• Title/Summary/Keyword: 그리디 알고리즘

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Ant Colony System for solving the traveling Salesman Problem Considering the Overlapping Edge of Global Best Path (순회 외판원 문제를 풀기 위한 전역 최적 경로의 중복 간선을 고려한 개미 집단 시스템)

  • Lee, Seung-Gwan;Kang, Myung-Ju
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.3
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    • pp.203-210
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    • 2011
  • Ant Colony System is a new meta heuristics algorithms to solve hard combinatorial optimization problems. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem. In this paper, we propose the searching method to consider the overlapping edge of the global best path of the previous and the current. This method is that we first determine the overlapping edge of the global best path of the previous and the current will be configured likely the optimal path. And, to enhance the pheromone for the overlapping edges increases the probability that the optimal path is configured. Finally, the performance of Best and Average-Best of proposed algorithm outperforms ACS-3-opt, ACS-Subpath and ACS-Iter algorithms.

The Effect of Multiagent Interaction Strategy on the Performance of Ant Model (개미 모델 성능에서 다중 에이전트 상호작용 전략의 효과)

  • Lee Seung-Gwan
    • The Journal of the Korea Contents Association
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    • v.5 no.3
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    • pp.193-199
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    • 2005
  • One of the important fields for heuristics algorithm is how to balance between Intensificationand Diversification. Ant Colony System(ACS) is a new meta heuristics algorithm to solve hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem(TSP). In this paper, we propose Multi Colony Interaction Ant Model that achieves positive negative interaction through elite strategy divided by intensification strategy and diversification strategy to improve the performance of original ACS. And, we apply multi colony interaction ant model by this proposed elite strategy to TSP and compares with original ACS method for the performance.

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Performance Improvement of Cooperating Agents through Balance between Intensification and Diversification (강화와 다양화의 조화를 통한 협력 에이전트 성능 개선에 관한 연구)

  • 이승관;정태충
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.40 no.6
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    • pp.87-94
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    • 2003
  • One of the important fields for heuristic algorithm is how to balance between Intensification and Diversification. Ant Colony Optimization(ACO) is a new meta heuristic algorithm to solve hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as Breedy search It was first Proposed for tackling the well known Traveling Salesman Problem(TSP). In this paper, we deal with the performance improvement techniques through balance the Intensification and Diversification in Ant Colony System(ACS). First State Transition considering the number of times that agents visit about each edge makes agents search more variously and widen search area. After setting up criteria which divide elite tour that receive Positive Intensification about each tour, we propose a method to do addition Intensification by the criteria. Implemetation of the algorithm to solve TSP and the performance results under various conditions are conducted, and the comparision between the original An and the proposed method is shown. It turns out that our proposed method can compete with the original ACS in terms of solution quality and computation speed to these problem.

Viewing Path Search and Congestion Control Algorithms For Comfortable Museum Viewing (편안한 박물관 관람을 위한 관람 경로 탐색 및 혼잡제어 알고리즘)

  • Seo, Yoon-Deuk;Ahn, Jin-Ho
    • Journal of Internet Computing and Services
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    • v.11 no.3
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    • pp.131-137
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    • 2010
  • Today, many museums are changing their forms with ubiquitous environment. Unlike traditional museums providing only static text-based information attached to its corresponding artifacts to visitors, those ubiquitous museums provide not only artifacts' text information, but also many different forms of information such as sound or media through personal digital assistance or cell phones. However, these existing ubiquitous museums still provide each visitor only with artifact-centric information in very simple ways. Also this disadvantageous feature causes high gallery congestion problem resulting from providing a uniform path for every visitor. These limitations may be the biggest barrier to providing more various and useful information about artifacts to visitors through considering each visitor's preference. This paper propose a new optimal viewing path search algorithm to provide comfortable museum viewing for each visitor according to its preference. Also, a new congestion control method is developed to protect visitors from being put in some hot spots on their museum viewing, improving its comfort to a maximum.

