• 산업경영시스템학회지
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• 제35권1호
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• pp.10-15
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• 2012

This paper considers an economic design problem of a tree-based network which is a kind of computer network. This problem can be modeling to be an objective function to minimize installation costs, on the constraints of spanning tree and maximum traffic capacity of sub tree. This problem is known to be NP-hard. To efficiently solve the problem, a tabu list coupled genetic algorithm approach is proposed. Two illustrative examples are used to explain and test the proposed approach. Experimental results show evidence that the proposed approach performs more efficiently for finding a good solution or near optimal solution in comparison with a genetic algorithm approach.

• Selected Papers of The Society of Naval Architects of Korea
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• 제2권1호
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• pp.140-155
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• 1994

The hydrodynamic problem is treated here when a pressurized bag is submerged partially in the water and the end points of it oscillate. SES(Surface Effect Ship) has a bag filled with pressurized air at the stern in order to prevent the air leakage, and the pitch motion of SES is largely affected by the hydrodynamic force of the bag. The shape of a bag can be determined with the pressure difference between inside and outside. Once the hydrodynamic pressure is given, the shape of a bag can be obtained, however in order to calculate the hydrodynamic pressure we should know the shape change of the bag, and vice versa. Therefore the type of boundary condition on the surface of a bag is a moving boundary like a free surface boundary. The present paper describes the formulation of this problem and treats a linearized problem. The computations of the radiation problem for an oscillating bag are shown in comparison with the case that the bag is treated as a rigid body. The hydrodynamic forces are calculated for various values of the pressure inside the bag and the submerged depth.

• Transactions on Control, Automation and Systems Engineering
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• 제1권1호
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• pp.16-20
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• 1999

Like the usual systems, the industrial robot manipulator has some constraints for motion. Usually we hope that the manipulators move fast to accomplish the given task. The problem can be formulated as the time-optimal control problem under the constraints such as the limits of velocity, acceleration and jerk. But it is very difficult to obtain the exact solution of the time-optimal control problem. This paper solves this problem in two steps. In the first step, we find the minimum time trajectories by optimizing cubic polynomial joint trajectories under the physical constraints using the modified evolution strategy. In the second step, the controller is optimized for robot manipulator to track precisely the optimized trajectory found in the previous step. Experimental results for SCARA type manipulator show that the proposed method is very useful.

• International Journal of Advanced Culture Technology
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• 제4권3호
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• pp.48-55
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• 2016

Conventional techniques for solving the noise problem have problems to generate different results, depending on the image size and weight values of the used masks, and they require many operations by using a complex formula. In this paper, we propose an image enhancement algorithm to solve the noise problem in a simple, yet easy-to-use way. For this purpose, we determined the difference between the noise of the two adjacent pixels for the horizontal and vertical, and for the two diagonal directions that each of the noise problem occurred, and then we got the average value of these pixel values. Then, we solve the noise problem by using the optimal average value in accordance with occurrence of the noise in the horizontal and vertical, and two adjacent pixels in a diagonal direction. As a result, we got the result that the noise solution in a simple, yet easy-to-use method to obtain a resultant image.

• 대한가정학회지
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• 제46권1호
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• pp.15-24
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• 2008

Although the relationship between physical health problems and life satisfaction is well documented, less is known about the role of coping strategies, in particular strategies for coping via religious or spiritual means. To investigate the relationships among these factors, data collected with questionnaires completed by 326 adult alcoholics at a rehabilitation agency. Significant Physical Health Problem $\times$ Religious Coping buffer interactions were found in the relationship between physical health problem and life satisfaction. Moderated regression analysis showed that religious coping reduced the impact of physical health problem on life satisfaction. Implications for practice are discussed.

• 대한산업공학회지
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• 제28권1호
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• pp.99-104
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• 2002

This paper presents a method of sensitivity analysis for the infeasible interior point method when a new variable is introduced. For the sensitivity analysis in introducing a new variable, we present a method to find an optimal solution to the modified problem. If dual feasibility is satisfied, the optimal solution to the modified problem is the same as that of the original problem. If dual feasibility is not satisfied, we first check whether the optimal solution to the modified problem can be easily obtained by moving only dual solution to the original problem. If it is possible, the optimal solution to the modified problem is obtained by simple modification of the optimal solution to the original problem. Otherwise, a method to set an initial solution for the infeasible interior point method is presented to reduce the number of iterations required. The experimental results are presented to demonstrate that the proposed method works better.

