• Title/Summary/Keyword: 보로노이

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The Cooperate Navigation for Swarm Robot Using Centroidal Voronoi Tessellation (무게중심 보로노이 테셀레이션을 이용한 군집로봇의 협조탐색)

  • Bang, Mun-Seop;Joo, Young-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.1
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    • pp.130-134
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    • 2012
  • In this paper, we propose a space partitioning technique for swarm robots by using the Centroidal Voronoi Tessellation. The proposed method consists of two parts such as space partition and collision avoidance. The space partition for searching a given space is carried out by a density function which is generated by some accidents. The collision avoidance is implemented by the potential field method. Finally, the numerical experiments show the effectiveness and feasibility of the proposed method.

An Implementation of Method to Determine Search Space of Hierarchical Path Algorithm for Finding Optimal Path (최적 경로 탐색을 위한 계층 경로 알고리즘의 탐색 영역 결정 기법의 구현)

  • Lee, Hyoun-Sup;Yun, Sang-Du;Kim, Jin-Deog
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.05a
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    • pp.835-838
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    • 2008
  • Many researches on hierarchical path search have been studied so far. Even though partitioning regions is essential part, the researches are not enough. This paper proposes two efficient methods to partition regions: 1)a method based on voronoi algorithm in which a major node is central point of a region, 2) a method based on fired grid that partitions regions into major and minor. The performances of the proposed methods are compared with the conventional hierarchical path search method in which a region is formed by the boundary line of nearest 4 points of a major node in terms of the path search time and the accuracy. The results obtained from the experiments show that the method based on voronoi achieves short execution time and the method based grid achieves high accuracy.

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A Self-Deployment Scheme Using Improved Potential Field in Mobile Sensor Networks (이동 센서 네트워크에서 개선된 포텐셜 필드를 사용한 자율 배치 방법)

  • Lee, Heon-Jong;Kim, Yong-Hwan;Han, Youn-Hee;Jeong, Young-Sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.1B
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    • pp.106-116
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    • 2010
  • Sensor deployment makes an effect on not only covering of the interesting area but also reliable data acquisition and efficient resource management of sensor, so that sensors must be deployed at their better place. In traditional static wireless sensor networks, however, it is impossible to deploy the sensors manually when they are distributed in unexploited, hostile, or disaster areas. Therefore, if each sensor has locomotion capability, it can re-deploy itself using the location information of neighbor sensors. In our previous study, we showed that moving sensors to the centroids of their Voronoi polygon is efficient for extending the coverage area. In this paper, we present an improved potential-field-based sensor self-deployment scheme by combining the centroid of Voronoi polygon with the traditional potential-field scheme. Simulation results show that our scheme can achieve higher coverage in shorter time and less movement than the traditional potential-field scheme.

Improved Euclidean transform method using Voronoi diagram (보로노이 다이어그램에 기반한 개선된 유클리디언 거리 변환 방법)

  • Jang Seok Hwan;Park Yong Sup;Kim Whoi Yul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.12C
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    • pp.1686-1691
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    • 2004
  • In this paper, we present an improved method to calculate Euclidean distance transform based on Guan's method. Compared to the conventional method, Euclidean distance can be computed faster using Guan's method when the number of feature pixels is small; however, overall computational cost increases proportional to the number of feature pixels in an image. To overcome this problem, we divide feature pixels into two groups: boundary feature pixels (BFPs) and non-boundary feature pixels (NFPs). Here BFPs are defined as those in the 4-neighborhood of foreground pixels. Then, only BFPs are used to calculate the Voronoi diagram resulting in a Euclidean distance map. Experimental results indicate that the proposed method takes 40 Percent less computing time on average than Guan's method. To prove the performance of the proposed method, the computing time of Euclidean distance map by proposed method is compared with the computing time of Guan's method in 16 images that are binary and the size of 512${\times}$512.

Optimal Arrangement of Patrol Ships based on k-Means Clustering for Quick Response of Marine Accidents (해양사고 신속대응을 위한 k-평균 군집화 기반 경비함정 최적배치)

  • Yoo, Sang-Lok;Jung, Cho-Young
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.7
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    • pp.775-782
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    • 2017
  • The position of existing patrol ships has been decided according to subjective judgments, not purely by any reasonable or scientific criteria, because of a lack of access to marine accident positions. In this study, the optimal location of patrol ships is quantitatively determined based on historical marine accident data. The study area used included the coastal sea of Pohang in South Korea. In this study, a k-means clustering algorithm was used to derive the location of patrol ships, and then a Voronoi diagram was used to divide the region around each patrol ship. As a result, the average navigation distance for patrol ships was improved by 4.4 nautical miles, and the average arrival time was improved by 13.2 minutes per marine accident. Moreover, if the locations of patrol ships need to be changed flexibly, it will be possible to optimally arrange limited resources using the technique developed in this study to ensure a fast rescue.

