• International Journal of Naval Architecture and Ocean Engineering
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• 제7권1호
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• pp.87-99
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• 2015

In recent years, the development of autonomous surface vehicles has been a field of increasing research interest. There are two major areas in this field: control theory and path planning. This study focuses on path planning, and two objectives are discussed: path planning for Unmanned Surface Vehicles (USVs) and implementation of path planning in a real map. In this paper, satellite thermal images are converted into binary images which are used as the maps for the Finite Angle $A^*$ algorithm ($FAA^*$), an advanced $A^*$ algorithm that is used to determine safer and suboptimal paths for USVs. To plan a collision-free path, the algorithm proposed in this article considers the dimensions of surface vehicles. Furthermore, the turning ability of a surface vehicle is also considered, and a constraint condition is introduced to improve the quality of the path planning algorithm, which makes the traveled path smoother. This study also shows a path planning experiment performed on a real satellite thermal image, and the path planning results can be used by an USV.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.514-521
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• 2004

A routing is the path that an actual train set follows as it moves from one train to another train in a timetable. The number of routings is equivalent to the number of trainsets required to cover the timetable. The primary factors of rolling stock requirement plan include evaluating the minimum number of routings. This can be formulated as a set partitioning problem and solved using enumeration method or column generation method. In this paper we presents an enumeration algorithm which is useful to implement the enumeration method for the rolling stock requirement plan.

• 한국노년학
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• 제31권4호
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• pp.871-884
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• 2011

표준장기요양이용계획서는 노인장기요양보험 이용자와 가족의 급여이용을 지원하기 위한 목적으로 도입된 일종의 케어플랜이라고 할 수 있다. 본 연구는 가족수발자가 인지하는 표준장기요양이용계획서의 질과 만족도, 활용도를 파악하고 이들 간의 관계를 파악하는 것을 목적으로 한다. 연구자료는 2008년 11월~12월 현재 노인장기요양보험 1~3등급 판정을 받고 재가장기요양서비스를 이용하고 있는 수급자의 가족수발자를 대상으로 가정방문면접조사를 통해 수집하였고, 총 944명의 가족수발자 가운데 표준장기요양이용계획서를 읽어본 경험이 있으며 설문을 완성한 351명이 최종분석대상이 되었다. 조사도구는 가족수발자와 수급자의 인구사회학적 특성 및 장기요양특성, 질 측정항목(9개), 전반적 만족도 측정항목(1개), 활용도 측정항목(2개) 등을 포함하였고, 질, 만족도 및 활용도 간의 관계를 파악하기 위해 경로분석을 실시하였다. 연구결과, 표준장기요양이용계획서의 질은 장기요양 욕구평가 영역, 장기요양 이용계획 영역, 월 한도액 관리지원 영역 등 세 개 영역으로 구분되었고, 모든 영역이 만족도 및 활용도와 유의한 상관관계를 나타냈다. 다음으로 경로분석 결과, 표준장기요양이용계획서의 장기요양 욕구평가 영역의 질(간접효과, 경로계수=0.077)과 전반적 만족도(전체효과, 경로계수=0.324)가 활용도에 통계적으로 유의한 영향을 미쳤다. 본 연구결과는 표준장기요양이용계획서의 역할을 향상시키기 위한 전략을 개발하는데 도움이 될 것으로 기대된다.

• Journal of Biosystems Engineering
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• 제24권4호
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• pp.301-308
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• 1999

Path planning for field operation of agricultural machinery is an indispensible part for precision farming or autonomous field operation. In this study, two algorithms (I, II) of generating a time-based shortest operation path were suggested to plan an optimal operation of an agricultural tractor-implement in a rectangular shaped field. The algorithms were based on modification of a minimum spanning tree algorithm, and applied for tractor-implement operations. the generated path was consisted of round operation and returning operation sections. The number of round operation was determined from the condition that a tractor can turn smoothly at headlands. The performance of the algorithms was evaluated by the calculation number for path generation and the total path length generated. Their stability was affected by the number of returning operation, but the algorithm II was considered to be more stable. In addition, the performances of the developed algorithms were compared with those of the conventional field operations at selected field sizes and shapes. The results showed that the algorithms could reduce field operation time greatly. For a 100m$\times$40m field, the reduced path length was 78m. The study also included an user interface program for implementing the algorithms and generating GPS coordinates that could be used in GIS softwares for precision farming.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.327-334
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• 2011

It is necessary that UGV(Unmanned Ground Vehicle) should generate a real-time travesability index map by analyzing raw terrain information to travel autonomously tough terrain which has various slope and roughness values. In this paper, we propose a local path planning method, $MA^*$(Modified $A^*$) algorithm, using DVGM (Directional Velocity Grid Map) for unmanned ground vehicle. We also present a path optimization algorithm and a path smoothing algorithm which regenerate a pre-planned local path by $MA^*$ algorithm into the reasonable local path considering the mobility of UGV. Field test is conducted with UGV in order to verify the performance of local path planning method using DVGM. The local path planned by $MA^*$ is compared with the result of $A^*$ to verify the safety and optimality of proposed algorithm.

