• 대한수학회보
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• 제26권2호
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• pp.127-134
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• 1989

This paper proposes a deformation method for solving practical nonlinear programming problems. Utilizing the nonlinear parametric programming technique with Quasi-Newton method [6,7], the method solves the problem by imbedding it into a suitable one-parameter family of problems. The approach discussed in this paper was originally developed with the aim of solving a system of structural optimization problems with frequently appears in various kind of engineering design. It is assumed that we have to solve more than one structural problem of the same type. It an optimal solution of one of these problems is available, then the optimal solutions of thel other problems can be easily obtained by using this known problem and its optimal solution as the initial problem of our parametric method. The method of nonlinear programming does not generally converge to the optimal solution from an arbitrary starting point if the initial estimate is not sufficiently close to the solution. On the other hand, the deformation method described in this paper is advantageous in that it is likely to obtain the optimal solution every if the initial point is not necessarily in a small neighborhood of the solution. the Jacobian matrix of the iteration formula has the special structural features [2, 3]. Sectioon 2 describes nonlinear parametric programming problem imbeded into a one-parameter family of problems. In Section 3 the iteration formulas for one-parameter are developed. Section 4 discusses parametric approach for Quasi-Newton method and gives algorithm for finding the optimal solution.

• 한국지능시스템학회논문지
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• 제18권2호
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• pp.212-215
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• 2008

본 논문에서 개선된 Dijkstra 알고리즘과 입자 군집 최적화를 이용한 최적 경로 계획 알고리즘을 제안한다. 최적의 경로를 구하기 위해 우선 이동 로봇 공간에서 MAKLINK를 작성하고 MAKLINK와 관련한 그래프를 얻는다. 여기서 MAKLINK는 장애물의 꼭지점을 연결하면서 볼록집합이 만들어지도록 하는 모서리의 집합을 의미한다. 얻은 그래프에서 출발점과 도착점을 포함하여 Dijkstra 알고리즘을 이용하여 최소 비용 최적 경로를 얻고 이 최적의 경로에서 개선된 Dijkstra경로를 얻는다. 마지막으로 개선된 Dijkstra경로에서 입자 군집 최적화를 적용하여 최적의 경로를 얻는다. 제안된 방법이 논문[1]에 나온 결과보다 더 좋은 성능을 갖는다는 것을 실험을 통해 입증한다.

• 한국콘텐츠학회논문지
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• 제18권2호
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• pp.169-177
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• 2018

가뭄, 홍수 등의 자연재난으로 인해 인명 손실이 많이 발생되고 있다. 특히 도시지역에 발생되는 집중호우로 인한 침수 피해는 인명 및 구조물에 심각한 피해를 발생시킨다. 이에 따라 본 연구에서는 침수피해가 높은 도시지역을 대상으로 사람들이 안전하게 대피할 수 있도록 하는 최적 대피경로에 관한 연구를 수행하였다. 이를 위해 Flo-2D 모형 및 A*알고리즘에 대하여 고찰하여 최적 대피경로를 도출하고자 하는 방법론을 설정하였다. Flo-2D모형을 통해 위험지역을 도출하였으며, 인원수가 많은 시작지점을 선정하고 홍수재난에 대해 안전한 대피지점을 선정할 수 있도록 하는 방법을 제시하였다. 그리고 A* 알고리즘을 활용하여 출발지점에서 안전한 대피지점까지 위험지점을 거치지 않고 최적의 대피경로를 도출하였다. 본 연구를 통해 대피경로 제시뿐만 아니라 도로정비와 대피시설물에 대한 사전 대비 자료로 활용될 수 있을 것으로 판단된다.

• 로봇학회논문지
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• 제18권1호
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• pp.1-9
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• 2023

This paper presents an optimal path planning strategy for aerial searching and surveying of a user-designated area using multiple Unmanned Aerial Vehicles (UAVs). The method is designed to deal with a single unseparated polygonal area, regardless of polygonal convexity. By defining the search area into a set of grids, the algorithm enables UAVs to completely search without leaving unsearched space. The presented strategy consists of two main algorithmic steps: cellular decomposition and path planning stages. The cellular decomposition method divides the area to designate a conflict-free subsearch-space to an individual UAV, while accounting the assigned flight velocity, take-off and landing positions. Then, the path planning strategy forms paths based on every point located in end of each grid row. The first waypoint is chosen as the closest point from the vehicle-starting position, and it recursively updates the nearest endpoint set to generate the shortest path. The path planning policy produces four path candidates by alternating the starting point (left or right edge), and the travel direction (vertical or horizontal). The optimal-selection policy is enforced to maximize the search efficiency, which is time dependent; the policy imposes the total path-length and turning number criteria per candidate. The results demonstrate that the proposed cellular decomposition method improves the search-time efficiency. In addition, the candidate selection enhances the algorithmic efficacy toward further mission time-duration reduction. The method shows robustness against both convex and non-convex shaped search area.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.79-80
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• 2007

