femoris muscles of three beef cattle. In addition to the sonoelasticity measurements, the changes in meat during rigor and ageing were followed by measurements of both the mechanical resistance of myofibres and pH. The variations of mechanical resistance and pH were compared to those of the sonoelastic variables (velocity and attenuation) at two frequencies. The relationships between pH and velocity or attenuation and between the velocity or attenuation and the stress at 20% deformation were highly correlated. We concluded that sonoelasticity is a non-destructive method that can be used to monitor mechanical changes in muscle fibers during rigor-mortis and ageing.
Rigorous quantum limits on monitoring free masses and harmonic oscillators
Roy, S. M.
2018-03-01
There are heuristic arguments proposing that the accuracy of monitoring position of a free mass m is limited by the standard quantum limit (SQL): σ2( X (t ) ) ≥σ2( X (0 ) ) +(t2/m2) σ2( P (0 ) ) ≥ℏ t /m , where σ2( X (t ) ) and σ2( P (t ) ) denote variances of the Heisenberg representation position and momentum operators. Yuen [Phys. Rev. Lett. 51, 719 (1983), 10.1103/PhysRevLett.51.719] discovered that there are contractive states for which this result is incorrect. Here I prove universally valid rigorous quantum limits (RQL), viz. rigorous upper and lower bounds on σ2( X (t ) ) in terms of σ2( X (0 ) ) and σ2( P (0 ) ) , given by Eq. (12) for a free mass and by Eq. (36) for an oscillator. I also obtain the maximally contractive and maximally expanding states which saturate the RQL, and use the contractive states to set up an Ozawa-type measurement theory with accuracies respecting the RQL but beating the standard quantum limit. The contractive states for oscillators improve on the Schrödinger coherent states of constant variance and may be useful for gravitational wave detection and optical communication.
Krompecher, Thomas; Gilles, André; Brandt-Casadevall, Conception; Mangin, Patrice
2008-04-07
Objective measurements were carried out to study the possible re-establishment of rigor mortis on rats after "breaking" (mechanical solution). Our experiments showed that: *Cadaveric rigidity can re-establish after breaking. *A significant rigidity can reappear if the breaking occurs before the process is complete. *Rigidity will be considerably weaker after the breaking. *The time course of the intensity does not change in comparison to the controls: --the re-establishment begins immediately after the breaking; --maximal values are reached at the same time as in the controls; --the course of the resolution is the same as in the controls.
International Nuclear Information System (INIS)
Avenhaus, R.; Spannagel, G.
1995-01-01
Conventional accountancy means that for a given material balance area and a given interval of time the tritium balance is established so that at the end of that interval of time the book inventory is compared with the measured inventory. In this way, an optimal effectiveness of accountancy is achieved. However, there are still further objectives of accountancy, namely the timely detection of anomalies as well as the localization of anomalies in a major system. It can be shown that each of these objectives can be optimized only at the expense of the others. Recently, Near-Real-Time Accountancy procedures have been studied; their methodological background as well as their merits will be discussed. (orig.)
