A First Life with Computerized Business Simulations
Thavikulwat, Precha
2011-01-01
The author discusses the theoretical lens, origins, and environment of his work on computerized business simulations. Key ideas that inform his work include the two dimensions (control and interaction) of computerized simulation, the two ways of representing a natural process (phenotypical and genotypical) in a simulation, which he defines as a…
Directory of Open Access Journals (Sweden)
Haslinda Mohamed Kamar
2012-03-01
Full Text Available A semi-empirical model for simulating thermal and energy performance of an automotive air-conditioning (AAC system in passenger vehicles has been developed. The model consists of two sections, namely empirical evaporator correlations and dynamic load simulation. The correlations used consider sensible and latent heat transfer performance of the evaporator coil. The correlations were obtained from the experimental data of actual air conditioning system for a compact size passenger car. The sensible heat transfer correlation relates the evaporator air off dry-bulb temperature to inlet air dry-bulb temperature, humidity ratio, evaporator air velocity, condenser inlet air dry-bulb temperature, condenser air velocity and compressor speed. The latent heat transfer correlation relates the coil air-off humidity ratio to the same six independent variables. The dynamic load simulation model was developed based on the z-transfer function method with a one-minute time step. The cooling load calculations were performed using heat gain weighting factors. Heat extraction rate and cabin air dry-bulb temperature calculations were carried out using air temperature weighting factors. The empirical evaporator sensible and latent heat transfer correlations were embedded in the loads calculation program to enable the determination of evaporator inlet and outlet air conditions, the cabin air temperature and relative humidity. Comparisons with road test data indicated that the program was capable of predicting the performance of the automotive air-conditioning system with reasonable accuracy.
Computerized simulation of converter process
Energy Technology Data Exchange (ETDEWEB)
Jalkanen, H.; Suomi, M.L.; Wallgren, M. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Metallurgy
1996-12-31
Converter process is essentially an oxidising refining process aiming in addition to (1) the primary refining action, decarburisation of high carbon iron melt, also to (2) maximal elimination of impurity elements, especially silicon, phosphorus and sulphur, (3) melting of substantial amounts of scrap using the extra heat released in oxidation reactions and (4) to exact final steel temperature control, optimal for further treatments. `Quantitative modelling of such a complex non-stationary chemical process as oxygen converting necessitates extensive formulation of chemical and thermal evolution of the process in connection with the technological properties of the reactor and the process control measures. A comprehensive converter simulation program like CONSIM-3. 1 and its preceding versions that is based on the theoretical and practical knowledge on the process can be used for (1) educating specialists and smelter personnel, (2) planning of the blowing programs, (3) developing and testing of process control systems and after some elaboration and restructuring (4) it can be integrated to static or dynamic process control systems. (orig.) SULA 2 Research Programme; 10 refs.
Computerized molecular modeling of carbohydrates
Computerized molecular modleing continues to increase in capability and applicability to carbohydrates. This chapter covers nomenclature and conformational aspects of carbohydrates, perhaps of greater use to carbohydrate-inexperienced computational chemists. Its comments on various methods and studi...
Graphical Models and Computerized Adaptive Testing.
Mislevy, Robert J.; Almond, Russell G.
This paper synthesizes ideas from the fields of graphical modeling and education testing, particularly item response theory (IRT) applied to computerized adaptive testing (CAT). Graphical modeling can offer IRT a language for describing multifaceted skills and knowledge, and disentangling evidence from complex performances. IRT-CAT can offer…
An Assessment of a Computerized Simulation of Counseling Skills.
Sharf, Richard S.; Lucas, Margaretha
1993-01-01
Developed Computerized Counseling Simulation, simulation of client-counselor interaction. Tested simulation on seven groups with varying degrees of counseling experience: counselors, predoctoral counseling interns, counseling students, first-year counseling students, student peer counselors, undergraduates, and noncounselors (total n=108). Interns…
COMPUTERIZED MODEL OF RISK MANAGEMENT IN BUSINESS
Directory of Open Access Journals (Sweden)
Petrişor MANDU
2011-01-01
Full Text Available The occurrence of risk situation and the manager’s awareness of it are serious threats for the organization and its objectives. Consequently, the manager has to have available, analyze, select and interpret many pieces of information, under stress, before making a decision for avoiding a disaster. Under these circumstances, a computerized model of risk management is the most adequate solution to make the intervention possibilities effective through a quicker and more accurate intervention. The model offers enough confidence and a favorable psychological state for managing risk. In accordance with this model, the risk manager processes the information by means of some operational (mathematical methods and that favors reaching optimum solutions in the shortest delay, based on some estimated anticipations through a rational model.
DeAyala, R. J.; Koch, William R.
A nominal response model-based computerized adaptive testing procedure (nominal CAT) was implemented using simulated data. Ability estimates from the nominal CAT were compared to those from a CAT based upon the three-parameter logistic model (3PL CAT). Furthermore, estimates from both CAT procedures were compared with the known true abilities used…
Computerized classification testing with the Rasch model
Eggen, Theo J.H.M.
2011-01-01
If classification in a limited number of categories is the purpose of testing, computerized adaptive tests (CATs) with algorithms based on sequential statistical testing perform better than estimation-based CATs (e.g., Eggen & Straetmans, 2000). In these computerized classification tests (CCTs), the
Computerized ionospheric tomography with the IRI model
Arikan, Orhan; Arikan, Feza; Erol, Cemil B.
Computerized ionospheric tomography (CIT) is a method to estimate ionospheric electron density distribution by using the global positioning system (GPS) signals recorded by the GPS receivers. Ionospheric electron density is a function of latitude, longitude, height and time. A general approach in CIT is to represent the ionosphere as a linear combination of basis functions. In this study, the model of the ionosphere is obtained from the IRI in latitude and height only. The goal is to determine the best representing basis function from the set of Squeezed Legendre polynomials, truncated Legendre polynomials, Haar Wavelets and singular value decomposition (SVD). The reconstruction algorithms used in this study can be listed as total least squares (TLS), regularized least squares, algebraic reconstruction technique (ART) and a hybrid algorithm where the reconstruction from the TLS algorithm is used as the initial estimate for the ART. The error performance of the reconstruction algorithms are compared with respect to the electron density generated by the IRI-2001 model. In the investigated scenario, the measurements are obtained from the IRI-2001 as the line integral of the electron density profiles, imitating the total electron content estimated from GPS measurements. It has been observed that the minimum error between the reconstructed and model ionospheres depends on both the reconstruction algorithm and the basis functions where the best results have been obtained for the basis functions from the model itself through SVD.
Computerized atmospheric trace contaminant control simulation for manned spacecraft
Perry, J. L.
1993-01-01
Buildup of atmospheric trace contaminants in enclosed volumes such as a spacecraft may lead to potentially serious health problems for the crew members. For this reason, active control methods must be implemented to minimize the concentration of atmospheric contaminants to levels that are considered safe for prolonged, continuous exposure. Designing hardware to accomplish this has traditionally required extensive testing to characterize and select appropriate control technologies. Data collected since the Apollo project can now be used in a computerized performance simulation to predict the performance and life of contamination control hardware to allow for initial technology screening, performance prediction, and operations and contingency studies to determine the most suitable hardware approach before specific design and testing activities begin. The program, written in FORTRAN 77, provides contaminant removal rate, total mass removed, and per pass efficiency for each control device for discrete time intervals. In addition, projected cabin concentration is provided. Input and output data are manipulated using commercial spreadsheet and data graphing software. These results can then be used in analyzing hardware design parameters such as sizing and flow rate, overall process performance and program economics. Test performance may also be predicted to aid test design.
The Nominal Response Model in Computerized Adaptive Testing.
De Ayala, R. J.
One important and promising application of item response theory (IRT) is computerized adaptive testing (CAT). The implementation of a nominal response model-based CAT (NRCAT) was studied. Item pool characteristics for the NRCAT as well as the comparative performance of the NRCAT and a CAT based on the three-parameter logistic (3PL) model were…
Computerized Classification Testing under the Generalized Graded Unfolding Model
Wang, Wen-Chung; Liu, Chen-Wei
2011-01-01
The generalized graded unfolding model (GGUM) has been recently developed to describe item responses to Likert items (agree-disagree) in attitude measurement. In this study, the authors (a) developed two item selection methods in computerized classification testing under the GGUM, the current estimate/ability confidence interval method and the cut…
Smith, Angela; Maizels, Max; Korets, Ruslan; Wiener, John S; Stiener, Michael; Liu, Dennis B; Sutherland, Richard W
2013-12-01
To assess the learning process of combining a web-based video of a simulated surgical procedure with a step-by-step checklist of the same procedure in achieving competency of the simulated technique, in this case a newborn clamp circumcision. Fundamental to this particular learning process is immediate mentor step-by-step feedback which specifically follows the procedure's step-by-step checklist. Pediatric residents naïve to newborn circumcision were enrolled (n = 7). A circumcision simulator, instruments, and web access to the learning module were provided. Residents trained independently and then performed two simulations with the mentor. The first simulation was completed with formative scored feedback. The learner then performed a second scored simulation. All learners showed improvement between the first and second simulation (mean 85.3-97.4). All residents achieved competency (96/100 or greater) by the second simulation. On post-procedure surveys, learners demonstrated increased comfort and reduced apprehension in performing the procedure. Combining a web-accessible video of a procedure, a checklist, and a simulator followed by a single mentor session with immediate formative feedback which follows the steps of the checklist is a useful method to teach the simulation technique of circumcision. We plan to study if this paradigm is transferable to clinical circumcision. Copyright © 2013 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Jack Philip Silva
2016-04-01
Full Text Available Purpose: This study aimed to assess the impact of ultrasound simulation (SonoSim on educational outcomes of an introductory point-of-care ultrasound course compared to hands-on training with live models alone. Methods: Fifty-three internal medicine residents without ultrasound experience were randomly assigned to control or experimental groups. They participated in an introductory point-of-care ultrasound course covering eight topics in eight sessions from June 23, 2014 until July 18, 2014. Both participated in lecture and hands-on training, but experimental group received an hour of computerized simulator training instead of a second hour of hands-on training. We assessed clinical knowledge and image acquisition with written multiple-choice and practical exams, respectively. Of the 53 enrolled, 40 participants (75.5% completed the course and all testing. Results: For the 30-item written exam, mean score of the experimental group was 23.1±3.4 (n=21 vs. 21.8±4.8 (n=19, (P>0 .05. For the practical exam, mean score for both groups was 8.7 out of 16 (P>0 .05. Conclusion: The substitution of eight hours of ultrasound simulation training for live model scanning in a 24 hour training course did not enhance performance on written and image acquisition tests in an introductory ultrasound course for residents. This result suggests that ultrasound simulation technology used as a substitute for live model training on an hour-for-hour basis, did not improve learning outcomes. Further investigation into simulation as a total replacement for live model training will provide a clearer picture of the efficacy of ultrasound simulators in medical education.
Energy Technology Data Exchange (ETDEWEB)
Le Blanc, Katya Lee [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spielman, Zachary Alexander [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rice, Brandon Charles [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2016-04-01
This report describes the installation of two advanced control room technologies, an advanced alarm system and a computerized procedure system, into the Human Systems Simulation Laboratory (HSSL). Installation of these technologies enables future phases of this research by providing a platform to systematically evaluate the effect of these technologies on operator and plant performance.
Plessas, Anastasios
2017-07-10
In preclinical dental education, the acquisition of clinical, technical skills, and the transfer of these skills to the clinic are paramount. Phantom heads provide an efficient way to teach preclinical students dental procedures safely while increasing their dexterity skills considerably. Modern computerized phantom head training units incorporate features of virtual reality technology and the ability to offer concurrent augmented feedback. The aims of this review were to examine and evaluate the dental literature for evidence supporting their use and to discuss the role of augmented feedback versus the facilitator's instruction. Adjunctive training in these units seems to enhance student's learning and skill acquisition and reduce the required faculty supervision time. However, the virtual augmented feedback cannot be used as the sole method of feedback, and the facilitator's input is still critical. Well-powered longitudinal randomized trials exploring the impact of these units on student's clinical performance and issues of cost-effectiveness are warranted.
Computerized adaptive measurement of depression: A simulation study
Directory of Open Access Journals (Sweden)
Mammen Oommen
2004-05-01
Full Text Available Abstract Background Efficient, accurate instruments for measuring depression are increasingly important in clinical practice. We developed a computerized adaptive version of the Beck Depression Inventory (BDI. We examined its efficiency and its usefulness in identifying Major Depressive Episodes (MDE and in measuring depression severity. Methods Subjects were 744 participants in research studies in which each subject completed both the BDI and the SCID. In addition, 285 patients completed the Hamilton Depression Rating Scale. Results The adaptive BDI had an AUC as an indicator of a SCID diagnosis of MDE of 88%, equivalent to the full BDI. The adaptive BDI asked fewer questions than the full BDI (5.6 versus 21 items. The adaptive latent depression score correlated r = .92 with the BDI total score and the latent depression score correlated more highly with the Hamilton (r = .74 than the BDI total score did (r = .70. Conclusions Adaptive testing for depression may provide greatly increased efficiency without loss of accuracy in identifying MDE or in measuring depression severity.
Computerized Simulation in the Social Sciences: A Survey and Evaluation
Garson, G. David
2009-01-01
After years at the periphery of the social sciences, simulation is now emerging as an important and widely used tool for understanding social phenomena. Through simulation, researchers can identify causal effects, specify critical parameter estimates, and clarify the state of the art with respect to what is understood about how processes evolve…
GEANT4 simulations for low energy proton computerized tomography
Energy Technology Data Exchange (ETDEWEB)
Milhoretto, Edney [Federal University of Technology-Parana, UTFPR, Av. Sete de Setembro 3165, Curitiba-PR (Brazil); Schelin, Hugo R. [Federal University of Technology-Parana, UTFPR, Av. Sete de Setembro 3165, Curitiba-PR (Brazil)], E-mail: schelin@utfpr.edu.br; Setti, Joao A.P.; Denyak, Valery; Paschuk, Sergei A. [Federal University of Technology-Parana, UTFPR, Av. Sete de Setembro 3165, Curitiba-PR (Brazil); Evseev, Ivan G.; Assis, Joaquim T. de; Yevseyeva, O. [Polytechnic Institute/UERJ, Rua Alberto Rangel s/n, N. Friburgo, RJ, Brazil 28630-050 (Brazil); Lopes, Ricardo T. [Nuclear Instr. Lab./COPPE/UFRJ, Av. Horacio Macedo 2030, Rio de Janeiro-RJ (Brazil); Vinagre Filho, Ubirajara M. [Institute of Nuclear Engineering-IEN/CNEN, Rua Helio de Almeida 75, Rio de Janeiro-RJ (Brazil)
2010-04-15
This work presents the recent results of computer simulations for the low energy proton beam tomographic scanner installed at the cyclotron CV-28 of IEN/CNEN. New computer simulations were performed in order to adjust the parameters of previous simulation within the first experimental results and to understand some specific effects that affected the form of the final proton energy spectra. To do this, the energy and angular spread of the initial proton beam were added, and the virtual phantom geometry was specified more accurately in relation to the real one. As a result, a more realistic view on the measurements was achieved.
A statistical model for interpreting computerized dynamic posturography data
Feiveson, Alan H.; Metter, E. Jeffrey; Paloski, William H.
2002-01-01
Computerized dynamic posturography (CDP) is widely used for assessment of altered balance control. CDP trials are quantified using the equilibrium score (ES), which ranges from zero to 100, as a decreasing function of peak sway angle. The problem of how best to model and analyze ESs from a controlled study is considered. The ES often exhibits a skewed distribution in repeated trials, which can lead to incorrect inference when applying standard regression or analysis of variance models. Furthermore, CDP trials are terminated when a patient loses balance. In these situations, the ES is not observable, but is assigned the lowest possible score--zero. As a result, the response variable has a mixed discrete-continuous distribution, further compromising inference obtained by standard statistical methods. Here, we develop alternative methodology for analyzing ESs under a stochastic model extending the ES to a continuous latent random variable that always exists, but is unobserved in the event of a fall. Loss of balance occurs conditionally, with probability depending on the realized latent ES. After fitting the model by a form of quasi-maximum-likelihood, one may perform statistical inference to assess the effects of explanatory variables. An example is provided, using data from the NIH/NIA Baltimore Longitudinal Study on Aging.
A computerized coal-water slurry transportation model
Energy Technology Data Exchange (ETDEWEB)
Ljubicic, B.R.; Trostad, B. [Univ. of North Dakota, Grand Forks, ND (United States); Bukurov, Z.; Cvijanovic, P. [Univ. of Novi Sad (Yugoslavia)
1995-12-01
Coal-water fuel (CWF) technology has been developed to the point where full-scale commercialization is just a matter of gaining sufficient market confidence in the price stability of alternate fossil fuels. In order to generalize alternative fuel cost estimates for the desired combinations of processing and/or transportation, a great deal of flexibility is required owing to the understood lack of precision in many of the newly emerging coal technologies. Previously, decisions regarding the sequential and spatial arrangement of the various process steps were made strictly on the basis of experience, simplified analysis, and intuition. Over the last decade, computer modeling has progressed from empirically based correlation to that of intricate mechanistic analysis. Nomograms, charts, tables, and many simple rules of thumb have been made obsolete by the availability of complex computer models. Given the ability to view results graphically in real or near real time, the engineer can immediately verify, from a practical standpoint, whether the initial assumptions and inputs were indeed valid. If the feasibility of a project is being determined in the context of a lack of specific data, the ability to provide a dynamic software-based solution is crucial. Furthermore, the resulting model can be used to establish preliminary operating procedures, test control logic, and train plant/process operators. Presented in this paper is a computerized model capable of estimating the delivered cost of CWF. The model uses coal-specific values, process and transport requirements, terrain factors, and input costs to determine the final operating configuration, bill of materials, and, ultimately, the capital, operating, and unit costs.
Efficient computerized model for dynamic analysis of energy conversion systems
Hughes, R. D.; Lansing, F. L.; Khan, I. R.
1983-02-01
In searching for the optimum parameters that minimize the total life cycle cost of an energy conversion system, various combinations of components are examined and the resulting system performance and associated economics are studied. The systems performance and economics simulation computer program (SPECS) was developed to fill this need. The program simulates the fluid flow, thermal, and electrical characteristics of a system of components on a quasi-steady state basis for a variety of energy conversion systems. A unique approach is used in which the set of characteristic equations is solved by the Newton-Raphson technique. This approach eliminates the tedious iterative loops which are found in comparable programs such as TRNSYS or SOLTES-1. Several efficient features were also incorporated such as the centralized control and energy management scheme, and analogous treatment of energy flow in electrical and mechanical components, and the modeling of components of similar fundamental characteristics using generic subroutines. Initial tests indicate that this model can be used effectively with a relatively small number of time steps and low computer cost.
Energy Technology Data Exchange (ETDEWEB)
Medina, L.S.; Racadio, J.M. [Dept. of Radiology, Children' s Hospital Medical Center, Cincinnati, OH (United States); Schwid, H.A. [Dept. of Anesthesia, Veterans Administration Medical Center, University of Washington, Seattle, WA (United States)
2000-05-01
Background. Awareness and preparedness to handle sedation, analgesia, and contrast-media complications are key in the daily radiology practice. Objective. The purpose is to create a computerized simulator (PC-Windows-based) that uses a graphical interface to reproduce critical incidents in pediatric and adult patients undergoing a wide spectrum of radiologic sedation, analgesia and contrast media complications. Materials and methods. The computerized simulator has a comprehensive set of physiologic and pharmacologic models that predict patient response to management of sedation, analgesia, and contrast-media complications. Photorealistic images, real-time monitors, and mouse-driven information demonstrate in a virtual-reality fashion the behavior of the patient in crisis. Results. Thirteen pediatric and adult radiology scenarios are illustrated encompassing areas such as pediatric radiology, neuroradiology, interventional radiology, and body imaging. The multiple case scenarios evaluate randomly the diagnostic and management performance of the radiologist in critical incidents such as oversedation, anaphylaxis, aspiration, airway obstruction, apnea, agitation, bronchospasm, hypotension, hypertension, cardiac arrest, bradycardia, tachycardia, and myocardial ischemia. The user must control the airway, breathing and circulation, and administer medications in a timely manner to save the simulated patient. On-line help is available in the program to suggest diagnostic and treatment steps to save the patient, and provide information about the medications. A printout of the case management can be obtained for evaluation or educational purposes. Conclusion. The interactive computerized simulator is a new approach to train and evaluate radiologists' responses to critical incidents encountered during radiologic sedation, analgesia, and contrast-media administration. (orig.)
de Beurs, Derek P; Terluin, Berend; Verhaak, Peter F
2017-01-01
Background Efficient screening questionnaires are useful in general practice. Computerized adaptive testing (CAT) is a method to improve the efficiency of questionnaires, as only the items that are particularly informative for a certain responder are dynamically selected. Objective The objective of this study was to test whether CAT could improve the efficiency of the Four-Dimensional Symptom Questionnaire (4DSQ), a frequently used self-report questionnaire designed to assess common psychosocial problems in general practice. Methods A simulation study was conducted using a sample of Dutch patients visiting a general practitioner (GP) with psychological problems (n=379). Responders completed a paper-and-pencil version of the 50-item 4DSQ and a psychometric evaluation was performed to check if the data agreed with item response theory (IRT) assumptions. Next, a CAT simulation was performed for each of the four 4DSQ scales (distress, depression, anxiety, and somatization), based on the given responses as if they had been collected through CAT. The following two stopping rules were applied for the administration of items: (1) stop if measurement precision is below a predefined level, or (2) stop if more than half of the items of the subscale are administered. Results In general, the items of each of the four scales agreed with IRT assumptions. Application of the first stopping rule reduced the length of the questionnaire by 38% (from 50 to 31 items on average). When the second stopping rule was also applied, the total number of items could be reduced by 56% (from 50 to 22 items on average). Conclusions CAT seems useful for improving the efficiency of the 4DSQ by 56% without losing a considerable amount of measurement precision. The CAT version of the 4DSQ may be useful as part of an online assessment to investigate the severity of mental health problems of patients visiting a GP. This simulation study is the first step needed for the development a CAT version of the 4
User’s Guide for COMBIMAN Programs (COMputerized BIomechanical MAN-Model) Version 5
1982-04-01
accomplishing this has been to build mock-ups and use an undetermined number of "representative" test pilots to evaluate the work environment and...the "representative" pilots depends on the availability of pilots and the whims of the designers. The COMputerized Blomechanical MAN-model (COMBIMAN...de- fined with letter S, is the field of stereovision , which is the field visible to both eyes simultaneously. The field defined with letter F
quality of computerized blast load simulation for non-linear dynamic ...
African Journals Online (AJOL)
STRANCOM
purpose, commercial software system ... the analysis model of choice and the stand-off ... This paper addresses the blast-load simulation .... effectively design structures under blast loads. .... Fig. 4: Distribution of Blast Load on Structural Elements.
Computerized models : tools for assessing the future of complex systems?
Ittersum, van M.K.; Sterk, B.
2015-01-01
Models are commonly used to make decisions. At some point all of us will have employed a mental model, that is, a simplification of reality, in an everyday situation. For instance, when we want to make the best decision for the environment and consider whether to buy our vegetables in a large
Use of numerical simulation modeling for perfecting coal industry projects
Energy Technology Data Exchange (ETDEWEB)
Gao, Y.; Abramovich, B.N. (Kitaiskii Gornyi Universitet (China))
1992-02-01
Evaluates digital computerized simulation of operation of control systems for a hydraulic haulage system of the MLS-170 coal cutter loader used in China. A structural scheme of a mathematical model of the hydraulic haulage system is discussed. The BGLS program package for haulage system modeling is described. Modeling haulage system start-up and oil pressure fluctuations and their causes is evaluated. Practical aspects of use of the digital computerized simulation by manufacturers of the MLS-170 haulage system for its modifications are discussed. 3 refs
A cybernetic model of computerization of the cultural heritage
Directory of Open Access Journals (Sweden)
F.G. Filip
2001-08-01
Full Text Available An e-Europe for all should include the facilitation of European citizens to the cultural heritage of Europe and Mediterranean area. This paper proposes a vision for a transition to complex systems combining IT organizations and cultural institutions. It describes the impact and limits and proposes a preliminary cybernetic model to study the relationship between the organizations implied.
Energy Technology Data Exchange (ETDEWEB)
Cassola, V.F.; Hoff, G.; Streck, E.E. [Pontificia Univ. Catolica do Rio Grande do Sul, Porto Alegre, RS (Brazil). Faculdade de Fisica. Grupo de Experimentacao e Simulacao Computacional em Fisica (GESiC)]. E-mail: ghoff@pucrs.br
2004-07-01
This paper shows the development of a virtual anthropomorphous model of head, considering different tissue composition, based in Nuclear Magnetic Resonance (NMR) images. The head original images were acquired in an equipment of NMR GE Sigma Horizon LX 1.5 T Echo Speed, available in the clinic of diagnosis for image SIDI. These images were segmented using routines developed in C++ language. The generated model is a group of 124 matrices of sequential data in format ASCII, where 26 indices evidence different structures. (author)
Hsiao, Ju-Ling; Chen, Rai-Fu
2016-01-16
With the widespread use of information communication technologies, computerized clinical practice guidelines are developed and considered as effective decision supporting tools in assisting the processes of clinical activities. However, the development of computerized clinical practice guidelines in Taiwan is still at the early stage and acceptance level among major users (physicians) of computerized clinical practice guidelines is not satisfactory. This study aims to investigate critical factors influencing physicians' intention to computerized clinical practice guideline use through an integrative model of activity theory and the technology acceptance model. The survey methodology was employed to collect data from physicians of the investigated hospitals that have implemented computerized clinical practice guidelines. A total of 505 questionnaires were sent out, with 238 completed copies returned, indicating a valid response rate of 47.1 %. The collected data was then analyzed by structural equation modeling technique. The results showed that attitudes toward using computerized clinical practice guidelines (γ = 0.451, p critical factors influencing physicians' intention to use computerized clinical practice guidelines, and these factors can explain 68.6 % of the variance in intention to use computerized clinical practice guidelines. This study confirmed that some subject (human) factors, environment (organization) factors, tool (technology) factors mentioned in the activity theory should be carefully considered when introducing computerized clinical practice guidelines. Managers should pay much attention on those identified factors and provide adequate resources and incentives to help the promotion and use of computerized clinical practice guidelines. Through the appropriate use of computerized clinical practice guidelines, the clinical benefits, particularly in improving quality of care and facilitating the clinical processes, will be realized.
Design model of computerized personal decision aid for youth: An expert review
Sarif, Siti Mahfuzah; Ibrahim, Norfiza; Shiratuddin, Norshuhada
2016-08-01
This paper provides a structured review of a design model of a computerized personal decision aid that is intended for youth, named as YouthPDA Design Model. The proposed design model was examined by experts in related areas to ensure the appropriateness of the proposed components and elements, relevancy of the terminologies used, logic of the flow, usability, and practicality of the design model towards development of YouthPDA application. Seven experts from related areas were involved in the evaluation. Discussions on the findings obtained from the expert review are included in this paper. Finally, a revised design model of YouthPDA is proposed as main guidance to develop YouthPDA application.
Energy Technology Data Exchange (ETDEWEB)
Mourao, A.P., E-mail: aprata@des.cefetmg.b [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET/MG), Belo Horizonte, MG (Brazil). Nucleo de Engenharia Hospitalar; Alonso, Thessa C.; Silva, Teogenes A. da, E-mail: alonso@cdtn.b, E-mail: silvata@@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)
2011-10-26
This work presents a comparison among the dose profiles in scanning of computerized tomography of a simulator object of PMMA in its periphery region. To obtain the deposited dose at the PMMA thermoluminescent dosemeters were used positioned at the interior of PMMA simulated object longitudinal to periphery and at the center of cylinder (positions denominated North, South, East, West and Center). Eight scanning were performed of simulator object using the routine protocol for skull in eight different services of radiodiagnostic by TC
Barnea, Nitza; Dori, Yehudit J.
1999-12-01
Computerized molecular modeling (CMM) contributes to the development of visualization skills via vivid animation of three dimensional representations. Its power to illustrate and explore phenomena in chemistry teaching stems from the convenience and simplicity of building molecules of any size and color in a number of presentation styles. A new CMM-based learning environment for teaching and learning chemistry in Israeli high schools has been designed and implemented. Three tenth grade experimental classes used this discovery CMM approach, while two other classes, who studied the same topic in the customary approach, served as a control group. We investigated the effects of using molecular modeling on students' spatial ability, understanding of new concepts related to geometric and symbolic representations and students' perception of the model concept. Each variable was examined for gender differences. Students of the experimental group performed better than control group students in all three performance aspects. Experimental group students scored higher than the control group students in the achievement test on structure and bonding. Students' spatial ability improved in both groups, but students from the experimental group scored higher. For the average students in the two groups the improvement in all three spatial ability sub-tests —paper folding, card rotation, and cube comparison—was significantly higher for the experimental group. Experimental group students gained better insight into the model concept than the control group and could explain more phenomena with the aid of a variety of models. Hence, CMM helps in particular to improve the examined cognitive aspects of the average student population. In most of the achievement and spatial ability tests no significant differences between the genders were found, but in some aspects of model perception and verbal argumentation differences still exist. Experimental group females improved their model
Energy Technology Data Exchange (ETDEWEB)
Felmy, A.R.
1990-04-01
This document is a user's manual and technical reference for the computerized chemical equilibrium model GMIN. GMIN calculates the chemical composition of systems composed of pure solid phases, solid-solution phases, gas phases, adsorbed phases, and the aqueous phase. In the aqueous phase model, the excess solution free energy is modeled by using the equations developed by PITZER and his coworkers, which are valid to high ionic strengths. The Davies equation can also be used. Activity coefficients for nonideal soild-solution phases are calculated using parameters of polynomial expansion in mole fraction of the excess free energy of mixing. The free energy of adsorbed phase species is described by the triple-layer site-binding model. The mathematical algorithm incorporated into GMIN is based upon a constrained minimization of the Gibbs free energy. This algorithm is numerically stable and reliably converges to a free energy minimum. The data base for GMIN contains all standard chemical potentials and Pitzer ion-interaction parameters necessary to model the system Na-K-Ca-Mg-H-Cl-SO{sub 4}-CO{sub 2}-B(OH){sub 4}-H{sub 2}0 at 25{degrees}C.
Rossetti, Manuel D
2015-01-01
Emphasizes a hands-on approach to learning statistical analysis and model building through the use of comprehensive examples, problems sets, and software applications With a unique blend of theory and applications, Simulation Modeling and Arena®, Second Edition integrates coverage of statistical analysis and model building to emphasize the importance of both topics in simulation. Featuring introductory coverage on how simulation works and why it matters, the Second Edition expands coverage on static simulation and the applications of spreadsheets to perform simulation. The new edition als
Liou, Shwu-Ru; Liu, Hsiu-Chen; Tsai, Shu-Ling; Cheng, Ching-Yu; Yu, Wei-Chieh; Chu, Tsui-Ping
2016-04-01
Critical thinking skills and clinical competence are for providing quality patient care. The purpose of this study is to develop the Computerized Model of Performance-Based Measurement system based on the Clinical Reasoning Model. The system can evaluate and identify learning needs for clinical competency and be used as a learning tool to increase clinical competency by using computers. The system includes 10 high-risk, high-volume clinical case scenarios coupled with questions testing clinical reasoning, interpersonal, and technical skills. Questions were sequenced to reflect patients' changing condition and arranged by following the process of collecting and managing information, diagnosing and differentiating urgency of problems, and solving problems. The content validity and known-groups validity was established. The Kuder-Richardson Formula 20 was 0.90 and test-retest reliability was supported (r = 0.78). Nursing educators can use the system to understand students' needs for achieving clinical competence, and therefore, educational plans can be made to better prepare students and facilitate their smooth transition to a future clinical environment. Clinical nurses can use the system to evaluate their performance-based abilities and weakness in clinical reasoning. Appropriate training programs can be designed and implemented to practically promote nurses' clinical competence and quality of patient care.
Computerized simulation of TRPO extraction process treating Chinese high level waste
Institute of Scientific and Technical Information of China (English)
陈靖; 王建晨; 等
1996-01-01
The dependence of main process parameters on each other in TRPO extraction process treating Chinese high level waste has been discussed by computer simulation.A group[ of satisfying process parameters has been obtained and the allowable change ranges have been determined.
Walsh, J. R.; Wetherington, R. D.
1975-01-01
The results of a study on time delays in communication systems applicable to the teleoperator program are presented. Time delay data for 11 specific orbits of interest are shown. These data can be used in the MSFC teleoperator simulator to investigate the effect of time delays in the communications link on the teleoperator control functions.
Stern, Luli; Barnea, Nitza; Shauli, Sofia
2008-01-01
The objective of this study was to evaluate the effect of a dynamic software simulation on the understanding of the kinetic molecular theory by 7th graders. Students in the control group (n = 62) studied a curricular unit that addressed the differences in arrangement and motion of molecules in the three phases of matter. The experimental group (n…
Luealamai, Sutha; Panijpan, Bhinyo
2012-01-01
The authors have developed a computer-based learning module on the unit cell of various types of crystal. The module has two components: the virtual unit cell (VUC) part and the subsequent unit cell hunter part. The VUC is a virtual reality simulation for students to actively arrive at the unit cell from exploring, from a broad view, the crystal…
Luealamai, Sutha; Panijpan, Bhinyo
2012-01-01
The authors have developed a computer-based learning module on the unit cell of various types of crystal. The module has two components: the virtual unit cell (VUC) part and the subsequent unit cell hunter part. The VUC is a virtual reality simulation for students to actively arrive at the unit cell from exploring, from a broad view, the crystal…
Mitchell, Claudia
2010-01-01
Competency standards require baccalaureate nursing graduates to demonstrate knowledge, understanding, and the ability to solve complex problems. In an effort to achieve these program outcomes, educators seek empirical evidence related to the learning process and the effect of innovative teaching strategies, such as simulation, on the learner.…
Computerized ionosphere tomography and numerical simulation%电离层层析成像及数值模拟
Institute of Scientific and Technical Information of China (English)
牛俊; 方涵先
2012-01-01
In this article, numerical simulation of computerized ionosphere to- mography （CIT） is presented. The result shows that, by using the regularization algorithm, the electron distribution of the ionosphere can be inverted well. The reason which affects the accuracy of the reconstruction is also discussed. A para- ment is defined which represents the accuracy of the reconstruction. By discussing the relation between the parament and the number of signals, it is concluded that the lack of information is the main high precision reconstruction result experiment proves that the CIT can electron distribution. reason for the error. In a good condition, a can be obtained. The numerical simulation be widely used in the inversion of ionosphere%利用正则化反演法，对电离层层析成像技术进行了数值模拟．模拟结果表明，正则化反演法能够准确反演出电离层赤道异常的电子密度分布．对正则化反演误差的原因进行了分析，定义了代表重建结果精度的参数并研究其随信号数量的变化，结果显示造成反演误差的主要原因是信息量不足，在提供充足的数据条件下，正则化反演法能够得到很高精度的重建结果．数值模拟实验进一步证明了电离层层析技术在反演电离层电子密度分布中有很大的应用价值．
Boland, J. S., III
1975-01-01
A general simulation program is presented (GSP) involving nonlinear state estimation for space vehicle flight navigation systems. A complete explanation of the iterative guidance mode guidance law, derivation of the dynamics, coordinate frames, and state estimation routines are given so as to fully clarify the assumptions and approximations involved so that simulation results can be placed in their proper perspective. A complete set of computer acronyms and their definitions as well as explanations of the subroutines used in the GSP simulator are included. To facilitate input/output, a complete set of compatable numbers, with units, are included to aid in data development. Format specifications, output data phrase meanings and purposes, and computer card data input are clearly spelled out. A large number of simulation and analytical studies were used to determine the validity of the simulator itself as well as various data runs.
McClintock, David S; Lee, Roy E; Gilbertson, John R
2012-01-01
Whole slide Imaging (WSI) has been touted by many as the future of pathology, with estimates of full adoption occurring sometime in the next 5 to 15 years. While WSI devices have become increasingly capable since their inception, there has been little consideration of how WSI will be implemented and subsequently affect the workflow of high volume histology laboratories. Histology workflow process data was collected from a high-volume histology laboratory (Massachusetts General Hospital) and a process model developed using business process management software. Computerized workflow simulations were performed and total histology process time evaluated under a number of different WSI conditions. Total histology process time increased approximately 10-fold to 20-fold over baseline with the presence of one WSI robot in the histology workflow. Depending on the specifications of the WSI robot, anywhere from 9 to 14 WSI robots were required within the histology workflow to minimize the effects of WSI. Placing a WSI robot into the current workflow of a high-volume histology laboratory with the intent of full adoption is not feasible. Implementing WSI without making significant changes to the current workflow of the histology laboratory would prove to be both disruptive and costly to surgical pathology.
Computer Modeling and Simulation
Energy Technology Data Exchange (ETDEWEB)
Pronskikh, V. S. [Fermilab
2014-05-09
Verification and validation of computer codes and models used in simulation are two aspects of the scientific practice of high importance and have recently been discussed by philosophers of science. While verification is predominantly associated with the correctness of the way a model is represented by a computer code or algorithm, validation more often refers to model’s relation to the real world and its intended use. It has been argued that because complex simulations are generally not transparent to a practitioner, the Duhem problem can arise for verification and validation due to their entanglement; such an entanglement makes it impossible to distinguish whether a coding error or model’s general inadequacy to its target should be blamed in the case of the model failure. I argue that in order to disentangle verification and validation, a clear distinction between computer modeling (construction of mathematical computer models of elementary processes) and simulation (construction of models of composite objects and processes by means of numerical experimenting with them) needs to be made. Holding on to that distinction, I propose to relate verification (based on theoretical strategies such as inferences) to modeling and validation, which shares the common epistemology with experimentation, to simulation. To explain reasons of their intermittent entanglement I propose a weberian ideal-typical model of modeling and simulation as roles in practice. I suggest an approach to alleviate the Duhem problem for verification and validation generally applicable in practice and based on differences in epistemic strategies and scopes
Theory Modeling and Simulation
Energy Technology Data Exchange (ETDEWEB)
Shlachter, Jack [Los Alamos National Laboratory
2012-08-23
Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.
Simulation modeling of carcinogenesis.
Ellwein, L B; Cohen, S M
1992-03-01
A discrete-time simulation model of carcinogenesis is described mathematically using recursive relationships between time-varying model variables. The dynamics of cellular behavior is represented within a biological framework that encompasses two irreversible and heritable genetic changes. Empirical data and biological supposition dealing with both control and experimental animal groups are used together to establish values for model input variables. The estimation of these variables is integral to the simulation process as described in step-by-step detail. Hepatocarcinogenesis in male F344 rats provides the basis for seven modeling scenarios which illustrate the complexity of relationships among cell proliferation, genotoxicity, and tumor risk.
Energy Technology Data Exchange (ETDEWEB)
Casetti, E.; Vogt, W.G.; Mickle, M.H.
1984-01-01
This conference includes papers on the uses of supercomputers, multiprocessors, artificial intelligence and expert systems in various energy applications. Topics considered include knowledge-based expert systems for power engineering, a solar air conditioning laboratory computer system, multivariable control systems, the impact of power system disturbances on computer systems, simulating shared-memory parallel computers, real-time image processing with multiprocessors, and network modeling and simulation of greenhouse solar systems.
Validation of simulation models
DEFF Research Database (Denmark)
Rehman, Muniza; Pedersen, Stig Andur
2012-01-01
In philosophy of science, the interest for computational models and simulations has increased heavily during the past decades. Different positions regarding the validity of models have emerged but the views have not succeeded in capturing the diversity of validation methods. The wide variety...... of models has been somewhat narrow-minded reducing the notion of validation to establishment of truth. This article puts forward the diversity in applications of simulation models that demands a corresponding diversity in the notion of validation....... of models with regards to their purpose, character, field of application and time dimension inherently calls for a similar diversity in validation approaches. A classification of models in terms of the mentioned elements is presented and used to shed light on possible types of validation leading...
改进模型的层析成像算法%IMPROVED MODEL FOR COMPUTERIZED TOMOGRAPHY
Institute of Scientific and Technical Information of China (English)
罗文歆; 朱自强; 赵晓博
2012-01-01
井间地震层析成像技术能够提供钻孔之间地质体的高分辨图像.LTI法与SIRT法相结合是目前使用较广的一种层析成像算法,在此基础上考虑到一个较好的初始模型能提高算法的准确性及效率性,以及在SIRT算法当中如何分配残差能使反演的结果更好,提出了改进模型的层析成像算法.此方法基于LTI法进行射线追踪得到每个接收点在初始模型上的理论走时后,就利用这个理论走时与实际拾取走时的差值以及射线追踪所得到的射线路径,对初始模型进行修正.通过数值模拟实验发现,该算法的效果较原始算法有一定的提高.%Expressway construction in karst developing area, which need exact information of karst. Cross-well seismic computerized tomography is a geophysical exploration method, which use seismic wave to explore the media between wells. It can provide high resolution image of the target. LTI and SIRT are widely used in computerized tomography, improved model method for computerized tomography which s based on that. It consider that a better initial model can improve the accuracy and efficiency of the algorithm, and the distribution of residual error in SIRT can also improve the result of inversion. In some degree, the method improve the result by the numerical modeling experiment.
Ross, Sheldon
2006-01-01
Ross's Simulation, Fourth Edition introduces aspiring and practicing actuaries, engineers, computer scientists and others to the practical aspects of constructing computerized simulation studies to analyze and interpret real phenomena. Readers learn to apply results of these analyses to problems in a wide variety of fields to obtain effective, accurate solutions and make predictions about future outcomes. This text explains how a computer can be used to generate random numbers, and how to use these random numbers to generate the behavior of a stochastic model over time. It presents the statist
Structural considerations for a software life cycle dynamic simulation model
Tausworthe, R. C.; Mckenzie, M.; Lin, C. Y.
1983-01-01
This paper presents the results of a preliminary study into the prospects for simulating the software implementation and maintenance life cycle process, with the aim of producing a computerized tool for use by management and software engineering personnel in project planning, tradeoff studies involving product, environmental, situational, and technological factors, and training. The approach taken is the modular application of a 'flow of resource' concept to the systems dynamics simulation modeling technique. The software life cycle process is represented as a number of stochastic, time-varying, interacting work tasks that each achieves one of the project milestones. Each task is characterized by the item produced, the personnel applied, and the budgetary profile.
Energy Technology Data Exchange (ETDEWEB)
Robert, Y
2007-09-15
This work is a part of study which goal is to realize a computer modelling of the thermomechanical phenomena occurring during the YAG pulse laser welding of titanium alloy (TA6V). The filet welding has different heterogeneities (microstructural and mechanical). In fact, the temperature causes microstructural changes (phase transformations, precipitations) and modifies the mechanical properties. Thermomechanical modelling has thus to be established for the welding of TA6V. (author)
Simulation modeling of reliability and efficiency of mine ventilation systems
Energy Technology Data Exchange (ETDEWEB)
Ushakov, V.K. (Moskovskii Gornyi Institut (USSR))
1991-06-01
Discusses a method developed by the MGI institute for computerized simulation of operation of ventilation systems used in deep underground coal mines. The modeling is aimed at assessment of system reliability and efficiency (probability of failure-free operation and stable air distribution). The following stages of the simulation procedure are analyzed: development of a scheme of the ventilation system (type, aerodynamic characteristics and parameters that describe system elements, e.g. ventilation tunnels, ventilation equipment, main blowers etc., dynamics of these parameters depending among others on mining and geologic conditions), development of mathematical models that describe system characteristics as well as external factors and their effects on the system, development of a structure of the simulated ventilation system, development of an algorithm, development of the final computer program for simulation of a mine ventilation system. Use of the model for forecasting reliability of air supply and efficiency of mine ventilation is discussed. 2 refs.
Directory of Open Access Journals (Sweden)
Mohd Nizam Mazenan
2014-05-01
Full Text Available The aim of this research was to assess the quality and the impact of using computerized speech diagnosis system to overcome the problem of speech articulation disorder among Malaysian context. The prototype of the system is already been develop in order to help Speech Therapist (ST or Speech Language Pathologist (SLP in diagnosis, preventing and treatment for an early stage. Few assessments will be conducted by ST over the patient and mostly the process is still using manual technique whereby the ST relies from their human hearing and their years of experience. This study will surveys the technique and method use by ST at Hospital Sultanah Aminah (HSA (Speech therapist at Speech Therapy Center to help patient that suffer from speech disorder especially in articulation disorder cases. Few experiment and result had also been present in this study where the computerized speech diagnosis system is being tested by using real patient voice sample that been collected from HSA and the students from Sekolah Kebangsaan Taman Universiti Satu.
Dori, Yehudit Judy; Kaberman, Zvia
2012-01-01
Much knowledge in chemistry exists at a molecular level, inaccessible to direct perception. Chemistry instruction should therefore include multiple visual representations, such as molecular models and symbols. This study describes the implementation and assessment of a learning unit designed for 12th grade chemistry honors students. The organic…
DEFF Research Database (Denmark)
Larsen, Gunner Chr.; Madsen Aagaard, Helge; Larsen, Torben J.;
, have the potential to include also mutual wake interaction phenomenons. The basic conjecture behind the dynamic wake meandering (DWM) model is that wake transportation in the atmospheric boundary layer is driven by the large scale lateral- and vertical turbulence components. Based on this conjecture...... and trailed vorticity, has been approached by a simple semi-empirical model essentially based on an eddy viscosity philosophy. Contrary to previous attempts to model wake loading, the DWM approach opens for a unifying description in the sense that turbine power- and load aspects can be treated simultaneously...... methodology has been implemented in the aeroelastic code HAWC2, and example simulations of wake situations, from the small Tjæreborg wind farm, have been performed showing satisfactory agreement between predictions and measurements...
