Computer-generated animation for analysis and design

The development of computer-generated animation techniques was reviewed and some examples of the current state of the art were described. A number of ways in which computer-generated animation can be used were examined in relation to the suitability for the engineering task at hand. The examples described are primarily concerned with attempting to combine two different types of simulation: that of superposition of an engineering design on the surrounding real world, and an evaluation of this simulation both from an engineering design and an aesthetic point of view

Effective simulation techniques for biological systems

In this paper we give an overview of some very recent work on the stochastic simulation of systems involving chemical reactions. In many biological systems (such as genetic regulation and cellular dynamics) there is a mix between small numbers of key regulatory proteins, and medium and large numbers of molecules. In addition, it is important to be able to follow the trajectories of individual molecules by taking proper account of the randomness inherent in such a system. We describe different types of simulation techniques (including the stochastic simulation algorithm, Poisson Runge-Kutta methods and the Balanced Euler method) for treating simulations in the three different reaction regimes: slow, medium and fast. We then review some recent techniques on the treatment of coupled slow and fast reactions for stochastic chemical kinetics and discuss how novel computing implementations can enhance the performance of these simulations

Perspectives on Case-based Multimedia Web Projects in Science

This article discusses the merits of case-based learning in an interactive online environment. Researchers used both qualitative and quantitative research over a 2-year period to examine the learning that occurred in a high school context when students were engaged in a case-based multimedia project. Part of the Case It! project, students played both the role of laboratory technician performing and presenting research as well as professionals using the information in their practice. Students were required to use three types of simulation software developed exclusively for the Case It! project. Results were measured using both pre- and post-tests, artifacts students created such as Web posters, records of Internet conferences, and interviews from both the students and the teacher involved in this project. Researches found the online format of the lesson fostered a higher level of questioning and problem solving skills, as well as extended explanations and discussions of ethics in science. Educational levels: Graduate or professional

A superelement-based method for computing unsteady three-dimensional potential flows in hydraulic turbomachines

A numerical method is presented for the computation of unsteady, three-dimensional potential flows in hydraulic pumps and turbines. The superelement method has been extended in order to eliminate slave degrees of freedom not only from the governing Laplace equation, but also from the Kutta conditions. The resulting superelement formulation is invariant under rotation. Therefore the geometrical symmetry of the flow channels in the rotor can be exploited. This makes the method especially suitable to performing fully coupled computations of the unsteady flow phenomena in both rotor and stator, the so-called rotor-stator interaction. \ud The developed numerical method is used to simulate the unsteady flow in an industrial mixed-flow pump. Two types of simulation are considered: one in which unsteady wakes behind the trailing edges of the rotor blades are taken into account and one in which these are neglected. Results are given that show the importance of unsteady flow phenomena. However, the computed head-capacity curve is hardly influenced by whether or not unsteady wakes are taken into account

Maintaining symmetry of simulated likelihood functions

This paper suggests solutions to two different types of simulation errors related to Quasi-Monte Carlo integration. Likelihood functions which depend on standard deviations of mixed parameters are symmetric in nature. This paper shows that antithetic draws preserve this symmetry and thereby improves precision substantially. Another source of error is that models testing away mixing dimensions must replicate the relevant dimensions of the quasi-random draws in the simulation of the restricted likelihood. These simulation errors are ignored in the standard estimation procedures used today and this paper shows that the result may be substantial estimation- and inference errors within the span of draws typically applied.Quasi-Monte Carlo integration; Antithetic draws; Likelihood Ratio tests; simulated likelihood; panel mixed multinomial logit; Halton draws

Supply Chain Simulation: A Survey

This paper provides a survey of simulation in supply chain management.It reviews four types of simulation, namely spreadsheet simulation, system dynamics, discreteevent simulation, and business games.Which simulation type should be applied, depends on the type of managerial question to be answered by the model.Moreover, this paper summarizes novel sensitivity and robustness analyses.This sensitivity analysis yields a shortlist of the truly important factors in large simulation models with (say) a hundred factors.The robustness analysis optimises the important factors controllable by management, while accounting for the noise created by the important non-controllable, environmental factors.Both analyses are illustrated by a case study involving the simulation of a supply chain in the mobile communications industry in Sweden.In general, simulation is important because it may support the quantification of the benefits resulting from supply chain management.simulation;logistics;performance measurement;risk analysis;uncertainty;bifurcation;supply chain management

An Empirical Assessment Of Three Types Of Simulation Models Used In Developing Decision Support Systems

Visual interactive simulation (VIS) was first developed in the mid-1970s and has been claimed to be a better type of simulation model than traditional simulation for supporting decision making. VIS models which compare two simulated systems using paired-difference statistics have been claimed to be a more powerful decision-support tool than viewing animated simulation model output or steady state statistics. Since simulation is one of the most frequently used techniques in decision support systems (DSS), an examination of which type of simulation model is better for developing DSS is of vital importance. This dissertation focuses on examining and comparing the relative effectiveness and efficiency of three types of simulation models: traditional simulation models, conventional VIS models, and VIS models with paired-systems and paired-difference statistics.;The research was done through a laboratory experiment in which seventy-one second-year Masters\u27 students in Business Administration at the Western Business School participated and were randomly assigned to one of the three experimental groups. Three DSS (one based on a traditional simulation model, one on a conventional VIS model, and one on a VIS model with paired-systems and paired-difference statistics) were developed and each was assigned to one of the three experimental groups. Subjects were asked to solve a production problem presented as a case using the DSS provided.;The results of the experiment indicated that of the three types of DSS, the one based on a VIS model with paired-systems and paired-difference statistics was the most effective and efficient. The DSS based on a conventional VIS model was the second most effective, while the traditional simulation was the least effective. In particular, the DSS based on a VIS model with paired-systems and paired-difference statistics significantly outperformed traditional simulation on all five evaluation criteria defined and used in this study.;This research made three important contributions: first, the work provided management science/operations research (MS/OR) researchers with the first empirical comparison of three different types of simulation-based DSS, and the results of the study provided the first strong empirical case for the use of VIS. Second, the research rigorously tested two claims in the literature by proponents of VIS. Third, the results of this research provided MS/OR practitioners with new insight on the development of simulation-based DSS

Barriers, Challenges, and Supports to the Implementation of Standardized Patients and Simulated Environments by Occupational Therapy Education Programs

A national survey examined the implementation rates, barriers, challenges, and supports to implementation of two types of simulation (standardized patients and simulated environments) by entry-level occupational therapy education programs in the United States. It also sought to identify relationships between program characteristics and implementation of these types of simulation. An online survey inquiring about academic program characteristics and use of simulation was sent to all occupational therapy and occupational therapy assistant programs in the United States in 2017 prior to the implementation of the 2018 Accreditation Council for Occupational Therapy Education Standards and the onset of the COVID-19 Pandemic. Data were analyzed using both statistical and content analysis. There were 97 responses to the survey, with an approximate response rate of 23.8%. Thirty-eight percent of responses used standardized patients and 70% used simulated environments in their didactic coursework. Programs at private institutions were more likely to use standardized patients than programs at public institutions (Cramer’s V=0.229; p=0.024). Funding was the most cited support, challenge, and barrier to the use of standardized patients. Physical space was the most cited support and challenge for the use of simulated environments, with funding as the most cited barrier. Study results indicate that adequate funding, space, and potentially other resources are needed for successful implementation of these types of simulation. Future research should further study the barriers and supports to implementation of simulation by occupational therapy academic programs as well as further examination of implementation rates