A Web-based Distance Learning System in Business Administration Experiences from an Inter-Nordic Course

The paper presents a specially constructed Web-based tool, WebGPSS, developed in Sweden, for teaching business students simulation. The tool includes a Java Applet that provides a Graphical Users Interface, by which the student can build a simulation model of a system, such as an inventory system. The model is then run on a remote server, which then sends result graphs and tables over the Web to the student computer. The paper furthermore discusses the experiences made when using this tool in a distance-learning course at the Norwegian School of Economics and Business Administration (NHH) in Bergen, in 2000 – 2002.Web-based; Distance learning; Simulation; GPSS; Java

GPSS interactive learning environment

This work presents an open source web environment to learn GPSS language in Modeling and Simulation courses. With this environment, students build their models by selecting entities and configuring them instead of programming GPSS codes from scratch. Teachers can also create models so that students can apply, analyze and interpret results. Thus, it includes a simulation engine that stores snapshots of models as they are executed, and allows students to navigate through these snapshots. The environment may be combined with existing learning management systems.Proyecto de Enlace de Bibliotecas (PREBI

GPSS interactive learning environment

This work presents an open source web environment to learn GPSS language in Modeling and Simulation courses. With this environment, students build their models by selecting entities and configuring them instead of programming GPSS codes from scratch. Teachers can also create models so that students can apply, analyze and interpret results. Thus, it includes a simulation engine that stores snapshots of models as they are executed, and allows students to navigate through these snapshots. The environment may be combined with existing learning management systems.Proyecto de Enlace de Bibliotecas (PrEBi

Simulación híbrida como núcleo de simulación de aplicaciones gráficas en tiempo real.

RESUMEN Las aplicaciones gráficas en tiempo real siguen un paradigma de simulación con- tinuo acoplado. Este paradigma presenta diversos inconvenientes, entre ellos cabe destacar el bajo aprovechamiento de la potencia de cálculo de la máquina, la im- posibilidad de de¯nir la QoS de cada objeto y mantenerla durante la ejecución o el acoplo de los procesos de todos los objetos del sistema, en particular el acoplo del proceso de visualización del sistema con el resto de procesos. La tesis propone cambiar el paradigma de simulación de estas aplicaciones a un paradigma discreto desacoplado. Este nuevo paradigma permite solucionar los pro- blemas del paradigma anterior. Los objetos de¯nen su propia QoS independiente- mente del resto del sistema, incluso se permite de¯nir diferentes QoS para diferentes aspectos del propio objeto. Entre estos objetos, est¶a el objeto visualizador, destina- do a controlar el proceso de visualización. El objeto visualizador también de¯ne su propia QoS. En el sistema discreto desacoplado cada objeto consume únicamente la poten- cia de cálculo estrictamente necesaria para llevar a cabo su simulación con la QoS de¯nida. Por ello, la potencia de cálculo del sistema se reparte entre los objetos en función de sus necesidades. El sistema puede adaptarse dinámicamente, rede¯niendo la QoS de los objetos en función de las condiciones de la ejecución del sistema. Los objetos pueden degradar o mejorar su comportamiento durante periodos de la ejecución para evitar colapsos del sistema o para mejorar el comportamiento del sistema. ____________________________________________________________________________________________________Real time graphic applications, speci¯cally videogames, follow a paradigm of continuous simulation that couple the simulation phase and the rendering phase. This paradigm can be ine±cient or it can produce incorrect simulations. It has di- sadvantages, some of them are: the inadequate computer power distribution between the graphic application objects, it is not possible to de¯ne the Quality of Service (QoS) of each application object, the object QoS can be maintained during the ap- plication running, the behavior of all the system objects are coupled (speci¯cally the rendering process and the simulation process). The proposal is to change the simulation paradigm of real time graphic ap- plications. The new simulation paradigm is discrete and decoupled. The use of a decoupled discrete paradigm avoids the problems of the continuous coupled para- digm and it avoids incorrect simulations, besides it improves the simulation quality and e±ciency. The discrete simulation paradigm allows to de¯ne a private QoS crite- rion for each aspect of each object in the videogame. The render object is dedicated to control the application render process. The render object de¯nes its own QoS criteria. It is possible to de¯ne a di®erent sampling frequency for each object aspect in the system. The discrete paradigm allows to de¯ne the objects sampling frequency to distribute the computer power adequately among the objects. The computer power consumed executing the application is only the necessary to guarantee the QoS of each object. The system can be adapted dynamically. The objects QoS can be adjusted to the objects requirements and the whole system requirements, the system load or characteristics. This sampling frequency may change dynamically to adapt the QoS of the object aspect to the real computer power. The result obtained is a discrete system that allows a Smart System Degradation and may rede¯ne dynamically the objects aspects QoS. Objects collect system information and use it to adapt its QoS