Directory of Open Access Journals (Sweden)
V. V. Knyazkov
2014-01-01
Full Text Available To evaluate the force to damage the ice covers is necessary for estimation of icebreaking capability of vessels, as well as of hull strength of icebreakers, and navigation of ships in ice conditions. On the other hand, the use of ice cover support to arrange construction works from the ice is also of practical interest.By the present moment a great deal of investigations of ice cover deformation have been carried out to result, usually, in approximate calculations formula which was obtained after making a variety of assumptions. Nevertheless, we believe that it is possible to make further improvement in calculations. Application numerical methods, and, for example, FEM, makes possible to avoid numerous drawbacks of analytical methods dealing with both complex boundaries and load application areas and other problem peculiarities.The article considers an application of mixed models of FEM for investigating ice cover deformation. A simple flexible triangle element of mixed type was taken to solve this problem. Vector of generalized coordinates of the element contains apices flexures and normal bending moments in the middle of its sides. Compared to other elements mixed models easily satisfy compatibility requirements on the boundary of adjacent elements and do not require numerical displacement differentiation to define bending moments, because bending moments are included in vector of element generalized coordinates.The method of account of rigid support plate is proposed. The resulting ratio, taking into account the "stiffening", reduces the number of resolving systems of equations by the number of elements on the plate contour.To evaluate further the results the numerical realization of ice cover stress-strained problem it becomes necessary and correct to check whether calculation results correspond to accurate solution. Using an example of circular plate the convergence of numerical solutions to analytical solutions is showed.The article
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Vadas Gintautas
2011-10-01
Full Text Available Can lateral connectivity in the primary visual cortex account for the time dependence and intrinsic task difficulty of human contour detection? To answer this question, we created a synthetic image set that prevents sole reliance on either low-level visual features or high-level context for the detection of target objects. Rendered images consist of smoothly varying, globally aligned contour fragments (amoebas distributed among groups of randomly rotated fragments (clutter. The time course and accuracy of amoeba detection by humans was measured using a two-alternative forced choice protocol with self-reported confidence and variable image presentation time (20-200 ms, followed by an image mask optimized so as to interrupt visual processing. Measured psychometric functions were well fit by sigmoidal functions with exponential time constants of 30-91 ms, depending on amoeba complexity. Key aspects of the psychophysical experiments were accounted for by a computational network model, in which simulated responses across retinotopic arrays of orientation-selective elements were modulated by cortical association fields, represented as multiplicative kernels computed from the differences in pairwise edge statistics between target and distractor images. Comparing the experimental and the computational results suggests that each iteration of the lateral interactions takes at least [Formula: see text] ms of cortical processing time. Our results provide evidence that cortical association fields between orientation selective elements in early visual areas can account for important temporal and task-dependent aspects of the psychometric curves characterizing human contour perception, with the remaining discrepancies postulated to arise from the influence of higher cortical areas.
Directory of Open Access Journals (Sweden)
Luminita Rus
2014-07-01
Full Text Available Nowadays it is vital to stay informed. But why is the information so important? The following will present the role and the importance of accounting information in decision-making regarding economic entity. Is accounting information a want or a need? Can accounting information be interpreted correctly indifferent of the accounting model used? Decisions made by the consumers of accounting information would be the same in terms of using the "cash" or "accrual" method? Based on these questions, this paper presents data as a whole for everyone and from where each consumer of information can extract only the part that they are interested in and which is useful for them. This paper follows the interests of users of accounting information regarding the interest, the need for information and the decisions they may take as a result of the information received, and also of the accounting model used by the entity from which the information is expected. This paper does not include all users of the accounting information that have interest in the economic entity, nor does it take into account all the information that are affected by the use of a model of accounting or the other one of the economic entity, but we can conclude that there are situations in which users ' decisions are influenced by the accounting model used, and others where there is no influence. We can't rule on any model to be the best; it is good that provides useful information showing the true reality of the economic entity.
Directory of Open Access Journals (Sweden)
Kafka S.М.
2017-03-01
Full Text Available The proper evaluation of accounting objects influences essentially upon the reliability of assessing the financial situation of a company. Thus, the problem in accounting estimate is quite relevant. The works of home and foreign scholars on the issues of assessment of accounting objects, regulatory and legal acts of Ukraine controlling the accounting and compiling financial reporting are a methodological basis for the research. The author uses the theoretical methods of cognition (abstraction and generalization, analysis and synthesis, induction and deduction and other methods producing conceptual knowledge for the synthesis of theoretical and methodological principles in the evaluation of assets accounting, liabilities and equity. The tabular presentation and information comparison methods are used for analytical researches. The article considers the modern approaches to the issue of evaluation of accounting objects and financial statements items. The expedience to keep records under historical value is proved and the articles of financial statements are to be presented according to the evaluation on the reporting date. In connection with the evaluation the depreciation of fixed assets is considered as a process of systematic return into circulation of the before advanced funds on the purchase (production, improvement of fixed assets and intangible assets by means of including the amount of wear in production costs. Therefore it is proposed to amortize only the actual costs incurred, i.e. not to depreciate the fixed assets received free of charge and surplus valuation of different kinds.