Chatel, D; Martin-Bouyer, Y; Vicaut, E; Bouchoucha, H; Achard, F; Sablayrolles, J L; Carpentier, A
1993-12-01
A quantitative study of cardiovascular anatomy was performed by obtaining three-dimensional reconstructions from regular computed tomography scan images in 15 patients, all candidates for heart transplantation. Volumetric estimates of the cardiovascular structures were obtained from these three-dimensional reconstructions using data directly related to total artificial heart (TAH) implantations. By using computerized three-dimensional modeling of these structures, reproducible measurements of the parameters defining the shape and the anatomical connections of the intrathoracic space available for TAH implantation could be derived. The results are intended to be used for both technical and clinical applications such as computer-assisted drawing of the pericardial cavity and the anatomical connections (useful for improving the design of TAH) and combined statistical calculations (multiple regressions, cluster algorithm) of the measurement results, which will then enable the best selection to be made among two or three TAH models for each patient.
Delay modeling in logic simulation
Energy Technology Data Exchange (ETDEWEB)
Acken, J. M.; Goldstein, L. H.
1980-01-01
As digital integrated circuit size and complexity increases, the need for accurate and efficient computer simulation increases. Logic simulators such as SALOGS (SAndia LOGic Simulator), which utilize transition states in addition to the normal stable states, provide more accurate analysis than is possible with traditional logic simulators. Furthermore, the computational complexity of this analysis is far lower than that of circuit simulation such as SPICE. An eight-value logic simulation environment allows the use of accurate delay models that incorporate both element response and transition times. Thus, timing simulation with an accuracy approaching that of circuit simulation can be accomplished with an efficiency comparable to that of logic simulation. 4 figures.
Streif, Stefan; Staudinger, Wilfried Franz; Oesterhelt, Dieter; Marwan, Wolfgang
2009-02-01
To investigate the responses of Halobacterium salinarum to stimulation with light (phototaxis and photokinesis), we designed an experimental setup consisting of optical devices for automatic video image acquisition and computer-controlled light stimulation, and developed algorithms to analyze physiological responses of the cells. Cells are categorized as motile and nonmotile by a classification scheme based on the square displacement of cell positions. Computerized tracking based on a dynamic model of the stochastic cell movement and a Kalman filter-based algorithm allows smoothed estimates of the cell tracks and the detection of physiological responses to complex stimulus patterns. The setup and algorithms were calibrated which allows quantitative measurements and systematic analysis of cellular sensing and response. Overall, the setup is flexible, extensible, and consists mainly of commercially available products. This facilitates modifications of the setup and algorithms for physiological studies of the motility of cells or microorganisms.
Streif, Stefan; Staudinger, Wilfried Franz; Oesterhelt, Dieter; Marwan, Wolfgang
2009-02-01
To investigate the responses of Halobacterium salinarum to stimulation with light (phototaxis and photokinesis), we designed an experimental setup consisting of optical devices for automatic video image acquisition and computer-controlled light stimulation, and developed algorithms to analyze physiological responses of the cells. Cells are categorized as motile and nonmotile by a classification scheme based on the square displacement of cell positions. Computerized tracking based on a dynamic model of the stochastic cell movement and a Kalman filter-based algorithm allows smoothed estimates of the cell tracks and the detection of physiological responses to complex stimulus patterns. The setup and algorithms were calibrated which allows quantitative measurements and systematic analysis of cellular sensing and response. Overall, the setup is flexible, extensible, and consists mainly of commercially available products. This facilitates modifications of the setup and algorithms for physiological studies of the motility of cells or microorganisms.
Preparations, models, and simulations.
Rheinberger, Hans-Jörg
2015-01-01
This paper proposes an outline for a typology of the different forms that scientific objects can take in the life sciences. The first section discusses preparations (or specimens)--a form of scientific object that accompanied the development of modern biology in different guises from the seventeenth century to the present: as anatomical-morphological specimens, as microscopic cuts, and as biochemical preparations. In the second section, the characteristics of models in biology are discussed. They became prominent from the end of the nineteenth century onwards. Some remarks on the role of simulations--characterising the life sciences of the turn from the twentieth to the twenty-first century--conclude the paper.
Plackmeyer, J.
1982-07-01
The simple way of desulfurizing, the efficient combustion of coal, and low carbon monoxide flue gas content of a fluidized bed combustion installation were studied. The dynamic response of a pressurized fluidized bed should also be studied before any construction is started. The physical-mathematical models of all single components were developed and combined in a total computer program. Starting point was the planned pilot plant with gas turbine engine. Various modifications of the purely air cooled plant as well as the extension to a combined cycle with additional steam turbine were considered. Operating cases were simulated: starting up, increasing from partial load to full load and vice versa, shut down and breakdowns. Results show that all operating cases could be brought under control as well as breakdowns. The constructive precautions and correct plant practice are described.
Notes on modeling and simulation
Energy Technology Data Exchange (ETDEWEB)
Redondo, Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-03-10
These notes present a high-level overview of how modeling and simulation are carried out by practitioners. The discussion is of a general nature; no specific techniques are examined but the activities associated with all modeling and simulation approaches are briefly addressed. There is also a discussion of validation and verification and, at the end, a section on why modeling and simulation are useful.
Managing health care decisions and improvement through simulation modeling.
Forsberg, Helena Hvitfeldt; Aronsson, Håkan; Keller, Christina; Lindblad, Staffan
2011-01-01
Simulation modeling is a way to test changes in a computerized environment to give ideas for improvements before implementation. This article reviews research literature on simulation modeling as support for health care decision making. The aim is to investigate the experience and potential value of such decision support and quality of articles retrieved. A literature search was conducted, and the selection criteria yielded 59 articles derived from diverse applications and methods. Most met the stated research-quality criteria. This review identified how simulation can facilitate decision making and that it may induce learning. Furthermore, simulation offers immediate feedback about proposed changes, allows analysis of scenarios, and promotes communication on building a shared system view and understanding of how a complex system works. However, only 14 of the 59 articles reported on implementation experiences, including how decision making was supported. On the basis of these articles, we proposed steps essential for the success of simulation projects, not just in the computer, but also in clinical reality. We also presented a novel concept combining simulation modeling with the established plan-do-study-act cycle for improvement. Future scientific inquiries concerning implementation, impact, and the value for health care management are needed to realize the full potential of simulation modeling.
Evaluating uncertainty in simulation models
Energy Technology Data Exchange (ETDEWEB)
McKay, M.D.; Beckman, R.J.; Morrison, J.D.; Upton, S.C.
1998-12-01
The authors discussed some directions for research and development of methods for assessing simulation variability, input uncertainty, and structural model uncertainty. Variance-based measures of importance for input and simulation variables arise naturally when using the quadratic loss function of the difference between the full model prediction y and the restricted prediction {tilde y}. The concluded that generic methods for assessing structural model uncertainty do not now exist. However, methods to analyze structural uncertainty for particular classes of models, like discrete event simulation models, may be attainable.
Simulation Model of a Transient
DEFF Research Database (Denmark)
Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte
2005-01-01
This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operation...... in case of such faults. The design of the controller is described and its performance assessed by simulations. The control strategies are explained and the behaviour of the turbine discussed....
Simulation Model of a Transient
DEFF Research Database (Denmark)
Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte
2005-01-01
This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operation...
1977-05-01
SE PAINTSHOP ANO/OR PAINTL0CK6R DMINISTER DAILY WORK ASSIGNMENTS F REQUIREO RECORDS AND LOGS SE IN BOATSWAIN’S MATES DUTIES ADDITIONS TO COSAL...DIFFERENTIAL (HATH) TRAINING AID ASW SYSTEM SIMULATOR-JEZEBEL 6* APS-T3, ULTRASONIC TRAINER FUEL PUiP, AUTOMOTIVE , TRAINING AIO FLASH BLINDNESS
Simulation - modeling - experiment; Simulation - modelisation - experience
Energy Technology Data Exchange (ETDEWEB)
NONE
2004-07-01
After two workshops held in 2001 on the same topics, and in order to make a status of the advances in the domain of simulation and measurements, the main goals proposed for this workshop are: the presentation of the state-of-the-art of tools, methods and experiments in the domains of interest of the Gedepeon research group, the exchange of information about the possibilities of use of computer codes and facilities, about the understanding of physical and chemical phenomena, and about development and experiment needs. This document gathers 18 presentations (slides) among the 19 given at this workshop and dealing with: the deterministic and stochastic codes in reactor physics (Rimpault G.); MURE: an evolution code coupled with MCNP (Meplan O.); neutronic calculation of future reactors at EdF (Lecarpentier D.); advance status of the MCNP/TRIO-U neutronic/thermal-hydraulics coupling (Nuttin A.); the FLICA4/TRIPOLI4 thermal-hydraulics/neutronics coupling (Aniel S.); methods of disturbances and sensitivity analysis of nuclear data in reactor physics, application to VENUS-2 experimental reactor (Bidaud A.); modeling for the reliability improvement of an ADS accelerator (Biarotte J.L.); residual gas compensation of the space charge of intense beams (Ben Ismail A.); experimental determination and numerical modeling of phase equilibrium diagrams of interest in nuclear applications (Gachon J.C.); modeling of irradiation effects (Barbu A.); elastic limit and irradiation damage in Fe-Cr alloys: simulation and experiment (Pontikis V.); experimental measurements of spallation residues, comparison with Monte-Carlo simulation codes (Fallot M.); the spallation target-reactor coupling (Rimpault G.); tools and data (Grouiller J.P.); models in high energy transport codes: status and perspective (Leray S.); other ways of investigation for spallation (Audoin L.); neutrons and light particles production at intermediate energies (20-200 MeV) with iron, lead and uranium targets (Le Colley F
IVOA Recommendation: Simulation Data Model
Lemson, Gerard; Cervino, Miguel; Gheller, Claudio; Gray, Norman; LePetit, Franck; Louys, Mireille; Ooghe, Benjamin; Wagner, Rick; Wozniak, Herve
2014-01-01
In this document and the accompanying documents we describe a data model (Simulation Data Model) describing numerical computer simulations of astrophysical systems. The primary goal of this standard is to support discovery of simulations by describing those aspects of them that scientists might wish to query on, i.e. it is a model for meta-data describing simulations. This document does not propose a protocol for using this model. IVOA protocols are being developed and are supposed to use the model, either in its original form or in a form derived from the model proposed here, but more suited to the particular protocol. The SimDM has been developed in the IVOA Theory Interest Group with assistance of representatives of relevant working groups, in particular DM and Semantics.
Shipman, D. L.
1972-01-01
The development of a model to simulate the information system of a program management type of organization is reported. The model statistically determines the following parameters: type of messages, destinations, delivery durations, type processing, processing durations, communication channels, outgoing messages, and priorites. The total management information system of the program management organization is considered, including formal and informal information flows and both facilities and equipment. The model is written in General Purpose System Simulation 2 computer programming language for use on the Univac 1108, Executive 8 computer. The model is simulated on a daily basis and collects queue and resource utilization statistics for each decision point. The statistics are then used by management to evaluate proposed resource allocations, to evaluate proposed changes to the system, and to identify potential problem areas. The model employs both empirical and theoretical distributions which are adjusted to simulate the information flow being studied.
Meyfroidt, Geert; Güiza, Fabian; Cottem, Dominiek; De Becker, Wilfried; Van Loon, Kristien; Aerts, Jean-Marie; Berckmans, Daniël; Ramon, Jan; Bruynooghe, Maurice; Van den Berghe, Greet
2011-10-25
The intensive care unit (ICU) length of stay (LOS) of patients undergoing cardiac surgery may vary considerably, and is often difficult to predict within the first hours after admission. The early clinical evolution of a cardiac surgery patient might be predictive for his LOS. The purpose of the present study was to develop a predictive model for ICU discharge after non-emergency cardiac surgery, by analyzing the first 4 hours of data in the computerized medical record of these patients with Gaussian processes (GP), a machine learning technique. Non-interventional study. Predictive modeling, separate development (n = 461) and validation (n = 499) cohort. GP models were developed to predict the probability of ICU discharge the day after surgery (classification task), and to predict the day of ICU discharge as a discrete variable (regression task). GP predictions were compared with predictions by EuroSCORE, nurses and physicians. The classification task was evaluated using aROC for discrimination, and Brier Score, Brier Score Scaled, and Hosmer-Lemeshow test for calibration. The regression task was evaluated by comparing median actual and predicted discharge, loss penalty function (LPF) ((actual-predicted)/actual) and calculating root mean squared relative errors (RMSRE). Median (P25-P75) ICU length of stay was 3 (2-5) days. For classification, the GP model showed an aROC of 0.758 which was significantly higher than the predictions by nurses, but not better than EuroSCORE and physicians. The GP had the best calibration, with a Brier Score of 0.179 and Hosmer-Lemeshow p-value of 0.382. For regression, GP had the highest proportion of patients with a correctly predicted day of discharge (40%), which was significantly better than the EuroSCORE (p nurses (p = 0.044) but equivalent to physicians. GP had the lowest RMSRE (0.408) of all predictive models. A GP model that uses PDMS data of the first 4 hours after admission in the ICU of scheduled adult cardiac surgery
Modeling and Simulation with INS.
Roberts, Stephen D.; And Others
INS, the Integrated Network Simulation language, puts simulation modeling into a network framework and automatically performs such programming activities as placing the problem into a next event structure, coding events, collecting statistics, monitoring status, and formatting reports. To do this, INS provides a set of symbols (nodes and branches)…
Energy Technology Data Exchange (ETDEWEB)
Cobb, J.T. Jr.
1979-01-01
Six approaches to devolatilization modeling have been reviewed. Two have been selected for further evaluation: the Vand-type model of Anthony and Howard and the diffusion model of Russel et al. The first of these treats particles under kinetic control only. The second includes some mass transfer control along with kinetic control. Behavior of particles in the SYNTHANE process appears to be in the transition region between kinetic and mass transfer control. Work during the next quarter will focus on the temperature history of average particles in the carbonizer of the SYNTHANE process and on the methods by which the two devolatilization models chosen will be used to describe conversion in the SYNTHANE carbonizer.
Simulation modeling of estuarine ecosystems
Johnson, R. W.
1980-01-01
A simulation model has been developed of Galveston Bay, Texas ecosystem. Secondary productivity measured by harvestable species (such as shrimp and fish) is evaluated in terms of man-related and controllable factors, such as quantity and quality of inlet fresh-water and pollutants. This simulation model used information from an existing physical parameters model as well as pertinent biological measurements obtained by conventional sampling techniques. Predicted results from the model compared favorably with those from comparable investigations. In addition, this paper will discuss remotely sensed and conventional measurements in the framework of prospective models that may be used to study estuarine processes and ecosystem productivity.
Modeling and Simulating Environmental Effects
Guest, Peter S.; Murphree, Tom; Frederickson, Paul A.; Guest, Arlene A.
2012-01-01
MOVES Research & Education Systems Seminar: Presentation; Session 4: Collaborative NWDC/NPS M&S Research; Moderator: Curtis Blais; Modeling and Simulating Environmental Effects; speakers: Peter Guest, Paul Frederickson & Tom Murphree Environmental Effects Group
TREAT Modeling and Simulation Strategy
Energy Technology Data Exchange (ETDEWEB)
DeHart, Mark David [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-09-01
This report summarizes a four-phase process used to describe the strategy in developing modeling and simulation software for the Transient Reactor Test Facility. The four phases of this research and development task are identified as (1) full core transient calculations with feedback, (2) experiment modeling, (3) full core plus experiment simulation and (4) quality assurance. The document describes the four phases, the relationship between these research phases, and anticipated needs within each phase.
Stochastic modeling analysis and simulation
Nelson, Barry L
1995-01-01
A coherent introduction to the techniques for modeling dynamic stochastic systems, this volume also offers a guide to the mathematical, numerical, and simulation tools of systems analysis. Suitable for advanced undergraduates and graduate-level industrial engineers and management science majors, it proposes modeling systems in terms of their simulation, regardless of whether simulation is employed for analysis. Beginning with a view of the conditions that permit a mathematical-numerical analysis, the text explores Poisson and renewal processes, Markov chains in discrete and continuous time, se
Model reduction for circuit simulation
Hinze, Michael; Maten, E Jan W Ter
2011-01-01
Simulation based on mathematical models plays a major role in computer aided design of integrated circuits (ICs). Decreasing structure sizes, increasing packing densities and driving frequencies require the use of refined mathematical models, and to take into account secondary, parasitic effects. This leads to very high dimensional problems which nowadays require simulation times too large for the short time-to-market demands in industry. Modern Model Order Reduction (MOR) techniques present a way out of this dilemma in providing surrogate models which keep the main characteristics of the devi
Ha, Minsu; Nehm, Ross H.; Urban-Lurain, Mark; Merrill, John E.
2011-01-01
Our study explored the prospects and limitations of using machine-learning software to score introductory biology students’ written explanations of evolutionary change. We investigated three research questions: 1) Do scoring models built using student responses at one university function effectively at another university? 2) How many human-scored student responses are needed to build scoring models suitable for cross-institutional application? 3) What factors limit computer-scoring efficacy, and how can these factors be mitigated? To answer these questions, two biology experts scored a corpus of 2556 short-answer explanations (from biology majors and nonmajors) at two universities for the presence or absence of five key concepts of evolution. Human- and computer-generated scores were compared using kappa agreement statistics. We found that machine-learning software was capable in most cases of accurately evaluating the degree of scientific sophistication in undergraduate majors’ and nonmajors’ written explanations of evolutionary change. In cases in which the software did not perform at the benchmark of “near-perfect” agreement (kappa > 0.80), we located the causes of poor performance and identified a series of strategies for their mitigation. Machine-learning software holds promise as an assessment tool for use in undergraduate biology education, but like most assessment tools, it is also characterized by limitations. PMID:22135372
Innovations in Computerized Assessment.
Drasgow, Fritz, Ed.; Olson-Buchanan, Julie B., Ed.
Chapters in this book present the challenges and dilemmas faced by researchers as they created new computerized assessments, focusing on issues addressed in developing, scoring, and administering the assessments. Chapters are: (1) "Beyond Bells and Whistles; An Introduction to Computerized Assessment" (Julie B. Olson-Buchanan and Fritz Drasgow);…
A VRLA battery simulation model
Energy Technology Data Exchange (ETDEWEB)
Pascoe, P.E.; Anbuky, A.H. [Invensys Energy Systems NZ Limited, Christchurch (New Zealand)
2004-05-01
A valve regulated lead acid (VRLA) battery simulation model is an invaluable tool for the standby power system engineer. The obvious use for such a model is to allow the assessment of battery performance. This may involve determining the influence of cells suffering from state of health (SOH) degradation on the performance of the entire string, or the running of test scenarios to ascertain the most suitable battery size for the application. In addition, it enables the engineer to assess the performance of the overall power system. This includes, for example, running test scenarios to determine the benefits of various load shedding schemes. It also allows the assessment of other power system components, either for determining their requirements and/or vulnerabilities. Finally, a VRLA battery simulation model is vital as a stand alone tool for educational purposes. Despite the fundamentals of the VRLA battery having been established for over 100 years, its operating behaviour is often poorly understood. An accurate simulation model enables the engineer to gain a better understanding of VRLA battery behaviour. A system level multipurpose VRLA battery simulation model is presented. It allows an arbitrary battery (capacity, SOH, number of cells and number of strings) to be simulated under arbitrary operating conditions (discharge rate, ambient temperature, end voltage, charge rate and initial state of charge). The model accurately reflects the VRLA battery discharge and recharge behaviour. This includes the complex start of discharge region known as the coup de fouet. (author)
Modelling and Simulation: An Overview
M.J. McAleer (Michael); F. Chan (Felix); L. Oxley (Les)
2013-01-01
textabstractThe papers in this special issue of Mathematics and Computers in Simulation cover the following topics: improving judgmental adjustment of model-based forecasts, whether forecast updates are progressive, on a constrained mixture vector autoregressive model, whether all estimators are bor
General introduction to simulation models
DEFF Research Database (Denmark)
Hisham Beshara Halasa, Tariq; Boklund, Anette
2012-01-01
Monte Carlo simulation can be defined as a representation of real life systems to gain insight into their functions and to investigate the effects of alternative conditions or actions on the modeled system. Models are a simplification of a system. Most often, it is best to use experiments and field...
Modelling, simulating and optimizing Boilers
DEFF Research Database (Denmark)
Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels
2003-01-01
of the boiler has been developed and simulations carried out by means of the Matlab integration routines. The model is prepared as a dynamic model consisting of both ordinary differential equations and algebraic equations, together formulated as a Differential-Algebraic- Equation system. Being able to operate...
Huang, Chien-Yu; Tung, Li-Chen; Chou, Yeh-Tai; Chou, Willy; Chen, Kuan-Lin; Hsieh, Ching-Lin
2017-07-27
This study aimed at improving the utility of the fine motor subscale of the comprehensive developmental inventory for infants and toddlers (CDIIT) by developing a computerized adaptive test of fine motor skills. We built an item bank for the computerized adaptive test of fine motor skills using the fine motor subscale of the CDIIT items fitting the Rasch model. We also examined the psychometric properties and efficiency of the computerized adaptive test of fine motor skills with simulated computerized adaptive tests. Data from 1742 children with suspected developmental delays were retrieved. The mean scores of the fine motor subscale of the CDIIT increased along with age groups (mean scores = 1.36-36.97). The computerized adaptive test of fine motor skills contains 31 items meeting the Rasch model's assumptions (infit mean square = 0.57-1.21, outfit mean square = 0.11-1.17). For children of 6-71 months, the computerized adaptive test of fine motor skills had high Rasch person reliability (average reliability >0.90), high concurrent validity (rs = 0.67-0.99), adequate to excellent diagnostic accuracy (area under receiver operating characteristic = 0.71-1.00), and large responsiveness (effect size = 1.05-3.93). The computerized adaptive test of fine motor skills used 48-84% fewer items than the fine motor subscale of the CDIIT. The computerized adaptive test of fine motor skills used fewer items for assessment but was as reliable and valid as the fine motor subscale of the CDIIT. Implications for Rehabilitation We developed a computerized adaptive test based on the comprehensive developmental inventory for infants and toddlers (CDIIT) for assessing fine motor skills. The computerized adaptive test has been shown to be efficient because it uses fewer items than the original measure and automatically presents the results right after the test is completed. The computerized adaptive test is as reliable and valid as the CDIIT.
Directory of Open Access Journals (Sweden)
Wang Weng-Chung
2009-05-01
Full Text Available Abstract Background The aim of this study was to verify the effectiveness and efficacy of saving time and reducing burden for patients, nurses, and even occupational therapists through computer adaptive testing (CAT. Methods Based on an item bank of the Barthel Index (BI and the Frenchay Activities Index (FAI for assessing comprehensive activities of daily living (ADL function in stroke patients, we developed a visual basic application (VBA-Excel CAT module, and (1 investigated whether the averaged test length via CAT is shorter than that of the traditional all-item-answered non-adaptive testing (NAT approach through simulation, (2 illustrated the CAT multimedia on a tablet PC showing data collection and response errors of ADL clinical functional measures in stroke patients, and (3 demonstrated the quality control of endorsing scale with fit statistics to detect responding errors, which will be further immediately reconfirmed by technicians once patient ends the CAT assessment. Results The results show that endorsed items could be shorter on CAT (M = 13.42 than on NAT (M = 23 at 41.64% efficiency in test length. However, averaged ability estimations reveal insignificant differences between CAT and NAT. Conclusion This study found that mobile nursing services, placed at the bedsides of patients could, through the programmed VBA-Excel CAT module, reduce the burden to patients and save time, more so than the traditional NAT paper-and-pencil testing appraisals.
Vehicle dynamics modeling and simulation
Schramm, Dieter; Bardini, Roberto
2014-01-01
The authors examine in detail the fundamentals and mathematical descriptions of the dynamics of automobiles. In this context different levels of complexity will be presented, starting with basic single-track models up to complex three-dimensional multi-body models. A particular focus is on the process of establishing mathematical models on the basis of real cars and the validation of simulation results. The methods presented are explained in detail by means of selected application scenarios.
Stochastic models: theory and simulation.
Energy Technology Data Exchange (ETDEWEB)
Field, Richard V., Jr.
2008-03-01
Many problems in applied science and engineering involve physical phenomena that behave randomly in time and/or space. Examples are diverse and include turbulent flow over an aircraft wing, Earth climatology, material microstructure, and the financial markets. Mathematical models for these random phenomena are referred to as stochastic processes and/or random fields, and Monte Carlo simulation is the only general-purpose tool for solving problems of this type. The use of Monte Carlo simulation requires methods and algorithms to generate samples of the appropriate stochastic model; these samples then become inputs and/or boundary conditions to established deterministic simulation codes. While numerous algorithms and tools currently exist to generate samples of simple random variables and vectors, no cohesive simulation tool yet exists for generating samples of stochastic processes and/or random fields. There are two objectives of this report. First, we provide some theoretical background on stochastic processes and random fields that can be used to model phenomena that are random in space and/or time. Second, we provide simple algorithms that can be used to generate independent samples of general stochastic models. The theory and simulation of random variables and vectors is also reviewed for completeness.
Computational Modeling of Simulation Tests.
1980-06-01
Mexico , March 1979. 14. Kinney, G. F.,.::. IeiN, .hoce 1h Ir, McMillan, p. 57, 1962. 15. Courant and Friedrichs, ,U: r. on moca an.: Jho...AD 79 275 NEW MEXICO UNIV ALBUGUERGUE ERIC H WANG CIVIL ENGINE-ETC F/6 18/3 COMPUTATIONAL MODELING OF SIMULATION TESTS.(U) JUN 80 6 LEIGH, W CHOWN, B...COMPUTATIONAL MODELING OF SIMULATION TESTS00 0G. Leigh W. Chown B. Harrison Eric H. Wang Civil Engineering Research Facility University of New Mexico
SIMULATION OF COLLECTIVE RISK MODEL
Directory of Open Access Journals (Sweden)
Viera Pacáková
2007-12-01
Full Text Available The article focuses on providing brief theoretical definitions of the basic terms and methods of modeling and simulations of insurance risks in non-life insurance by means of mathematical and statistical methods using statistical software. While risk assessment of insurance company in connection with its solvency is a rather complex and comprehensible problem, its solution starts with statistical modeling of number and amount of individual claims. Successful solution of these fundamental problems enables solving of curtail problems of insurance such as modeling and simulation of collective risk, premium an reinsurance premium calculation, estimation of probabiliy of ruin etc. The article also presents some essential ideas underlying Monte Carlo methods and their applications to modeling of insurance risk. Solving problem is to find the probability distribution of the collective risk in non-life insurance portfolio. Simulation of the compound distribution function of the aggregate claim amount can be carried out, if the distibution functions of the claim number process and the claim size are assumed given. The Monte Carlo simulation is suitable method to confirm the results of other methods and for treatments of catastrophic claims, when small collectives are studied. Analysis of insurance risks using risk theory is important part of the project Solvency II. Risk theory is analysis of stochastic features of non-life insurance process. The field of application of risk theory has grown rapidly. There is a need to develop the theory into form suitable for practical purposes and demostrate their application. Modern computer simulation techniques open up a wide field of practical applications for risk theory concepts, without requiring the restricive assumptions and sophisticated mathematics. This article presents some comparisons of the traditional actuarial methods and of simulation methods of the collective risk model.
Chang, Yen-Hsiang; Lee, Hao; Lin, Chun-Li
2015-11-01
This study utilizes micro-computerized tomographic (micro-CT) and finite element (FE) sub-modeling analyses to investigate the micro-mechanical behavior associated with voids/bubbles stress behavior at the luting material layer to understand the early damage in a root canal treated premolar. 3-dimensional finite element (FE) models of a macro-root canal treated premolar and two sub-models at the luting material layer to provide the void/bubble distribution and dimensions were constructed from micro-CT images and simulated to receive axial and lateral forces. The boundary conditions for the sub-models were determined from the macro-premolar model results and applied in sub-modeling analysis. The first principal stresses for the dentin, luting material layer and post in macro-premolar model and for luting material void/bubble in sub-models were recorded. The simulated results revealed that the macro-premolar model dramatically underestimated the luting material stress because the voids/bubbles at the adhesive layer cannot be captured due to coarse mesh and high stress gradient and the variations between sub- and macro-models ranging from 2.65 to 4.5 folds under lateral load at the mapping location. Stress concentrations were found at the edge of the voids/bubbles and values over 20 MPa in sub-modeling analysis immediately caused the luting material failure/micro-crack. This study establishes that micro-CT and FE sub-modeling techniques can be used to simulate the stress pattern at the micro-scale luting material layer in a root canal treated premolar, suggesting that attention must be paid to resin luting material initial failure/debonding when large voids/bubbles are generated during luting procedures.
MODELLING, SIMULATING AND OPTIMIZING BOILERS
DEFF Research Database (Denmark)
Sørensen, K.; Condra, T.; Houbak, Niels
2003-01-01
This paper describes the modelling, simulating and optimizing including experimental verification as being carried out as part of a Ph.D. project being written resp. supervised by the authors. The work covers dynamic performance of both water-tube boilers and fire tube boilers. A detailed dynamic...... model of the boiler has been developed and simulations carried out by means of the Matlab integration routines. The model is prepared as a dynamic model consisting of both ordinary differential equations and algebraic equations, together formulated as a Differential-Algebraic-Equation system. Being able...... to operate a boiler plant dynamically means that the boiler designs must be able to absorb any fluctuations in water level and temperature gradients resulting from the pressure change in the boiler. On the one hand a large water-/steam space may be required, i.e. to build the boiler as big as possible. Due...
Intelligent Mobility Modeling and Simulation
2015-03-04
cog.cs.drexel.edu/act-r/index.html) •Models sensory / motor performance of human driver or teleoperator 27UNCLASSIFIED: Distribution Statement A. Approved for...U.S. ARMY TANK AUTOMOTIVE RESEARCH, DEVELOPMENT AND ENGINEERING CENTER Intelligent Mobility Modeling and Simulation 1 Dr. P. Jayakumar, S. Arepally...Prescribed by ANSI Std Z39-18 Contents 1. Mobility - Autonomy - Latency Relationship 2. Machine - Human Partnership 3. Development of Shared Control
MODELLING, SIMULATING AND OPTIMIZING BOILERS
DEFF Research Database (Denmark)
Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels
2004-01-01
on the boiler) have been dened. Furthermore a number of constraints related to: minimum and maximum boiler load gradient, minimum boiler size, Shrinking and Swelling and Steam Space Load have been dened. For dening the constraints related to the required boiler volume a dynamic model for simulating the boiler...... performance has been developed. Outputs from the simulations are shrinking and swelling of water level in the drum during for example a start-up of the boiler, these gures combined with the requirements with respect to allowable water level uctuations in the drum denes the requirements with respect to drum...... size. The model has been formulated with a specied building-up of the pressure during the start-up of the plant, i.e. the steam production during start-up of the boiler is output from the model. The steam outputs together with requirements with respect to steam space load have been utilized to dene...
Modeling and Simulation of Nanoindentation
Huang, Sixie; Zhou, Caizhi
2017-08-01
Nanoindentation is a hardness test method applied to small volumes of material which can provide some unique effects and spark many related research activities. To fully understand the phenomena observed during nanoindentation tests, modeling and simulation methods have been developed to predict the mechanical response of materials during nanoindentation. However, challenges remain with those computational approaches, because of their length scale, predictive capability, and accuracy. This article reviews recent progress and challenges for modeling and simulation of nanoindentation, including an overview of molecular dynamics, the quasicontinuum method, discrete dislocation dynamics, and the crystal plasticity finite element method, and discusses how to integrate multiscale modeling approaches seamlessly with experimental studies to understand the length-scale effects and microstructure evolution during nanoindentation tests, creating a unique opportunity to establish new calibration procedures for the nanoindentation technique.
Multiscale Stochastic Simulation and Modeling
Energy Technology Data Exchange (ETDEWEB)
James Glimm; Xiaolin Li
2006-01-10
Acceleration driven instabilities of fluid mixing layers include the classical cases of Rayleigh-Taylor instability, driven by a steady acceleration and Richtmyer-Meshkov instability, driven by an impulsive acceleration. Our program starts with high resolution methods of numerical simulation of two (or more) distinct fluids, continues with analytic analysis of these solutions, and the derivation of averaged equations. A striking achievement has been the systematic agreement we obtained between simulation and experiment by using a high resolution numerical method and improved physical modeling, with surface tension. Our study is accompanies by analysis using stochastic modeling and averaged equations for the multiphase problem. We have quantified the error and uncertainty using statistical modeling methods.
Assessment of Molecular Modeling & Simulation
Energy Technology Data Exchange (ETDEWEB)
None
2002-01-03
This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materials modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.
Animal models for simulating weightlessness
Morey-Holton, E.; Wronski, T. J.
1982-01-01
NASA has developed a rat model to simulate on earth some aspects of the weightlessness alterations experienced in space, i.e., unloading and fluid shifts. Comparison of data collected from space flight and from the head-down rat suspension model suggests that this model system reproduces many of the physiological alterations induced by space flight. Data from various versions of the rat model are virtually identical for the same parameters; thus, modifications of the model for acute, chronic, or metabolic studies do not alter the results as long as the critical components of the model are maintained, i.e., a cephalad shift of fluids and/or unloading of the rear limbs.
Simulation Tool for Inventory Models: SIMIN
Pratiksha Saxen; Tulsi Kushwaha
2014-01-01
In this paper, an integrated simulation optimization model for the inventory system is developed. An effective algorithm is developed to evaluate and analyze the back-end stored simulation results. This paper proposes simulation tool SIMIN (Inventory Simulation) to simulate inventory models. SIMIN is a tool which simulates and compares the results of different inventory models. To overcome various practical restrictive assumptions, SIMIN provides values for a number of performance measurement...
Standard for Models and Simulations
Steele, Martin J.
2016-01-01
This NASA Technical Standard establishes uniform practices in modeling and simulation to ensure essential requirements are applied to the design, development, and use of models and simulations (MS), while ensuring acceptance criteria are defined by the program project and approved by the responsible Technical Authority. It also provides an approved set of requirements, recommendations, and criteria with which MS may be developed, accepted, and used in support of NASA activities. As the MS disciplines employed and application areas involved are broad, the common aspects of MS across all NASA activities are addressed. The discipline-specific details of a given MS should be obtained from relevant recommended practices. The primary purpose is to reduce the risks associated with MS-influenced decisions by ensuring the complete communication of the credibility of MS results.
Demerdash, N. A. O.; Nehl, T. W.
1979-01-01
A mathematical model was developed and computerized simulations were obtained for a brushless dc motor. Experimentally obtained oscillograms of the machine phase currents are presented and the corresponding current and voltage waveforms for various modes of operation of the motor are presented and discussed.
Model for Simulation Atmospheric Turbulence
DEFF Research Database (Denmark)
Lundtang Petersen, Erik
1976-01-01
A method that produces realistic simulations of atmospheric turbulence is developed and analyzed. The procedure makes use of a generalized spectral analysis, often called a proper orthogonal decomposition or the Karhunen-Loève expansion. A set of criteria, emphasizing a realistic appearance, a co....... The method is unique in modeling the three velocity components simultaneously, and it is found that important cross-statistical features are reasonably well-behaved. It is concluded that the model provides a practical, operational simulator of atmospheric turbulence.......A method that produces realistic simulations of atmospheric turbulence is developed and analyzed. The procedure makes use of a generalized spectral analysis, often called a proper orthogonal decomposition or the Karhunen-Loève expansion. A set of criteria, emphasizing a realistic appearance......, a correct spectral shape, and non-Gaussian statistics, is selected in order to evaluate the model turbulence. An actual turbulence record is analyzed in detail providing both a standard for comparison and input statistics for the generalized spectral analysis, which in turn produces a set of orthonormal...
DEFF Research Database (Denmark)
2013-01-01
using a Computerized Numerical Control (CNC) simulator. The study will use data from the German-Malaysian Institute in Malaysia. The findings of this study will provide a general guideline for educators in Technical and Vocational Education and Training (TVET) institutions in implementing Problem......Industry has a great need for highly skilled technicians that graduate from Technical Vocational Education and Training (TVET). In a study started at Aalborg University (AAU) the purpose is to evaluate the effectiveness of the (PBL) approach on students’ skills, in particular on programming course...
Advances in Intelligent Modelling and Simulation Simulation Tools and Applications
Oplatková, Zuzana; Carvalho, Marco; Kisiel-Dorohinicki, Marek
2012-01-01
The human capacity to abstract complex systems and phenomena into simplified models has played a critical role in the rapid evolution of our modern industrial processes and scientific research. As a science and an art, Modelling and Simulation have been one of the core enablers of this remarkable human trace, and have become a topic of great importance for researchers and practitioners. This book was created to compile some of the most recent concepts, advances, challenges and ideas associated with Intelligent Modelling and Simulation frameworks, tools and applications. The first chapter discusses the important aspects of a human interaction and the correct interpretation of results during simulations. The second chapter gets to the heart of the analysis of entrepreneurship by means of agent-based modelling and simulations. The following three chapters bring together the central theme of simulation frameworks, first describing an agent-based simulation framework, then a simulator for electrical machines, and...
Verifying and Validating Simulation Models
Energy Technology Data Exchange (ETDEWEB)
Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-02-23
This presentation is a high-level discussion of the Verification and Validation (V&V) of computational models. Definitions of V&V are given to emphasize that “validation” is never performed in a vacuum; it accounts, instead, for the current state-of-knowledge in the discipline considered. In particular comparisons between physical measurements and numerical predictions should account for their respective sources of uncertainty. The differences between error (bias), aleatoric uncertainty (randomness) and epistemic uncertainty (ignorance, lack-of- knowledge) are briefly discussed. Four types of uncertainty in physics and engineering are discussed: 1) experimental variability, 2) variability and randomness, 3) numerical uncertainty and 4) model-form uncertainty. Statistical sampling methods are available to propagate, and analyze, variability and randomness. Numerical uncertainty originates from the truncation error introduced by the discretization of partial differential equations in time and space. Model-form uncertainty is introduced by assumptions often formulated to render a complex problem more tractable and amenable to modeling and simulation. The discussion concludes with high-level guidance to assess the “credibility” of numerical simulations, which stems from the level of rigor with which these various sources of uncertainty are assessed and quantified.
MODELLING, SIMULATING AND OPTIMIZING BOILERS
DEFF Research Database (Denmark)
Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels
2004-01-01
on the boiler) have been dened. Furthermore a number of constraints related to: minimum and maximum boiler load gradient, minimum boiler size, Shrinking and Swelling and Steam Space Load have been dened. For dening the constraints related to the required boiler volume a dynamic model for simulating the boiler...... size. The model has been formulated with a specied building-up of the pressure during the start-up of the plant, i.e. the steam production during start-up of the boiler is output from the model. The steam outputs together with requirements with respect to steam space load have been utilized to dene...... of the boiler is (with an acceptable accuracy) proportional with the volume of the boiler. For the dynamic operation capability a cost function penalizing limited dynamic operation capability and vise-versa has been dened. The main idea is that it by mean of the parameters in this function is possible to t its...
Simulated annealing model of acupuncture
Shang, Charles; Szu, Harold
2015-05-01
The growth control singularity model suggests that acupuncture points (acupoints) originate from organizers in embryogenesis. Organizers are singular points in growth control. Acupuncture can cause perturbation of a system with effects similar to simulated annealing. In clinical trial, the goal of a treatment is to relieve certain disorder which corresponds to reaching certain local optimum in simulated annealing. The self-organizing effect of the system is limited and related to the person's general health and age. Perturbation at acupoints can lead a stronger local excitation (analogous to higher annealing temperature) compared to perturbation at non-singular points (placebo control points). Such difference diminishes as the number of perturbed points increases due to the wider distribution of the limited self-organizing activity. This model explains the following facts from systematic reviews of acupuncture trials: 1. Properly chosen single acupoint treatment for certain disorder can lead to highly repeatable efficacy above placebo 2. When multiple acupoints are used, the result can be highly repeatable if the patients are relatively healthy and young but are usually mixed if the patients are old, frail and have multiple disorders at the same time as the number of local optima or comorbidities increases. 3. As number of acupoints used increases, the efficacy difference between sham and real acupuncture often diminishes. It predicted that the efficacy of acupuncture is negatively correlated to the disease chronicity, severity and patient's age. This is the first biological - physical model of acupuncture which can predict and guide clinical acupuncture research.
Shen, Hua; Zhu, Yong; Qin, Kai-Rong
2016-12-01
The electrical conductivity of pulsatile blood flow in arteries is an important factor for the application of the electrical impedance measurement system in clinical settings. The electrical conductivity of pulsatile blood flow depends not only on blood-flow-induced red blood cell (RBC) orientation and deformation but also on artery wall motion. Numerous studies have investigated the conductivity of pulsatile blood based on a rigid tube model, in which the effects of wall motion on blood conductivity are not considered. In this study, integrating Ling and Atabek's local flow theory and Maxwell-Fricke theory, we develop an elastic tube model to explore the effects of wall motion as well as blood flow velocity on blood conductivity. The simulation results suggest that wall motion, rather than blood flow velocity, is the primary factor that affects the conductivity of flowing blood in arteries.
Demerdash, N. A.; Nehl, T. W.
1980-01-01
A comprehensive digital model for the analysis and possible optimization of the closed loop dynamic (instantaneous) performance of a power conditioner fed, brushless dc motor powered, electromechanical actuator system (EMA) is presented. This model was developed for the simulation of the dynamic performance of an actual prototype EMA built for NASA-JSC as a possible alternative to hydraulic actuators for consideration in Space Shuttle Orbiter applications. Excellent correlation was achieved between numerical model simulation and experimental test results obtained from the actual hardware. These results include: various current and voltage waveforms in the machine-power conditioner (MPC) unit, flap position as well as other control loop variables in response to step commands of change of flap position. These results with consequent conclusions are detailed in the paper.
Roca-Pardiñas, Javier; Cadarso-Suárez, Carmen; Tahoces, Pablo G; Lado, María J
2009-01-30
In many biomedical applications, interest lies in being able to distinguish between two possible states of a given response variable, depending on the values of certain continuous predictors. If the number of predictors, p, is high, or if there is redundancy among them, it then becomes important to decide on the selection of the best subset of predictors that will be able to obtain the models with greatest discrimination capacity. With this aim in mind, logistic generalized additive models were considered and receiver operating characteristic (ROC) curves were applied in order to determine and compare the discriminatory capacity of such models. This study sought to develop bootstrap-based tests that allow for the following to be ascertained: (a) the optimal number q < or = p of predictors; and (b) the model or models including q predictors, which display the largest AUC (area under the ROC curve). A simulation study was conducted to verify the behaviour of these tests. Finally, the proposed method was applied to a computer-aided diagnostic system dedicated to early detection of breast cancer. Copyright (c) 2008 John Wiley & Sons, Ltd.
Uterine Contraction Modeling and Simulation
Liu, Miao; Belfore, Lee A.; Shen, Yuzhong; Scerbo, Mark W.
2010-01-01
Building a training system for medical personnel to properly interpret fetal heart rate tracing requires developing accurate models that can relate various signal patterns to certain pathologies. In addition to modeling the fetal heart rate signal itself, the change of uterine pressure that bears strong relation to fetal heart rate and provides indications of maternal and fetal status should also be considered. In this work, we have developed a group of parametric models to simulate uterine contractions during labor and delivery. Through analysis of real patient records, we propose to model uterine contraction signals by three major components: regular contractions, impulsive noise caused by fetal movements, and low amplitude noise invoked by maternal breathing and measuring apparatus. The regular contractions are modeled by an asymmetric generalized Gaussian function and least squares estimation is used to compute the parameter values of the asymmetric generalized Gaussian function based on uterine contractions of real patients. Regular contractions are detected based on thresholding and derivative analysis of uterine contractions. Impulsive noise caused by fetal movements and low amplitude noise by maternal breathing and measuring apparatus are modeled by rational polynomial functions and Perlin noise, respectively. Experiment results show the synthesized uterine contractions can mimic the real uterine contractions realistically, demonstrating the effectiveness of the proposed algorithm.
Applications of Joint Tactical Simulation Modeling
1997-12-01
NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS APPLICATIONS OF JOINT TACTICAL SIMULATION MODELING by Steve VanLandingham December 1997...SUBTITLE APPLICATIONS OF JOINT TACTICAL SIMULATION MODELING 5. FUNDING NUMBERS 6. AUTHOR(S) VanLandingham, Steve 7. PERFORMING ORGANIZATION NAME(S...release; distribution is unlimited. APPLICATIONS OF JOINT TACTICAL SIMULATION MODELING Steve VanLandingham Lieutenant, United States Navy B.S
Energy Technology Data Exchange (ETDEWEB)
Xu Song [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China); Li Zhizhong [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China)], E-mail: zzli@tsinghua.edu.cn; Song Fei; Luo Wei; Zhao Qianyi; Salvendy, Gavriel [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China)
2009-02-15
With the development of information technology, computerized emergency operating procedures (EOPs) are taking the place of paper-based ones. However, ergonomics issues of computerized EOPs have not been studied adequately since the industrial practice is quite limited yet. This study examined the influence of step complexity and presentation style of EOPs on step performance. A simulated computerized EOP system was developed in two presentation styles: Style A: one- and two-dimensional flowcharts combination; Style B: two-dimensional flowchart and success logic tree combination. Step complexity was quantified by a complexity measure model based on an entropy concept. Forty subjects participated in the experiment of EOP execution using the simulated system. The results of data analysis on the experiment data indicate that step complexity and presentation style could significantly influence step performance (both step error rate and operation time). Regression models were also developed. The regression analysis results imply that operation time of a step could be well predicted by step complexity while step error rate could only partly predicted by it. The result of a questionnaire investigation implies that step error rate was influenced not only by the operation task itself but also by other human factors. These findings may be useful for the design and assessment of computerized EOPs.
Benchmark simulation models, quo vadis?
DEFF Research Database (Denmark)
Jeppsson, U.; Alex, J; Batstone, D. J.
