• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.6
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• pp.20-26
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• 2001

In this paper, we design tunnel inner section displacement measurement system which is composed of potentiometer-type displacement sensors, microcontroller-based intelligent sensing head and host computer for the management system and acquisition data. Multiple node communication bus connects the intelligent sensing heads with the host computer. For safe and re1iab1e network operation we use daisy-chain configuration, termination resistor, fail-safe biasing circuit. For tole enhancement of system utilization, we use modbus protocol. The acquisition data are transmitted to host computer and managed by database. Several data request conditions and sorting conditions are provided by management software. The utilization of designed system is confirmed by experiment.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.289-296
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• 2001

The Election protocol can be used as a building block in many practical problems such as group communication, atomic commit and replicated data management where a protocol coordinator might be useful. The problem has been widely studied in the research community since one reason for this wide interest is that many distributed protocols need an election protocol. However, despite its usefulness, to our knowledge there is no work that has been devoted to this problem in a mobile computing environment. Mobile systems are more prone to failures than conventional distributed system. Solving election in such an environment requires from a set of mobile hosts to choose a mobile host or a fixed host based on the their priority despite failures of both mobile computing and/or fixed hosts. In this paper, we describe a solution to the election problem from mobile computing systems. This solution is based on the Garcia Molina\\`s Bully algorithm.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.835-841
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• 2000

호스트와 타겟 간의 통신 부담과 타겟 자원이 제한적이라는 문제를 해결하기 위해서, 호스트 중심 원격 개발 환경(Remote Development Environment: RDE)을 구성하였다. 이 원격 개발 환경은 여러 개발 도구로 구성되어 있는데, 이들 도구가 타겟시스템에 접속하여 내장형 응용를 개발하는데 있어서 공통 기능, 공통 데이터가 존재한다. 그런데 이들을 각각 유지시키는 것은 타겟시스템에 부담을 줄 뿐만 아니라, 개발 도구를 추가/구현하는 것도 매우 어렵게 한다. 이 문제를 해결하기 위해 원격 개발 도구들의 공통 요소들을 모아 도구와 타겟시스템 사이에 중개자 역할을 하는 타겟관리자를 둔다. 타겟관리자는 미들웨어로서 호스트와 타겟 간의 통신 채널을 하나로 유지하면서 도구와 타겟 간의 통신을 중재하고, 도구들이 심볼 테이블을 공유할 수 있도록 심볼 테이블을 관리한다. 또한, 타겟에 있는 도구 전용 메모리를 관리하며, 호스트 상에서 개발한 내장형 소프트웨어를 타겟에 로딩하는 일을 처리한다. 이러한 타겟관리자를 사용하는 원격 개발 환경은 도구들에게 공통 인터페이스를 제공하여, 통신 방식 등의 하부 구조에 상관없이 서비스를 받을 수 있고, 새로운 도구를 추가하는 것도 용이하게 할 수 있다는 장점을 갖게 된다. 본 논문에서는 ETRI 에서 개발 중인 실시간 운영 체제인 Q+용 타겟관리자를 설계하고 구현한다. 또한, 타겟관리자가 동작하게 될 내장형 실시간 응용 개발 환경에 대하여 소개하고, 구현 결과를 도구들과 연계하여 보여주며, 타겟 관리자를 둔 원격 개발 환경이 타겟 관리자를 두지 않은 경우에 비해 호스트와 타겟 간의 통신 횟수가 얼마나 감소하는지 시험 결과를 통해 보여준다. 현재 타겟 관리자의 프로토타입을 개발하여 도구들과 통합 시험을 하였는데 기본 기능들이 성공적으로 수행됨을 확인하였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.111-122
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• 2002

Malicious attackers generally attempt to intrude the target systems by taking advantage of existing system vulnerabilities and executing readily available code designed to exploit blown vulnerabilities. To the network security administrators, the rat and minimal step in providing adequate network security is to identify existing system vulnerabilities and patch them as soon as possible. Network-based vulnerability analysis scanners (NVAS), although widely used by network security engineers, have shortcomings in that they depend on limited information that is available and generally do not have access to hast-specific information. Host-based vulnerability analysis scanner (HVAS) can serve as an effective complement to NVAS. However, implementations of HVAS differ from one platform to another and from one version to another. Therefore, to security engineers who often have to maintain a large number of heterogeneous network of hosts, it is impractical to develop and manage a large number of HVAS. In this paper, we propose an agent-based architecture named ISMAEL and describe its prototype implementation. Manager process provides various agent processes with descriptiom on vulnerabilities to check, and an agent process automatically generates, compiles, and executes an Java code to determine if the target system is vulnerable or not. The result is sent back to the manager process, and data exchange occurs in % format. Such architecture provides maximal portability when managing a group of heterogeneous hosts and vulnerability database needs to be kept current because the manager process need not be modified, and much of agent process remains unchanged. We have applied the prototype implementation of ISMAEL and found it to be effective.