Shen, Chung-Wei; Chen, Yi-Hau
2018-03-13
We propose a model selection criterion for semiparametric marginal mean regression based on generalized estimating equations. The work is motivated by a longitudinal study on the physical frailty outcome in the elderly, where the cluster size, that is, the number of the observed outcomes in each subject, is "informative" in the sense that it is related to the frailty outcome itself. The new proposal, called Resampling Cluster Information Criterion (RCIC), is based on the resampling idea utilized in the within-cluster resampling method (Hoffman, Sen, and Weinberg, 2001, Biometrika 88, 1121-1134) and accommodates informative cluster size. The implementation of RCIC, however, is free of performing actual resampling of the data and hence is computationally convenient. Compared with the existing model selection methods for marginal mean regression, the RCIC method incorporates an additional component accounting for variability of the model over within-cluster subsampling, and leads to remarkable improvements in selecting the correct model, regardless of whether the cluster size is informative or not. Applying the RCIC method to the longitudinal frailty study, we identify being female, old age, low income and life satisfaction, and chronic health conditions as significant risk factors for physical frailty in the elderly. © 2018, The International Biometric Society.
Edouard, Simon; Vincendon, Béatrice; Ducrocq, Véronique
2018-05-01
Intense precipitation events in the Mediterranean often lead to devastating flash floods (FF). FF modelling is affected by several kinds of uncertainties and Hydrological Ensemble Prediction Systems (HEPS) are designed to take those uncertainties into account. The major source of uncertainty comes from rainfall forcing and convective-scale meteorological ensemble prediction systems can manage it for forecasting purpose. But other sources are related to the hydrological modelling part of the HEPS. This study focuses on the uncertainties arising from the hydrological model parameters and initial soil moisture with aim to design an ensemble-based version of an hydrological model dedicated to Mediterranean fast responding rivers simulations, the ISBA-TOP coupled system. The first step consists in identifying the parameters that have the strongest influence on FF simulations by assuming perfect precipitation. A sensitivity study is carried out first using a synthetic framework and then for several real events and several catchments. Perturbation methods varying the most sensitive parameters as well as initial soil moisture allow designing an ensemble-based version of ISBA-TOP. The first results of this system on some real events are presented. The direct perspective of this work will be to drive this ensemble-based version with the members of a convective-scale meteorological ensemble prediction system to design a complete HEPS for FF forecasting.
Energy Technology Data Exchange (ETDEWEB)
Liang, Peixin; Chai, Feng [State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001 (China); Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Bi, Yunlong [Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Pei, Yulong, E-mail: peiyulong1@163.com [Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Cheng, Shukang [State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001 (China); Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China)
2016-11-01
Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization. - Highlights: • The no-load magnetic field of poke-type motors is firstly calculated by analytical method. • The magnetic circuit model and iterative method are employed to calculate the permeability. • The analytical expression of each subdomain is derived.. • The proposed method can effectively reduce the predesign stages duration.
Directory of Open Access Journals (Sweden)
G. M. S. ALVA
Full Text Available Brazilian Codes NBR 6118 and NBR 15575 provide practical values for interstory drift limits applied to conventional modeling in order to prevent negative effects in masonry infill walls caused by excessive lateral deformability, however these codes do not account for infill walls in the structural model. The inclusion of infill walls in the proposed model allows for a quantitative evaluation of structural stresses in these walls and an assessment of cracking in these elements (sliding shear diagonal tension and diagonal compression cracking. This paper presents the results of simulations of single-story one-bay infilled R/C frames. The main objective is to show how to check the serviceability limit states under lateral loads when the infill walls are included in the modeling. The results of numerical simulations allowed for an evaluation of stresses and the probable cracking pattern in infill walls. The results also allowed an identification of some advantages and limitations of the NBR 6118 practical procedure based on interstory drift limits.
