1,945 research outputs found

    A study of the reduction of simulation modeling development time

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    This paper presents new ideas dealing with simulation model development that are derived from the principles of lean manufacturing, for example, the concept of treating the time that is spent in production activities as lead-time, and the feasibility of reducing the lead-time through different mechanisms, which are presented in a framework [44]. One of the main obstacles in developing simulation model is time. Simulation lead-time is composed of nine steps of simulation model development. These steps are: problem definition, establishing boundaries, establishing variables, data collection, model development, verification & validation, documentation, experimentation, and implementation. This paper presents the idea of treating the time spent in simulation modeling development as a lead-time. At the same time, it presents a new framework to reduce lead-time, which has never been addressed before. A new framework to reduce the simulation modeling development long lead-time similar to the Toyota production framework for reducing the production lead-time will be presented in this paperThe framework developed as a result of an actual simulation case study, which took place at a local company, and which took a very long lead-time. The framework was composed of different steps, techniques, and mechanisms that should reduce simulation modeling development lead-time every time a simulation project is conducted. One of the goals of this framework is to reduce one of the main obstacles of simulation model, which is the long lead-time. One of the new mechanisms that is presented in this framework is a geographical distributed communication tool, which is called NetMeeting. This tool is an application of the concept of distributed and Web-Based simulations

    Design, Implementation and Verification Using UML-RT in GSM Radio Base Station 2000

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    This work deals with the issue of implementing a UML-RT standard, one of the latest notations for object oriented specification and design, in the developing-process of new real-time software for Radio Base Stations in the 2000 series at Ericsson. UML-RT is the real-time extension of the Unified Modeling Language (UML). The thesis investigates the design-, implementation- and verification-problems that exist when combining the current RT functions, Multi Platform Support, with the UML-RT tool, ObjecTime Developer. We describe UML, look at the advantages and disadvantages of using UML-RT tools and investigate current and future possibilities in ObjecTime Developer

    Mapping between Globes AEDL and A Particle-Oriented modeling

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    A brief poster presentation to introduce a modelling technique [1,2,3] that uses modeling-particles and its corresponding reactions in order to model generic computing systems. We propouse an automatic mapping between AEDL and P-O-Model in order to generate code in both areas

    Object-oriented GUI design of a modeling environment for logical discrete event systems

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    Ce mémoire porte sur la conception et l'implémentation d'une partie de l'interface personne-machine orientée objet d'un environnement de modélisation de systèmes réactifs appelé MELODIES (Modeling Environment for LOgical Discrete Event Systems ). Cet environnement permet la conception, l'analyse, la simulation et le contrôle de systèmes à événements discrets. L'architecture de l'interface est basée sur certaines idées empruntées au schéma de conception Model-View-Controller (MVC) et au paradigme JSP Model 2 Architecture . Il en résulte une nette séparation entre l'interface personne-machine, les structures de données ainsi que les fonctions sous-jacentes. L'adoption d'une approche orientée objet, comme celle supportée par VisualAge for Java 4.0, au lieu d'une approche orientée fichier supportée par plusieurs environnements de développement (par exemple JBuilder for Java 3.0) permet une plus grande convivialité et une meilleure organisation des artéfacts de modélisation. Afin de déployer cette interface sur différentes plateformes et d'assurer une rapidité d'exécution, la boîte à outils Qt 3.0 et le langage C++, avec sa librairie STL, ont été utilisés dans l'étape de codification. De plus, XML a été retenu comme langage de représentation de données afin de permettre un déploiement éventuel de MELODIES sur le Web

    Decentralized interaction and co-adaptation in the repeated prisoner's dilemma

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    The purpose of this paper is to propose a nonparametric interest rate term structure model and investigate its implications on term structure dynamics and prices of interest rate derivative securities. The nonparametric spot interest rate process is estimated from the observed short-term interest rates following a robust estimation procedure and the market price of interest rate risk is estimated as implied from the historical term structure data. That is, instead of imposing a priori restrictions on the model, data are allowed to speak for themselves, and at the same time the model retains a parsimonious structure and the computational tractability. The model is implemented using historical Canadian interest rate term structure data. The parametric models with closed form solutions for bond and bond option prices, namely the Vasicek (1977) and CIR (1985) models, are also estimated for comparison purpose. The empirical results not only provide strong evidence that the traditional spot interest rate models and market prices of interest rate risk are severely misspecified but also suggest that different model specifications have significant impact on term structure dynamics and prices of interest rate derivative securities.