A grid computing framework for commercial simulation packages

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.An increased need for collaborative research among different organizations, together with continuing advances in communication technology and computer hardware, has facilitated the development of distributed systems that can provide users non-trivial access to geographically dispersed computing resources (processors, storage, applications, data, instruments, etc.) that are administered in multiple computer domains. The term grid computing or grids is popularly used to refer to such distributed systems. A broader definition of grid computing includes the use of computing resources within an organization for running organization-specific applications. This research is in the context of using grid computing within an enterprise to maximize the use of available hardware and software resources for processing enterprise applications. Large scale scientific simulations have traditionally been the primary benefactor of grid computing. The application of this technology to simulation in industry has, however, been negligible. This research investigates how grid technology can be effectively exploited by simulation practitioners using Windows-based commercially available simulation packages to model simulations in industry. These packages are commonly referred to as Commercial Off-The-Shelf (COTS) Simulation Packages (CSPs). The study identifies several higher level grid services that could be potentially used to support the practise of simulation in industry. It proposes a grid computing framework to investigate these services in the context of CSP-based simulations. This framework is called the CSP-Grid Computing (CSP-GC) Framework. Each identified higher level grid service in this framework is referred to as a CSP-specific service. A total of six case studies are presented to experimentally evaluate how grid computing technologies can be used together with unmodified simulation packages to support some of the CSP-specific services. The contribution of this thesis is the CSP-GC framework that identifies how simulation practise in industry may benefit from the use of grid technology. A further contribution is the recognition of specific grid computing software (grid middleware) that can possibly be used together with existing CSPs to provide grid support. With its focus on end-users and end-user tools, it is intended that this research will encourage wider adoption of grid computing in the workplace and that simulation users will derive benefit from using this technology

Historia, evolución y perspectivas de futuro en la utilización de técnicas de simulación en la gestión portuaria: aplicaciones en el análisis de operaciones, estrategia y planificación portuaria

Programa Oficial de Doutoramento en Análise Económica e Estratexia Empresarial. 5033V0[Resumen] Las técnicas de simulación, tal y como hoy las conocemos, comenzaron a mediados del siglo XX; primero con la aparición del primer computador y el desarrollo del método Monte Carlo, y más tarde con el desarrollo del primer simulador de propósito específico conocido como GPS y desarrollado por Geoffrey Gordon en IBM y la publicación del primer texto completo dedicado a esta materia y llamado the Art of Simulation (K.D. Tocher, 1963). Estás técnicas han evolucionado de una manera extraordinaria y hoy en día están plenamente implementadas en diversos campos de actividad. Las instalaciones portuarias no han escapado de esta tendencia, especialmente las dedicadas al tráfico de contenedores. Efectivamente, las características intrínsecas de este sector económico, le hacen un candidato idóneo para la implementación de modelos de simulación con propósitos y alcances muy diversos. No existe, sin embargo y hasta lo que conocemos, un trabajo científico que compile y analice pormenorizadamente tanto la historia como la evolución de simulación en ambientes portuarios, ayudando a clasificar los mismos y determinar cómo estos pueden ayudar en el análisis económico de estas instalaciones y en la formulación de las oportunas estrategias empresariales. Este es el objetivo último de la presente tesis doctoral.[Resumo] As técnicas de simulación, tal e como hoxe as coñecemos, comezaron a mediados do século XX; primeiro coa aparición do computador e o desenvolvemento do método Monte Carlo e máis tarde co desenvolvemento do primeiro simulador de propósito específico coñecido como GPS e desenvolvido por Geoffrey Gordon en IBM e a publicación do primeiro texto completo dedicado a este tema chamado “A Arte da Simulación” (K.D. Tocher, 1963). Estas técnicas evolucionaron dun xeito extraordinario e hoxe en día están plenamente implementadas en diversos campos de actividade. As instalacións portuarias non escaparon desta tendencia, especialmente as dedicadas ao tráfico de contenedores. Efectivamente, as características intrínsecas deste sector económico, fanlle un candidato idóneo para a implementación de modelos de simulación con propósitos e alcances moi variados. Con todo, e ata o que coñecemos, non existe un traballo científico que compila e analiza de forma detallada tanto a historia como a evolución da simulación en estes ambientes portuarios, clasificando os mesmos e determinando como estes poden axudar na análise económica destas instalacións e na formulación das oportunas estratexias empresariais. Este é o último obxectivo da presente tese doutoral.[Abstract] Simulation, to the extend that we understand it nowadays, began in the middle of the 20th century; first with the appearance of the computer and the development of the Monte Carlo method, and later with the development of the first specific purpose simulator known as GPS developed by Geoffrey Gordon in IBM. This author published the first full text devoted to this subject “The Art of Simulation” in 1963. These techniques have evolved in an extraordinary way and nowadays they are fully implemented in different fields of activity. Port facilities have not escaped this trend, especially those dedicated to container traffic. Indeed, the intrinsic characteristics of this economic sector, make it a suitable candidate for the implementation of simulation with very different purposes and scope. However, to the best of our knowelegde, there is not a scientific work that compiles and analyzes in detail both, the history and the evolution of simulation in port environments, contributing to classify them and determine how they can help in the economic analysis of these facilities and in the formulation of different business strategies. This is the ultimate goal of this doctoral thesis

