• Title/Summary/Keyword: Routing path optimization

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An Optimization Approach to Routing and Wavelength Assignment in WDM All-Optical Mesh Networks without Wavelength Conversion

  • Lee, Kyung-Sik;Kang, Kug-Chang;Lee, Tae-Han;Park, Sung-Soo
    • ETRI Journal
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    • v.24 no.2
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    • pp.131-141
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    • 2002
  • This paper considers a routing and wavelength assignment problem (RWAP) for the implementation of efficient Wavelength Division Multiplexing all-optical mesh networks without wavelength conversion. For a given physical network and required connections, the solution to the RWAP consists in how to select a suitable path and wavelength among the many possible choices for each connection so that no two paths using the same wavelength pass through the same link, while minimizing the number of required wavelengths. We introduce an integer programming formulation of the RWAP, which has an exponential number of variables, and propose an algorithm to solve it based on the column generation technique. The proposed algorithm can yield high quality solutions and tight lower bounds at the same time. Though the proposed algorithm cannot guarantee optimal solutions, computational results show that the algorithm yields provably good solutions within a reasonable time.

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A Study on Voltage Stability Improvement by the Efficient Network Reconfiguration Algorithm

  • Kim, Byung-Seop;Shin, Joong-Rin;Park, Jong-Bae;Shin, Yong-Hak
    • KIEE International Transactions on Power Engineering
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    • v.4A no.2
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    • pp.58-68
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    • 2004
  • This paper presents an optimal routing algorithm (ORA) for maximizing voltage stability as well as for minimizing power loss in radial power systems. In the proposed ORA, a novel voltage stability index (VSI) for real-time assessment is newly introduced based on the conventional critical transmission path framework. In addition, the suggested algorithm can automatically detect the critical transmission paths resulting in voltage collapse when additional real or reactive loads are added. To implement an effective ORA, we have developed an improved branch exchange (IBE) method based on a loss calculation index and tie-branch power flow equations, which are suggested for real-time applications. The proposed algorithm has been tested with IEEE test systems as well as a large-scale power system in Korea to demonstrate its effectiveness and efficiency.

Routing Protocol for Wireless Sensor Networks Based on Virtual Force Disturbing Mobile Sink Node

  • Yao, Yindi;Xie, Dangyuan;Wang, Chen;Li, Ying;Li, Yangli
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.4
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    • pp.1187-1208
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    • 2022
  • One of the main goals of wireless sensor networks (WSNs) is to utilize the energy of sensor nodes effectively and maximize the network lifetime. Thus, this paper proposed a routing protocol for WSNs based on virtual force disturbing mobile Sink node (VFMSR). According to the number of sensor nodes in the cluster, the average energy and the centroid factor of the cluster, a new cluster head (CH) election fitness function was designed. At the same time, a hexagonal fixed-point moving trajectory model with the best radius was constructed, and the virtual force was introduced to interfere with it, so as to avoid the frequent propagation of sink node position information, and reduce the energy consumption of CH. Combined with the improved ant colony algorithm (ACA), the shortest transmission path to Sink node was constructed to reduce the energy consumption of long-distance data transmission of CHs. The simulation results showed that, compared with LEACH, EIP-LEACH, ANT-LEACH and MECA protocols, VFMSR protocol was superior to the existing routing protocols in terms of network energy consumption and network lifetime, and compared with LEACH protocol, the network lifetime was increased by more than three times.

A Study on Applying Genetic Algorithm for Optimum Virtual Path Network Design in ATM Network (ATM 망에서 최적 가상 경로망 설계를 위한 유전자 알고리즘 응용에 관한 연구)

  • 강주락;권기호
    • Proceedings of the IEEK Conference
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    • 2000.06c
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    • pp.31-34
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    • 2000
  • Genetic Algorithm is well known as the efficient algorithm which can solve a difficult optimization problem. Recently, there has been increasing interest in applying genetic algorithm to problem related to network design. In this paper, we propose a two-step genetic algorithm for designing a optimum virtual path network(VPN) for a given physical network and traffic demand. The first step is a routing step in which a route is found between every node pair in the network. In the second step, paths are assigned as VPs so as to minimize the total number of VPs configured, the number of VPs carried by a link, and the VP hopcount. We study the performance of the propose algorithm through simulation. The result shows that the VPN generated by the proposed algorithm is good in minimizing the number of VPs configured, the load on a link, and the VP hopcount.

