• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.93-102
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• 2005

Excessive traffic of P2P applications in the limited communication environment is considered as a network bandwidth problem. Moreover, Though P2P systems search a resource in the phase of search using weakly connected systems(peers' connection to P2P overlay network is very weakly connected), it is not guaranteed to download the very peer's resource in the phase of download. In previous P2P search algorithm (1), we had adopted the heuristic peer selection method based on Random Walks to resolve this problems. In this paper, we suggested an adaptive P2P search algorithm based on the previous algorithm(1) to reform the node distribution rate which is affected in unit peer ability. Also, we have adapted the discriminative replication method based on a query ratio to reduce traffic amount additionally. In the performance estimation result of this suggested system, our system works on a appropriate point of compromise in due consideration of the direction of searching and distribution of traffic occurrence.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.659-672
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• 2004

A Mobile Ad hoc Network (MANET) is a group of independent mobile computing nodes that consist of a multi-hop wireless network without a central administration or any infrastructure. Every node that wants to join a MANET must obtain an address for communication. Having a centralized DHCP server that provides addresses to nodes, we can easily and automatically obtain addresses. However, a MANET lacks any fixed infrastructure such as a DHCP server. We therefore propose a distributed address autoconfiguration approach for a MANET using a reserved address and optimistic Duplicated Address Detection (DAD). The reserved address helps to reduce the allocation latency, and the optimistic DAD guarantees the uniqueness of addresses and lessens communication overhead. We then suggest methods of handling network partition and network merging situations, and go on to evaluate our approach through simulations. The simulation result shows that our scheme guarantees the uniqueness of allocated address and considerably improves allocation latency and communication overheads.

• Journal of Digital Contents Society
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• v.12 no.1
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• pp.133-139
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• 2011

Structured P2P (peer-to-peer) networks have received much attention in research communities and the industry. The data stored in structured P2P networks can be located in a log-scale time without using central severs. The link-structure of structured P2P networks should be maintained for keeping log-scale search performance of it. When nodes join or leave structured P2P networks frequently, some links become unavailable and search performance is degraded by these links. To sustain search performance of structured P2P networks, periodic link recovery scheme is generally used. However, when the link recovery period is short or long compared with node join and leave rates, it is possible that sufficient number of links are not restored or excessive messages are used after the link-structure is restored. We propose the adaptive link recovery determination algorithm to maintain the link-structure of structured P2P networks when the rates of node joining and leaving are changed dynamically. The simulation results show that the proposed algorithm can maintain similar QoS under various node leaving rates.

• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.99-107
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• 2010

SNMP(Simple Network Management Protocol) is most commonly used as a standard protocol for effective network management by supporting the increasing size of the network and the variety of network elements such as router, switch, server and so on. However, SNMP has performance drawbacks of network overhead, processing latency, and the inefficiency in data retrieval. In this paper, we propose two schemes to improve the performance of SNMP; 1) the first scheme to reduce the amount of redundant OID information within a SNMP-GetBulk response message, 2) the second scheme of newly proposed SNMP-GetUpdate message combined with the cache in MNS. Through the analysis with real experiments, we show that our first scheme reduces the network overhead and the second scheme improves the processing latency and the retrieval of SNMP MB tables. And, therefore the scalability of network management can be improved.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.3
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• pp.107-117
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• 2009

Network administrator recognizes the abnormal phenomenon in the managed network by using the alert messages generated in the security devices including the intrusion detection system, intrusion prevention system, firewall, and etc. And then the series of task, which searches for the traffic related to the alert message and analyzes the traffic data, are required to determine where the abnormal phenomenon is the real network security threat or not. There are many alert messages to have to inspect in order to determine the network security situation. Also the much times are needed so that the network administrator can analyze the security condition using existing methods. Therefore, in this paper, we proposed an efficient method for analyzing network security situation using visualization. The proposed method monitors anomalies occurred in the entire IP address's space and displays the detail information of a security event. In addition, it represents the physical locations of the attackers or victims by linking GIS information and IP address. Therefore, it is helpful for network administrator to rapidly analyze the security status of managed network.

