• KIPS Transactions on Computer and Communication Systems
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• v.5 no.7
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• pp.153-158
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• 2016

Delay Tolerant Network (DTN) is a network that employed method of store-carry-forward in intermittently connected networks. In DTNs, routing and buffer management scheme are important to improve successful message delivery. This paper proposes an improve spray and wait routing protocol based on delivery probability to a destination. Also, a buffer management scheme is proposed to drop the queued messages according to the number of copies (L value). Simulation results show that the proposed method provides a better delivery ratio and lower communication overhead when compared to existing schemes such as Epidemic, PRoPHET and spray and wait.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.4
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• pp.97-106
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• 2014

In this paper, we propose a design method to extend certain cognitive radio (CR) MAC protocols originally proposed only for the one hop applications in distributed CR networks to MANET routing protocols. Among several CR MAC protocols, the opportunistic MAC (called O-MAC) and the opportunistic period MAC (called OP-MAC) are considered, and AODV as MANET routing protocol is used. We implement the protocols using OPNET network simulator, and compare the performances in both MAC and AODV routing environments. With the experiments, we analyze the relationship between MAC and routing performances of the CR protocols.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.5
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• pp.191-198
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• 2013

It is required to transmit data through shorter path between sensor and base node for real time intrusion detection in wireless sensor networks (WSN) with a mobile base node. Because minimum Wiener index spanning tree (MWST) based routing approach guarantees lower average hop count than that of minimum spanning tree (MST) based routing method in WSN, it is known that MWST based routing is appropriate for real time intrusion detection. However, the minimum Wiener index spanning tree problem which aims to find a spanning tree which has the minimum Wiener index from a given weighted graph was proved to be a NP-hard. And owing to its high dependency on certain nodes, minimum Wiener index tree based routing method has a shorter network lifetime than that of minimum spanning tree based routing method. In this paper, we propose a multi-objective ant colony optimization algorithm to tackle these problems, so that it can be used to detect intrusion in real time in wireless sensor networks with a mobile base node. And we compare the results of our proposed method with MST based routing and MWST based routing in respect to average hop count, network energy consumption and network lifetime by simulation.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.71-76
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• 2003

Internet traffic is getting tremendously heavier due to the exponential growth of the Internet users, the spread of the E-commerce and the network games. High-speed routers for fast packet forwarding are commercially available to satisfy the growing bandwidth. A high-speed router, which has the decentralized multiprocessing architecture for IP and routing functions, consists of host processors, line interfaces and switch fabrics. In this paper, we propose a software architecture tuned for high-speed non-forwarding packet manipulation. IPCMP (Inter-Processor Communication Message Protocol), which is a mechanism for IPC (Inter-Processor Communication), is also proposed and implemented as well. Proposed IPC mechanism results in faster packet-processing rate by 10% as compared to the conventional IPC mechanism using UDP/IP.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.11-22
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• 2009

For a wireless ad-hoc network, event routing algorithm of the publish/subscribe system is especially important for the performance of the system because of the dynamic characteristic and constraint network of its own. In this paper, we propose a new hybrid event routing algorithm. TopSim for efficient publish/subscribe system on the wireless ad-hoc network by extending the ShopParent algorithm by considering not only network overheads to choose a Parent of the publish/subscribe tree, but also topic similarity which is closeness of subscriptions. Our evaluation shows our proposed TopSim performs better for the case where a new joining node subscribed to the multiple topics and there is a node among Parent candidate nodes who subscribe to the ones in the list of multiple topics (related topics).

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.139-147
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• 2009

BLAST (Basic Local Alignment Search Tool) is a best well-known tool in a bioinformatics area. BLAST quickly compares input sequences with annotated huge sequence databases and predicts their functions. It helps biologists to make it easy to annotate newly found sequences with reduced experimental time, scope, and cost. However, as the amount of sequences is increasing remarkably with the advance of sequencing machines, performance of BLAST has been a critical issue and tried to solve it with several alternatives. In this paper, we propose a new PC-Based Cluster system (E-Cluster), a new physical data design methodology (logical partitioning technique) and a query routing technique (intra-query routing). To verify our system, we measure response time, speedup, and efficiency for various sizes of sequences in NR (Non-Redundancy) database. Experimental result shows that proposed system has better speedup and efficiency (maximum 600%) than those o( conventional approaches such as SMF machines, clusters, and grids.

