• Spatial Information Research
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• 제21권2호
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• pp.1-9
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• 2013

최근 이동통신 기술의 발전으로 실내에서의 위치 획득 기술이 용이해지면서 실내 내비게이션 시스템에 대한 연구가 각광을 받고 있다. 최적화된 실내 내비게이션은 크고 복잡한 실내에서의 활동을 위해 빠른 경로를 제공한다. 그러나 기존의 실내 내비게이션 알고리즘 연구들에서는 공간 토폴로지 또는 실내 네트워크에 기반하여 대략적인 경로를 도출한다. 본 논문에서는 공간 토폴로지 분석과 실내 내트워크를 통합 분석하여 실내 경로를 계산하는 알고리즘을 제안한다. 제안 알고리즘은 전문적인 실내지도가 아닌 간소화된 실내 지도 데이터를 활용하여 실내 네트워크와 공간 토폴로지의 혼합 분석을 통해 실내 경로의 길이를 줄일 수 있다. 성능평가를 통해 FT-Indoornavi 알고리즘이 기존의 엘라스틱 알고리즘과 iNav 알고리즘보다 더 빨리 실내 경로를 계산할 수 있음을 보여준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2473-2489
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• 2022

Urban development has brought about the increasing saturation of urban traffic demand, and traffic congestion has become the primary problem in transportation. Roads are in a state of waiting in line or even congestion, which seriously affects people's enthusiasm and efficiency of travel. This paper mainly studies the discrete domain path planning method based on the flow data. Taking the traffic flow data based on the highway network structure as the research object, this paper uses the deep learning theory technology to complete the path weight determination process, optimizes the path planning algorithm, realizes the vehicle path planning application for the expressway, and carries on the deployment operation in the highway company. The path topology is constructed to transform the actual road information into abstract space that the machine can understand. An appropriate data structure is used for storage, and a path topology based on the modeling background of expressway is constructed to realize the mutual mapping between the two. Experiments show that the proposed method can further reduce the interpolation error, and the interpolation error in the case of random missing is smaller than that in the other two missing modes. In order to improve the real-time performance of vehicle path planning, the association features are selected, the path weights are calculated comprehensively, and the traditional path planning algorithm structure is optimized. It is of great significance for the sustainable development of cities.

• 융합보안논문지
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• 제8권2호
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• pp.95-102
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• 2008

본 논문에서는 simple node 토폴로지의 망 정보를 효율적으로 요약함으로써 망에서의 호 성공률, 액세스 타임을 향상시켜 망의 전체적인 QoS를 향상시키기 위한 토폴로지 요약 기법을 제안하였다. 제안된 기법에서는 대역폭과 지연 파라미터를 중심으로 라인 세그먼트를 이용하여 경계노드 사이의 다중 경로 정보를 요약함으로써 토폴로지 요약 정보를 줄이고 다중링크 요약에 유연성을 부여하여 망의 성능을 향상시킬 수 있었다. 제안된 기법의 성능을 평가하기 위해 기존의 simple node 토폴로지 요약 기법과 호 성공률, 접근시간에 대하여 컴퓨터 시뮬레이션을 통해 비교 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권5호
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• pp.1303-1315
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• 2012

In the draft of the IEEE 802.11s standard, a tree topology is established by the proactive tree-building mode of the Hybrid Wireless Mesh Protocol (HWMP). It is used for cases in which the root station (e.g., gateway) is an end point of the majority of the data connections. In the tree topology, the root or central stations (e.g., parent stations) are connected to the other stations (e.g., leaves) that are one level lower than the central station. Such mesh stations are likely to suffer heavily from contention in bottleneck links when the network has a high traffic load. Moreover, the dependence of the network on such stations is a point of vulnerability. A failure of the central station (e.g., a crash or simply going into sleep mode to save energy) can cripple the whole network in the tree topology. This causes performance degradation for end-to-end transmissions. In a connected mesh topology where the stations having two or more radio links between them are connected in such a way that if a failure subsists in any of the links, the other link could provide the redundancy to the network. We propose a scheme to utilize this characteristic by organizing the network into concentric tiers around the root mesh station. The tier structure facilitates path recovery and congestion control. The resulting mode is referred to as Tier-based Proactive Path Selection Mode (TPPSM). The performance of TPPSM is compared with the proactive tree mode of HWMP. Simulation results show that TPPSM has better performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.1911-1930
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• 2017

Overlay routing has emerged as a promising approach to improve reliability and efficiency of the Internet. The key to overlay routing is the placement and maintenance of the overlay infrastructure, especially, the selection and placement of key relay nodes. Spurred by the observation that a few relay nodes with high betweenness centrality can provide more optimal routes for a large number of node pairs, we propose a resilient routing overlay network construction method by introducing Super-Relay nodes. In detail, we present the K-Minimum Spanning Tree with Super-Relay nodes algorithm (SR-KMST), in which we focus on the selection and connection of Super-Relay nodes to optimize the routing quality in a resilient and scalable manner. For the simultaneous path failures between the default physical path and the overlay backup path, we also address the selection of recovery path. The objective is to select a proper one-hop recovery path with minimum cost in path probing and measurement. Simulations based on a real ISP network and a synthetic Internet topology show that our approach can provide high-quality overlay routing service, while achieving good robustness.

