• 한국시뮬레이션학회논문지
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• 제8권4호
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• pp.33-51
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• 1999

In this study, the system level network simulation is considered with adaptive array antenna in CDMA mobile communication system. A network simulation framework is implemented based on IS-95A/B system to consider dynamic handoff, system level network behavior, and deploying strategy into the overall CDMA mobile communication network under adaptive array algorithm. Its simulation model, such as vector channel model, adaptive beam forming antenna model, handoff model, and power control model, are described in detail with simulation block. In order to maximize SINR of received signal at antenna, Maximin algorithm is particularly considered, and it is computed at each simulation snap shot with SINR based power control and handoff algorithm. Graphic user interface in this system level network simulator is also implemented to define the simulation environments and to represent simulation results on real mapping system. This paper also shows some features of simulation framework and simulation results.

• 한국정보통신학회논문지
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• 제3권4호
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• pp.755-764
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• 1999

In this study, the system level network simulation is considered with adaptive array antenna in CDMA mobile communication system. A network simulation framework is implemented based on IS-95A/B system to consider dynamic handoff, system level network behavior, and deploying strategy into the overall CDMA mobile communication network under adaptive array algorithm. Its simulation model, such as vector channel model, adaptive beam forming antenna model, handoff model, and power control model, are described in detail with simulation block. In order to maximize SINR of received signal at antenna, maximin algorithm is particularly considered, and it is computed at each simulation snap shot with SINR based power control and handoff algorithm. Graphic user interface in this system level network simulator is also implemented to define the simulation environments and to represent simulation results on real mapping system. This paper also shows some features of simulation framework and simulation results.

• 한국군사과학기술학회지
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• 제19권2호
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• pp.244-251
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• 2016

In defense domain, mission level and engagement level simulation tools exist. In order to experiment a simulation scenario for obtaining results of both mission level and engagement level simulations, we should write a same simulation scenario in a mission level simulation tool as well as an engagement level simulation tool, and we have to operate these tools for analysis of each purpose. Moreover, we could not guarantee that these scenarios are completely same since each scenario is composed of different fidelities of simulation models, although the scenarios are written by a same experimenter and with same simulation purpose. To deal with the difficulties, I propose an approach to analysis of both mission level and engagement level simulations from one simulation result. For this, I have built Composite Combat Mission Planning Simulation Environment (CCMPSE). In this paper, the HLA/RTI based simulation composition technology and my experiences for the designed Composite Combat Mission Planning Simulation Control System (CCMPSCS) are explained. Moreover, This paper also conducts a case study with EADSIM, SADM, and the CCMPSCS. Finally, this paper provides lesson learned from the case study.

• 대한전자공학회논문지TC
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• 제41권7호
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• pp.21-30
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• 2004

WCDMA TDD 시스템의 Capacity는 주로 간섭에 의하여 제한되기 때문에, WCDMA TDD 시스템내의 간섭뿐만 아니라 인접 셀 간섭, 그리고 cdma2000 시스템과의 상호 간섭 효과를 최소화하여야 만이 WCDMA TDD 시스템의 기대용량을 얻을 수 있고, 현재 사용하고 있는 cdma2000 시스템과의 상호간섭을 최소화 할 수 있다. 본 논문에서는 3GPP TR 25.942 를 토대로 보다 정확한 파라미터를 사용하고, 시스템 레벨 시뮬레이션을 통해 WCDMA TDD 시스템과 cdma2000 시스템간의 상호간섭을 다양하고 실질적인 상황 하에서 해석하고, 또한 링크레벨을 고려한 시스템 레벨 시뮬레이션 결과로부터 두 시스템간의 상호간섭을 분석한다. 시뮬레이션 결과로부터 WCDMA TDD 시스템과 cdma2000 시스템 간 상호간섭을 고려한 시스템 용량의 최적화를 위한 조건을 제시한다.

• 전자공학회논문지A
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• 제33A권6호
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• pp.220-229
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• 1996

We presetn sytem-level simulation methodology as well as environment setup established for CDMA digtial cellular mobile station in an effort to verify CDMA modem ASIC design. To make the system-level simulation feasible, behavioral modeling of a microcontroller was first carried out with VHDL. In addition, models written in C language were also developed to provide ASIC with realistic input data. Finally, the netlist of CDMA modem ASIC was loaded on the a hardware accelerator, which was interfaced with VHDL simulator, and ismulation was performed by excuting the actual CDMA call processing software. Simulation resutls thus obtained were confirmed by comparing them with the emulation resutls from the actual system constructed on hardware modeler. these methods were proved to be effective in both discovering in advance malfunctions when embedded in the system or design errors of ASIC and reducing simulation time by a factor of as much as 20 in case of simulation at gate-level.