• Journal of Digital Contents Society
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• v.19 no.3
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• pp.505-512
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• 2018

Internet demand has increased rapidly, and Internet Protocol Version 4, the main Internet protocol, can not cope with various types of network demand in the future. Therefore, it is urgent to spread IPv6-based stable network to solve the shortage of Internet address resources. Due to the proliferation of IoT and the increase in mobile devices, efficient and optimal IPv6 routing design is indispensable. In this paper, we have studied about characteristics of IPv6, address system of IPv6, structure analysis and efficient routing technology among IPv6 terminals. Furthermore, experimental results on routing packet analysis and convergence time are presented in network - based IPv6 routing implementation environment. In addition, we show the results of the experiment analysis by dividing the implementation of IPv6 routing, operation test, and fail over performance into three kinds of routing protocol methods. As a result, this study can be applied to the introduction of IPv6 system, test bed environment construction, and network design.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.4
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• pp.155-162
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• 2013

Routing protocol in ad hoc mobile networking has been an active research area in recent years. However, the environments of ad hoc network tend to have vulnerable points from attacks, because ad hoc mobile network is a kind of wireless network without centralized authentication or fixed network infrastructure such as base stations. Also, existing routing protocols that are effective in a wired network become inapplicable in ad hoc mobile networks. To address these issues, several secure routing protocols have been proposed: SAODV and SRPTES. Even though our protocols are intensified security of networks than existing protocols, they can not deal fluidly with frequent changing of wireless environment. Moreover, demerits in energy efficiency are detected because they concentrated only safety routing. In this paper, we propose an energy efficient secure routing protocol for various ad hoc mobile environment. First of all, we provide that the nodes distribute security information to reliable nodes for secure routing. The nodes constitute tree-structured with around nodes for token escrow, this action will protect invasion of malicious node through hiding security information. Next, we propose multi-path routing based security level for protection from dropping attack of malicious node, then networks will prevent data from unexpected packet loss. As a result, this algorithm enhances packet delivery ratio in network environment which has some malicious nodes, and a life time of entire network is extended through consuming energy evenly.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.697-699
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• 2004

최근 MANET(Mobile Ad-hoc Networks)에서의 P2P 응용을 이용한 서비스 개발이 활발히 진행 중이다. 이와 함께 에드혹 환경에서의 적합한 P2P 모델에 관한 연구로 기존 P2P 모델인 Gnutella, DHT등을 에드혹에 적용한 연구 역시 활발히 이루어지고 있다. 본 논문에서는 on-demand 방식의 에드혹 라우팅 프로토콜인 AODV(Ad-hoc On-Demand Distance Vector)상에서, 대표적인 P2P 응용인 Gnutella의 동작 과정을 통해 P2P 응용이 갖는 문제점을 분석하고, P2P 응용의 검색과정에서 발생하는 오버헤드를 줄이기 위한 방안을 제안한다. 그리고 위의 연구 결과를 바탕으로 현재 IPv6 AODV상에서 MANET을 위한 응용인 DiPP(Fully Distributed Peer-to-Peer)시스템을 구현한다. DiPP 시스템은 MANET상에서의 메신저와 파일공유를 위한 기능을 위해 동작한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1283-1286
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• 2005

최근의 대용량 다중 분산 라우터 시스템은 다수의 라인 인터페이스 모듈들과 라우팅 처리 모듈, 스위칭 패브릭 모듈로 구성되어 있고, 고속의 패킷 스위칭 및 라우팅을 구현하기 위하여 일반적으로 입력 패킷을 외부로 전송하기 위한 기능과 제어 및 관리 기능을 담당하는 기능으로 분리하여 실행되고 있다. 이러한 라우터에서는 내부 모듈들의 프로세서들 사이에 정보 송수신을 위해 프로세서 간 통신(IPC : Interprocess Communication)이 이용되고 있다. 라우터의 기능 중 제어 및 관리 기능은 신속한 처리를 위하여 UDP/IP 방식의 IPC 가 사용되고 있는데, 이 UDP/IP 방식을 개선 방안을 제안하고 prototype 시스템을 구현하여 시험한 결과 라우터의 데이터 round trip 시간과 throughput 이 각각 15.1%, 4.3%의 개선되어 라우터의 성능이 향상되었다.