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Routing Service Implementation using a Dual Graph (듀얼 그래프를 이용한 라우팅 서비스 구현)

  • 김성수;허태욱;박종현;이종훈
    • Proceedings of the IEEK Conference
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    • 2003.11b
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    • pp.171-174
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    • 2003
  • Shortest path problems are among the most studied network flow optimization problems, with interesting applications in various fields. One such field is the route determination service, where various kinds of shortest path problems need to be solved in location-based service. Our research aim is to propose a route technique in real-time location-based service (LBS) environments according to user's route preferences such as shortest, fastest, easiest and so on. Turn costs modeling and computation are important procedures in route planning. We propose a new rest modeling method for turn costs which are traditionally attached to edges in a graph. Our proposed route determination technique also has an advantage that can provide service interoperability by implementing XML web service for the OpenLS route determination service specification.

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Complexity Results for the Design Problem of Content Distribution Networks

  • Choi, Byung-Cheon;Chung, Jibok
    • Management Science and Financial Engineering
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    • v.20 no.2
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    • pp.7-12
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    • 2014
  • Content Delivery Network (CDN) has evolved to overcome a network bottleneck and improve user perceived Quality of Service (QoS). A CDN replicates contents from the origin server to replica servers to reduce the overload of the origin server. CDN providers would try to achieve an acceptable performance at the least cost including the storage space or processing power. In this paper, we introduce a new optimization model for the CDN design problem considering the user perceived QoS and single path (non-bifurcated) routing constraints and analyze the computational complexity for some special cases.

Using Genetic Algorithms for Routing Metric in Wireless Mesh Network (무선 메쉬 네트워크에서 유전 알고리즘을 이용한 라우팅 메트릭 기법)

  • Yoon, Chang-Pyo;Shin, Hyo-Young;Ryou, Hwang-Bin
    • Convergence Security Journal
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    • v.11 no.1
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    • pp.11-18
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    • 2011
  • Wireless mesh network technology with transmission speeds similar to wired and wireless technology means to build, compared with wired networks, building a more efficient network to provide convenience and flexibility. The wireless mesh network router nodes in the energy impact of the mobility is less constrained and has fewer features entail. However, the characteristics of various kinds due to network configuration settings and the choice of multiple paths that can occur when the system overhead and there are many details that must be considered. Therefore, according to the characteristics of these network routing technology that is reflected in the design and optimization of the network is worth noting. In this paper, a multi-path setting can be raised in order to respond effectively to the problem of the router node data loss and bandwidth according to traffic conditions and links to elements of the hop count evaluation by using a genetic algorithm as a workaround for dynamic routing the routing metric for wireless mesh network scheme is proposed.

An Efficient MPLS Routing System for Supporting QoS and Best-Effort Services (QoS 서비스와 최선형 서비스를 위한 효율적인 MPLS 라우팅 시스템)

  • Jeon, Hahn-Earl;Kim, Sung-Dae;Shin, Yong-Chul;Lee, Jai-Yong;Kim, Hyung-Taek
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.1B
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    • pp.71-79
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    • 2003
  • As the traffic grows rapidly in the Internet, the QoS guarantee of the flows and the traffic engineering problems have become very important issues. MPLS has more advantages to solve the problems than existing IP routing because of its use of multiple paths between the source and destination pairs Particularly, the availability of Constraint-based Shortest Path First(CSPF) algorithm and explicit route in MPLS made the problem referred above to be solved efficiently. However, the CSPF algorithm has the characteristic of selecting the shortest path of all paths which meet the traffics' QoS constraints Therefore, even though there are alternative paths to route traffic, alternate QoS paths may not be found and best-effort traffic will be dropped during congestion period In this paper, we present the network resource optimization method related to the traffic engineering by using load balancing through routing in MPLS network.

Route Optimization Scheme using Routing Protocol in Nested Mobile Networks (중첩된 이동 네트워크환경에서 동적 라우팅 프로토콜을 이용한 경로 최적화 기법)

  • Kim, Eui-Kook;Lee, Jong-Hyup
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.11
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    • pp.1966-1975
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    • 2008
  • NEMO Basic Support Protocol standardized in IETF provides the seamless communication environment to all nodes within the mobile network regardless of the network movement while the network is moving. According to the standard, when the mobile network moves outside of its home network the network can make use of the binding update message or dynamic routing protocol in order to register the mobility information into the Home Agent(HA). But because these two methods don't consider the route optimization, all packets destined to Mobile Network Nodes(MNNs) attached into the Mobile Router(MR) have to go through HAs of MRs so that they bring on the transmission delay and the waste of the bandwidth. This situation is to be worse and causes the packet fragmentation problem if MRs within the mobile network are nested. Even though there have been some researches about the route optimization to recover the problems, they have problems in the packet transmission performance side. In this paper, we propose a new scheme to improve the network performance by using a dynamic routing protocol and minimizing the number of HAs on the end-to-end path. Various performance evaluations show that the proposed mechanism gives better performance in view of the packet transmission compared to the existing schemes.

