• 대한산업공학회지
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• 제26권2호
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• pp.155-164
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• 2000

Recently Fiber-optic Micro-cellular Wireless Network is considered to solve frequent handoffs and local traffic unbalance in microcellular systems. In this system, central station which is connected to several microcells by optical fiber manages the channels. We propose an efficient sectorization algorithm which dynamically clusters the microcells to minimize the blocked and handoff calls and to balance the traffic loads in each cell. The problem is formulated as an integer linear programming. The objective is to minimize the blocked and handoff calls. To solve this real time sectorization problem the Tabu Search is considered. In the tabu search intensification by Swap and Delete-then-Add (DTA) moves is implemented by short-term memory embodied by two tabu lists. Diversification is considered to investigate proper microcells to change their sectors. Computational results show that the proposed algorithm is highly effective. The solution is almost near the optimal solution and the computation time of the search is considerably reduced compared to the optimal procedure.

• 한국컴퓨터정보학회논문지
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• 제21권6호
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• pp.77-81
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• 2016

This paper deals with the optimization problem that decides the routing of connection between multi-source and multi-sink. For this problem, there is only in used the mathematical approach as linear programming (LP) software package and has been unknown the polynomial time algorithm. In this paper we suggest the heuristic algorithm with $O(mn)^2$ time complexity to solve the optimal solution for this problem. This paper suggests the simple method that assigns the possible call flow quantity to augmenting path of ($s_i,t_i$) city pair satisfied with demand of ($s_i,t_i$). The proposed algorithm can be get the same optimal solution as LP for experimental data.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1193-1196
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• 1996

Genetic algorithm(GA) is useful to find optimal solution without any special mathematical modeling. This study presents to search optimal path of Autonomous Mobile Robot(AMR) by using GA without encoding and decoding procedure. Therefore, this paper shows that the proposed algorithm using GA can reduce the computation time to search the optimal path.

• 경영과학
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• 제33권1호
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• pp.77-87
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• 2016

I study optimal consumption and investment choices of an infinitely-lived economic agent with a general time-separable von Neumann-Morgenstern utility under general borrowing constraints against future labor income. An explicit solution is provided by the dynamic programming method. It is shown that the optimal consumption and risky investment decrease as the borrowing constraints become stronger.

• Reproductive and Developmental Biology
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• 제35권3호
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• pp.329-334
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• 2011

This study was conducted to establish a freezing method of miniature pig spermatozoa. The semen 더aculated from PWG M-type miniature pig was collected by gloved-hand method. The semen was diluted with same volume extender (m-Modena B). The frozen solution used frozen solution of four different (LEY, TCG, BF-5 and m-Modena+egg yolk) for find optimal frozen solution in miniature pig sperm. The diluted semen for frozen rate assay was added to LEY solution (solution I: 11% lactose+egg yolk; solution II: solution I+glycerol+OEP), and frozen depending on freezing rate by the three different freezing methods (A: until $5^{\circ}C$ for 1 hrs, holding at $-102^{\circ}C$ for 10 min; B: until $5^{\circ}C$ for 2 hrs, holding at $-102^{\circ}C$ for 10 min; C: until $5^{\circ}C$ for 3 hrs, holding at -80 and $-102^{\circ}C$ for 10 min). Semen cooled until $5^{\circ}C$ was added with glycerol 1, 3 and 5%, and take a equilibrium time for 0, 10 and 30min. Frozen-thawed sperm were evaluated for viability, acrosomal status and morphological abnormality. The results of frozen-thawed sperm ability by frozen solution, viability was higher in LEY solution compared to other three different frozen solution. AR pattern of LEY solution were lower than other three different frozen solution. The results of freezing rate, viability was higher in B method compared to other methods (p<0.05). Acrosomal statute was intacted in A and B methods than C method. The experiment for glycerol condition was showed that sperm viability was higher in extender with 1% and 3% glycerol and equilibrium time of 0 min. The acrosome damage was lower in extender with 1% glycerol and equilibrium time of 10 min than other conditions. In conclusion, the optimal conditions for cryopreservation of miniature pig spermatozoa obtained in LEY frozen solution, cooling rate of 1~2 hrs, 1~3% glycerol concentrations and glycerol equilibrium time of 0~10 min.

