• Title/Summary/Keyword: 인접행렬

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A Study of Routing based on Adjacency Matrix in Ad hoc Networks (애드 혹 네트워크에서 인접 행렬 기반의 라우팅 연구)

  • Lee, Sung-Soo;Kim, Jeong-Mi;Park, Hee-Joo;Kim, Chong-Gun
    • The KIPS Transactions:PartC
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    • v.15C no.6
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    • pp.531-538
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    • 2008
  • With the dynamic and mobile nature of ad hoc networks, links may fail due to topology changes. So, a major challenge in ad hoc network is dynamically to search paths from a source to destination with an efficient routing method, which is an important issue for delay-sensitive real-time application. The main concerns of graph theory in communications are finding connectivity and searching paths using given nodes. A topology of the nodes in ad hoc networks can be modeled as an adjacency matrix. In this paper, based on this adjacency matrix, we propose new path search algorithms using a sequence of matrix calculation. The proposed algorithms can search paths from a destination to a source using connectivity matrix. Two matrix-based algorithms for two different purposes are proposed. Matrix-Based Backward Path Search(MBBS) algorithm is designed for shortest path discovery and Matrix-Based Backward Multipath Search(MBBMS) algorithm is for multipath search.

Determination of Minimum Spacing between Off-ramp Terminus and Intersection Considering the Influence of Adjacent Signalized Intersections (신호교차로 영향에 따른 도시고속도로 유출연결로 최소이격거리에 관한 연구)

  • Kim, Sang-Gu;Sim, Dae-Yeong;Heo, Du-Wan
    • Journal of Korean Society of Transportation
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    • v.25 no.4
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    • pp.79-87
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    • 2007
  • The interchanges of urban freeways have many problems with traffic operation due to high off-ramp flows and frequent congestion at adjacent intersections. The flow exiting from off-ramps is affected by the operational status and traffic volume conditions of the nearest signalized intersection. As a result, off-ramp flow cannot exit and the queue backs up the freeway mainline when queues from the signalized intersection form up to the junction of the off-ramp and street. The spacing between an off-ramp and an adjacent intersection is likely to determine the traffic conditions at the adjacent intersection. However, the current design guidelines do not consider such a factor. This study is to develop a model calculating the spacing between off-ramps and adjacent intersections considering the signal, traffic, and road conditions. The variables affecting the model in this study are effective green time (g/C), volume-capacity ratio (v/c), the number of lanes, and off-ramp volume. Various scenarios are designed to represent the effects of the variables and the road networks are constructed using VISSIM, which is a common traffic micro-simulation software package. The queue length is derived from VISSIM and this length is considered as the recommended spacing between the off-ramp and the adjacent intersection. Through the simulation analysis, regression models are developed to calculate the queue length reflecting the various conditions such as signals, traffic, and road configurations. The developed model can be used to create road design guidelines to determine the location of off-ramps in the planning stage.

Fault-Tolerant Algorithm using Multi-Connectivity of Communication Networks (통신망의 다중연결성을 이용한 결함허용 알고리즘)

  • Moon, Yun-Ho;Kim, Byung-Ki
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.1
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    • pp.53-60
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    • 2000
  • The purpose of this paper is to propose new recovery algorithm for case of a system element raises communication obstacle due to faults in networks, Also we are simulate the algorithm using adjacency matrix. We recover one faulty node per each excution of proposed algorithm so that we can be reconstruct the faulty system gradually to communicatable network. For that, this paper propose a new recovery algorithm named MATRECO which connect the recovery process is simulated by use of adjacency matrix.

