• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3701-3727
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• 2016

Recently Service Function Chaining (SFC) is promising to innovate the network service mode in modern networks. However, a feasible implementation of SFC is still difficult due to the need to achieve functional equivalence with traditional modes without sacrificing performance or increasing network complexity. In this paper, we present a configurable network service chaining (CNSC) mechanism to provide services for network traffics in a flexible and optimal way. Firstly, we formulate the problem of network service chaining and design an effective service chain construction framework based on integrating software-defined networking (SDN) with network functions virtualization (NFV). Then, we model the service path computation problem as an integer liner optimization problem and propose an algorithm named SPCM to cooperatively combine service function instances with a network utility maximum policy. In the procedure of SPCM, we achieve the service node mapping by defining a service capacity matrix for substrate nodes, and work out the optimal link mapping policies with segment routing. Finally, the simulation results indicate that the average request acceptance ratio and resources utilization ratio can reach above 85% and 75% by our SPCM algorithm, respectively. Upon the prototype system, it is demonstrated that CNSC outperforms other approaches and can provide flexible and scalable network services.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.3
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• pp.75-85
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• 2016

MANET is a network composed only mobile network having limited resources and has dynamic topology characteristics. Therefore, every mobile node acts as a route and delivers data by using multi-hop method. In particular, group communication such as multicast is desperately needed because of characteristics such as battery life of limited wireless bandwidth and mobile nodes. However, the multicast technique can have different efficient of data transmission according to configuring method of a virtual topology by the movement of the nodes and the performance of a multicast can be significantly degraded. In this paper, the region based security multicast technique is proposed in order to increase the efficiency of data transmission by maintaining an optimal path and enhance the security features in data transmission. The group management node that manages the state information of the member nodes after the whole network is separated to area for efficient management of multicast member nodes is used. Member node encrypts using member key for secure data transmission and the security features are strengthened by sending the data after encrypted using group key in group management node. The superiority of the proposed technique in this paper was confirmed through experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1048-1058
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• 1999

This paper compares some architectures to achieve the optimized WDM architecture for all optical transport network, the comparison is presented in terms of the number of required wavelength and LT. These architecture types are PPWDM, SHWDM, DHWDM and fully optical WDM. Topology is a static ring network where the routing pattern is fixed and traffic pattern has uniform demand. This paper also proposes an algorithm for the wavelength assignment for a folly optical WDM ring network which has full mesh traffic pattern. The algorithm is based on heuristic algorithm which assigns traffic connections according to their respective shortest path. Traffic described here that is to be passed through can be routed directly within the optical layer instead of having the higher layer to handle it.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.7
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• pp.1721-1736
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• 2013

Black and gray hole attack is one kind of routing disturbing attacks and can bring great damage to the network. As a result, an efficient algorithm to detect black and gray attack is important. This paper demonstrate an adaptive approach to detecting black and gray hole attacks in ad hoc network based on a cross layer design. In network layer, we proposed a path-based method to overhear the next hop's action. This scheme does not send out extra control packets and saves the system resources of the detecting node. In MAC layer, a collision rate reporting system is established to estimate dynamic detecting threshold so as to lower the false positive rate under high network overload. We choose DSR protocol to test our algorithm and ns-2 as our simulation tool. Our experiment result verifies our theory: the average detection rate is above 90% and the false positive rate is below 10%. Moreover, the adaptive threshold strategy contributes to decrease the false positive rate.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.199-201
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• 2012

