• 경영과학
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• 제11권3호
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• pp.55-65
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• 1994

Given the flow matrix, plant size and department sizes, the algorithms in this paper provide the layout with rectilinear distance. To construct automated facility design, cut tree approach is employed. A branch and bound computer code developed by Tillinghast is modifided to find the feasible fits of departments without shape distortion in the plant rectangle.

• KIEE International Transactions on Power Engineering
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• 제2A권3호
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• pp.121-128
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• 2002

This study proposes a new method for transmission system expansion planning using fuzzy integer programming. It presents stepwise cost characteristics analysis which is a practical condition of an actual system. A branch and bound method which includes the network flow method and the maximum flow - minimum cut set theorem has been used in order to carry out the stepwise cost characteristics analysis. Uncertainties of the permissibility of the construction cost and the lenient reserve rate and load forecasting of expansion planning have been included and also processed using the fuzzy set theory in this study. In order to carry out the latter analysis, the solving procedure is illustrated in detail by the branch and bound method which includes the network flow method and maximum flow-minimum cut set theorem. Finally, case studies on the 21- bus test system show that the algorithm proposed is efficiently applicable to the practical expansion planning of transmission systems in the future.

• 한국산업보건학회지
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• 제17권3호
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• pp.203-211
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• 2007

This study was conducted in cut rose cultivation field in Goyang to evaluate pesticide exposure of farmers and the relationship between the exposure and work environment/method for cut rose farmers. Dermal exposure was assessed with patch (thin chromatography layer paper), cotton glove by body parts during mixing and spraying works in which pyrethroid, organophosphate, carbamate pesticide were used in 4 cut rose greenhouses located in Goyang province, checking characteristics of environment/working method at the same time. Body parts assessed were as follows ; glove : hand, patch : head, neck(front/back), chest, back, shoulder(right/left), upperarm(right/left), forearm(right/left), thigh(right/left), shin(right/left). Pesticides were analyzed using gas chromatography(NPD/FID) after extracting with ethyl acetate. Exposure amount differed according to pesticide type. But after standardizing with total net weight of pesticide sprayed, there were no significant difference among pesticides. There were significant difference in exposure amount among body parts(especially exposure amount of thigh, shin were more than the others), which means exposure happen not by pesticide dispersion in air but by contact with cut rose(leaf, branch) indirectly. Walking forward during spraying made farmers more exposed than waling backward, these results means contacts with leaves/branches made exposure happen in cut rose greenhouse also. As a result, pesticide exposure in cut rose greenhouse was related with contact of leaf/branch which pesticide remained in, which made exposure pattern (especially exposure amount) differ by body parts

• 산업경영시스템학회지
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• 제26권3호
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• pp.58-66
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• 2003

The cut tree approach of Montreuil and Ratliff [16] and eigenvector approach [10] are used to automatically draw a feasible facility layout with aisle structure. The department arrangement can minimize an aisle distance criterion considering door locations and dimension constraints. The aisle distance is measured by the door to door distance between departments. An eigenvector and cut tree approaches [1] are implemented based on the branch and bound technique in Kim et al. [2] in order to obtain feasible layouts. Then, the algorithm to fix the door location of each department is developed. After the door locations are determined, the factory layout is evaluated in terms of aisle distance. The aisle structure is obtained by expanding the original layout. The solution is kept until we will find better factory layout. The proposed approach based on the branch and bound technique, in theory, will provide the optimal solution. If the runs are time and/or node limited, the proposed method is a strong heuristic. The technique is made further practical by the fact that the solution is constrained such that the rectangular shape dimensions length(l) and width(w) are fixed and a perfect fit is generated if a fit is possible.

• 한국항해항만학회지
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• 제30권7호
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• pp.561-566
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• 2006

In this paper, we propose a new ship scheduling set packing model considering limited risk or variance. The set packing model is used in many applications, such as vehicle routing, crew scheduling, ship scheduling, cutting stock and so on. As long as the ship scheduling is concerned, there exits many unknown external factors such as machine breakdown, climate change and transportation cost fluctuation. However, existing ship scheduling models have not considered those factors apparently. We use a quadratic set packing model to limit the variance of expected cost of ship scheduling problems under stochastic spot rates. Set problems are NP-complete, and additional quadratic constraint makes the problems much harder. We implement Kelley's cutting plane method to replace the hard quadratic constraint by many linear constrains and use branch-and-bound algorithm to get the optimal integral solution. Some meaningful computational results and comments are provided.

