The thesis describes a realization of distributed experimental frame concepts in DEVS-SCHEME, an object-oriented simulation environment. Also discussed, are the design and implementation issues concerning the attachments of frame components to a model in a given model structure. The algorithm for the attachments is derived to set up the model composition and model couplings when needed. An example of a simplified computer system which consists of a CPU, and a memory management (MGMT), is presented to demonstrate how such a system is observed and experimented with under centralized and decentralized experimental frames. A graphical interactive interface is provided to facilitate the attachments of frame components to models. The simulation shows that the theory regarding decentralized experimental frames is correct and feasible. Some prospective research topics and future study activities are also brought up.

As the complexity of very-large-scale-integrated-circuits (VLSI) soars, the complexity of verifying them increases even faster. Design verification becomes the biggest bottleneck in VLSI design, consuming around 70% of the effort and time in a typical design cycle. The problem is even more severe as the system-on-chip (SoC) design paradigm is gaining popularity. Unfortunately, the development in verification techniques has not kept up with the growth of the design capability, and is being left further behind in the SoC era. In recent years, a new generation of hardware-modelling-languages alongside the best practices to use them have emerged and evolved in an attempt to productively build an intelligent stimulationobservation environment referred to as the test-bench. Ironically, as test-benches are becoming more powerful and sophisticated under these best practices known as verification methodologies, the overall verification approaches today are still officially described as ad hoc and experimental and are in great need of a methodological breakthrough. Our research was carried out to seek the desirable methodological breakthrough, and this thesis presents the research outcome: a novel and holistic methodology that brings an opportunity to address the SoC verification problems. Furthermore, our methodology is a solution completely independent of the underlying simulation technologies; therefore, it could extend its applicability into future VLSI designs. Our methodology presents two ideas. (a) We propose that system-level verification should resort to the SoC-native languages rather than the test-bench construction languages; the software native to the SoC should take more critical responsibilities than the test-benches. (b) We challenge the fundamental assumption that “objects-under-test” and “tests” are distinct entities; instead, they should be understood as one type of entities – the interactions; interactions, together with the interference between interactions, i.e., the parallelism and resource-competitions, should be treated as the focus in system-level verification. The above two ideas, namely, software-centric verification and interaction-oriented verification have yielded practical techniques. This thesis elaborates on these techniques, including the transfer-resource-graph based test-generation method targeting the parallelism, the coverage measures of the concurrency completeness using Petri-nets, the automation of the test-programs which can execute smartly in an event-driven manner, and a software observation mechanism that gives insights into the system-level behaviours. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1363926 / Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2009

Virtual Reality (VR) simulators have become popular because of two distinctive merits. One is the capability to transfer data and information to users in an intuitive way by means of 3-D high-quality graphics output and real input devices. The other is the capability to represent physical systems in mathematical models so that meaningful responses of the systems can be predicted. Previous efforts in VR excavating machine simulator development, however, showed a lack of balance between the fidelity of the model of the physics and the visual representation of the simulated equipment. In order to ensure that a VR construction excavator simulator provides convincing operating results to users, the focus of simulator development needs to be shifted to interaction of physically valid soil and the excavator machine. This research aims to contribute to the development of a VR construction excavator simulator system by proposing a mathematical model of excavator digging and a calculation methodology. The mathematical model of excavator digging provides physically meaningful soil-bucket interaction information to a simulator. The calculation methodology provides systematic and efficient computation methods to ensure the seamless integration of the excavator digging model with a VR simulator system as well as adequate system speed. As a result, the simulator is realized as an engineering process tool equipped with real-time interactivity. / Ph. D.

