• 제목/요약/키워드: Discrete-event simulation

검색결과 397건 처리시간 0.024초

순방향 WCDMA 채널에서 AMR 음성 트래픽의 품질 보증 모델 (Quality of Service Assurance Model for AMR Voice Traffic in Downlink WCDMA System)

  • 정성환;홍정완;이창훈
    • 대한산업공학회지
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    • 제33권2호
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    • pp.191-200
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    • 2007
  • We propose the QoS (Quality of Service) assurance model for AMR (Adaptive MultiRate) voice users considering the capacity and service quality jointly in downlink WCDMA system. For this purpose, we introduce a new system performance measure and the number-based AMR mode allocation scheme. The proposed number-based AMR mode allocation can be operated only with the information of total number of ongoing users. Therefore, it can be more simply implemented than the existing power-based allocation. The proposed system performance measure considers the stochastic variations of AMR modes of ongoing users and can be analytically obtained using CTMC (Continuous Time Markov Chain) modeling. In order to validate the proposed analytical model, a discrete event-based simulation model is also developed. The performance measure obtained from the analytical model is in agreement with the simulation results and is expected to be useful for parameter optimization.

합성환경 기반 교전모의 (A Synthetic Enviornment Based Engagement Simulation Model)

  • 박상철;성길영
    • 한국CDE학회논문집
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    • 제15권4호
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    • pp.271-278
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    • 2010
  • Weapon systems for future war require operating various war scenarios that are getting complex. Similarly, modeling and simulation technique is getting attention to acquire more effective weapon systems. Several S/W tools exist for simulating small scale engagements which depict a kind of war. However, it is very hard to model combat objects more systematic, and reuse them. To overcome these difficulties, this paper presents a modeling methodology for simulating small scale engagement using the DEVS-formalism. In this paper, we systematically classified and defined combat objects, likewise, explain a framework for a small scale combat simulation.

확장성을 고려한 계층적 시스템 성능 모델 및 시뮬레이션 (Hierarchical Performance Modeling and Simulation of Scalable Computer System)

  • 김흥준
    • 한국시뮬레이션학회논문지
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    • 제4권2호
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    • pp.1-16
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    • 1995
  • The performance of a computer system depends on the system architecture and workload, and the high performance required in many applications can be achieved by the scalability of the system architecture and workload. This paper presents scalable workload, a performance metric of scalable speedup and hierarchical modeling for the scalable computer system as well as the development of the object-oriented simulator spmplC++ Which is an advanced C++ version of the discrete event-driven simulation environment smplE. In addition, this paper presents two examples of applying scalable speedup, hierarchical modeling and simulator smplC++ to analyze the performance effect of the sclcbility in a multiprocessor system and a network-based client/server system.

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계층의 구조를 갖는 시뮬레이션 모델에 있어서 단계적 접근을 위한 모델연결 방법론과 그 적용 예 (Model Coupling Technique for Level Access in Hierarchical Simulation Models and Its Applications)

  • 조대호
    • 한국시뮬레이션학회논문지
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    • 제5권2호
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    • pp.25-40
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    • 1996
  • Modeling of systems for intensive knowledge-based processing requires a modeling methodology that makes efficient access to the information in huge data base models. The proposed level access mothodology is a modeling approach applicable to systems where data is stored in a hierarchical and modular modules of active memory cells(processor/memory pairs). It significantly reduces the effort required to create discrete event simulation models constructed in hierarchical, modular fashion for above application. Level access mothodology achieves parallel access to models within the modular, hierarchical modules(clusters) by broadcasting the desired operations(e.g. querying information, storing data and so on) to all the cells below a certain desired hierarchical level. Level access methodology exploits the capabilities of object-oriented programming to provide a flexible communication paradigm that combines port-to-port coupling with name-directed massaging. Several examples are given to illustrate the utility of the methodology.

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공개키 기반 구조에서의 효율적인 인증서 상태 검증 방법에 관한 모델링 및 시뮬레이션 (Modeling and Simulation of the Efficient Certificate Status Validation System on Public Key Infrastructure)

  • 최지혜;조대호
    • 한국시뮬레이션학회:학술대회논문집
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    • 한국시뮬레이션학회 2004년도 춘계학술대회 논문집
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    • pp.7-12
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    • 2004
  • 공개키 기반 구조(PKI; Public Key Infrastructure)에 필수적인 요소인 인증서의 상태 검증에 있어서 인증서 상태 검증 서버인 OCSP (Online Certificate Status Protocol) 서버는 실시간 상태 검증을 제공한다. 그러나, 서버와 클라이언트의 메시지 인증을 위해 전자 서명을 수행해야 하며, 이 때 사용되는 공개 암호 연산 과정의 복잡성은 동시에 많은 클라이언트의 요청이 발생할 경우에 응답 시간을 크게 지연시킨다는 단점을 가지고 있다. 본 논문에서는 이러한 문제를 해결하기 위한 인증서 상태 검증 서버의 시뮬레이션 모델을 DEVS (Discrete Event system Specification) 방법론을 이용하여 설계하였다. 이 모델은 인증서의 상태 검증을 요청하는 영역에 위치하여 해쉬 함수를 적용한 인증을 수행하도록 구성되었으며, 시뮬레이션 결과는 제시한 방법이 인증서 상태 검증 속도를 증대시켜 결과적으로 사용자의 응답 시간이 감소되는 것을 보여준다.