2013-01-01
As the work of the IWA Task Group on Benchmarking of Control Strategies for wastewater treatment plants (WWTPs) is coming to an end, it is essential to disseminate the knowledge gained. For this reason, all authors of the IWA Scientific and Technical Report on benchmarking have come together to p...... already being done within the context of the benchmarking simulation models (BSMs) or applicable work in the wider literature. Of key importance is increasing capability, usability and transparency of the BSM package while avoiding unnecessary complexity. © IWA Publishing 2013....... and spatial extension, process modifications within the WWTP, the realism of models, control strategy extensions and the potential for new evaluation tools within the existing benchmark system. We find that there are major opportunities for application within all of these areas, either from existing work...
SWEEPOP a simulation model for Target Simulation Mode minesweeping
Keus, H.E.; Beckers, A.L.D.; Cleophas, P.L.H.
2005-01-01
SWEEPOP is a flexible model that simulates the physical interaction between objects in a maritime underwater environment. The model was built to analyse the deployment and the performance of a Target Simulation Mode (TSM) minesweeping system for the Royal Netherlands Navy (RNLN) and to support its p
Chan, Jeanie; Whelan, Errol
1988-01-01
Discusses the development of a computerized high school library which uses CD-ROM optical storage systems. Describes hardware and software, setting up the system, preparing the online catalog, teaching information retrieval skills, and project evaluation. Notes prices of CD-ROM disks and equipment purchased. 4 references. (SV)
Davies, Phil
2000-01-01
Describes the introduction of a computerized peer assessment system as part of an undergraduate module in computer studies in the United Kingdom. Analyzes student responses to modification of the tutor-student relationship to a student-student relationship for assessment purposes, discusses plagiarism and the Web, and investigates effects on…
Computerized Drug Information Services
And Others; Smith, Daniel R.
1972-01-01
To compare computerized services in chemistry, pharmacology, toxicology, and clinical medicine of pharmaceutical interest, equivalent profiles were run on magnetic tape files of CA-Condensates," CBAC," Excerpta Medica," MEDLARS" and Ringdoc." The results are tabulated for overlap of services, relative speed of citing references, and unique…
Techniques and Simulation Models in Risk Management
Mirela GHEORGHE
2012-01-01
In the present paper, the scientific approach of the research starts from the theoretical framework of the simulation concept and then continues in the setting of the practical reality, thus providing simulation models for a broad range of inherent risks specific to any organization and simulation of those models, using the informatics instrument @Risk (Palisade). The reason behind this research lies in the need for simulation models that will allow the person in charge with decision taking i...
Bridging experiments, models and simulations
DEFF Research Database (Denmark)
Carusi, Annamaria; Burrage, Kevin; Rodríguez, Blanca
2012-01-01
Computational models in physiology often integrate functional and structural information from a large range of spatiotemporal scales from the ionic to the whole organ level. Their sophistication raises both expectations and skepticism concerning how computational methods can improve our understan...... that contributes to defining the specific aspects of cardiac electrophysiology the MSE system targets, rather than being only an external test, and that this is driven by advances in experimental and computational methods and the combination of both....... of biovariability; 2) testing and developing robust techniques and tools as a prerequisite to conducting physiological investigations; 3) defining and adopting standards to facilitate the interoperability of experiments, models, and simulations; 4) and understanding physiological validation as an iterative process...... understanding of living organisms and also how they can reduce, replace, and refine animal experiments. A fundamental requirement to fulfill these expectations and achieve the full potential of computational physiology is a clear understanding of what models represent and how they can be validated. The present...
Huang, L. C. P.; Cook, R. A.
1973-01-01
Models utilizing various sub-sets of the six degrees of freedom are used in trajectory simulation. A 3-D model with only linear degrees of freedom is especially attractive, since the coefficients for the angular degrees of freedom are the most difficult to determine and the angular equations are the most time consuming for the computer to evaluate. A computer program is developed that uses three separate subsections to predict trajectories. A launch rail subsection is used until the rocket has left its launcher. The program then switches to a special 3-D section which computes motions in two linear and one angular degrees of freedom. When the rocket trims out, the program switches to the standard, three linear degrees of freedom model.
Distributed simulation a model driven engineering approach
Topçu, Okan; Oğuztüzün, Halit; Yilmaz, Levent
2016-01-01
Backed by substantive case studies, the novel approach to software engineering for distributed simulation outlined in this text demonstrates the potent synergies between model-driven techniques, simulation, intelligent agents, and computer systems development.
Benchmark simulation models, quo vadis?
Jeppsson, U; Alex, J; Batstone, D J; Benedetti, L; Comas, J; Copp, J B; Corominas, L; Flores-Alsina, X; Gernaey, K V; Nopens, I; Pons, M-N; Rodríguez-Roda, I; Rosen, C; Steyer, J-P; Vanrolleghem, P A; Volcke, E I P; Vrecko, D
2013-01-01
As the work of the IWA Task Group on Benchmarking of Control Strategies for wastewater treatment plants (WWTPs) is coming to an end, it is essential to disseminate the knowledge gained. For this reason, all authors of the IWA Scientific and Technical Report on benchmarking have come together to provide their insights, highlighting areas where knowledge may still be deficient and where new opportunities are emerging, and to propose potential avenues for future development and application of the general benchmarking framework and its associated tools. The paper focuses on the topics of temporal and spatial extension, process modifications within the WWTP, the realism of models, control strategy extensions and the potential for new evaluation tools within the existing benchmark system. We find that there are major opportunities for application within all of these areas, either from existing work already being done within the context of the benchmarking simulation models (BSMs) or applicable work in the wider literature. Of key importance is increasing capability, usability and transparency of the BSM package while avoiding unnecessary complexity.
Energy Technology Data Exchange (ETDEWEB)
Pla, C.; Podgorsak, E.B.
A computerized thermoluminescent (TL) readout technique is presented which considerably improves the precision of dose readout and facilitates the dose information management and storage. The technique is relatively simple and it involves an interface between a commercially available thermoluminescent dosimetry (TLD) analyzer and a minicomputer. Curve fitting, subtraction of unwanted thermogram peaks, background subtraction, studies of TL decay kinetics, and storage of large number of measured TL data are easily performed with the technique.
Computerizing clinical practice guidelines
DEFF Research Database (Denmark)
Lyng, Karen Marie
It is well described that hospitals have problems with sustaining high quality of care and expedient introduction of new medical knowledge. Clinical practice guidelines (CPGs) have been promoted as a remedy to deal with these problems. It is, however, also well described that application and comp......It is well described that hospitals have problems with sustaining high quality of care and expedient introduction of new medical knowledge. Clinical practice guidelines (CPGs) have been promoted as a remedy to deal with these problems. It is, however, also well described that application...... and compliance with CPGs in most areas of clinical practice are deficient. Computerization of CPGs has been brought forward as a method to disseminate and to support application of CPGs. Until now, CPG-computerization has focused on development of formal expressions of CPGs. The developed systems have, however......, not gained any extensive application in clinical practice. The basic assumption in this thesis is that the scanty penetration is due to an inappropriate design process when designing computerized CPGs for clinical work practice. This thesis examines the application of guidance within areas where CPG...
Marques, Nicole Ribeiro; Whitehead, William E; Kallu, Upendar R; Kinsky, Michael P; Funston, Joe S; Wassar, Taoufik; Khan, Muzna N; Milosch, Mindy; Jupiter, Daniel; Grigoriadis, Karolos; Kramer, George C
2017-07-01
Vasopressors provide a rapid and effective approach to correct hypotension in the perioperative setting. Our group developed a closed-loop control (CLC) system that titrates phenylephrine (PHP) based on the mean arterial pressure (MAP) during general anesthesia. As a means of evaluating system competence, we compared the performance of the automated CLC with physicians. We hypothesized that our CLC algorithm more effectively maintains blood pressure at a specified target with less blood pressure variability and reduces the dose of PHP required. In a crossover study design, 6 swine under general anesthesia were subjected to a normovolemic hypotensive challenge induced by sodium nitroprusside. The physicians (MD) manually changed the PHP infusion rate, and the CLC system performed this task autonomously, adjusted every 3 seconds to achieve a predetermined MAP. The CLC maintained MAP within 5 mm Hg of the target for (mean ± standard deviation) 93.5% ± 3.9% of the time versus 72.4% ± 26.8% for the MD treatment (P = .054). The mean (standard deviation) percentage of time that the CLC and MD interventions were above target range was 2.1% ± 3.3% and 25.8% ± 27.4% (P = .06), respectively. Control statistics, performance error, median performance error, and median absolute performance error were not different between CLC and MD interventions. PHP infusion rate adjustments by the physician were performed 12 to 80 times in individual studies over a 60-minute period. The total dose of PHP used was not different between the 2 interventions. The CLC system performed as well as an anesthesiologist totally focused on MAP control by infusing PHP. Computerized CLC infusion of PHP provided tight blood pressure control under conditions of experimental vasodilation.
Structured building model reduction toward parallel simulation
Energy Technology Data Exchange (ETDEWEB)
Dobbs, Justin R. [Cornell University; Hencey, Brondon M. [Cornell University
2013-08-26
Building energy model reduction exchanges accuracy for improved simulation speed by reducing the number of dynamical equations. Parallel computing aims to improve simulation times without loss of accuracy but is poorly utilized by contemporary simulators and is inherently limited by inter-processor communication. This paper bridges these disparate techniques to implement efficient parallel building thermal simulation. We begin with a survey of three structured reduction approaches that compares their performance to a leading unstructured method. We then use structured model reduction to find thermal clusters in the building energy model and allocate processing resources. Experimental results demonstrate faster simulation and low error without any interprocessor communication.
Simulation and Modeling Methodologies, Technologies and Applications
Filipe, Joaquim; Kacprzyk, Janusz; Pina, Nuno
2014-01-01
This book includes extended and revised versions of a set of selected papers from the 2012 International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH 2012) which was sponsored by the Institute for Systems and Technologies of Information, Control and Communication (INSTICC) and held in Rome, Italy. SIMULTECH 2012 was technically co-sponsored by the Society for Modeling & Simulation International (SCS), GDR I3, Lionphant Simulation, Simulation Team and IFIP and held in cooperation with AIS Special Interest Group of Modeling and Simulation (AIS SIGMAS) and the Movimento Italiano Modellazione e Simulazione (MIMOS).
An introduction to enterprise modeling and simulation
Energy Technology Data Exchange (ETDEWEB)
Ostic, J.K.; Cannon, C.E. [Los Alamos National Lab., NM (United States). Technology Modeling and Analysis Group
1996-09-01
As part of an ongoing effort to continuously improve productivity, quality, and efficiency of both industry and Department of Energy enterprises, Los Alamos National Laboratory is investigating various manufacturing and business enterprise simulation methods. A number of enterprise simulation software models are being developed to enable engineering analysis of enterprise activities. In this document the authors define the scope of enterprise modeling and simulation efforts, and review recent work in enterprise simulation at Los Alamos National Laboratory as well as at other industrial, academic, and research institutions. References of enterprise modeling and simulation methods and a glossary of enterprise-related terms are provided.
A physiological production model for cacao : results of model simulations
Zuidema, P.A.; Leffelaar, P.A.
2002-01-01
CASE2 is a physiological model for cocoa (Theobroma cacao L.) growth and yield. This report introduces the CAcao Simulation Engine for water-limited production in a non-technical way and presents simulation results obtained with the model.
A physiological production model for cacao : results of model simulations
Zuidema, P.A.; Leffelaar, P.A.
2002-01-01
CASE2 is a physiological model for cocoa (Theobroma cacao L.) growth and yield. This report introduces the CAcao Simulation Engine for water-limited production in a non-technical way and presents simulation results obtained with the model.
Simulation modeling and analysis with Arena
Altiok, Tayfur
2007-01-01
Simulation Modeling and Analysis with Arena is a highly readable textbook which treats the essentials of the Monte Carlo discrete-event simulation methodology, and does so in the context of a popular Arena simulation environment. It treats simulation modeling as an in-vitro laboratory that facilitates the understanding of complex systems and experimentation with what-if scenarios in order to estimate their performance metrics. The book contains chapters on the simulation modeling methodology and the underpinnings of discrete-event systems, as well as the relevant underlying probability, statistics, stochastic processes, input analysis, model validation and output analysis. All simulation-related concepts are illustrated in numerous Arena examples, encompassing production lines, manufacturing and inventory systems, transportation systems, and computer information systems in networked settings.· Introduces the concept of discrete event Monte Carlo simulation, the most commonly used methodology for modeli...
Nonsmooth Modeling and Simulation for Switched Circuits
Acary, Vincent; Brogliato, Bernard
2011-01-01
"Nonsmooth Modeling and Simulation for Switched Circuits" concerns the modeling and the numerical simulation of switched circuits with the nonsmooth dynamical systems (NSDS) approach, using piecewise-linear and multivalued models of electronic devices like diodes, transistors, switches. Numerous examples (ranging from introductory academic circuits to various types of power converters) are analyzed and many simulation results obtained with the INRIA open-source SICONOS software package are presented. Comparisons with SPICE and hybrid methods demonstrate the power of the NSDS approach
Juno model rheometry and simulation
Sampl, Manfred; Macher, Wolfgang; Oswald, Thomas; Plettemeier, Dirk; Rucker, Helmut O.; Kurth, William S.
2016-10-01
The experiment Waves aboard the Juno spacecraft, which will arrive at its target planet Jupiter in 2016, was devised to study the plasma and radio waves of the Jovian magnetosphere. We analyzed the Waves antennas, which consist of two nonparallel monopoles operated as a dipole. For this investigation we applied two independent methods: the experimental technique, rheometry, which is based on a downscaled model of the spacecraft to measure the antenna properties in an electrolytic tank and numerical simulations, based on commercial computer codes, from which the quantities of interest (antenna impedances and effective length vectors) are calculated. In this article we focus on the results for the low-frequency range up to about 4 MHz, where the antenna system is in the quasi-static regime. Our findings show that there is a significant deviation of the effective length vectors from the physical monopole directions, caused by the presence of the conducting spacecraft body. The effective axes of the antenna monopoles are offset from the mechanical axes by more than 30°, and effective lengths show a reduction to about 60% of the antenna rod lengths. The antennas' mutual capacitances are small compared to the self-capacitances, and the latter are almost the same for the two monopoles. The overall performance of the antennas in dipole configuration is very stable throughout the frequency range up to about 4-5 MHz and therefore can be regarded as the upper frequency bound below which the presented quasi-static results are applicable.
Network Modeling and Simulation A Practical Perspective
Guizani, Mohsen; Khan, Bilal
2010-01-01
Network Modeling and Simulation is a practical guide to using modeling and simulation to solve real-life problems. The authors give a comprehensive exposition of the core concepts in modeling and simulation, and then systematically address the many practical considerations faced by developers in modeling complex large-scale systems. The authors provide examples from computer and telecommunication networks and use these to illustrate the process of mapping generic simulation concepts to domain-specific problems in different industries and disciplines. Key features: Provides the tools and strate
VHDL simulation with access to transistor models
Gibson, J.
1991-01-01
Hardware description languages such as VHDL have evolved to aid in the design of systems with large numbers of elements and a wide range of electronic and logical abstractions. For high performance circuits, behavioral models may not be able to efficiently include enough detail to give designers confidence in a simulation's accuracy. One option is to provide a link between the VHDL environment and a transistor level simulation environment. The coupling of the Vantage Analysis Systems VHDL simulator and the NOVA simulator provides the combination of VHDL modeling and transistor modeling.
Computerized procedures system
Lipner, Melvin H.; Mundy, Roger A.; Franusich, Michael D.
2010-10-12
An online data driven computerized procedures system that guides an operator through a complex process facility's operating procedures. The system monitors plant data, processes the data and then, based upon this processing, presents the status of the current procedure step and/or substep to the operator. The system supports multiple users and a single procedure definition supports several interface formats that can be tailored to the individual user. Layered security controls access privileges and revisions are version controlled. The procedures run on a server that is platform independent of the user workstations that the server interfaces with and the user interface supports diverse procedural views.
Sang, Nguyen Duy; Van Hung, Nguyen; Van Hung, Tran; Hien, Nguyen Quoc
2017-03-01
The kinetic parameters of thermoluminescence (TL) glow peaks of chilli powder irradiated by gamma rays with the different doses of 0, 4 and 8 kGy have been calculated and estimate by computerized glow curve deconvolution (CGCD) method and the R package tgcd by using the TL glow curve data. The kinetic parameters of TL glow peaks (i.e. activation energies (E), order of kinetics (b), trapping and recombination probability coefficients (R) and frequency factors (s)) are fitted by modeled general-orders of kinetics (GOK) and one trap-one recombination (OTOR). The kinetic parameters of the chilli powder are different toward the difference of the sample time-storage, radiation doses, GOK model and OTOR one. The samples spending the shorter period of storage time have the smaller the kinetic parameters values than the samples spending the longer period of storage. The results obtained as comparing the kinetic parameters values of the three samples show that the value of non-irradiated samples are lowest whereas the 4 kGy irradiated-samples' value are greater than the 8 kGy irradiated-samples' one time.
Modeling and Simulation of Low Voltage Arcs
Ghezzi, L.; Balestrero, A.
2010-01-01
Modeling and Simulation of Low Voltage Arcs is an attempt to improve the physical understanding, mathematical modeling and numerical simulation of the electric arcs that are found during current interruptions in low voltage circuit breakers. An empirical description is gained by refined electrical
Modeling and Simulation of Low Voltage Arcs
Ghezzi, L.; Balestrero, A.
2010-01-01
Modeling and Simulation of Low Voltage Arcs is an attempt to improve the physical understanding, mathematical modeling and numerical simulation of the electric arcs that are found during current interruptions in low voltage circuit breakers. An empirical description is gained by refined electrical m
Whole-building Hygrothermal Simulation Model
DEFF Research Database (Denmark)
Rode, Carsten; Grau, Karl
2003-01-01
An existing integrated simulation tool for dynamic thermal simulation of building was extended with a transient model for moisture release and uptake in building materials. Validation of the new model was begun with comparison against measurements in an outdoor test cell furnished with single mat...
Whole-building Hygrothermal Simulation Model
DEFF Research Database (Denmark)
Rode, Carsten; Grau, Karl
2003-01-01
An existing integrated simulation tool for dynamic thermal simulation of building was extended with a transient model for moisture release and uptake in building materials. Validation of the new model was begun with comparison against measurements in an outdoor test cell furnished with single...... materials. Almost quasi-steady, cyclic experiments were used to compare the indoor humidity variation and the numerical results of the integrated simulation tool with the new moisture model. Except for the case with chipboard as furnishing, the predictions of indoor humidity with the detailed model were...
Simulation model of metallurgical production management
Directory of Open Access Journals (Sweden)
P. Šnapka
2013-07-01
Full Text Available This article is focused to the problems of the metallurgical production process intensification. The aim is the explaining of simulation model which presents metallurgical production management system adequated to new requirements. The knowledge of a dynamic behavior and features of metallurgical production system and its management are needed to this model creation. Characteristics which determine the dynamics of metallurgical production process are characterized. Simulation model is structured as functional blocks and their linkages with regard to organizational and temporal hierarchy of their actions. The creation of presented simulation model is based on theoretical findings of regulation, hierarchical systems and optimization.
Simulation modeling for the health care manager.
Kennedy, Michael H
2009-01-01
This article addresses the use of simulation software to solve administrative problems faced by health care managers. Spreadsheet add-ins, process simulation software, and discrete event simulation software are available at a range of costs and complexity. All use the Monte Carlo method to realistically integrate probability distributions into models of the health care environment. Problems typically addressed by health care simulation modeling are facility planning, resource allocation, staffing, patient flow and wait time, routing and transportation, supply chain management, and process improvement.
Warehouse Simulation Through Model Configuration
Verriet, J.H.; Hamberg, R.; Caarls, J.; Wijngaarden, B. van
2013-01-01
The pre-build development of warehouse systems leads from a specific customer request to a specific customer quotation. This involves a process of configuring a warehouse system using a sequence of steps that contain increasingly more details. Simulation is a helpful tool in analyzing warehouse desi
Modeling and Simulation of Matrix Converter
DEFF Research Database (Denmark)
Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede
2005-01-01
This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...
Quantum simulation of the t- J model
Yamaguchi, Fumiko; Yamamoto, Yoshihisa
2002-12-01
Computer simulation of a many-particle quantum system is bound to reach the inevitable limits of its ability as the system size increases. The primary reason for this is that the memory size used in a classical simulator grows polynomially whereas the Hilbert space of the quantum system does so exponentially. Replacing the classical simulator by a quantum simulator would be an effective method of surmounting this obstacle. The prevailing techniques for simulating quantum systems on a quantum computer have been developed for purposes of computing numerical algorithms designed to obtain approximate physical quantities of interest. The method suggested here requires no numerical algorithms; it is a direct isomorphic translation between a quantum simulator and the quantum system to be simulated. In the quantum simulator, physical parameters of the system, which are the fixed parameters of the simulated quantum system, are under the control of the experimenter. A method of simulating a model for high-temperature superconducting oxides, the t- J model, by optical control, as an example of such a quantum simulation, is presented.
CAUSA - An Environment For Modeling And Simulation
Dilger, Werner; Moeller, Juergen
1989-03-01
CAUSA is an environment for modeling and simulation of dynamic systems on a quantitative level. The environment provides a conceptual framework including primitives like objects, processes and causal dependencies which allow the modeling of a broad class of complex systems. The facility of simulation allows the quantitative and qualitative inspection and empirical investigation of the behavior of the modeled system. CAUSA is implemented in Knowledge-Craft and runs on a Symbolics 3640.
Modeling and Simulation of Matrix Converter
DEFF Research Database (Denmark)
Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede
2005-01-01
This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...... in details. The results of simulations developed for different researches reveal that different mdel may be suitable for different purpose, thus the model should be chosen different carefully. Some details and tricks in modeling are also introduced which give a reference for further research....
Simulation-based Manufacturing System Modeling
Institute of Scientific and Technical Information of China (English)
卫东; 金烨; 范秀敏; 严隽琪
2003-01-01
In recent years, computer simulation appears to be very advantageous technique for researching the resource-constrained manufacturing system. This paper presents an object-oriented simulation modeling method, which combines the merits of traditional methods such as IDEF0 and Petri Net. In this paper, a four-layer-one-angel hierarchical modeling framework based on OOP is defined. And the modeling description of these layers is expounded, such as: hybrid production control modeling and human resource dispatch modeling. To validate the modeling method, a case study of an auto-product line in a motor manufacturing company has been carried out.
Multiscale Model Approach for Magnetization Dynamics Simulations
De Lucia, Andrea; Tretiakov, Oleg A; Kläui, Mathias
2016-01-01
Simulations of magnetization dynamics in a multiscale environment enable rapid evaluation of the Landau-Lifshitz-Gilbert equation in a mesoscopic sample with nanoscopic accuracy in areas where such accuracy is required. We have developed a multiscale magnetization dynamics simulation approach that can be applied to large systems with spin structures that vary locally on small length scales. To implement this, the conventional micromagnetic simulation framework has been expanded to include a multiscale solving routine. The software selectively simulates different regions of a ferromagnetic sample according to the spin structures located within in order to employ a suitable discretization and use either a micromagnetic or an atomistic model. To demonstrate the validity of the multiscale approach, we simulate the spin wave transmission across the regions simulated with the two different models and different discretizations. We find that the interface between the regions is fully transparent for spin waves with f...
Systematic modelling and simulation of refrigeration systems
DEFF Research Database (Denmark)
Rasmussen, Bjarne D.; Jakobsen, Arne
1998-01-01
The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose of the s......The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose...... of the simulation, to select appropriate component models and to set up the equations in a well-arranged way. In this paper the outline of such a method is proposed and examples showing the use of this method for simulation of refrigeration systems are given....
Software-Engineering Process Simulation (SEPS) model
Lin, C. Y.; Abdel-Hamid, T.; Sherif, J. S.
1992-01-01
The Software Engineering Process Simulation (SEPS) model is described which was developed at JPL. SEPS is a dynamic simulation model of the software project development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life cycle development activities and management decision making processes. The model is designed to be a planning tool to examine tradeoffs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmodern assessments.
Systematic modelling and simulation of refrigeration systems
DEFF Research Database (Denmark)
Rasmussen, Bjarne D.; Jakobsen, Arne
1998-01-01
The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose...... of the simulation, to select appropriate component models and to set up the equations in a well-arranged way. In this paper the outline of such a method is proposed and examples showing the use of this method for simulation of refrigeration systems are given....
HVDC System Characteristics and Simulation Models
Energy Technology Data Exchange (ETDEWEB)
Moon, S.I.; Han, B.M.; Jang, G.S. [Electric Enginnering and Science Research Institute, Seoul (Korea)
2001-07-01
This report deals with the AC-DC power system simulation method by PSS/E and EUROSTAG for the development of a strategy for the reliable operation of the Cheju-Haenam interconnected system. The simulation using both programs is performed to analyze HVDC simulation models. In addition, the control characteristics of the Cheju-Haenam HVDC system as well as Cheju AC system characteristics are described in this work. (author). 104 figs., 8 tabs.
Directory of Open Access Journals (Sweden)
Schellenberger Patricia
2011-02-01
Full Text Available Abstract Background It is well known that the information requirements necessary to safely treat children with therapeutic medications cannot be met with the same approaches used in adults. Over a 1-year period, Duke University Hospital engaged in the challenging task of enhancing an established computerized provider order entry (CPOE system to address the unique medication dosing needs of pediatric patients. Methods An advanced dosing model (ADM was designed to interact with our existing CPOE application to provide decision support enabling complex pediatric dose calculations based on chronological age, gestational age, weight, care area in the hospital, indication, and level of renal impairment. Given that weight is a critical component of medication dosing that may change over time, alerting logic was added to guard against erroneous entry or outdated weight information. Results Pediatric CPOE was deployed in a staggered fashion across 6 care areas over a 14-month period. Safeguards to prevent miskeyed values became important in allowing providers the flexibility to override the ADM logic if desired. Methods to guard against over- and under-dosing were added. The modular nature of our model allows us to easily add new dosing scenarios for specialized populations as the pediatric population and formulary change over time. Conclusions The medical needs of pediatric patients vary greatly from those of adults, and the information systems that support those needs require tailored approaches to design and implementation. When a single CPOE system is used for both adults and pediatrics, safeguards such as redirection and suppression must be used to protect children from inappropriate adult medication dosing content. Unlike other pediatric dosing systems, our model provides active dosing assistance and dosing process management, not just static dosing advice.
Simulation modeling and analysis with Arena
Energy Technology Data Exchange (ETDEWEB)
Tayfur Altiok; Benjamin Melamed [Rutgers University, NJ (United States). Department of Industrial and Systems Engineering
2007-06-15
The textbook which treats the essentials of the Monte Carlo discrete-event simulation methodology, and does so in the context of a popular Arena simulation environment. It treats simulation modeling as an in-vitro laboratory that facilitates the understanding of complex systems and experimentation with what-if scenarios in order to estimate their performance metrics. The book contains chapters on the simulation modeling methodology and the underpinnings of discrete-event systems, as well as the relevant underlying probability, statistics, stochastic processes, input analysis, model validation and output analysis. All simulation-related concepts are illustrated in numerous Arena examples, encompassing production lines, manufacturing and inventory systems, transportation systems, and computer information systems in networked settings. Chapter 13.3.3 is on coal loading operations on barges/tugboats.
Rabin, J M; McNett, J; Badlani, G H
1993-01-01
An electronic, computerized voiding diary, "Compu-Void" (patent pending) was developed in order to simplify, augment, and automate patients' recording of bladder symptomatology. A voiding diary as a tool has the potential to provide essential information for a more complete diagnostic and therefore therapeutic picture for each patient. Two major problems with the standard written voiding diary have been a lack of patient compliance and the limited amount of information it garners. Twenty-five women with various types of voiding dysfunctions were compared to twenty-five age and parity-matched control women in order to determine patient preferences of the Compu-Void when compared to the standard written voiding diary, compliance with each method, and amount and quality of information obtained with each method. Over 90% of subjects and over 70% of control group patients preferred the Compu-Void over the written diary (P Compu-Void exceeded that obtained with the written method.
Computerizing natural history collections.
Sunderland, Mary E
2013-09-01
Computers are ubiquitous in the life sciences and are associated with many of the practical and conceptual changes that characterize biology's twentieth-century transformation. Yet comparatively little has been written about how scientists use computers. Despite this relative lack of scholarly attention, the claim that computers revolutionized the life sciences by making the impossible possible is widespread, and relatively unchallenged. How did the introduction of computers into research programs shape scientific practice? The Museum of Vertebrate Zoology (MVZ) at the University of California, Berkeley provides a tractable way into this under-examined question because it is possible to follow the computerization of data in the context of long-term research programs.
Computerizing clinical practice guidelines
DEFF Research Database (Denmark)
Lyng, Karen Marie
. The analysis focuses on the emergence of general clinical work practice demands on guidance • An analysis of guidance demands from clinical work practice and business strategy, focusing on implications for the design of computerised CPGs. In my research, I have applied observation studies, interviews...... is comprised by fieldwork in three oncology departments and a case study of advanced life support. Although close to all patients within oncology are treated according to a CPG, I found limited application of physical CPGs and web-based CPG portals. However, I found comprehensive application of activity...... feasible • Designed in a way that provides room for local adaptations of guidance • Designed with focus on specific business strategic aims Further, based on my findings, I will suggest that design of computerized CPGs should be based on: 1) scrutinization of the clinical work practice, 2) articulation...
Object Oriented Modelling and Dynamical Simulation
DEFF Research Database (Denmark)
Wagner, Falko Jens; Poulsen, Mikael Zebbelin
1998-01-01
This report with appendix describes the work done in master project at DTU.The goal of the project was to develop a concept for simulation of dynamical systems based on object oriented methods.The result was a library of C++-classes, for use when both building componentbased models and when...... onduction simulation experiments....
Modeling and simulation for RF system design
Frevert, Ronny; Jancke, Roland; Knöchel, Uwe; Schwarz, Peter; Kakerow, Ralf; Darianian, Mohsen
2005-01-01
Focusing on RF specific modeling and simulation methods, and system and circuit level descriptions, this work contains application-oriented training material. Accompanied by a CD- ROM, it combines the presentation of a mixed-signal design flow, an introduction into VHDL-AMS and Verilog-A, and the application of commercially available simulators.
Siegfried, Robert
2014-01-01
Robert Siegfried presents a framework for efficient agent-based modeling and simulation of complex systems. He compares different approaches for describing structure and dynamics of agent-based models in detail. Based on this evaluation the author introduces the "General Reference Model for Agent-based Modeling and Simulation" (GRAMS). Furthermore he presents parallel and distributed simulation approaches for execution of agent-based models -from small scale to very large scale. The author shows how agent-based models may be executed by different simulation engines that utilize underlying hard
Nemeth, A.A.; Hulscher, S.J.M.H.; Damme, van R.M.J.
2003-01-01
Sand waves form a prominent regular pattern in the offshore seabeds of sandy shallow seas. A two dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of these sand waves has been developed. The model contains the 2DV shallow water equations, with a free water su
Modelling Reactive and Proactive Behaviour in Simulation
Majid, Mazlina Abdul; Aickelin, Uwe
2010-01-01
This research investigated the simulation model behaviour of a traditional and combined discrete event as well as agent based simulation models when modelling human reactive and proactive behaviour in human centric complex systems. A departmental store was chosen as human centric complex case study where the operation system of a fitting room in WomensWear department was investigated. We have looked at ways to determine the efficiency of new management policies for the fitting room operation through simulating the reactive and proactive behaviour of staff towards customers. Once development of the simulation models and their verification had been done, we carried out a validation experiment in the form of a sensitivity analysis. Subsequently, we executed a statistical analysis where the mixed reactive and proactive behaviour experimental results were compared with some reactive experimental results from previously published works. Generally, this case study discovered that simple proactive individual behaviou...
Challenges in SysML Model Simulation
Directory of Open Access Journals (Sweden)
Mara Nikolaidou
2016-07-01
Full Text Available Systems Modeling Language (SysML is a standard proposed by the OMG for systems-of-systems (SoS modeling and engineering. To this end, it provides the means to depict SoS components and their behavior in a hierarchical, multi-layer fashion, facilitating alternative engineering activities, such as system design. To explore the performance of SysML, simulation is one of the preferred methods. There are many efforts targeting simulation code generation from SysML models. Numerous simulation methodologies and tools are employed, while different SysML diagrams are utilized. Nevertheless, this process is not standardized, although most of current approaches tend to follow the same steps, even if they employ different tools. The scope of this paper is to provide a comprehensive understanding of the similarities and differences of existing approaches and identify current challenges in fully automating SysML models simulation process.
SIMULATION MODELING SLOW SPATIALLY HETER- OGENEOUS COAGULATION
Directory of Open Access Journals (Sweden)
P. A. Zdorovtsev
2013-01-01
Full Text Available A new model of spatially inhomogeneous coagulation, i.e. formation of larger clusters by joint interaction of smaller ones, is under study. The results of simulation are compared with known analytical and numerical solutions.
A Heuristic Force Model for Haptic Simulation of Nasogastric Tube Insertion Using Fuzzy Logic.
Choi, Kup-Sze; He, Xue-Jian; Chiang, Vico C L; Deng, Zhaohong; Qin, Jing
2016-01-01
Nasogastric tube (NGT) placement is an essential clinical skill. The training is conventionally performed on rubber mannequins albeit practical limitations. Computer simulation with haptic feedback can potentially offer a more realistic and accessible training method. However, the complex interactions between the tube and the nasogastric passage make it difficult to model the haptic feedback during NGT placement. In this paper, a fuzzy-logic-based approach is proposed to directly transfer the experience of clinicians in NGT placement into the simulation system. Based on their perception of the varying tactile sensation and the conditions during NGT placement, the membership functions and fuzzy rules are defined to develop the force model. Forces created using the model are then combined with friction forces to drive the haptic device and render the insertion forces in real time. A prototype simulator is developed based on the proposed force model and the implementation details are presented. The usability of the prototype is also evaluated by clinical teachers. The proposed methodology has the potential for developing computerized NGT placement training methods for clinical education. It is also applicable for simulation systems involving complicated force interactions or computation-expensive models.
Theory, modeling, and simulation annual report, 1992
Energy Technology Data Exchange (ETDEWEB)
1993-05-01
This report briefly discusses research on the following topics: development of electronic structure methods; modeling molecular processes in clusters; modeling molecular processes in solution; modeling molecular processes in separations chemistry; modeling interfacial molecular processes; modeling molecular processes in the atmosphere; methods for periodic calculations on solids; chemistry and physics of minerals; graphical user interfaces for computational chemistry codes; visualization and analysis of molecular simulations; integrated computational chemistry environment; and benchmark computations.
Collins, Michael G; Juvina, Ion; Gluck, Kevin A
2016-01-01
When playing games of strategic interaction, such as iterated Prisoner's Dilemma and iterated Chicken Game, people exhibit specific within-game learning (e.g., learning a game's optimal outcome) as well as transfer of learning between games (e.g., a game's optimal outcome occurring at a higher proportion when played after another game). The reciprocal trust players develop during the first game is thought to mediate transfer of learning effects. Recently, a computational cognitive model using a novel trust mechanism has been shown to account for human behavior in both games, including the transfer between games. We present the results of a study in which we evaluate the model's a priori predictions of human learning and transfer in 16 different conditions. The model's predictive validity is compared against five model variants that lacked a trust mechanism. The results suggest that a trust mechanism is necessary to explain human behavior across multiple conditions, even when a human plays against a non-human agent. The addition of a trust mechanism to the other learning mechanisms within the cognitive architecture, such as sequence learning, instance-based learning, and utility learning, leads to better prediction of the empirical data. It is argued that computational cognitive modeling is a useful tool for studying trust development, calibration, and repair.
Application of Chebyshev Polynomial to simulated modeling
Institute of Scientific and Technical Information of China (English)
CHI Hai-hong; LI Dian-pu
2006-01-01
Chebyshev polynomial is widely used in many fields, and used usually as function approximation in numerical calculation. In this paper, Chebyshev polynomial expression of the propeller properties across four quadrants is given at first, then the expression of Chebyshev polynomial is transformed to ordinary polynomial for the need of simulation of propeller dynamics. On the basis of it,the dynamical models of propeller across four quadrants are given. The simulation results show the efficiency of mathematical model.
Collisionless Electrostatic Shock Modeling and Simulation
2016-10-21
Briefing Charts 3. DATES COVERED (From - To) 30 September 2016 – 21 October 2016 4. TITLE AND SUBTITLE Collisionless Electrostatic Shock Modeling and...release: distribution unlimited. PA#16490 Air Force Research Laboratory Collisionless Electrostatic Shock Modeling and Simulation Daniel W. Crews In-Space...unlimited. PA#16490 Overview • Motivation and Background • What is a Collisionless Shock Wave? • Features of the Collisionless Shock • The Shock Simulation
Energy Technology Data Exchange (ETDEWEB)
Iliadis, Georgios; Misailidou, Despina [Dept. of Radiation Oncology, ' ' Papageorgiou' ' General Hospital, Thessaloniki (Greece); Selviaridis, Panagiotis; Chatzisotiriou, Athanasios [Dept. of Neurosurgery, ' ' AHEPA' ' Hospital, Aristotle Univ. of Thessaloniki, School of Medicine (Greece); Kalogera-Fountzila, Anna [Dept. of Radiology, ' ' AHEPA' ' Hospital, Aristotle Univ. of Thessaloniki, School of Medicine (Greece); Fragkoulidi, Anna; Fountzilas, George [Dept. of Medical Oncology, ' ' Papageorgiou' ' General Hospital, Aristotle Univ. of Thessaloniki, School of Medicine (Greece); Baltas, Dimos; Tselis, Nikolaos; Zamboglou, Nikolaos [Dept. of Radiation Oncology, Klinikum Offenbach (Germany)
2009-11-15
Background and purpose: the importance of tumor volume as a prognostic factor in high-grade gliomas is highly controversial and there are numerous methods estimating this parameter. In this study, a computer-based application was used in order to assess tumor volume from hard copies and a survival analysis was conducted in order to evaluate the prognostic significance of preoperative volumetric data in patients harboring glioblastomas. Patients and methods: 50 patients suffering from glioblastoma were analyzed retrospectively. Tumor volume was determined by the various geometric models as well as by an own specialized software (Volumio). Age, performance status, type of excision, and tumor location were also included in the multivariate analysis. Results: the spheroid and rectangular models overestimated tumor volume, while the ellipsoid model offered the best approximation. Volume failed to attain any statistical significance in prognosis, while age and performance status confirmed their importance in progression-free and overall survival of patients. Conclusion: geometric models provide a rough approximation of tumor volume and should not be used, as accurate determination of size is of paramount importance in order to draw safe conclusions in oncology. Although the significance of volumetry was not disclosed, further studies are definitely required. (orig.)
Modeling of magnetic particle suspensions for simulations
Satoh, Akira
2017-01-01
The main objective of the book is to highlight the modeling of magnetic particles with different shapes and magnetic properties, to provide graduate students and young researchers information on the theoretical aspects and actual techniques for the treatment of magnetic particles in particle-based simulations. In simulation, we focus on the Monte Carlo, molecular dynamics, Brownian dynamics, lattice Boltzmann and stochastic rotation dynamics (multi-particle collision dynamics) methods. The latter two simulation methods can simulate both the particle motion and the ambient flow field simultaneously. In general, specialized knowledge can only be obtained in an effective manner under the supervision of an expert. The present book is written to play such a role for readers who wish to develop the skill of modeling magnetic particles and develop a computer simulation program using their own ability. This book is therefore a self-learning book for graduate students and young researchers. Armed with this knowledge,...
Modelling and Simulation of Wave Loads
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Thoft-Christensen, Palle
A simple model of the wave load on slender members of offshore structures is described. The wave elevation of the sea state is modelled by a stationary Gaussian process. A new procedure to simulate realizations of the wave loads is developed. The simulation method assumes that the wave particle...... velocity can be approximated by a Gaussian Markov process. Known approximate results for the first-passage density or equivalently, the distribution of the extremes of wave loads are presented and compared with rather precise simulation results. It is demonstrated that the approximate results...
Modelling and Simulation of Wave Loads
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Thoft-Christensen, Palle
1985-01-01
A simple model of the wave load on stender members of offshore structures is described . The wave elevation of the sea stateis modelled by a stationary Gaussian process. A new procedure to simulate realizations of the wave loads is developed. The simulation method assumes that the wave particle...... velocity can be approximated by a Gaussian Markov process. Known approximate results for the first passage density or equivalently, the distribution of the extremes of wave loads are presented and compared with rather precise simulation results. It is demonstrated that the approximate results...
Modeling and simulation of multiport RF switch
Energy Technology Data Exchange (ETDEWEB)
Vijay, J [Student, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India); Saha, Ivan [Scientist, Indian Space Research Organisation (ISRO) (India); Uma, G [Lecturer, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India); Umapathy, M [Assistant Professor, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India)
2006-04-01
This paper describes the modeling and simulation of 'Multi Port RF Switch' where the latching mechanism is realized with two hot arm electro thermal actuators and the switching action is realized with electrostatic actuators. It can act as single pole single thrown as well as single pole multi thrown switch. The proposed structure is modeled analytically and required parameters are simulated using MATLAB. The analytical simulation results are validated using Finite Element Analysis of the same in the COVENTORWARE software.
Modeling and simulation of discrete event systems
Choi, Byoung Kyu
2013-01-01
Computer modeling and simulation (M&S) allows engineers to study and analyze complex systems. Discrete-event system (DES)-M&S is used in modern management, industrial engineering, computer science, and the military. As computer speeds and memory capacity increase, so DES-M&S tools become more powerful and more widely used in solving real-life problems. Based on over 20 years of evolution within a classroom environment, as well as on decades-long experience in developing simulation-based solutions for high-tech industries, Modeling and Simulation of Discrete-Event Systems is the only book on
Traffic Modeling in WCDMA System Level Simulations
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Traffic modeling is a crucial element in WCDMA system level simulations. A clear understanding of the nature of traffic in the WCDMA system and subsequent selection of an appropriate random traffic model are critical to the success of the modeling enterprise. The resultant performances will evidently be of a function that our design has been well adapted to the traffic, channel and user mobility models, and these models are also accurate. In this article, our attention will be focused on modeling voice and WWW data traffic with the SBBP model and Victor model respectively.
The Future of Computerized Decision Making
2014-12-01
available in digital form -- data such as newspaper articles, video, and books -- and can be searched according to topics and keywords , or sounds and...away from using observational or model- driven data to inform their decisions. At the same time, enhancements to methods for rapidly creating, merging...themselves---and that we need automated ways of reoptimizing as these metamodels evolve over time. Causal computerized decision making: As I discuss
Directory of Open Access Journals (Sweden)
Michael Gordon Collins
2016-02-01
Full Text Available When playing games of strategic interaction, such as iterated Prisoner’s Dilemma and iterated Chicken Game, people exhibit specific within-game learning (e.g., learning a game’s optimal outcome as well as transfer of learning between games (e.g., a game’s optimal outcome occurring at a higher proportion when played after another game. The reciprocal trust players develop during the first game is thought to mediate transfer of learning effects. Recently, a computational cognitive model using a novel trust mechanism has been shown to account for human behavior in both games, including the transfer between games. We present the results of a study in which we evaluate the model’s a priori predictions of human learning and transfer in 16 different conditions. The model’s predictive validity is compared against five model variants that lacked a trust mechanism. The results suggest that a trust mechanism is necessary to explain human behavior across multiple conditions, even when a human plays against a non-human agent. The addition of a trust mechanism to the other learning mechanisms within the cognitive architecture, such as sequence learning, instance-based learning, and utility learning, leads to better prediction of the empirical data. It is argued that computational cognitive modeling is a useful tool for studying trust development, calibration, and repair.
Methods and tasks of simulation modeling of mine robot systems
Energy Technology Data Exchange (ETDEWEB)
Tailakov, O.V. (Institut Uglya SO RAN (Russian Federation))
1992-11-01
Discusses a procedure for computerized simulation of operation of a robot longwall mining system. The following aspects are analyzed: selecting a variant from among a number of structural schemes of the robot mining systems (using six types of robots for coal cutting, powered support advance, support installation, drilling, haulage and other auxiliary operations), assessment of robot loading during haulage of mine stones or coal from development workings (from mine drivage), assessment of losses caused by equipment failures, verification of algorithms used for robot control, comparative evaluations of economic efficiency of the robot mining systems. 2 refs.
Modeling and simulation of luminescence detection platforms.
Salama, Khaled; Eltoukhy, Helmy; Hassibi, Arjang; El-Gamal, Abbas
2004-06-15
Motivated by the design of an integrated CMOS-based detection platform, a simulation model for CCD and CMOS imager-based luminescence detection systems is developed. The model comprises four parts. The first portion models the process of photon flux generation from luminescence probes using ATP-based and luciferase label-based assay kinetics. An optics simulator is then used to compute the incident photon flux on the imaging plane for a given photon flux and system geometry. Subsequently, the output image is computed using a detailed imaging sensor model that accounts for photodetector spectral response, dark current, conversion gain, and various noise sources. Finally, signal processing algorithms are applied to the image to enhance detection reliability and hence increase the overall system throughput. To validate the model, simulation results are compared to experimental results obtained from a CCD-based system that was built to emulate the integrated CMOS-based platform.
SOFT MODELLING AND SIMULATION IN STRATEGY
Directory of Open Access Journals (Sweden)
Luciano Rossoni
2006-06-01
Full Text Available A certain resistance on the part of the responsible controllers for the strategy exists, in using techniques and tools of modeling and simulation. Many find them excessively complicated, already others see them as rigid and mathematical for excessively for the use of strategies in uncertain and turbulent environments. However, some interpretative boarding that take care of, in part exist, the necessities of these borrowers of decision. The objective of this work is to demonstrate of a clear and simple form, some of the most powerful boarding, methodologies and interpretative tools (soft of modeling and simulation in the business-oriented area of strategy. We will define initially, what they are on models, simulation and some aspects to the modeling and simulation in the strategy area. Later we will see some boarding of modeling soft, that they see the modeling process much more of that simply a mechanical process, therefore, as seen for Simon, the human beings rationally are limited and its decisions are influenced by a series of questions of subjective character, related to the way where it is inserted. Keywords: strategy, modeling and simulation, soft systems methodology, cognitive map, systems dynamics.
