• Annual Conference of KIPS
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• 2009.04a
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• pp.737-740
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• 2009

운영체제 원격 자동설치시스템은 특히 다수의 호스트 컴퓨터로 이루어진 네트워크 환경에서 적용되어 운영체제 설치 및 업그레이드 시 유용하게 쓰이고 있다. 그러나 관리자의 설치시작 확인과정 없이 자동으로 진행되어 안정성을 보장받을 수 없고 하드웨어의 문제나 관리자의 소홀로 인한 운영체제의 반복설치 문제점이 있어 실 서비스 환경에 적용하기 어렵다. 본 논문에서는 기존의 문제점을 해결하기 위해 DHCP 프로토콜 변경을 통한 운영체제 원격 자동설치 제어방법 및 시스템을 제안하고자 한다. 호스트정보를 자동추가하고 관리자의 판단이 이루어지도록 설치대기모드 전환단계를 거쳐 실 서비스 환경에 적용할 수 있는 안정성을 확보한다.

• Annual Conference of KIPS
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• 2007.05a
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• pp.1171-1174
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• 2007

NAT는 IP주소 부족의 단기적인 해결방법으로 홈네트워크에서 널리 사용되고 있다. ISP는 트래픽 과금 등에 사용하기 위하여 NAT를 사용하는 IP 주소와 NAT에 연결된 호스트 수를 탐지하려고 한다. NAT 탐지 방법으로는 IP 패킷 헤더의 TTL 필드를 이용하는 것과 ID 필드를 이용하는 것이 있다. 본 논문에서는 NAT(Network Address Translator) 탐지를 위해 제안되어 널리 사용되는 ID 필드를 이용한 방법을 실험적으로 분석한다. 실험결과 서브넷의 계층이나 운영체제의 다양성으로 인하여 완벽하게 NAT 이용 호스트를 탐지하기 어렵다는 것을 검증하였다.

• Review of KIISC
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• v.18 no.3
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• pp.101-108
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• 2008

어떤 조직이나 개인을 상대로 한 인터넷 자원에 대한 분산 서비스 거부 공격이 통상적인 위험이 되고 있다. 이런 공격은 봇넷이라는 수많은 감염되거나 침해된 좀비 머신을 통하여 이루어지고 있다. 우리나라에서는 홈네트워크의 구축으로 광대역 액세스를 가진 개인사용자의 호스트 컴퓨터가 주 공격대상이 될 수 있다. 특히 개인 사용자들은 인터넷 보안에 대한 낮은 인식과 제한된 방어 자원으로 인하여 공격자의 대표적인 타깃이 되고 있다. IRC(Internet Relay Chat) 네트워크를 이용하여 감염된 인터넷 호스트를 제어하고 관리하는 공격들이 증가하고 있어, 이에 대한 대책이 절실히 요구되고 있는 실정이다. 따라서 본 논문에서는 인터넷 호스트들을 감염시키고 원격에서 제어하는 악성 봇/봇넷의 기술 개요에 대하여 기술하고 분석하고자 한다. 또한 최근 증가하고 있는 P2P 봇넷에 대하여도 알아보고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.175-181
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• 2006

AMobile-supported spatial database systems have been introduced with development of mobile computing technology, they offer an advantage that we can access the data wherever we are. However, the studies on database system in traditional distributed environments must be reconsidered again, because of characteristics of mobile database system such as mobility and instability of wireless network. A new transaction model should be required for considering the characteristics, since especially a mobile computing environment is location-dependent, compared with the location transparency in a distributed computing environment. In other aspect, normally mobile host may be moving not in all space, but in some limited path. That is, a host is moving along the roads or the geographical features adjacent to the roads. The transaction processing should be considered not on the spatial coordinate but on the geographical features. In this paper, the feature based transaction processing model is proposed to process location-dependent transaction efficiently.

• Journal of Korea Multimedia Society
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• v.3 no.3
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• pp.320-332
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• 2000

Web consists of the grand virtual system which is made of all connected computers network. We can solve the huge problem which requires high quality in cost performance and powerful computing power to use a numerous idle state system on internet as process it parallel. However, we have to consider heterogeneous computing resources, accessibility, and reliability to carry out parallel system on global environment, not network but whole Internet. In this paper, We the WebImg system which has the power of web computing, and show the flexible task allocation strategy in heterogeneous hosts. Also, we evaluate its performance, moreover the proposed task allocation strategy supplies fault tolerance by controlling host situation at any time.

• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.406-416
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• 1995

This paper is concerned with a routing protocol for cost-effective communications between mobile hosts on computer networks in which mobile hosts can move freely their physical positions. The proposed routing protocol consists of two protocols : one is called location registration protocol performing registration of the location information as the mobile host does move; the other one is called message transfer protocol which actually delivers a message to the destination mobile host. The detailed protocol's operational behavior and major characteristics are presented. And it is shown that our protocols are superior to previous ones, in terms of the communication cost(i.e, number of messages) required for routing a message, and are functionally improved ones.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.10
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• pp.1217-1224
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• 1999

이동 호스트들의 위치 정보를 관리하는 것은 이동 컴퓨터 시스템에서 중요한 문제이다. 이동 호스트가 이동할 때 위치 수정과 위치 탐색간에는 상반관계가 존재한다. 본 논문에서는 위치 서버를 이용한 간단한 quorum 기반 분산 동적 위치 관리 방법을 제안한다. 이 방법에서는 이동 호스트들의 위치 정보가 모든 위치 레지스터가 아닌 위치 레지스터들의 부분집합에서 효율적으로 관리되기 때문에 위치 수정 비용과 위치 탐색 비용이 감소된다. 그리고 위치 레지스터들의 부분집합은 동적으로 변하고, 각 위치 서버의 부하는 이동 호스트에 대한 질의율을 고려하므로 균등해진다. 제안된 알고리즘의 성능은 위치 수정비용과 위치 탐색비용의 전체비용으로 평가되었고, Prakash의 알고리즘과 비교되었다.Abstract Managing location information of mobile hosts is an important issue in mobile computing systems. There is a trade-off between location update and search, when a mobile host moves. This paper proposes a simple quorum-based distributed dynamic location management method using location registers. The cost of location updates and searches is reduced by our method because the location information of mobile hosts is managed efficiently in a subset of location registers instead of in all location registers. In our method, the subset of location registers is dynamically changed, and the load of each location register is balanced by considering query rate for mobile hosts. The performance of proposed algorithm is evaluated in terms of the total cost of a location update and a location search, and is compared with Prakash's algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1490-1494
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• 2006

Most network equipment is an embedded system designed to execute specific function. An embedded system is an electronic control system mixing hardware and software to execute only fixed function for the purpose of system, not confuter, performing diverse function for a wide use. Early embedded system executed only simple function, combining specific function with optimization, a micro size, and low power, but it has developed to meet complex and diverse system. The purpose of this study is to realize DHCP server based on embedded system. To achieve this, embedded Linux was ported in ez Bord-M01 mounted with Intel Strong ARM SA1110 processor, and ethernet-based network was constructed for network function. In this way, this study suggests embedded DHCP server where Window and Linux client hosts are dynamically configurated as network information by dynamically assigning network information in embedded board.

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.163-169
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• 1999

Mobile-IP has been designed to have mobile computer users move from place to place without changing their IP addresses. Mobile-IP introduces the following entities to support mobility: Home Agent. Foreign Agent, etc., and it uses the techniques such as Agent Discovery, Registration. and Tunnelling. Mobile-IP route optimization provides a mechanism by which correspondent nodes are enable to know the mobile host's care-of address to alleviate the triangle routing problem. As a further performance improvement, to alleviate the overhead resulted from the frequent local mobility within a site hierarchical foreign agents are presented, and as a foreign agent which is willing to participate in communication maintain a buffering mechanism not to loss packets for mobile host, smooth handoffs is presented. In this paper, the problems to be thought to support host's mobility and the existing method to support it is discussed.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.3
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• pp.22-30
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• 2001

This paper investigated future telemedicine as implementation of the telemonitoring system using LAN environment. For telemonitoring system rapidly implementation used the PC compatible embedded computing system in the ROMDOS and application program used the WATTCP that free TCP/IP Stack. Host computer program - programed by Visual C++ - had saved ECG signal and Patient Data coming inside Embedded PC and displayed. Embedded PC acquired ECG signal and transmitted a Packet to Host Computer. Host Computer remote access Embedded PC. This structure is the same Client/Sever Model. This system will be basic telemedicine model. There are problems of realtime telemonitoring because of network delay and data packet. Because of these problems, telemedicine systems will be required faster network speed and method of bio-signal transmission.