• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 1999년도 제1회 학술대회논문집(KIASC 1st conference 99)
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• pp.18-21
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• 1999

The effects of joining process such as contact method, shape of joined area and pressure on the properties of Bi-2223 superconducting tape have been optimized. In the process tapes were etched to expose the superconductor core in the shape of 'ㅁ' and 'ㄷ'. The exposed cores of the two tapes were brought into contact, uniaxially pressed and sintered. Subsequently, the current capacity of the joined tape was measured as a function of uniaxial pressure. It was observed that the current capacity was significantly dependent on uniaxial pressure. The joined tape, fabricated with a pressure of 1,600 MPa, showed the highest value of current capacity(90%) of highest value of current capacity is resulted from improvements in core density, contacting area and grain alignment, etc. In addition the effect of processing variables on microstructural evolution and mechanical property of joined tape will be presented.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.249-258
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• 1999

Dynamic load and static load tests are performed on steel pipe piles and concrete piles at five construction sites in highway to compare the difference of load bearing mechanisms. At each site, one steel pile is instrumented with electric strain gages and dynamic tests are performed on the pile during installation. Damages of strain gages due to the installation are checked and static test is performed upon the same pile after two or seven days as well. It shows that load transfer from side friction to base resistance behaves somewhat differently according to the results of load-settlement analysis obtained from PDA and static load test. Initial elastic stage of load settlement curves of two load tests is almost similar. But after the yielding point, dynamic resistance of pile behaves more stiffer than static resistance, thus, dynamic load test result might overestimate the real pile capacity compared with static result. Analysis of gage readings shows that unit skin friction increases exponentially with depth. The skin friction is mobilized at the 1∼2m above the pile tip and contributes to the considerable side resistance. Comparison of side and base resistances between the measured value and the calculated value by Meyerhof's bearing capacity equation using SPT N value shows that the calculated base resistance is higher than the measured. Therefore, contribution of side resistance to total capacity shouldn't be ignored or underestimated. Finally, based upon the overall test results, a construction control procedure is suggested.

• 설비공학논문집
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• 제14권9호
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• pp.749-755
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• 2002

In order to develop a multi-type heat pump system with two indoor units of non-uniform capacities, the optimum refrigerant circuit was developed using capillary tubes. The refrigerant circuit was composed of four main parts, a heating circuit, a cooling circuit, a by-pass circuit and a balance circuit. The system characteristics of multi-type heat pump was investigated through the rating test and the reliability test, using the multi-type psy-chrometric calorimeter. The results of the rating test showed that the capacity of the multi-type heat pump was about 93% of the design value. In particular, the capacity of cooling single mode was about 13% higher than the design value, and the capacity of heating multi mode was about 5% higher than the design value. The reliability of the multi-type heat pump was verified by various reliability tests (overload, extension tube, freeze up, under/over charging, sweat, flood back). The optimal amount of refrigerant charge and compressor capacity were determined from the present work.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2011년도 하계학술대회
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• pp.137-140
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• 2011

A precoding strategy is one of the representative interference management techniques in cognitive radio (CR) network which is a typical interference-limited environment. The interference minimization approach to precoding is an appropriate scheme to mitigate the interference efficiently while it may cause the capacity loss of the desired channel. The precoding scheme for the maximal capacity of the desired channel improves the capacity of the desired channel while it increases the interference power and finally causes the capacity loss of the interfered users. Therefore, we propose a precoding scheme which satisfies these two conflicting goals and manages the interference signal in such an interference-limited environment. The proposed scheme consists of two steps. First, the precoder nulls out the largest singular value of the interference channel to mitigate the dominant interference signal based on the interference minimization approach. Second, the transmitter calculates the sum capacities per mode and selects a mode to maximize the sum capacity. In the second step, each mode consists of the right singular vectors corresponding to the singular values except the largest singular value eliminated in the first step. Simulation results show that the proposed precoding scheme not only efficiently mitigate the interference signal, but also has the best performance in terms of the sum capacity in a MIMO-based CR network.

• 한국강구조학회 논문집
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• 제9권1호통권30호
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• pp.121-128
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• 1997

It has been reported by the existing papers that the ultimate load capacity and energy absorption capacity of the CFST column are considerably higher than those resulting from a simple addition of the capacities of the concrete and the steel tube. It is normally believed that the confined effect for the infilled concrete due to the hoop tension of steel at the parameter of cross sections can remarkably improve the ductility and energy absorption capacities of the CFST columns. This paper provides the results of a study on the load-carrying capacities and energy absorption capacities of the CFST columns, a numerical analysis method, i. e. N-M interaction curves and Moment curvature relationships. The numerical approaches are verified by comparing with the existing test results and the circular and square steel tube sections are selected to clarify the amount of confinement effects to improve the ultimate deformable capacity(a ultimate strain value) of the infilled concrete. Then, an adequate value of the ultimate strain of the infilled concrete and an equation of the ultimate capacity of the CFST column are suggested.