International Nuclear Information System (INIS)
Liang, Peixin; Chai, Feng; Bi, Yunlong; Pei, Yulong; Cheng, Shukang
2016-01-01
Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization. - Highlights: • The no-load magnetic field of poke-type motors is firstly calculated by analytical method. • The magnetic circuit model and iterative method are employed to calculate the permeability. • The analytical expression of each subdomain is derived.. • The proposed method can effectively reduce the predesign stages duration.
Pannullo, Francesca; Lee, Duncan; Waclawski, Eugene; Leyland, Alastair H
2016-08-01
The long-term impact of air pollution on human health can be estimated from small-area ecological studies in which the health outcome is regressed against air pollution concentrations and other covariates, such as socio-economic deprivation. Socio-economic deprivation is multi-factorial and difficult to measure, and includes aspects of income, education, and housing as well as others. However, these variables are potentially highly correlated, meaning one can either create an overall deprivation index, or use the individual characteristics, which can result in a variety of pollution-health effects. Other aspects of model choice may affect the pollution-health estimate, such as the estimation of pollution, and spatial autocorrelation model. Therefore, we propose a Bayesian model averaging approach to combine the results from multiple statistical models to produce a more robust representation of the overall pollution-health effect. We investigate the relationship between nitrogen dioxide concentrations and cardio-respiratory mortality in West Central Scotland between 2006 and 2012. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.
Directory of Open Access Journals (Sweden)
Anita V. Sotnikova
2015-01-01
Full Text Available Article is devoted to a problem of effective distribution of the general budget of a portfolio between the IT projects which are its part taking into ac-count their priority. The designated problem is actual in view of low results of activity of the consulting companies in the sphere of information technologies.For determination of priority of IT projects the method of analytical networks developed by T. Saati is used. For the purpose of application of this method the system of criteria (indicators reflecting influence of IT projects of a portfolio on the most significant purposes of implementation of IT projects of a portfolio is developed. As system of criteria the key indicators of efficiency defined when developing the Balanced system of indicators which meet above-mentioned requirements are used. The essence of a method of analytical net-works consists in paired comparison of key indicators of efficiency concerning the purpose of realization of a portfolio and IT projects which are a part of a portfolio. Result of use of a method of analytical networks are coefficients of priority of each IT project of a portfolio. The received coefficients of priority of IT projects are used in the offered model of distribution of the budget of a portfolio between IT projects. Thus, the budget of a portfolio of IT projects is distributed between them taking into account not only the income from implementation of each IT project, but also other criteria, important for the IT company, for example: the degree of compliance of the IT project to strategic objectives of the IT company defining expediency of implementation of the IT project; the term of implementation of the IT project determined by the customer. The developed model of distribution of the budget of a portfolio between IT projects is approved on the example of distribution of the budget between IT projects of the portfolio consisting of three IT projects. Taking into account the received
Rigorous approach to the comparison between experiment and theory in Casimir force measurements
International Nuclear Information System (INIS)
Klimchitskaya, G L; Chen, F; Decca, R S; Fischbach, E; Krause, D E; Lopez, D; Mohideen, U; Mostepanenko, V M
2006-01-01
In most experiments on the Casimir force the comparison between measurement data and theory was done using the concept of the root-mean-square deviation, a procedure that has been criticized in the literature. Here we propose a special statistical analysis which should be performed separately for the experimental data and for the results of the theoretical computations. In so doing, the random, systematic and total experimental errors are found as functions of separation, taking into account the distribution laws for each error at 95% confidence. Independently, all theoretical errors are combined to obtain the total theoretical error at the same confidence. Finally, the confidence interval for the differences between theoretical and experimental values is obtained as a function of separation. This rigorous approach is applied to two recent experiments on the Casimir effect
A study into first-year engineering education success using a rigorous mixed methods approach
DEFF Research Database (Denmark)
van den Bogaard, M.E.D.; de Graaff, Erik; Verbraek, Alexander
2015-01-01
The aim of this paper is to combine qualitative and quantitative research methods into rigorous research into student success. Research methods have weaknesses that can be overcome by clever combinations. In this paper we use a situated study into student success as an example of how methods...... using statistical techniques. The main elements of the model were student behaviour and student disposition, which were influenced by the students’ perceptions of the education environment. The outcomes of the qualitative studies were useful in interpreting the outcomes of the structural equation...