Modeling and Simulation of Hydraulic Engine Mounts
Institute of Scientific and Technical Information of China (English)
DUAN Shanzhong; Marshall McNea
2012-01-01
Hydraulic engine mounts are widely used in automotive powertrains for vibration isolation.A lumped mechanical parameter model is a traditional approach to model and simulate such mounts.This paper presents a dynamical model of a passive hydraulic engine mount with a double-chamber,an inertia track,a decoupler,and a plunger.The model is developed based on analogy between electrical systems and mechanical-hydraulic systems.The model is established to capture both low and high frequency dynatmic behaviors of the hydraulic mount.The model will be further used to find the approximate pulse responses of the mounts in terms of the force transmission and top chamber pressure.The close form solution from the simplifiod linear model may provide some insight into the highly nonlinear behavior of the mounts.Based on the model,computer simulation has been carried out to study dynamic performance of the hydraulic mount.
Modelling and simulating fire tube boiler performance
DEFF Research Database (Denmark)
Sørensen, K.; Condra, T.; Houbak, Niels;
2003-01-01
A model for a flue gas boiler covering the flue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been defined for the furnace, the convection zone (split in 2......: a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently Mat......Lab/Simulink has been applied for carrying out the simulations. To be able to verify the simulated results experiments has been carried out on a full scale boiler plant....
Modelling and simulating fire tube boiler performance
DEFF Research Database (Denmark)
Sørensen, Kim; Karstensen, Claus; Condra, Thomas Joseph;
2003-01-01
A model for a ue gas boiler covering the ue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been dened for the furnace, the convection zone (split in 2: a zone...... submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic- Equation system (DAE). Subsequently MatLab/Simulink has...... been applied for carrying out the simulations. To be able to verify the simulated results an experiments has been carried out on a full scale boiler plant....
Directory of Open Access Journals (Sweden)
M. Habibi
2009-01-01
Full Text Available Problem statement: A successful operation of rapid prototyping process depends on software and hardware which are used in RP machines. About software, an efficient technique is required to slice the CAD model. Several slicing methods are used for slicing from Standard Triangulation Language (STL files, such as direct slicing and adaptive slicing. Using these methods reduce accuracy of physical part or increase process time. About hardware, in Stereolithography (SLA apparatus, two mirrors have been used to reflect laser beam. Approach: In this study new algorithms were developed for part slicing from STL file and modifying the laser beam path such as: Derivation of contours in each layer, generate contour family tree, detective arcs and modifying laser beam path. A modified mechanism was designed and developed based on only one mirror to reflect laser beam. Results: These algorithms were used in a visual basic interface and the developed mechanism was implemented in a prototype apparatus. Conclusion: Developed algorithms decreased CAD model slicing time and generated more accurate laser beam path than usual methods and fabricated apparatus decreased scanning mechanism complexity and volume of the scanning system.
Computer simulations of the random barrier model
DEFF Research Database (Denmark)
Schrøder, Thomas; Dyre, Jeppe
2002-01-01
A brief review of experimental facts regarding ac electronic and ionic conduction in disordered solids is given followed by a discussion of what is perhaps the simplest realistic model, the random barrier model (symmetric hopping model). Results from large scale computer simulations are presented......, focusing on universality of the ac response in the extreme disorder limit. Finally, some important unsolved problems relating to hopping models for ac conduction are listed....
Energy Technology Data Exchange (ETDEWEB)
Ribeiro, Joao Luiz Batista [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Fundacao COPPETEC. Lab. de Instrumentacao Nuclear], e-mail: jlbr.coppetec@petrobras.com.br; Queiroz Neto, Joao Crisosthomo de; D' Almeida, Arnaldo Rodrigues; Souza, Lenita Rangel de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas da Petrobras (CENPES). Gerencia de Tecnologia e Engenharia de Pocos], e-mail: joaoqueiroz@petrobras.com.br; e-mail: arda@petrobras.com.br; e-mail: lenita@petrobras.com.br; Bianco, Luis Carlos Baralho [PETROBRAS, Rio de Janeiro, RJ (Brazil). Unidade de Negocio de Exploracao e Producao do Rio de Janeiro. Gerencia de Engenharia de Pocos], e-mail: lbianco@petrobras.com.br; Campo, Elisabete Ferreira [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas da Petrobras (CENPES). Gerencia de Tecnologia de Recuperacao e Analise de Reservatorios], e-mail: betefc@petrobras.com.br
2006-12-15
While oil and gas producer wells have the advantage of being able to naturally expel damaging particles produced during the drilling and/or completion phase, water injectors are prone to accumulating damaging substances during their operation . In order to remove those substances and restore the potential injectivity of these wells, acid jobs are usually required. One of the major challenges of these operations is to achieve successful treatment diversion. If the interval consists of layers with different permeabilities, the acid will preferably penetrate high permeable layers, leaving the zones of minor permeability without treatment. For diversion to occur, a highly effective material quantity and concentration needs to be applied. The diverting agent must also be non-damaging, low-cost and easy-to-use. The diverting agent studied performed well for permeabilities up to 3 Darcy. The main advantage of the product, besides its high divergence capacity, is the specific action of forming channels in the pores of the matrix where only oil can flow. Therefore, due to it's high hygroscopic characteristics, captures the water around the pores. Also , the product is capable of self-removal after treatment, with the oil produced in the treated well, which eliminates the need for subsequent treatments that would increase time and cost of the operation. In this study, an X-Ray Computerized Tomography (CT) scanner was used to evaluate in real-time the performance of the diverting agent in rock-fluid interactions. A special aluminum cell (physical simulator) was designed to simulate as closely as possible the conditions found in a real oil well. These conditions include, for example, pressure, temperature, fluid pressure injection, permeability, porosity and oil and water saturations of the studied reservoir. A sequence of tests that were performed in different unconsolidated sandstones, which simulated Campos Basin deep water fields, confirmed the system
Modeling and simulating of unloading welding transformer
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The simulation model of an unloading welding transformer was established on the basis of MATLAB software, and the modeling principle was described in detail in the paper. The model was made up of three sub-models, i.e. the linear inductor sub-model, the non-linear inductor sub-model and series connection sub-model controlled by current, and these sub-models were jointed together by means of segmented linearization. The simulating results showed that, in the conditions of the high convert frequency and the large cross section of the magnet core of a welding transformer, the non-linear inductor sub-model can be substituted by a linear inductor sub-model in the model; and the leakage reactance in the welding transformer is one of the main reasons of producing over-current and over-voltage in the inverter. The simulation results demonstrate that the over-voltage produced by leakage reactance is nearly two times of the input voltage supplied to the transformer, and the lasting time of over-voltage depends on time constant τ1. With reducing of τ1, the amplitude of the over-current will increase, and the lasting time becomes shorter. Contrarily, with increasing of τ1, the amplitude of the over-current will decrease, and the lasting time becomes longer. The model has played the important role for the development of the inverter resistance welding machine.
Revolutions in energy through modeling and simulation
Energy Technology Data Exchange (ETDEWEB)
Tatro, M.; Woodard, J.
1998-08-01
The development and application of energy technologies for all aspects from generation to storage have improved dramatically with the advent of advanced computational tools, particularly modeling and simulation. Modeling and simulation are not new to energy technology development, and have been used extensively ever since the first commercial computers were available. However, recent advances in computing power and access have broadened the extent and use, and, through increased fidelity (i.e., accuracy) of the models due to greatly enhanced computing power, the increased reliance on modeling and simulation has shifted the balance point between modeling and experimentation. The complex nature of energy technologies has motivated researchers to use these tools to understand better performance, reliability and cost issues related to energy. The tools originated in sciences such as the strength of materials (nuclear reactor containment vessels); physics, heat transfer and fluid flow (oil production); chemistry, physics, and electronics (photovoltaics); and geosciences and fluid flow (oil exploration and reservoir storage). Other tools include mathematics, such as statistics, for assessing project risks. This paper describes a few advancements made possible by these tools and explores the benefits and costs of their use, particularly as they relate to the acceleration of energy technology development. The computational complexity ranges from basic spreadsheets to complex numerical simulations using hardware ranging from personal computers (PCs) to Cray computers. In all cases, the benefits of using modeling and simulation relate to lower risks, accelerated technology development, or lower cost projects.
Inventory Reduction Using Business Process Reengineering and Simulation Modeling.
1996-12-01
center is analyzed using simulation modeling and business process reengineering (BPR) concepts. The two simulation models were designed and evaluated by...reengineering and simulation modeling offer powerful tools to aid the manager in reducing cycle time and inventory levels.
Computerized mouse pupil size measurement for pupillary light reflex analysis.
Lu, Wei; Tan, Jinglu; Zhang, Keqing; Lei, Bo
2008-06-01
Accurate measurement of pupil size is essential for pupillary light reflex (PLR) analysis in clinical diagnosis and vision research. Low pupil-iris contrast, corneal reflection, artifacts and noises in infrared eye imaging pose challenges for automated pupil detection and measurement. This paper describes a computerized method for pupil detection or identification. After segmentation by a region-growing algorithm, pupils are detected by an iterative randomized Hough transform (IRHT) with an elliptical model. The IRHT iteratively suppresses the effects of extraneous structures and noise, yielding reliable measurements. Experimental results with 72 images showed a mean absolute difference of 3.84% between computerized and manual measurements. The inter-run variation for the computerized method (1.24%) was much smaller than the inter-observer variation for the manual method (7.45%), suggesting a higher level of consistency of the former. The computerized method could facilitate PLR analysis and other non-invasive functional tests that require pupil size measurements.
Simulation and modeling of turbulent flows
Gatski, Thomas B; Lumley, John L
1996-01-01
This book provides students and researchers in fluid engineering with an up-to-date overview of turbulent flow research in the areas of simulation and modeling. A key element of the book is the systematic, rational development of turbulence closure models and related aspects of modern turbulent flow theory and prediction. Starting with a review of the spectral dynamics of homogenous and inhomogeneous turbulent flows, succeeding chapters deal with numerical simulation techniques, renormalization group methods and turbulent closure modeling. Each chapter is authored by recognized leaders in their respective fields, and each provides a thorough and cohesive treatment of the subject.
Modeling & Simulation Executive Agent Panel
2007-11-02
Richard W. ; 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME AND ADDRESS Office of the Oceanographer of the Navy...acquisition, and training communities.” MSEA Role • Facilitator in the project startup phase • Catalyst during development • Certifier in the...ACOUSTIC MODELS Parabolic Equation 5.0 ASTRAL 5.0 ASPM 4.3 Gaussian Ray Bundle 1.0 High Freq Env Acoustic (HFEVA) 1.0 COLOSSUS II 1.0 Low Freq Bottom LOSS
MODELLING, SIMULATING AND OPTIMIZING BOILERS
DEFF Research Database (Denmark)
Sørensen, K.; Condra, T.; Houbak, Niels
2003-01-01
, and the total stress level (i.e. stresses introduced due to internal pressure plus stresses introduced due to temperature gradients) must always be kept below the allowable stress level. In this way, the increased water-/steam space that should allow for better dynamic performance, in the end causes limited...... freedom with respect to dynamic operation of the plant. By means of an objective function including as well the price of the plant as a quantification of the value of dynamic operation of the plant an optimization is carried out. The dynamic model of the boiler plant is applied to define parts...
Modelling, simulating and optimizing Boilers
DEFF Research Database (Denmark)
Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels
2003-01-01
, and the total stress level (i.e. stresses introduced due to internal pressure plus stresses introduced due to temperature gradients) must always be kept below the allowable stress level. In this way, the increased water-/steam space that should allow for better dynamic performance, in the end causes limited...... freedom with respect to dynamic operation of the plant. By means of an objective function including as well the price of the plant as a quantication of the value of dynamic operation of the plant an optimization is carried out. The dynamic model of the boiler plant is applied to dene parts...
Simulering af dagslys i digitale modeller
DEFF Research Database (Denmark)
Villaume, René Domine; Ørstrup, Finn Rude
2004-01-01
Projektet undersøger via forskellige simuleringer af dagslys, kvaliteten af visualiseringer af komplekse lysforhold i digitale modeller i forbindelse med formidling af arkitektur via nettet. I en digital 3D model af Utzon Associates Paustians hus, simulers naturligt dagslysindfald med forskellig...... Renderingsmetoder som: "shaded render" / ”raytraceing” / "Final Gather / ”Global Illumination”...
Validity of microgravity simulation models on earth
DEFF Research Database (Denmark)
Regnard, J; Heer, M; Drummer, C
2001-01-01
Many studies have used water immersion and head-down bed rest as experimental models to simulate responses to microgravity. However, some data collected during space missions are at variance or in contrast with observations collected from experimental models. These discrepancies could reflect inc...
Molecular simulation and modeling of complex I.
Hummer, Gerhard; Wikström, Mårten
2016-07-01
Molecular modeling and molecular dynamics simulations play an important role in the functional characterization of complex I. With its large size and complicated function, linking quinone reduction to proton pumping across a membrane, complex I poses unique modeling challenges. Nonetheless, simulations have already helped in the identification of possible proton transfer pathways. Simulations have also shed light on the coupling between electron and proton transfer, thus pointing the way in the search for the mechanistic principles underlying the proton pump. In addition to reviewing what has already been achieved in complex I modeling, we aim here to identify pressing issues and to provide guidance for future research to harness the power of modeling in the functional characterization of complex I. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt. Copyright © 2016 Elsevier B.V. All rights reserved.
Hybrid simulation models of production networks
Kouikoglou, Vassilis S
2001-01-01
This book is concerned with a most important area of industrial production, that of analysis and optimization of production lines and networks using discrete-event models and simulation. The book introduces a novel approach that combines analytic models and discrete-event simulation. Unlike conventional piece-by-piece simulation, this method observes a reduced number of events between which the evolution of the system is tracked analytically. Using this hybrid approach, several models are developed for the analysis of production lines and networks. The hybrid approach combines speed and accuracy for exceptional analysis of most practical situations. A number of optimization problems, involving buffer design, workforce planning, and production control, are solved through the use of hybrid models.
Majid, Mazlina Abdul; Siebers, Peer-Olaf
2010-01-01
In this paper, we investigate output accuracy for a Discrete Event Simulation (DES) model and Agent Based Simulation (ABS) model. The purpose of this investigation is to find out which of these simulation techniques is the best one for modelling human reactive behaviour in the retail sector. In order to study the output accuracy in both models, we have carried out a validation experiment in which we compared the results from our simulation models to the performance of a real system. Our experiment was carried out using a large UK department store as a case study. We had to determine an efficient implementation of management policy in the store's fitting room using DES and ABS. Overall, we have found that both simulation models were a good representation of the real system when modelling human reactive behaviour.
Power electronics system modeling and simulation
Energy Technology Data Exchange (ETDEWEB)
Lai, Jih-Sheng
1994-12-31
This paper introduces control system design based softwares, SIMNON and MATLAB/SIMULINK, for power electronics system simulation. A complete power electronics system typically consists of a rectifier bridge along with its smoothing capacitor, an inverter, and a motor. The system components, featuring discrete or continuous, linear or nonlinear, are modeled in mathematical equations. Inverter control methods,such as pulse-width-modulation and hysteresis current control, are expressed in either computer algorithms or digital circuits. After describing component models and control methods, computer programs are then developed for complete systems simulation. Simulation results are mainly used for studying system performances, such as input and output current harmonics, torque ripples, and speed responses. Key computer programs and simulation results are demonstrated for educational purposes.
Simulation of Gravity Currents Using VOF Model
Institute of Scientific and Technical Information of China (English)
邹建锋; 黄钰期; 应新亚; 任安禄
2002-01-01
By the Volume of Fluid (VOF) multiphase flow model two-dimensional gravity currents with three phases including air are numerically simulated in this article. The necessity of consideration of turbulence effect for high Reynolds numbers is demonstrated quantitatively by LES (the Large Eddy Simulation) turbulence model. The gravity currents are simulated for h ≠ H as well as h = H, where h is the depth of the gravity current before the release and H is the depth of the intruded fluid. Uprising of swell occurs when a current flows horizontally into another lighter one for h ≠ H. The problems under what condition the uprising of swell occurs and how long it takes are considered in this article. All the simulated results are in reasonable agreement with the experimental results available.
Development of NASA's Models and Simulations Standard
Bertch, William J.; Zang, Thomas A.; Steele, Martin J.
2008-01-01
From the Space Shuttle Columbia Accident Investigation, there were several NASA-wide actions that were initiated. One of these actions was to develop a standard for development, documentation, and operation of Models and Simulations. Over the course of two-and-a-half years, a team of NASA engineers, representing nine of the ten NASA Centers developed a Models and Simulation Standard to address this action. The standard consists of two parts. The first is the traditional requirements section addressing programmatics, development, documentation, verification, validation, and the reporting of results from both the M&S analysis and the examination of compliance with this standard. The second part is a scale for evaluating the credibility of model and simulation results using levels of merit associated with 8 key factors. This paper provides an historical account of the challenges faced by and the processes used in this committee-based development effort. This account provides insights into how other agencies might approach similar developments. Furthermore, we discuss some specific applications of models and simulations used to assess the impact of this standard on future model and simulation activities.
Modelling and Simulation of Crude Oil Dispersion
Directory of Open Access Journals (Sweden)
Abdulfatai JIMOH
2006-01-01
Full Text Available This research work was carried out to develop a model equation for the dispersion of crude oil in water. Seven different crude oils (Bonny Light, Antan Terminal, Bonny Medium, Qua Iboe Light, Brass Light Mbede, Forcados Blend and Heavy H were used as the subject crude oils. The developed model equation in this project which is given as...It was developed starting from the equation for the oil dispersion rate in water which is given as...The developed equation was then simulated with the aid of MathCAD 2000 Professional software. The experimental and model results obtained from the simulation of the model equation were plotted on the same axis against time of dispersion. The model results revealed close fittings between the experimental and the model results because the correlation coefficients and the r-square values calculated using Spreadsheet Program were both found to be unity (1.00.
Simulation Modeling of Software Development Processes
Calavaro, G. F.; Basili, V. R.; Iazeolla, G.
1996-01-01
A simulation modeling approach is proposed for the prediction of software process productivity indices, such as cost and time-to-market, and the sensitivity analysis of such indices to changes in the organization parameters and user requirements. The approach uses a timed Petri Net and Object Oriented top-down model specification. Results demonstrate the model representativeness, and its usefulness in verifying process conformance to expectations, and in performing continuous process improvement and optimization.
Incorporation of RAM techniques into simulation modeling
Energy Technology Data Exchange (ETDEWEB)
Nelson, S.C. Jr.; Haire, M.J.; Schryver, J.C.
1995-07-01
This work concludes that reliability, availability, and maintainability (RAM) analytical techniques can be incorporated into computer network simulation modeling to yield an important new analytical tool. This paper describes the incorporation of failure and repair information into network simulation to build a stochastic computer model represents the RAM Performance of two vehicles being developed for the US Army: The Advanced Field Artillery System (AFAS) and the Future Armored Resupply Vehicle (FARV). The AFAS is the US Army`s next generation self-propelled cannon artillery system. The FARV is a resupply vehicle for the AFAS. Both vehicles utilize automation technologies to improve the operational performance of the vehicles and reduce manpower. The network simulation model used in this work is task based. The model programmed in this application requirements a typical battle mission and the failures and repairs that occur during that battle. Each task that the FARV performs--upload, travel to the AFAS, refuel, perform tactical/survivability moves, return to logistic resupply, etc.--is modeled. Such a model reproduces a model reproduces operational phenomena (e.g., failures and repairs) that are likely to occur in actual performance. Simulation tasks are modeled as discrete chronological steps; after the completion of each task decisions are programmed that determine the next path to be followed. The result is a complex logic diagram or network. The network simulation model is developed within a hierarchy of vehicle systems, subsystems, and equipment and includes failure management subnetworks. RAM information and other performance measures are collected which have impact on design requirements. Design changes are evaluated through ``what if`` questions, sensitivity studies, and battle scenario changes.
Testing turbulent closure models with convection simulations
Snellman, J E; Mantere, M J; Rheinhardt, M; Dintrans, B
2012-01-01
Aims: To compare simple analytical closure models of turbulent Boussinesq convection for stellar applications with direct three-dimensional simulations both in homogeneous and inhomogeneous (bounded) setups. Methods: We use simple analytical closure models to compute the fluxes of angular momentum and heat as a function of rotation rate measured by the Taylor number. We also investigate cases with varying angles between the angular velocity and gravity vectors, corresponding to locating the computational domain at different latitudes ranging from the pole to the equator of the star. We perform three-dimensional numerical simulations in the same parameter regimes for comparison. The free parameters appearing in the closure models are calibrated by two fit methods using simulation data. Unique determination of the closure parameters is possible only in the non-rotating case and when the system is placed at the pole. In the other cases the fit procedures yield somewhat differing results. The quality of the closu...
Analyzing Strategic Business Rules through Simulation Modeling
Orta, Elena; Ruiz, Mercedes; Toro, Miguel
Service Oriented Architecture (SOA) holds promise for business agility since it allows business process to change to meet new customer demands or market needs without causing a cascade effect of changes in the underlying IT systems. Business rules are the instrument chosen to help business and IT to collaborate. In this paper, we propose the utilization of simulation models to model and simulate strategic business rules that are then disaggregated at different levels of an SOA architecture. Our proposal is aimed to help find a good configuration for strategic business objectives and IT parameters. The paper includes a case study where a simulation model is built to help business decision-making in a context where finding a good configuration for different business parameters and performance is too complex to analyze by trial and error.
IGT-Open: An open-source, computerized version of the Iowa Gambling Task.
Dancy, Christopher L; Ritter, Frank E
2017-06-01
The Iowa Gambling Task (IGT) is commonly used to understand the processes involved in decision-making. Though the task was originally run without a computer, using a computerized version of the task has become typical. These computerized versions of the IGT are useful, because they can make the task more standardized across studies and allow for the task to be used in environments where a physical version of the task may be difficult or impossible to use (e.g., while collecting brain imaging data). Though these computerized versions of the IGT have been useful for experimentation, having multiple software implementations of the task could present reliability issues. We present an open-source software version of the Iowa Gambling Task (called IGT-Open) that allows for millisecond visual presentation accuracy and is freely available to be used and modified. This software has been used to collect data from human subjects and also has been used to run model-based simulations with computational process models developed to run in the ACT-R architecture.
Modeling and simulation with operator scaling
Cohen, Serge; Rosinski, Jan
2009-01-01
Self-similar processes are useful in modeling diverse phenomena that exhibit scaling properties. Operator scaling allows a different scale factor in each coordinate. This paper develops practical methods for modeling and simulating stochastic processes with operator scaling. A simulation method for operator stable Levy processes is developed, based on a series representation, along with a Gaussian approximation of the small jumps. Several examples are given to illustrate practical applications. A classification of operator stable Levy processes in two dimensions is provided according to their exponents and symmetry groups. We conclude with some remarks and extensions to general operator self-similar processes.
Hemispherical sky simulator for daylighting model studies
Energy Technology Data Exchange (ETDEWEB)
Selkowitz, S.
1981-07-01
The design of a 24-foot-diameter hemispherical sky simulator recently completed at LBL is described. The goal was to produce a facility in which large models could be tested; which was suitable for research, teaching, and design; which could provide a uniform sky, an overcast sky, and several clear-sky luminance distributions, as well as accommodating an artificial sun. Initial operating experience with the facility is described, the sky simulator capabilities are reviewed, and its strengths and weaknesses relative to outdoor modeling tests are discussed.
Wind Shear Target Echo Modeling and Simulation
Directory of Open Access Journals (Sweden)
Xiaoyang Liu
2015-01-01
Full Text Available Wind shear is a dangerous atmospheric phenomenon in aviation. Wind shear is defined as a sudden change of speed or direction of the wind. In order to analyze the influence of wind shear on the efficiency of the airplane, this paper proposes a mathematical model of point target rain echo and weather target signal echo based on Doppler effect. The wind field model is developed in this paper, and the antenna model is also studied by using Bessel function. The spectrum distribution of symmetric and asymmetric wind fields is researched by using the mathematical model proposed in this paper. The simulation results are in accordance with radial velocity component, and the simulation results also confirm the correctness of the established model of antenna.
Nuclear reactor core modelling in multifunctional simulators
Energy Technology Data Exchange (ETDEWEB)
Puska, E.K. [VTT Energy, Nuclear Energy, Espoo (Finland)
1999-06-01
The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been
Battery thermal models for hybrid vehicle simulations
Pesaran, Ahmad A.
This paper summarizes battery thermal modeling capabilities for: (1) an advanced vehicle simulator (ADVISOR); and (2) battery module and pack thermal design. The National Renewable Energy Laboratory's (NREL's) ADVISOR is developed in the Matlab/Simulink environment. There are several battery models in ADVISOR for various chemistry types. Each one of these models requires a thermal model to predict the temperature change that could affect battery performance parameters, such as resistance, capacity and state of charges. A lumped capacitance battery thermal model in the Matlab/Simulink environment was developed that included the ADVISOR battery performance models. For thermal evaluation and design of battery modules and packs, NREL has been using various computer aided engineering tools including commercial finite element analysis software. This paper will discuss the thermal ADVISOR battery model and its results, along with the results of finite element modeling that were presented at the workshop on "Development of Advanced Battery Engineering Models" in August 2001.
Kanban simulation model for production process optimization
Directory of Open Access Journals (Sweden)
Golchev Riste
2015-01-01
Full Text Available A long time has passed since the KANBAN system has been established as an efficient method for coping with the excessive inventory. Still, the possibilities for its improvement through its integration with other different approaches should be investigated further. The basic research challenge of this paper is to present benefits of KANBAN implementation supported with Discrete Event Simulation (DES. In that direction, at the beginning, the basics of KANBAN system are presented with emphasis on the information and material flow, together with a methodology for implementation of KANBAN system. Certain analysis on combining the simulation with this methodology is presented. The paper is concluded with a practical example which shows that through understanding the philosophy of the implementation methodology of KANBAN system and the simulation methodology, a simulation model can be created which can serve as a basis for a variety of experiments that can be conducted within a short period of time, resulting with production process optimization.
Energy Technology Data Exchange (ETDEWEB)
Franze, Daniel L.; Bertolo, Antonio C.N.; Gama, Andressa F.; Moraes, Eder R. [Universidade de Sao Paulo (GIMN/USP), Ribeirao Preto, SP (Brazil). Grupo de Imagens em Medicina Nuclear
2016-07-01
Whereas sensitivity and spatial resolution of PET images formed in coincidence systems may exhibit improvements with reduction of the distance between the detectors. Furthermore, since the human cross section not be a circle three different detection geometries of a PET system have been simulated; a circular and two ellipticals. The performance comparison was performed by the sensitivity, resolution and the Noise Equivalent Count Rate curve. The results show that elliptical systems may experience 25% lower cost detectors, increased sensitivity to 63%. The resolution improvements introduced in X direction, large loss in the Y direction, although the use of iterative reconstruction can reduce the loss in resolution. The reduction of peak NEC curve indicates the image with better quality is achieved with lower activity of the source. (author)
TRANSFORM - TRANsient Simulation Framework of Reconfigurable Models
Energy Technology Data Exchange (ETDEWEB)
2017-09-01
Existing development tools for early stage design and scoping of energy systems are often time consuming to use, proprietary, and do not contain the necessary function to model complete systems (i.e., controls, primary, and secondary systems) in a common platform. The Modelica programming language based TRANSFORM tool (1) provides a standardized, common simulation environment for early design of energy systems (i.e., power plants), (2) provides a library of baseline component modules to be assembled into full plant models using available geometry, design, and thermal-hydraulic data, (3) defines modeling conventions for interconnecting component models, and (4) establishes user interfaces and support tools to facilitate simulation development (i.e., configuration and parameterization), execution, and results display and capture.
EXACT SIMULATION OF A BOOLEAN MODEL
Directory of Open Access Journals (Sweden)
Christian Lantuéjoul
2013-06-01
Full Text Available A Boolean model is a union of independent objects (compact random subsets located at Poisson points. Two algorithms are proposed for simulating a Boolean model in a bounded domain. The first one applies only to stationary models. It generates the objects prior to their Poisson locations. Two examples illustrate its applicability. The second algorithm applies to stationary and non-stationary models. It generates the Poisson points prior to the objects. Its practical difficulties of implementation are discussed. Both algorithms are based on importance sampling techniques, and the generated objects are weighted.
Biological transportation networks: Modeling and simulation
Albi, Giacomo
2015-09-15
We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation and angiogenesis) and ion transportation networks (e.g., neural networks) is explained in detail and basic analytical features like the gradient flow structure of the fluid transportation network model and the impact of the model parameters on the geometry and topology of network formation are analyzed. We also present a numerical finite-element based discretization scheme and discuss sample cases of network formation simulations.
Modeling and Simulation of Nuclear Fuel Materials
Energy Technology Data Exchange (ETDEWEB)
Devanathan, Ramaswami; Van Brutzel, Laurent; Chartier, Alan; Gueneau, Christine; Mattsson, Ann E.; Tikare, Veena; Bartel, Timothy; Besmann, T. M.; Stan, Marius; Van Uffelen, Paul
2010-10-01
We review the state of modeling and simulation of nuclear fuels with emphasis on the most widely used nuclear fuel, UO2. The hierarchical scheme presented represents a science-based approach to modeling nuclear fuels by progressively passing information in several stages from ab initio to continuum levels. Such an approach is essential to overcome the challenges posed by radioactive materials handling, experimental limitations in modeling extreme conditions and accident scenarios, and the small time and distance scales of fundamental defect processes. When used in conjunction with experimental validation, this multiscale modeling scheme can provide valuable guidance to development of fuel for advanced reactors to meet rising global energy demand.
Simulation modeling of health care policy.
Glied, Sherry; Tilipman, Nicholas
2010-01-01
Simulation modeling of health reform is a standard part of policy development and, in the United States, a required element in enacting health reform legislation. Modelers use three types of basic structures to build models of the health system: microsimulation, individual choice, and cell-based. These frameworks are filled in with data on baseline characteristics of the system and parameters describing individual behavior. Available data on baseline characteristics are imprecise, and estimates of key empirical parameters vary widely. A comparison of estimated and realized consequences of several health reform proposals suggests that models provided reasonably accurate estimates, with confidence bounds of approximately 30%.
Modeling and simulation of epidemic spread
DEFF Research Database (Denmark)
Shatnawi, Maad; Lazarova-Molnar, Sanja; Zaki, Nazar
2013-01-01
and control such epidemics. This paper presents an overview of the epidemic spread modeling and simulation, and summarizes the main technical challenges in this field. It further investigates the most relevant recent approaches carried out towards this perspective and provides a comparison and classification...
Object Oriented Modelling and Dynamical Simulation
DEFF Research Database (Denmark)
Wagner, Falko Jens; Poulsen, Mikael Zebbelin
1998-01-01
This report with appendix describes the work done in master project at DTU.The goal of the project was to develop a concept for simulation of dynamical systems based on object oriented methods.The result was a library of C++-classes, for use when both building componentbased models and when...
Modeling and Simulating Virtual Anatomical Humans
Madehkhaksar, Forough; Luo, Zhiping; Pronost, Nicolas; Egges, Arjan
2014-01-01
This chapter presents human musculoskeletal modeling and simulation as a challenging field that lies between biomechanics and computer animation. One of the main goals of computer animation research is to develop algorithms and systems that produce plausible motion. On the other hand, the main chall
Modeling and Simulation in Healthcare Future Directions
2010-07-13
Quantify performance (Competency - based) 6. Simulate before practice ( Digital Libraries ) Classic Education and Examination What is the REVOLUTION in...av $800,000 yr 2.) Actor patients - $250,000 – $400,000/yr 2. Digital Libraries or synthetic tissue models a. Subscription vs up-front costs
Simulation Versus Models: Which One and When?
Dorn, William S.
1975-01-01
Describes two types of computer-based experiments: simulation (which assumes no student knowledge of the workings of the computer program) is recommended for experiments aimed at inductive reasoning; and modeling (which assumes student understanding of the computer program) is recommended for deductive processes. (MLH)
Love Kills:. Simulations in Penna Ageing Model
Stauffer, Dietrich; Cebrat, Stanisław; Penna, T. J. P.; Sousa, A. O.
The standard Penna ageing model with sexual reproduction is enlarged by adding additional bit-strings for love: Marriage happens only if the male love strings are sufficiently different from the female ones. We simulate at what level of required difference the population dies out.
Inverse modeling for Large-Eddy simulation
Geurts, Bernardus J.
1998-01-01
Approximate higher order polynomial inversion of the top-hat filter is developed with which the turbulent stress tensor in Large-Eddy Simulation can be consistently represented using the filtered field. Generalized (mixed) similarity models are proposed which improved the agreement with the kinetic
Microdata Simulation Modeling After Twenty Years.
Haveman, Robert H.
1986-01-01
This article describes the method and the development of microdata simulation modeling over the past two decades. After tracing a brief history of this evaluation method, its problems and prospects are assessed. The effects of this research method on the development of the social sciences are examined. (JAZ)
Simulation Modeling on the Macintosh using STELLA.
Costanza, Robert
1987-01-01
Describes a new software package for the Apple Macintosh computer which can be used to create elaborate simulation models in a fraction of the time usually required without using a programming language. Illustrates the use of the software which relates to water usage. (TW)
Simulation Modeling of Radio Direction Finding Results
Directory of Open Access Journals (Sweden)
K. Pelikan
1994-12-01
Full Text Available It is sometimes difficult to determine analytically error probabilities of direction finding results for evaluating algorithms of practical interest. Probalistic simulation models are described in this paper that can be to study error performance of new direction finding systems or to geographical modifications of existing configurations.
A Prison/Parole System Simulation Model,
parole system on future prison and parole populations. A simulation model is presented, viewing a prison / parole system as a feedback process for...ciminal offenders . Transitions among the states in which an offender might be located, imprisoned, paroled , and discharged, are assumed to be in...accordance with a discrete time semi-Markov process. Projected prison and parole populations for sample data and applications of the model are discussed. (Author)
Twitter's tweet method modelling and simulation
Sarlis, Apostolos S.; Sakas, Damianos P.; Vlachos, D. S.
2015-02-01
This paper seeks to purpose the concept of Twitter marketing methods. The tools that Twitter provides are modelled and simulated using iThink in the context of a Twitter media-marketing agency. The paper has leveraged the system's dynamic paradigm to conduct Facebook marketing tools and methods modelling, using iThink™ system to implement them. It uses the design science research methodology for the proof of concept of the models and modelling processes. The following models have been developed for a twitter marketing agent/company and tested in real circumstances and with real numbers. These models were finalized through a number of revisions and iterators of the design, develop, simulate, test and evaluate. It also addresses these methods that suit most organized promotion through targeting, to the Twitter social media service. The validity and usefulness of these Twitter marketing methods models for the day-to-day decision making are authenticated by the management of the company organization. It implements system dynamics concepts of Twitter marketing methods modelling and produce models of various Twitter marketing situations. The Tweet method that Twitter provides can be adjusted, depending on the situation, in order to maximize the profit of the company/agent.
Fault diagnosis based on continuous simulation models
Feyock, Stefan
1987-01-01
The results are described of an investigation of techniques for using continuous simulation models as basis for reasoning about physical systems, with emphasis on the diagnosis of system faults. It is assumed that a continuous simulation model of the properly operating system is available. Malfunctions are diagnosed by posing the question: how can we make the model behave like that. The adjustments that must be made to the model to produce the observed behavior usually provide definitive clues to the nature of the malfunction. A novel application of Dijkstra's weakest precondition predicate transformer is used to derive the preconditions for producing the required model behavior. To minimize the size of the search space, an envisionment generator based on interval mathematics was developed. In addition to its intended application, the ability to generate qualitative state spaces automatically from quantitative simulations proved to be a fruitful avenue of investigation in its own right. Implementations of the Dijkstra transform and the envisionment generator are reproduced in the Appendix.
Modelling and simulation of affinity membrane adsorption.
Boi, Cristiana; Dimartino, Simone; Sarti, Giulio C
2007-08-24
A mathematical model for the adsorption of biomolecules on affinity membranes is presented. The model considers convection, diffusion and adsorption kinetics on the membrane module as well as the influence of dead end volumes and lag times; an analysis of flow distribution on the whole system is also included. The parameters used in the simulations were obtained from equilibrium and dynamic experimental data measured for the adsorption of human IgG on A2P-Sartoepoxy affinity membranes. The identification of a bi-Langmuir kinetic mechanisms for the experimental system investigated was paramount for a correct process description and the simulated breakthrough curves were in good agreement with the experimental data. The proposed model provides a new insight into the phenomena involved in the adsorption on affinity membranes and it is a valuable tool to assess the use of membrane adsorbers in large scale processes.
Multiphase reacting flows modelling and simulation
Marchisio, Daniele L
2007-01-01
The papers in this book describe the most widely applicable modeling approaches and are organized in six groups covering from fundamentals to relevant applications. In the first part, some fundamentals of multiphase turbulent reacting flows are covered. In particular the introduction focuses on basic notions of turbulence theory in single-phase and multi-phase systems as well as on the interaction between turbulence and chemistry. In the second part, models for the physical and chemical processes involved are discussed. Among other things, particular emphasis is given to turbulence modeling strategies for multiphase flows based on the kinetic theory for granular flows. Next, the different numerical methods based on Lagrangian and/or Eulerian schemes are presented. In particular the most popular numerical approaches of computational fluid dynamics codes are described (i.e., Direct Numerical Simulation, Large Eddy Simulation, and Reynolds-Averaged Navier-Stokes approach). The book will cover particle-based meth...
Modeling, simulation and optimization of bipedal walking
Berns, Karsten
2013-01-01
The model-based investigation of motions of anthropomorphic systems is an important interdisciplinary research topic involving specialists from many fields such as Robotics, Biomechanics, Physiology, Orthopedics, Psychology, Neurosciences, Sports, Computer Graphics and Applied Mathematics. This book presents a study of basic locomotion forms such as walking and running is of particular interest due to the high demand on dynamic coordination, actuator efficiency and balance control. Mathematical models and numerical simulation and optimization techniques are explained, in combination with experimental data, which can help to better understand the basic underlying mechanisms of these motions and to improve them. Example topics treated in this book are Modeling techniques for anthropomorphic bipedal walking systems Optimized walking motions for different objective functions Identification of objective functions from measurements Simulation and optimization approaches for humanoid robots Biologically inspired con...
A Superbubble Feedback Model for Galaxy Simulations
Keller, B W; Benincasa, S M; Couchman, H M P
2014-01-01
We present a new stellar feedback model that reproduces superbubbles. Superbubbles from clustered young stars evolve quite differently to individual supernovae and are substantially more efficient at generating gas motions. The essential new components of the model are thermal conduction, sub-grid evaporation and a sub-grid multi-phase treatment for cases where the simulation mass resolution is insufficient to model the early stages of the superbubble. The multi-phase stage is short compared to superbubble lifetimes. Thermal conduction physically regulates the hot gas mass without requiring a free parameter. Accurately following the hot component naturally avoids overcooling. Prior approaches tend to heat too much mass, leaving the hot ISM below $10^6$ K and susceptible to rapid cooling unless ad-hoc fixes were used. The hot phase also allows feedback energy to correctly accumulate from multiple, clustered sources, including stellar winds and supernovae. We employ high-resolution simulations of a single star ...
Advancing Material Models for Automotive Forming Simulations
Vegter, H.; An, Y.; ten Horn, C. H. L. J.; Atzema, E. H.; Roelofsen, M. E.
2005-08-01
Simulations in automotive industry need more advanced material models to achieve highly reliable forming and springback predictions. Conventional material models implemented in the FEM-simulation models are not capable to describe the plastic material behaviour during monotonic strain paths with sufficient accuracy. Recently, ESI and Corus co-operate on the implementation of an advanced material model in the FEM-code PAMSTAMP 2G. This applies to the strain hardening model, the influence of strain rate, and the description of the yield locus in these models. A subsequent challenge is the description of the material after a change of strain path. The use of advanced high strength steels in the automotive industry requires a description of plastic material behaviour of multiphase steels. The simplest variant is dual phase steel consisting of a ferritic and a martensitic phase. Multiphase materials also contain a bainitic phase in addition to the ferritic and martensitic phase. More physical descriptions of strain hardening than simple fitted Ludwik/Nadai curves are necessary. Methods to predict plastic behaviour of single-phase materials use a simple dislocation interaction model based on the formed cells structures only. At Corus, a new method is proposed to predict plastic behaviour of multiphase materials have to take hard phases into account, which deform less easily. The resulting deformation gradients create geometrically necessary dislocations. Additional micro-structural information such as morphology and size of hard phase particles or grains is necessary to derive the strain hardening models for this type of materials. Measurements available from the Numisheet benchmarks allow these models to be validated. At Corus, additional measured values are available from cross-die tests. This laboratory test can attain critical deformations by large variations in blank size and processing conditions. The tests are a powerful tool in optimising forming simulations
Computerized proof techniques for undergraduates
Smith, Christopher J.; Tefera, Akalu; Zeleke, Aklilu
2012-12-01
The use of computer algebra systems such as Maple and Mathematica is becoming increasingly important and widespread in mathematics learning, teaching and research. In this article, we present computerized proof techniques of Gosper, Wilf-Zeilberger and Zeilberger that can be used for enhancing the teaching and learning of topics in discrete mathematics. We demonstrate by examples how one can use these computerized proof techniques to raise students' interests in the discovery and proof of mathematical identities and enhance their problem-solving skills.
Modelling and simulation of thermal power plants
Energy Technology Data Exchange (ETDEWEB)
Eborn, J.
1998-02-01
Mathematical modelling and simulation are important tools when dealing with engineering systems that today are becoming increasingly more complex. Integrated production and recycling of materials are trends that give rise to heterogenous systems, which are difficult to handle within one area of expertise. Model libraries are an excellent way to package engineering knowledge of systems and units to be reused by those who are not experts in modelling. Many commercial packages provide good model libraries, but they are usually domain-specific and closed. Heterogenous, multi-domain systems requires open model libraries written in general purpose modelling languages. This thesis describes a model database for thermal power plants written in the object-oriented modelling language OMOLA. The models are based on first principles. Subunits describe volumes with pressure and enthalpy dynamics and flows of heat or different media. The subunits are used to build basic units such as pumps, valves and heat exchangers which can be used to build system models. Several applications are described; a heat recovery steam generator, equipment for juice blending, steam generation in a sulphuric acid plant and a condensing steam plate heat exchanger. Model libraries for industrial use must be validated against measured data. The thesis describes how parameter estimation methods can be used for model validation. Results from a case-study on parameter optimization of a non-linear drum boiler model show how the technique can be used 32 refs, 21 figs
Dynamics modeling and simulation of flexible airships
Li, Yuwen
The resurgence of airships has created a need for dynamics models and simulation capabilities of these lighter-than-air vehicles. The focus of this thesis is a theoretical framework that integrates the flight dynamics, structural dynamics, aerostatics and aerodynamics of flexible airships. The study begins with a dynamics model based on a rigid-body assumption. A comprehensive computation of aerodynamic effects is presented, where the aerodynamic forces and moments are categorized into various terms based on different physical effects. A series of prediction approaches for different aerodynamic effects are unified and applied to airships. The numerical results of aerodynamic derivatives and the simulated responses to control surface deflection inputs are verified by comparing to existing wind-tunnel and flight test data. With the validated aerodynamics and rigid-body modeling, the equations of motion of an elastic airship are derived by the Lagrangian formulation. The airship is modeled as a free-free Euler-Bernoulli beam and the bending deformations are represented by shape functions chosen as the free-free normal modes. In order to capture the coupling between the aerodynamic forces and the structural elasticity, local velocity on the deformed vehicle is used in the computation of aerodynamic forces. Finally, with the inertial, gravity, aerostatic and control forces incorporated, the dynamics model of a flexible airship is represented by a single set of nonlinear ordinary differential equations. The proposed model is implemented as a dynamics simulation program to analyze the dynamics characteristics of the Skyship-500 airship. Simulation results are presented to demonstrate the influence of structural deformation on the aerodynamic forces and the dynamics behavior of the airship. The nonlinear equations of motion are linearized numerically for the purpose of frequency domain analysis and for aeroelastic stability analysis. The results from the latter for the
High resolution, MRI-based, segmented, computerized head phantom
Energy Technology Data Exchange (ETDEWEB)
Zubal, I.G.; Harrell, C.R.; Smith, E.O.; Smith, A.L.; Krischlunas, P. [Yale Univ., New Haven, CT (United States). Dept. of Diagnostic Radiology
1999-01-01
The authors have created a high-resolution software phantom of the human brain which is applicable to voxel-based radiation transport calculations yielding nuclear medicine simulated images and/or internal dose estimates. A software head phantom was created from 124 transverse MRI images of a healthy normal individual. The transverse T2 slices, recorded in a 256x256 matrix from a GE Signa 2 scanner, have isotropic voxel dimensions of 1.5 mm and were manually segmented by the clinical staff. Each voxel of the phantom contains one of 62 index numbers designating anatomical, neurological, and taxonomical structures. The result is stored as a 256x256x128 byte array. Internal volumes compare favorably to those described in the ICRP Reference Man. The computerized array represents a high resolution model of a typical human brain and serves as a voxel-based anthropomorphic head phantom suitable for computer-based modeling and simulation calculations. It offers an improved realism over previous mathematically described software brain phantoms, and creates a reference standard for comparing results of newly emerging voxel-based computations. Such voxel-based computations lead the way to developing diagnostic and dosimetry calculations which can utilize patient-specific diagnostic images. However, such individualized approaches lack fast, automatic segmentation schemes for routine use; therefore, the high resolution, typical head geometry gives the most realistic patient model currently available.
Mathematical models and numerical simulation in electromagnetism
Bermúdez, Alfredo; Salgado, Pilar
2014-01-01
The book represents a basic support for a master course in electromagnetism oriented to numerical simulation. The main goal of the book is that the reader knows the boundary-value problems of partial differential equations that should be solved in order to perform computer simulation of electromagnetic processes. Moreover it includes a part devoted to electric circuit theory based on ordinary differential equations. The book is mainly oriented to electric engineering applications, going from the general to the specific, namely, from the full Maxwell’s equations to the particular cases of electrostatics, direct current, magnetostatics and eddy currents models. Apart from standard exercises related to analytical calculus, the book includes some others oriented to real-life applications solved with MaxFEM free simulation software.
