• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.275-278
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• 2002

이동성을 제공하기 위해 IETF에서는 Mobile IP 라는 프로토콜을 제안하였다. IETF에서는 주소고갈 문제를 해결하기 위해 앞으로도 계속적인 수요를 충족시킬 만큼의 충분한 주소를 제공할 수 있는 IPv6의 차세대 인터넷 프로토콜을 채택하였다. 본 논문에서는 Mobile IP에서 핸드오프가 발생할 때 패킷의 손실을 최소화하는 과정을 알아본다. 또한 Mobile IP기능을 IPv6에서 재설계함으로써 이동 노드가 접속점을 변경시킬 때 핸드오버가 발생하는데 이때, 성능 향상을 위한 바인딩 캐쉬 서버 도입과 지역등록 방안을 제안한다. 제한 사항에 대한 시뮬레이션을 하기 위해 Linux Machine을 이용한 Network Simulator(version-2)를 사용 하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2B
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• pp.118-123
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• 2007

This paper studied the transmission control protocol over IP network to enhance the performance of the GSO satellite communication networks. The focus of this study is how to reduce the long round trip time and the transmission data rates over satellite link in the bidirectional satellite network. To do it, this study applied the caching and spoofing technology. The spoofing technology is used to reduce the required time for the link connection during communication. The caching technology is to improve the transmission bandwidth efficiency in the high transmission data rate link The tests and measurements in this study was performed in the commercial GSO communication satellite network and the terrestrial Internet network. The results of this paper show that the studied protocol in this paper highly enhance the performance of the bidirectional satellite communication network compare to the using TCP/IP satellite network protocol.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.142-144
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• 2005

Distributed Denial of Service는 네트워크나 개인 호스트를 위협하는 대표적인 공격 트래픽이다. DDoS 공격은 특정한 패턴을 가지고 있지 않기 때문에 탐지가 어려울 뿐 아니라, TNF2K와 같은 간단한 tool로 공격이 가능하여 그 심각성은 실로 크다. 이러한 DDoS를 탐지하기 위한 메카니즘이나 알고리즘은 많이 개발되었다. 하지만 DDoS의 근원지를 판별하고 대응하는 것이 아닌, 단지 방어 지정에서 전체 threshold를 낮추거나 leaky bucket처럼 수용 능력 이상의 패킷을 폐기하는 방법으로 네트워크나 개인 호스트를 보호한다. 무분별하게 전체 트래픽을 줄이는 것은 네트워크의 resource를 고갈 시키지는 않지만, 정상적인 clients가 공격당하고 있는 호스트에 연결을 할 수가 없다. 이를 위해 여러 단계의 테스트를 통해 합법적인 검증 IP table을 만들고, 검증 IP table에 있는 source IP를 제외한 나머지 트래픽을 차단한다면, DDoS 공격에 대해서 대응을 하면서 정상적인 Clients의 연결을 보호 할 수 있다.

• International Journal of Safety
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• v.5 no.2
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• pp.6-11
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• 2006

The time delay in servo control on LonWorks/IP Virtual Device Network (VDN) is highly stochastic in nature. LonWorks/IP VDN induced time delay deteriorates the performance and stability of the real-time distributed control system and hinders an effective preventive and predictive maintenance. Especially in real-time distributed servo applications on the factory floor, timely response is essential for predictive and preventive maintenance. In order to guarantee the stability and performance of the system for effective preventive and predictive maintenance, LonWorks/IP VDN induced time delay needs to be predicted and compensated for. In this paper position control simulation of DC servo motor using Zero Phase Error Tracking Controller (ZPETC) as a feedforward controller, and Internal Model Controllers (IMC) based on Smith predictor with disturbance observer as a feedback controller is performed. The validity of the proposed control scheme is demonstrated by comparing the IMC based on Smith predictor with disturbance observer.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.649-653
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• 2000

Mobile IP[1]환경에서 (Mobile Node)[1]는 (Foreign Agent)[1]와 (Home Agent[1])간에 컨트롤 메시지들을 주고 받으며 이러한 컨트롤 메시지들은 인증을 받아야 한다. 그러나 기존의 Mobile IP에서는 키 분배 문제를 고려하지 않고 메시지 인증만을 다루고 있으며 [2,3]에서는 등록 키를 생성하기 위하여 몇 가지 방법을 제시하고 있지만 구체적인 인증 프로토콜은 다루지 않고 있다. 본 논문에서는 Mobile IP 환경에서의 와 간에 공개키 기반 인증 프로토콜을 제안한다. 제안된 인증 프로토콜은 와 간의 상호 인증 단계를 거치며, 서로간에 비밀 세션키를 생성하여 데이터의 기밀성을 보장할 수 있다. 또한 공개키에 기반 하므로 전자서명을 통한 메시지의 부인방지 기능을 얻을 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1419-1420
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• 2009