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봉쇄와 교착이 존재하는 시스템의 성능분석을 위한 페트리-네트 기반 모의실험 소프트웨어 개발 (Development of a Petri-net-based Simulation Software for Performance Evaluation of the System with Blocking and Deadlock)

  • 박찬우;황상철;이효성
    • 한국시뮬레이션학회논문지
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    • 제9권1호
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    • pp.67-81
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    • 2000
  • In this paper, a new software package for modeling and simulating discrete-event dynamic systems is developed. The new software is a general-purpose, graphical tool based on timed Petri-nets and is developed using Visual Basic and Visual C++ for the window environment. It allows the user to graphically build a Petri-net model and enter input data for executing the Petri-net simulation model. It is equipped with a deadlock detection and recovery function as well as an automatic error check function. In addition, the software supports various enabling functions and distribution functions and provides various statistics for the performance measures of interests pertaining to the system. We expect the new software will be used in a wide number of applications including computer, communication and manufacturing systems.

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RAID 시스템의 모델링 및 시뮬레이션 (Modeling and Simulation of a RAID System)

  • 이찬수;성영락;오하령
    • 한국시뮬레이션학회:학술대회논문집
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    • 한국시뮬레이션학회 2001년도 춘계 학술대회 논문집
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    • pp.77-81
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    • 2001
  • In this paper, a RAID system is modeled and simulated by using the DEVS formalism. The RA[D system interacts with a host system by using the high-speed Fibre channel protocol and stores input data in an array of IDE disks. The DEVS formalism specifies discrete event systems in a hierarchical, modular manner. The RAID system model is composed of three units: primary-PCI unit, secondary-PCI unit and CPU unit. The primary-PCI unit interfaces with the host system and caches I/O data. The secondary-PCI unit includes disks. The CPU unit controls overall system. The control algorithm of CPU and PCI transactions are analyzed and modeled. From an analysis of simulation events, we can conclude that the proposed model satisfies given requirements.

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DEVS 모델과 사용자 요구사항의 일관성 검증 방법론 및 환경 구현 (Method and Implementation (or Consistency Verification of DEVS Model against User Requirement)

  • 김도형;김탁곤
    • 한국시뮬레이션학회:학술대회논문집
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    • 한국시뮬레이션학회 2005년도 춘계학술대회 논문집
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    • pp.100-105
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    • 2005
  • Development of complex discrete event simulators requires cooperation between domain experts and modeling experts who involve the development. With the cooperation the domain experts derive user requirement and modeling experts transform the requirement to a simulation model. This paper proposes a method for consistency verification of simulation model in DEVS formalism against the user requirement in UML diagrams. It also presents an automated tool, called VeriDEVS, which implements the proposed method. Inputs of VeriDEVS are three UML diagrams, namely use case, class and sequence diagrams, and DEVS Graph, all in Visio; outputs of a verification result is represented in PowerPoint files.

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RAID 시스템의 모델링 및 시뮬레이션 (Modeling and Simulation of a RAID System)

  • 이찬수;성영락;오하령
    • 한국시뮬레이션학회논문지
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    • 제11권1호
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    • pp.11-22
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    • 2002
  • In this paper, a RAID system is modeled and simulated by using the DEVS formalism. The RAID system interacts with a host system by using the high-speed Fibre channel protocol and stores data in an array of IDE disks. The DAVS formalism specifies discrete event systems in a hierarchical, modular manner. The RAID system model is composed of three units: primary-PCI unit, secondary-PCI unit and MCU unit. The primary-PCI unit interfaces with the host system and I/O data caches. The secondary-PCI unit includes disks. The MCU unit controls overall system. The control algorithm of MCU and PCI transactions are analyzed and modeled, From the analysis of simulation events, we can conclude that the proposed model satisfies given requirements.

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보안 모델의 연동을 위한 블랙보드구조의 적용 (An Application of Blackboard Architecture for the Coordination among the Security Systems)

  • 서희석;조대호
    • 한국시뮬레이션학회논문지
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    • 제11권4호
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    • pp.91-105
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    • 2002
  • The attackers on Internet-connected systems we are seeing today are more serious and technically complex than those in the past. So it is beyond the scope of amy one system to deal with the intrusions. That the multiple IDSes (Intrusion Detection System) coordinate by sharing attacker's information for the effective detection of the intrusion is the effective method for improving the intrusion detection performance. The system which uses BBA (BlackBoard Architecture) for the information sharing can be easily expanded by adding new agents and increasing the number of BB (BlackBoard) levels. Moreover the subdivided levels of blackboard enhance the sensitivity of the intrusion detection. For the simulation, security models are constructed based on the DEVS (Discrete EVent system Specification) formalism. The intrusion detection agent uses the ES (Expert System). The intrusion detection system detects the intrusions using the blackboard and the firewall responses these detection information.

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