Modeling and simulation of economic processes
Directory of Open Access Journals (Sweden)
Bogdan Brumar
2010-12-01
Full Text Available In general, any activity requires a longer action often characterized by a degree of uncertainty, insecurity, in terms of size of the objective pursued. Because of the complexity of real economic systems, the stochastic dependencies between different variables and parameters considered, not all systems can be adequately represented by a model that can be solved by analytical methods and covering all issues for management decision analysis-economic horizon real. Often in such cases, it is considered that the simulation technique is the only alternative available. Using simulation techniques to study real-world systems often requires a laborious work. Making a simulation experiment is a process that takes place in several stages.
Computerized sociometric assessment for preschool children
Endedijk, H.M.; Cillessen, A.H.N.
2015-01-01
In preschool classes, sociometric peer ratings are used to measure children's peer relationships. The current study examined a computerized version of preschool sociometric ratings. The psychometric properties were compared of computerized sociometric ratings and traditional peer ratings for prescho
Deep Drawing Simulations With Different Polycrystalline Models
Duchêne, Laurent; de Montleau, Pierre; Bouvier, Salima; Habraken, Anne Marie
2004-06-01
The goal of this research is to study the anisotropic material behavior during forming processes, represented by both complex yield loci and kinematic-isotropic hardening models. A first part of this paper describes the main concepts of the `Stress-strain interpolation' model that has been implemented in the non-linear finite element code Lagamine. This model consists of a local description of the yield locus based on the texture of the material through the full constraints Taylor's model. The texture evolution due to plastic deformations is computed throughout the FEM simulations. This `local yield locus' approach was initially linked to the classical isotropic Swift hardening law. Recently, a more complex hardening model was implemented: the physically-based microstructural model of Teodosiu. It takes into account intergranular heterogeneity due to the evolution of dislocation structures, that affects isotropic and kinematic hardening. The influence of the hardening model is compared to the influence of the texture evolution thanks to deep drawing simulations.
Facebook's personal page modelling and simulation
Sarlis, Apostolos S.; Sakas, Damianos P.; Vlachos, D. S.
2015-02-01
In this paper we will try to define the utility of Facebook's Personal Page marketing method. This tool that Facebook provides, is modelled and simulated using iThink in the context of a Facebook marketing agency. The paper has leveraged the system's dynamic paradigm to conduct Facebook marketing tools and methods modelling, using iThink™ system to implement them. It uses the design science research methodology for the proof of concept of the models and modelling processes. The following model has been developed for a social media marketing agent/company, Facebook platform oriented and tested in real circumstances. This model is finalized through a number of revisions and iterators of the design, development, simulation, testing and evaluation processes. The validity and usefulness of this Facebook marketing model for the day-to-day decision making are authenticated by the management of the company organization. Facebook's Personal Page method can be adjusted, depending on the situation, in order to maximize the total profit of the company which is to bring new customers, keep the interest of the old customers and deliver traffic to its website.
Towards Better Coupling of Hydrological Simulation Models
Penton, D.; Stenson, M.; Leighton, B.; Bridgart, R.
2012-12-01
Standards for model interoperability and scientific workflow software provide techniques and tools for coupling hydrological simulation models. However, model builders are yet to realize the benefits of these and continue to write ad hoc implementations and scripts. Three case studies demonstrate different approaches to coupling models, the first using tight interfaces (OpenMI), the second using a scientific workflow system (Trident) and the third using a tailored execution engine (Delft Flood Early Warning System - Delft-FEWS). No approach was objectively better than any other approach. The foremost standard for coupling hydrological models is the Open Modeling Interface (OpenMI), which defines interfaces for models to interact. An implementation of the OpenMI standard involves defining interchange terms and writing a .NET/Java wrapper around the model. An execution wrapper such as OatC.GUI or Pipistrelle executes the models. The team built two OpenMI implementations for eWater Source river system models. Once built, it was easy to swap river system models. The team encountered technical challenges with versions of the .Net framework (3.5 calling 4.0) and with the performance of the execution wrappers when running daily simulations. By design, the OpenMI interfaces are general, leaving significant decisions around the semantics of the interfaces to the implementer. Increasingly, scientific workflow tools such as Kepler, Taverna and Trident are able to replace custom scripts. These tools aim to improve the provenance and reproducibility of processing tasks. In particular, Taverna and the myExperiment website have had success making many bioinformatics workflows reusable and sharable. The team constructed Trident activities for hydrological software including IQQM, REALM and eWater Source. They built an activity generator for model builders to build activities for particular river systems. The models were linked at a simulation level, without any daily time
Modeling and simulation of the human eye
Duran, R.; Ventura, L.; Nonato, L.; Bruno, O.
2007-02-01
The computational modeling of the human eye has been wide studied for different sectors of the scientific and technological community. One of the main reasons for this increasing interest is the possibility to reproduce eye optic properties by means of computational simulations, becoming possible the development of efficient devices to treat and to correct the problems of the vision. This work explores this aspect still little investigated of the modeling of the visual system, considering a computational sketch that make possible the use of real data in the modeling and simulation of the human visual system. This new approach makes possible the individual inquiry of the optic system, assisting in the construction of new techniques used to infer vital data in medical investigations. Using corneal topography to collect real data from patients, a computational model of cornea is constructed and a set of simulations were build to ensure the correctness of the system and to investigate the effect of corneal abnormalities in retinal image formation, such as Plcido Discs, Point Spread Function, Wave front and the projection of a real image and it's visualization on retina.
A superbubble feedback model for galaxy simulations
Keller, B. W.; Wadsley, J.; Benincasa, S. M.; Couchman, H. M. P.
2014-08-01
We present a new stellar feedback model that reproduces superbubbles. Superbubbles from clustered young stars evolve quite differently to individual supernovae and are substantially more efficient at generating gas motions. The essential new components of the model are thermal conduction, subgrid evaporation and a subgrid multiphase treatment for cases where the simulation mass resolution is insufficient to model the early stages of the superbubble. The multiphase stage is short compared to superbubble lifetimes. Thermal conduction physically regulates the hot gas mass without requiring a free parameter. Accurately following the hot component naturally avoids overcooling. Prior approaches tend to heat too much mass, leaving the hot interstellar medium (ISM) below 106 K and susceptible to rapid cooling unless ad hoc fixes were used. The hot phase also allows feedback energy to correctly accumulate from multiple, clustered sources, including stellar winds and supernovae. We employ high-resolution simulations of a single star cluster to show the model is insensitive to numerical resolution, unresolved ISM structure and suppression of conduction by magnetic fields. We also simulate a Milky Way analogue and a dwarf galaxy. Both galaxies show regulated star formation and produce strong outflows.
Theory, modeling and simulation: Annual report 1993
Energy Technology Data Exchange (ETDEWEB)
Dunning, T.H. Jr.; Garrett, B.C.
1994-07-01
Developing the knowledge base needed to address the environmental restoration issues of the US Department of Energy requires a fundamental understanding of molecules and their interactions in insolation and in liquids, on surfaces, and at interfaces. To meet these needs, the PNL has established the Environmental and Molecular Sciences Laboratory (EMSL) and will soon begin construction of a new, collaborative research facility devoted to advancing the understanding of environmental molecular science. Research in the Theory, Modeling, and Simulation program (TMS), which is one of seven research directorates in the EMSL, will play a critical role in understanding molecular processes important in restoring DOE`s research, development and production sites, including understanding the migration and reactions of contaminants in soils and groundwater, the development of separation process for isolation of pollutants, the development of improved materials for waste storage, understanding the enzymatic reactions involved in the biodegradation of contaminants, and understanding the interaction of hazardous chemicals with living organisms. The research objectives of the TMS program are to apply available techniques to study fundamental molecular processes involved in natural and contaminated systems; to extend current techniques to treat molecular systems of future importance and to develop techniques for addressing problems that are computationally intractable at present; to apply molecular modeling techniques to simulate molecular processes occurring in the multispecies, multiphase systems characteristic of natural and polluted environments; and to extend current molecular modeling techniques to treat complex molecular systems and to improve the reliability and accuracy of such simulations. The program contains three research activities: Molecular Theory/Modeling, Solid State Theory, and Biomolecular Modeling/Simulation. Extended abstracts are presented for 89 studies.
Simulation modelling of fynbos ecosystems: Systems analysis and conceptual models
CSIR Research Space (South Africa)
Kruger, FJ
1985-03-01
Full Text Available This report outlines progress with the development of computer based dynamic simulation models for ecosystems in the fynbos biome. The models are planned to run on a portable desktop computer with 500 kbytes of memory, extended BASIC language...
A Model Management Approach for Co-Simulation Model Evaluation
Zhang, X.C.; Broenink, Johannes F.; Filipe, Joaquim; Kacprzyk, Janusz; Pina, Nuno
2011-01-01
Simulating formal models is a common means for validating the correctness of the system design and reduce the time-to-market. In most of the embedded control system design, multiple engineering disciplines and various domain-specific models are often involved, such as mechanical, control, software
eShopper modeling and simulation
Petrushin, Valery A.
2001-03-01
The advent of e-commerce gives an opportunity to shift the paradigm of customer communication into a highly interactive mode. The new generation of commercial Web servers, such as the Blue Martini's server, combines the collection of data on a customer behavior with real-time processing and dynamic tailoring of a feedback page. The new opportunities for direct product marketing and cross selling are arriving. The key problem is what kind of information do we need to achieve these goals, or in other words, how do we model the customer? The paper is devoted to customer modeling and simulation. The focus is on modeling an individual customer. The model is based on the customer's transaction data, click stream data, and demographics. The model includes the hierarchical profile of a customer's preferences to different types of products and brands; consumption models for the different types of products; the current focus, trends, and stochastic models for time intervals between purchases; product affinity models; and some generalized features, such as purchasing power, sensitivity to advertising, price sensitivity, etc. This type of model is used for predicting the date of the next visit, overall spending, and spending for different types of products and brands. For some type of stores (for example, a supermarket) and stable customers, it is possible to forecast the shopping lists rather accurately. The forecasting techniques are discussed. The forecasting results can be used for on- line direct marketing, customer retention, and inventory management. The customer model can also be used as a generative model for simulating the customer's purchasing behavior in different situations and for estimating customer's features.
NUMERICAL MODEL APPLICATION IN ROWING SIMULATOR DESIGN
Directory of Open Access Journals (Sweden)
Petr Chmátal
2016-04-01
Full Text Available The aim of the research was to carry out a hydraulic design of rowing/sculling and paddling simulator. Nowadays there are two main approaches in the simulator design. The first one includes a static water with no artificial movement and counts on specially cut oars to provide the same resistance in the water. The second approach, on the other hand uses pumps or similar devices to force the water to circulate but both of the designs share many problems. Such problems are affecting already built facilities and can be summarized as unrealistic feeling, unwanted turbulent flow and bad velocity profile. Therefore, the goal was to design a new rowing simulator that would provide nature-like conditions for the racers and provide an unmatched experience. In order to accomplish this challenge, it was decided to use in-depth numerical modeling to solve the hydraulic problems. The general measures for the design were taken in accordance with space availability of the simulator ́s housing. The entire research was coordinated with other stages of the construction using BIM. The detailed geometry was designed using a numerical model in Ansys Fluent and parametric auto-optimization tools which led to minimum negative hydraulic phenomena and decreased investment and operational costs due to the decreased hydraulic losses in the system.
Energy Technology Data Exchange (ETDEWEB)
Cester, Francesco; Deitenbeck, Helmuth; Kuentzel, Matthias; Scheuer, Josef; Voggenberger, Thomas
2015-04-15
The overall objective of the project is to develop a general simulation environment for program systems used in reactor safety analysis. The simulation environment provides methods for graphical modeling and evaluation of results for the simulation models. The terms of graphical modeling and evaluation of results summarize computerized methods of pre- and postprocessing for the simulation models, which can assist the user in the execution of the simulation steps. The methods comprise CAD (''Computer Aided Design'') based input tools, interactive user interfaces for the execution of the simulation and the graphical representation and visualization of the simulation results. A particular focus was set on the requirements of the system code ATHLET. A CAD tool was developed that allows the specification of 3D geometry of the plant components and the discretization with a simulation grid. The system provides inter-faces to generate the input data of the codes and to export the data for the visualization software. The CAD system was applied for the modeling of a cooling circuit and reactor pressure vessel of a PWR. For the modeling of complex systems with many components, a general purpose graphical network editor was adapted and expanded. The editor is able to simulate networks with complex topology graphically by suitable building blocks. The network editor has been enhanced and adapted to the modeling of balance of plant and thermal fluid systems in ATHLET. For the visual display of the simulation results in the local context of the 3D geometry and the simulation grid, the open source program ParaView is applied, which is widely used for 3D visualization of field data, offering multiple options for displaying and ana-lyzing the data. New methods were developed, that allow the necessary conversion of the results of the reactor safety codes and the data of the CAD models. The trans-formed data may then be imported into ParaView and visualized. The
Advanced Modeling, Simulation and Analysis (AMSA) Capability Roadmap Progress Review
Antonsson, Erik; Gombosi, Tamas
2005-01-01
Contents include the following: NASA capability roadmap activity. Advanced modeling, simulation, and analysis overview. Scientific modeling and simulation. Operations modeling. Multi-special sensing (UV-gamma). System integration. M and S Environments and Infrastructure.
Macro Level Simulation Model Of Space Shuttle Processing
2000-01-01
The contents include: 1) Space Shuttle Processing Simulation Model; 2) Knowledge Acquisition; 3) Simulation Input Analysis; 4) Model Applications in Current Shuttle Environment; and 5) Model Applications for Future Reusable Launch Vehicles (RLV's). This paper is presented in viewgraph form.
Interactive Modelling and Simulation of Human Motion
DEFF Research Database (Denmark)
Engell-Nørregård, Morten Pol
Dansk resumé Denne ph.d.-afhandling beskæftiger sig med modellering og simulation af menneskelig bevægelse. Emnerne i denne afhandling har mindst to ting til fælles. For det første beskæftiger de sig med menneskelig bevægelse. Selv om de udviklede modeller også kan benyttes til andre ting,er det ....... Endvidere kan den anvendes med enhver softbody simuleringsmodel som finite elements eller mass spring systemer. • En kontrol metode til deformerbare legemer baseret på rum tids opti- mering. fremgangsmåden kan anvendes til at styre sammentrækning af muskler i en muskel simulering....
Computer Modelling and Simulation for Inventory Control
Directory of Open Access Journals (Sweden)
G.K. Adegoke
2012-07-01
Full Text Available This study concerns the role of computer simulation as a device for conducting scientific experiments on inventory control. The stores function utilizes a bulk of physical assets and engages a bulk of financial resources in a manufacturing outfit therefore there is a need for an efficient inventory control. The reason being that inventory control reduces cost of production and thereby facilitates the effective and efficient accomplishment of production objectives of an organization. Some mathematical and statistical models were used to compute the Economic Order Quantity (EOQ. Test data were gotten from a manufacturing company and same were simulated. The results generated were used to predict a real life situation and have been presented and discussed. The language of implementation for the three models is Turbo Pascal due to its capability, generality and flexibility as a scientific programming language.
Model parameters for simulation of physiological lipids
McGlinchey, Nicholas
2016-01-01
Coarse grain simulation of proteins in their physiological membrane environment can offer insight across timescales, but requires a comprehensive force field. Parameters are explored for multicomponent bilayers composed of unsaturated lipids DOPC and DOPE, mixed‐chain saturation POPC and POPE, and anionic lipids found in bacteria: POPG and cardiolipin. A nonbond representation obtained from multiscale force matching is adapted for these lipids and combined with an improved bonding description of cholesterol. Equilibrating the area per lipid yields robust bilayer simulations and properties for common lipid mixtures with the exception of pure DOPE, which has a known tendency to form nonlamellar phase. The models maintain consistency with an existing lipid–protein interaction model, making the force field of general utility for studying membrane proteins in physiologically representative bilayers. © 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc. PMID:26864972
Computerized Systems: Centralized or Decentralized?
Seitz, Linda Ludington
1985-01-01
Computerized management information systems have long been used in business, and data integration and sophisticated programing now enable many businesses to decentralize their information operations. This approach has advantages and disadvantages that colleges and universities must weigh and plan for carefully. (MSE)
Theory, Modeling and Simulation Annual Report 2000
Energy Technology Data Exchange (ETDEWEB)
Dixon, David A.; Garrett, Bruce C.; Straatsma, Tp; Jones, Donald R.; Studham, Ronald S.; Harrison, Robert J.; Nichols, Jeffrey A.
2001-11-01
This annual report describes the 2000 research accomplishments for the Theory, Modeling, and Simulation (TM&S) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment to providing world-class experimental, theoretical, and computational capabilities for solving the nation's environmental problems.
Theory, Modeling and Simulation Annual Report 2000
Energy Technology Data Exchange (ETDEWEB)
Dixon, David A; Garrett, Bruce C; Straatsma, TP; Jones, Donald R; Studham, Scott; Harrison, Robert J; Nichols, Jeffrey A
2001-11-01
This annual report describes the 2000 research accomplishments for the Theory, Modeling, and Simulation (TM and S) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment to providing world-class experimental, theoretical, and computational capabilities for solving the nation's environmental problems.
Catalog of Wargaming and Military Simulation Models
1992-02-07
PROPONENT: USAF ASD, McDonnell Douglas Corp. POINT OF CONTACT: Photon Research Associates (Alias): Mr. Jeff Johnson , (619) 455-9741; McDonnell Douglas...POINTOF CONTACT: Dr. R. Johnson , (DSN) 295-1593 or (301) 295-1593. PURPOSE: The model provides simulation of airland activities in a theater of operations...training, and education. PROPONENT: J-8 Political Military Affairs Directorate. POINT OF CONTACT: LTC Steven G. Stainer . PURPOSE: RDSS is a system
Fully Adaptive Radar Modeling and Simulation Development
2017-04-01
Organization (NATO) Sensors Electronics Technology (SET)-227 Panel on Cognitive Radar. The FAR M&S architecture developed in Phase I allows for...Air Force’s previously developed radar M&S tools. This report is organized as follows. In Chapter 3, we provide an overview of the FAR framework...AFRL-RY-WP-TR-2017-0074 FULLY ADAPTIVE RADAR MODELING AND SIMULATION DEVELOPMENT Kristine L. Bell and Anthony Kellems Metron, Inc
Difficulties with True Interoperability in Modeling & Simulation
2011-12-01
Standards in M&S cover multiple layers of technical abstraction. There are middleware specifica- tions, such as the High Level Architecture (HLA) ( IEEE Xplore ... IEEE Xplore Digital Library. 2010. 1516-2010 IEEE Standard for Modeling and Simulation (M&S) High Level Architecture (HLA) – Framework and Rules...using different communication protocols being able to allow da- 2642978-1-4577-2109-0/11/$26.00 ©2011 IEEE Report Documentation Page Form ApprovedOMB No
Modelling interplanetary CMEs using magnetohydrodynamic simulations
Directory of Open Access Journals (Sweden)
P. J. Cargill
Full Text Available The dynamics of Interplanetary Coronal Mass Ejections (ICMEs are discussed from the viewpoint of numerical modelling. Hydrodynamic models are shown to give a good zero-order picture of the plasma properties of ICMEs, but they cannot model the important magnetic field effects. Results from MHD simulations are shown for a number of cases of interest. It is demonstrated that the strong interaction of the ICME with the solar wind leads to the ICME and solar wind velocities being close to each other at 1 AU, despite their having very different speeds near the Sun. It is also pointed out that this interaction leads to a distortion of the ICME geometry, making cylindrical symmetry a dubious assumption for the CME field at 1 AU. In the presence of a significant solar wind magnetic field, the magnetic fields of the ICME and solar wind can reconnect with each other, leading to an ICME that has solar wind-like field lines. This effect is especially important when an ICME with the right sense of rotation propagates down the heliospheric current sheet. It is also noted that a lack of knowledge of the coronal magnetic field makes such simulations of little use in space weather forecasts that require knowledge of the ICME magnetic field strength.
Key words. Interplanetary physics (interplanetary magnetic fields Solar physics, astrophysics, and astronomy (flares and mass ejections Space plasma physics (numerical simulation studies
Interactive Modelling and Simulation of Human Motion
DEFF Research Database (Denmark)
Engell-Nørregård, Morten Pol
Dansk resumé Denne ph.d.-afhandling beskæftiger sig med modellering og simulation af menneskelig bevægelse. Emnerne i denne afhandling har mindst to ting til fælles. For det første beskæftiger de sig med menneskelig bevægelse. Selv om de udviklede modeller også kan benyttes til andre ting,er det...... menneskers led, der udviser både ikke-konveksitet og flere frihedsgrader • En generel og alsidig model for aktivering af bløde legemer. Modellen kan anvendes som et animations værktøj, men er lige så velegnet til simulering af menneskelige muskler, da den opfylder de grundlæggende fysiske principper...... primære fokus på at modellere den menneskelige krop. For det andet, beskæftiger de sig alle med simulering som et redskab til at syntetisere bevægelse og dermed skabe animationer. Dette er en vigtigt pointe, da det betyder, at vi ikke kun skaber værktøjer til animatorer, som de kan bruge til at lave sjove...
WiBro Mobility Simulation Model
Directory of Open Access Journals (Sweden)
Junaid Qayyum
2011-09-01
Full Text Available WiBro, or Wireless Broadband, is the newest variety of mobile wireless broadband access. WiBro technology is being developed by the Korean Telecoms industry. It is based on the IEEE 802.16e (Mobile WiMax international standard. Korean based fixed-line operators KT, SK Telecom were the first to get the licenses by the South Korean government to provide WiBro Commercially. Samsung had a demonstration on WiBro Mobile Phones and Systems at the "APEC IT Exhibition 2006". WiBro is comprised of two phases namely WiBro Phase I and WiBro Phase II. Samsung Electronics has been extensively contributing to Koreas WiBro (Wireless Broadband initiative as well as the IEEE 802.16 standards. The WiBro is a specific subset of the 802.16 standards, specially focusing on supporting full mobility of wireless access systems with OFDMA PHY interface. In this work, we have developed a simulation model of the WiBro system consisting of a set of Base Stations and Mobile Subscriber Stations by using the OPNET Modeler. The simulation model has been utilized to evaluate effective MAC layer throughput, resource usage efficiency, QoS class differentiation, and system capacity and performance under various simulation scenarios.
Progress in Modeling and Simulation of Batteries
Energy Technology Data Exchange (ETDEWEB)
Turner, John A [ORNL
2016-01-01
Modeling and simulation of batteries, in conjunction with theory and experiment, are important research tools that offer opportunities for advancement of technologies that are critical to electric motors. The development of data from the application of these tools can provide the basis for managerial and technical decision-making. Together, these will continue to transform batteries for electric vehicles. This collection of nine papers presents the modeling and simulation of batteries and the continuing contribution being made to this impressive progress, including topics that cover: * Thermal behavior and characteristics * Battery management system design and analysis * Moderately high-fidelity 3D capabilities * Optimization Techniques and Durability As electric vehicles continue to gain interest from manufacturers and consumers alike, improvements in economy and affordability, as well as adoption of alternative fuel sources to meet government mandates are driving battery research and development. Progress in modeling and simulation will continue to contribute to battery improvements that deliver increased power, energy storage, and durability to further enhance the appeal of electric vehicles.
Directory of Open Access Journals (Sweden)
Leonardo Leiderman
1992-03-01
Full Text Available Simulating an Optimizing Model of Currency Substitution This paper reports simulations based on the parameter estimates of an intertemporal model of currency substitution under nonexpected utility obtained by Bufman and Leiderman (1991. Here we first study the quantitative impact of changes in the degree of dollarization and in the elasticity of currency substitution on government seigniorage. Then, when examine whether the model can account for the comovement of consumption growth and assets' returnr after the 1985 stabilization program, and in particular for the consumption boom of 1986-87. The results are generally encouraging for future applications of optimizing models of currencysubstitution to policy and practical issues.
Computer Models Simulate Fine Particle Dispersion
2010-01-01
Through a NASA Seed Fund partnership with DEM Solutions Inc., of Lebanon, New Hampshire, scientists at Kennedy Space Center refined existing software to study the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces. The software, EDEM, allows users to import particles and obtain accurate representations of their shapes for modeling purposes, such as simulating bulk solids behavior, and was enhanced to be able to more accurately model fine, abrasive, cohesive particles. These new EDEM capabilities can be applied in many industries unrelated to space exploration and have been adopted by several prominent U.S. companies, including John Deere, Pfizer, and Procter & Gamble.
Consolidation modelling for thermoplastic composites forming simulation
Xiong, H.; Rusanov, A.; Hamila, N.; Boisse, P.
2016-10-01
Pre-impregnated thermoplastic composites are widely used in the aerospace industry for their excellent mechanical properties, Thermoforming thermoplastic prepregs is a fast manufacturing process, the automotive industry has shown increasing interest in this manufacturing processes, in which the reconsolidation is an essential stage. The model of intimate contact is investigated as the consolidation model, compression experiments have been launched to identify the material parameters, several numerical tests show the influents of the temperature and pressure applied during processing. Finally, a new solid-shell prismatic element has been presented for the simulation of consolidation step in the thermoplastic composites forming process.
Modeling and simulation of reactive flows
Bortoli, De AL; Pereira, Felipe
2015-01-01
Modelling and Simulation of Reactive Flows presents information on modeling and how to numerically solve reactive flows. The book offers a distinctive approach that combines diffusion flames and geochemical flow problems, providing users with a comprehensive resource that bridges the gap for scientists, engineers, and the industry. Specifically, the book looks at the basic concepts related to reaction rates, chemical kinetics, and the development of reduced kinetic mechanisms. It considers the most common methods used in practical situations, along with equations for reactive flows, and va
Solar Electric Bicycle Body Modeling and Simulation
Directory of Open Access Journals (Sweden)
Zhikun Wang
2013-10-01
Full Text Available A new solar electric bicycle design and study were carried out on in this paper. Application of CAD technology to establish three-dimension geometric model, using the kinetic analysis on the frame and other parts for numerical simulation and static strength analysis for the vehicle model design, virtual assembly, complete frame dynamics analysis and vibration analysis, with considering other factors, first on the frame structure improvement, second on security of design calculation analysis and comparison, finally get the ideal body design.
Viscoelastic flow simulations in model porous media
De, S.; Kuipers, J. A. M.; Peters, E. A. J. F.; Padding, J. T.
2017-05-01
We investigate the flow of unsteadfy three-dimensional viscoelastic fluid through an array of symmetric and asymmetric sets of cylinders constituting a model porous medium. The simulations are performed using a finite-volume methodology with a staggered grid. The solid-fluid interfaces of the porous structure are modeled using a second-order immersed boundary method [S. De et al., J. Non-Newtonian Fluid Mech. 232, 67 (2016), 10.1016/j.jnnfm.2016.04.002]. A finitely extensible nonlinear elastic constitutive model with Peterlin closure is used to model the viscoelastic part. By means of periodic boundary conditions, we model the flow behavior for a Newtonian as well as a viscoelastic fluid through successive contractions and expansions. We observe the presence of counterrotating vortices in the dead ends of our geometry. The simulations provide detailed insight into how flow structure, viscoelastic stresses, and viscoelastic work change with increasing Deborah number De. We observe completely different flow structures and different distributions of the viscoelastic work at high De in the symmetric and asymmetric configurations, even though they have the exact same porosity. Moreover, we find that even for the symmetric contraction-expansion flow, most energy dissipation is occurring in shear-dominated regions of the flow domain, not in extensional-flow-dominated regions.
LISP based simulation generators for modeling complex space processes
Tseng, Fan T.; Schroer, Bernard J.; Dwan, Wen-Shing
1987-01-01
The development of a simulation assistant for modeling discrete event processes is presented. Included are an overview of the system, a description of the simulation generators, and a sample process generated using the simulation assistant.
Biomedical Simulation Models of Human Auditory Processes
Bicak, Mehmet M. A.
2012-01-01
Detailed acoustic engineering models that explore noise propagation mechanisms associated with noise attenuation and transmission paths created when using hearing protectors such as earplugs and headsets in high noise environments. Biomedical finite element (FE) models are developed based on volume Computed Tomography scan data which provides explicit external ear, ear canal, middle ear ossicular bones and cochlea geometry. Results from these studies have enabled a greater understanding of hearing protector to flesh dynamics as well as prioritizing noise propagation mechanisms. Prioritization of noise mechanisms can form an essential framework for exploration of new design principles and methods in both earplug and earcup applications. These models are currently being used in development of a novel hearing protection evaluation system that can provide experimentally correlated psychoacoustic noise attenuation. Moreover, these FE models can be used to simulate the effects of blast related impulse noise on human auditory mechanisms and brain tissue.
Simulation Model of Brushless Excitation System
Directory of Open Access Journals (Sweden)
Ahmed N.A. Alla
2007-01-01
Full Text Available Excitation system is key element in the dynamic performance of electric power systems, accurate excitation models are of great importance in simulating and investigating the power system transient phenomena. Parameter identification of the Brushless excitation system was presented. First a block diagram for the EXS parameter was proposed based on the documents and maps in the power station. To identify the parameters of this model, a test procedure to obtain step response, was presented. Using the Genetic Algorithm with the Matlab-software it was possible to identify all the necessary parameters of the model. Using the same measured input signals the response from the standard model showed nearly the same behavior as the excitation system.
Modeling and simulation of direct contact evaporators
Directory of Open Access Journals (Sweden)
F.B. Campos
2001-09-01
Full Text Available A dynamic model of a direct contact evaporator was developed and coupled to a recently developed superheated bubble model. The latter model takes into account heat and mass transfer during the bubble formation and ascension stages and is able to predict gas holdup in nonisothermal systems. The results of the coupled model, which does not have any adjustable parameter, were compared with experimental data. The transient behavior of the liquid-phase temperature and the vaporization rate under quasi-steady-state conditions were in very good agreement with experimental data. The transient behavior of liquid height was only reasonably simulated. In order to explain this partial disagreement, some possible causes were analyzed.
Efficient Turbulence Modeling for CFD Wake Simulations
DEFF Research Database (Denmark)
van der Laan, Paul
, that can accurately and efficiently simulate wind turbine wakes. The linear k-ε eddy viscosity model (EVM) is a popular turbulence model in RANS; however, it underpredicts the velocity wake deficit and cannot predict the anisotropic Reynolds-stresses in the wake. In the current work, nonlinear eddy...... viscosity models (NLEVM) are applied to wind turbine wakes. NLEVMs can model anisotropic turbulence through a nonlinear stress-strain relation, and they can improve the velocity deficit by the use of a variable eddy viscosity coefficient, that delays the wake recovery. Unfortunately, all tested NLEVMs show...... numerically unstable behavior for fine grids, which inhibits a grid dependency study for numerical verification. Therefore, a simpler EVM is proposed, labeled as the k-ε - fp EVM, that has a linear stress-strain relation, but still has a variable eddy viscosity coefficient. The k-ε - fp EVM is numerically...
Another Route to a General Theory of Cultural Transmission: A Systems Model
Dobbert, Marion L.
1975-01-01
A cultural transmission theory is presented. The model has two uses: to provide a guide for gathering cultural transmission data; and to set up a computerized cultural transmission simulation. Availability information is given in SO 504 073. (Author/RM)
Integrating Visualizations into Modeling NEST Simulations.
Nowke, Christian; Zielasko, Daniel; Weyers, Benjamin; Peyser, Alexander; Hentschel, Bernd; Kuhlen, Torsten W
2015-01-01
Modeling large-scale spiking neural networks showing realistic biological behavior in their dynamics is a complex and tedious task. Since these networks consist of millions of interconnected neurons, their simulation produces an immense amount of data. In recent years it has become possible to simulate even larger networks. However, solutions to assist researchers in understanding the simulation's complex emergent behavior by means of visualization are still lacking. While developing tools to partially fill this gap, we encountered the challenge to integrate these tools easily into the neuroscientists' daily workflow. To understand what makes this so challenging, we looked into the workflows of our collaborators and analyzed how they use the visualizations to solve their daily problems. We identified two major issues: first, the analysis process can rapidly change focus which requires to switch the visualization tool that assists in the current problem domain. Second, because of the heterogeneous data that results from simulations, researchers want to relate data to investigate these effectively. Since a monolithic application model, processing and visualizing all data modalities and reflecting all combinations of possible workflows in a holistic way, is most likely impossible to develop and to maintain, a software architecture that offers specialized visualization tools that run simultaneously and can be linked together to reflect the current workflow, is a more feasible approach. To this end, we have developed a software architecture that allows neuroscientists to integrate visualization tools more closely into the modeling tasks. In addition, it forms the basis for semantic linking of different visualizations to reflect the current workflow. In this paper, we present this architecture and substantiate the usefulness of our approach by common use cases we encountered in our collaborative work.
Integrating Visualizations into Modeling NEST Simulations
Directory of Open Access Journals (Sweden)
Christian eNowke
2015-12-01
Full Text Available Modeling large-scale spiking neural networks showing realistic biological behavior in their dynamics is a complex and tedious task. Since these networks consist of millions of interconnected neurons, their simulation produces an immense amount of data. In recent years it has become possible to simulate even larger networks. However, solutions to assist researchers in understanding the simulation's complex emergent behavior by means of visualization are still lacking. While developing tools to partially fill this gap, we encountered the challenge to integrate these tools easily into the neuroscientists' daily workflow. To understand what makes this so challenging, we looked into the workflows of our collaborators and analyzed how they use the visualizations to solve their daily problems. We identified two major issues: first, the analysis process can rapidly change focus which requires to switch the visualization tool that assists in the current problem domain. Second, because of the heterogeneous data that results from simulations, researchers want to relate data to investigate these effectively. Since a monolithic application model, processing and visualizing all data modalities and reflecting all combinations of possible workflows in a holistic way, is most likely impossible to develop and to maintain, a software architecture that offers specialized visualization tools that run simultaneously and can be linked together to reflect the current workflow, is a more feasible approach. To this end, we have developed a software architecture that allows neuroscientists to integrate visualization tools more closely into the modeling tasks. In addition, it forms the basis for semantic linking of different visualizations to reflect the current workflow. In this paper, we present this architecture and substantiate the usefulness of our approach by common use cases we encountered in our collaborative work.
M.R. Baye (Michael); A. Gilette (Ann); C.G. de Vries (Casper)
1994-01-01
textabstractWe analyze the existence of equilibrium in an asset market under asymmetric information. Price formation is modeled as a bilateral sealed bid auction where uninformed and informed traders submit limit orders to a computerized specialist. The computerized specialist is programmed to sell
Simulation modeling for microbial risk assessment.
Cassin, M H; Paoli, G M; Lammerding, A M
1998-11-01
Quantitative microbial risk assessment implies an estimation of the probability and impact of adverse health outcomes due to microbial hazards. In the case of food safety, the probability of human illness is a complex function of the variability of many parameters that influence the microbial environment, from the production to the consumption of a food. The analytical integration required to estimate the probability of foodborne illness is intractable in all but the simplest of models. Monte Carlo simulation is an alternative to computing analytical solutions. In some cases, a risk assessment may be commissioned to serve a larger purpose than simply the estimation of risk. A Monte Carlo simulation can provide insights into complex processes that are invaluable, and otherwise unavailable, to those charged with the task of risk management. Using examples from a farm-to-fork model of the fate of Escherichia coli O157:H7 in ground beef hamburgers, this paper describes specifically how such goals as research prioritization, risk-based characterization of control points, and risk-based comparison of intervention strategies can be objectively achieved using Monte Carlo simulation.
Application of simulation models for the optimization of business processes
Jašek, Roman; Sedláček, Michal; Chramcov, Bronislav; Dvořák, Jiří
2016-06-01
The paper deals with the applications of modeling and simulation tools in the optimization of business processes, especially in solving an optimization of signal flow in security company. As a modeling tool was selected Simul8 software that is used to process modeling based on discrete event simulation and which enables the creation of a visual model of production and distribution processes.
Raytracing simulations of coupled dark energy models
Pace, Francesco; Moscardini, Lauro; Bacon, David; Crittenden, Robert
2014-01-01
Dark matter and dark energy are usually assumed to be independent, coupling only gravitationally. An extension to this simple picture is to model dark energy as a scalar field which is directly coupled to the cold dark matter fluid. Such a non-trivial coupling in the dark sector leads to a fifth force and a time-dependent dark matter particle mass. In this work we examine the impact that dark energy-dark matter couplings have on weak lensing statistics by constructing realistic simulated weak-lensing maps using raytracing techniques through a suite of N-body cosmological simulations. We construct maps for an array of different lensing quantities, covering a range of scales from a few arcminutes to several degrees. The concordance $\\Lambda$CDM model is compared to different coupled dark energy models, described either by an exponential scalar field potential (standard coupled dark energy scenario) or by a SUGRA potential (bouncing model). We analyse several statistical quantities, in particular the power spect...
Closed loop models for analyzing engineering requirements for simulators
Baron, S.; Muralidharan, R.; Kleinman, D.
1980-01-01
A closed loop analytic model, incorporating a model for the human pilot, (namely, the optimal control model) that would allow certain simulation design tradeoffs to be evaluated quantitatively was developed. This model was applied to a realistic flight control problem. The resulting model is used to analyze both overall simulation effects and the effects of individual elements. The results show that, as compared to an ideal continuous simulation, the discrete simulation can result in significant performance and/or workload penalties.
Induction generator models in dynamic simulation tools
DEFF Research Database (Denmark)
Knudsen, Hans; Akhmatov, Vladislav
1999-01-01
For AC network with large amount of induction generators (windmills) the paper demonstrates a significant discrepancy in the simulated voltage recovery after fault in weak networks when comparing dynamic and transient stability descriptions and the reasons of discrepancies are explained. It is fo......For AC network with large amount of induction generators (windmills) the paper demonstrates a significant discrepancy in the simulated voltage recovery after fault in weak networks when comparing dynamic and transient stability descriptions and the reasons of discrepancies are explained....... It is found to be possible to include a transient model in dynamic stability tools and, then, obtain correct results also in dynamic tools. The representation of the rotating system influences on the voltage recovery shape which is an important observation in case of windmills, where a heavy mill is connected...
Galaxy alignments: Theory, modelling and simulations
Kiessling, Alina; Joachimi, Benjamin; Kirk, Donnacha; Kitching, Thomas D; Leonard, Adrienne; Mandelbaum, Rachel; Schäfer, Björn Malte; Sifón, Cristóbal; Brown, Michael L; Rassat, Anais
2015-01-01
The shapes of galaxies are not randomly oriented on the sky. During the galaxy formation and evolution process, environment has a strong influence, as tidal gravitational fields in large-scale structure tend to align the shapes and angular momenta of nearby galaxies. Additionally, events such as galaxy mergers affect the relative alignments of galaxies throughout their history. These "intrinsic galaxy alignments" are known to exist, but are still poorly understood. This review will offer a pedagogical introduction to the current theories that describe intrinsic galaxy alignments, including the apparent difference in intrinsic alignment between early- and late-type galaxies and the latest efforts to model them analytically. It will then describe the ongoing efforts to simulate intrinsic alignments using both $N$-body and hydrodynamic simulations. Due to the relative youth of this field, there is still much to be done to understand intrinsic galaxy alignments and this review summarises the current state of the ...
A Simulation Model for Component Commonality
Institute of Scientific and Technical Information of China (English)
ZHU Xiao-chi; ZHANG Zi-gang
2002-01-01
Component commonality has been cited as a powerful approach for manufacturers to cope with increased component proliferation and to control inventory costs. To fully realize its potential benefits, one needs a clear understanding of its impacts on the system. In this paper, the feasibility of using a simulation model to provide a systematic perspective for manufacturing firms to implement a commonality strategy is demonstrated. Alternative commonality strategies including the stage of employing commonality and the allocation policies are simulated. Several interesting results on effects of commonality, allocation policies,and optimal solutions are obtained. We then summarize qualitative insights and managerial implications into the component commonality design and implementation, and inventory management in a general multi-stage assembly system.
Assumed PDF modeling in rocket combustor simulations
Lempke, M.; Gerlinger, P.; Aigner, M.
2013-03-01
In order to account for the interaction between turbulence and chemistry, a multivariate assumed PDF (Probability Density Function) approach is used to simulate a model rocket combustor with finite-rate chemistry. The reported test case is the PennState preburner combustor with a single shear coaxial injector. Experimental data for the wall heat flux is available for this configuration. Unsteady RANS (Reynolds-averaged Navier-Stokes) simulation results with and without the assumed PDF approach are analyzed and compared with the experimental data. Both calculations show a good agreement with the experimental wall heat flux data. Significant changes due to the utilization of the assumed PDF approach can be observed in the radicals, e. g., the OH mass fraction distribution, while the effect on the wall heat flux is insignificant.
Traffic flow dynamics data, models and simulation
Treiber, Martin
2013-01-01
This textbook provides a comprehensive and instructive coverage of vehicular traffic flow dynamics and modeling. It makes this fascinating interdisciplinary topic, which to date was only documented in parts by specialized monographs, accessible to a broad readership. Numerous figures and problems with solutions help the reader to quickly understand and practice the presented concepts. This book is targeted at students of physics and traffic engineering and, more generally, also at students and professionals in computer science, mathematics, and interdisciplinary topics. It also offers material for project work in programming and simulation at college and university level. The main part, after presenting different categories of traffic data, is devoted to a mathematical description of the dynamics of traffic flow, covering macroscopic models which describe traffic in terms of density, as well as microscopic many-particle models in which each particle corresponds to a vehicle and its driver. Focus chapters on ...
Biomechanics trends in modeling and simulation
Ogden, Ray
2017-01-01
The book presents a state-of-the-art overview of biomechanical and mechanobiological modeling and simulation of soft biological tissues. Seven well-known scientists working in that particular field discuss topics such as biomolecules, networks and cells as well as failure, multi-scale, agent-based, bio-chemo-mechanical and finite element models appropriate for computational analysis. Applications include arteries, the heart, vascular stents and valve implants as well as adipose, brain, collagenous and engineered tissues. The mechanics of the whole cell and sub-cellular components as well as the extracellular matrix structure and mechanotransduction are described. In particular, the formation and remodeling of stress fibers, cytoskeletal contractility, cell adhesion and the mechanical regulation of fibroblast migration in healing myocardial infarcts are discussed. The essential ingredients of continuum mechanics are provided. Constitutive models of fiber-reinforced materials with an emphasis on arterial walls ...
Hierarchical Boltzmann simulations and model error estimation
Torrilhon, Manuel; Sarna, Neeraj
2017-08-01
A hierarchical simulation approach for Boltzmann's equation should provide a single numerical framework in which a coarse representation can be used to compute gas flows as accurately and efficiently as in computational fluid dynamics, but a subsequent refinement allows to successively improve the result to the complete Boltzmann result. We use Hermite discretization, or moment equations, for the steady linearized Boltzmann equation for a proof-of-concept of such a framework. All representations of the hierarchy are rotationally invariant and the numerical method is formulated on fully unstructured triangular and quadrilateral meshes using a implicit discontinuous Galerkin formulation. We demonstrate the performance of the numerical method on model problems which in particular highlights the relevance of stability of boundary conditions on curved domains. The hierarchical nature of the method allows also to provide model error estimates by comparing subsequent representations. We present various model errors for a flow through a curved channel with obstacles.
Modelling and Simulation for Major Incidents
Directory of Open Access Journals (Sweden)
Eleonora Pacciani
2015-11-01
Full Text Available In recent years, there has been a rise in Major Incidents with big impact on the citizens health and the society. Without the possibility of conducting live experiments when it comes to physical and/or toxic trauma, only an accurate in silico reconstruction allows us to identify organizational solutions with the best possible chance of success, in correlation with the limitations on available resources (e.g. medical team, first responders, treatments, transports, and hospitals availability and with the variability of the characteristic of event (e.g. type of incident, severity of the event and type of lesions. Utilizing modelling and simulation techniques, a simplified mathematical model of physiological evolution for patients involved in physical and toxic trauma incident scenarios has been developed and implemented. The model formalizes the dynamics, operating standards and practices of medical response and the main emergency service in the chain of emergency management during a Major Incident.
Vertical eddy heat fluxes from model simulations
Stone, Peter H.; Yao, Mao-Sung
1991-01-01
Vertical eddy fluxes of heat are calculated from simulations with a variety of climate models, ranging from three-dimensional GCMs to a one-dimensional radiative-convective model. The models' total eddy flux in the lower troposphere is found to agree well with Hantel's analysis from observations, but in the mid and upper troposphere the models' values are systematically 30 percent to 50 percent smaller than Hantel's. The models nevertheless give very good results for the global temperature profile, and the reason for the discrepancy is unclear. The model results show that the manner in which the vertical eddy flux is carried is very sensitive to the parameterization of moist convection. When a moist adiabatic adjustment scheme with a critical value for the relative humidity of 100 percent is used, the vertical transports by large-scale eddies and small-scale convection on a global basis are equal: but when a penetrative convection scheme is used, the large-scale flux on a global basis is only about one-fifth to one-fourth the small-scale flux. Comparison of the model results with observations indicates that the results with the latter scheme are more realistic. However, even in this case, in mid and high latitudes the large and small-scale vertical eddy fluxes of heat are comparable in magnitude above the planetary boundary layer.