• 제어로봇시스템학회논문지
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• 제20권1호
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• pp.1-5
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• 2014

In this paper, we propose an optimal fixed-lag FIR (Finite-Impulse-Response) smoother for a class of discrete time-varying state-space signal models. The proposed fixed-lag FIR smoother is linear with respect to inputs and outputs on the recent finite horizon and estimates the delayed state so that the variance of the estimation error is minimized with the unbiased constraint. Since the proposed smoother is derived with system inputs, it can be adapted to feedback control system. Additionally, the proposed smoother can give more general solution than the optimal FIR filter, because it reduced to the optimal FIR filter by setting the fixed-lag size as zero. A numerical example is presented to illustrate the performance of the proposed smoother by comparing with an optimal FIR filter and a conventional fixed-lag Kalman smoother.

• 한국수정란이식학회지
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• 제9권2호
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• pp.173-180
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• 1994

The present experirnents on cryopreservation were carried out to investigate effect of solution toxicity, equilibration time and cell stages on the post-thaw survival of mouse morulae and blastocyst embryos cryopreserved by vitrification in EFS solution. The mouse embryos were exposed to the EFS solution in one step at room temperature, kept in the EFS solution during different period for toxicity test, vitrified in liquid nitrogen and thawed rapidly. After the mouse morulae embryos were exposed to EFS solution for 2 and 5 ruin. at room temperature and then they were washed in 0.5 M sucrose solution and basal mediurn(D-PBS + 10% FCS), they were cultured to examined cryoprotectant toxicity induced injury during exposure, most of embryos developed to expanded blastocysts(100 and 90.0%). However, when the exposure time was extended to 10 and 20 min, these development rates dropped dramatically in 10 ruin. (75.0%) and 20 ruin. (4.5%), respectively. When the compacted morulae were vitrified in EFS solution after equilibration for 2 and 5 min, the embryos have developed to normal blastocyst following thawing, washing and culture processes was 89.3 and 89.6%. However, when the exposure time was expanded to 10 ruin, this survival rate dropped to 68.8%. When the blastocyst were vitrified in EFS solution after equilibration for 2, 5 and 10 minutes, the survival rate of embryos which developed to normal blastocyst following thawing and culture processing were 58.5, 46.7 and 22.4%, respectively. The optimal time of equilibration of mouse morula and blastocysts in EFS solution seemed o be 2 and 5 ruin.

• 정보처리학회논문지B
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• 제17B권5호
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• pp.389-398
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• 2010

차량 경로 스케줄링 문제(VRSPTW, the Vehicle Routing and Scheduling Problem with Time Window)는 여러 고객의 시간 제약과 요구량을 만족시키면서 최소 이동 비용을 가지는 경로를 구성하는 문제이다. 이 문제는 NP-Hard 문제이기 때문에 해를 산출하는데 시간이 오래 걸린다. 본 연구는 VRSPTW를 빠른 시간 내에 최근사해를 구하기 위한 멀티 비용 함수(Multi Cost Function)를 갖는 개미 군집 최적화(Ant Colony Optimization)을 이용한 휴리스틱을 제안하였다. 멀티 비용 함수는 각 개미가 다음 고객 노드로 이동하기 위해 비용을 평가할 때 거리, 요구량, 각도, 시간제약에 대해 서로 다른 가중치를 반영하여 우수한 초기 경로를 구할 수 있도록 한다. 본 연구의 실험결과에서 제안된 휴리스틱이 Solomon I1 휴리스틱과 기회시간이 반영된 하이브리드 휴리스틱보다 효율적으로 최근사 해를 얻을 수 있음을 보였다.

• 산업공학
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• 제18권4호
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• pp.370-381
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• 2005

This study is concerned with seeking the optimal allocation(disposition) for maximizing utility of consolidating old fashioned and new air defense weapon system like SAM-X(Patriot missile) and developing efficient solution algorithm based on simulated annealing(SA) algorithm. The SED(selection by effectiveness degree) procedure is implemented with an enhanced SA algorithm in which neighboring solutions could be generated only within the optimal feasible region by using a specially designed PERTURB function. Computational results conducted on the problem sets with a variety of size and parameters shows the significant efficiency of our SED algorithm over existing methods in terms of both the computation time and the solution quality.

• 한국경영과학회지
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• 제29권3호
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• pp.145-155
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• 2004

The design of a communication network has long been a challenging optimization problem. Since the optimal design of a network topology is a well known as a NP-complete problem, many researches have been conducted to obtain near optimal solutions in polynomial time instead of exact optimal solutions. All of these researches suggested diverse heuristic algorithms that can be applied to network design problems. Among these algorithms, a simulated annealing algorithm has been proved to guarantee a good solution for many NP-complete problems. in applying the simulated annealing algorithms to network design problems, generating mechanisms for initial solutions and candidate solutions play an important role in terms of goodness of a solution and efficiency. This study aims at analyzing these mechanisms through experiments, and then suggesting reliable mechanisms.