The continual growth of computing power in small devices has motivated the development of novel approaches to optimizing operational systems efficiently and effectively. These optimization problems are often so complex that solving them analytically may be difficult, if not prohibited. One method for solving such problems is to use online simulation. However, challenges in using online simulation include the issues of responsiveness (e.g., because of communication delays), scalability, and failure resistance. To tackle these issues, this study proposes embedding online simulations into a network of sensors that monitors the system under investigation. This thesis explores an approach termed “ad hoc distributed simulation,” which is based on embedding online simulations into a sensor network and adding communication and synchronization among simulators to model operational systems. This approach offers several potential advantages over existing approaches: (1) it can provide rapid response to system dynamics as well as efficiency since data exchange is local to the sensor network, (2) it can achieve better scalability to incorporate more sensors, and (3) it can provide better robustness to failures because portions of the system are still under local control. This research addresses several statistical issues in this ad hoc approach: (1) rapid and effective estimation of the input processes at model boundaries, (2) estimation of system-wide performance measures from individual simulator outputs, and (3) correction mechanisms responding to unexpected events or inaccuracies within the model. This thesis examines ad hoc distributed simulation analytically and experimentally, mainly focusing on the accuracy of predicting the performance of open queueing networks. First, the analytical part formalizes the ad hoc approach and evaluates its accuracy at modeling certain class of open queueing networks with regard to the steady-state system performance measures. This work concerning steady-state metrics is extended to a broader class of networks by an empirical study, which presents evidence to show that the ad hoc approach can generate predictions comparable to those from sequential simulations. Furthermore, a “buffered-area” mechanism is proposed to substantially reduce prediction bias with a moderate increase in execution time. In addition to those steady-state studies, another empirical study targets the prediction accuracy of the ad hoc approach at open queueing networks with short-term system-state transients. This study demonstrates that, with slight modification to the prior design of the ad hoc queueing simulation method for those steady-state studies, system dynamics can be well modeled. The results, again, support the conclusion that the ad hoc approach is competitive to the sequential simulation method in terms of prediction accuracy.

No / This chapter gives an introduction to protein simulation methodology aimed at experimentalists and graduate students new to in silico investigations. More emphasis is placed on the knowledge needed to select appropriate simulation protocols, leaving theoretical and mathematical depth for other texts to take care of. The chapter explains some of the more practical considerations of performing simulations of proteins, in particular, the additional considerations required when studying protein folding where nonnative environments are modeled. Forced unfolding simulations are highly relevant and invaluable in characterizing proteins naturally exposed to mechanical stress as a component of their biological function. The chapter illustrates this utility by discussing research that has been done primarily on the giant muscle protein titin. Using Molecular dynamics (MD) simulations to investigate protein folding faces two main challenges. The most obvious relates to the timescale of protein folding and the computational expense required for adequate sampling. / NIH

No description available.

O assunto a ser tratado neste trabalho é a relação entre o crescimento econômico e a restrição externa. O objetivo do trabalho é construir um modelo macroeconômico de simulação que sirva de instrumento de análise, ainda que modesto, da relação entre os componentes de Demanda Agregada (DA) e as variáveis do Balanço de Pagamentos (BP) da economia brasileira no período 1947-2006. O modelo baseia-se no Princípio da Demanda Efetiva (PDE) formalizado inicialmente por Keynes e Kalecki, através do qual Thirlwall (1979) derivou um resultado geral de como a restrição de equilíbrio do Balanço de Pagamentos (BP) limita o crescimento de uma economia no longo prazo. A Teoria de Dinâmica de Sistemas (DS) constitui a base metodológica para abordar esse tema. Essa é uma teoria de modelagem e simulação de sistemas complexos, e a sua utilização permitirá tratar de forma integrada as variáveis a serem analisadas. No final do trabalho, apresentar-se-ão algumas simulações com o objetivo de identificar o impacto de cenários alternativos (com mudança de parâmetros e condições iniciais) sobre a taxa de crescimento da economia no período 1947-2006. / The matter to be treated in this work is the relationship between economic growth and foreign restriction. The objective is to build a macroeconomic simulation model to serve as a tool for analysis, though modest,of the relationship between the components of Aggregate Demand and the variables of the Balance of Payments of the Brazilian economy in the period 1947-2006. The model is based on the Principle of Effective Demand, formalized initially by Keynes and Kalecki, through which Thirlwall (1979) derived a general result of how the restriction of the Balance of Payments limits growth of an economy in the long run. The Theory of System Dynamics forms the methodological basis for addressing this theme. This is a theory of modeling and simulation of complex systems, and its use will allow to treat the variables to be examined in an integrated way. At the end of the work it will be presented some simulations with the goal of identifying the impact of alternative scenarios (with change of parameters and initial conditions) on the growth rate of the economy in the period 1947-2006.