무선 멀티미디어 센서 네트워크를 활용하기 위한 응용에서는 대용량 멀티미디어 데이터 저장 및 처리 기술, 데이터 전송 기술 등과 같은 다양한 기반 기술들이 요구된다. 특히, 응용을 실제 환경에 적용하기 위해서는 대용량 데이터에 대한 데이터 보안 기술은 필수적이다. 본 논문은 여러 해킹 기술 중 하나인 스니핑 공격으로부터 원천적인 방어를 위해, 데이터 전송 경로를 위험 요소로부터 물리적으로 회피시키기 위한 다중 경로 라우팅 기법을 제안한다. 제안하는 기법은 위험 요소의 감지 반경과 움직임을 토대로 위험 요소의 인근에 위치한 센서 노드에 준비태세 단계를 설정한다. 이를 기반으로 데이터의 우선 순위를 설정하여 데이터 라우팅 과정에서 준비태세 단계와 데이터의 우선 순위를 고려하여 우선순위에 맞는 안전한 경로를 통해 위험요소 우회 다중 경로 라우팅을 수행한다. 시뮬레이션을 통해 제안하는 기법의 구현 가능성을 제시하였으며, 준비태세를 기반으로 효과적인 위험요소 우회 다중 경로 라우팅을 보였다.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.3
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• pp.120-132
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• 2008

Networks-on-Chip (NoC) is emerging as a practical development platform for future systems-on-chip products. We propose an energy-efficient static algorithm which optimizes the energy consumption of task communications in NoCs with voltage scalable links. In order to find optimal link speeds, the proposed algorithm (based on a genetic formulation) globally explores the design space of NoC-based systems, including network topology, task assignment, tile mapping, routing path allocation, task scheduling and link speed assignment. Experimental results show that the proposed design technique can reduce energy consumption by 28% on average compared with existing techniques.

• Journal of Computing Science and Engineering
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• v.5 no.4
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• pp.316-323
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• 2011

Recently, Proxy Mobile IPv6 (PMIPv6) has received much attention as a mobility management protocol in next-generation all-IP mobile networks. While the current research related to PMIPv6 mainly focuses on providing efficient handovers for unicast-based applications, there has been relatively little interest in supporting multicast services with PMIPv6. To provide support for multicast services with PMIPv6, there are two alternative approaches called Mobile Access Gateway (MAG)-based subscription and Local Mobility Anchor (LMA)-based subscription. However, MAG-based subscription causes a large overhead for multicast joining and LMA-based subscription provides non-optimal multicast routing paths. The two approaches may also cause a high packet loss rate. In this paper, we propose an efficient PMIPv6-based multicast protocol that aims to provide an optimal delivery path for multicast data and to reduce handover delay and packet loss rate. Through simulation studies, we found that the proposed protocol outperforms existing multicast solutions for PMIPv6 in terms of end-to-end delay, service disruption period, and the number of lost packets during handovers.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.499-505
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• 2004

In this paper, we studied about AGVs modeling and material handling automation simulation using a virtual AGV. The proposed virtual AGV model that operates independently each other is based on a real AGV. Continuous straight-line and workstation model using vector drawing method that could easily, rapidly work system modeling are suggested. Centralized traffic control, which could collision avoidance in intersection and should not stop AGV as possible, and algorithm for detour routing which performs when another AGV is working in pre-routed path are proposed. The traffic control and the algorithm have been proved efficience by simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3086-3097
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• 1996

Generally, the performance of the computer network may differ according to various parameters like routing, bandwidth and timers. Since the network system requirements may widely very according to specific application, computer network must be tailored at tailored at the design starge by selection of appropriate protocols and assignment of degfault parameter. However, since the condition under which a network actually operates may change from that considered at the design stage, control and managment action are required to adjust the network parameter so that the perforance of network is satisfied.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.6
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• pp.129-135
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• 2010

This paper suggests a multipath establishing scheme for ad hoc networks. Data paths are established by on-demand manner. Multipath are made as a sequence of route control message exchange at route setup process. Multipath can be used as a backup path or load balancing for data exchange. Proposed scheme uses a one-hop pre-search scheme for establishing multipath between source and destination. When a node selects a next node for route reply, the node finds optimal route by exchanging route information with neighbor nodes. Simulation results show that the proposed multipath scheme has better split characteristics among multipath and higher route survivability at the environment where nodes are moving.