Reframing Rigor: A Modern Look at Challenge and Support in Higher Education
Campbell, Corbin M.; Dortch, Deniece; Burt, Brian A.
2018-01-01
This chapter describes the limitations of the traditional notions of academic rigor in higher education, and brings forth a new form of rigor that has the potential to support student success and equity.
From everyday communicative figurations to rigorous audience news repertoires
DEFF Research Database (Denmark)
Kobbernagel, Christian; Schrøder, Kim Christian
2016-01-01
In the last couple of decades there has been an unprecedented explosion of news media platforms and formats, as a succession of digital and social media have joined the ranks of legacy media. We live in a ‘hybrid media system’ (Chadwick, 2013), in which people build their cross-media news...... repertoires from the ensemble of old and new media available. This article presents an innovative mixed-method approach with considerable explanatory power to the exploration of patterns of news media consumption. This approach tailors Q-methodology in the direction of a qualitative study of news consumption......, in which a card sorting exercise serves to translate the participants’ news media preferences into a form that enables the researcher to undertake a rigorous factor-analytical construction of their news consumption repertoires. This interpretive, factor-analytical procedure, which results in the building...
Fast and Rigorous Assignment Algorithm Multiple Preference and Calculation
Directory of Open Access Journals (Sweden)
Ümit Çiftçi
2010-03-01
Full Text Available The goal of paper is to develop an algorithm that evaluates students then places them depending on their desired choices according to dependant preferences. The developed algorithm is also used to implement software. The success and accuracy of the software as well as the algorithm are tested by applying it to ability test at Beykent University. This ability test is repeated several times in order to fill all available places at Fine Art Faculty departments in every academic year. It has been shown that this algorithm is very fast and rigorous after application of 2008-2009 and 2009-20010 academic years.Key Words: Assignment algorithm, student placement, ability test
Desarrollo constitucional, legal y jurisprudencia del principio de rigor subsidiario
Directory of Open Access Journals (Sweden)
Germán Eduardo Cifuentes Sandoval
2013-09-01
Full Text Available In colombia the environment state administration is in charge of environmental national system, SINA, SINA is made up of states entities that coexist beneath a mixed organization of centralization and decentralization. SINA decentralization express itself in a administrative and territorial level, and is waited that entities that function under this structure act in a coordinated way in order to reach suggested objectives in the environmental national politicy. To achieve the coordinated environmental administration through entities that define the SINA, the environmental legislation of Colombia has include three basic principles: 1. The principle of “armorial regional” 2. The principle of “gradationnormative” 3. The principle of “rigorsubsidiaries”. These principles belong to the article 63, law 99 of 1933, and even in the case of the two first, it is possible to find equivalents in other norms that integrate the Colombian legal system, it does not happen in that way with the “ rigor subsidiaries” because its elements are uniques of the environmental normativity and do not seem to be similar to those that make part of the principle of “ subsidiaridad” present in the article 288 of the politic constitution. The “ rigor subsidiaries” give to decentralizates entities certain type of special ability to modify the current environmental legislation to defend the local ecological patrimony. It is an administrative ability with a foundation in the decentralization autonomy that allows to take place of the reglamentary denied of the legislative power with the condition that the new normativity be more demanding that the one that belongs to the central level
Rigorous patient-prosthesis matching of Perimount Magna aortic bioprosthesis.