    Army-NASA aircrew/aircraft integration program. Phase 5: A3I Man-Machine Integration Design and Analysis System (MIDAS) software concept document

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    This is the Software Concept Document for the Man-machine Integration Design and Analysis System (MIDAS) being developed as part of Phase V of the Army-NASA Aircrew/Aircraft Integration (A3I) Progam. The approach taken in this program since its inception in 1984 is that of incremental development with clearly defined phases. Phase 1 began in 1984 and subsequent phases have progressed at approximately 10-16 month intervals. Each phase of development consists of planning, setting requirements, preliminary design, detailed design, implementation, testing, demonstration and documentation. Phase 5 began with an off-site planning meeting in November, 1990. It is expected that Phase 5 development will be complete and ready for demonstration to invited visitors from industry, government and academia in May, 1992. This document, produced during the preliminary design period of Phase 5, is intended to record the top level design concept for MIDAS as it is currently conceived. This document has two main objectives: (1) to inform interested readers of the goals of the MIDAS Phase 5 development period, and (2) to serve as the initial version of the MIDAS design document which will be continuously updated as the design evolves. Since this document is written fairly early in the design period, many design issues still remain unresolved. Some of the unresolved issues are mentioned later in this document in the sections on specific components. Readers are cautioned that this is not a final design document and that, as the design of MIDAS matures, some of the design ideas recorded in this document will change. The final design will be documented in a detailed design document published after the demonstrations

    Terrain Representation And Reasoning In Computer Generated Forces : A Survey Of Computer Generated Forces Systems And How They Represent And Reason About Terrain

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    Report on a survey of computer systems used to produce realistic or intelligent behavior by autonomous entities in simulation systems. In particular, it is concerned with the data structures used by computer generated forces systems to represent terrain and the algorithmic approaches used by those systems to reason about terrain

    Proceedings of Monterey Workshop 2001 Engineering Automation for Sofware Intensive System Integration

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    The 2001 Monterey Workshop on Engineering Automation for Software Intensive System Integration was sponsored by the Office of Naval Research, Air Force Office of Scientific Research, Army Research Office and the Defense Advance Research Projects Agency. It is our pleasure to thank the workshop advisory and sponsors for their vision of a principled engineering solution for software and for their many-year tireless effort in supporting a series of workshops to bring everyone together.This workshop is the 8 in a series of International workshops. The workshop was held in Monterey Beach Hotel, Monterey, California during June 18-22, 2001. The general theme of the workshop has been to present and discuss research works that aims at increasing the practical impact of formal methods for software and systems engineering. The particular focus of this workshop was "Engineering Automation for Software Intensive System Integration". Previous workshops have been focused on issues including, "Real-time & Concurrent Systems", "Software Merging and Slicing", "Software Evolution", "Software Architecture", "Requirements Targeting Software" and "Modeling Software System Structures in a fastly moving scenario".Office of Naval ResearchAir Force Office of Scientific Research Army Research OfficeDefense Advanced Research Projects AgencyApproved for public release, distribution unlimite

