• Title/Summary/Keyword: Route

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Damping BGP Route Flaps

  • Duan, Zhenhai;Chandrashekar, Jaideep;Krasky, Jeffrey;Xu, Kuai;Zhang, Zhi-Li
    • Journal of Communications and Networks
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    • v.9 no.4
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    • pp.490-498
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    • 2007
  • BGP route flap damping(RFD) was anecdotally considered to be a key contributor to the stability of the global Internet inter-domain routing system. However, it was recently shown that RFD can incorrectly suppress for substantially long periods of time relatively stable routes, i.e., routes that only fail occasionally. This phenomenon can be attributed to the complex interaction between BGP path exploration and how the RFD algorithm identifies route flaps. In this paper we identify a distinct characteristic of BGP path exploration following a single network event such as a link or router failure. Based on this characteristic, we distinguish BGP route updates during BGP path exploration from route flaps and propose a novel BGP route flap damping algorithm, RFD+. RFD+ has a number of attractive properties in improving Internet routing stability. In particular, it can correctly suppress persistent route flaps without affecting routes that only fail occasionally. In addition to presenting the new algorithm and analyzing its properties, we also perform simulation studies to illustrate the performance of the algorithm.

Simulation of optimal arctic routes using a numerical sea ice model based on an ice-coupled ocean circulation method

  • Nam, Jong-Ho;Park, Inha;Lee, Ho Jin;Kwon, Mi Ok;Choi, Kyungsik;Seo, Young-Kyo
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.5 no.2
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    • pp.210-226
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    • 2013
  • Ever since the Arctic region has opened its mysterious passage to mankind, continuous attempts to take advantage of its fastest route across the region has been made. The Arctic region is still covered by thick ice and thus finding a feasible navigating route is essential for an economical voyage. To find the optimal route, it is necessary to establish an efficient transit model that enables us to simulate every possible route in advance. In this work, an enhanced algorithm to determine the optimal route in the Arctic region is introduced. A transit model based on the simulated sea ice and environmental data numerically modeled in the Arctic is developed. By integrating the simulated data into a transit model, further applications such as route simulation, cost estimation or hindcast can be easily performed. An interactive simulation system that determines the optimal Arctic route using the transit model is developed. The simulation of optimal routes is carried out and the validity of the results is discussed.

A Study on the Evacuation Planning in the Multiplex Cinema (멀티플렉스 영화관의 피난계획에 관한 연구)

  • So Eun-Tark;Song Byung-Ha
    • Korean Institute of Interior Design Journal
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    • v.14 no.3 s.50
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    • pp.147-155
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    • 2005
  • As multiplex theaters are increasing rapidly in number, concerns over the evacuation process in case of fire emergency are also increasing. The study investigates the users' awareness and recognition of evacuation route by the method of questionnaire, and analyzes the users' behavior in choosing the route by the simulation program called Simulex. Among others, findings indicate a vast majority of the users are unaware of the proper route in the emergency, yet anticipate to evacuate by it, instead of the entry/exit route that they are familiar with. This aspect, however, can be useful to provide the proper route of evacuation for the users, if an appropriate information is given that the entry/exit route is also used as an emergency egress. The simulation shows heavy congestion at the closer evacuation route from the exit, and distinctly less traffic at the farther means of egress. Based on this natural phenomenon, it is suggested that the emergency stair should be nearby and aligned with the exit from auditorium. Although the present building regulation only requires a minimum dimension at each route, there is a need to widen the passageway that is likely to be recognized easily and subsequently overcrowded in case of fire emergency.

