• 한국통신학회논문지
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• 제19권12호
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• pp.2340-2352
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• 1994

현재 상용화중에 있는 지능망 서비스들은 그 기능이 주로 교환기내에서 수행되고, 구조자체도 조직적이지 못한 관계로 새로운 서비스의 창출이나 수정이 어려웠다. 이점을 극복하기 위하여 최근 들어 고도지능망(AIN : Advanced Intelligent Network) 구조에 관한 연구가 활발히 진행되고 있다. 본 논문에서는 이러한 현황에 발맞춰 고도지능망구조의 서비스교환기(SSP : Service Switching Point)에 대한 설계와 그에 대한 성능용량을 얻고자 한다. 즉 ITU-T 권고안을 토대로 교환기가 고도지능망서비스를 처리하기 위하여 필요한 기능들을 규정하고, 이에 따른 고도지능망 구조의 SSP를 국내의 TDX-10교환기를 토대로 설계하여, 이를 시뮬레이션 방법을 통하여 성능을 해석한다. 본 연구의 결론으로서 시스템이 기본모델을 수행할 경우, 최대 메시지 처리용량은 착신과금서비스처리시 127만 BHCA, 신용통화서비스 처리시 119만 BHCA인 것으로 판명되었고 병목요소는 INS(Inter-connection Network Subsystem) 내의 프로세서임이 밝혀졌다. 또한 시뮬레이션과 해석적 모형에 의한 방법을 통해 시스템의 성능향상을 위한 여러 방안, 즉 프로세서 처리속도의 향상 링크 속도의 향상 그리고 D-bus의 서비스정책 변경 등을 제시하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1211-1215
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• 2003

Accurate mathematical models of spacecraft components are an essential of spacecraft attitude control system design, analysis and simulation. Gyro is one of the most important spacecraft components used for attitude propagation and control. Gyro errors may seriously degrade the accuracy of the calculated spacecraft angular rate and of attitude estimates due to inherent drift and bias errors. In order to validate this model, nominal case simulation has been performed and compared for the low range mode and high range mode, respectively. In this paper, a mathematical model of gyro containing the relationships for predicting spacecraft angular rate and disturbances is proposed.

• 전자공학회논문지S
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• 제34S권7호
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• pp.9-18
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• 1997

In this paper, we implemented the communication module in the Telephone Network Access Subsystem(TNAS) of the Advanced Communications Processing System(ACPS). We defined some kinds of communication tasks and related resources like several queues which are executed in real-time operating system, and implemented the procedures for processing the user information. Through traffic modeling and simulation, the performance of the Service Processing board Assembly(SPA) is evaluated in the aspets of system utilization and buffer size. The ACPS should accommodate various public networks such as public switch telephone network, packet switchen data network, frame realy netork, and ATM network. The communications module proposed in this paper could be used inthe interface beween the SPA and the High Speed Network Adaptor of other network interface subsystems.

• The Journal of the Acoustical Society of Korea
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• 제15권2E호
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• pp.50-59
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• 1996

In this paper, an adaptive precompensator, which can reduce the distortion of a Wiener system effectively, is proposed. The previous techniques for adaptive precompensation, based on the Volterra series modeling to compensate the distortion of a nonlinear system, are not suitable for real-time implementation due to high computational burden and slow convergence burden and slow convergence rate. This paper presents an adaptive precompensation technique for the class of nonlinear subsystem, referred to as Wiener system. An adaptive algorithm for adjusting the parameters of a precompensator, structured by a hammerstein model, is derived using the stochastic gradient method. Also, an adaptive precompensatin technique which can effectively reduce nonlinear distortion in μ-law type of saturation characteristics is proposed. The validity of the proposed algorithm is confirmed through simulation by applying it to known Wiener systmes and a typical loudspeaker model.