SCTP(Stream Control Transmission Protocol)는 새로운 전송계층 프로토콜로 TCP와 UDP의 장점을 결합한 대체 프로토콜로 기대되고 있다. 다양한 환경에서의 연구와 함께 SCTP에서 보안서비스를 제공하는 보안메커니즘에 관한 연구도 활발히 진행되고 있다. SCTP를 위한 E2E 보안메커니즘은 대부분 4계층 이상에서의 보안서비스를 결합한 방식으로 제안되고 있으며, IP계층에서의 보안을 위한 IPSEC은 멀티호밍의 특성을 적절히 지원하지 못하고 있다. 그래서 IP계층에서의 IP주소인증 및 IP패킷의 보안서비스 제공을 위한 보안메커니즘이 요구된다. 본 논문에서는 멀티호밍의 SCTP에서 각 IP주소를 인증하고 비밀키를 공유하는 인증메커니즘을 제안한다.

• The Journal of Society for e-Business Studies
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• v.16 no.3
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• pp.159-168
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• 2011

To identify fraud clicks in the Internet advertisement, existing studies have considered keyword, visit time, and client IP as an independent variable for the standard. These methods have limitations in identifying the fraud clicks that utilize automation tools, for they are methods based on client IP and human activities on the Internet. This paper proposes that fingerprinting values of the variable combination should be used to identify fraud clicks. The proposed model is composed of 3 stages and the fingerprinting values are compared with the other input data at each stage; IP fingerprinting in the first stage, IP and session data fingerprinting in the second stage, and session data and keyword fingerprinting in the third stage. We showed that the proposed model of the fraud click identification is more correct than existing methods through experiments according to the proposed scheme.

• Journal of Internet Computing and Services
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• v.11 no.2
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• pp.85-98
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• 2010

An advanced and proactive response mechanism against diverse attacks on All-IP network should be proposed for enhancing its security and reliability on open network. There are two main research works related to this study. First one is the SPIE system with hash function on Bloom filter and second one is the Sinkhole routing mechanism using BGP protocol for verifying its transmission path. Therefore, advanced traceback and network management mechanism also should be necessary on All-IP network environments against DDoS attacks. In this study, we studied and proposed a new IP traceback mechanism on All-IP network environments based on existing SPIE and Sinkhole routing model when diverse DDoS attacks would be happen. Proposed mechanism has a Manager module for controlling the regional router with using packet monitoring and filtering mechanism to trace and find the attack packet's real transmission path. Proposed mechanism uses simplified and optimized memory for storing and memorizing the packet's hash value on bloom filter, with which we can find and determine the attacker's real location on open network. Additionally, proposed mechanism provides advanced packet aggregation and monitoring/control module based on existing Sinkhole routing method. Therefore, we can provide an optimized one in All-IP network by combining the strength on existing two mechanisms. And the traceback performance also can be enhanced compared with previously suggested mechanism.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4B
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• pp.298-305
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• 2003

In this paper, we proposed a high performance lookup controller for IP packet forwarding engine of ATM based label edge routers. The lookup controller is designed to provide services such as MPLS, VPN, ELL, and RT services as well as the best effort. For high speed searching for IP addresses, we employed a TCAM based hardware search device not using traditional algorithmic approaches. We also implement lookup control functions into FPGA for fast processing of packet header and lookup control. The proposed lookup controller is designed to support differenciated services for users and to process in pipelined mechanism for performance improvement. A two-step search scheme is also applied to perform lookup for the key combined with multi-field of packet header. We found that the proposed lookup controller provides the performance of about 16M packets per second through simulations.

• Journal of Soil and Groundwater Environment
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• v.25 no.2_spc
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• pp.86-100
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• 2020

Analyzing and monitoring environmental contaminants based on geophysical exploration techniques have become important and it is now widely applied to delineate spatial distribution geophysical characteristics in wide area. Among the techniques, induced polarization (IP) method, which measures polarization effects on electrical potential distribution, has drawn much attention as an effective tool for environmental monitoring since IP is sensitive to changes in biochemical reactions. However, various reactions stemming from the presence of multiple contaminants have greatly enhanced heterogeneity of polluted sites to result in highly variable electrical characteristics of the site. Those contaminants influence chemical and physical state of soil and groundwater to alter electrical double layer, which in turn influences polarization of the media. Since biochemical reactions between microbes and contaminants result in various IP effects, IP laboratory experiments were conducted to investigate IP responses of the contaminated soil samples under various conditions. Field IP surveys can delineate the spatial distribution of contamination, while providing additional information about electrical properties of a target medium, together with DC resistivity. Reviewing IP effects of contaminants as well as IP surveys can serve as a good starting point for the application of IP survey in site assessment for environmental remediation.