• 한국CDE학회논문집
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• 제2권1호
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• pp.19-27
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• 1997

This paper presents rough cut tool path planning for the fewer-axis machine consisting of a three-axis CNC machine and a rotary indexing table. In the problem dealt with in this paper, the tool orientation is "intermediately" changed, distinguished from the conventional problem where the tool orientation is assumed to be fixed. The developed rough cut path planning algorithm tries to minimize the number of tool orientation (setup) changes together with tool changes and the machining time for the rough cut by the four procedures: a) decomposition of the machining area based on the possibility of tool interference (via convex hull operation), b) determination of the optimal tool size and orientation (via network graph theory and branch-and bound algorithm), c) generation of tool path for the tool and orientation (based on zig-zag pattern), and d) feedrate adjustment to maintain the cutting force at an operation level (based on average cutting force). The developed algorithms are validated via computer simulations, and can be also used in pure fiveaxis machining environment without modification.

• 한국통신학회논문지
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• 제18권8호
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• pp.1108-1116
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• 1993

두개의 다른 결합길이를 갖는 Y분기 방향성 결합기 광스위치를 z-cut LiNbO3로 제작하였고, r = 1.3rm에서 체스트하였다. 소자와 결합길이를 계산하기 위하여 정상모드 이론과 결합모드 이론을 사용하였다. 망전송 이론의 전산모의를 통하여 소자의 결합길이를 재 확인하였다. 직류동작시 실험 결과치들이 결합모드 이론에 의한 예측치와 잘 부합 하였다.

• 전기의세계
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• 제17권4호
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• pp.18-27
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• 1968

Analysis of the transient stability of power systems following disturbances involves many sets of non-linear differential equations. This paper attempts to analyze the transient stability of multi-machine power systems by the step by step method, using the electronic digital computer. The critical switching times and phase angles for the main 154KV transmission system in Korea, are given from the swing curves of the probable conditions. It is concluded that the system is, in general, stable if the relay is cut off within 12 cycles after the fault. However the fault of DAEGU-SANGJU branch, accompanying much real power, makes the system unstable when the raly is cut off within 4 cycles after fault or automatic voltage regulators are equipped in this branch.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.219-221
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• 1990

Y-branch directional coupler type optical modulators with three different coupling lengths were fabricated on z-cut LiNbO3 and tested at λ-1.3${\mu}{\textrm}{m}$. One device gad an exact coupling length for complete power transfer and two other devices had coupling lengths. It was confirmed that, for dc operation, experimental results agreed well with theoretical results.

• 디지털콘텐츠학회 논문지
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• 제3권2호
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• pp.221-233
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• 2002

본 논문에서는 용량제약이 있는 설비의 위치선정 및 수요자 할당 문제(Capacitated Facility Location-Allocation Problem)에 대한 정수계획 모형과 해법을 제시하였다. 이 문제는 설비를 설치할 수 있는 후보지의 집합과 각 후보지별로 설치 가능한 설비의 용량 및 설치비용, 수요를 만족시켜야 할 수요자의 집합 및 각 수요자와 설치 후보지 사이의 운반비용이 주어져 있을 때, 설비들의 설치비용과 수요의 운반비용의 합을 최소화하는 설비의 설치 위치 및 대수 그리고 수요자와 설비간의 연결상태를 구성하는 문제이다. 본 논문에서는 이 문제에 대한 두 가지 정수계획모형을 제시하고, 이 모형에 대한 최적해를 구하기 위한 다면체적 절단평면을 이용한 분지-절단해법(Branch-and-cut algorithm)과 열생성기법을 이용한 분지-평가해법(Branch-and-Price algorithm)을 제시하였다. 제시된 모형과 해법은 물류시스템의 설계 및 정보통신시스템의 통신설비 위치선정 등에 활용될 수 있다.