Nakamura, Hiromasa; Yamaguchi, Hiroki; Takagaki, Masami; Kadowaki, Tasuku; Nakao, Tatsuya; Amano, Atsushi
2015-03-01
Severe patient-prosthesis mismatch, defined as effective orifice area index ≤0.65 cm(2) m(-2), has demonstrated poor long-term survival after aortic valve replacement. Reported rates of severe mismatch involving the Perimount Magna aortic bioprosthesis range from 4% to 20% in patients with a small annulus. Between June 2008 and August 2011, 251 patients (mean age 70.5 ± 10.2 years; mean body surface area 1.55 ± 0.19 m(2)) underwent aortic valve replacement with a Perimount Magna bioprosthesis, with or without concomitant procedures. We performed our procedure with rigorous patient-prosthesis matching to implant a valve appropriately sized to each patient, and carried out annular enlargement when a 19-mm valve did not fit. The bioprosthetic performance was evaluated by transthoracic echocardiography predischarge and at 1 and 2 years after surgery. Overall hospital mortality was 1.6%. Only 5 (2.0%) patients required annular enlargement. The mean follow-up period was 19.1 ± 10.7 months with a 98.4% completion rate. Predischarge data showed a mean effective orifice area index of 1.21 ± 0.20 cm(2) m(-2). Moderate mismatch, defined as effective orifice area index ≤0.85 cm(2) m(-2), developed in 4 (1.6%) patients. None developed severe mismatch. Data at 1 and 2 years showed only two cases of moderate mismatch; neither was severe. Rigorous patient-prosthesis matching maximized the performance of the Perimount Magna, and no severe mismatch resulted in this Japanese population of aortic valve replacement patients. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
On the Faddeev-Yacubovsky model of four nucleon scattering problem with account of spin and isospin
International Nuclear Information System (INIS)
Sharma, V.K.
1976-01-01
The Faddeev-Yacubovsky model of four nucleons taking into account their spin and isospin with the two-channel resonating group approximation, is considered. In this approximation, one employs a completely antisymmetric wave function which can be written as the clustering of d + d and n+He 3 (or p+H 3 ) systems with antisymmetric spin isospin states. The two-nucleon interactions used are of the separable Yamaguchi form in Ssub(1)sup(3) and Ssub(0)sup(3) states. The equations for the states with quantum numbers S=0,1,2 T=0 are obtained. It is shown that with subsequent separable representation of two-particle t-matrix reduces the equations to a set of one-dimensional coupled integral equations. (author)
International Nuclear Information System (INIS)
Bulubasa, Gheorghe; Bidica, Nicolae; Stefanescu, Ioan; Bucur, Ciprian; Deaconu, Mariea
2009-01-01
During the water detritiation process most of the tritium inventory is transferred from water into the gaseous phase, then it is further enriched and finally extracted and safely stored. The control of tritium inventory is an acute issue from several points of view: - Financially - tritium is an expensive material; - Safeguard - tritium is considered as nuclear material of strategic importance; - Safety - tritium is a radioactive material: requirements for documented safety analysis report (to ensure strict limits on the total tritium allowed) and for evaluation of accident consequences associated with that inventory. Large amounts of tritium can be stored, in a very safely manner, as metal tritides. A bench-scale experiment of a tritium storage bed with integrated system for in-situ tritium inventory accountancy was designed and developed at ICSI Rm. Valcea. The calibration curve and the detection limit for this experimental model of tritium storage bed were determined. The experimental results are presented in this paper. (authors)
Wang, Jun; Moumni, Ziad; Zhang, Weihong; Xu, Yingjie; Zaki, Wael
2017-06-01
The paper presents a finite-strain constitutive model for shape memory alloys (SMAs) that accounts for thermomechanical coupling and martensite reorientation. The finite-strain formulation is based on a two-tier, multiplicative decomposition of the deformation gradient into thermal, elastic, and inelastic parts, where the inelastic deformation is further split into phase transformation and martensite reorientation components. A time-discrete formulation of the constitutive equations is proposed and a numerical integration algorithm is presented featuring proper symmetrization of the tensor variables and explicit formulation of the material and spatial tangent operators involved. The algorithm is used for finite element analysis of SMA components subjected to various loading conditions, including uniaxial, non-proportional, isothermal and adiabatic loading cases. The analysis is carried out using the FEA software Abaqus by means of a user-defined material subroutine, which is then utilized to simulate a SMA archwire undergoing large strains and rotations.