A Method of Image Matching by 2D Alignment of Unit Block based on Comparison between Block Content (단위블록의 색공간 내용비교 기반 2차원 블록정렬을 이용한 이미지 매칭방법)

  • Jang, Chul-Jin;Cho, Hwan-Gue
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.8
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    • pp.611-615
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    • 2009
  • Due to the popular use of digital camera, a great number of photos are taken at every usage of camera. It is essential to reveal relationship between photos to manage digital photos efficiently. We propose a method that tessellates image into unit blocks and applies 2D alignment to extend content-based similar region from seed block pair having high similarity. Through an alignment, we can get a block region scoring best matching value on whole image. The method can distinguish whether photos are sharing the same object or background. Our result is less sensitive to transition or pause change of objects. In experiment, we show how our alignment method is applied to real photo and necessities for further research like photo clustering and massive photo management.

Minimum Cost Path for Private Network Design (개인통신망 설계를 위한 최소 비용 경로)

  • Choe, Hong-Sik;Lee, Ju-Yeong
    • Journal of KIISE:Computer Systems and Theory
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    • v.26 no.11
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    • pp.1373-1381
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    • 1999
  • 이 논문에서는 통신망 설계 응용분야의 문제를 그래프 이론 문제로써 고려해 보았다. 개별 기업체가 서로 떨어진 두 곳을 연결하고자 할 때 공용통신망의 회선을 빌려 통신망을 구축하게 되는데 많은 경우 여러 종류의 회선들이 공급됨으로 어떤 회선을 선택하느냐의 문제가 생긴다. 일반적으로 빠른 회선(low delay)은 느린 회선(high delay)에 비해 비싸다. 그러나 서비스의 질(Quality of Service)이라는 요구사항이 종종 종단지연(end-to-end delay)시간에 의해 결정되므로, 무조건 낮은 가격의 회선만을 사용할 수는 없다. 결국 개별 기업체의 통신망을 위한 통로를 공용 통신망 위에 덮어씌워(overlaying) 구축하는 것의 여부는 두 개의 상반된 인자인 가격과 속도의 조절에 달려 있다. 따라서 일반적인 최소경로 찾기의 변형이라 할 수 있는 다음의 문제가 본 논문의 관심사이다. 두 개의 지점을 연결하는데 종단지연시간의 한계를 만족하면서 최소경비를 갖는 경로에 대한 해결을 위하여, 그래프 채색(coloring) 문제와 최단경로문제를 함께 포함하는 그래프 이론의 문제로 정형화시켜 살펴본다. 배낭문제로의 변환을 통해 이 문제는 {{{{NP-complete임을 증명하였고 {{{{O($\mid$E$\mid$D_0 )시간에 최적값을 주는 의사선형 알고리즘과O($\mid$E$\mid$)시간의 근사 알고리즘을 보였다. 특별한 경우에 대한 {{{{O($\mid$V$\mid$ + $\mid$E$\mid$)시간과 {{{{O($\mid$E$\mid$^2 + $\mid$E$\mid$$\mid$V$\mid$log$\mid$V$\mid$)시간 알고리즘을 보였으며 배낭 문제의 해결책과 유사한 그리디 휴리스틱(greedy heuristic) 알고리즘이 그물 구조(mesh) 그래프 상에서 좋은 결과를 보여주고 있음을 실험을 통해 확인해 보았다.Abstract This paper considers a graph-theoretic problem motivated by a telecommunication network optimization. When a private organization wishes to connect two sites by leasing physical lines from a public telecommunications network, it is often the cases that several categories of lines are available, at different costs. Typically a faster (low delay) lines costs more than a slower (high delay) line. However, low cost lines cannot be used exclusively because the Quality of Service (QoS) requirements often impose a bound on the end-to-end delay. Therefore, overlaying a path on the public network involves two diametrically opposing factors: cost and delay. The following variation of the standard shortest path problem is thus of interest: the shortest route between the two sites that meets a given bound on the end-to-end delay. For this problem we formulate a graph-theoretical problem that has both a shortest path component as well as coloring component. Interestingly, the problem could be formulated as a knapsack problem. We have shown that the general problem is NP-complete. The optimal polynomial-time algorithms for some special cases and one heuristic algorithm for the general problem are described.