O assunto a ser tratado neste trabalho é a relação entre o crescimento econômico e a restrição externa. O objetivo do trabalho é construir um modelo macroeconômico de simulação que sirva de instrumento de análise, ainda que modesto, da relação entre os componentes de Demanda Agregada (DA) e as variáveis do Balanço de Pagamentos (BP) da economia brasileira no período 1947-2006. O modelo baseia-se no Princípio da Demanda Efetiva (PDE) formalizado inicialmente por Keynes e Kalecki, através do qual Thirlwall (1979) derivou um resultado geral de como a restrição de equilíbrio do Balanço de Pagamentos (BP) limita o crescimento de uma economia no longo prazo. A Teoria de Dinâmica de Sistemas (DS) constitui a base metodológica para abordar esse tema. Essa é uma teoria de modelagem e simulação de sistemas complexos, e a sua utilização permitirá tratar de forma integrada as variáveis a serem analisadas. No final do trabalho, apresentar-se-ão algumas simulações com o objetivo de identificar o impacto de cenários alternativos (com mudança de parâmetros e condições iniciais) sobre a taxa de crescimento da economia no período 1947-2006. / The matter to be treated in this work is the relationship between economic growth and foreign restriction. The objective is to build a macroeconomic simulation model to serve as a tool for analysis, though modest,of the relationship between the components of Aggregate Demand and the variables of the Balance of Payments of the Brazilian economy in the period 1947-2006. The model is based on the Principle of Effective Demand, formalized initially by Keynes and Kalecki, through which Thirlwall (1979) derived a general result of how the restriction of the Balance of Payments limits growth of an economy in the long run. The Theory of System Dynamics forms the methodological basis for addressing this theme. This is a theory of modeling and simulation of complex systems, and its use will allow to treat the variables to be examined in an integrated way. At the end of the work it will be presented some simulations with the goal of identifying the impact of alternative scenarios (with change of parameters and initial conditions) on the growth rate of the economy in the period 1947-2006.

The optimization of production has come a long way in the last few years. From having to implement new production philosophies directly into the production, today you can simply build a simulation on the computer that can be used to test new solutions. This makes it cheaper and less time-consuming to improve production. This report will describe the thesis work made by two students from Lulea University of Technology studying mechanical engineering with orientation production technology. The thesis work was made at Boliden MineralsAB during the spring term of 2021. This master thesis aim is to look at the potential of using discrete-event simulation as a tool to test different production philosophies. To do this, a simulation model is built to represent Boliden’s mining operation. The focus will be on the Cut and fill process, and how vehicles and operators are dispatched. From interviews, videos and information gave by Boliden a current state analysis was done to get a good understanding of the situation and how the process works. This combined with a litterateur study a good foundation was made to start building the simulation. Since this is the first time Boliden uses simulation on the cut and fill process in this manner, there’s been close contact with Boliden to validate and verify the models. The different production scenarios that were simulated were selected with the guidance of Boliden to look at the most relevant areas for them. Firstly, a base model was constructed, this model had a number of restrictions compared to the real-life process. With data from previous work that Boliden had with simulation models, the base model could be controlled that it worked properly. From this model others, models could be build-up, with the difference of using another production control philosophy for the simulation. By using these philosophies there could be determined an increase by 1% in productivity when prioritizing operators to the bottleneck of the process to maximize utilization.

Adaptive reuse of parametric finite element analysis (FEA) models is a common form of reuse that involves integrating new information into an archived FEA model to apply it towards a new similar physical problem. Adaptive reuse of archived FEA models is often motivated by the need to assess the impact of minor improvements to component-based designs such as addition of new structural components, or the need to assess new failure modes that arise when a device is redesigned for new operating environments or loading conditions. Successful adaptive reuse of FEA models involves reference to supporting documents that capture the formulation of the model to determine what new information can be integrated and how. However, FEA models and supporting documents are not stored in formats that are semantically rich enough to support automated inference of their relevance to a modelers needs. The modelers inability to precisely describe information needs and execute queries based on such requirements results in inefficient queries and time spent manually assessing irrelevant models. The central research question in this research is thus how do we incorporate a modelers intent into automated retrieval of FEA models for adaptive reuse? An automated retrieval method to support adaptive reuse of parametric FEA models has been developed in the research documented in this thesis. The method consists of a classification-based retrieval method based on ALE subsumption hierarchies that classify models using semantically rich description logic representations of physical problem structure and a reusability-based ranking method. Conceptual data models have been developed for the representations that support both retrieval and ranking of archived FEA models. The method is validated using representations of FEA models of several classes of electronic chip packages. Experimental results indicate that the properties of the representation methods support effective automation of retrieval functions for FEA models of component-based designs.