• Convergence Security Journal
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• v.1 no.1
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• pp.57-68
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• 2001

Computer security is considered important because of the side effect generated from the expansion of computer network and rapid increase of the use of computer. Intrusion Detection System(IDS) has been an active research area to reduce the risk from intruders. In this paper, the Hybrid Intrusion Detection System(HIDS) based biometric immuntiy collects and filters audit data by misuse detection is innate immune, and anomaly detection is acquirement immune in multi-hosts. Since, collect and detect audit data from one the system in molt-hosts, it is design and implement of the intrusion detection system which has the immuntiy the detection intrusion in one host possibly can detect in multi-hosts and in the method of misuses detection subsequently.

• Journal of the Korea Computer Industry Society
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• v.2 no.11
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• pp.1383-1394
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• 2001

Through the extension of damages caused by hacking and computer virus, although security control has been emphasized, hackers' capability exceeded the security controllability. The basic security setup of server system will be free from the damages by primary and intermediate level which are the major group. It should be noted that security condition of most middle-sized and personal systems is widely open for hacker's intrusion. There is no perfect information system either software-wise or hardware-wise. It has to be recognized that our systems will be attacked easily by the hackers and computer virus. Computer users are demanded to be prepared for these types of surprise attacks. In this paper, I will propose a formation of Bastion server. This will protect risks from inside & outside intrusion which have been known till today.

• The Transactions of the Korea Information Processing Society
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• v.5 no.10
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• pp.2627-2640
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• 1998

In this paper, we analyze the performance of the virtual cell system[1] for the transmission of IP datagrams in mobile computer communications. A virtual cell consistsof a group of physical cells shose base stationsl are implemented b recote bridges and interconnected via high speed datagram packet switched networks. Host mobility is supported at the data link layer using the distributed hierachical location information of mobile hosts. Given mobility and communication ptems among physical cells, the problem of deploying virtual cells is equivalent to the optimization cost for the entire system where interclster communication is more expesive than intracluster communication[2]. Once an iptimal partitionof disjoint clusters is obtained, we deploy the virtual cell system according to the topology of the optimal partition such that each virtual cell correspods to a cluser. To analyze the performance of the virtual cell system, we adopt a BCMP open multipel class queueing network model. In addition to mobility and communication patterns, among physical cells, the topology of the virtual cell system is used to determine service transition probabilities of the queueing network model. With various system parameters, we conduct interesting sensitivity analyses to determine network design tradeoffs. The first application of the proposed model is to determine an adequate network bandwidth for base station networking such that the networks would not become an bottleneck. We also evaluate the network vlilization and system response time due to various types of messages. For instance, when the mobile hosts begin moving fast, the migration rate will be increased. This results of the performance analysis provide a good evidence in demonsratc the sysem effciency under different assumptions of mobility and communication patterns.

• Proceedings of the KAIS Fall Conference
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• 2001.05a
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• pp.362-365
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• 2001

앞으로의 컴퓨터 시스템은 호스트 집중형 매인프레임 컴퓨팅, 클라이언트/서버, 분산객체, ERP시스템 등으로 발전하는 것으로 전망된다. 메인프레임을 통한 호스트 중심의 중앙집중형 시스템이 네트워크와 PC의 발전으로 클라이언트/서버 시스템의 시대를 열었다. 분산 환경에서 사용자들은 여러 저장 장치로부터 정보를 얻을 수 있고 서로 다른 이질적인 시스템에 있는 사용자들과 함께 자료를 공유, 통신할 수 있어야 한다. 때문에 분산 애플리케이션을 작성하기 위해서는 일단 서로 다른 운영체계와 네트워크 환경 등으로 구성된 이질적이고 복잡한 환경을 전제로 삼아야 한다. 이러한 환경에서 클라이언트/서버 소프트웨어를 개발하고 이를 서로 다른 시스템과 쉽게 통합할 수 있기 위해서는 이종의 분산 환경에서 여러 종류의 옹용 프로그램을 통합할 수 있는 표준의 결합 방식이 필요하다. 분산 객체 시스템과 ERP시스템이 도입ㆍ구축되었다고 해서 기업의 경쟁력이 강화되고 이윤 극대화가 달성되고 고객만족이 이루어지는 것은 아니다. 최적의 ERP시스템을 구축하기 위해서 도입단계에서부터 체계적인 접근이 필요하다. 본 연구에서는 ERP서버의 현황과 분산객체 미들웨어를 활용한 ERP서버에 대해 기술하고 ERP시스템 도입에 대한 분석을 시도함으로써 ERP 시스템의 성공적인 도입전략에 대해 연구하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.12
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• pp.2649-2656
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• 2012

Today, many enterprises have invested heavily for the part of information security in order to protect the internal critical information assets and the business agility. However, there is a big problem that big budget and too many manpower are needed to set the internal corporate network up to the same high level of defense for all of part. On the distributed enterprise networks in this paper, a defense model for effective and rapid response on the IP spoofing attack was designed to protect the enterprise network through the exchange of information between the trust hosts when an attacker attacked any target system using other trusted host.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.557-560
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• 2005

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.