• 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.

• 전자공학회논문지A
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• 제30A권2호
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• pp.76-85
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• 1993

This paper describes the design of a technology-independent logic, function, and timing extraction system from SPICE-like network descriptions. Technology-independent extraction mechanism is provided in the form of technology files containing the rules for constructing logic gates and functional blocks. The designed system can be more effectively used in cell-based design by describing the cells to be extracted. Timing extraction is performed by using a linear RC gate delay model which takes interconnection delay into account. Experimental results show that estimated delay is within 10 percents for logic gate circuits when compared with SPICE. Through higher-level design descriptions obtained by extraction, design cycles can be considerably reduces.

• 한국의상디자인학회지
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• 제13권1호
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• pp.125-134
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• 2011

The research is a survey and analysis of female apparel preferences, and recognition of the KS sizing system for adult female garments. The practical surveys in this research are examined by total number of subjects, 200 women who are living in Seoul, South Korea. The homogeneity test using Chi-square statistics, and the analysis of frequencies and ratios of contingency tables were performed with the data which are classified by age, education level, income level and housing modalities. The findings in this study are as follows: 1. Women's preferences for purchasing female garments indicate significant differences between subjects, such as age, education level, income level and housing modalities. Moreover, the following five types of adult female garments were analyzed in this study: upper garment, lower garment, one-piece apparel, sportswear and sleepwear. The results of the preference study show an indirect understanding of the KSK 0051 classification system for subjects of the survey. Therefore the preference study can be used as a pilot study for the sizing recognition survey. 2. Women's recognition of the KSK 0051 sizing system for adult female adult garments do not indicate significant differences based on the characteristics of age, education level, income level and housing modalities. The low recognition of the KS sizing system is due to too many details and complex numbers of application for users. Therefore, the sizing system should be simplified and rearranged to be more effective and have more recognizable categories.

• 한국CDE학회논문집
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• 제16권4호
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• pp.305-313
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• 2011

This paper proposes a method for reusing kinematic design data for virtual facilities, Making a virtual model of a facility involves two major activities: geometric design (virtual model visualization) and kinematic design that should be remodeled frequently whenever design changes occur, Conventionally, a virtual model of an automated facility focuses on the design level, which mainly deals with design verification, alternative comparison, and geometric model diagnosis, Although a design level model can be designed with the information of past models from PLM system, a simulation level model is not sufficient utilized to be reused for kinematic design purpose, We propose a method for reusing kinematic information of a past simulation model to cope with this problem, We use the concept or the 'center of mass', which is a point representing the mean position of the matter in a body or system. And we also use comparison method of a boundary box to identity which 3D objects have to be involved from the design model to a link structure that is contained in the simulation model. Because a proposed method only use not a historical approach but a geometrical approach, it is more effective to apply to the field.

• Structural Engineering and Mechanics
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• 제38권4호
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• pp.429-441
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• 2011

In large-scale problem, a huge size of computational resources is needed for a reliable solution which represents the detailed description of dynamic behavior. Recently, eigenvalue reduction schemes have been considered as important technique to resolve computational resource problems. In addition, the efforts to advance an efficiency of reduction scheme leads to the development of the multi-level system condensation (MLSC) which is initially based on the two-level condensation scheme (TLCS). This scheme was proposed for approximating the lower eigenmodes which represent the global behavior of the structures through the element-level energy estimation. The MLSC combines the multi-level sub-structuring scheme with the previous TLCS for enhancement of efficiency which is related to computer memory and computing time. The present study focuses on the implementation of the MLSC on the direct time response analysis and the frequency response analysis of structural dynamic problems. For the transient time response analysis, the MLSC is combined with the Newmark's time integration scheme. Numerical examples demonstrate the efficiency of the proposed method.

