• KIEAE Journal
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• v.13 no.4
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• pp.55-62
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• 2013

Korea Government have carried out various policies to reduce the energy consumption that cause the global warming and environmental pollution. Energy consumption of buildings in Korea has reached 24% of total energy quantities and energy consumption of apartment has been continuously increasing. It has executed the building energy efficiency rating system and energy performance assessments and certification systems have been in force to save energy consumption of buildings. Therefore, this study tried to asset the energy performance of apartment according to the shapes of unit plan, and then to evaluate the energy performance of apartment according to altering balcony area into living area in the unit plan of apartment and thus, to present the effective unit plan to reduce the energy consumption. According to the results, in case of standard unit plan, the 3Bay and 4Bay unit plans showed more effective energy consumption than the 2Bay unit plan, respectively, 5%, 6%, and in case of extended unit plan, respectively, 2%, 5%. Compared the energy efficiencies of the standard unit plan to the extended unit plan, the standard one showed more effective energy consumption than the extended one, respectively, 2% in case of the 2Bay and 4Bay unit, 5% of the 3Bay unit.

• KIEAE Journal
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• v.15 no.5
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• pp.89-94
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• 2015

Purpose: Various policies to reduce the energy consumption have been carried out to save Earth environment against global warming and environmental pollution in many countries. Energy consumption of buildings in Korea has reached 24% of total energy consumption, and energy consumption of apartment has been continuously increasing. Therefore, Korea government has executed building energy efficiency rating certification system to control energy consumption of buildings. Method: This study was conducted to evaluate the energy performance of apartment unit plans according to the increasement of front width of unit plans, and tried to present the basic data to design more energy conscious unit plans for apartments. For the study, three shapes of unit plans -the 2Bay, 3Bay and 4bay unit- were selected for imput models. They were simulated using ECO2 software to assess building energy efficiency rating certification in Korea. Result: According to the results, in cases that balcony windows were not installed, the primary energy consumption of the 3Bay and 4Bay units were less than 2Bay unit, respectively, 0.1% and 2,5%. The primary energy consumption of the 3Bay and 4Bay units, in cases that balcony windows were installed, was less than 2Bay unit, respectively, 1.7% and 3.2%.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.354-362
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• 2012

Recently, High Efficiency Video Coding (HEVC) is under development jointly by MPEG and ITU-T for the next international video coding standard. Compared to the previous standards, HEVC supports variety of splitting units, such as coding unit (CU), prediction unit (PU), and transform unit (TU). Among them, it has been known that the recursive quadtree structure of CU can improve the coding efficiency while the encoding complexity is increased significantly. In this paper, a simple conditional probability to predict the early termination condition of recursive unit structure is introduced. The proposed conditional probability is estimated based on Bayes' formula from local statistics of rate-distortion costs in encoder. Experimental results show that the proposed method can reduce the total encoding time by about 32% according to the test configuration while the coding efficiency loss is 0.4%-0.5%. In addition, the encoding time can be reduced by 50% with 0.9% coding efficiency loss when the proposed method was used jointly with HM4.0 early CU termination algorithm.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.6
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• pp.971-974
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• 1987

Considering heat transfer and heat loss processes for the heat engine operating between two fixed heat reservoirs, it may be qualitatively explained that the maxima of power output and its efficiency depending upon operating conditions are extreme maxima. Furthermore, it is also found that from an economic point of view the above two extremes are related to extreme minima of plant cost per unit power output and operation cost per unit power output respectively, and the condition of minimum cost per unit power output exists between the extreme minimum conditions of plant cost per unit power output and that of operation cost per unit power output.

• Journal of Agricultural Extension & Community Development
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• v.23 no.4
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• pp.441-448
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• 2016

The study aims to explore the problems of analysis unit when examining management performance and efficiency using DEA (Data Envelopment Analysis). Generally the DEA results depend on input, output, and analysis units. We used data from Park (2012) which analyze paddy farmers in Jeonnam province. Results show that data from farm household unit was well fitted to examine management efficiency, not data from per area unit. This study will be helpful for researchers and practitioners to understand proper analysis unit when using the DEA for enhancing farm competitiveness.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.141-150
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• 2000

