• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.51-53
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• 1993

This paper proposes a design of the tracking controller using artificial neural network and the compare the result with a result of optimal controller. In practical use, conventional Optimal controller has some limits. First, optimal controller can be designed only for linear system. Second, for many systems state observation is difficult or sometimes impossible. But the controller using artificial neural network does not need mathmatical model of the system including state observation, so it can be used for both linear and nonlinear system with no additional cost for nonlinearity. Designed multi layer neural network controller is composed of two parts, feedforward controller gives a steady state input & feedback controller gives transient input via minimizing the quadratic cost function. From the comparison of the results of the simulation of linear & nonlinear plant, the plant controlled by using neural network controller shows the trajectory similar to that of the plant controlled by an optimal controller.

• KIEAE Journal
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• 제3권3호
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• pp.11-18
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• 2003

The purpose of this study was to find out awareness of the environment-friendly planning elements for residential unit space among practitioners. The respondents in this questionnaire survey were 140 practitioners in architecture and interior design field. The major findings of this study were as follows; most of the respondents were aware of the impact of indoor built environment on residents' wellness. In addition, the survey respondents viewed that the factors for planning environment-friendly high-rise apartments were represented by gardening and energy-saving while their perception on the concept excluded comprehensive components affecting residents' life quality. Over 50% of respondents had an experience of applying environment-friendly planning elements in their works, and high frequency appeared on the general planning elements which had been applied special awareness as pro-environmental features. The respondents considered environment-friendly planning elements as important. Specially, space planning and system were considered more likely important in interior design field. In application of environment-friendly planning elements, cost, lack of consumers' awareness of and underdevelopment of environment-friendly materials were of concern. Therefore, the consumer's cognition needs to be improved for wide application about environment-friendly planning element, and then consumers are willing to pay additional construction cost of environment-friendly apartments. At the same time, the current practice that housing developers pass the additional cost on to residents needs to be changed. Then, the quality of life in high-rise residential settings can be improved. More importantly, the exchange and development of the reliable information on environment-friendly planning elements need to be made, and technical support and long-term policy for the development are required. This research showed current status of knowledge and practice in sustainable planning of unit apartment and proved basic information for future direction.

• 한국건설관리학회논문집
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• 제20권5호
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• pp.21-30
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• 2019

최근 전 세계적으로 지구온난화에 따른 이상기온과 화석연료 고갈 등 환경과 에너지문제는 인류의 생존을 위협하는 중대 과제로 대두되고 있다. 이에 따라 건축물 에너지 절감 및 온실가스 감축에 획기적으로 기여할 수 있는 혁신적인 건축물로서 제로에너지빌딩에 대한 관심이 높아지고 있다. 그러나 시장에서는 추가되는 건설비용은 제로에너지 인증 활성화에 큰 걸림돌이 되고 있다. 본 연구에서는 일반적인 민간 분양아파트를 연구의 대상으로 선정하고 초기 설계단계부터 제로에너지 인증을 위한 세부 요소들을 친환경주택 건설기준에 근거하여 제시하였으며, 인증 세부요소들의 비용효율분석을 통해 적정 가산비용을 제시하였다. 아직까지 기술수준과 물리적인 한계로 인하여 공동주택에서는 3등급까지만 인증이 구현 가능 한 것으로 분석되었다. 또한 생애주기동안 비용추이를 검토해본 결과 아직까지 제로에너지빌딩 5등급의 경우에서만 준공 후 13년 이내 모든 비용의 회수가 가능한 것으로 검토되었다. 앞으로 발주예정인 공동주택 사업 검토 시 본 연구에서 제시된 추가사업비가 적절히 반영되어 제로에너지빌딩 인증 활성화에 기여하고자 한다.

• 한국IT서비스학회지
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• 제11권1호
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• pp.1-14
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• 2012

The Web accessibility compliance rate of public organizations and private enterprises is still low due to the lack of awareness of Web accessibility by website developers and managers in spite of the fact that web accessibility compliance became mandatory in 2008. Web developers and managers think the website visual quality might be compromised or the website requires more development time and budget in order to comply with the web accessibility guidelines. Therefore, this paper has analyzed whether developers with various training in web accessibility or experience on website development have different perception on time, cost and design issues for developing accessible websites. For this purpose, 72 Web developers with hand-on experience working for website development companies in Korea were sent to the questionaries. The results have indicated that the group of developers with many hours of training in web accessibility and rich experience on website development perceives that they can develop accessible website without additional cost and time or compromising design quality. The contributions of this paper are following： (1) proving the widely recognized perception on budget, time, and design for developing accessible website is incorrect and (2) motivating further research on this subject in the future.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.651-655
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• 2004

This paper studies the designing method and application for grommets, rubber material used to absorb vibration on the air conditioner compressor. The existing grommet with hardness 40 degrees, EPDM, has the high transmissibility on the compressor that causes additional structure born sound. The problem for EPDM is transformation over long time usage possibly due to its design in which stress is concentrated on a certain position. In order to resolve it, silicon material was previously used with the same design in some models. The vibration performance did improve, but the cost became high. Below are the major developments regarding improvements in compressor rubber material, vibration performance and durability through design change, and new grommet to attain cost reduction. 1 The optimum grommet design for stress even distribution through FEM methods. 2. Comparison for grommet material and design for improved transmissibility. 3. Assess for grommets durability and product applications.

