• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.283-285
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• 2002

조합 경매는 구매자들이 원하는 상품들을 조합해서 입찰할 수 있는 경매다. 그러나 판매자의 이익을 최대로 하는 승자를 결정하는 문제는 NP-complete이다. 분기 한정법(branch and bound)을 사용해서 최적의 승자를 찾을 때, 어떤 비드(bid)를 선택해서 분기할 것인가를 결정해야 한다. 이 때, 비드를 선택하는 휴리스틱이 분기 한정법의 성능을 결정하는 중요한 역할을 한다. 본 논문에서는 조합경매의 승자를 결정하기 위해서 분기 한정법과 Linear Programming을 사용할 때, 분기할 비드와 충돌하는 비드들을 동시에 고려하는 비드 선택 휴리스틱을 제안한다. 실험을 통해서 제시하는 휴리스틱의 성능이 우수함을 보였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.496-499
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• 2009

본 논문은 기하학적 비선형성을 가진 보존적 단일 하중 매개변수의 탄성 상태 공간구조의 분기이론에 관한 수치 해석적 기본 방법 및 경로 추적, pin-pointing, 경로 전환을 기술하고 있다. 비선형 탄성 불안정 상태는 극한점과 분기점으로 분류될 수 있으며, 평형경로상의 평형점의 계산 및 평형경로상의 특이점을 찾기 위한 pin-pointing 반복계산을 수행하는 일반적인 비선형 수치해석법으로 극한점을 계산할 수 있다. 그러나 분기좌굴 해석을 위해서는 좌굴 후 분기경로의 추적을 위한 분기경로 전환 알고리즘이 추가적으로 필요하다. 본문에서는 에너지이론에 기초한 일반 탄성안정이론을 소개하고, 평형경로 추적, 분기 좌굴점을 찾기 위한 직접법과 분기경로 전환에 관한 이론을 전개한다. 분기좌굴 해석예제로 트러스로 이루어진 스타돔, 핀지지의 평면아치, 평면프레임, 3차원 공간프레임의 분기좌굴 해석을 수행하여 본문에서 제시한 수치해석법의 정확성 및 실용성을 검증한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1993.10b
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• pp.11-30
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• 1993

종래부터 CATV 또는 MATV시스템의 신호분기회로로 사용되어 오고 있는 Tap-off는 단지 실험적 경험적으로 제작되어 왔으며 이론적인 해석이나 엄밀한 설계법이 확립되어있지 않았기 때문에 그 성능에 있어서도 대역폭이 좁거나 분기 특성이 나쁜문제점등이 있었다 따라서 본 논문에서는 보조변성기가 부가된 변형된 약결합성 신호분기기를 제안하여 설계의 자유도를 높힘으로써 상당히 조밀한 결합간격의 회로구성이 가능한 설계법을 제안하고 그 주파수특성을 계산하여 제안한 변형된 신호분기기의 설계법의 유효함을 확인하였다.

• Proceedings of the Korean Association for Survey Research Conference
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• 2001.04a
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• pp.131-152
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• 2001

In this Era of Information and Localization, Gross Regional Domestic Product(GRDP) is recognized as indispensable informatin to establish regional economic policy. Especially, to raise Chungbuk provinece´s economical independence and to establish effectual regional economic development plans. Chungbuk province needs quarterly estimated GRDP for developing regional economic forecasting system. In this study, utilizing small area estimation is proposed to estimate the quarterly Chungbuk-GRDP provided by the Bureau of Statistics and nation´s GDP provid by the Bank of Korea exists. Moreover, from the nation´s quarterly GDP in each section of economical activity, this study has presumed the quarterly comovement, applied it to subdivide Chungbuk annual GRDP quarterly, and estimated quarterly Chungbuk-GRDP.

• Survey Research
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• v.2 no.2
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• pp.131-152
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• 2001

In this Era of Information and Localization. Gross Regional Domestic Product(GRDP) is recognized as indispensable information to establish regional economic policy. Especially, to raise Chungbuk province's economical independence and to establish effectual regional economic development plans, Chungbuk province needs quarterly estimated GRDP for developing regional economic forecasting system. In this study. utilizing small area estimation is proposed to estimate the quarterly Chungbuk-GRDP. To estimate quarterly GRDP. this study assumes that the comovement between the annual Chungbuk-GRDP provided by the Bureau of Statistics and nation's GDP provided by the Bank of Korea exists. Moreover, from the nation's quarterly GDP in each section of economical activity, this study has presumed the quarterly comovement. applied ft to subdivide Chungbuk annual GRDP quarterly, and estimated quarterly Chungbuk-GRDP.