Intelligent Optimal Route Planning Based on Context Awareness (상황인식 기반 지능형 최적 경로계획)

  • Lee, Hyun-Jung;Chang, Yong-Sik
    • Asia pacific journal of information systems
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    • v.19 no.2
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    • pp.117-137
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    • 2009
  • Recently, intelligent traffic information systems have enabled people to forecast traffic conditions before hitting the road. These convenient systems operate on the basis of data reflecting current road and traffic conditions as well as distance-based data between locations. Thanks to the rapid development of ubiquitous computing, tremendous context data have become readily available making vehicle route planning easier than ever. Previous research in relation to optimization of vehicle route planning merely focused on finding the optimal distance between locations. Contexts reflecting the road and traffic conditions were then not seriously treated as a way to resolve the optimal routing problems based on distance-based route planning, because this kind of information does not have much significant impact on traffic routing until a a complex traffic situation arises. Further, it was also not easy to take into full account the traffic contexts for resolving optimal routing problems because predicting the dynamic traffic situations was regarded a daunting task. However, with rapid increase in traffic complexity the importance of developing contexts reflecting data related to moving costs has emerged. Hence, this research proposes a framework designed to resolve an optimal route planning problem by taking full account of additional moving cost such as road traffic cost and weather cost, among others. Recent technological development particularly in the ubiquitous computing environment has facilitated the collection of such data. This framework is based on the contexts of time, traffic, and environment, which addresses the following issues. First, we clarify and classify the diverse contexts that affect a vehicle's velocity and estimates the optimization of moving cost based on dynamic programming that accounts for the context cost according to the variance of contexts. Second, the velocity reduction rate is applied to find the optimal route (shortest path) using the context data on the current traffic condition. The velocity reduction rate infers to the degree of possible velocity including moving vehicles' considerable road and traffic contexts, indicating the statistical or experimental data. Knowledge generated in this papercan be referenced by several organizations which deal with road and traffic data. Third, in experimentation, we evaluate the effectiveness of the proposed context-based optimal route (shortest path) between locations by comparing it to the previously used distance-based shortest path. A vehicles' optimal route might change due to its diverse velocity caused by unexpected but potential dynamic situations depending on the road condition. This study includes such context variables as 'road congestion', 'work', 'accident', and 'weather' which can alter the traffic condition. The contexts can affect moving vehicle's velocity on the road. Since these context variables except for 'weather' are related to road conditions, relevant data were provided by the Korea Expressway Corporation. The 'weather'-related data were attained from the Korea Meteorological Administration. The aware contexts are classified contexts causing reduction of vehicles' velocity which determines the velocity reduction rate. To find the optimal route (shortest path), we introduced the velocity reduction rate in the context for calculating a vehicle's velocity reflecting composite contexts when one event synchronizes with another. We then proposed a context-based optimal route (shortest path) algorithm based on the dynamic programming. The algorithm is composed of three steps. In the first initialization step, departure and destination locations are given, and the path step is initialized as 0. In the second step, moving costs including composite contexts into account between locations on path are estimated using the velocity reduction rate by context as increasing path steps. In the third step, the optimal route (shortest path) is retrieved through back-tracking. In the provided research model, we designed a framework to account for context awareness, moving cost estimation (taking both composite and single contexts into account), and optimal route (shortest path) algorithm (based on dynamic programming). Through illustrative experimentation using the Wilcoxon signed rank test, we proved that context-based route planning is much more effective than distance-based route planning., In addition, we found that the optimal solution (shortest paths) through the distance-based route planning might not be optimized in real situation because road condition is very dynamic and unpredictable while affecting most vehicles' moving costs. For further study, while more information is needed for a more accurate estimation of moving vehicles' costs, this study still stands viable in the applications to reduce moving costs by effective route planning. For instance, it could be applied to deliverers' decision making to enhance their decision satisfaction when they meet unpredictable dynamic situations in moving vehicles on the road. Overall, we conclude that taking into account the contexts as a part of costs is a meaningful and sensible approach to in resolving the optimal route problem.