Distributed Simulation in Industry

Csaba Attila Boer was born in Satu Mare, Romania, on 29 October, 1975. He completed his secondary education at Kölcsey Ferenc High School, in Satu Mare, in 1994. In the same year he started his higher education at Babeş-Bolyai University, Faculty of Mathematics and Computer Science, Cluj-Napoca, Romania, where he received his B.Sc. degree in Computer Science, in 1998, and his M.Sc. degree with major in Information Systems, specialization Designing and Implementing Complex Systems, in 1999. During these years, he obtained fellowships at the Eötvös Lóránd University, and at the Computer and Automation Research Institute of the Hungarian Academy of Sciences, Budapest, Hungary within the Central European Exchange Program for University Studies (CEEPUS). Since 1999, he has been affiliated with the Computer Science Department, Faculty of Economics at Erasmus University Rotterdam, The Netherlands. There, he worked as a researcher for one year, studying the storage and retrieval of discrete event simulation models, research that resulted in three scientific articles. Between 2000 and 2004, he was associated with the same department as a Ph.D. candidate aiming to research the area of distributed simulation and its application in industry. His topic being close to the research carried out at the Faculty of Technology, Policy and Management, Delft University of Technology, and the BETADE research program, he started to collaborate with researchers from these groups, getting involved in two joint practical case study projects. This collaboration resulted in seven joint scientific articles, presented at various international conferences. Furthermore, Csaba has maintained international contacts with researchers from the distributed simulation area. He has been invited twice to Brunel University, London to give a presentation concerning the application of distributed simulation in industry. Currently, he is working as a simulation consultant atGedistribueerde simulatie wordt binnen de defensie in brede kring geaccepteerd en toegepast, maar het heeft in de industrie geen voet aan de grond gekregen. In dit proefschrift onderzoeken we de redenen voor dit fenomeen door te bestuderen wat de industrie verwacht op het terrein van de gedistribueerde simulatie. In het algemeen worden in de industrie simulatiemodellen ontworpen en ontwikkeld met COTS (“commercial-off-the-shelf”) simulatiepakketten. Echter, de bestaande architecturen voor gedistribueerde simulatie binnen defensie zijn niet gericht op het koppelen van modellen gebouwd met COTS simulatiepakketten. Om de industrie te motiveren gedistribueerde simulatie te accepteren en te gebruiken moet men derhalve ernaar streven het mogelijk te maken om modellen, die gebouwd zijn met deze pakketten, aan elkaar te koppelen zonder dat dat al te veel inspanning vereist van de modelbouwers. Uitgaande van een onderzoek onder experts in dit domein, stellen we in dit proefschrift een pakket van eisen voor voor het ontwerp en ontwikkelen van gedistribueerde simulatiearchitecturen dat de industriegemeenschap zal motiveren om gedistribueerde simulatie te accepteren en toe te passen. Daarnaast presenteren we een lichtgewicht architectuur voor gedistribueerde simulatie die met succes toegepast is in twee industriële projecten, en die in grote mate voldoet aan het voorgestelde pakket van eisen.While distributed simulation is widely accepted and applied in defence, it has not gathered ground yet in industry. In this thesis we investigate the reasons behind this phenomenon by surveying the expectation of industry with respect to distributed simulation solutions. Simulation models in industry are mainly designed and developed in commercial-off-the-shelf (COTS) simulation packages. The existing distributed simulation architectures in defence, however, do not focus on coupling models created in COTS simulation packages. Therefore, in order to motivate the industrial community to easily accept and use distributed simulation, one should strive to couple models built in these packages. Further, coupling these models should be possible without needing too much extra effort from modellers. In this thesis, based on a survey with experts in domain, we propose a list of requirements for designing and developing distributed simulation architectures that would encourage the industrial community to accept and apply distributed simulation. Furthermore, we present a lightweight distributed simulation architecture which has been successfully applied in two industrial projects, and satisfies to a large extent the proposed requirements