• Journal of Korea Spatial Information System Society
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• v.9 no.2
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• pp.67-79
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• 2007

Recently, to support LBS(location-based services) and telematics applications efficiently, there have been many researches which consider the spatial network instead of Euclidean space. However, existing range query and k-nearest neighbor query algorithms show a linear decrease in performance as the value of radius and k is increased. In this paper, to increase the performance of query processing algorithm, we propose materialization-based range and k-nearest neighbor algorithms. In addition, we make the performance comparison to show the proposed algorithm achieves better retrieval performance than the existing algorithm.

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

In this paper, we propose a secure communication framework for interaction and information sharing between a server and agents in DS-NVSA(Detection System of Network Vulnerability Scan Attacks) proposed in〔1〕. For the scalability and interoperability with other detection systems, we design the proposed IDMEF and IAP that have been drafted by IDWG. We adapt IDMEF and IAP to the proposed framework and provide SKTLS(Symmetric Key based Transport Layer Security Protocol) for the network environment that cannot afford to support public-key infrastructure. Our framework provides the reusability of heterogeneous intrusion detection systems and enables the scope of intrusion detection to be extended. Also it can be used as a framework for ESM(Enterprise Security Management) system.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.165-169
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• 2006

문자메시지 네트워크는 웹페이지 검색네트워크와는 위상적으로 많이 다르기 때문에 상이한 특성을 가지고 있음을 보였다. 네트워크가 성장함에 따라 강력한 허브를 구성하는 네트워크는 소수의 노드에 연결이 집중되는 특성을 가질 수 있다. 문자메시지 네트워크는 시간이 흐름에 따라서 네트워크의 밀도가 높아지는 속도가 높다는 특징을 가지고 있다. 두 개의 크기가 다른 문자메시지 네트워크에 대한 실험을 통하여 적어도 작은 집단 내의 메시지네트워크는 크기가 증가함에 따라서 허브의 집중도가 power law분포가 아닌 선형적인 특징을 가지고 있음을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.232-234
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• 2005

본 논문은 세포 내에 존재하는 방대한 단백질들 사이의 상호작용 관계 네트워크에서 생물학적인 의미 연관성을 가지는 부분 네트워크를 콤포지트로 추상화할 수 있는 방법을 제안한다. 이 추상화를 위해 네트워크에서 구조적으로 완전한 부분 네트워크, 개념적으로 인접한 부분 네트워크 그리고 두 조건을 모두 만족하는 부분네트워크를 탐색한다. 따라서, 사용자는 방대한 네트워크을 개념적인 관점에서 분석할 수 있으며, 특정한 의미을 가지는 부분 네트워크를 쉽게 검색할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.436-438
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• 2012

미래인터넷에 대한 연구가 시작되면서 새로운 네트워크 구조 및 프로토콜에 대한 실험을 용이하게 할 수 있는 소프트웨어 라우터에 대한 관심이 높아지고 있다. 고성능 소프트웨어 라우터를 구현하는 데에 있어서 해결하여야 하는 한가지 문제는 고속의 IP 주소 검색 기능의 구현이다. 최근에 고성능 IP 주소 검색 기능을 GPU의 병렬성을 이용하여 해결하려는 시도가 행해지고 있다. 본 논문에서는 GPU에 적합한 구조를 지닌 고성능의 IP 주소 검색 방법을 제안한다. GFLE라고 명명한 이 방법은 해시 테이블 기반 하에서 GPU에서 캐시 히트를 높일 수 있는 구조를 추가한 것이다. 제안한 방법은 실제 백본 라우터의 라우팅 테이블을 사용한 실험을 통하여 약 180 Mpps의 IP 주소 검색 성능을 나타내며, 기존에 발표된 방법에 비하여 프리픽스 갱신이 용이하다는 장점을 지니고 있다.