• 기술혁신학회지
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• 제20권1호
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• pp.239-270
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• 2017

이 연구는 대표이사, 최대주주, 외국인의 지분율 변화가 R&D 지출 강도에 어떤 영향을 미치는지에 대해, 2007년부터 2014년까지 유가증권 및 코스닥 시장에 상장된 553개 제조업체를 대상으로 패널 분석을 실시하였다. 그 결과, (1) 대표이사 지분율과 R&D 지출간의 관계에 대해서, 코스닥 기업에서는 역-U자형 관계가 있음을 확인하였다. 이러한 비선형 관계는 이론 연구나 미국 기업에 대한 실증 연구들과 합치하며, 경영자 주식소유가 R&D 관련 대리인 비용을 줄이는데 일정 부분 기여함을 보여준다. 한편 최대주주가 아닌 대표이사가 의미 있는 수준의 주식을 보유하는 경우가 드문 유가증권시장 기업에서는 유의한 관계를 발견하지 못했다. (2) 최대주주 지분율과 R&D 지출간의 관계에 대해서는, 유가증권시장 기업에서 음(-)의 상관관계를 발견하였는데 이는 최대주주가 R&D 활동에 제대로 영향력을 행사하지 못하거나, 최대주주와 외부 주주간의 대리인 문제 때문으로 판단된다. 코스닥 기업에서는 최대주주가 R&D에 부정적 영향을 미치지 않는 것으로 나타났는데, 전문성을 가진 창업자가 경영 일선에서 활동하는 경우가 많아서 이러한 대리인 문제가 덜 일어나기 때문으로 보인다. (3) 외국인 지분율과 R&D 지출 강도 사이에는 두 시장 모두 유의미한 관계를 확인하지 못했다. 본 연구는 소유구조가 R&D 활동에 미치는 영향 면에서 유가증권시장과 코스닥 기업들 간에 뚜렷한 차이가 있음을 처음으로 보이고, 이를 이론적으로 설명하였다는 점에서 기존 연구와 차별성이 있다.

• 한국군사과학기술학회지
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• 제19권1호
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• pp.43-49
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• 2016

This paper addresses the problem of the software update or upgrade of embedded equipments on a missile assembly with booster. Because the embedded equipments are assembled delicately and closely one another with various communication and power cables, they should be very carefully disassembled to directly upgrade the software of a certain embedded equipment. This may cause not only the costs for disassembly and reassembly but also additional tests to verify the completeness of the reassembled missile as a missile assembly with booster. This paper presents an indirect data transfer technique based on MIL-STD-1553B through Guidance Control Unit to easily upgrade the software of other equipments without any additional costs caused by disassembly and reassembly. The presented technique was successfully applied to the software upgrade of various equipments on real missile assembly with booster.

• 한국통신학회논문지
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• 제40권9호
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• pp.1719-1721
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• 2015

주파수 자동지정 알고리즘은 빈번한 환경 변화에 따라 주파수 재지정이 요구되는 군용 통신에서 중요하게 고려되고 있다. 본 논문에서는 주파수 자동지정 문제를 그래프 이론 관점에서 해결한다. 그래프의 색칠 이론을 기반으로 한 알고리즘을 제시하여 기존의 탐욕 알고리즘 보다 사용되는 주파수 개수를 0.77배 감소시키는 성능 향상을 확인하였다. 또한, 주파수 범위와 재사용률 간의 맞교환을 통하여 원하는 성능을 얻을 수 있는 하이브리드 알고리즘을 제시하였다.

• 전자공학회논문지SC
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• 제48권5호
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• pp.52-58
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• 2011

유도탄의 유도제어시스템은 오토파일롯, 유도법칙 및 호밍필터 등의 다양한 제어시스템으로 구성된다. 기존에는 이러한 유도제어시스템을 설계하기 위해 이러한 각 단계의 제어기를 개별적으로 최적화하는 방식이 널리 활용되었다. 하지만 이러한 방식의 경우 각 단계의 최적화시 시간과 비용이 많이 필요함은 물론, 전체시스템의 관점에서의 최적화라 볼 수 없다. 본 논문에서는 최적화 툴을 이용한 유도제어시스템 설계를 위해 각 제어시스템 설계 시 필요한 성능지수 및 구속조건을 정식화하고, 이를 통합적으로 최적화하는 기법을 제안한다.