• 천문학회보
• /
• 제38권1호
• /
• pp.64.2-64.2
• /
• 2013

Korea Astnonomy and Space Science Institute (KASI) operates two solar radio observing facilities, the Korean station of the e-CALLISTO and the Korean Solar Radio Burst Locator (KSRBL). The e-CALLISTO station had suffered from tracking problem for past several years. Since 2011, KASI has developed a new tracking system, and recently the antenna has regained the its sun-tracking capability and full day-time coverage. The KSRBL also suffered from the control computer breakdown last year. After one year of operational gap, the KSRBL restored its normal daily observation. We also expanded the data server storage capacity, to store the full original data of 25 ms integration time and 0.25 MHz frequency resolution, amounting to about 80 GB per day.

• 제어로봇시스템학회논문지
• /
• 제12권11호
• /
• pp.1102-1110
• /
• 2006

This paper addresses the problem of computing grasp stability of the object for two-fingered robots in two dimensions. The concepts of force-closure and dual space are introduced and discussed in novel point of view, and we transform friction cones in a robot work space to line segments in a dual space. We newly define a grasp stability index by calculating intersection condition between line segments in dual space. Moreover, we propose a method to find the optimal grasp points of the given object by comparing the defined grasp stability index. Its validity and effectiveness are investigated and verified by simulations for quadrangle object and elliptic objects.

• Journal of Astronomy and Space Sciences
• /
• 제21권4호
• /
• pp.399-416
• /
• 2004

국내 최초의 과학위성인 과학기술위성 1호(STSAT-1)의 주 탑재체 원자외선분광기(FIMS; Far-utraviolet IMaging Spectrograph)는 2003년 9월 발사된 이후로, 다양한 관측을 수행하고 있으나 위성체에서 제공하는 자세정보의 시각오차의 문제점이 발견되어 시각오차를 보정하기 위한 연구가 수행되었다. 시각오차의 보정 후에 잘 알려진 천체의 관측결과를 이용하여 FIMS와 위성체 좌표계 사이의 기계적인 정렬오차에 의해 발행하는 FIMS의 시선방향과 위성체에서 제공하는 자세의 차이를 단파장대와 장파장대에 대하여 각각 계산하였다. 또한, 자세정보의 월별 상태 및 정밀도를 조사하였다. FIMS의 관측방법의 특성상 FIMS로부터 얻어진 영상은 위치별로 서로 다른 노출시간을 갖는다. 이러한 노출시간을 보정하는 방법을 기술하였다. 이 연구의 결과는 FIMS 자료분석을 위해 반드시 필요한 내용이며 추후 좀 더 정밀한 자세정보 보정을 위한 참고 자료로 활용될 것이다.

• 한국전산구조공학회논문집
• /
• 제34권4호
• /
• pp.221-230
• /
• 2021

전역 최적화 문제의 해를 유전 알고리즘을 사용하여 얻어 완전파형역산을 수행하고 층상 반무한체의 물성치를 추정하는 기법을 제안한다. 조화 수직 하중이 작용하는 층상 반무한체의 동적 응답을 측정하고, 이를 추정 물성치를 사용하여 계산된 응답과 비교한다. 응답의 추정치는 mid-point integrated finite element와 perfectly matched discrete layer를 사용하여 구성된 thin-layer model로부터 얻는다. 전역 최적화 문제의 목적 함수는 응답의 관측치와 추정치의 차이에 대한 L2-norm으로 계산된다. 유전 알고리즘을 사용하여 전역 최적화 문제의 해를 구하여 완전파형역산을 수행한다. 제안된 기법을 기본 진동 모드 뿐만이 아니라 고차 진동 모드도 우세한 다양한 층상 반무한 매질에 적용하여, 측정치가 잡음을 포함하지 않는 경우와 포함하는 경우 모두에 대해서 제안된 완전파형역산 기법은 층상 반무한체의 재료 특성을 추정하는데 적합함을 확인할 수 있다.