Continuously variable transmission(CVT) combined differential gear unit has many advantages, which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral. It is known that such CVT can be classified into the input coupled type and the output coupled type according to the coupling location of continuously variable unit(CVU). In this paper, six different configurations of input coupled type CVT combined V-belt CVU and 2K-H I type differential gear unit are proposed. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. The propriety of derived formula and theoretical analysis are proven by various experiments.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1119-1125
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• 2010

Most of the sludge pre-treatment methods to improve the anaerobic digestibility of sludge are not practied in the fields with low economical efficiency. The venturi cavitation system (VCS) adopting hydrodynamic cavitation is simple and requires low energy. This research was conducted to investigate the optimum design and operating conditions of the VCS. The experimental results indicated that the optimum number of venturi in series was three, and the suction mode operation of the pump yielded 1.6 times higher pre-treatment efficiency per unit energy consumption than the discharge mode. The combination of venturies with different throat sizes did not affect the pre-treatment efficiency. Also, the parallel installation of the three in series venture unit yielded 30% higher pre-treatment efficiency per unit energy consumption than the single unit. Under parallel conditions, the solubilization efficiency was 5.6 mg ${\Delta}SCOD/g$ TS/kWh, which is higher than the previously reported value.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.196-198
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• 2011

MPEG 과 VCEG 의 공동협력팀인 JCT-VC(Joint Collaboration Team on Video Coding)에서는 H.264/AVC 보다 두 배 이상의 높은 부호화 효율을 목표로 HEVC(High Efficiency Video Coding) 표준화를 진행하고 있다. HEVC 표준화에서는 압축 효율뿐만 아니라 부호화기의 복잡도도 중요하게 고려되고 있다. 본 논문에서는 HEVC 부호화기의 높은 복잡도를 줄이기 위하여 상위 깊이의 부호화 단위(Coding Unit: CU)의 움직임 정보를 이용하여 현재 부호화하는 예측단위(Prediction Unit: PU)의 참조영상의 후보의 수를 제한하는 고속 부호화 알고리즘을 제안한다. 모의실험을 통하여 제안한 알고리즘은 HM3.0 에 비해 평균 10.8% 정도의 부호화 시간을 감소시키며, 이때 평균 비트율은 0.5%로 부호화 효율의 감소가 미미함을 확인 하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.361-364
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• 2012

MPEG과 ITU-T에서 최근 표준화가 진행되고 있는 HEVC는 H.264/AVC에 비해, CU(coding unit), PU(prediction unit), TU(transform unit)의 다양한 형태 분할 단위를 갖는 것을 큰 특징으로 한다. 이 중, CU와 TU는 쿼드트리 형태의 재귀적 분할 구조를 가지도록 구성되는데, 압축 효율은 향상시키지만 높은 부호화 복잡도를 갖는 단점이 있다. 본 논문에서는 이러한 재귀적 분할 구조를 변환하여 가장 작은 CU의 정보를 병합하여 큰 CU의 정보를 빠르게 결정하는 방법을 제안한다. 제안한 방법을 HEVC의 CU 부호화에 적용한 결과, 부호화 복잡도를 32-45% 가량 감소시키면서 압축 효율 하락은 0.6-0.9%로 억제할 수 있었다. 또한, HM6.1에 구현되어 있는 고속 탐색 알고리즘과 비교 할 경우, 압축 효율 하락을 0.2-0.3%로 억제하면서 부호화 복잡도를 8-12% 감소시킬 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1611-1614
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• 2002

하나의 보드에 대한 소자들의 테스팅을 위해서 IEEE 1149.1이 제안되었고 완전한 테스팅을 지원한다. 하지만 여러 보드에 대해서는 불가능하여 IEEE 1149.1을 확장한 시스템 레벨의 테스팅 방법이 제안되었다. 기존의 IEEE 1149.1을 확장한 방법은 보드 레벨의 테스팅과 시스템 레벨의 테스팅이 하나의 데이터 패스에 의해서 테스트 시간이 길고 비효율적이다. 본 논문에서는 보드 레벨 테스팅과 시스템 레벨 테스팅을 구분하여 불필요한 테스트 데이터 이동을 줄여 테스트 시간을 줄이고 효율적인 방법을 제시한다. 그리고 이를 지원하기 위한 Path Select Unit을 설계한다. 구현된 PSU는 작은 게이트 사이즈로 적은 테스트 비용으로도 효율적으로 시스템 레벨 테스팅이 가능해진다.