172,672 research outputs found

    Automatic Generation of Distributed System Simulations from UML

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    Nowadays, an object-oriented approach is commonly used for building computer systems. The benefits of the object-oriented method, such as scalability, stability and reusability, make this method suitable for building complex systems, including those in the distributed system area. A distributed system application usually needs to satisfy quite stringent requirements such as reliability, availability, security, etc. and the cost of building such an application will be quite high. It is therefore desirable to be able to predict the performance of the proposed system before the construction begins. In order to do this, it is important to evaluate the requirements of the new system and translate them into a specification (design). The design process helps the system developers to understand the requirements better as well as to avoid misconceptions about the system. From the specification, a simulation program can be built to mimic the execution of the proposed system. The simulation run provides some data about the states of the system and from these data, the performance of the system can be predicted and analysed. UML (Unified Modeling Language) is one example of the object-oriented design methods that has been widely used for specifying system requirements. There are also some object-oriented simulation languages/packages available, for example, SIMULA or C++SIM package, but it is often difficult to transform the system’ s requirements into a simulation program without sound knowledge of some simulation techniques. On top of that, a new simulation program needs to be built each time for different systems, which can be quite tedious. The currently available UML tools do not provide a feature to generate simulation programs automatically from UML specifications. In this paper, we describe a tool for constructing simulation programs in a generic way, based on a simple specification (preferably in a UML notation) by identifying the simulation components and their structure

    DEVELOPMENT OF AN OBJECT-ORIENTED FRAMEWORK FOR MODULAR CHEMICAL PROCESS SIMULATION WITH SEMICONDUCTOR MANUFACTURING APPLICATIONS

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    Chemical Vapor Deposition (CVD) processes constitute an important unit operation for micro electronic device fabrication in the semiconductor industry. Simulators of the deposition process are powerful tools for understanding the transport and reaction conditions inside the deposition chamber and can be used to optimize and control the deposition process. This thesis discusses the development of a set of object-oriented modular simulation tools for solving lumped and spatially distributed models generated from chemical process design and simulation problems. The application of object-oriented design and modular approach greatly reduces the software development cycle time associated with designing process systems and improves the overall efficiency of the simulation process. The framework facilitates an evolutionary approach to simulator development, starting with a simple process description and building model complexity and testing modeling hypothesis in a step-by-step manner. Modularized components can be easily assembled to form a modeling system for a desired process. The framework also brings a fresh approach to many traditional scientific computing procedures to make a greater range of computational tools available for solving engineering problems. Two examples of tungsten chemical vapor deposition simulation are presented to illustrate the capability of the tools developed to facilitate an evolutionary simulation approach. The first example demonstrates how the framework is applied for solving systems assembled from separate modules by simulating a tungsten CVD deposition process occurring in a single wafer LPCVD system both at steady-state and dynamically over a true processing cycle. The second example considers the development of a multi-segment simulator describing the gas concentration profiles in the newly designed Programmable CVD reactor system. The simulation model is validated by deposition experiments conducted in the three-segment prototype. To facilitate the CVD system design, experimental data archiving, and distributed simulation, a three-tier Java and XML-based integrated information technology system has also been developed

    Toolkit for Simulation Modeling of Logistics Warehouse in Distributed Computing Environment

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    We address an important problem of an automation of logistics warehouses simulation modeling in distributed service-oriented computing environments. To this end, we propose new approach for adjusting management system parameters of real warehouse in production use. It is based on the integration of the conceptual, wireframe and service-oriented programming used to develop parameter sweep applications and data analysis in the simulation modeling process. We develop a toolkit for supporting modeling of warehouse logistics. The practical experiments are focused upon the refrigerated warehouse. The developed application demonstrates high efficiency and scalability for optimizing nine criteria to cope with different production demands.The study was supported by the Russian Foundation of Basic Research, projects no. 15-29-07955 and no. 16-07-00931, and Program 1.33P of fundamental research of Presidium RAS, project “Development of new approaches to creation and study of complex models of information-computational and dynamic systems with applications”

    Densifying the sparse cloud SimSaaS: The need of a synergy among agent-directed simulation, SimSaaS and HLA

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    Modelling & Simulation (M&S) is broadly used in real scenarios where making physical modifications could be highly expensive. With the so-called Simulation Software-as-a-Service (SimSaaS), researchers could take advantage of the huge amount of resource that cloud computing provides. Even so, studying and analysing a problem through simulation may need several simulation tools, hence raising interoperability issues. Having this in mind, IEEE developed a standard for interoperability among simulators named High Level Architecture (HLA). Moreover, the multi-agent system approach has become recognised as a convenient approach for modelling and simulating complex systems. Despite all the recent works and acceptance of these technologies, there is still a great lack of work regarding synergies among them. This paper shows by means of a literature review this lack of work or, in other words, the sparse Cloud SimSaaS. The literature review and the resulting taxonomy are the main contributions of this paper, as they provide a research agenda illustrating future research opportunities and trends

    A State-of-the-art Integrated Transportation Simulation Platform

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    Nowadays, universities and companies have a huge need for simulation and modelling methodologies. In the particular case of traffic and transportation, making physical modifications to the real traffic networks could be highly expensive, dependent on political decisions and could be highly disruptive to the environment. However, while studying a specific domain or problem, analysing a problem through simulation may not be trivial and may need several simulation tools, hence raising interoperability issues. To overcome these problems, we propose an agent-directed transportation simulation platform, through the cloud, by means of services. We intend to use the IEEE standard HLA (High Level Architecture) for simulators interoperability and agents for controlling and coordination. Our motivations are to allow multiresolution analysis of complex domains, to allow experts to collaborate on the analysis of a common problem and to allow co-simulation and synergy of different application domains. This paper will start by presenting some preliminary background concepts to help better understand the scope of this work. After that, the results of a literature review is shown. Finally, the general architecture of a transportation simulation platform is proposed
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