• 한국농촌건축학회논문집
• /
• 제17권4호
• /
• pp.67-74
• /
• 2015

Due to an inability to accommodate for the rapidly increasing number of printed materials, Korean academic libraries are facing serious space shortage problems. Very few academic institutions have the funds to expand existing libraries or construct new facilities in order to accommodate the influx of printed materials. Despite not having the luxury to create new space, many establishments continue to implement the open access system. Seeing that such a system is only user friendly when used in a spacious facility, the maintenance of the open access system is unreasonable. Only few libraries consider the space efficient closed access system which helps to resolve storage space shortage. In the current state of the problem, improving the efficiency to which books are stored in existing storage areas within a library facility is the only appropriate solution. Enacting methods to improve physical space utilization within a fixed volume library facility will undoubtedly diminish the space shortage issue at hand. In this article, several space efficiency improvement approaches are discussed. Methods of book storage plan re-layout (floor, plan, ceiling, height, bookshelf design), book arrangement possibilities, and the reduction of the physical volume of reserved materials are each examined.

• Management Science and Financial Engineering
• /
• 제20권1호
• /
• pp.17-19
• /
• 2014

In this paper, we consider an interesting variant of the inverse minimum traveling salesman problem. Given an instance (G, w) of the minimum traveling salesman problem defined on a metric space, we fix a specified Hamiltonian cycle $HC_0$. The task is then to adjust the edge cost vector w to w' so that the new cost vector w' satisfies the triangle inequality condition and $HC_0$ can be returned by the minimum spanning tree algorithm in the TSP-instance defined with w'. The objective is to minimize the total deviation between the original and the new cost vectors with respect to the $L_1$-norm. We call this problem the inverse metric traveling salesman problem against the minimum spanning tree algorithm and show that it is closely related to the inverse metric spanning tree problem.

• 대한산업공학회지
• /
• 제23권4호
• /
• pp.709-717
• /
• 1997

For an undirected graph G=(V, E), the Rural Postman Problem (RPP) is a problem that finds a minimum cost tour that must pass edges in E'($\subseteq$ E) at least once. RPP, such as Traveling Salesman Problem (TSP), is known as an NP. Complete problem. In the previous study of RPP, he structure of the chromosome is constructed by E' and the direction of the edge. Hence, the larger the size of IE' I is, the larger the size of the chromosome and the size of the solution space are. In this paper, we transform the RPP into a Hamiltonian graph and use a genetic algorithm to solve the transformed problem using restructured chromosomes. In the simulations, we analyze our method and the previous study. From the simulation results, it is found that the results of the proposed method is better than those of the previous method and the proposed method also obtains the near optimal solution in earlier generations than the previous study.

• 한국경영과학회지
• /
• 제22권2호
• /
• pp.125-137
• /
• 1997

We are concerned with the packing policy determines the optimal packing of products with variable sizes to minimize the penalty costs for idle space and product spliting. Optimal packing problem is closely related to the optimal packet/record sizing problem in that randomly generated data stream with variable bytes are divided into a unit of packet/record for transmitting or storing. Assuming the product size and the production period are independently determined by renewal process, we can approximate the renewal process and formulate the optimization problem that minimize the expected packing cost for a production period. The problem is divided into two cases according to whether a product is allowed to split or not. Computational results for various distributions will be given to verify the approximation procedure and the resulting optimization problem.

• 한국CDE학회논문집
• /
• 제4권3호
• /
• pp.259-268
• /
• 1999

In order to reduce the cost of product and save the processing time, optimal nesting of two-dimensional part is an important application in number of industries like shipbuilding and garment making. There have been many studies on finding the optimal solution of two-dimensional nesting. The problem of two-dimensional nesting has a non-deterministic characteristic and there have been various attempts to solve the problem by reducing the size of problem rather than solving the problem as a whole. Heuristic method and linearlization are often used to find an optimal solution of the problem. In this paper, theoretical and practical nesting algorithm for rectangular, circular and irregular shape of two-dimensional parts is proposed. Both No-Fit-Polygon and Minkowski-Sum are used for solving the overlapping problem of two parts and the dynamic programming technique is used for reducing the number search spae in order to find an optimal solution. Also, nesting designer's expertise is complied into the proposed algorithm to supplement the heuristic method.

• 한국CDE학회논문집
• /
• 제9권3호
• /
• pp.226-237
• /
• 2004

If the topology changes in the re-generation step of the history-based and feature-based CAD systems, it is difficult to identify an entity in the old model and find the same entity in the new model. This problem is known as 'persistent naming problem'. To exchange parametric CAD models, the persistent naming problem and the naming mapping problem must be solved among different CAD system, which use different naming scheme. For CAD model exchange the persistent naming has its own characteristics compare to that for CAD system development. This paper analyses previous researches and proposes a solution to the persistent naming problem for CAD model exchanges and to the naming mapping problem among different naming schemes.