Estimation of optimal position of a mobile robot using object recognition and hybrid thinning method (3차원 물체인식과 하이브리드 세선화 기법을 이용한 이동로봇의 최적위치 추정)

  • Lee, Woo-Jin;Yun, Sang-Seok
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.6
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    • pp.785-791
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    • 2021
  • In this paper, we propose a methodology for estimating the optimal traversable destination from the location-based information of the object recognized by the mobile robot to perform the object delivery service. The location estimation process is to apply the generalized Voronoi graph to the grid map to create an initial topology map composed of nodes and links, recognize objects and extract location data using RGB-D sensors, and collect the shape and distance information of obstacles. Then, by applying the hybrid approach that combines the center of gravity and thinning method, the optimal moving position for the service robot to perform the task of grabbing is estimated. And then, the optimal node information for the robot's work destination is updated by comparing the geometric distance between the estimated position and the existing node according to the node update rule.

Tile Mosaics Preserving Details - 2 Layered Tile Mosaics (세부 묘사를 유지하는 타일 모자이크 - 두 층 타일 모자이크)

  • Kang, Dong-Wann;Yoon, Kyung-Hyun
    • 한국HCI학회:학술대회논문집
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    • 2006.02a
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    • pp.800-806
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    • 2006
  • 최근, 컴퓨터 사이언스 분야에서 모자이크에 대한 다양한 연구들이 이뤄지고 있지만, 세부 묘사를 유지하려는 관점에서의 접근은 부족한 편이다. 본 논문은 원 영상의 세부 묘사를 유지하는 타일 모자이크 방법을 제안한다. 이 방법은 타일간의 빈 공간을 제거하기 위한 겹쳐진 타일의 사용을 통해 구현된다. 본 논문에서 제시한 방법은 다음 세 단계로 구성된다. 첫째, 에지 회피 기법이 적용된 무게중심 보로노이 다이어그램(CVD:Centroidal Voronoi Diagram)을 통해 메인 타일의 위치를 얻는다. 둘째, 메인 타일들의 위치에 딜로니 삼각형화(Delaunay Triangulation)를 적용해 서브 타일의 위치를 계산한다. 셋째, 타일간의 관계를 고려해 타일의 크기와 방향성을 구한다. 위의 과정을 통해 타일 간의 빈 공간이 최소화되어 세부 묘사가 강화된 모자이크 영상을 얻는다.

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Edge-flipping algorithm for computing the circle set Voronoi diagram (원 집합의 보로노이 다이어그램을 구하는 모서리 플립 알고리듬)

  • Kim Donguk;Kim Deok-Soo;Sugihara Kokichi
    • Proceedings of the Society of Korea Industrial and System Engineering Conference
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    • 2002.05a
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    • pp.467-472
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    • 2002
  • Presented in this paper is an algorithm to compute the Voronoi diagram of a circle set from the Voronoi diagram of a point set. The circles are located in Euclidean plane, the radii of the circles are non-negative and not necessarily equal, and the circles are allowed to intersect each other. The idea of the algorithm is to use the topology of the point set Voronoi diagram as a seed so that the correct topology of the circle set Voronoi diagram can be obtained through a number of edge flipping operations. Then, the geometries of the Voronoi edges of the circle set Voronoi diagram are computed. The main advantages of the proposed algorithm are in its robustness, speed, and the simplicity in its concept as well as implementation.

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A Microstructural Analysis for Preventive Treatments of Vertebral Fracture (척추 골절의 예방적 치료법에 관한 미세 구조해석)

  • 김형도;탁계래;김한성;이성재
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.146-149
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    • 2002
  • It is reported that the mechanical properties of vertebral trabecular bone depend on the density and the mass of bones. Osteoporosis is a systemic skeletal disease caused by low bone mass and microstructure deterioration of trabecular bone. Silva and Gibson (1997) studied the treatment of age-related bone loss using drug therapy. Vertebroplasty is a minimally invasive surgery for the treatment of osteoporosis vertebrae. This procedure includes puncturing vertebrae and filling with Polymethylmethacrylate (PMMA). However, the relative effect of drug therapy and bone cement for osteoporosis treatment is not reported yet. In this study, several 2D models of human vertebral trabecular bone are analyzed by finite element method. The mechanical behaviors of the vertebral trabecular bone treated by the drug therapy and the bone cement are compared. This study shows that bone cement treatment is more effective strategy than drug therapy to prevent the degradation of bone strength.

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Edge Tracing Algorithm for Computation of Euclidean Voronoi Diagram for Protein and its Applications (3차원에서 단백질의 보로노이 다이아그램 계산을 위한 모서리추적 알고리즘 및 응용)

  • Jo, Yeong-Song;Kim, Dong-Uk;Jo, Cheol-Hyeong;Kim, Deok-Su
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2005.05a
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    • pp.842-847
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    • 2005
  • Although there are many applications of Euclidean Voronoi diagram for spheres in a 3D space in various disciplines from sciences and engineering, it has not been studied as much as it deserves. In this paper, we present an edge-tracing algorithm to compute the Euclidean Voronoi diagram of 3-dimensional spheres in O(mn) in the worst-case, where m is the number of edges of Voronoi diagram and n is the number of spheres. After building blocks for the algorithm, we show an example of Voronoi diagram for atoms using actual protein data and discuss its applications for protein analysis.

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