• Kyungpook Mathematical Journal
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• 제46권3호
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• pp.445-448
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• 2006

Let N be a normal subgroup of a path-connected topological group (G, $t$). In this paper, the authors consider the existence of path-connectedness in refined topologies in order to address the property of maximal path-connectedness in topological groups. In particular, refinements on $t$ and refinements on the quotient topology on G/N are studied. The preservation of path-connectedness in extending topologies and translation topologies is also considered.

• 대한교통학회지
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• 제19권6호
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• pp.183-194
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• 2001

중앙집중형 도로교통정보시스템은 실시간 교통정보를 수집하고, 사용자의 요청을 받아 경로탐색, 위치정보, 목적지탐색 등의 정보를 전달해주는 시스템이다. 이러한 시스템에서 서버는 매우 많은 클라이언트로부터 경로탐색 요청을 받게 되며, 이 요청을 서버에서 효율적으로 처리해야 하는 다중경로탐색 알고리즘이 필요하다. 본 연구에서는 다중경로탐색을 수행하기 위하여, 주기적으로 연산된 이웃노드의 최단경로탐색 결과를 이용하여 클라이언트의 경로탐색 수행시간을 감소시키는 휴리스틱(Heuristic) 알고리즘을 제시한다. 본 연구에서 제시하는 이웃노드 최단경로탐색 결과를 이용한 다중경로탐색 알고리즘은 많은 경우에 최단과 동일한 결과를 나타내며, 최단이 아닌 경우에도 최단경로 값과 오차가 크지 않으면서도 연산시간을 많이 줄일 수 있는 알고리즘이고, 도로교통과 같은 토폴로지(Topology) 형태에 효과적으로 적용되고, 계층을 이루는 형태의 모델에서도 효율적인 결과를 나타낸다. 이웃노드 최단경로탐색 결과를 이용한 다중경로탐색 알고리즘의 경로탐색시간은 다른 꼬리표설정 알고리즘과 꼬리표개선 알고리즘보다 50배 이상 빨랐으며, 경로탐색 결과가 최단이 아닌 경우 0.1%이하의 거리오차가 발생했다.

• 한국정보처리학회논문지
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• 제7권6호
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• pp.1778-1784
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• 2000

We consider the weighted shortest path updating problem, that is, the problem to reconstruct the weighted shortest paths in response to topology change of the network. This appear proposes a distributed algorithms that reconstructs the weighted shortest paths after several processors and links are added and deleted. its message complexity and ideal-time complexity are O(p$^2$+q+n') and O(p$^2$+q+n') respectively, where n' is the number of processors in the network after the topology change, q is the number of added links, and p is the total number of processors in he biconnected components (of the network before the topology change) including the deleted links or added links.

• 융합보안논문지
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• 제23권1호
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• pp.3-8
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• 2023

다중 도메인 광 전송망은 기본적으로 상호 운용되지 않으며 전체 망차원의 통합 오케스트레이션 메커니즘과 경로 제공 메커니즘이 필요하다. 더불어 망의 생존성 보장은 중요한 쟁점 중의 하나이다. MPLS-TP(Multi-Protocol Label Switching-Transport Profile)에서는 다양한 보호·복구 방안을 표준으로 정의하고 있으나 보호·복구 경로를 계산·선정하는 방안에 대해서는 언급하고 있지 않다. 따라서 광회선패킷 통합망 차원에서 보호·복구 충돌을 최소화하여 통합망 전 영역에 걸쳐 신속한 보호·복구가 가능한 경로를 계산·설정하는 알고리즘이 필요하다. 본 논문에서는 다중링-메시 토폴로지 형태로 구성된 T-SDN 망에서 신속한 보호·복구가 가능한 경로를 계산·설정하는 알고리즘을 제안하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권11호
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• pp.3163-3181
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• 2023

Eavesdropping attacks have seriously threatened network security. Attackers could eavesdrop on target nodes and link to steal confidential data. In the traditional network architecture, the static routing path and the important nodes determined by the nature of network topology provide a great convenience for eavesdropping attacks. To resist monitoring attacks, this paper proposes a random routing mutation defense method based on dynamic path weight (DPW-RRM). It utilizes network centrality indicators to determine important nodes in the network topology and reduces the probability of important nodes in path selection, thereby distributing traffic to multiple communication paths, achieving the purpose of increasing the difficulty and cost of eavesdropping attacks. In addition, it dynamically adjusts the weight of the routing path through network state constraints to avoid link congestion and improve the availability of routing mutation. Experimental data shows that DPW-RRM could not only guarantee the normal algorithmic overhead, communication delay, and CPU load of the network, but also effectively resist eavesdropping attacks.