The Quantification Research of Multi-Factors for Route Determination Using AHP Technique (AHP 기법을 이용한 도로의 노선 선정시 다중인자의 정량화 연구)

  • 양인태;김동문;최승필
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.20 no.2
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    • pp.199-206
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    • 2002
  • The application of GSIS for most route determination is provided by selecting several basic data such as land use, land construction quantity and land price, and then establishing a database to analyze for the route determination. However, this strategy rarely considers the complicated multi-factors that are essential for route determination. To solve this problem, it is required to use the GSIS and attempt to support the decision of majority for optimum route determination and standardize the route determination procedure. Accordingly, in this study, the qualification of multi-factors was attempted using the AHP technique, and so the data for the route determination was provided effectively, which resulted in the optimum route determination. As a result of applying the AHP technique, optimum routes were selected more rationally than randomly applying the values of multi-factors as before.

A New Route Optimization Scheme for Network Mobility: Combining ORC Protocol with RRH and Using Quota Mechanism

  • Kong, Ruoshan;Feng, Jing;Gao, Ren;Zhou, Huaibei
    • Journal of Communications and Networks
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    • v.14 no.1
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    • pp.91-103
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    • 2012
  • Network mobility (NEMO) based on mobile IP version 6 has been proposed for networks that move as a whole. Route optimization is one of the most important topics in the field of NEMO. The current NEMO basic support protocol defines only the basic working mode for NEMO, and the route optimization problem is not mentioned. Some optimization schemes have been proposed in recent years, but they have limitations. A new NEMO route optimization scheme-involving a combination of the optimized route cache protocol (ORC) and reverse routing header (RRH) and the use of a quota mechanism for optimized sessions (OwR)-is proposed. This scheme focuses on balanced performance in different aspects. It combines the ORC and RRH schemes, and some improvements are made in the session selection mechanism to avoid blindness during route optimization. Simulation results for OwR show great similarity with those for ORC and RRH. Generally speaking, the OwR's performance is at least as good as that of the RRH, and besides, the OwR scheme is capable of setting up optimal routing for a certain number of sessions, so the performance can be improved and the cost of optimal routing in nested NEMO can be decreased.

International Multimodal Transport Route Development from Korea to Mongolia

  • Nyamjav, Tsenskhuu;Ha, Min-Ho
    • Journal of Navigation and Port Research
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    • v.46 no.5
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    • pp.419-426
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    • 2022
  • This study aimed to identify new routes for transporting automobiles from Korea to Mongolia by comparing them with the existing route. At present, a route from the Incheon Port through the Tianjin Port to Zamiin-Uud is commonly used to transport containerized cargo from Korea to Mongolia. This study examined five possible logistics routes from Korea to Mongolia using a time/cost-distance methodology based on real data. Through consecutive discussions with importers and freight forwarders in Mongolia, the potential routes were selected and costs, distance, and lead time were evaluated to provide additional route options for automobile logistics from Korea to Mongolia. The results indicated that each route could be ranked in terms of the total cost while the lead time for all options in the present COVID-19 period is 2 - 4 months, with no difference among the routes. In addition, although the confidence index of all routes was not impressive, route 3 was the most preferred option, followed by route 1. However, the study results cannot provide the answer to the question of "which route is more attractive for transporting automobiles from Korea to Mongolia." This limitation notwithstanding, this study provides real information on the critical factors of distance, cost, and lead time in terms of the selected transportation routes so that importers and exporters can compare the routes in terms of the priority of each factor in uncertain logistics environment.

Improving TCP Performance through Pre-detection of Route Failure in Mobile Ad Hoc Networks (Ad Hoc 망에서 경로단절 사전감지를 통한 TCP 성능향상)

  • Lee Byoung-Yeul;Lim Jae-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.11B
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    • pp.900-910
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    • 2004
  • Route failure is mainly caused by mobility of mobile host in ad hoc networks. Route failure, which may lead to sudden packet losses and delays, is losing the route from source to destination. In this situation, TCP assumes that congestion has occurred within the network and also initiates the congestion control procedures. Congestion control algorithm provides the means for the source to deal with lost packets. TCP performance in ad hoc environments will be degraded as TCP source cannot distinguish congestion from route failure. In this paper, we propose TCP-P as pre-detection approach to deal with route failure. TCP-P freezes TCP through pre-detection of route failure. Route failure information of the proposed mechanism is obtained not by routing protocol but by MAC protocol. The intermediated node, obtaining route failure information by its MAC layer, relays the information to TCP source and lets TCP source stop the congestion control algorithm. Results reveal that TCP-P responding with proactive manner outperforms other approaches in terms of communication throughput under the presence of node mobility.