A grid computing framework for commercial simulation packages

An increased need for collaborative research among different organizations, together with continuing advances in communication technology and computer hardware, has facilitated the development of distributed systems that can provide users non-trivial access to geographically dispersed computing resources (processors, storage, applications, data, instruments, etc.) that are administered in multiple computer domains. The term grid computing or grids is popularly used to refer to such distributed systems. A broader definition of grid computing includes the use of computing resources within an organization for running organization-specific applications. This research is in the context of using grid computing within an enterprise to maximize the use of available hardware and software resources for processing enterprise applications. Large scale scientific simulations have traditionally been the primary benefactor of grid computing. The application of this technology to simulation in industry has, however, been negligible. This research investigates how grid technology can be effectively exploited by simulation practitioners using Windows-based commercially available simulation packages to model simulations in industry. These packages are commonly referred to as Commercial Off-The-Shelf (COTS) Simulation Packages (CSPs). The study identifies several higher level grid services that could be potentially used to support the practise of simulation in industry. It proposes a grid computing framework to investigate these services in the context of CSP-based simulations. This framework is called the CSP-Grid Computing (CSP-GC) Framework. Each identified higher level grid service in this framework is referred to as a CSP-specific service. A total of six case studies are presented to experimentally evaluate how grid computing technologies can be used together with unmodified simulation packages to support some of the CSP-specific services. The contribution of this thesis is the CSP-GC framework that identifies how simulation practise in industry may benefit from the use of grid technology. A further contribution is the recognition of specific grid computing software (grid middleware) that can possibly be used together with existing CSPs to provide grid support. With its focus on end-users and end-user tools, it is intended that this research will encourage wider adoption of grid computing in the workplace and that simulation users will derive benefit from using this technology.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

MULTIPLE DISCRETE-EVENT SIMULATION AND ANIMATION MODELS TO ASSIST MODERN MINING OPERATIONS

This research investigation was conducted to develop, execute, and analyze a collection of discrete-event system simulation and animation models for different modern mining operations and systems, including two open-pit gold mines, an aggregate mine (sand and gravel), an open-cast (strip) coal mine, and an underground mine evacuation operation. The mine simulation and animation models aimed to study and assess a wide range of practical unique and common "what if?" scenarios that the mine engineers and managers of the case studies posed in different aspects during the research. A comprehensive and detailed literature review was also performed to provide a summary of the published discrete-event system simulation projects and their applications in the mining and mineral industry. The simulation results of the investigation were effectively implemented to assist the engineers in maximizing the productivity of the mines, improving the operation processes, reducing the environmental impact of the haulage operations, and enhancing the equipment utilization in various case studies. In addition, due to the shortage of powerful and flexible computer simulation tools in designing and analyzing underground mining evacuation operations and rescue equipment with respect to the mine operating characteristics and layout, the discrete-event system simulation and animation technique was innovatively implemented for modeling these complex systems. GPSS/H® and PROOF Professional® were the simulation language and animation software used for this research work

The responsive reply chain: the influence of the positioning of decoupling points

Manufacturing supply chains have been challenged by high competition, dynamic, and stochastic conditions. They have to be constantly responsive in today’s ever-changing manufacturing environment. The proper positioning of decoupling points for material flow and information flow has a significant potential for increasing responsiveness in a supply chain. Positioning the material decoupling point as close to the end consumer as possible whilst the information decoupling point is positioned upstream is the key to the industries’ ability to reduce lead time and enhance performance in the dynamic behaviour of the supply chain. [Continues.