• Nuclear Engineering and Technology
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• 제42권4호
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• pp.460-467
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• 2010

In this study, the parameters of the feedwater control system (FWCS) of the OPR1000 type nuclear power plant (NPP) are optimized by response surface methodology (RSM) in order to acquire better level control performance from the FWCS. The objective of the optimization is to minimize the steam generator (SG) water level deviation from the reference level during transients. The objective functions for this optimization are relationships between the SG level deviation and the parameters of the FWCS. However, in this case of FWCS parameter optimization, the objective functions are not available in the form of analytic equations and the responses (the SG level at plant transients) to inputs (FWCS parameters) can be evaluated by computer simulations only. Classical optimization methods cannot be used because the objective function value cannot be calculated directely. Therefore, the simulation optimization methodology is used and the RSM is adopted as the simulation optimization algorithm. Objective functions are evaluated with several typical transients in NPPs using a system simulation computer code that has been utilized for the system performance analysis of actual NPPs. The results show that the optimized parameters have better SG level control performance. The degree of the SG level deviation from the reference level during transients is minimized and consequently the control performance of the FWCS is remarkably improved.

• 대한전자공학회논문지TC
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• 제46권4호
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• pp.77-85
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• 2009

본 논문에서는 다중 셀 환경에서 MIMO-OFDM 기반 시스템을 위한 효율적인 시스템 레벨 시뮬레이션 방법을 제안한다. 실제 시스템에서 셀의 구조, 라디오 채널의 특성, 사용자의 이동성이 미치는 영향에 대해 분석하며, 특별히 사용자의 이동성에 따른 시스템레벨에서의 성능영향을 채널이득과 이동거리, 두 가지 측면에서 모두 고려한다. 다양한 시스템 환경에 따른 영향을 MIMD-OFDM 구조를 가지는 시스템에 적용하여 수신 SINR을 구하는 과정을 제시한다. 링크레벨 시뮬레이션을 통하여 얻은 수신 SNR에 대한 성능곡선을 기초로 하여, 시스템 환경의 변화에 따른 확장이 용이하고 시뮬레이션 복잡도가 낮은 시스템 레벨 시뮬레이션 방법을 제안한다. 다양한 모바일 셀룰러 환경 파라미터에 따른 성능의 변화가 제안된 시뮬레이션을 통하여 얻어지며 그 결과는 셀 중심에 위치한 기지국과 사용자간의 거리에 따른 패킷오류율을 기반으로 분석된다.

• 한국군사과학기술학회지
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• 제9권3호
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• pp.25-32
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• 2006

Weapon systems composed of several subsystems execute various engagement missions in distributed combat environments in cooperation with a large number of subordinate/adjacent weapon systems as well as higher echelons through tactical data links. Such distributed weapon systems require distributed real-time simulation test beds to integrate and test their operational software, analyze their performance and effects of cooperated engagement, and validate their requirement specifications. These demands present significant challenges in terms of real-time constraints, time synchronization, complexity and development cost of an engagement simulation test bed, thus necessitate the use of high-performance distributed real-time simulation architectures, and modeling and simulation techniques. In this paper, in order to meet these demands, we presented a distributed real-time simulation system based on High Level Architecture(HLA) and Discrete Event System Specification(DEVS). We validated its performance by using it as a test bed for developing the Engagement Control System(ECS) of a surface-to-air missile system. The proposed technique can be employed to design a prototype or model of engagement-level distributed real-time simulation systems.

• 조명전기설비학회논문지
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• 제25권6호
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• pp.122-128
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• 2011

This paper proposes a new control scheme of lithium ion battery units based on single phase multi-level converter. In the DC/AC converter applications using battery storage system, it is necessary to control the balancing voltage of individual battery units for high efficiency utilization. Using the proposed control scheme, the DC/AC single phase converter system is applied. To verify the effectiveness of the proposed control scheme, computer simulation is accomplished. In the computer simulation, lithium-ion battery units and single phase multi-level converter system are modeled and carried out using Psim simulation program. It will be helpful for design and applications of energy storage system with lithium-ion battery.

• 한국시뮬레이션학회논문지
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• 제8권4호
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• pp.137-154
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• 1999

In this paper, we propose a software design method that will track the effects of modifications in a component to the rest of the components in the design phase. The prediction of the effects due to the design modifications before coding can be a valuable aid for the complex and large software development. Within the method, the target system is represented by the structured I/O system level specification which is one of the system representation level defined by the system theory. Then it is abstracted to the I/O system level. The DEVS (Discrete Event System Specification) model is constructed based on tile I/O system level specification. Finally, the DEVS model is simulated to generate the behavior of the software by the abstract simulator in DEVS simulation environment. As an application, the graphic user interface system of a metal grating production scheduling system is presented.