Heinrich events modeled in transient glacial simulations
Ziemen, Florian; Kapsch, Marie; Mikolajewicz, Uwe
2017-04-01
Heinrich events are among the most prominent events of climate variability recorded in proxies across the northern hemisphere. They are the archetype of ice sheet — climate interactions on millennial time scales. Nevertheless, the exact mechanisms that cause Heinrich events are still under debate, and their climatic consequences are far from being fully understood. We address open questions by studying Heinrich events in a coupled ice sheet model (ISM) atmosphere-ocean-vegetation general circulation model (AOVGCM) framework, where this variability occurs as part of the model generated internal variability. The framework consists of a northern hemisphere setup of the modified Parallel Ice Sheet Model (mPISM) coupled to the global AOVGCM ECHAM5/MPIOM/LPJ. The simulations were performed fully coupled and with transient orbital and greenhouse gas forcing. They span from several millennia before the last glacial maximum into the deglaciation. To make these long simulations feasible, the atmosphere is accelerated by a factor of 10 relative to the other model components using a periodical-synchronous coupling technique. To disentangle effects of the Heinrich events and the deglaciation, we focus on the events occurring before the deglaciation. The modeled Heinrich events show a peak ice discharge of about 0.05 Sv and raise the sea level by 2.3 m on average. The resulting surface water freshening reduces the Atlantic meridional overturning circulation and ocean heat release. The reduction in ocean heat release causes a sub-surface warming and decreases the air temperature and precipitation regionally and downstream into Eurasia. The surface elevation decrease of the ice sheet enhances moisture transport onto the ice sheet and thus increases precipitation over the Hudson Bay area, thereby accelerating the recovery after an event.
Modeling and Simulation. III. Simulation of a Model for Development of Visual Cortical Specificity.
1986-12-15
of parameter values. Experiment, model, and simulation 5’ The simulations we consider mimic, in form, classic deprivation experiments. Kittens are...second paper of the series (ref. 8) reviews the results of numerous experiments on the neuronal development of kitten visual cortex. We have...restricted to a very limited range of oriented contours (see citations in ref. 8). Kittens were raised, for example, viewing only horizontal or only vertical
An Agent-Based Monetary Production Simulation Model
DEFF Research Database (Denmark)
Bruun, Charlotte
2006-01-01
An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable......An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable...
An Agent-Based Monetary Production Simulation Model
DEFF Research Database (Denmark)
Bruun, Charlotte
2006-01-01
An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable......An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable...
Documentation of Nursing Practice Using a Computerized Medical Information System
Romano, Carol
1981-01-01
This paper discusses a definition of the content of the computerized nursing data base developed by the Nursing Department for the Clinical Center Medical Information System at the National Institutes of Health in Bethesda, Maryland. The author describes the theoretical framework for the content and presents a model to describe the organization of the nursing data components in relation to the process of nursing care delivery. Nursing documentation requirements of Nurse Practice Acts, American Nurses Association Standards of Practice and the Joint Commission on Accreditation of Hospitals are also addressed as they relate to this data base. The advantages and disadvantages of such an approach to computerized documentation are discussed.
The simulation model of planar electrochemical transducer
Zhevnenko, D. A.; Vergeles, S. S.; Krishtop, T. V.; Tereshonok, D. V.; Gornev, E. S.; Krishtop, V. G.
2016-12-01
Planar electrochemical systems are very perspective to build modern motion and pressure sensors. Planar microelectronic technology is successfully used for electrochemical transducer of motion parameters. These systems are characterized by an exceptionally high sensitivity towards mechanic exposure due to high rate of conversion of the mechanic signal to electric current. In this work, we have developed a mathematical model of this planar electrochemical system, which detects the mechanical signals. We simulate the processes of mass and charge transfer in planar electrochemical transducer and calculated its transfer function with different geometrical parameters of the system.
Agent-based modeling and simulation
Taylor, Simon
2014-01-01
Operational Research (OR) deals with the use of advanced analytical methods to support better decision-making. It is multidisciplinary with strong links to management science, decision science, computer science and many application areas such as engineering, manufacturing, commerce and healthcare. In the study of emergent behaviour in complex adaptive systems, Agent-based Modelling & Simulation (ABMS) is being used in many different domains such as healthcare, energy, evacuation, commerce, manufacturing and defense. This collection of articles presents a convenient introduction to ABMS with pa
Petroleum reservoir data for testing simulation models
Energy Technology Data Exchange (ETDEWEB)
Lloyd, J.M.; Harrison, W.
1980-09-01
This report consists of reservoir pressure and production data for 25 petroleum reservoirs. Included are 5 data sets for single-phase (liquid) reservoirs, 1 data set for a single-phase (liquid) reservoir with pressure maintenance, 13 data sets for two-phase (liquid/gas) reservoirs and 6 for two-phase reservoirs with pressure maintenance. Also given are ancillary data for each reservoir that could be of value in the development and validation of simulation models. A bibliography is included that lists the publications from which the data were obtained.
Schwinger model simulations with dynamical overlap fermions
Bietenholz, W; Volkholz, J
2007-01-01
We present simulation results for the 2-flavour Schwinger model with dynamical overlap fermions. In particular we apply the overlap hypercube operator at seven light fermion masses. In each case we collect sizable statistics in the topological sectors 0 and 1. Since the chiral condensate Sigma vanishes in the chiral limit, we observe densities for the microscopic Dirac spectrum, which have not been addressed yet by Random Matrix Theory (RMT). Nevertheless, by confronting the averages of the lowest eigenvalues in different topological sectors with chiral RMT in unitary ensemble we obtain -- for the very light fermion masses -- values for $\\Sigma$ that follow closely the analytical predictions in the continuum.
Schwinger model simulations with dynamical overlap fermions
Energy Technology Data Exchange (ETDEWEB)
Bietenholz, W. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Shcheredin, S. [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Volkholz, J. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik
2007-11-15
We present simulation results for the 2-flavour Schwinger model with dynamical overlap fermions. In particular we apply the overlap hypercube operator at seven light fermion masses. In each case we collect sizable statistics in the topological sectors 0 and 1. Since the chiral condensate {sigma} vanishes in the chiral limit, we observe densities for the microscopic Dirac spectrum, which have not been addressed yet by Random Matrix Theory (RMT). Nevertheless, by confronting the averages of the lowest eigenvalues in different topological sectors with chiral RMT in unitary ensemble we obtain - for the very light fermion masses - values for {sigma} that follow closely the analytical predictions in the continuum. (orig.)
Induction generator models in dynamic simulation tools
DEFF Research Database (Denmark)
Knudsen, Hans; Akhmatov, Vladislav
1999-01-01
. It is found to be possible to include a transient model in dynamic stability tools and, then, obtain correct results also in dynamic tools. The representation of the rotating system influences on the voltage recovery shape which is an important observation in case of windmills, where a heavy mill is connected......For AC network with large amount of induction generators (windmills) the paper demonstrates a significant discrepancy in the simulated voltage recovery after fault in weak networks when comparing dynamic and transient stability descriptions and the reasons of discrepancies are explained...
CASTOR detector Model, objectives and simulated performance
Angelis, Aris L S; Bartke, Jerzy; Bogolyubsky, M Yu; Chileev, K; Erine, S; Gladysz-Dziadus, E; Kharlov, Yu V; Kurepin, A B; Lobanov, M O; Maevskaya, A I; Mavromanolakis, G; Nicolis, N G; Panagiotou, A D; Sadovsky, S A; Wlodarczyk, Z
2001-01-01
We present a phenomenological model describing the formation and evolution of a Centauro fireball in the baryon-rich region in nucleus-nucleus interactions in the upper atmosphere and at the LHC. The small particle multiplicity and imbalance of electromagnetic and hadronic content characterizing a Centauro event and also the strongly penetrating particles (assumed to be strangelets) frequently accompanying them can be naturally explained. We describe the CASTOR calorimeter, a subdetector of the ALICE experiment dedicated to the search for Centauro in the very forward, baryon-rich region of central Pb+Pb collisions at the LHC. The basic characteristics and simulated performance of the calorimeter are presented. (22 refs).
CASTOR detector. Model, objectives and simulated performance
Energy Technology Data Exchange (ETDEWEB)
Angelis, A. L. S.; Mavromanolakis, G.; Panagiotou, A. D. [University of Athens, Nuclear and Particle Physics Division, Athens (Greece); Aslanoglou, X.; Nicolis, N. [Ioannina Univ., Ioannina (Greece). Dept. of Physics; Bartke, J.; Gladysz-Dziadus, E. [Institute of Nuclear Physics, Cracow (Poland); Lobanov, M.; Erine, S.; Kharlov, Y.V.; Bogolyubsky, M.Y. [Institute for High Energy Physics, Protvino (Russian Federation); Kurepin, A.B.; Chileev, K. [Institute for Nuclear Research, Moscow (Russian Federation); Wlodarczyk, Z. [Pedagogical University, Institute of Physics, Kielce (Poland)
2001-10-01
It is presented a phenomenological model describing the formation and evolution of a Centauro fireball in the baryon-rich region in nucleus-nucleus interactions in the upper atmosphere and at the LHC. The small particle multiplicity and imbalance of electromagnetic and hadronic content characterizing a Centauro event and also the strongly penetrating particles (assumed to be strangelets) frequently accompanying them can be naturally explained. It is described the CASTOR calorimeter, a sub detector of the ALICE experiment dedicated to the search for Centauro in the very forward, baryon-rich region of central Pb+Pb collisions at the LHC. The basic characteristics and simulated performance of the calorimeter are presented.
Modelling and simulations of controlled release fertilizer
Irfan, Sayed Ameenuddin; Razali, Radzuan; Shaari, Ku Zilati Ku; Mansor, Nurlidia
2016-11-01
The recent advancement in controlled release fertilizer has provided an alternative solution to the conventional urea, controlled release fertilizer has a good plant nutrient uptake they are environment friendly. To have an optimum plant intake of nutrients from controlled release fertilizer it is very essential to understand the release characteristics. A mathematical model is developed to predict the release characteristics from polymer coated granule. Numerical simulations are performed by varying the parameters radius of granule, soil water content and soil porosity to study their effect on fertilizer release. Understanding these parameters helps in the better design and improve the efficiency of controlled release fertilizer.
Monte Carlo Simulation of River Meander Modelling
Posner, A. J.; Duan, J. G.
2010-12-01
This study first compares the first order analytical solutions for flow field by Ikeda et. al. (1981) and Johanesson and Parker (1989b). Ikeda et. al.’s (1981) linear bank erosion model was implemented to predict the rate of bank erosion in which the bank erosion coefficient is treated as a stochastic variable that varies with physical properties of the bank (e.g. cohesiveness, stratigraphy, vegetation density). The developed model was used to predict the evolution of meandering planforms. Then, the modeling results were analyzed and compared to the observed data. Since the migration of meandering channel consists of downstream translation, lateral expansion, and downstream or upstream rotations. Several measures are formulated in order to determine which of the resulting planform is closest to the experimental measured one. Results from the deterministic model highly depend on the calibrated erosion coefficient. Since field measurements are always limited, the stochastic model yielded more realistic predictions of meandering planform evolutions. Due to the random nature of bank erosion coefficient, the meandering planform evolution is a stochastic process that can only be accurately predicted by a stochastic model. Quasi-2D Ikeda (1989) flow solution with Monte Carlo Simulation of Bank Erosion Coefficient.
Axisymmetric Vortex Simulations with Various Turbulence Models
Directory of Open Access Journals (Sweden)
Brian Howard Fiedler
2010-10-01
Full Text Available The CFD code FLUENT^{TM} has been applied to a vortex within an updraft above a frictional lower boundary. The sensitivity of vortex intensity and structure to the choice of turbulent model is explored. A high Reynolds number of 10^{8} is employed to make the investigation relevant to the atmospheric vortex known as a tornado. The simulations are axisymmetric and are integrated forward in time to equilibrium. In a variety of turbulence models tested, the Reynolds Stress Model allows for the greatest intensification of the vortex, with the azimuthal wind speed near the surface being 2.4 times the speed of the updraft, consistent with the destructive nature of tornadoes. The Standard k-e Model, which is simpler than the Reynolds Stress Model but still more detailed than what is commonly available in numerical weather prediction models, produces an azimuthal wind speed near the surface of at most 0.6 times the updraft speed.
A COMPUTERIZED OPERATOR SUPPORT SYSTEM PROTOTYPE
Energy Technology Data Exchange (ETDEWEB)
Thomas A. Ulrich; Roger Lew; Ronald L. Boring; Ken Thomas
2015-03-01
A computerized operator support system (COSS) is proposed for use in nuclear power plants to assist control room operators in addressing time-critical plant upsets. A COSS is a collection of technologies to assist operators in monitoring overall plant performance and making timely, informed decisions on appropriate control actions for the projected plant condition. A prototype COSS was developed in order to demonstrate the concept and provide a test bed for further research. The prototype is based on four underlying elements consisting of a digital alarm system, computer-based procedures, piping and instrumentation diagram system representations, and a recommender module for mitigation actions. The initial version of the prototype is now operational at the Idaho National Laboratory using the Human System Simulation Laboratory.
Termination Criteria for Computerized Classification Testing
Directory of Open Access Journals (Sweden)
Nathan A. Thompson
2011-02-01
Full Text Available Computerized classification testing (CCT is an approach to designing tests with intelligent algorithms, similar to adaptive testing, but specifically designed for the purpose of classifying examinees into categories such as - pass- and - fail.- Like adaptive testing for point estimation of ability, the key component is the termination criterion, namely the algorithm that decides whether to classify the examinee and end the test or to continue and administer another item. This paper applies a newly suggested termination criterion, the generalized likelihood ratio (GLR, to CCT. It also explores the role of the indifference region in the specification of likelihood-ratio based termination criteria, comparing the GLR to the sequential probability ratio test. Results from simulation studies suggest that the GLR is always at least as efficient as existing methods.
Simulation model for port shunting yards
Rusca, A.; Popa, M.; Rosca, E.; Rosca, M.; Dragu, V.; Rusca, F.
2016-08-01
Sea ports are important nodes in the supply chain, joining two high capacity transport modes: rail and maritime transport. The huge cargo flows transiting port requires high capacity construction and installation such as berths, large capacity cranes, respectively shunting yards. However, the port shunting yards specificity raises several problems such as: limited access since these are terminus stations for rail network, the in-output of large transit flows of cargo relatively to the scarcity of the departure/arrival of a ship, as well as limited land availability for implementing solutions to serve these flows. It is necessary to identify technological solutions that lead to an answer to these problems. The paper proposed a simulation model developed with ARENA computer simulation software suitable for shunting yards which serve sea ports with access to the rail network. Are investigates the principal aspects of shunting yards and adequate measures to increase their transit capacity. The operation capacity for shunting yards sub-system is assessed taking in consideration the required operating standards and the measure of performance (e.g. waiting time for freight wagons, number of railway line in station, storage area, etc.) of the railway station are computed. The conclusion and results, drawn from simulation, help transports and logistics specialists to test the proposals for improving the port management.
The mathematical model of a LUNG simulator
Directory of Open Access Journals (Sweden)
František Šolc
2014-12-01
Full Text Available The paper discusses the design, modelling, implementation and testing of a specific LUNG simulator,. The described research was performed as a part of the project AlveoPic – Advanced Lung Research for Veterinary Medicine of Particles for Inhalation. The simulator was designed to establish a combined study programme comprising Biomedical Engineering Sciences (FEEC BUT and Healthcare and Rehabilitation Technology (FH Technikum Wien. The simulator is supposed to be an advanced laboratory equipment which should enhance the standard of the existing research activities within the above-mentioned study programs to the required level. Thus, the proposed paper introduces significant technical equipment for the laboratory education of students at both FH Technikum Wien and the Faculty of Electrical Engineering and Communication, Brno University of Technology. The apparatuses described here will be also used to support cooperative research activities. In the given context, the authors specify certain technical solutions and parameters related to artificial lungs, present the electrical equipment of the system, and point out the results of the PC-based measurement and control.
Three-dimensional conceptual model for service-oriented simulation
Institute of Scientific and Technical Information of China (English)
Wen-guang WANG; Wei-ping WANG; Justyna ZANDER; Yi-fan ZHU
2009-01-01
In this letter, we propose a novel three-dimensional conceptual model for an emerging service-oriented simulation paradigm. The model can be used as a guideline or an analytic means to find the potential and possible future directions of the current simulation frameworks, In particular, the model inspects the crossover between the disciplines of modeling and simulation,service-orientation, and software/systems engineering. Finally, two specific simulation frameworks are studied as examples.
Three-dimensional conceptual model for service-oriented simulation
Wang, Wenguang; Zander, Justyna; Zhu, Yifan; 10.1631/jzus.A0920258
2009-01-01
In this letter, we propose a novel three-dimensional conceptual model for an emerging service-oriented simulation paradigm. The model can be used as a guideline or an analytic means to find the potential and possible future directions of the current simulation frameworks. In particular, the model inspects the crossover between the disciplines of modeling and simulation, service-orientation, and software/systems engineering. Finally, two specific simulation frameworks are studied as examples.
Computerized tomography. Yesterday and today
Energy Technology Data Exchange (ETDEWEB)
Ethier, R.; Melanson, D. (Montreal Neurological Inst., Quebec (Canada))
1983-10-01
This presentation describes the evolution of computerized tomography over the past decade and its contribution to the radiologic investigation of neurologic disorders. This new technique has not only stimulated development in the diagnosis of cerebral diseases, but the whole body as well. Detailed investigation of the spine, spinal cord, sella turcica, the orbits, as well as the petrous pyramids has been made possible through the development of high resolution scanning.
Global Solar Dynamo Models: Simulations and Predictions
Indian Academy of Sciences (India)
Mausumi Dikpati; Peter A. Gilman
2008-03-01
Flux-transport type solar dynamos have achieved considerable success in correctly simulating many solar cycle features, and are now being used for prediction of solar cycle timing and amplitude.We first define flux-transport dynamos and demonstrate how they work. The essential added ingredient in this class of models is meridional circulation, which governs the dynamo period and also plays a crucial role in determining the Sun’s memory about its past magnetic fields.We show that flux-transport dynamo models can explain many key features of solar cycles. Then we show that a predictive tool can be built from this class of dynamo that can be used to predict mean solar cycle features by assimilating magnetic field data from previous cycles.
Design and Simulation of Toroidal Twister Model
Institute of Scientific and Technical Information of China (English)
TIAN Huifang; LIN Xizhen; ZENG Qinqin
2006-01-01
Toroidal composite vessel winded with fiber is a new kind of structural pressure vessels, which not only has high structure efficiency of compound materials pressure vessel, good security and so on, but also has special shape and the property of utilizing toroidal space, and the prospect of the application of toroidal composite vessel winded with fiber is extremely broad. By introducing parameters establishment of toroidal vessel and elaborating the principle of filament winding for toroidal vessel, the design model of filament winding machine for toroidal vessel has been introduced, and the design model has been dynamically simulated by the software of ADAMS, which will give more referrence for the design of real toroidal vessel twister.
VISION: Verifiable Fuel Cycle Simulation Model
Energy Technology Data Exchange (ETDEWEB)
Jacob J. Jacobson; Abdellatif M. Yacout; Gretchen E. Matthern; Steven J. Piet; David E. Shropshire
2009-04-01
The nuclear fuel cycle is a very complex system that includes considerable dynamic complexity as well as detail complexity. In the nuclear power realm, there are experts and considerable research and development in nuclear fuel development, separations technology, reactor physics and waste management. What is lacking is an overall understanding of the entire nuclear fuel cycle and how the deployment of new fuel cycle technologies affects the overall performance of the fuel cycle. The Advanced Fuel Cycle Initiative’s systems analysis group is developing a dynamic simulation model, VISION, to capture the relationships, timing and delays in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works and can transition as technologies are changed. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model and some examples of how to use VISION.
Modeling and visual simulation of Microalgae photobioreactor
Zhao, Ming; Hou, Dapeng; Hu, Dawei
Microalgae is a kind of nutritious and high photosynthetic efficiency autotrophic plant, which is widely distributed in the land and the sea. It can be extensively used in medicine, food, aerospace, biotechnology, environmental protection and other fields. Photobioreactor which is important equipment is mainly used to cultivate massive and high-density microalgae. In this paper, based on the mathematical model of microalgae which grew under different light intensity, three-dimensional visualization model was built and implemented in 3ds max, Virtools and some other three dimensional software. Microalgae is photosynthetic organism, it can efficiently produce oxygen and absorb carbon dioxide. The goal of the visual simulation is to display its change and impacting on oxygen and carbon dioxide intuitively. In this paper, different temperatures and light intensities were selected to control the photobioreactor, and dynamic change of microalgal biomass, Oxygen and carbon dioxide was observed with the aim of providing visualization support for microalgal and photobioreactor research.
A rainfall simulation model for agricultural development in Bangladesh
Directory of Open Access Journals (Sweden)
M. Sayedur Rahman
2000-01-01
Full Text Available A rainfall simulation model based on a first-order Markov chain has been developed to simulate the annual variation in rainfall amount that is observed in Bangladesh. The model has been tested in the Barind Tract of Bangladesh. Few significant differences were found between the actual and simulated seasonal, annual and average monthly. The distribution of number of success is asymptotic normal distribution. When actual and simulated daily rainfall data were used to drive a crop simulation model, there was no significant difference of rice yield response. The results suggest that the rainfall simulation model perform adequately for many applications.
Toy Models for Galaxy Formation versus Simulations
Dekel, A; Tweed, D; Cacciato, M; Ceverino, D; Primack, J R
2013-01-01
We describe simple useful toy models for key processes of galaxy formation in its most active phase, at z > 1, and test the approximate expressions against the typical behaviour in a suite of high-resolution hydro-cosmological simulations of massive galaxies at z = 4-1. We address in particular the evolution of (a) the total mass inflow rate from the cosmic web into galactic haloes based on the EPS approximation, (b) the penetration of baryonic streams into the inner galaxy, (c) the disc size, (d) the implied steady-state gas content and star-formation rate (SFR) in the galaxy subject to mass conservation and a universal star-formation law, (e) the inflow rate within the disc to a central bulge and black hole as derived using energy conservation and self-regulated Q ~ 1 violent disc instability (VDI), and (f) the implied steady state in the disc and bulge. The toy models provide useful approximations for the behaviour of the simulated galaxies. We find that (a) the inflow rate is proportional to mass and to (...
Modelling and simulation of multitechnological machine systems
Energy Technology Data Exchange (ETDEWEB)
Holopainen, T. (ed.) [VTT Manufacturing Technology, Espoo (Finland)
2001-07-01
The Smart Machines and Systems 2010 (SMART) technology programme 1997-2000 aimed at supporting the machine and electromechanical industries in incorporating the modern technology into their products and processes. The public research projects in this programme were planned to accumulate the latest research results and transfer them for the benefit of industrial product development. The major research topic in the SMART programme was called Modelling and Simulation of Multitechnological Mechatronic Systems. The behaviour of modern machine systems and subsystems addresses many different types of physical phenomena and their mutual interactions: mechanical behaviour of structures, electromagnetic effects, hydraulics, vibrations and acoustics etc. together with associated control systems and software. The actual research was carried out in three separate projects called Modelling and Simulation of Mechtronic Machine Systems for Product Development and Condition Monitoring Purposes (MASI), Virtual Testing of Hydraulically Driven Machines (HYSI), and Control of Low Frequency Vibration of a Mobile Machine (AKSUS). This publication contains the papers presented at the final seminar of these three research projects, held on November 30th at Otaniemi Espoo. (orig.)
Multidimensional Computerized Adaptive Testing for Indonesia Junior High School Biology
Kuo, Bor-Chen; Daud, Muslem; Yang, Chih-Wei
2015-01-01
This paper describes a curriculum-based multidimensional computerized adaptive test that was developed for Indonesia junior high school Biology. In adherence to the Indonesian curriculum of different Biology dimensions, 300 items was constructed, and then tested to 2238 students. A multidimensional random coefficients multinomial logit model was…
Multidimensional Computerized Adaptive Testing for Indonesia Junior High School Biology
Kuo, Bor-Chen; Daud, Muslem; Yang, Chih-Wei
2015-01-01
This paper describes a curriculum-based multidimensional computerized adaptive test that was developed for Indonesia junior high school Biology. In adherence to the Indonesian curriculum of different Biology dimensions, 300 items was constructed, and then tested to 2238 students. A multidimensional random coefficients multinomial logit model was…
Computerized Mastery Testing Using Fuzzy Set Decision Theory.
Du, Yi; And Others
1993-01-01
A new computerized mastery test is described that builds on the Lewis and Sheehan procedure (sequential testlets) (1990), but uses fuzzy set decision theory to determine stopping rules and the Rasch model to calibrate items and estimate abilities. Differences between fuzzy set and Bayesian methods are illustrated through an example. (SLD)
Towards Modelling and Simulation of Crowded Environments in Cell Biology
Bittig, Arne T.; Jeschke, Matthias; Uhrmacher, Adelinde M.
2010-09-01
In modelling and simulation of cell biological processes, spatial homogeneity in the distribution of components is a common but not always valid assumption. Spatial simulation methods differ in computational effort and accuracy, and usually rely on tool-specific input formats for model specification. A clear separation between modelling and simulation allows a declarative model specification thereby facilitating reuse of models and exploiting different simulators. We outline a modelling formalism covering both stochastic spatial simulation at the population level and simulation of individual entities moving in continuous space as well as the combination thereof. A multi-level spatial simulator is presented that combines populations of small particles simulated according to the Next Subvolume Method with individually represented large particles following Brownian motion. This approach entails several challenges that need to be overcome, but nicely balances between calculation effort and required levels of detail.
Modeling and simulation of cascading contingencies
Zhang, Jianfeng
This dissertation proposes a new approach to model and study cascading contingencies in large power systems. The most important contribution of the work involves the development and validation of a heuristic analytic model to assess the likelihood of cascading contingencies, and the development and validation of a uniform search strategy. We model the probability of cascading contingencies as a function of power flow and power flow changes. Utilizing logistic regression, the proposed model is calibrated using real industry data. This dissertation analyzes random search strategies for Monte Carlo simulations and proposes a new uniform search strategy based on the Metropolis-Hastings Algorithm. The proposed search strategy is capable of selecting the most significant cascading contingencies, and it is capable of constructing an unbiased estimator to provide a measure of system security. This dissertation makes it possible to reasonably quantify system security and justify security operations when economic concerns conflict with reliability concerns in the new competitive power market environment. It can also provide guidance to system operators about actions that may be taken to reduce the risk of major system blackouts. Various applications can be developed to take advantage of the quantitative security measures provided in this dissertation.
[Computerizing the radiological sign].
Bertaud, V; Belhadj, I; Dameron, O; Garcelon, N; Hendaoui, L; Marin, F; Duvauferrier, R
2007-01-01
The goal of this article is to present to the radiologist the different theories of the sign and their consequences for sign representation in computer systems. All the theories of the sign are presented, but the most relevant are highlighted in order to explain the great modeling systems currently in use (such as DICOM-SR or the UMLS). The constructivist approach of the notion of disease, the semiosis process, which starting from signs produces new signs, and the structuralist analysis of sign through language are emphasized. The purpose of this analysis is to end up with a consensual representation of the sign that can be understood by human beings and processed by machines. Such a representation, also known as an ontology, is based on a semantic organization of language, thus allowing medicine to become a truly scientific discipline. It aims at disambiguating the symbols given to machines, which will help us in our reasoning.
Nonlinear distortion in wireless systems modeling and simulation with Matlab
Gharaibeh, Khaled M
2011-01-01
This book covers the principles of modeling and simulation of nonlinear distortion in wireless communication systems with MATLAB simulations and techniques In this book, the author describes the principles of modeling and simulation of nonlinear distortion in single and multichannel wireless communication systems using both deterministic and stochastic signals. Models and simulation methods of nonlinear amplifiers explain in detail how to analyze and evaluate the performance of data communication links under nonlinear amplification. The book addresses the analysis of nonlinear systems
AISIM (Automated Interactive Simulation Modeling System) VAX Version Training Manual.
1985-02-01
AD-Ri6t 436 AISIM (RUTOMATED INTERACTIVE SIMULATION MODELING 1/2 SYSTEM) VAX VERSION TRAI (U) HUGHES AIRCRAFT CO FULLERTON CA GROUND SYSTEMS GROUP S...Continue on reverse if necessary and Identify by block number) THIS DOCUMENT IS THE TRAINING MANUAL FOR THE AUTOMATED INTERACTIVE SIMULATION MODELING SYSTEM...form. Page 85 . . . . . . . . APPENDIX B SIMULATION REPORT FOR WORKING EXAMPLE Pa jPage.8 7AD-Ai6i 46 ISIM (AUTOMATED INTERACTIVE SIMULATION MODELING 2
Tecnomatix Plant Simulation modeling and programming by means of examples
Bangsow, Steffen
2015-01-01
This book systematically introduces the development of simulation models as well as the implementation and evaluation of simulation experiments with Tecnomatix Plant Simulation. It deals with all users of Plant Simulation, who have more complex tasks to handle. It also looks for an easy entry into the program. Particular attention has been paid to introduce the simulation flow language SimTalk and its use in various areas of the simulation. The author demonstrates with over 200 examples how to combine the blocks for simulation models and how to deal with SimTalk for complex control and analys
Modeling human response errors in synthetic flight simulator domain
Ntuen, Celestine A.
1992-01-01
This paper presents a control theoretic approach to modeling human response errors (HRE) in the flight simulation domain. The human pilot is modeled as a supervisor of a highly automated system. The synthesis uses the theory of optimal control pilot modeling for integrating the pilot's observation error and the error due to the simulation model (experimental error). Methods for solving the HRE problem are suggested. Experimental verification of the models will be tested in a flight quality handling simulation.
Cognitive Modeling for Agent-Based Simulation of Child Maltreatment
Hu, Xiaolin; Puddy, Richard
This paper extends previous work to develop cognitive modeling for agent-based simulation of child maltreatment (CM). The developed model is inspired from parental efficacy, parenting stress, and the theory of planned behavior. It provides an explanatory, process-oriented model of CM and incorporates causality relationship and feedback loops from different factors in the social ecology in order for simulating the dynamics of CM. We describe the model and present simulation results to demonstrate the features of this model.
LADEE Satellite Modeling and Simulation Development
Adams, Michael; Cannon, Howard; Frost, Chad
2011-01-01
As human activity on and around the Moon increases, so does the likelihood that our actions will have an impact on its atmosphere. The Lunar Atmosphere and Dust Environment Explorer (LADEE), a NASA satellite scheduled to launch in 2013, will orbit the Moon collecting composition, density, and time variability data to characterize the current state of the lunar atmosphere. LADEE will also test the concept of the "Modular Common Bus" spacecraft architecture, an effort to reduce both development time and cost by designing reusable, modular components for use in multiple missions with similar requirements. An important aspect of this design strategy is to both simulate the spacecraft and develop the flight code in Simulink, a block diagram-style programming language that allows easy algorithm visualization and performance testing. Before flight code can be tested, however, a realistic simulation of the satellite and its dynamics must be generated and validated. This includes all of the satellite control system components such as actuators used for force and torque generation and sensors used for inertial orientation reference. My primary responsibilities have included designing, integrating, and testing models for the LADEE thrusters, reaction wheels, star trackers, and rate gyroscopes.
Modeling and simulation of axisymmetric stagnation flames
Sone, Kazuo
Laminar flame modeling is an important element in turbulent combustion research. The accuracy of a turbulent combustion model is highly dependent upon our understanding of laminar flames and their behavior in many situations. How much we understand combustion can only be measured by how well the model describes and predicts combustion phenomena. One of the most commonly used methane combustion models is GRI-Mech 3.0. However, how well the model describes the reacting flow phenomena is still uncertain even after many attempts to validate the model or quantify uncertainties. In the present study, the behavior of laminar flames under different aerodynamic and thermodynamic conditions is studied numerically in a stagnation-flow configuration. In order to make such a numerical study possible, the spectral element method is reformulated to accommodate the large density variations in methane reacting flows. In addition, a new axisymmetric basis function set for the spectral element method that satisfies the correct behavior near the axis is developed, and efficient integration techniques are developed to accurately model axisymmetric reacting flow within a reasonable amount of computational time. The numerical method is implemented using an object-oriented programming technique, and the resulting computer program is verified with several different verification methods. The present study then shows variances with the commonly used GRI-Mech 3.0 chemical kinetics model through a direct simulation of laboratory flames that allows direct comparison to experimental data. It is shown that the methane combustion model based on GRI-Mech 3.0 works well for methane-air mixtures near stoichiometry. However, GRI-Mech 3.0 leads to an overprediction of laminar flame speed for lean mixtures and an underprediction for rich mixtures. This result is slightly different from conclusion drawn in previous work, in which experimental data are compared with a one-dimensional numerical solutions
Modeling and simulation technology readiness levels.
Energy Technology Data Exchange (ETDEWEB)
Clay, Robert L.; Shneider, Max S.; Marburger, S. J.; Trucano, Timothy Guy
2006-01-01
This report summarizes the results of an effort to establish a framework for assigning and communicating technology readiness levels (TRLs) for the modeling and simulation (ModSim) capabilities at Sandia National Laboratories. This effort was undertaken as a special assignment for the Weapon Simulation and Computing (WSC) program office led by Art Hale, and lasted from January to September 2006. This report summarizes the results, conclusions, and recommendations, and is intended to help guide the program office in their decisions about the future direction of this work. The work was broken out into several distinct phases, starting with establishing the scope and definition of the assignment. These are characterized in a set of key assertions provided in the body of this report. Fundamentally, the assignment involved establishing an intellectual framework for TRL assignments to Sandia's modeling and simulation capabilities, including the development and testing of a process to conduct the assignments. To that end, we proposed a methodology for both assigning and understanding the TRLs, and outlined some of the restrictions that need to be placed on this process and the expected use of the result. One of the first assumptions we overturned was the notion of a ''static'' TRL--rather we concluded that problem context was essential in any TRL assignment, and that leads to dynamic results (i.e., a ModSim tool's readiness level depends on how it is used, and by whom). While we leveraged the classic TRL results from NASA, DoD, and Sandia's NW program, we came up with a substantially revised version of the TRL definitions, maintaining consistency with the classic level definitions and the Predictive Capability Maturity Model (PCMM) approach. In fact, we substantially leveraged the foundation the PCMM team provided, and augmented that as needed. Given the modeling and simulation TRL definitions and our proposed assignment methodology, we
Modeling and simulation of surface roughness
Energy Technology Data Exchange (ETDEWEB)
Patrikar, Rajendra M
2004-04-30
With the technology advancement, electronic devices are miniaturized at every development node. Physical parameters such as microscopic roughness are affecting these devices because surface to volume ratio is increasing rapidly. On all the real surfaces microscopic roughness appears, which affects many electronic properties of the material, which in turn decides the yield and reliability of the devices. Different type of parameters and simulation methods are used to describe the surface roughness. Classically surface roughness was modeled by methods such as power series and Fast Fourier Transform (FFT). Limitations of this methods lead to use the concept of self-similar fractals to model the rough surface through Mandelbrot-Weierstrass function. It is difficult to express surface roughness as a function of process parameters in the form of analytical functions. Method based on neural networks has been used to model these surfaces to map the process parameters to roughness parameters. Finally, change in electrical parameters such as capacitance, resistance and noise due to surface roughness has been computed by numerical methods.
Aminoglycoside nephrotoxicity: modeling, simulation, and control.
Rougier, Florent; Claude, Daniel; Maurin, Michel; Sedoglavic, Alexandre; Ducher, Michel; Corvaisier, Stéphane; Jelliffe, Roger; Maire, Pascal
2003-03-01
The main constraints on the administration of aminoglycosides are the risks of nephrotoxicity and ototoxicity, which can lead to acute, renal, vestibular, and auditory toxicities. In the present study we focused on nephrotoxicity. No reliable predictor of nephrotoxicity has been found to date. We have developed a deterministic model which describes the pharmacokinetic behavior of aminoglycosides (with a two-compartment model), the kinetics of aminoglycoside accumulation in the renal cortex, the effects of aminoglycosides on renal cells, the resulting effects on renal function by tubuloglomerular feedback, and the resulting effects on serum creatinine concentrations. The pharmacokinetic parameter values were estimated by use of the NPEM program. The estimated pharmacodynamic parameter values were obtained after minimization of the least-squares objective function between the measured and the calculated serum creatinine concentrations. A simulation program assessed the influences of the dosage regimens on the occurrence of nephrotoxicity. We have also demonstrated the relevancy of modeling of the circadian rhythm of the renal function. We have shown the ability of the model to fit with 49 observed serum creatinine concentrations for a group of eight patients treated for endocarditis by comparison with 49 calculated serum creatinine concentrations (r(2) = 0.988; P < 0.001). We have found that for the same daily dose, the nephrotoxicity observed with a thrice-daily administration schedule appears more rapidly, induces a greater decrease in renal function, and is more prolonged than those that occur with less frequent administration schedules (for example, once-daily administration). Moreover, for once-daily administration, we have demonstrated that the time of day of administration can influence the incidence of aminoglycoside nephrotoxicity. The lowest level of nephrotoxicity was observed when aminoglycosides were administered at 1:30 p.m. Clinical application of this
Kong, Jian; Yao, Yibin; Liu, Lei; Zhai, Changzhi; Wang, Zemin
2016-08-01
A new algorithm for ionosphere tomography using the mapping function is proposed in this paper. First, the new solution splits the integration process into four layers along the observation ray, and then, the single-layer model (SLM) is applied to each integration part using a mapping function. Next, the model parameters are estimated layer by layer with the Kalman filtering method by introducing the scale factor (SF) γ to solve the ill-posed problem. Finally, the inversed images of different layers are combined into the final CIT image. We utilized simulated data from 23 IGS GPS stations around Europe to verify the estimation accuracy of the new algorithm; the results show that the new CIT model has better accuracy than the SLM in dense data areas and the CIT residuals are more closely grouped. The stability of the new algorithm is discussed by analyzing model accuracy under different error levels (the max errors are 5TECU, 10TECU, 15TECU, respectively). In addition, the key preset parameter, SFγ , which is given by the International Reference Ionosphere model (IRI2012). The experiment is designed to test the sensitivity of the new algorithm to SF variations. The results show that the IRI2012 is capable of providing initial SF values. Also in this paper, the seismic-ionosphere disturbance (SID) of the 2011 Japan earthquake is studied using the new CIT algorithm. Combined with the TEC time sequence of Sat.15, we find that the SID occurrence time and reaction area are highly related to the main shock time and epicenter. According to CIT images, there is a clear vertical electron density upward movement (from the 150-km layer to the 450-km layer) during this SID event; however, the peak value areas in the different layers were different, which means that the horizontal movement velocity is not consistent among the layers. The potential physical triggering mechanism is also discussed in this paper. Compared with the SLM, the RMS of the new CIT model is improved by
The modeling of miniature UAV flight visualization simulation platform
Li, Dong-hui; Li, Xin; Yang, Le-le; Li, Xiong
2015-12-01
This paper combines virtual technology with visualization visual simulation theory, construct the framework of visual simulation platform, apply open source software FlightGear simulator combined with GoogleEarth design a small UAV flight visual simulation platform. Using software AC3D to build 3D models of aircraft and complete the model loading based on XML configuration, the design and simulation of visualization modeling visual platform is presented. By using model-driven and data transforming in FlightGear , the design of data transmission module is realized based on Visual Studio 2010 development platform. Finally combined with GoogleEarth it can achieve the tracking and display.
Shuttle operations simulation model programmers'/users' manual
Porter, D. G.
1972-01-01
The prospective user of the shuttle operations simulation (SOS) model is given sufficient information to enable him to perform simulation studies of the space shuttle launch-to-launch operations cycle. The procedures used for modifying the SOS model to meet user requirements are described. The various control card sequences required to execute the SOS model are given. The report is written for users with varying computer simulation experience. A description of the components of the SOS model is included that presents both an explanation of the logic involved in the simulation of the shuttle operations cycle and a description of the routines used to support the actual simulation.
Discrete Element Simulation of Asphalt Mastics Based on Burgers Model
Institute of Scientific and Technical Information of China (English)
LIU Yu; FENG Shi-rong; HU Xia-guang
2007-01-01
In order to investigate the viscoelastic performance of asphalt mastics, a micro-mechanical model for asphalt mastics was built by applying Burgers model to discrete element simulation and constructing Burgers contact model. Then the numerical simulation of creep tests was conducted, and results from the simulation were compared with the analytical solution for Burgers model. The comparision snowed that the two results agreed well with each other, suggesting that discrete element model based on Burgers model could be employed in the numerical simulation for asphalt mastics.
A Geostationary Earth Orbit Satellite Model Using Easy Java Simulation
Wee, Loo Kang; Goh, Giam Hwee
2013-01-01
We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modelled using a Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using a simple constant angular velocity equation. We discuss four computer model design ideas: (1) a simple and realistic…
Knowledge-based modeling of discrete-event simulation systems
H. de Swaan Arons
1999-01-01
textabstractModeling a simulation system requires a great deal of customization. At first sight no system seems to resemble exactly another system and every time a new model has to be designed the modeler has to start from scratch. The present simulation languages provide the modeler with powerful
Knowledge-based modeling of discrete-event simulation systems
H. de Swaan Arons
1999-01-01
textabstractModeling a simulation system requires a great deal of customization. At first sight no system seems to resemble exactly another system and every time a new model has to be designed the modeler has to start from scratch. The present simulation languages provide the modeler with powerful t
A Geostationary Earth Orbit Satellite Model Using Easy Java Simulation
Wee, Loo Kang; Goh, Giam Hwee
2013-01-01
We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modelled using a Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using a simple constant angular velocity equation. We discuss four computer model design ideas: (1) a simple and realistic…
Gustafsson, Leif; Sternad, Mikael
2007-10-01
Population models concern collections of discrete entities such as atoms, cells, humans, animals, etc., where the focus is on the number of entities in a population. Because of the complexity of such models, simulation is usually needed to reproduce their complete dynamic and stochastic behaviour. Two main types of simulation models are used for different purposes, namely micro-simulation models, where each individual is described with its particular attributes and behaviour, and macro-simulation models based on stochastic differential equations, where the population is described in aggregated terms by the number of individuals in different states. Consistency between micro- and macro-models is a crucial but often neglected aspect. This paper demonstrates how the Poisson Simulation technique can be used to produce a population macro-model consistent with the corresponding micro-model. This is accomplished by defining Poisson Simulation in strictly mathematical terms as a series of Poisson processes that generate sequences of Poisson distributions with dynamically varying parameters. The method can be applied to any population model. It provides the unique stochastic and dynamic macro-model consistent with a correct micro-model. The paper also presents a general macro form for stochastic and dynamic population models. In an appendix Poisson Simulation is compared with Markov Simulation showing a number of advantages. Especially aggregation into state variables and aggregation of many events per time-step makes Poisson Simulation orders of magnitude faster than Markov Simulation. Furthermore, you can build and execute much larger and more complicated models with Poisson Simulation than is possible with the Markov approach.
A computerized track detector reader
Energy Technology Data Exchange (ETDEWEB)
Rosinski, S.W. (Centralne Lab. Ochrony Radiologicznej, Warsaw (Poland))
1993-01-01
The structure and basic operation function of a computerized facility named Track Detection Reader is described. This facility is used for recording, counting and evaluation of defects made by [alpha]-particles in a solid state detector. It consists of a microscope equipped with the movable stage, a TV screen and PC-AT computer. The microscope stage is being controlled by a stepper motor. The TV screen enables surface visualization of the detector analyzed while the PC-AT computer is being used for digital analysis of the detector surface, according to the functions of the program. (author). 4 refs, 3 figs.
Modeling and Simulation at Tidewater Community College
Summers, Michael
2008-01-01
Investment of $1.5 million in medical simulation technology. Integration of medical simulation activities into the curriculum. Support from TCC leadership. Individual and team activities. Skill development and critical thinking/problem solving skills.
Model simulations of rainfall over southern Africa and its eastern ...
African Journals Online (AJOL)
2016-01-01
Jan 1, 2016 ... 2015). Two different types of CCAM simulations are ana- lysed here. Firstly, an ...... Sweden: observation versus model simulation. Tellus A 63 http:// ... for Atmospheric Sciences, September 2011, Hartebeeshoek. NESBITT SW ...
Lattice Boltzmann modeling of directional wetting: Comparing simulations to experiments
Jansen, H.P.; Sotthewes, K.; Swigchem, van J.; Zandvliet, H.J.W.; Kooij, E.S.
2013-01-01
Lattice Boltzmann Modeling (LBM) simulations were performed on the dynamic behavior of liquid droplets on chemically striped patterned surfaces, ultimately with the aim to develop a predictive tool enabling reliable design of future experiments. The simulations accurately mimic experimental results,
An educational model for ensemble streamflow simulation and uncertainty analysis
National Research Council Canada - National Science Library
AghaKouchak, A; Nakhjiri, N; Habib, E
2013-01-01
...) are interconnected. The educational toolbox includes a MATLAB Graphical User Interface (GUI) and an ensemble simulation scheme that can be used for teaching uncertainty analysis, parameter estimation, ensemble simulation and model sensitivity...
Simulation and Modeling Application in Agricultural Mechanization
Directory of Open Access Journals (Sweden)
R. M. Hudzari
2012-01-01
Full Text Available This experiment was conducted to determine the equations relating the Hue digital values of the fruits surface of the oil palm with maturity stage of the fruit in plantation. The FFB images were zoomed and captured using Nikon digital camera, and the calculation of Hue was determined using the highest frequency of the value for R, G, and B color components from histogram analysis software. New procedure in monitoring the image pixel value for oil palm fruit color surface in real-time growth maturity was developed. The estimation of day harvesting prediction was calculated based on developed model of relationships for Hue values with mesocarp oil content. The simulation model is regressed and predicts the day of harvesting or a number of days before harvest of FFB. The result from experimenting on mesocarp oil content can be used for real-time oil content determination of MPOB color meter. The graph to determine the day of harvesting the FFB was presented in this research. The oil was found to start developing in mesocarp fruit at 65 days before fruit at ripe maturity stage of 75% oil to dry mesocarp.
Modelling toolkit for simulation of maglev devices
Peña-Roche, J.; Badía-Majós, A.
2017-01-01
A stand-alone App1 has been developed, focused on obtaining information about relevant engineering properties of magnetic levitation systems. Our modelling toolkit provides real time simulations of 2D magneto-mechanical quantities for superconductor (SC)/permanent magnet structures. The source code is open and may be customised for a variety of configurations. Ultimately, it relies on the variational statement of the critical state model for the superconducting component and has been verified against experimental data for YBaCuO/NdFeB assemblies. On a quantitative basis, the values of the arising forces, induced superconducting currents, as well as a plot of the magnetic field lines are displayed upon selection of an arbitrary trajectory of the magnet in the vicinity of the SC. The stability issues related to the cooling process, as well as the maximum attainable forces for a given material and geometry are immediately observed. Due to the complexity of the problem, a strategy based on cluster computing, database compression, and real-time post-processing on the device has been implemented.