• 한국통신학회논문지
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• 제22권11호
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• pp.2521-2530
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• 1997

In this paepr, we present a video-on-demand (VOD) system design model that address and integrates a number of inter-related issues. Then with analysis and performance evaluation, we investigate various aspects of disk and buffer managements in the given model. Based on the analysis results, we suggest that a distributed buffering scheme with intermediate buffers may te useful to transform bursty disk accesses into a continuous stream for for glitch-free performance of VOD systems. Also, through simulation, we illustrate that massive multimedia information storage design techniques such as prefetching, clustered striping, and real-time disk scheduling integrated with the distributed buffering mechanism may enhance end-to-end real-time performance of VOD systems under wide-area networks.

• 한국지능시스템학회논문지
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• 제7권2호
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• pp.110-121
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• 1997

Stability issues of linear Takagi-Sugeno fuzzy modles are thoroughly investigated. At first, a systematic way of searching for a common symmetric positive definite P matrix (common P matrix in short), which is related to stability, is proposed for N subsystems which are under a pairwise commutativity assumption. Robustness issue under modeling uncertainty in each subsystem is then considered by proposing a quadratic stability criterion and a method of determining uncertainty bounds. Finally, it is shown that the pairwise commutative assumption can be in fact relaxed by interpreting the uncertainties as mismatch parts of non-commutative system matrices. Several examples show the validity of the proposed methods.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.165-170
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• 1992

In this paper, the Hardware-In-The-Loop Simulation(HILS) of missile systems are studied. The HILS is an effective performance evaluation technique that bridges the simulation fidelity gap between analytic all-digital simulations and actual flight tests of missile systems. The HILS may be required to perform system integration tests, performance evaluation at system or subsystem level. Major elements of this HILS facility will include the flight table, simulation computers, I/O computer and peripheral equipments. HILS of missile systems typically involve computer modeling of flight dynamics coupled with a hardware guidance and control(G/C) systems. This paper describes a real time performance evaluation technique of a G/C system, Development of a HILS for a Autopilot of SAM G/C will be used as an example.

• 산업경영시스템학회지
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• 제17권32호
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• pp.227-232
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• 1994

In the performance domain, physical performance is a measure that represents some degree of system, subsystem, component or device success in a continuous sense, as opposed to a classical binomial sense (success or failure). If applicable sensing and monitoring means exist, physical performance can be observed over time, along with explanatory variables or covariables. Performance-based reliability represents the probability that performance will remain satisfactory over a finite period of time or usage cycles in the future when a performance critical limit (which represents an appropriate definition of failure in terms of performance) is set at a fixed level, based on application requirements. In the case of inadequate knowledge of the failure mechanics, this physical based empirical modeling concept along with performance degradation knowledge can serve as an important analysis tool in reliability work in product and process improvement.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.509-513
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• 1996

The information technology of computers and computer tools have become so powerful that virtual enterprises are not just concepts any longer The virtual enterprises comprise distributed facilities and it is necessary to have a collaborative system among them. This paper proposes the modeling process of web-based collaborative system in the distributed manufacturing environment. It also presents the information infrastructure in order to communicate and to share the information more efficiently among the collaboration subsystem. The web-based collaborative system consists of four processes: 1) product design, 2) procurement of DB information, 3) query process, and 4) negotiation. The proposed web-based collaborative system will be implemented with network technologies.

• 한국전자거래학회지
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• 제5권2호
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• pp.81-99
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• 2000

Nowadays, many commercial ERP products, such as Oracle, SAP, and Baan, etc, are designed based on large-scaled companies. It is difficult for small and medium-size companies with weakness in budgets and resources(e.g., human, organization, technique, and so on) to use them as it was. So, new ERP system need to be provided for small and medium-size companies. In this paper, we model and provide a conceptual ERP model for small and medium-size companies by using "4＋1 View" architecture model of Unified Modeling Language(UML). The conceptual ERP model consists of five subsystems： Manufacturing, Sales, HumanResource and Payroll, Accounting, and Trading. Especially, we describe the conceptual ERP model focusing on "Manufacturing" subsystem by using several diagrams of UML. By using the conceptual ERP model, the ERP system′s developers of small and medium-size companies can obtain many benefits： improving the efficiency of software developing process and helping user requirements gathering and description of ERP system′s nonfunctional aspect as well as functional aspect.