Linkage of GSIS and Expert System for Route Selection (노선선정을 위한 GSIS와 전문가체계의 연계)

  • 이형석;배상호;강준묵
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.19 no.2
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    • pp.137-146
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    • 2001
  • Route selection needs the analysis function of GSIS to analyze and manipulate a lot of spatial information efficiently. Therefore, it needs the linkage of system requiring the knowledge and the experience of experts as a method that can estimate each quantitative route for an efficient route selection. In this study, the route selection model through construction and analysis procedure of position information using GSIS were presented, and route selection system linked with expert system was developed. This system is easy to be used and managed for presenting route alignment according to conditions as a graphic user interface environmental window system by applying three tiers based object-oriented method. Using GSIS, the various information required for route selections in database was constructed, the characteristics of subject area by executing three-dimensional terrain analysis was grasped effectively, and the control point through buffering, overlay and location operation was extracted. Three alternative routes between a beginning point and an end point inputted by route selection system were selected. Therefore, the applications of the route selection system are presented by applying this system to the real study area.

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Optimal Ship Route Planning in Coastal Sea Considering Safety and Efficiency (안전과 효율을 고려한 연안 내 선박의 최적 항로 계획)

  • Lee, Won-Hee;Choi, Gwang-Hyeok;Ham, Seung-Ho;Kim, Tae-wan
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2019.05a
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    • pp.38-39
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    • 2019
  • Optimal route planning is the route planning to minimize voyage time or fuel consumption in a given ocean environment. Unlike the previous studies on weather routing, this study proposes an optimization method for the route planning to avoid the grounding risk in the coast. The route way-points were searched using Dijkstra algorithm, and then the optimization was performed to minimize fuel consumption by setting the optimization design parameter to the engine rpm. To set the engine rpm, a method to use the fixed rpm from the departure point to the destination point, and a method to use the rpm for each section by dividing the route were used. The ocean environmental factors considered for route planning were wind, wave, and current, and the depth information was utilized to compute grounding risk. The proposed method was applied to the ship passing between Mokpo and Jeju, and then it was confirmed that fuel consumption was reduced by comparing the optimum route and the past navigated route.

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Applying the Analytic Hierarchy Process to Select the Optimal Route for Hazardous Material Transport (AHP 기법을 활용한 위험물 수송의 최적경로산정)

  • Son, Eu-Gene;Bae, Sang-Hoon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.13 no.4
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    • pp.67-77
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    • 2010
  • Growth of oil and chemical industries has been remarkable during recent years. Hazardous materials (Hazmat) make frequent use in the wide range of industries. It increases the frequency of Hazmat transport and it leads to increase the number of accidents. Optimal Hazmat routes can reduce damage. Thus, the objective of this study is to minimize the areas impacted by Hazmat accidents by adopting experts' opinion in planning the route. We calculated weights using AHP (Analytic Hierarchy Process) and deduced the best route by applying this weights. Results showed that in the case of shortest route versus weighted route, the percentage of population damage has been decreased by 33.4% in the comparison between shortest route and optimally weighted route. And the percentage of environmental damage also has been decreased by 21.8%. Social damage has been decreased by 1521.7%. In the case of none weighted route versus weighted route, the percentage of population damage has been decreased by 2.6% when we adopted weighted route. Consequently, the recommended route with weighted risk assessment avoids densely populated area comparing with none weighted route. Further research needs to be carried out in order to figure out the specific cost-effectiveness analysis applying the equal cost unit for each factor.