This paper deals with generating multi-ped mobile robot's optimal path and its simulation. The multi-ped robot has six-legs which make it possible to move actively by attached driving wheel at the end of legs. The simulation environment is created similarly to the indoor environment as simple obstacles and walls. Also simulator can reconstruct an simulation environment. In this paper, the suggested simulator can generate the optimal path from starting point to destination by applying the A* algorithm and Bug2 algorithm. Then it is possible to check algorithms as 3D screen and we can simulate under the generated path.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.727-732
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• 2002

This study is to develop the model of alignment optimization based on design criteria by approaching through alignment of railway design and problems in economy, environment and technology for satisfying traffic volume of the main roads caused by economical and social developments. Now, Geographic Information System isn't applied when designing a present railway in home. And the design of railway alignment is still set on importance of transition curves and cant according to passenger comfort in abroad so tile study of railway alignment is at initiation phase so far. This paper is about decision of optimal alignment between two stations such as starting point and ending point automatically using GIS in optimization of railway alignment. A route between Sungsan city and Shinpung city is the training area and the study compared and evaluated optimal railway route by GIS automatically with present railway route designed. Present optimal fomulas was used in this study for optimization of railway alignment. The model of optimization of railway alignment was developed through topographical elements and it was mentioned by the model of road alignment because of the similarity in design of alignment. But the design of lateral track irregularities, cant fur passenger comfort and motion sickness fellowed by train rolling have to be considered more. Anyway, this study farmed the basis of using GIS and the study should be keep going on in the future.

• 전기학회논문지
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• 제56권4호
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• pp.699-704
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• 2007

In this paper, optimized model was designed for the starting characteristic of the Single-Phase Line-Start Permanent Magnet Synchronous Motor by using the Design of Experiment. A field pole angle, thickness and distance from center axis of permanent magnet were selected as design factor. We executed the transient state characteristic analysis of 8 test models. The transient state characteristic analysis was executed by using the 2 dimensional Finite Element Method and the Time Difference Method. We checked the fact that the selected design factor affected starting characteristic of the Line-Start Permanent Magnet Synchronous Motor. Depend on this result we found the optimized design point by using the response optimization.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.188-191
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• 2002

To reduce the bit-rate of video sequences by removing temporal redundancy, motion estimation techniques have been developed. However, the high computational complexity of the problem makes such techniques very difficult to be applied to high-resolution applications in a real time environment. For this reason, low computational complexity motion estimation algorithms are viable solutions. If a priori knowledge about the motion of the current block is available before the motion estimation, a better starting point for the search of n optimal motion vector on be selected and also the computational complexity will be reduced. In this paper, we present an adaptive block matching algorithm based on temporal correlations of consecutive image frames that defines the search pattern and the location of initial starting point adaptively to reduce computational complexity. Experiments show that, comparing with DS(Diamond Search) algorithm, the proposed algorithm is about 0.1∼0.5(㏈) better than DS in terms of PSNR and improves as much as 50% in terms of the average number of search points per motion estimation.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1294-1301
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• 2008

Under passive RFID environment, this paper presents a new localization of a mobile robot traversing over the floor covered with tags, which is superior to existing methods in terms of estimation performance and cost effectiveness. Basically, it is assumed that a mobile robot is traveling along a series of straight line segments, each segment at a certain constant velocity, and that the number of tags sensed by a mobile robot at each sampling instant is at most one. First, for a given line segment with known starting point, the velocity and position of a mobile robot is estimated using the spatial and temporal information acquired from the traversed tag. Some discussions are made on the validity of the basic assumptions and the localization for the initial segment with unknown starting point. Second, for a given tag distribution density, the optimal tag arrangement is considered to reduce the position estimation error as well as to make easy the tag attachment on the floor. After reviewing typical tag arrangements, the pseudorandom tag arrangement is devised inspired from the Sudoku puzzle, a number placement puzzle. Third, through experiments using our passive RFID localization system, the validity and performance of the mobile robot localization proposed in this paper is demonstrated.

• Journal of Biosystems Engineering
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• 제29권6호
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• pp.515-520
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• 2004

A device far estimating the optimal artificial insemination time consisted of a computer, RS module, and six direct-reflex photo-sensors. Program was written in LabWindows CVI. In order to establish references for estimating optimal artificial insemination time, lying rate of the thirty three $Berkshire{\times}Hampshire crossbred sows (parity 5 to 6) was recorded from 2 days after moving into stalls to artificial insemination using a time lapse VCR and was measured every hour with one minute interval using the scan point sampling method. Twenty low hours in a day were divided into three comparing periods : 21:00 to 06:59, 07:00 to 13:59, and 14:00 to 20:59. If sum of the percentages of tying during a comparing period was less than the reference value, the starting hour of the comparing period was considered as onset of estrus and the optimal artificial insemination time was estimated at 20 to 24 hours after onset of estrus. The experimental device was evaluated with twenty five $Berkshire{\times}Hampshire$ crossbred sows (parity 2 to 7) and 23 of 25 sows $(92\%)$ were pregnant. This result suggests that the experimental device is excellent in performance for estimating optimal artificial insemination time.