• 한국시뮬레이션학회논문지
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• 제22권1호
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• pp.41-51
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• 2013

이 논문에서는 EV-DO나 브로드캐스트 멀티캐스트 서비스와 같은 CDMA 셀룰러 표준을 목표로 하는 시스템 수준 시뮬레이터의 설계 방법론을 소개한다. 셀 레이아웃, 모바일 분포, 채널 모델링, 수신 전력 계산, 스케줄링, 패킷 에러 예측, 트래픽 생성 등의 절차를 따라 가면서, 시스템 수준 시뮬레이터의 기본 구조와 시뮬레이션 흐름을 기술하였다. 시뮬레이터를 모델링하기 위해, CDMA 시스템과 EV-DO 방송 시스템의 순방향 링크에서의 패킷 데이터 전송을 고려하였다. 셀룰러 표준을 위한 시스템 수준 시뮬레이터는 상위 수준 언어로 모델링 및 개발 되었고, 용량과 커버리지를 포함한 에어 접속부 성능 지표들을 계산 및 예측하는 데에 이용되었다.

• 조명전기설비학회논문지
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• 제22권12호
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• pp.115-121
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• 2008

현재 추진되고 있는 무선통신을 기반으로 하는 열차제어시스템 개발 프로젝트에서는 상호운영성 및 상호교환성을 고려하는 하부시스템의 개발을 목표로 하고 있다. 이 프로젝트는 상위 시스템 수준의 설계보다는 주로 하부시스템의 설계에 집중되어 있다. 시스템에 대한 시험평가는 시스템 사양에 대한 만족 여부를 확인하는 것이며, 이에 따라 시스템 수준으로 통합된 시스템 사양서가 필요하다. 본 연구에서는 시스템 사양서가 마련되지 않은 하부시스템의 설계단계에서 최상위 시스템 수준의 시험평가에 대한 방안을 제시하였다.

• KIEAE Journal
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• 제17권3호
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• pp.119-124
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• 2017

Purpose: Groundwater heat pump (GWHP) system has high coefficient of performance than conventional air-source heat pump system and closed-loop type geothermal system. However, there is problem in long-term operation that groundwater raise at the diffusion well and reduced at the supply well. Therefore, it is necessary to accurately predict the groundwater flow, groundwater movement and control the groundwater level in the wells. In this research, in consideration of hydrogeological characteristic, groundwater level and groundwater movement were conducted analysis in order to develop the optimal design method of the two-well system using the pairing pipe. Method: For the optimum design of the two-well system, this research focused on the design method of the pairing pipe in the simulation model. Especially, in order to control the groundwater level in wells, pairing pipe between the supply well and diffusion well was developed and the groundwater level during the system operation was analyzed by the numerical simulation. Result: As the result of simulation, the groundwater level increased to -2.65m even in the condition of low hydraulic conductivity and high pumping flow rate. Consequently, it was found that the developed system can be operated stably.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.484-490
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• 1996

The Pressurizer Level Control System (PLCS) logic for YGN 5&6 was developed to incorporate the design changes on the Chemical and Volume Control System (CVCS). The YGN 5&6 CVCS uses the centrifugal charging pumps and letdown orifices replacing the positive displacement pumps and letdown control valves in the YGN 3&4 and UCN 3&4. The purpose of this study is to develop new PLCS as well as validate newly developed control logic and its implementation method in the simulation computer code. The analysis results show that the new PLCS has adequate ability to control the pressurizer level in response to the design bases events, and the simulation computer code is useful for YGN 5&6 NSSS design code.

• 한국국방경영분석학회지
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• 제24권1호
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• pp.176-188
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• 1998

In this paper, it is identified that the optimal level of each performance measures (service and inventory level) is not sensitive to an uncertain environment under JIT Kanban system designed by Moeeni. Moreover, it is proposed that the optimal design method considering multiple performance characteristics is the optimal level decision method according to the relative importance differences of each performance when there exist multiple performance characteristics. The result from the simulation analysis shows that the number of Kanban for stage 3 (final process) and stage 2 is increased at the service level. It is found that the expected loss is minimal when the cycle time decreases and the container size increases. However, the stage 1 is not affected by the number and cycle time of Kanban. It is thus important to consider carefully the cycle time and the container size of the Kanban to satisfy the demand in right time. In case of inventory level, the working inventory level decreases when the container size is decreased and the working inventory level also decreases slightly when the cycle time of the Kankban is increased in stage 1 and 2.