• 전기학회논문지
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• 제64권10호
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• pp.1479-1485
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• 2015

Robot's technology was very simple and repetitive in the past. Nowadays, robots are required to perform intelligent operation. So, path planning has been studied extensively to create a path from start position to the goal position. In this paper, potential field algorithm was used for path planning in dynamic environments. It is used for a path plan of mobile robot because it is elegant mathematical analysis and simplicity. However, there are some problems. The problems are collision risk, avoidance path, time attrition. In order to resolve path problems, we amalgamated potential field algorithm with the artificial neural network system. The input of the neural network system is set using relative velocity and location between the robot and the obstacle. The output of the neural network system is used for the weighting factor of the repulsive potential function. The potential field algorithm problem of mobile robot's path planning can be improved by using artificial neural network system. The suggested algorithm was verified by simulations in various dynamic environments.

• 환경영향평가
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• 제31권4호
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• pp.201-213
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• 2022

도시의 환경문제 해결과 관리방안으로 자연기반해법(Nature based Solution, NbS)이 대두되면서 도시지역의 녹지 확보 및 관리가 강조되고 있다. 개발 압력이 높은 도시지역은 녹지의 파편화 및 단절로 도시녹지의 연속성 확보를 위한 계획적 접근이 필요하다. 그러나 현행 제도에서 녹지축은 구체적인 녹지와 연결이 필요한 경로의 위치를 제공하지 못하고, 개별 녹지조성사업과 연계되지 못해 연속성 관점에서 일관된 녹지관리 체계로 활용성이 낮다. 따라서 본 연구는 NDMI (Normalized Difference Moisture Index), 불투수율, 녹지조성비용의 정보를 기반으로 연결경로를 도출할 수 있는 방안을 구상하고 수원시에 시범 적용하여 확인하였다. 본 연구에서 제안하는 방법을 통해 기존의 녹지축보다 비용효율성이 높은 구체적인 연결경로의 도출 가능성을 확인하였으며, 계획적 활용 방안에 대해서 논의하였다.

• 제어로봇시스템학회논문지
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• 제17권7호
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• pp.651-658
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• 2011

An efficient modified $D^*$ lite algorithm is suggested, which can perform online path planning for mobile robots in dynamic indoor environment. Online path planning should plan and execute alternately in a short time, and hence it enables the robot avoid unknown dynamic obstacles which suddenly appear on robot's path. Based on $D^*$ Lite algorithm, we improved representation of edge cost, heuristic function, and priority queue management, to build a modified $D^*$ Lite algorithm. Performance of the proposed algorithm is revealed via extensive simulation study.

• 한국정밀공학회지
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• 제26권7호
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• pp.73-80
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• 2009

This paper describes a path planning algorithm, which is the minimal turning path based on the shape and size of the cell to clean up the whole area with two cleaning robots. Our method divides the whole cleaning area with each cell by cellular decomposition, and then provides some path plans among of the robots to reduce the rate of energy consumption and cleaning time of it. In addition we suggest how to plan between the robots especially when they are cleaning in the same cell. Finally simulation results demonstrate the effectiveness of the algorithm in an unknown area with multiple robots. And then we compare the performance index of two algorithms such as total of turn, total of time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.252-254
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• 2005

Completer coverage path planning requires the robot path to cover every part of the workspace, which is an essential issue in cleaning robots and many other robotic applications such as vacuum robots and painter robots. In this paper, a novel Water Flowing Algorithm (WFA) is proposed for cleaning robots to complete coverage path planning in unknown environment without obstacles. The robot covers the whole workspace just like that water fills up a container. First the robot goes to the lowest point in the workspace just like water flows to the bottom of the container. At last the robot will come to highest point in the workspace just like water overflows from the container and simultaneously the robot has covered the whole workspace. The computer simulation results show that the proposed algorithm enable the robot to plan complete coverage paths.