• Proceedings of the Korean Association for Survey Research Conference
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• 2001.11a
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• pp.47-64
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• 2001

In this Era of Information and Localization, GRDP is recognized as indispensable information to establish regional economic policy. Especially, to raise Chungbuk province's economical independence and to establish effectual regional economic development plans, Chungbuk province needs quarterly estimated GRDP for developing regional economic forecasting system. In this study, utilizing small area estimation is proposed to estimate the quarterly Chungbuk-GRDP. To estimate quarterly GRDP, this study assumes that the comovement between the annual Chungbuk-GRDP provided by the Bureau of Statistics and nation's GDP provided by the Bank of Korea exists. Moreover, from the nation's quarterly GDP in each section of economical activity, this study has presumed the quarterly comovement, applied it to subdivide Chungbuk annual GRDP quarterly, and estimated quarterly Chungbuk-GRDP.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.5
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• pp.297-305
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• 2006

Trace-driven simulation is widely used for measuring the performance of a microprocessor in its initial design phase. However, since it requires much time and disk space, the statistical simulation has been studied as an alternative method. In this paper, statistical simulations are performed for a high performance superscalar microprocessor with a perceptron-based multiple branch predictor. For the verification, various hardware configurations are simulated using SPEC2000 benchmarks programs as input. As a result, we show that the statistical simulation is quite accurate and time saving for the evaluation of microprocessor architectures with multiple branch prediction.

• Journal of Korean Society of Steel Construction
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• v.21 no.6
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• pp.563-574
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• 2009

This paper briefly describes the fundamental strategies--path-tracing, pin-pointing, and path-switching--in the computational elastic bifurcation theory of geometrically non-linear single-load-parameter conservative elastic spatial structures. The stability points in the non-linear elasticity may be classified into limit points and bifurcation points. For the limit points, the path tracing scheme that successively computes the regular equilibrium points on the equilibrium path, and the pinpointing scheme that precisely locates the singular equilibrium points were sufficient for the computational stability analysis. For the bifurcation points, however, a specific procedure for path-switching was also necessary to detect the branching paths to be traced in the post-buckling region. After the introduction, a general theory of elastic stability based on the energy concept was given. Then path tracing, an indirect method of detecting multiple bifurcation points, and path switching strategies were described. Next, some numerical examples of bifurcation analysis were carried out for a trussed stardome, and a pin-supported plane circular arch was described. Finally, concluding remarks were given.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.9
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• pp.477-486
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• 2003

In combinatorial auctions buyers nay bid for arbitrary combinations of goods. But determining the winners of combinatorial auctions who maximize the profit of a seller is known to be NP-complete. A branch-and-bound method can be one of practical algorithm for winner determination. However, bid selection heuristics play a very important role in the efficiency of a branch-and-bound method. In this paper, we designed and implemented an algorithm which used a branch-and-bound method and Linear Programming for winner determination in combinatorial auctions. We propose new bid selection heuristics which consider a branching bid and conflicting bids simultaneously to select a branching bid in the algorithm. In addition, upper bounds are reused to reduce the running time in specific cases. We evaluated the performance of the algorithm by experiments with five data distributions and compared our method with others. The algorithm using heuristics showed a superior efficiency in two data distributions and a similar efficiency in three distributions.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.3
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• pp.399-409
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• 1998

In this paper, the broad-band design theory for weakly-coupled Tap-Off for CATV systems has been described and the transmission line impedance matching method has been proposed. The fabricated weakly-coupled Tap-Offs based on the above theory and method have been much improved in the frequency characteristics compared with conventional ones. Thus, the useful bandwidth of weakly-coupled Tap-Offs have been extended from 5 to 2000 MHz. It is also recognized that turn numbers of the coils composing the transformer are not integers but 0.9, 1, 1.9, 2, 2.9, etc., in the actual circuits. Further, the practical measurements of the frequency characteristics for a fabricated weakly-coupled Tap-Off show very good agreements with theoretical results, and hence, the validity of the proposed design theory and transmission line impedance matching method have been confirmed.