Simulation Models for Socioeconomic Inequalities in Health: A Systematic Review
Directory of Open Access Journals (Sweden)
Niko Speybroeck
2013-11-01
Full Text Available Background: The emergence and evolution of socioeconomic inequalities in health involves multiple factors interacting with each other at different levels. Simulation models are suitable for studying such complex and dynamic systems and have the ability to test the impact of policy interventions in silico. Objective: To explore how simulation models were used in the field of socioeconomic inequalities in health. Methods: An electronic search of studies assessing socioeconomic inequalities in health using a simulation model was conducted. Characteristics of the simulation models were extracted and distinct simulation approaches were identified. As an illustration, a simple agent-based model of the emergence of socioeconomic differences in alcohol abuse was developed. Results: We found 61 studies published between 1989 and 2013. Ten different simulation approaches were identified. The agent-based model illustration showed that multilevel, reciprocal and indirect effects of social determinants on health can be modeled flexibly. Discussion and Conclusions: Based on the review, we discuss the utility of using simulation models for studying health inequalities, and refer to good modeling practices for developing such models. The review and the simulation model example suggest that the use of simulation models may enhance the understanding and debate about existing and new socioeconomic inequalities of health frameworks.
Powertrain modeling and simulation for off-road vehicles
Energy Technology Data Exchange (ETDEWEB)
Ouellette, S. [McGill Univ., Montreal, PQ (Canada)
2010-07-01
Standard forward facing automotive powertrain modeling and simulation methodology did not perform equally for all vehicles in all applications in the 2010 winter Olympics, 2009 world alpine ski championships, summit station in Greenland, the McGill Formula Hybrid, Unicell QuickSider, and lunar mobility. This presentation provided a standard automotive powertrain modeling and simulation flow chart as well as an example. It also provided a flow chart for location based powertrain modeling and simulation and discussed location based powertrain modeling and simulation implementation. It was found that in certain applications, vehicle-environment interactions cannot be neglected in order to have good model fidelity. Powertrain modeling and simulation of off-road vehicles demands a new approach to powertrain modeling and simulation. It was concluded that the proposed location based methodology could improve the results for off-road vehicles. tabs., figs.
A Simulation Model for Evaluating Distributed Systems Dependability
Dobre, Ciprian; Cristea, Valentin
2012-01-01
In this paper we present a new simulation model designed to evaluate the dependability in distributed systems. This model extends the MONARC simulation model with new capabilities for capturing reliability, safety, availability, security, and maintainability requirements. The model has been implemented as an extension of the multithreaded, process oriented simulator MONARC, which allows the realistic simulation of a wide-range of distributed system technologies, with respect to their specific components and characteristics. The extended simulation model includes the necessary components to inject various failure events, and provides the mechanisms to evaluate different strategies for replication, redundancy procedures, and security enforcement mechanisms, as well. The results obtained in simulation experiments presented in this paper probe that the use of discrete-event simulators, such as MONARC, in the design and development of distributed systems is appealing due to their efficiency and scalability.
Sunspot Modeling: From Simplified Models to Radiative MHD Simulations
Directory of Open Access Journals (Sweden)
Rolf Schlichenmaier
2011-09-01
Full Text Available We review our current understanding of sunspots from the scales of their fine structure to their large scale (global structure including the processes of their formation and decay. Recently, sunspot models have undergone a dramatic change. In the past, several aspects of sunspot structure have been addressed by static MHD models with parametrized energy transport. Models of sunspot fine structure have been relying heavily on strong assumptions about flow and field geometry (e.g., flux-tubes, "gaps", convective rolls, which were motivated in part by the observed filamentary structure of penumbrae or the necessity of explaining the substantial energy transport required to maintain the penumbral brightness. However, none of these models could self-consistently explain all aspects of penumbral structure (energy transport, filamentation, Evershed flow. In recent years, 3D radiative MHD simulations have been advanced dramatically to the point at which models of complete sunspots with sufficient resolution to capture sunspot fine structure are feasible. Here overturning convection is the central element responsible for energy transport, filamentation leading to fine-structure and the driving of strong outflows. On the larger scale these models are also in the progress of addressing the subsurface structure of sunspots as well as sunspot formation. With this shift in modeling capabilities and the recent advances in high resolution observations, the future research will be guided by comparing observation and theory.
Predictive Capability Maturity Model for computational modeling and simulation.
Energy Technology Data Exchange (ETDEWEB)
Oberkampf, William Louis; Trucano, Timothy Guy; Pilch, Martin M.
2007-10-01
The Predictive Capability Maturity Model (PCMM) is a new model that can be used to assess the level of maturity of computational modeling and simulation (M&S) efforts. The development of the model is based on both the authors experience and their analysis of similar investigations in the past. The perspective taken in this report is one of judging the usefulness of a predictive capability that relies on the numerical solution to partial differential equations to better inform and improve decision making. The review of past investigations, such as the Software Engineering Institute's Capability Maturity Model Integration and the National Aeronautics and Space Administration and Department of Defense Technology Readiness Levels, indicates that a more restricted, more interpretable method is needed to assess the maturity of an M&S effort. The PCMM addresses six contributing elements to M&S: (1) representation and geometric fidelity, (2) physics and material model fidelity, (3) code verification, (4) solution verification, (5) model validation, and (6) uncertainty quantification and sensitivity analysis. For each of these elements, attributes are identified that characterize four increasing levels of maturity. Importantly, the PCMM is a structured method for assessing the maturity of an M&S effort that is directed toward an engineering application of interest. The PCMM does not assess whether the M&S effort, the accuracy of the predictions, or the performance of the engineering system satisfies or does not satisfy specified application requirements.
Simulation modeling for long duration spacecraft control systems
Boyd, Mark A.; Bavuso, Salvatore J.
1993-01-01
The use of simulation is described and it is contrasted to analytical solution techniques for evaluation of analytical reliability models. The role importance sampling plays in simulation of models of this type was also discussed. The simulator tool used for our analysis is described. Finally, the use of the simulator tool was demonstrated by applying it to evaluate the reliability of a fault tolerant hypercube multiprocessor intended for spacecraft designed for long duration missions. The reliability analysis was used to highlight the advantages and disadvantages offered by simulation over analytical solution of Markovian and non-Markovian reliability models.
A new model to simulate impact breakup
Cordelli, Alessandro; Farinella, Paolo
1997-12-01
We have developed a preliminary version of a new type of code to simulate the outcomes of impacts between solid bodies, which we plan to further refine for application to both asteroid science and space debris studies. In the current code, colliding objects are modeled as two-dimensional arrays of finite elements, which can interact with each other in both an elastic and a shock-wave regime. The finite elements are hard spheres with a given value for mass and radius. When two of them come into contact the laws of inelastic scattering are applied, thus giving rise to the propagation of shock waves. Moreover each spherical element interacts elastically with its nearest neighbours. The interaction force corresponds to that of a spring having an equilibrium length equal to the lattice spacing, and results into the propagation of elastic waves in the lattice. Dissipation effects are modeled by means of a dissipative force term proportional to the relative velocity, with a given characteristic time of decay. The possible occurrence of fractures in the material is modeled by assuming that when the distance of two neighbouring elements exceeds a threshold value, the binding force between them disappears for ever. This model requires finding a plausible correspondence between the input parameters appearing in the equations of motion, and the physical properties of real solid materials. Some of the required links are quite obvious (e.g., the relationship between mass of the elements and elastic constant on one side, and material density and sound velocity on the other side), some others a priori are unclear, and additional hypotheses on them must be made (e.g., on the restitution coefficient of inelastic scattering). Despite the preliminary character of the model, we have obtained some interesting results, which appear to mimic in a realistic way the outcomes of actual impacts. For instance, we have observed the formation of craters and fractures, and (for high impact
Accuracy of three-dimensional soft tissue simulation in bimaxillary osteotomies
Liebregts, J.; Xi, T.; Timmermans, M.; Koning, M.J.J. de; Berge, S.J.; Hoppenreijs, T.J.M.; Maal, T.J.
2015-01-01
The purpose of this study was to evaluate the accuracy of an algorithm based on the mass tensor model (MTM) for computerized 3D simulation of soft-tissue changes following bimaxillary osteotomy, and to identify patient and surgery-related factors that may affect the accuracy of the simulation. Sixty
Accuracy of three-dimensional soft tissue simulation in bimaxillary osteotomies
Liebregts, J.; Xi, T.; Timmermans, M.; Koning, M.J.J. de; Berge, S.J.; Hoppenreijs, T.J.M.; Maal, T.J.
2015-01-01
The purpose of this study was to evaluate the accuracy of an algorithm based on the mass tensor model (MTM) for computerized 3D simulation of soft-tissue changes following bimaxillary osteotomy, and to identify patient and surgery-related factors that may affect the accuracy of the simulation. Sixty
Beyond Modeling: All-Atom Olfactory Receptor Model Simulations
Directory of Open Access Journals (Sweden)
Peter C Lai
2012-05-01
Full Text Available Olfactory receptors (ORs are a type of GTP-binding protein-coupled receptor (GPCR. These receptors are responsible for mediating the sense of smell through their interaction with odor ligands. OR-odorant interactions marks the first step in the process that leads to olfaction. Computational studies on model OR structures can validate experimental functional studies as well as generate focused and novel hypotheses for further bench investigation by providing a view of these interactions at the molecular level. Here we have shown the specific advantages of simulating the dynamic environment that is associated with OR-odorant interactions. We present a rigorous methodology that ranges from the creation of a computationally-derived model of an olfactory receptor to simulating the interactions between an OR and an odorant molecule. Given the ubiquitous occurrence of GPCRs in the membranes of cells, we anticipate that our OR-developed methodology will serve as a model for the computational structural biology of all GPCRs.
Computerizing primary schools in rural kenya
DEFF Research Database (Denmark)
Ogembo, J.G.; Ngugi, B.; Pelowski, Matthew John
2012-01-01
This paper investigates the outstanding challenges facing primary schools' computerization in rural Kenya. Computerization of schools is often envisaged as a 'magic', or at least a particularly efficient, solution to many of the problems that developing countries face in improving primary school...
Resources for Improving Computerized Learning Environments.
Yeaman, Andrew R. J.
1989-01-01
Presents an annotated review of human factors literature that discusses computerized environments. Topics discussed include the application of office automation practices to educational environments; video display terminal (VDT) workstations; health and safety hazards; planning educational facilities; ergonomics in computerized offices; and…
The Evaluation of SISMAKOM (Computerized SDI Project).
University of Science, Penang (Malaysia).
A survey of 88 users of SISMAKOM, a computerized selective dissemination of information (SDI) and document delivery service provided by the Universiti Sains Malaysia and four other Malaysian universities, was conducted in August 1982 in order to collect data about SISMAKOM and to assess the value of a computerized SDI service in a developing…
Computerized Sociometric Assessment for Preschool Children
Endedijk, Hinke M.; Cillessen, Antonius H. N.
2015-01-01
In preschool classes, sociometric peer ratings are used to measure children's peer relationships. The current study examined a computerized version of preschool sociometric ratings. The psychometric properties were compared of computerized sociometric ratings and traditional peer ratings for preschoolers. The distributions, inter-item…
Aero-acoustic modeling using large eddy simulation
DEFF Research Database (Denmark)
Shen, Wen Zhong; Sørensen, Jens Nørkær
2007-01-01
The splitting technique for aero-acoustic computations is extended to simulate three-dimensional flow and acoustic waves from airfoils. The aero-acoustic model is coupled to a sub-grid-scale turbulence model for Large-Eddy Simulations. In the first test case, the model is applied to compute laminar...
IDEF method-based simulation model design and development framework
Directory of Open Access Journals (Sweden)
Ki-Young Jeong
2009-09-01
Full Text Available The purpose of this study is to provide an IDEF method-based integrated framework for a business process simulation model to reduce the model development time by increasing the communication and knowledge reusability during a simulation project. In this framework, simulation requirements are collected by a function modeling method (IDEF0 and a process modeling method (IDEF3. Based on these requirements, a common data model is constructed using the IDEF1X method. From this reusable data model, multiple simulation models are automatically generated using a database-driven simulation model development approach. The framework is claimed to help both requirement collection and experimentation phases during a simulation project by improving system knowledge, model reusability, and maintainability through the systematic use of three descriptive IDEF methods and the features of the relational database technologies. A complex semiconductor fabrication case study was used as a testbed to evaluate and illustrate the concepts and the framework. Two different simulation software products were used to develop and control the semiconductor model from the same knowledge base. The case study empirically showed that this framework could help improve the simulation project processes by using IDEF-based descriptive models and the relational database technology. Authors also concluded that this framework could be easily applied to other analytical model generation by separating the logic from the data.
Simulation Modeling of a Facility Layout in Operations Management Classes
Yazici, Hulya Julie
2006-01-01
Teaching quantitative courses can be challenging. Similarly, layout modeling and lean production concepts can be difficult to grasp in an introductory OM (operations management) class. This article describes a simulation model developed in PROMODEL to facilitate the learning of layout modeling and lean manufacturing. Simulation allows for the…
Maneuver simulation model of an experimental hovercraft for the Antarctic
Murao, Rinichi
Results of an investigation of a hovercraft model designed for Antarctic conditions are presented. The buoyancy characteristics, the propellant control system, and simulation model control are examined. An ACV (air cushion vehicle) model of the hovercraft is used to examine the flexibility and friction of the skirt. Simulation results are presented which show the performance of the hovercraft.
Quantification of Modelling Uncertainties in Turbulent Flow Simulations
Edeling, W.N.
2015-01-01
The goal of this thesis is to make predictive simulations with Reynolds-Averaged Navier-Stokes (RANS) turbulence models, i.e. simulations with a systematic treatment of model and data uncertainties and their propagation through a computational model to produce predictions of quantities of interest w
Quantification of Modelling Uncertainties in Turbulent Flow Simulations
Edeling, W.N.
2015-01-01
The goal of this thesis is to make predictive simulations with Reynolds-Averaged Navier-Stokes (RANS) turbulence models, i.e. simulations with a systematic treatment of model and data uncertainties and their propagation through a computational model to produce predictions of quantities of interest
Simulation Modeling of a Facility Layout in Operations Management Classes
Yazici, Hulya Julie
2006-01-01
Teaching quantitative courses can be challenging. Similarly, layout modeling and lean production concepts can be difficult to grasp in an introductory OM (operations management) class. This article describes a simulation model developed in PROMODEL to facilitate the learning of layout modeling and lean manufacturing. Simulation allows for the…
Historical Development of Simulation Models of Recreation Use
Jan W. van Wagtendonk; David N. Cole
2005-01-01
The potential utility of modeling as a park and wilderness management tool has been recognized for decades. Romesburg (1974) explored how mathematical decision modeling could be used to improve decisions about regulation of wilderness use. Cesario (1975) described a computer simulation modeling approach that utilized GPSS (General Purpose Systems Simulator), a...
A simulation model of a star computer network
Gomaa, H
1979-01-01
A simulation model of the CERN (European Organization for Nuclear Research) SPS star computer network is described. The model concentrates on simulating the message handling computer, through which all messages in the network pass. The implementation of the model and its calibration are also described. (6 refs).
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Water yield and sediment yield in the Teba catchment, Spain, were simulated using SWRRB (Simulator for Water Resources in Rural Basins) model. The model is composed of 198 mathematical equations. About 120 items (variables) were input for the simulation, including meteorological and climatic factors, hydrologic factors, topographic factors, parent materials, soils, vegetation, human activities, etc. The simulated results involved surface runoff, subsurface runoff, sediment, peak flow, evapotranspiration, soil water, total biomass,etc. Careful and thorough input data preparation and repeated simulation experiments are the key to get the accurate results. In this work the simulation accuracy for annual water yield prediction reached to 83.68%.``
Four Models of In Situ Simulation
DEFF Research Database (Denmark)
Musaeus, Peter; Krogh, Kristian; Paltved, Charlotte
2014-01-01
that there are four fruitful approaches to in situ simulation: (1) In situ simulation informed by reported critical incidents and adverse events from emergency departments (ED) in which team training is about to be conducted to write scenarios. (2) In situ simulation through ethnographic studies at the ED. (3) Using...... prewritten scenarios from the simulation lab and transferring them to in situ simulation. (4) Action research – insider or participant action research to obtain in-depth understanding of team processes to guide scenario design. We evaluate the approach relying on Marks’ et al. taxonomy that posits...... the following processes: Transition processes, Action processes and Interpersonal processes. Design and purpose This abstract suggests four approaches to in situ simulation. A pilot study will evaluate the different approaches in two emergency departments in the Central Region of Denmark. Methods The typology...
A New Model for Simulating TSS Washoff in Urban Areas
Directory of Open Access Journals (Sweden)
E. Crobeddu
2011-01-01
Full Text Available This paper presents the formulation and validation of the conceptual Runoff Quality Simulation Model (RQSM that was developed to simulate the erosion and transport of solid particles in urban areas. The RQSM assumes that solid particle accumulation on pervious and impervious areas is infinite. The RQSM simulates soil erosion using rainfall kinetic energy and solid particle transport with linear system theory. A sensitivity analysis was conducted on the RQSM to show the influence of each parameter on the simulated load. Total suspended solid (TSS loads monitored at the outlet of the borough of Verdun in Canada and at three catchment outlets of the City of Champaign in the United States were used to validate the RQSM. TSS loads simulated by the RQSM were compared to measured loads and to loads simulated by the Rating Curve model and the Exponential model of the SWMM software. The simulation performance of the RQSM was comparable to the Exponential and Rating Curve models.
An Integrated Approach to Flexible Modelling and Animated Simulation
Institute of Scientific and Technical Information of China (English)
Li Shuliang; Wu Zhenye
1994-01-01
Based on the software support of SIMAN/CINEMA, this paper presents an integrated approach to flexible modelling and simulation with animation. The methodology provides a structured way of integrating mathematical and logical model, statistical experinentation, and statistical analysis with computer animation. Within this methodology, an animated simulation study is separated into six different activities: simulation objectives identification , system model development, simulation experiment specification, animation layout construction, real-time simulation and animation run, and output data analysis. These six activities are objectives driven, relatively independent, and integrate through software organization and simulation files. The key ideas behind this methodology are objectives orientation, modelling flexibility,simulation and animation integration, and application tailorability. Though the methodology is closely related to SIMAN/CINEMA, it can be extended to other software environments.
Evaluation of Marine Corps Manpower Computer Simulation Model
2016-12-01
MARINE CORPS MANPOWER COMPUTER SIMULATION MODEL by Eric S. Anderson December 2016 Thesis Advisor: Arnold Buss Second Reader: Neil Rowe...Master’s thesis 4. TITLE AND SUBTITLE EVALUATION OF MARINE CORPS MANPOWER COMPUTER SIMULATION MODEL 5. FUNDING NUMBERS ACCT: 622716 JON...overall end strength are maintained. To assist their mission, an agent-based computer simulation model was developed in the Java computer language
Business Process Simulation: Requirements for Business and Resource Models
Directory of Open Access Journals (Sweden)
Audrius Rima
2015-07-01
Full Text Available The purpose of Business Process Model and Notation (BPMN is to provide easily understandable graphical representation of business process. Thus BPMN is widely used and applied in various areas one of them being a business process simulation. This paper addresses some BPMN model based business process simulation problems. The paper formulate requirements for business process and resource models in enabling their use for business process simulation.
Discrete Event Simulation Modeling and Analysis of Key Leader Engagements
2012-06-01
SIMULATION MODELING AND ANALYSIS OF KEY LEADER ENGAGEMENTS by Clifford C. Wakeman June 2012 Thesis Co-Advisors: Arnold H. Buss Susan...DATE June 2012 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Discrete Event Simulation Modeling and Analysis of Key...for public release; distribution is unlimited DISCRETE EVENT SIMULATION MODELING AND ANALYSIS OF KEY LEADER ENGAGEMENTS Clifford C. Wakeman
The COD Model: Simulating Workgroup Performance
Biggiero, Lucio; Sevi, Enrico
Though the question of the determinants of workgroup performance is one of the most central in organization science, precise theoretical frameworks and formal demonstrations are still missing. In order to fill in this gap the COD agent-based simulation model is here presented and used to study the effects of task interdependence and bounded rationality on workgroup performance. The first relevant finding is an algorithmic demonstration of the ordering of interdependencies in terms of complexity, showing that the parallel mode is the most simplex, followed by the sequential and then by the reciprocal. This result is far from being new in organization science, but what is remarkable is that now it has the strength of an algorithmic demonstration instead of being based on the authoritativeness of some scholar or on some episodic empirical finding. The second important result is that the progressive introduction of realistic limits to agents' rationality dramatically reduces workgroup performance and addresses to a rather interesting result: when agents' rationality is severely bounded simple norms work better than complex norms. The third main finding is that when the complexity of interdependence is high, then the appropriate coordination mechanism is agents' direct and active collaboration, which means teamwork.
Diversity modelling for electrical power system simulation
Sharip, R. M.; Abu Zarim, M. A. U. A.
2013-12-01
This paper considers diversity of generation and demand profiles against the different future energy scenarios and evaluates these on a technical basis. Compared to previous studies, this research applied a forecasting concept based on possible growth rates from publically electrical distribution scenarios concerning the UK. These scenarios were created by different bodies considering aspects such as environment, policy, regulation, economic and technical. In line with these scenarios, forecasting is on a long term timescale (up to every ten years from 2020 until 2050) in order to create a possible output of generation mix and demand profiles to be used as an appropriate boundary condition for the network simulation. The network considered is a segment of rural LV populated with a mixture of different housing types. The profiles for the 'future' energy and demand have been successfully modelled by applying a forecasting method. The network results under these profiles shows for the cases studied that even though the value of the power produced from each Micro-generation is often in line with the demand requirements of an individual dwelling there will be no problems arising from high penetration of Micro-generation and demand side management for each dwellings considered. The results obtained highlight the technical issues/changes for energy delivery and management to rural customers under the future energy scenarios.
Graph model of behavior simulator. [Interactive simulator developed as part of UCLA SARA system
Energy Technology Data Exchange (ETDEWEB)
Razouk, R.R.; Estrin, G.
1966-01-01
An interactive simulator developed at UCLA as part of the SARA system is described. This simulator, in conjunction with other design tools of the SARA system, allows the user to model the behavior of the system being designed at various levels of detail. The models which drive the simulator are control graphs and associated data graphs. The simulator uses the control graph to express synchronization of sequences of events. Initiation of any control node triggers the simulator to call on the data graph model to provide interpretation of a process at a desired level of abstraction. The simulator gives the user the capability to examine, or modify, the state of the control and data graphs during a simulation. 8 figures.
Modeling, Simulation and Position Control of 3DOF Articulated Manipulator
Directory of Open Access Journals (Sweden)
Hossein Sadegh Lafmejani
2014-08-01
Full Text Available In this paper, the modeling, simulation and control of 3 degrees of freedom articulated robotic manipulator have been studied. First, we extracted kinematics and dynamics equations of the mentioned manipulator by using the Lagrange method. In order to validate the analytical model of the manipulator we compared the model simulated in the simulation environment of Matlab with the model was simulated with the SimMechanics toolbox. A sample path has been designed for analyzing the tracking subject. The system has been linearized with feedback linearization and then a PID controller was applied to track a reference trajectory. Finally, the control results have been compared with a nonlinear PID controller.
Institute of Scientific and Technical Information of China (English)
罗芬; 丁树良; 王晓庆
2012-01-01
Item selection strategy (ISS) is a core component in Computerized Adaptive Testing (CAT). Polytomous items can provide more information about examinee compared with dichotomous items, and adopting polytomously scored items in test is a research direction of CAT. As we know, the most widely used ISS is the maximum Fisher information (MFI) criterion, which raises concerns about cost-efficiency of the pool utilization and poses security risks for CAT programs. Chang & Ying (1999) and Chang, Qian, & Ying (2001) proposed two alternative item selection procedures, the a-stratified method (a-STR) and the a-stratified with b blocking method (&-STR) based on dichotomous model, with the goal to remedy the problems of item overexposure and item underexposure produced by MFI. However, the technology of a-STR and fc-STR is static because the items are stratified according to the given information at the beginning of test. Based on graded response model (GRM), a technique of the reduction dimensionality of difficulty (or step) parameters was employed[0] to construct some ISSs recently. The limitation of this dimension reduction technique is that it loses a lot of information. Thus, in order to improve MFI, two new item selection methods are proposed based on GRM: (1) modify the technique of the reduction dimensionality of difficulty (or step) parameters by integrating the interval estimation; (2) dynamic a-STR and dynamic fc-STR methods are implemented in the testing process. On one hand, these new ISSs can avoid and remedy the limitations of MFI and make good use of the advantages of the Fisher information function (FIF); FIF compresses all item parameters and ability parameters, so it is a comprehensive tool for all parameters in nature. On the other hand, the new ISSs employ the property that FIF could represent the inverse of the variance of the ability estimation, let ￡ be the square root of the reciprocal ofthe Fisher information, d be the absolute deviation between the
Energy Technology Data Exchange (ETDEWEB)
Xu Song; Song Fei [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China); Li Zhizhong [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China)], E-mail: zzli@tsinghua.edu.cn; Zhao Qianyi; Luo Wei [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China); He Xuhong [Scanpower Risk Management China Inc., Towercrest International Plaza, No. 3 Maizidian West Road, Chaoyang District, Beijing 100016 (China); Salvendy, Gavriel [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China)
2008-10-15
Emergency operating procedures (EOPs) are widely used in nuclear power plants (NPPs). With the development of information technology, computerized EOPs are taking the place of paper-based ones. Unlike paper-based EOPs, the industrial practice of computerized EOPs is still quite limited. Ergonomics issues of computerized EOPs have not been studied adequately. This study focuses on the effects of EOP presentation style, task complexity, and training level on the performance of the operators in the execution of computerized EOPs. One simulated computerized EOP system was developed to present two EOPs, each with different task complexity levels, by two presentation styles (Style A: one- and two-dimensional flowcharts combination; Style B: two-dimensional flowchart and success logic tree combination). Forty subjects participated in the experiment of EOP execution using the simulated system. Statistical analysis of the experimental results indicates that: (1) complexity, presentation style, and training level all can significantly influence the error rate. High-complexity tasks and lack of sufficient training may lead to a higher error rate. Style B caused a significantly higher error rate than style A did in the skilled phase. So the designers of computerized procedures should take the presentation styles of EOPs into account. (2) Task complexity and training level can significantly influence operation time. No significant difference was found in operation time between the two presentation styles. (3) Training level can also significantly influence the subjective workload of EOPs operations. This implies that adequate training is very important for the performance of computerized EOPs even if emergency responses with computerized EOPs are much more simple and easy than that with paper-based EOPs.
Runoff Simulation of Shitoukoumen Reservoir Basin Based on SWAT Model
Institute of Scientific and Technical Information of China (English)
XIE; Miao; LI; Hong-yan; LIU; Tie-juan; RU; Shi-rong
2012-01-01
[Objective]The study aimed to simulate the runoff of Shitoukoumen Reservoir basin by using SWAT model. [Method] Based on DEM elevation, land use type, soil type and hydrometeorological data, SWAT model, a distributed hydrological model was established to simulate the monthly runoff of Shitoukoumen Reservoir basin, and the years 2006 and 2010 were chosen as the calibration and validation period respectively. [Result] The simulation results indicated that SWAT model could be used to simulate the runoff of Shitoukoumen Reservoir basin, and the simulation effect was good. However, the response of the model to local rainstorm was not obvious, so that the actual runoff in June and July of 2010 was abnormally higher than the simulation value. [Conclusion] The research could provide theoretical references for the plan and management of water resources in Shitoukoumen Reservoir basin in future.
A model for educational simulation of infant cardiovascular physiology.
Goodwin, Jane A; van Meurs, Willem L; Sá Couto, Carla D; Beneken, Jan E W; Graves, Shirley A
2004-12-01
Full-body patient simulators provide the technology and the environment necessary for excellent clinical education while eliminating risk to the patient. The extension of simulator-based training into management of basic and critical situations in complex patient populations is natural. We describe the derivation of an infant cardiovascular model through the redefinition of a complete set of parameters for an existing adult model. Specifically, we document a stepwise parameter estimation process, explicit simplifying assumptions, and sources for these parameters. The simulated vital signs are within the target hemodynamic variables, and the simulated systemic arterial pressure wave form and left ventricular pressure volume loop are realistic. The system reacts appropriately to blood loss, and incorporation of aortic stenosis is straightforward. This infant cardiovascular model can form the basis for screen-based educational simulations. The model is also an essential step in attaining a full-body, model-driven infant simulator.
Institute of Scientific and Technical Information of China (English)
杨贵兴
2015-01-01
Accounting, information science, economics, computer science, management science and other disciplines are the accounting computerization in the subject, computerized accounting not only covers the content is wide, its are very strong theoretical, practical and comprehensive. Accounting is a practical professional, practical skills training is a compulsory course of accounting practitioners. If the accounting practitioners who simply rely on theoretical knowledge to take part in social work, it can't meet the demand for accounting talents in today's society.%会计学、信息学、经济学、计算机学、管理学等多种学科都是会计电算化涵盖的学科，会计电算化不仅涵盖内容广，其理论性、实践性和综合性也非常强。基于会计专业是一个实践性很强的一个专业，实践技能培训是会计工作从业者上岗之前必须要上的一门课程。如果会计从业者只是单纯的依靠在学校里学的理论知识去参加社会工作，此种做法是不能满足当今社会对会计人才需求的。
Qualitative and Quantitative Integrated Modeling for Stochastic Simulation and Optimization
Directory of Open Access Journals (Sweden)
Xuefeng Yan
2013-01-01
Full Text Available The simulation and optimization of an actual physics system are usually constructed based on the stochastic models, which have both qualitative and quantitative characteristics inherently. Most modeling specifications and frameworks find it difficult to describe the qualitative model directly. In order to deal with the expert knowledge, uncertain reasoning, and other qualitative information, a qualitative and quantitative combined modeling specification was proposed based on a hierarchical model structure framework. The new modeling approach is based on a hierarchical model structure which includes the meta-meta model, the meta-model and the high-level model. A description logic system is defined for formal definition and verification of the new modeling specification. A stochastic defense simulation was developed to illustrate how to model the system and optimize the result. The result shows that the proposed method can describe the complex system more comprehensively, and the survival probability of the target is higher by introducing qualitative models into quantitative simulation.
Theory, modeling and simulation of superconducting qubits
Energy Technology Data Exchange (ETDEWEB)
Berman, Gennady P [Los Alamos National Laboratory; Kamenev, Dmitry I [Los Alamos National Laboratory; Chumak, Alexander [INSTIT OF PHYSICS, KIEV; Kinion, Carin [LLNL; Tsifrinovich, Vladimir [POLYTECHNIC INSTIT OF NYU
2011-01-13
We analyze the dynamics of a qubit-resonator system coupled with a thermal bath and external electromagnetic fields. Using the evolution equations for the set of Heisenberg operators that describe the whole system, we derive an expression for the resonator field, that includes the resonator-drive, the resonator-bath, and resonator-qubit interactions. The renormalization of the resonator frequency, caused by the qubit-resonator interaction, is accounted for. Using the solutions for the resonator field, we derive the equation that describes the qubit dynamics. The dependence of the qubit evolution during the measurement time on the fidelity of a single-shot measurement is studied. The relation between the fidelity and measurement time is shown explicitly. We proposed a novel adiabatic method for the phase qubit measurement. The method utilizes a low-frequency, quasi-classical resonator inductively coupled to the qubit. The resonator modulates the qubit energy, and the back reaction of the qubit causes a shift in the phase of the resonator. The resonator phase shift can be used to determine the qubit state. We have simulated this measurement taking into the account the energy levels outside the phase qubit manifold. We have shown that, for qubit frequencies in the range of 8-12GHZ, a resonator frequency of 500 MHz and a measurement time of 100 ns, the phase difference between the two qubit states is greater than 0.2 rad. This phase difference exceeds the measurement uncertainty, and can be detected using a classical phase-meter. A fidelity of 0.9999 can be achieved for a relaxation time of 0.5 ms. We also model and simulate a microstrip-SQUID amplifier of frequency about 500 MHz, which could be used to amplify the resonator oscillations in the phase qubit adiabatic measurement. The voltage gain and the amplifier noise temperature are calculated. We simulate the preparation of a generalized Bell state and compute the relaxation times required for achieving high
Theory, modeling and simulation of superconducting qubits
Energy Technology Data Exchange (ETDEWEB)
Berman, Gennady P [Los Alamos National Laboratory; Kamenev, Dmitry I [Los Alamos National Laboratory; Chumak, Alexander [INSTIT OF PHYSICS, KIEV; Kinion, Carin [LLNL; Tsifrinovich, Vladimir [POLYTECHNIC INSTIT OF NYU
2011-01-13
We analyze the dynamics of a qubit-resonator system coupled with a thermal bath and external electromagnetic fields. Using the evolution equations for the set of Heisenberg operators that describe the whole system, we derive an expression for the resonator field, that includes the resonator-drive, the resonator-bath, and resonator-qubit interactions. The renormalization of the resonator frequency, caused by the qubit-resonator interaction, is accounted for. Using the solutions for the resonator field, we derive the equation that describes the qubit dynamics. The dependence of the qubit evolution during the measurement time on the fidelity of a single-shot measurement is studied. The relation between the fidelity and measurement time is shown explicitly. We proposed a novel adiabatic method for the phase qubit measurement. The method utilizes a low-frequency, quasi-classical resonator inductively coupled to the qubit. The resonator modulates the qubit energy, and the back reaction of the qubit causes a shift in the phase of the resonator. The resonator phase shift can be used to determine the qubit state. We have simulated this measurement taking into the account the energy levels outside the phase qubit manifold. We have shown that, for qubit frequencies in the range of 8-12GHZ, a resonator frequency of 500 MHz and a measurement time of 100 ns, the phase difference between the two qubit states is greater than 0.2 rad. This phase difference exceeds the measurement uncertainty, and can be detected using a classical phase-meter. A fidelity of 0.9999 can be achieved for a relaxation time of 0.5 ms. We also model and simulate a microstrip-SQUID amplifier of frequency about 500 MHz, which could be used to amplify the resonator oscillations in the phase qubit adiabatic measurement. The voltage gain and the amplifier noise temperature are calculated. We simulate the preparation of a generalized Bell state and compute the relaxation times required for achieving high
MODEL OF HEAT SIMULATOR FOR DATA CENTERS
Directory of Open Access Journals (Sweden)
Jan Novotný
2016-08-01
Full Text Available The aim of this paper is to present a design and a development of a heat simulator, which will be used for a flow research in data centers. The designed heat simulator is based on an ideological basis of four-processor 1U Supermicro server. The designed heat simulator enables to control the flow and heat output within the range of 10–100 %. The paper covers also the results of testing measurements of mass flow rates and heat flow rates in the simulator. The flow field at the outlet of the server was measured by the stereo PIV method. The heat flow rate was determined, based on measuring the temperature field at the inlet and outlet of the simulator and known mass flow rate.
SiSeRHMap v1.0: a simulator for mapped seismic response using a hybrid model
Grelle, Gerardo; Bonito, Laura; Lampasi, Alessandro; Revellino, Paola; Guerriero, Luigi; Sappa, Giuseppe; Guadagno, Francesco Maria
2016-04-01
The SiSeRHMap (simulator for mapped seismic response using a hybrid model) is a computerized methodology capable of elaborating prediction maps of seismic response in terms of acceleration spectra. It was realized on the basis of a hybrid model which combines different approaches and models in a new and non-conventional way. These approaches and models are organized in a code architecture composed of five interdependent modules. A GIS (geographic information system) cubic model (GCM), which is a layered computational structure based on the concept of lithodynamic units and zones, aims at reproducing a parameterized layered subsoil model. A meta-modelling process confers a hybrid nature to the methodology. In this process, the one-dimensional (1-D) linear equivalent analysis produces acceleration response spectra for a specified number of site profiles using one or more input motions. The shear wave velocity-thickness profiles, defined as trainers, are randomly selected in each zone. Subsequently, a numerical adaptive simulation model (Emul-spectra) is optimized on the above trainer acceleration response spectra by means of a dedicated evolutionary algorithm (EA) and the Levenberg-Marquardt algorithm (LMA) as the final optimizer. In the final step, the GCM maps executor module produces a serial map set of a stratigraphic seismic response at different periods, grid solving the calibrated Emul-spectra model. In addition, the spectra topographic amplification is also computed by means of a 3-D validated numerical prediction model. This model is built to match the results of the numerical simulations related to isolate reliefs using GIS morphometric data. In this way, different sets of seismic response maps are developed on which maps of design acceleration response spectra are also defined by means of an enveloping technique.
Research on system architecture of modeling and simulation
Institute of Scientific and Technical Information of China (English)
WANG Jiangyun; WANG Xingren
2007-01-01
The modeling and simulation(M&S)architecture describes and defines the relationship between the difeerent parts of a simulation.The simulation system architecture and simulation support platform architecture are discussed separately.The simulation support platform architecture consists of the management layer,the resource layer,the communication layer,the application layer and the infrastructure layer.The best Wav is to design and realize the M&S collaborative environment for simulation support platform in the resource-communication-application three-dimension space.
Relative importance of secondary settling tank models in WWTP simulations
DEFF Research Database (Denmark)
Ramin, Elham; Flores-Alsina, Xavier; Sin, Gürkan
2012-01-01
Results obtained in a study using the Benchmark Simulation Model No. 1 (BSM1) show that a one-dimensional secondary settling tank (1-D SST) model structure and its parameters are among the most significant sources of uncertainty in wastewater treatment plant (WWTP) simulations [Ramin et al., 2011......]. The sensitivity results consistently indicate that the prediction of sludge production is most sensitive to the variation of the settling parameters. In the present study, we use the Benchmark Simulation Model No. 2 (BSM2), a plant-wide benchmark, that combines the Activated Sludge Model No. 1 (ASM1......) with the Anaerobic Digestion Model No. 1 (ADM1). We use BSM2 as a vehicle to compare two different 1-D SST models, and to assess the relative significance of their performance on WWTP simulation model outputs. The two 1-D SST models assessed include the firstorder model by Takács et al. [1991] and the second...
Institute of Scientific and Technical Information of China (English)
高秀满
2011-01-01
针对传统粗纱机机械结构的复杂性,分析了粗纱卷绕成形的原理,提出多电动机传动粗纱机的逐级设计方案,取消了繁杂的机械结构,其相应的功能由计算机控制多个电动机完成.分析3种卷绕数学模型建立方法的区别,并由此建立粗纱卷绕成形数学模型,给出每层厚度和筒管直径对纺纱张力影响的趋势线,特别是从实际使用的角度分析了理想换向禁停的区域,实现了换向禁停数学模型其包括大小纱不同和换向前后不同,为实现良好的成形提供了保证.同时介绍了电脑粗纱机与传统粗纱机参数调整方法的区别,认为电脑粗纱机可以方便地设置、更改参数,变换粗纱品种,具有较高的实用价值.%According to the complexity of the mechanical structure of conventional fly frame, the paper analyzed the shaping principle of roving winding, and put forward the overall design scheme of multi-motor driving fly frame, eliminating the multifarious mechanical structure whose corresponding function is fulfilled by several motors controlled by a computer. It discussed the differences of three winding mathematic models, and established a mathematic model of roving winding accordingly. The influence of average thickness of each roving layer and the diameter of bare bobbin on the yarn tension was presented, as well as the related curves. Especially, from the point of view of practical use, the zone of ideal reversing and stop-inhibition was analyzed, and a mathematical model of reversing and stop-inhibition was developed, and suitable for yarns of various counts and reversing either back or forward, thus providing a guarantee for good shaping. The differences of parameters adjustment methods between the computerized fly frame and the conventional one were introduced, showing that the computerized fly frame has higher practical value for its convenience in parameter presetting and adjusting, and change of roving varieties as
Scintillation detectors in computerized tomography
Energy Technology Data Exchange (ETDEWEB)
Gilar, O.; Pavlicek, Z.; Jursova, L. (Tesla, Premysleni (Czechoslovakia). Vyzkumny Ustav Pristroju Jaderne Techniky)
1984-07-01
A new scintillator, Bi/sub 4/Ge/sub 3/O/sub 12/ (BGO), was tested for use in the detection part of computerized tomographs. In comparison with the NaI(Tl) scintillator it has a three-fold mass stopping power and allows the detection of medium and high energy gamma radiation with a higher detection efficiency, i.e., for the same detection efficiency its size is much smaller. Some other mechanical, physical and optical parameters of the BGO scintillator are given. BGO is prospective for use in high energy spectrometry and may replace NaI(Tl) wherever the following parameters are significant: crystal size, detection efficiency for gamma radiation, and good spatial resolution.
Psychometrics behind Computerized Adaptive Testing.
Chang, Hua-Hua
2015-03-01
The paper provides a survey of 18 years' progress that my colleagues, students (both former and current) and I made in a prominent research area in Psychometrics-Computerized Adaptive Testing (CAT). We start with a historical review of the establishment of a large sample foundation for CAT. It is worth noting that the asymptotic results were derived under the framework of Martingale Theory, a very theoretical perspective of Probability Theory, which may seem unrelated to educational and psychological testing. In addition, we address a number of issues that emerged from large scale implementation and show that how theoretical works can be helpful to solve the problems. Finally, we propose that CAT technology can be very useful to support individualized instruction on a mass scale. We show that even paper and pencil based tests can be made adaptive to support classroom teaching.
Optimisation of a Crossdocking Distribution Centre Simulation Model
Adewunmi, Adrian
2010-01-01
This paper reports on continuing research into the modelling of an order picking process within a Crossdocking distribution centre using Simulation Optimisation. The aim of this project is to optimise a discrete event simulation model and to understand factors that affect finding its optimal performance. Our initial investigation revealed that the precision of the selected simulation output performance measure and the number of replications required for the evaluation of the optimisation objective function through simulation influences the ability of the optimisation technique. We experimented with Common Random Numbers, in order to improve the precision of our simulation output performance measure, and intended to use the number of replications utilised for this purpose as the initial number of replications for the optimisation of our Crossdocking distribution centre simulation model. Our results demonstrate that we can improve the precision of our selected simulation output performance measure value using C...
On-line simulations of models for backward masking.
Francis, Gregory
2003-11-01
Five simulations of quantitative models of visual backward masking are available on the Internet at http://www.psych.purdue.edu/-gfrancis/Publications/BackwardMasking/. The simulations can be run in a Web browser that supports the Java programming language. This article describes the motivation for making the simulations available and gives a brief introduction as to how the simulations are used. The source code is available on the Web page, and this article describes how the code is organized.
Theory of compressive modeling and simulation
Szu, Harold; Cha, Jae; Espinola, Richard L.; Krapels, Keith
2013-05-01
Modeling and Simulation (M&S) has been evolving along two general directions: (i) data-rich approach suffering the curse of dimensionality and (ii) equation-rich approach suffering computing power and turnaround time. We suggest a third approach. We call it (iii) compressive M&S (CM&S); because the basic Minimum Free-Helmholtz Energy (MFE) facilitating CM&S can reproduce and generalize Candes, Romberg, Tao & Donoho (CRT&D) Compressive Sensing (CS) paradigm as a linear Lagrange Constraint Neural network (LCNN) algorithm. CM&S based MFE can generalize LCNN to 2nd order as Nonlinear augmented LCNN. For example, during the sunset, we can avoid a reddish bias of sunlight illumination due to a long-range Rayleigh scattering over the horizon. With CM&S we can take instead of day camera, a night vision camera. We decomposed long wave infrared (LWIR) band with filter into 2 vector components (8~10μm and 10~12μm) and used LCNN to find pixel by pixel the map of Emissive-Equivalent Planck Radiation Sources (EPRS). Then, we up-shifted consistently, according to de-mixed sources map, to the sub-micron RGB color image. Moreover, the night vision imaging can also be down-shifted at Passive Millimeter Wave (PMMW) imaging, suffering less blur owing to dusty smokes scattering and enjoying apparent smoothness of surface reflectivity of man-made objects under the Rayleigh resolution. One loses three orders of magnitudes in the spatial Rayleigh resolution; but gains two orders of magnitude in the reflectivity, and gains another two orders in the propagation without obscuring smog . Since CM&S can generate missing data and hard to get dynamic transients, CM&S can reduce unnecessary measurements and their associated cost and computing in the sense of super-saving CS: measuring one & getting one's neighborhood free .
Nanoindentation shape effect: experiments, simulations and modelling
Energy Technology Data Exchange (ETDEWEB)
Calabri, L [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Pugno, N [Department of Structural Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Rota, A [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Marchetto, D [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Valeri, S [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy)
2007-10-03
AFM nanoindentation is nowadays commonly used for the study of mechanical properties of materials at the nanoscale. The investigation of surface hardness of a material using AFM means that the probe has to be able to indent the surface, but also to image it. Usually standard indenters are not sharp enough to obtain high-resolution images, but on the other hand measuring the hardness behaviour of a material with a non-standard sharp indenter gives only comparative results affected by a significant deviation from the commonly used hardness scales. In this paper we try to understand how the shape of the indenter affects the hardness measurement, in order to find a relationship between the measured hardness of a material and the corner angle of a pyramidal indenter. To achieve this we performed a full experimental campaign, indenting the same material with three focused ion beam (FIB) nanofabricated probes with a highly altered corner angle. We then compared the results obtained experimentally with those obtained by numerical simulations, using the finite element method (FEM), and by theoretical models, using a general scaling law for nanoindentation available for indenters with a variable size and shape. The comparison between these three approaches (experimental, numerical and theoretical approaches) reveals a good agreement and allowed us to find a theoretical relationship which links the measured hardness value with the shape of the indenter. The same theoretical approach has also been used to fit the hardness experimental results considering the indentation size effect. In this case we compare the measured data, changing the applied load.