    Hierarchical Control of the ATLAS Experiment

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    Control systems at High Energy Physics (HEP) experiments are becoming increasingly complex mainly due to the size, complexity and data volume associated to the front-end instrumentation. In particular, this becomes visible for the ATLAS experiment at the LHC accelerator at CERN. ATLAS will be the largest particle detector ever built, result of an international collaboration of more than 150 institutes. The experiment is composed of 9 different specialized sub-detectors that perform different tasks and have different requirements for operation. The system in charge of the safe and coherent operation of the whole experiment is called Detector Control System (DCS). This thesis presents the integration of the ATLAS DCS into a global control tree following the natural segmentation of the experiment into sub-detectors and smaller sub-systems. The integration of the many different systems composing the DCS includes issues such as: back-end organization, process model identification, fault detection, synchronization with external systems, automation of processes and supervisory control. Distributed control modeling is applied to the widely distributed devices that coexist in ATLAS. Thus, control is achieved by means of many distributed, autonomous and co-operative entities that are hierarchically organized and follow a finite-state machine logic. The key to integration of these systems lies in the so called Finite State Machine tool (FSM), which is based on two main enabling technologies: a SCADA product, and the State Manager Interface (SMI++) toolkit. The SMI++ toolkit has been already used with success in two previous HEP experiments providing functionality such as: an object-oriented language, a finite-state machine logic, an interface to develop expert systems, and a platform-independent communication protocol. This functionality is then used at all levels of the experiment operation process, ranging from the overall supervision down to device integration, enabling the overall sequencing and automation of the experiment. Although the experience gained in the past is an important input for the design of the detector's control hierarchy, further requirements arose due to the complexity and size of ATLAS. In total, around 200.000 channels will be supervised by the DCS and the final control tree will be hundreds of times bigger than any of the antecedents. Thus, in order to apply a hierarchical control model to the ATLAS DCS, a common approach has been proposed to ensure homogeneity between the large-scale distributed software ensembles of sub-detectors. A standard architecture and a human interface have been defined with emphasis on the early detection, monitoring and diagnosis of faults based on a dynamic fault-data mechanism. This mechanism relies on two parallel communication paths that manage the faults while providing a clear description of the detector conditions. The DCS information is split and handled by different types of SMI++ objects; whilst one path of objects manages the operational mode of the system, the other is to handle eventual faults. The proposed strategy has been validated through many different tests with positive results in both functionality and performance. This strategy has been successfully implemented and constitutes the ATLAS standard to build the global control tree. During the operation of the experiment, the DCS, responsible for the detector operation, must be synchronized with the data acquisition system which is in charge of the physics data taking process. The interaction between both systems has so far been limited, but becomes increasingly important as the detector nears completion. A prototype implementation, ready to be used during the sub-detector integration, has achieved data reconciliation by mapping the different segments of the data acquisition system into the DCS control tree. The adopted solution allows the data acquisition control applications to command different DCS sections independently and prevents incorrect physics data taking caused by a failure in a detector part. Finally, the human-machine interface presents and controls the DCS data in the ATLAS control room. The main challenges faced during the design and development phases were: how to support the operator in controlling this large system, how to maintain integration across many displays, and how to provide an effective navigation. These issues have been solved by combining the functionalities provided by both, the SCADA product and the FSM tool. The control hierarchy provides an intuitive structure for the organization of many different displays that are needed for the visualization of the experiment conditions. Each node in the tree represents a workspace that contains the functional information associated with its abstraction level within the hierarchy. By means of an effective navigation, any workspace of the control tree is accessible by the operator or detector expert within a common human interface layout. The interface is modular and flexible enough to be accommodated to new operational scenarios, fulfil the necessities of the different kind of users and facilitate the maintenance during the long lifetime of the detector of up to 20 years. The interface is in use since several months, and the sub-detector's control hierarchies, together with their associated displays, are currently being integrated into the common human-machine interface

    Semantic correlation of behavior for the interoperability of heterogeneous simulations

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    A desirable goal of military simulation training is to provide large scale or joint exercises to train personnel at higher echelons. To help meet this goal, many of the lower echelon combatants must consist of computer generated forces with some of these echelons composed of units from different simulations. The object of the research described is to correlate the behaviors of entities in different simulations so that they can interoperate with one another to support simulation training. Specific source behaviors can be translated to a form in terms of general behaviors which can then be correlated to any desired specific destination simulation behavior without prior knowledge of the pairing. The correlation, however, does not result in 100% effectiveness because most simulations have different semantics and were designed for different training needs. An ontology of general behaviors and behavior parameters, a database of source behaviors written in terms of these general behaviors with a database of destination behaviors. This comparison is based upon the similarity of sub-behaviors and the behavior parameters. Source behaviors/parameters may be deemed similar based upon their sub-behaviors or sub-parameters and their relationship (more specific or more general) to destination behaviors/parameters. As an additional constraint for correlation, a conversion path from all required destination parameters to a source parameter must be found in order for the behavior to be correlated and thus executed. The length of this conversion path often determines the similarity for behavior parameters, both source and destination. This research has shown, through a set of experiments, that heuristic metrics, in conjunction with a corresponding behavior and parameter ontology, are sufficient for the correlation of heterogeneous simulation behavior. These metrics successfully correlated known pairings provided by experts and provided reasonable correlations for behaviors that have no corresponding destination behavior. For different simulations, these metrics serve as a foundation for more complex methods of behavior correlation
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