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Nearest-Neighbor Collaborative Filtering Using Dimensionality Reduction by Non-negative Matrix Factorization (비부정 행렬 인수분해 차원 감소를 이용한 최근 인접 협력적 여과)

  • Ko, Su-Jeong
    • The KIPS Transactions:PartB
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    • v.13B no.6 s.109
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    • pp.625-632
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    • 2006
  • Collaborative filtering is a technology that aims at teaming predictive models of user preferences. Collaborative filtering systems have succeeded in Ecommerce market but they have shortcomings of high dimensionality and sparsity. In this paper we propose the nearest neighbor collaborative filtering method using non-negative matrix factorization(NNMF). We replace the missing values in the user-item matrix by using the user variance coefficient method as preprocessing for matrix decomposition and apply non-negative factorization to the matrix. The positive decomposition method using the non-negative decomposition represents users as semantic vectors and classifies the users into groups based on semantic relations. We compute the similarity between users by using vector similarity and selects the nearest neighbors based on the similarity. We predict the missing values of items that didn't rate by a new user based on the values that the nearest neighbors rated items.

Subquadratic Time Algorithm to Find the Connected Components of Circle Graphs (원 그래프의 연결 요소들을 찾는 제곱미만 시간 알고리즘)

  • Kim, Jae-hoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.11
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    • pp.1538-1543
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    • 2018
  • For n pairs of points (a,b) on a circle, the line segment to connect two points is called a chord. These chords define a new graph G. Each chord corresponds to a vertex of G, and if two chords intersect, the two vertices corresponding to them are connected by an edge. This makes a graph, called by a circle graph. In this paper, we deal with the problem to find the connected components of a circle graph. The connected component of a graph G is a maximal subgraph H such that any two vertices in H can be connected by a path. When the adjacent matrix of G is given, the problem to find them can be solved by either the depth-first search or the breadth-first search. But when only the information for the chords is given as an input, it takes ${\Omega}(n^2)$ time to obtain the adjacent matrix. In this paper, we do not make the adjacent matrix and develop an $O(n{\log}^2n)$ algorithm for the problem.

A Study on Image Compression Using Laplacian Pyramid Encoding (라플라시안 피라미드 부호화에 의한 영상 압축에 관한 연구)

  • 박유경;박지환
    • Proceedings of the Korea Multimedia Society Conference
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    • 2000.11a
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    • pp.175-178
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    • 2000
  • 인접한 화소들간의 상관성에 대한 오류 정보만을 추출하여 전송하는 기법인 라플라시안 피라미드는 알고리즘 구성이 간단하며, 낮은 엔트로피 전송이 가능한 무손실 예측 압축과 점진적인 전송이 가능한 이점을 가지고 있다. 이러한 라플라시안 피라미드를 효율적으고 구성하기 위하여 기존의 5$\times$5 가중치 행렬을 3$\times$3 가중치 행렬로 구성하는 새로운 기법을 보인다. 3$\times$3 가중치행렬을 이용하는 방법이 5$\times$5 가중치 행렬에 의한 알고리즘의 구성보다 간단하면서도 압축효율이 좋음을 시뮬레이션을 통하여 보인다.

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A Historical Background of Graph Theory and the Computer Representation (그래프 이론의 역사적 배경과 그 컴퓨터 표현)

  • Kim Hwa-jun;Han Su-young
    • Journal for History of Mathematics
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    • v.18 no.1
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    • pp.103-110
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    • 2005
  • This paper is aimed at studying a historical background of graph theory and we deal with the computer representation of graph through a simple example. Graph is represented by adjacency matrix, edge table, adjacency lists and we study the matrix representation by Euler circuit. The effect of the matrix representation by Euler circuit economize the storage capacity of computer. The economy of a storage capacity has meaning on a mobile system.

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Development of Exit-Ramp Control Strategy Avoiding Mainline Spillover for Urban Freeway (과포화 신호제어 기법을 응용한 도시고속도로 진출램프 제어전략의 개발)