• 한국건설관리학회논문집
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• 제8권6호
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• pp.178-187
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• 2007

최근 정부의 주택보급정책 강화에 따라 공공아파트 건설공사의 건축공사비에 대한 관심이 높아지고 있다. 그러나 현재 공공아파트 공사비내역 구성은 공종별 분류체계로 구성되어 있어, 공공아파트의 건축공사비를 체계적으로 예측하는 것은 현실적으로 많은 문제점을 지니고 있다. 이에 본 연구에서는 공공아파트 프로젝트 기획 및 설계단계에서 좀 더 합리적인 공사비 예측을 위해, 델파이분석(Delphi)기법을 이용하여 공공아파트 공간별 공사비분류체계를 개발하였다. 공공아파트 공간별 공사비분류체계는 공공아파트의 공간별 특성을 반영하여 주택부문, 주택외부문, 가산부문 등으로 구분하였으며, 각각의 부문을 공간별 해당 부위와 각 세부공종으로 세분화하였다. 또한 구축된 공간별 공사비분류체계에 공공아파트 공사비 내역서를 분석하여 공간별 분류체계의 실용성 및 유효성을 검증하였다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.349-356
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• 2000

Strenght and ductility are major factors in the aseismic design of a bridge pier. In spite of good performance in both steel piers have not been used widely due to high cost. But with the filled-in concrete the steel pier have advantages compare to the steel pier only such as improved strength ductility fast construction small section and reasonable cost. In this paper concrete-filled steel piers are tested using quasi-static cyclic lateral load with constant axial load to evaluate the performance. The secondary reinforcement devices such as bolts corner plate and turn buckle are used inside of the piers to improve the ductility with minimum additional cost. Test results shows filled-in concrete and secondary reinforcement devices increase the strength and the ductility of the steel pier.

• 전자공학회논문지A
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• 제31A권6호
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• pp.177-187
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• 1994

In the design of modern computer systems, the speed gap between the CPUs and DRAMs has been a major concern. To relieve this problem at a low cost, several new DRAM architectures have been proposed. This study is aimed at evaluating quantitatively the impact of the new DRAM architectures (synchronous DRAM. dual-RAS synchronous DRAM, and enhanced DRAM) on the memory system performance. We developed a cache and memory simulator and performed various experiments using the traces generated from four benchmark programs. The simulation results show that the new DRAM architectures offer a better performance than a conventional one by 5~30% in a low cost system and their improvement in a high performance system is less than 1%. However, for resonable multiprogramming workoads, additional performance improvement of about 10~28% is expected in a high performance system while 1~3% in a low cost system.

• Korean Chemical Engineering Research
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• 제59권3호
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• pp.467-479
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• 2021

Abstract: A kinetic model was developed for the dehydration of ethanol to ethylene based on two parallel reaction pathways. Kinetic parameters were estimated by fitting experimental data of powder catalysts in a lab-scale test, and the effectiveness factor was determined using data from pellet-type catalysts in bench-scale experiments. The developed model was used to design a multitubular fixed-bed reactor (MTR) and an adiabatic reactor (AR) at a 10 ton per day scale. The two different reactor types resulted in different process configurations: the MTR consumed the ethanol completely and did not produce the reaction intermediate, diethyl ether (DEE), resulting in simple separation trains at the expense of high equipment cost for the reactor, whereas the AR required azeotropic distillation and cryogenic distillation to recycle the unreacted ethanol and to separate the undesired DEE, respectively. Quantitative analysis based on the equipment and annual energy costs showed that, despite high equipment cost of the reactor, the MTR process had the advantages of high productivity and simple separation trains, whereas the use of additional separation trains in the AR process increased both the total equipment cost and the annual energy cost per unit production rate.

• Journal of Power Electronics
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• 제15권3호
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• pp.610-620
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• 2015

An inherent zero-voltage and zero-current-switching phase-shifted full-bridge converter with reverse-blocking insulated-gate bipolar transistor (IGBT) or non-punch-through IGBT is proposed in this paper. This converter not only ensures that the switches in the lagging leg works at zero-current switching, but also minimizes circulating conduction loss without any additional auxiliary circuits. A 1.2 kW hardware prototype is designed, fabricated, and tested to verify the proposed topology. The control loop design procedures with small-signal models are also presented. A simple, low-cost, and robust democratic current-sharing circuit is also introduced and verified in this study. The proposed converter is a suitable alternative for compact, cost-effective applications with high-voltage input.