• 한국항해항만학회지
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• 제26권2호
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• pp.161-166
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• 2002

컨테이너 처리량(CHC)은 항만의 능력을 나타내는 중요한 지표다. 그러나 중국항만의 컨테이너 처리능력에 대한 연구는 부족하며, 연구결과 또한 예측치와 실제치와의 차이가 크다. 이는 컨테이너처리량이 다양한 경제적인 측면을 내포하고 있고 예측모델의 선택이 매우 어렵다는데 기인한다. 대체로 지금까지 사용되어왔던 회귀분석, 신경망분석 등은 과거행태모델을 벗어나지 못하고 있어 경제체제나 항만물동량의 동태적변화에 대한 고려가 결여되어 있다. 따라서 본 논문에서는 동태적 보정인과모델을 사용한 동태적 예측법을 사용해 보았고 그 결과 보다 신뢰성이 높고 현실성이 있는 연구결과를 도출할 수 있었다.

• Geomechanics and Engineering
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• 제30권2호
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• pp.123-138
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• 2022

Present study computes the ultimate bearing capacity of an embedded strip footing situated on the rock slope subjected to seismic loading. Influences of embedment depth of strip footing, horizontal seismic acceleration coefficient, rock slope angle, Geological Strength Index, normalized uniaxial compressive strength of rock mass, disturbance factor, and Hoek-Brown material constant are studied in detail. To perform the analysis, the lower bound finite element limit analysis method in combination with the semidefinite programming is utilized. From the results of the present study, it can be found that the magnitude of the bearing capacity factor reduces quite substantially with an increment in the seismic loading. In addition, with the increment in slope angle, further reduction in the value of the bearing capacity factor is observed. On the other hand, with an increment in the embedment depth, an increment in the value of the bearing capacity factor is found. Stress contours are presented to describe the combined failure mechanism of the footing-rock slope system in the presence of static as well as seismic loadings for the different embedment depths.

• 한국유기농업학회지
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• 제17권3호
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• pp.347-356
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• 2009

본 실험은 중부 지방에서 유기질 비료를 시용하여 두과 사료작물 초종의 생산성, 사료가치 및 가축사육능력을 조사하였고 그 결과를 요약하면 다음과 같다. 두과 사료작물의 생초 수량과 건물수량은 초종 간 차이가 인정되었으며 공시 초종 중에서 red clover가 생초수량 38.6 ton/ha, 건물수량 7.8 ton/ha, CP수량 1.0 ton/ha, TDN수량 4.6 ton/ha로 다른 초종보다 유의하게 많았다(p<0.05). NDF와 ADF는 수확시기가 늦을수록 높은 경향을 나타내서 galega와 cicer milkvetch가 가장 높았고 yellow suckling clover가 가장 낮았다. 상대사료가치(RFV)는 galega와 cicer milkvetch를 제외한 나머지 품종이 100 이상의 값을 나타내어 우수하였으며 특히, yellow suckling clover, yellow blossom sweet clover, crimson clover, hairy vetch 등은 151 이상으로 1등급에 속하였다. 가축사육능력은 초종 평균으로 Kcp(2.18 head/ha/yr) > KTDN(1.25 head/ha/yr) > K(0.04 head/ha/yr) 순으로 높았고, 초종별로는 red clover가 K 0.05 head/ha/yr, Kcp 6.84 head/ha/yr, KTDN 3.64 head/ha/yr로 공시작물 중 가장 높은 가축사육능력을 나타내었다. 이상의 결과로 볼 때 두과 사료작물 중에서 red clover가 생산성, 사료가치 및 가축사육능력이 가장 우수하여 중부지방에서 두과 사료작물 생산에 있어서 적절한 초종으로 판단되었다.

• 대한전자공학회논문지TC
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• 제49권8호
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• pp.77-83
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• 2012

본 논문에서는 주파수 공유 시스템의 구 채널 환경(outdated channel environment)에서 일차 사용자(primary user)에 의한 간섭이 존재할 때 이차 사용자(secondary user)의 평균값 기반 전력 할당 기법의 성능을 분석하고, 평가한다. 일차 사용자의 신호가 이차 사용자의 수신단에서 간섭으로 작용할 때, 이차 사용자의 에르고딕 용량(ergodic capacity)의 상한값을 분석하고, 이를 기반으로 일차 사용자에 의한 간섭이 이차 사용자의 성능 저하에 어느 정도 영향을 끼치는지 고찰한다. 모의 실험을 통해 간섭에 의한 이차 사용자의 성능 저하 정도를 보이고, 일차 사용자에 의한 간섭이 커질수록, 평균값 기반 전력 할당 기법의 용량이 구 채널 정보 기반 전력 할당 기법의 용량보다 좋아지는 영역이 작아지는 것을 보여준다.

• 한국식품과학회지
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• 제39권4호
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• pp.406-411
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• 2007

흑미가루 첨가비율(5-30%)에 따른 복합분의 이화학적 특성, 호화특성, mixograph 특성 및 스펀지 케이크의 제조적성을 측정하고, 이들 특성 간의 상관관계를 구명하고자 일련의 실험을 실시하였다. 흑미 가루 첨가량이 증가함에 따라서 alkaline water retention capacity, Pelshenke value, sedimentation value는 증가하였으나 water holding capacity는 감소하는 경향을 보였다. Mixograph peak time, height, width at peak와 Rapid Visco Analyser peak, minimum viscosity도 감소하였다. 스펀지 케이크 반죽의 pH와 비중은 증가하였지만 케이크의 부피는 감소하는 경향을 보였으며, 케이크의 경도는 증가하였다.