Medical simulation: Overview, and application to wound modelling and management
Directory of Open Access Journals (Sweden)
Dinker R Pai
2012-01-01
Full Text Available Simulation in medical education is progressing in leaps and bounds. The need for simulation in medical education and training is increasing because of a overall increase in the number of medical students vis-à-vis the availability of patients; b increasing awareness among patients of their rights and consequent increase in litigations and c tremendous improvement in simulation technology which makes simulation more and more realistic. Simulation in wound care can be divided into use of simulation in wound modelling (to test the effect of projectiles on the body and simulation for training in wound management. Though this science is still in its infancy, more and more researchers are now devising both low-technology and high-technology (virtual reality simulators in this field. It is believed that simulator training will eventually translate into better wound care in real patients, though this will be the subject of further research.
Towards Automatic Processing of Virtual City Models for Simulations
Piepereit, R.; Schilling, A.; Alam, N.; Wewetzer, M.; Pries, M.; Coors, V.
2016-10-01
Especially in the field of numerical simulations, such as flow and acoustic simulations, the interest in using virtual 3D models to optimize urban systems is increasing. The few instances in which simulations were already carried out in practice have been associated with an extremely high manual and therefore uneconomical effort for the processing of models. Using different ways of capturing models in Geographic Information System (GIS) and Computer Aided Engineering (CAE), increases the already very high complexity of the processing. To obtain virtual 3D models suitable for simulation, we developed a tool for automatic processing with the goal to establish ties between the world of GIS and CAE. In this paper we introduce a way to use Coons surfaces for the automatic processing of building models in LoD2, and investigate ways to simplify LoD3 models in order to reduce unnecessary information for a numerical simulation.
Understanding Emergency Care Delivery through Computer Simulation Modeling.
Laker, Lauren F; Torabi, Elham; France, Daniel J; Froehle, Craig M; Goldlust, Eric J; Hoot, Nathan R; Kasaie, Parastu; Lyons, Michael S; Barg-Walkow, Laura H; Ward, Michael J; Wears, Robert L
2017-08-10
In 2017, Academic Emergency Medicine convened a consensus conference entitled, "Catalyzing System Change through Health Care Simulation: Systems, Competency, and Outcomes." This manuscript, a product of the breakout session on "understanding complex interactions through systems modeling," explores the role that computer simulation modeling can and should play in research and development of emergency care delivery systems. This manuscript discusses areas central to the use of computer simulation modeling in emergency care research. The four central approaches to computer simulation modeling are described (Monte Carlo Simulation, System Dynamics modeling, Discrete-Event Simulation, and Agent Based Simulation), along with problems amenable to their use and relevant examples to emergency care. Also discussed is an introduction to available software modeling platforms and how to explore their use for research, along with a research agenda for computer simulation modeling. Through this manuscript, our goal is to enhance adoption of computer simulation, a set of methods which hold great promise in addressing emergency care organization and design challenges. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
Conceptual Modeling for Discrete-Event Simulation
Robinson, Stewart
2010-01-01
What is a conceptual model? How is conceptual modeling performed in general and in specific modeling domains? What is the role of established approaches in conceptual modeling? This book addresses these issues
Mathematical Simulating Model of Phased-Array Antenna in Multifunction Array Radar
Institute of Scientific and Technical Information of China (English)
无
1999-01-01
A mathematical simulating model of phased-array antenna in multifunction array radar has been approached in this paper, including the mathematical simulating model of plane phased-array pattern, the mathematical simulating model of directionality factor, the mathematical simulating model of array factor, the mathematical simulating model of array element factor and the mathematical simulating model of beam steering.
A Simulation Model Articulation of the REA Ontology
Laurier, Wim; Poels, Geert
This paper demonstrates how the REA enterprise ontology can be used to construct simulation models for business processes, value chains and collaboration spaces in supply chains. These models support various high-level and operational management simulation applications, e.g. the analysis of enterprise sustainability and day-to-day planning. First, the basic constructs of the REA ontology and the ExSpect modelling language for simulation are introduced. Second, collaboration space, value chain and business process models and their conceptual dependencies are shown, using the ExSpect language. Third, an exhibit demonstrates the use of value chain models in predicting the financial performance of an enterprise.
Research on the modeling method of soybean leafs structure simulation
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Leaf is one of the most important organs of soybean. The modeling of soybean leaf structure is useful to research of leaf function. The paper discussed it from two aspects that were distilling method of leaf profile and establishing method of leaf simulation model. It put forward basic method of soybean leaf digital process, and successfully established simulation model of soybean leaf structure based on L-system. It also solved a critical problem in the process of establishing soybean growth simulation model. And the research had guiding significance to establishment of soybean plant model.
Stochastic models to simulate paratuberculosis in dairy herds
DEFF Research Database (Denmark)
Nielsen, S.S.; Weber, M.F.; Kudahl, Anne Margrethe Braad
2011-01-01
Stochastic simulation models are widely accepted as a means of assessing the impact of changes in daily management and the control of different diseases, such as paratuberculosis, in dairy herds. This paper summarises and discusses the assumptions of four stochastic simulation models and their use...... the models are somewhat different in their underlying principles and do put slightly different values on the different strategies, their overall findings are similar. Therefore, simulation models may be useful in planning paratuberculosis strategies in dairy herds, although as with all models caution...
A simulation model for forecasting downhill ski participation
Daniel J. Stynes; Daniel M. Spotts
1980-01-01
The purpose of this paper is to describe progress in the development of a general computer simulation model to forecast future levels of outdoor recreation participation. The model is applied and tested for downhill skiing in Michigan.
Logistics of Trainsets Creation with the Use of Simulation Models
Sedláček, Michal; Pavelka, Hynek
2016-12-01
This paper focuses on rail transport in following the train formation operational processes problem using computer simulations. The problem has been solved using SIMUL8 and applied to specific train formation station in the Czech Republic. The paper describes a proposal simulation model of the train formation work. Experimental modeling with an assessment of achievements and design solution for optimizing of the train formation operational process is also presented.
Modeling and Simulation for Design of Suspended MEMS
2003-05-21
simulating systems with complicated electronics is limited. Exporting reduced-order models to aHDLs enables co-simulation with transistor-level...circuit-level behavioral simulation, the models are implemented in analog hardware description languages ( aHDLs ) or directly in element matrices, both...end of module The physical equations could be implemented in the aHDLs in multiple alternative ways. It has been noticed that the language
Cross-Paradigm Simulation Modeling: Challenges and Successes
2011-12-01
This paper addresses the broad topic area of cross-paradigm simulation modeling with a focus on the discrete-event, system dynamics and agent-based...used in simulation modeling are also discussed, and the implications of these mechanisms for each paradigm is explored....and definitions are presented. The difference between the process-oriented worldview and the event-oriented worldview within discrete-event simulation
Software Requirements Specification Verifiable Fuel Cycle Simulation (VISION) Model
Energy Technology Data Exchange (ETDEWEB)
D. E. Shropshire; W. H. West
2005-11-01
The purpose of this Software Requirements Specification (SRS) is to define the top-level requirements for a Verifiable Fuel Cycle Simulation Model (VISION) of the Advanced Fuel Cycle (AFC). This simulation model is intended to serve a broad systems analysis and study tool applicable to work conducted as part of the AFCI (including costs estimates) and Generation IV reactor development studies.
Learning-Testing Process in Classroom: An Empirical Simulation Model
Buda, Rodolphe
2009-01-01
This paper presents an empirical micro-simulation model of the teaching and the testing process in the classroom (Programs and sample data are available--the actual names of pupils have been hidden). It is a non-econometric micro-simulation model describing informational behaviors of the pupils, based on the observation of the pupils'…
Active site modeling in copper azurin molecular dynamics simulations
Rizzuti, B; Swart, M; Sportelli, L; Guzzi, R
2004-01-01
Active site modeling in molecular dynamics simulations is investigated for the reduced state of copper azurin. Five simulation runs (5 ns each) were performed at room temperature to study the consequences of a mixed electrostatic/constrained modeling for the coordination between the metal and the po
Object Oriented Toolbox for Modelling and Simulation of Dynamic Systems
DEFF Research Database (Denmark)
Thomsen, Per Grove; Poulsen, Mikael Zebbelin; Wagner, Falko Jens;
1999-01-01
Design and Implementation of a simulation toolbox based on Object Oriented modelling Techniques.Experimental implementation in C++ using the Godess ODE-solution platform.......Design and Implementation of a simulation toolbox based on Object Oriented modelling Techniques.Experimental implementation in C++ using the Godess ODE-solution platform....
Application of computer simulated persons in indoor environmental modeling
DEFF Research Database (Denmark)
Topp, C.; Nielsen, P. V.; Sørensen, Dan Nørtoft
2002-01-01
Computer simulated persons are often applied when the indoor environment is modeled by computational fluid dynamics. The computer simulated persons differ in size, shape, and level of geometrical complexity, ranging from simple box or cylinder shaped heat sources to more humanlike models. Little...
Exploiting Modelling and Simulation in Support of Cyber Defence
Klaver, M.H.A.; Boltjes, B.; Croom-Jonson, S.; Jonat, F.; Çankaya, Y.
2014-01-01
The rapidly evolving environment of Cyber threats against the NATO Alliance has necessitated a renewed focus on the development of Cyber Defence policy and capabilities. The NATO Modelling and Simulation Group is looking for ways to leverage Modelling and Simulation experience in research, analysis
Exploiting Modelling and Simulation in Support of Cyber Defence
Klaver, M.H.A.; Boltjes, B.; Croom-Jonson, S.; Jonat, F.; Çankaya, Y.
2014-01-01
The rapidly evolving environment of Cyber threats against the NATO Alliance has necessitated a renewed focus on the development of Cyber Defence policy and capabilities. The NATO Modelling and Simulation Group is looking for ways to leverage Modelling and Simulation experience in research, analysis
Combat Simulation Modeling in Naval Special Warfare Mission Planning.
1995-12-01
This thesis explores the potential role of combat simulation modeling in the Naval Special Warfare mission planning cycle. It discusses methods for...at the tactical level. The thesis concludes by discussing additional applications of combat simulation modeling within the Naval Special Warfare community and makes recommendations for its effective and efficient implementation.
Flow Through a Laboratory Sediment Sample by Computer Simulation Modeling
2006-09-07
Flow through a laboratory sediment sample by computer simulation modeling R.B. Pandeya’b*, Allen H. Reeda, Edward Braithwaitea, Ray Seyfarth0, J.F...through a laboratory sediment sample by computer simulation modeling 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S
Autonomous underwater vehicles modeling, control design and simulation
Wadoo, Sabiha
2010-01-01
Underwater vehicles present some difficult and very particular control system design problems. These are often the result of nonlinear dynamics and uncertain models, as well as the presence of sometimes unforeseeable environmental disturbances that are difficult to measure or estimate. Autonomous Underwater Vehicles: Modeling, Control Design, and Simulation outlines a novel approach to help readers develop models to simulate feedback controllers for motion planning and design. The book combines useful information on both kinematic and dynamic nonlinear feedback control models, providing simula
Adaptive Simulated Annealing Based Protein Loop Modeling of Neurotoxins
Institute of Scientific and Technical Information of China (English)
陈杰; 黄丽娜; 彭志红
2003-01-01
A loop modeling method, adaptive simulated annealing, for ab initio prediction of protein loop structures, as an optimization problem of searching the global minimum of a given energy function, is proposed. An interface-friendly toolbox-LoopModeller in Windows and Linux systems, VC++ and OpenGL environments is developed for analysis and visualization. Simulation results of three short-chain neurotoxins modeled by LoopModeller show that the method proposed is fast and efficient.
T=S Model to Simulate Regional Economic Development
Institute of Scientific and Technical Information of China (English)
WangQing; ChenGuo-jie; ZhangYu; ChenYong
2003-01-01
This paper proposes a mechanism theory on regional development by using a modified Logistic model. It reveals regional evolution is an integration of fluctuation in temporal dimension and disparity in spatial dimension. T=S model is established by using Logistic model to simulate the growth of per capita GDP in China from 1990 to 1999. The result shows that T=S model accurately simulates the tracks of economic growth.
T=S Model to Simulate Regional Economic Development
Institute of Scientific and Technical Information of China (English)
Wang Qing; Chen Guo-jie; Zhang Yu; Chen Yong
2003-01-01
This paper proposes a mechanism theory on regional development by using a modified Logistic model. It reveals regional evolution is an integration of fluctuation in temporal dimcnsion and disparity in spatial dimension. T = S model is established by using Logistic model to simulate the growth of per capita GDP in China from 1990 to 1999. The result shows that T= S model accurately simulates the tracks of economic growth.
Photodiode Circuit Macro-model for SPICE Simulation
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
An accurate photodiode circuit macro-model is proposed for SPICE simulation. The definition and implementation of the macro-model is based on carrier stationary continuity equation. In this macro-model, the photodiode is a device of three pins, one for light intensity input and the other two for photocurrent output, which represent the relationship between photocurrent and incident light. The validity of the proposed macro-model is demonstrated with its PSPICE simulation result compared with reported experimental data.
Dynamic wind turbine models in power system simulation tool
DEFF Research Database (Denmark)
Hansen, A.; Jauch, Clemens; Soerensen, P.
The present report describes the dynamic wind turbine models implemented in the power system simulation tool DIgSILENT. The developed models are a part of the results of a national research project, whose overall objective is to create a model database in different simulation tools. The report...... provides a description of the wind turbine modelling, both at a component level and at a system level....
A novel computer simulation for modeling grain growth
Energy Technology Data Exchange (ETDEWEB)
Chen, L.Q. (Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering)
1995-01-01
In this paper, the author proposes a new computer simulation model for investigating grain growth kinetics, born from the recent work on the domain growth kinetics of a quenched system with many non-conserved order parameters. A key new feature of this model for studying grain growth is that the grain boundaries are diffuse, as opposed to previous meanfield and statistical theories and Monte-Carlo simulations which assumed that grain boundaries were sharp. Unlike the Monte-Carlo simulations in which grain boundaries are made up of kinks, grain boundaries in the continuum model are smooth. Below, he describes this model in detail, give prescriptions for computer simulation, and then present computer simulation results on a two-dimensional model system.
Catalog of Wargaming and Military Simulation Models
1989-09-01
Generic Missile Model . MODEL TYPE: Analysis. PROPONENT: WftDC, Avionics Laboratory...requirements. Users: Primarily WRDC/AAWA. Comments: N/A. G-4 TITLE: GFGMMLCM - GEneric Missile Model with Tracking Loops and Counter-Measure SMODEI TYPE...Structure Trade-Off Analysis Model ............ F-31 G2WS - G2 Workstation ................. ..................... C-I GEUI - Generic Missile Model ................................
Hybrid Modeling and Simulation of Automotive Supply Chain Network
Directory of Open Access Journals (Sweden)
Wen Wang
2013-07-01
Full Text Available According to the operation of automotive supply chain and the features of various simulation methods, we create and simulate a automotive supply chain network model with the core enterprise of two vehicle manufacturers, consisting of several parts suppliers, vehicle distributors and logistics service providers. On this basis of a conceptual model including the establishment of enterprise layer, business layer and operation layer, we establish a detailed model of the network system according to the network structure of automotive supply chain, the operation process and the internal business process of core enterprises; then we use System Dynamics (SD, Discrete Event Simulation (DES and Agent Based Modeling (ABM to describe the operating state of each node in the network model. We execute and analyze the simulation model of the whole network system described by Anylogic, using the results of the distributors’ inventory, inventory cost and customer’s satisfaction to prove the effectiveness of the model.
SDG-based Model Validation in Chemical Process Simulation
Institute of Scientific and Technical Information of China (English)
张贝克; 许欣; 马昕; 吴重光
2013-01-01
Signed direct graph (SDG) theory provides algorithms and methods that can be applied directly to chemical process modeling and analysis to validate simulation models, and is a basis for the development of a soft-ware environment that can automate the validation activity. This paper is concentrated on the pretreatment of the model validation. We use the validation scenarios and standard sequences generated by well-established SDG model to validate the trends fitted from the simulation model. The results are helpful to find potential problems, as-sess possible bugs in the simulation model and solve the problem effectively. A case study on a simulation model of boiler is presented to demonstrate the effectiveness of this method.
A Simulation and Modeling Framework for Space Situational Awareness
Energy Technology Data Exchange (ETDEWEB)
Olivier, S S
2008-09-15
This paper describes the development and initial demonstration of a new, integrated modeling and simulation framework, encompassing the space situational awareness enterprise, for quantitatively assessing the benefit of specific sensor systems, technologies and data analysis techniques. The framework is based on a flexible, scalable architecture to enable efficient, physics-based simulation of the current SSA enterprise, and to accommodate future advancements in SSA systems. In particular, the code is designed to take advantage of massively parallel computer systems available, for example, at Lawrence Livermore National Laboratory. The details of the modeling and simulation framework are described, including hydrodynamic models of satellite intercept and debris generation, orbital propagation algorithms, radar cross section calculations, optical brightness calculations, generic radar system models, generic optical system models, specific Space Surveillance Network models, object detection algorithms, orbit determination algorithms, and visualization tools. The use of this integrated simulation and modeling framework on a specific scenario involving space debris is demonstrated.
Directory of Open Access Journals (Sweden)
S. Gómez
2005-01-01
Full Text Available Se presenta un simulador de sombras vectoriales por radiación solar sobre objetos tridimensionales, SSV3D, una herramienta de computación gráfica desarrollada sobre la plataforma tridimensional del AUTOCAD 2004. El software simula vectorialmente la radiación solar directa, calculando y trazando los contornos de sombra sobre los planos iluminados del modelo 3D evaluado. En el desarrollo de la herramienta se comprobaron los resultados analíticos mediante su comparación con los obtenidos en las fórmulas de una hoja de cálculo, y de los resultados gráficos mediante comparación con las sombras arrojadas por simulación con un heliodón de tecnología francesa y por el Render de AUTOCAD. El simulador SSV3D respondió satisfactoriamente a las necesidades de estudio de sistemas de protección solar en investigaciones desarrolladas anteriormente.SSV3D is presented as a graphic computer tool developed on the three-dimensional platform of AUTOCAD 2004, which simulates direct solar radiation by measuring and vectorial tracing of shadow outlines on illuminated plans of the 3D model evaluated. The analytical results of this tool were tested during its' development by comparing its' results with those obtained in the formula of a calculus sheet, and graphic results were checked comparing these to the shadows obtained by simulation using physical models in a heliodon (French technology and by the Render of AUTOCAD. The SSV3D simulator responded satisfactorily to the requirements for the study of solar protection systems which had been determined in previous research.
A Jitter Less VCO Model in PLL for EMTP Simulation
Funaki, Tsuyoshi; Hikihara, Takashi
PLL is used to synchronize the phase of an inverter AC output with that of an utility AC. The dynamic PLL behavior must be accurately simulated for it governs the control performance of an inverter. The VCO part of a PLL conventionally consists of an integrator, which is reset at the instant when it exceeds 2π. A numerical simulation, such as an EMTP simulation, with a fixed time step calculation cannot detect these accurate reset timings. This inconsistency in reset timing induces a phase jitter. The phase error, due to jitter, becomes a severe problem when a large time step is employed to simulate long period phenomena, and the inverter is modeled by the state-space averaging method. This paper proposes a jitter less VCO model for EMTP simulation. The phase jitter of the proposed VCO model is completely suppressed, regardless of the time step length. The improvements are confirmed through EMTP simulations.
Simulation modeling on the growth of firm's safety management capability
Institute of Scientific and Technical Information of China (English)
LIU Tie-zhong; LI Zhi-xiang
2008-01-01
Aiming to the deficiency of safety management measure, established simulation model about firm's safety management capability(FSMC) based on organizational learning theory. The system dynamics(SD) method was used, in which level and rate system, variable equation and system structure flow diagram was concluded. Simulation model was verified from two aspects: first, model's sensitivity to variable was tested from the gross of safety investment and the proportion of safety investment; second, variables dependency was checked up from the correlative variable of FSMC and organizational learning. The feasibility of simulation model is verified though these processes.
Simplified Model of Brushless Synchronous Generator for Real Time Simulation
Lopez, M D; Rebollo, E; Blanquez, F R
2015-01-01
This paper presents a simplified model of brushless synchronous machine for saving hardware resources in a real time simulation system. Firstly, a brushless excitation system model is described. Thereafter, the simplified transfer function of an AC exciter and rotating diodes of the brushless excitation system is estimated. Finally, the complete system is simulated, comparing the main generator's voltage with both detailed and simplified excitation systems in several scenarios. These results show the accuracy of the simplified model against the detailed simulation model, resulting on an important hardware resources savings.
Handbook of Real-World Applications in Modeling and Simulation
Sokolowski, John A
2012-01-01
This handbook provides a thorough explanation of modeling and simulation in the most useful, current, and predominant applied areas, such as transportation, homeland security, medicine, operational research, military science, and business modeling. The authors offer a concise look at the key concepts and techniques of modeling and simulation and then discuss how and why the presented domains have become leading applications. The book begins with an introduction of why modeling and simulation is a reliable analysis assessment tool for complex syste
Optical modeling and simulation of thin-film photovoltaic devices
Krc, Janez
2013-01-01
In wafer-based and thin-film photovoltaic (PV) devices, the management of light is a crucial aspect of optimization since trapping sunlight in active parts of PV devices is essential for efficient energy conversions. Optical modeling and simulation enable efficient analysis and optimization of the optical situation in optoelectronic and PV devices. Optical Modeling and Simulation of Thin-Film Photovoltaic Devices provides readers with a thorough guide to performing optical modeling and simulations of thin-film solar cells and PV modules. It offers insight on examples of existing optical models
A study for production simulation model generation system based on data model at a shipyard
Directory of Open Access Journals (Sweden)
Myung-Gi Back
2016-09-01
Full Text Available Simulation technology is a type of shipbuilding product lifecycle management solution used to support production planning or decision-making. Normally, most shipbuilding processes are consisted of job shop production, and the modeling and simulation require professional skills and experience on shipbuilding. For these reasons, many shipbuilding companies have difficulties adapting simulation systems, regardless of the necessity for the technology. In this paper, the data model for shipyard production simulation model generation was defined by analyzing the iterative simulation modeling procedure. The shipyard production simulation data model defined in this study contains the information necessary for the conventional simulation modeling procedure and can serve as a basis for simulation model generation. The efficacy of the developed system was validated by applying it to the simulation model generation of the panel block production line. By implementing the initial simulation model generation process, which was performed in the past with a simulation modeler, the proposed system substantially reduced the modeling time. In addition, by reducing the difficulties posed by different modeler-dependent generation methods, the proposed system makes the standardization of the simulation model quality possible.
Energy Technology Data Exchange (ETDEWEB)
NONE
2005-02-15
In connection with the ERP project 'Dynamic modelling of staged gasification processes' a gasification simulator has been constructed. The simulator consists of: a mathematical model of the gasification process developed at Technical University of Denmark, a user interface programme, IGSS, and a communication interface between the two programmes. (BA)
Probabilistic Based Modeling and Simulation Assessment
2010-06-01
but with the head and neck replaced with a high fidelity cervical spine and head model. The occupant models were used to determine the effects of...fidelity cervical spine and head model... vertebrae , including the disks, ligaments and musculature, Figure 6. In total there are 57837 elements with 63713 nodes. A full description of the model
Model and simulation of Krause model in dynamic open network
Zhu, Meixia; Xie, Guangqiang
2017-08-01
The construction of the concept of evolution is an effective way to reveal the formation of group consensus. This study is based on the modeling paradigm of the HK model (Hegsekmann-Krause). This paper analyzes the evolution of multi - agent opinion in dynamic open networks with member mobility. The results of the simulation show that when the number of agents is constant, the interval distribution of the initial distribution will affect the number of the final view, The greater the distribution of opinions, the more the number of views formed eventually; The trust threshold has a decisive effect on the number of views, and there is a negative correlation between the trust threshold and the number of opinions clusters. The higher the connectivity of the initial activity group, the more easily the subjective opinion in the evolution of opinion to achieve rapid convergence. The more open the network is more conducive to the unity of view, increase and reduce the number of agents will not affect the consistency of the group effect, but not conducive to stability.
Modeling and simulation of membrane process
Staszak, Maciej
2017-06-01
The article presents the different approaches to polymer membrane mathematical modeling. Traditional models based on experimental physicochemical correlations and balance models are presented in the first part. Quantum and molecular mechanics models are presented as they are more popular for polymer membranes in fuel cells. The initial part is enclosed by neural network models which found their use for different types of processes in polymer membranes. The second part is devoted to models of fluid dynamics. The computational fluid dynamics technique can be divided into solving of Navier-Stokes equations and into Boltzmann lattice models. Both approaches are presented focusing on membrane processes.
Application of simulation modeling to lipid peroxidation processes.
Tappel, A L; Tappel, A A; Fraga, C G
1989-01-01
A quantitative simulation model was developed that utilized present knowledge of lipid peroxidation in biological systems. The simulation model incorporated the following features: peroxidizability of polyunsaturated lipids, activation of inducers and their initiation of lipid peroxidation, concurrent autoxidation, inhibition of lipid peroxidation by vitamin E, reduction of some of the hydroperoxides by glutathione peroxidase, and formation of thiobarbituric acid-reactive substances. Simulation calculations were done using a computer spreadsheet program. When the simulation program was applied to tissue slice and microsomal peroxidizing systems, the results of the stimulation were in agreement with the experimental data.
A View on Future Building System Modeling and Simulation
Energy Technology Data Exchange (ETDEWEB)
Wetter, Michael
2011-04-01
This chapter presents what a future environment for building system modeling and simulation may look like. As buildings continue to require increased performance and better comfort, their energy and control systems are becoming more integrated and complex. We therefore focus in this chapter on the modeling, simulation and analysis of building energy and control systems. Such systems can be classified as heterogeneous systems because they involve multiple domains, such as thermodynamics, fluid dynamics, heat and mass transfer, electrical systems, control systems and communication systems. Also, they typically involve multiple temporal and spatial scales, and their evolution can be described by coupled differential equations, discrete equations and events. Modeling and simulating such systems requires a higher level of abstraction and modularisation to manage the increased complexity compared to what is used in today's building simulation programs. Therefore, the trend towards more integrated building systems is likely to be a driving force for changing the status quo of today's building simulation programs. Thischapter discusses evolving modeling requirements and outlines a path toward a future environment for modeling and simulation of heterogeneous building systems.A range of topics that would require many additional pages of discussion has been omitted. Examples include computational fluid dynamics for air and particle flow in and around buildings, people movement, daylight simulation, uncertainty propagation and optimisation methods for building design and controls. For different discussions and perspectives on the future of building modeling and simulation, we refer to Sahlin (2000), Augenbroe (2001) and Malkawi and Augenbroe (2004).
Reducing outpatient waiting time: a simulation modeling approach.
Aeenparast, Afsoon; Tabibi, Seyed Jamaleddin; Shahanaghi, Kamran; Aryanejhad, Mir Bahador
2013-09-01
The objective of this study was to provide a model for reducing outpatient waiting time by using simulation. A simulation model was constructed by using the data of arrival time, service time and flow of 357 patients referred to orthopedic clinic of a general teaching hospital in Tehran. The simulation model was validated before constructing different scenarios. In this study 10 scenarios were presented for reducing outpatient waiting time. Patients waiting time was divided into three levels regarding their physicians. These waiting times for all scenarios were computed by simulation model. According to the final scores the 9th scenario was selected as the best way for reducing outpatient's waiting time. Using the simulation as a decision making tool helps us to decide how we can reduce outpatient's waiting time. Comparison of outputs of this scenario and the based- case scenario in simulation model shows that combining physician's work time changing with patient's admission time changing (scenario 9) would reduce patient waiting time about 73.09%. Due to dynamic and complex nature of healthcare systems, the application of simulation for the planning, modeling and analysis of these systems has lagged behind traditional manufacturing practices. Rapid growth in health care system expenditures, technology and competition has increased the complexity of health care systems. Simulation is a useful tool for decision making in complex and probable systems.
Calibration of the simulation model of the VINCY cyclotron magnet
Directory of Open Access Journals (Sweden)
Ćirković Saša
2002-01-01
Full Text Available The MERMAID program will be used to isochronise the nominal magnetic field of the VINCY Cyclotron. This program simulates the response, i. e. calculates the magnetic field, of a previously defined model of a magnet. The accuracy of 3D field calculation depends on the density of the grid points in the simulation model grid. The size of the VINCY Cyclotron and the maximum number of grid points in the XY plane limited by MERMAID define the maximumobtainable accuracy of field calculations. Comparisons of the field simulated with maximum obtainable accuracy with the magnetic field measured in the first phase of the VINCY Cyclotron magnetic field measurements campaign has shown that the difference between these two fields is not as small as required. Further decrease of the difference between these fields is obtained by the simulation model calibration, i. e. by adjusting the current through the main coils in the simulation model.
Calibration of the simulation model of the Vincy cyclotron magnet
Cirkovic, S; Vorozhtsov, A S; Vorozhtsov, S B
2002-01-01
The MERMAID program will be used to isochronise the nominal magnetic field of the VINCY Cyclotron. This program simulates the response, i. e. calculates the magnetic field, of a previously defined model of a magnet. The accuracy of 3D field calculation depends on the density of the grid points in the simulation model grid. The size of the VINCY Cyclotron and the maximum number of grid points in the XY plane limited by MERMAID define the maximum obtainable accuracy of field calculations. Comparisons of the field simulated with maximum obtainable accuracy with the magnetic field measured in the first phase of the VINCY Cyclotron magnetic field measurements campaign has shown that the difference between these two fields is not as small as required. Further decrease of the difference between these fields is obtained by the simulation model calibration, i. e. by adjusting the current through the main coils in the simulation model.
MODELING OF HIGH STORAGE SHEET DEPOT WITH PLANT SIMULATION
Directory of Open Access Journals (Sweden)
Andrzej Jardzioch
2013-03-01
Full Text Available Manufacturing processes are becoming increasingly automated. Introduction of innovative solutions often necessitate processing very large number of signals from various devices. Correctness tests of the components configuration becomes a compiled operation requiring vast expenditure of time and knowledge. The models may be a mathematical reflection of the actual object. Many actions can be computer-assisted to varying degree. One example is construction of simulation models. These can also be simulation models developed in advanced software. The stages of creating a model may be purely random. This paper aims at a closer analysis of the simulation model based on the high storage sheet depot modeling using Plant Simulation software. The results of analysis can be used for optimization, but this stage is a separate issue.
A framework for the calibration of social simulation models
Ciampaglia, Giovanni Luca
2013-01-01
Simulation with agent-based models is increasingly used in the study of complex socio-technical systems and in social simulation in general. This paradigm offers a number of attractive features, namely the possibility of modeling emergent phenomena within large populations. As a consequence, often the quantity in need of calibration may be a distribution over the population whose relation with the parameters of the model is analytically intractable. Nevertheless, we can simulate. In this paper we present a simulation-based framework for the calibration of agent-based models with distributional output based on indirect inference. We illustrate our method step by step on a model of norm emergence in an online community of peer production, using data from three large Wikipedia communities. Model fit and diagnostics are discussed.
HUMAN RELIABILITY ANALYSIS FOR COMPUTERIZED PROCEDURES
Energy Technology Data Exchange (ETDEWEB)
Ronald L. Boring; David I. Gertman; Katya Le Blanc
2011-09-01
This paper provides a characterization of human reliability analysis (HRA) issues for computerized procedures in nuclear power plant control rooms. It is beyond the scope of this paper to propose a new HRA approach or to recommend specific methods or refinements to those methods. Rather, this paper provides a review of HRA as applied to traditional paper-based procedures, followed by a discussion of what specific factors should additionally be considered in HRAs for computerized procedures. Performance shaping factors and failure modes unique to computerized procedures are highlighted. Since there is no definitive guide to HRA for paper-based procedures, this paper also serves to clarify the existing guidance on paper-based procedures before delving into the unique aspects of computerized procedures.
Computerizing marine biota: a rational approach
Digital Repository Service at National Institute of Oceanography (India)
Chavan, V.S.; Chandramohan, D.; Parulekar, A.H.
Data on marine biota while being extensive are also patchy and scattered; thus making retrieval and dissemination of information time consuming. This emphasise the need for computerizing information on marine biota with the objective to collate...
NATO Modelling and Simulation Standards Profile
Huiskamp, W.; Igarza, J.L.; Voiculet, A.
2012-01-01
Open and common standards are essential enablers for simulation interoperability and re-use. This includes: Technical architecture standards - e.g. HLA - the High Level Architecture, Data interchange standards - e.g. SEDRIS - Synthetic Environment Data Representation and Interchange
Motion perception modelling in flight simulation
Groen, E.L.; Hosman, R.J.A.W.; Bos, J.E.; Dominicus, J.W.
2004-01-01
Motion cueing algorithms are indispensable to transform aircraft motions into simulator motions. Usually, such algorithms apply to the whole flight envelope. Since a motion base should stay within its six degrees of freedom workspace, the parameter settings necessarily involve concessions, which may
Cognitive model supported tactical training simulation
Doesburg, W.A. van; Bosch, K. van den
2005-01-01
Simulation-based tactical training can be made more effective by using cognitive software agents to play key roles (e.g. team mate, adversaries, instructor). Due to the dynamic and complex nature of military tactics, it is hard to create agents that behave realistically and support the training lead
System Simulation Modeling: A Case Study Illustration of the Model Development Life Cycle
Janice K. Wiedenbeck; D. Earl Kline
1994-01-01
Systems simulation modeling techniques offer a method of representing the individual elements of a manufacturing system and their interactions. By developing and experimenting with simulation models, one can obtain a better understanding of the overall physical system. Forest products industries are beginning to understand the importance of simulation modeling to help...
Plant growth simulation for landscape scale hydrologic modeling
Landscape scale hydrologic models can be improved by incorporating realistic, process-oriented plant models for simulating crops, grasses, and woody species. The objective of this project was to present some approaches for plant modeling applicable to hydrologic models like SWAT that can affect the...
A transient model to simulate HTPEM fuel cell impedance spectra
DEFF Research Database (Denmark)
Vang, Jakob Rabjerg; Andreasen, Søren Juhl; Kær, Søren Knudsen
2012-01-01
This paper presents a spatially resolved transient fuel cell model applied to the simulation of high temperature PEM fuel cell impedance spectra. The model is developed using a 2D finite volume method approach. The model is resolved along the channel and across the membrane. The model considers...
Discrete event simulation: Modeling simultaneous complications and outcomes
Quik, E.H.; Feenstra, T.L.; Krabbe, P.F.M.
2012-01-01
OBJECTIVES: To present an effective and elegant model approach to deal with specific characteristics of complex modeling. METHODS: A discrete event simulation (DES) model with multiple complications and multiple outcomes that each can occur simultaneously was developed. In this DES model parameters,
Geometry model construction in infrared image theory simulation of buildings
Institute of Scientific and Technical Information of China (English)
谢鸣; 李玉秀; 徐辉; 谈和平
2004-01-01
Geometric model construction is the basis of infrared image theory simulation. Taking the construction of the geometric model of one building in Harbin as an example, this paper analyzes the theoretical groundings of simplification and principles of geometric model construction of buildings. It then discusses some particular treatment methods in calculating the radiation transfer coefficient in geometric model construction using the Monte Carlo Method.
DEFF Research Database (Denmark)
Olsen, Martin; Troldborg, Lars; Boegh, Eva
2008-01-01
The consequences of using simulated discharge from a conventional hydrological model as input in stream physical habitat modelling was investigated using output from the Danish national hydrological model and a physical habitat model of three small streams. It was found that low flow simulation...... errors could have large impact on simulation of physical habitat conditions. If these two models are to be used to assess groundwater abstraction impact on physical habitat conditions the hydrological model should be tuned to the purpose...
DEFF Research Database (Denmark)
Olsen, Martin; Troldborg, Lars; Boegh, Eva;
2008-01-01
The consequences of using simulated discharge from a conventional hydrological model as input in stream physical habitat modelling was investigated using output from the Danish national hydrological model and a physical habitat model of three small streams. It was found that low flow simulation...... errors could have large impact on simulation of physical habitat conditions. If these two models are to be used to assess groundwater abstraction impact on physical habitat conditions the hydrological model should be tuned to the purpose...
Air Gun Launch Simulation Modeling and Finite Element Model Sensitivity Analysis
2006-01-01
Air Gun Launch Simulation Modeling and Finite Element Model Sensitivity Analysis by Mostafiz R. Chowdhury and Ala Tabiei ARL-TR-3703...Adelphi, MD 20783-1145 ARL-TR-3703 January 2006 Air Gun Launch Simulation Modeling and Finite Element Model Sensitivity Analysis...GRANT NUMBER 4. TITLE AND SUBTITLE Air Gun Launch Simulation Modeling and Finite Element Model Sensitivity Analysis 5c. PROGRAM
Optimal item pool design for computerized adaptive tests with polytomous items using GPCM
Directory of Open Access Journals (Sweden)
Xuechun Zhou
2014-09-01
Full Text Available Computerized adaptive testing (CAT is a testing procedure with advantages in improving measurement precision and increasing test efficiency. An item pool with optimal characteristics is the foundation for a CAT program to achieve those desirable psychometric features. This study proposed a method to design an optimal item pool for tests with polytomous items using the generalized partial credit model (G-PCM. It extended a method for approximating optimality with polytomous items being described succinctly for the purpose of pool design. Optimal item pools were generated using CAT simulations with and without practical constraints of content balancing and item exposure control. The performances of the item pools were evaluated against an operational item pool. The results indicated that the item pools designed with stratification based on discrimination parameters performed well with an efficient use of the less discriminative items within the target accuracy levels. The implications for developing item pools are also discussed.
Computerization of Hungarian reforestation manual with machine learning methods
Czimber, Kornél; Gálos, Borbála; Mátyás, Csaba; Bidló, András; Gribovszki, Zoltán
2017-04-01
Hungarian forests are highly sensitive to the changing climate, especially to the available precipitation amount. Over the past two decades several drought damages were observed for tree species which are in the lower xeric limit of their distribution. From year to year these affected forest stands become more difficult to reforest with the same native species because these are not able to adapt to the increasing probability of droughts. The climate related parameter set of the Hungarian forest stand database needs updates. Air humidity that was formerly used to define the forest climate zones is not measured anymore and its value based on climate model outputs is highly uncertain. The aim was to develop a novel computerized and objective method to describe the species-specific climate conditions that is essential for survival, growth and optimal production of the forest ecosystems. The method is expected to project the species spatial distribution until 2100 on the basis of regional climate model simulations. Until now, Hungarian forest managers have been using a carefully edited spreadsheet for reforestation purposes. Applying binding regulations this spreadsheet prescribes the stand-forming and admixed tree species and their expected growth rate for each forest site types. We are going to present a new machine learning based method to replace the former spreadsheet. We took into great consideration of various methods, such as maximum likelihood, Bayesian networks, Fuzzy logic. The method calculates distributions, setups classification, which can be validated and modified by experts if necessary. Projected climate change conditions makes necessary to include into this system an additional climate zone that does not exist in our region now, as well as new options for potential tree species. In addition to or instead of the existing ones, the influence of further limiting parameters (climatic extremes, soil water retention) are also investigated. Results will be
Heterogeneous Speed Profiles in Discrete Models for Pedestrian Simulation
Bandini, Stefania; Crociani, Luca; Vizzari, Giuseppe
2014-01-01
Discrete pedestrian simulation models are viable alternatives to particle based approaches based on a continuous spatial representation. The effects of discretisation, however, also imply some difficulties in modelling certain phenomena that can be observed in reality. This paper focuses on the possibility to manage heterogeneity in the walking speed of the simulated population of pedestrians by modifying an existing multi-agent model extending the floor field approach. Whereas some discrete ...
Verilog-A modeling of SPAD for circuit simulations
Yang, Hong-jiao; Jin, Xiang-liang; Zhou, Xiao-ya; Chen, Chang-ping; Luo, Jun
2013-08-01
A behavior mode for simulating single-photon avalanche diodes is presented. The model is developed using Verilog-A description language. The derived model is able to describe the static, the dynamic behavior, the triggering, the self-sustaining and the self-quenching processes, and it also correctly characterizes the reverse current-voltage curve. Simulation results confirmed the validity of the proposed model.
Integrated simulation and modeling capability for alternate magnetic fusion concepts
Energy Technology Data Exchange (ETDEWEB)
Cohen, B. I.; Hooper, E.B.; Jarboe, T. R.; LoDestro, L. L.; Pearlstein, L. D.; Prager, S. C.; Sarff, J. S.
1998-11-03
This document summarizes a strategic study addressing the development of a comprehensive modeling and simulation capability for magnetic fusion experiments with particular emphasis on devices that are alternatives to the mainline tokamak device. A code development project in this area supports two defined strategic thrust areas in the Magnetic Fusion Energy Program: (1) comprehensive simulation and modeling of magnetic fusion experiments and (2) development, operation, and modeling of magnetic fusion alternate- concept experiment
Modified Head Shake Computerized Dynamic Posturography
2009-12-01
form of dizziness (in- cluding complaints of lightheadedness, vertigo , or un- steadiness) lasting longer than 1 hr or recurring for greater than 1...noted limitations. Method: Forty participants ranging in age from 20 to 79 years with no history of dizziness completed Conditions 2 and 5 of the SOT...shake, Sensory Organization Test, computerized dynamic posturography, dizziness Computerized dynamic posturography (CDP) is anassessment of an
Methodology for characterizing modeling and discretization uncertainties in computational simulation
Energy Technology Data Exchange (ETDEWEB)
ALVIN,KENNETH F.; OBERKAMPF,WILLIAM L.; RUTHERFORD,BRIAN M.; DIEGERT,KATHLEEN V.
2000-03-01
This research effort focuses on methodology for quantifying the effects of model uncertainty and discretization error on computational modeling and simulation. The work is directed towards developing methodologies which treat model form assumptions within an overall framework for uncertainty quantification, for the purpose of developing estimates of total prediction uncertainty. The present effort consists of work in three areas: framework development for sources of uncertainty and error in the modeling and simulation process which impact model structure; model uncertainty assessment and propagation through Bayesian inference methods; and discretization error estimation within the context of non-deterministic analysis.
Four Order Electrostatic Discharge Circuit Model and its Simulation
Directory of Open Access Journals (Sweden)
Xiaodong Wang
2012-12-01
Full Text Available According to the international electrotechnical commission issued IEC61000-4-2 test standard, through the electrostatic discharge current waveform characteristics analysis and numerical experiment method, and construct a new ESD current expression. Using Laplasse transform, established the ESD system mathematical model. According to the mathematical model, construction of passive four order ESD system circuit model and active four order ESD system circuit model, and simulation. The simulation results meet the IEC61000-4-2 standard, and verify the consistency of the ESD current expression, the mathematical model and the circuit model.
Computerization of Mental Health Integration complexity scores at Intermountain Healthcare.
Oniki, Thomas A; Rodrigues, Drayton; Rahman, Noman; Patur, Saritha; Briot, Pascal; Taylor, David P; Wilcox, Adam B; Reiss-Brennan, Brenda; Cannon, Wayne H
2014-01-01
Intermountain Healthcare's Mental Health Integration (MHI) Care Process Model (CPM) contains formal scoring criteria for assessing a patient's mental health complexity as "mild," "medium," or "high" based on patient data. The complexity score attempts to assist Primary Care Physicians in assessing the mental health needs of their patients and what resources will need to be brought to bear. We describe an effort to computerize the scoring. Informatics and MHI personnel collaboratively and iteratively refined the criteria to make them adequately explicit and reflective of MHI objectives. When tested on retrospective data of 540 patients, the clinician agreed with the computer's conclusion in 52.8% of the cases (285/540). We considered the analysis sufficiently successful to begin piloting the computerized score in prospective clinical care. So far in the pilot, clinicians have agreed with the computer in 70.6% of the cases (24/34).
Optimization of Operations Resources via Discrete Event Simulation Modeling
Joshi, B.; Morris, D.; White, N.; Unal, R.
1996-01-01
The resource levels required for operation and support of reusable launch vehicles are typically defined through discrete event simulation modeling. Minimizing these resources constitutes an optimization problem involving discrete variables and simulation. Conventional approaches to solve such optimization problems involving integer valued decision variables are the pattern search and statistical methods. However, in a simulation environment that is characterized by search spaces of unknown topology and stochastic measures, these optimization approaches often prove inadequate. In this paper, we have explored the applicability of genetic algorithms to the simulation domain. Genetic algorithms provide a robust search strategy that does not require continuity and differentiability of the problem domain. The genetic algorithm successfully minimized the operation and support activities for a space vehicle, through a discrete event simulation model. The practical issues associated with simulation optimization, such as stochastic variables and constraints, were also taken into consideration.
Semiempirical model for nanoscale device simulations
DEFF Research Database (Denmark)
Stokbro, Kurt; Petersen, Dan Erik; Smidstrup, Søren;
2010-01-01
We present a semiempirical model for calculating electron transport in atomic-scale devices. The model is an extension of the extended Hückel method with a self-consistent Hartree potential that models the effect of an external bias and corresponding charge rearrangements in the device. It is als...
A universal simulator for ecological models
DEFF Research Database (Denmark)
Holst, Niels
2013-01-01
Software design is an often neglected issue in ecological models, even though bad software design often becomes a hindrance for re-using, sharing and even grasping an ecological model. In this paper, the methodology of agile software design was applied to the domain of ecological models. Thus...
Modeling Physics with Easy Java Simulations
Christian, Wolfgang; Esquembre, Francisco
2007-01-01
Modeling has been shown to correct weaknesses of traditional instruction by engaging students in the design of physical models to describe, explain, and predict phenomena. Although the modeling method can be used without computers, the use of computers allows students to study problems that are difficult and time consuming, to visualize their…
Coastal zone simulations with variational Boussinesq modelling
Adytia, Didit
2012-01-01
The main challenge in deriving a Boussinesq model for water wave is to model accurately the dispersion and nonlinearity of waves. The dispersion is a depth-dependent relation between the wave speed and the wavelength. A Boussinesq-type model can be derived from the so-called variational principle