  • 김영찬;이철기;허혜정
    • Journal of Korean Society of Transportation
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    • v.19 no.3
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    • pp.89-100
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    • 2001
  • 내부순환로의 진출램프 중 성산, 홍은, 홍제, 길음, 마장 진출램프에서는 램프의 지체가 심각하여, 진출차량의 대기행렬이 내부순환로 본선에까지 이르는 대기행렬 역류현상이 발생하고 있다. 이러한 본선으로의 대기행렬 역류는 본선의 혼잡을 가중시키고 교통사고의 위험도 증가시킨다. 본 논문에서는 이러한 도시고속도로의 진출램프 혼잡을 개선하기 위해 진출램프 제어전략을 개발하였다. 진출램프 제어전략의 목표는 진출램프의 대기차량이 본선으로 역류하지 않도록 하는 것이다. 대기행렬의 역류를 막기 위해서는 진출램프의 차량이 인접한 간선도로로 원활하게 진행하도록 해야 하며, 간선도로와 진출램프의 대기행렬을 제어정책에 따라 관리할 수 있어야 한다. 이를 위해서 진출램프 진출부에 신호를 설치하여 간선도로차량의 흐름을 제어하고, 진출부 하류부 교차로와 연동제어를 하여 진출공간을 확보하였다. 또한, 대기행렬의 관리를 위해서는 대기행렬 관리계수를 정의하고 이 값에 따라 현시를 결정할 수 있는 제어식을 유도하였다. 진출램프 제어전략은 과포화 신호제어 기법을 응용하여 개발하였으며, 그 중 Equity offset과 내부미터링 기법을 연동제어에 응용하였고, Imbalanced split 기법은 대기행렬 관리계수에 따라 현시가 결정되는 제어식의 개발에 응용하였다. 진출램프 제어전략을 평가하기 위하여 진출램프의 혼잡으로 인해 본선으로 대기행렬 역류가 발생하는 내부순환로의 홍은, 홍제 진출램프를 선정하였으며, NETSIM을 통해 진출램프 제어전략의 효과를 분석하였다. 분석결과 진출램프의 혼잡이 크게 개선되며, 운영자의 관리목적에 따라 대기행렬의 관리가 이루어지는 것을 볼 수 있었다. 진출램프 제어전략은 내부순환 도시고속도로뿐만 아니라 진출램프 제어가 필요한 타도시고속도로에서도 적용을 하면 좋은 효과를 얻을 수 있을 것으로 예상된다.

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Study on a System Reliability Calculation Method Using Failure Enumeration of Reliability Path (신뢰도 경로의 고장열거를 이용한 시스템 신뢰도 계산방법 연구)

  • Lee, Jang-Il;Park, Kee-Jun;Chun, Hwan-Kyu;Jeong, Choong-Min;Shin, Dong-Jun;Suh, Myung-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.6
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    • pp.629-633
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    • 2011
  • Recently, systems such as aircraft, trains and ships have become larger more complex. Therefore, the reliability calculation of these systems is more difficult. This paper presents a reliability calculation algorithm for a complex system with a solution that is difficult to analyze. When the system has a very complex structure, it is very difficult to find an analytical solution. In this case, we can assess system reliability using the failure enumeration method of the reliability path. In this research, we represent the reliability block diagram by an adjacent matrix and define the reliability path. We can find any system status by the failure enumeration of the reliability path, and thus we can calculate any kind of system reliability through this process. This result can be applied to RCM (Reliability-Centered Maintenance) and reliability information-management systems, in which the system reliability is composed of the reliabilities of individual parts.

Empirical Bayes Estimation and Comparison of Credit Migration Matrices (신용등급전이행렬의 경험적 베이지안 추정과 비교)

  • Kim, Sung-Chul;Park, Ji-Yeon
    • The Korean Journal of Applied Statistics
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    • v.22 no.3
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    • pp.443-461
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    • 2009
  • In order to overcome the lack of Korean credit rating migration data, we consider an empirical Bayes procedure to estimate credit rating migration matrices. We derive the posterior probabilities of Korean credit rating transitions by utilizing the Moody's rating migration data and the credit rating assignments from Korean rating agency as prior information and likelihood, respectively. Metrics based upon the average transition probability are developed to characterize the migration matrices and compare our Bayesian migration matrices with some given matrices. Time series data for the metrics show that our Bayesian matrices are stable, while the matrices based on Korean data have large variation in time. The bootstrap tests demonstrate that the results from the three estimation methods are significantly different and the Bayesian matrices are more affected by Korean data than the Moody's data. Finally, Monte Carlo simulations for computing the values of a portfolio and its credit VaRs are performed to compare these migration matrices.