A Method to Decide the Number of Additional Edges and Their Locations to Integrate the Communities by Using Fitness Function (적합도 함수를 이용한 커뮤니티 통합에 필요한 추가에지수 결정 및 위치 선정 방법)

  • Jun, Byung-Hyun;Lee, Sang-Hoon;Han, Chi-Geun
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.12
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    • pp.239-246
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    • 2014
  • In this paper, we propose a method to decide the additional edges in order to integrate two communitites A,B($${\mid}A{\mid}{\geq_-}{\mid}B{\mid}$$, ${\mid}{\cdot}{\mid}$ is the size of the set). The proposed algorithm uses a fitness function that shows the property of a community and the fitness function is defined by the number of edges which exist in the community and connect two nodes, one is in the community and the other is out of the community. The community has a strong property when the function has a large value. The proposed algorithm is a kind of greedy method and when a node of B is merged to A, the minimum number of additional edges is decided to increase the fitness function value of A. After determining the number of additional edges, we define the community connectivity measures using the node centrality to determine the edges locations. The connections of the new edges are fixed to maximize the connectivity measure of the combined community. The procedure is applied for all nodes in B to integrate A and B. The effectiveness of the proposed algorithm is shown by solving the Zachary Karate Club network.

Extraction and Revision of Building Information from Single High Resolution Image and Digital Map (단일 고해상도 위성영상과 수치지도로부터 건물 정보 추출 및 갱신)

  • Byun, Young-Gi;Kim, Hye-Jin;Choi, Jae-Wan;Han, You-Kyung;Kim, Yong-Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.2
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    • pp.149-156
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    • 2008
  • In this paper, we propose a method aiming at updating the building information of the digital maps using single high resolution satellite image and digital map. Firstly we produced a digital orthoimage through the automatic co-registration of QuickBird image and 1:1,000 digital map. Secondly we extracted building height information through the template matching of digital map's building vector data and the image's edges obtained by Canny operator. Finally we refined the shape of some buildings by using the result from template matching as the seed polygon of the greedy snake algorithm. In order to evaluate the proposed method's effectiveness, we estimated accuracy of the extracted building information using LiDAR DSM and 1:1,000 digital map. The evaluation results showed the proposed method has a good potential for extraction and revision of building information.

Reference Node Selection Scheme for Estimating Relative Locations of Mobile Robots (이동 로봇의 상대위치 추정을 위한 기준노드 선택 기법)

  • Ha, Taejin;Kim, Sunyong;Park, Sun Young;Kwon, Daehoon;Ham, Jaehyun;Lim, Hyuk
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.4
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    • pp.508-516
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    • 2016
  • When GPS signals are not available, a relative localization can be alternatively used to represent the topological relationship between mobile nodes. A relative location map of a network can be constructed by using the distance information between all the pairs of nodes in the network. If a network is large, a number of small local maps are individually constructed and are merged to obtain the whole map. However, this approach may result in a high computation and communication overhead. In this paper, we propose a reference-node selection scheme for relative localization map construction, which chooses a subset of nodes as a reference node that is supposed to construct local maps. The scheme is a greedy algorithm that iteratively chooses nodes with high degree as a reference node until the chosen local maps are successfully merged with a sufficient number of common nodes between nearby local maps. The simulation results indicate that the proposed scheme achieves higher localization accuracy with a reduced computational overhead.

Multi Colony Ant Model using Positive.Negative Interaction between Colonies (집단간 긍정적.부정적 상호작용을 이용한 다중 집단 개미 모델)

  • Lee, Seung-Gwan;Chung, Tae-Choong
    • The KIPS Transactions:PartB
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    • v.10B no.7
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    • pp.751-756
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    • 2003
  • Ant Colony Optimization (ACO) is new meta heuristics method to solve hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was firstly proposed for tackling the well known Traveling Salesman Problem (TSP) . In this paper, we introduce Multi Colony Ant Model that achieve positive interaction and negative interaction through Intensification and Diversification to improve original ACS performance. This algorithm is a method to solve problem through interaction between ACS groups that consist of some agent colonies to solve TSP problem. In this paper, we apply this proposed method to TSP problem and evaluates previous method and comparison for the performance and we wish to certify that qualitative level of problem solution is excellent.