Rigorous results in quantum theory of stimulated Raman scattering
International Nuclear Information System (INIS)
Rupasov, V.I.
1993-01-01
The modern theory of stimulated Raman scattering (SRS) of light in resonant media is based on the investigations of appropriate integrable models of the classical field theory by means of the inverse problem method. But, strictly speaking, Raman scattering is a pure spontaneous process and, hence, it is necessary to take into account a quantum nature of the phenomenon. Moreover, there are some questions and problems, for example, the problem of scattered photons statistics, which can be studied only within the framework of the quantum field theory. We have developed an exact quantum theory of SRS for the case of point-like geometry of resonant media (two-level atoms or harmonic oscillators) of the radius r much-lt λ 0 , where λ 0 is the typical wavelength of the light, but all our results are also valid for the case of short extended medium of the length L much-lt l p (l p is the typical size of pulses) when the spatially homogeneous approximation is valid
2008-09-01
values for nuclear explosions at the Semipalatinsk Test Site (STS) will be inferred in the same way they were for NTS. Comparisons between K values...K > ~3 in Poisson media. Most Nevada Test Site (NTS) observations support ~1 < K < 3, and as such the new model predicts lower Ms compared to the...explosions at the two test sites and for two different containment rules are summarized in Table 1 below. F1 is found to be positive for NTS, as we
International Nuclear Information System (INIS)
Gay, J. Rebecca; Korre, Anna
2009-01-01
The authors have previously published a methodology which combines quantitative probabilistic human health risk assessment and spatial statistical methods (geostatistics) to produce an assessment, incorporating uncertainty, of risks to human health from exposure to contaminated land. The model assumes a constant soil to plant concentration factor (CF veg ) when calculating intake of contaminants. This model is modified here to enhance its use in a situation where CF veg varies according to soil pH, as is the case for cadmium. The original methodology uses sequential indicator simulation (SIS) to map soil concentration estimates for one contaminant across a site. A real, age-stratified population is mapped across the contaminated area, and intake of soil contaminants by individuals is calculated probabilistically using an adaptation of the Contaminated Land Exposure Assessment (CLEA) model. The proposed improvement involves not only the geostatistical estimation of the contaminant concentration, but also that of soil pH, which in turn leads to a variable CF veg estimate which influences the human intake results. The results presented demonstrate that taking pH into account can influence the outcome of the risk assessment greatly. It is proposed that a similar adaptation could be used for other combinations of soil variables which influence CF veg .
Goals and Psychological Accounting
DEFF Research Database (Denmark)
Koch, Alexander Karl; Nafziger, Julia
We model how people formulate and evaluate goals to overcome self-control problems. People often attempt to regulate their behavior by evaluating goal-related outcomes separately (in narrow psychological accounts) rather than jointly (in a broad account). To explain this evidence, our theory...... of endogenous narrow or broad psychological accounts combines insights from the literatures on goals and mental accounting with models of expectations-based reference-dependent preferences. By formulating goals the individual creates expectations that induce reference points for task outcomes. These goal......-induced reference points make substandard performance psychologically painful and motivate the individual to stick to his goals. How strong the commitment to goals is depends on the type of psychological account. We provide conditions when it is optimal to evaluate goals in narrow accounts. The key intuition...
Bots, J.M.; Groenland, E.A.G.; Swagerman, D.
2009-01-01
In 2002, the Accountants-in-Business section of the International Federation of Accountants (IFAC) issued the Competency Profiles for Management Accounting Practice and Practitioners report. This “Birkett Report” presents a framework for competency development during the careers of management