• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.3
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• pp.379-387
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• 2013

In large-scale wireless sensor networks, tremendous amount of dummy packets is usually accompanied by keeping location privacy of the communication source and destination against global eavesdropping. In our earlier work we designed a location privacy routing protocol, ELPR(End-node Location Privacy Routing) in which the generation of dummy packets at each idle time-slot while transferring data packets are restricted to only the nodes within certain areas of encompassing the source and destination, respectively. In this paper, it is given that ELPR provides various degrees of location privacy while PCM(Periodic Collection Method) allows the only fixed level. Simulation results show that as the number of nodes or data packets increases ELPR permits in terms of the number of generated packets more cost-effective location privacy than PCM.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.12
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• pp.1353-1358
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• 2014

Tremendous amount of dummy packets are generally generated for faking over a wireless sensor network so as to keep the location privacy of nodes on the communication paths against the global eavesdropping. In this paper, a scoped-flooding protocol is designed for transferring data between each source and mobile sink(aka, basestation) where, the only nodes within the scope are allowed to issue dummy packets at every idle time so that the location privacy of the nodes on the paths is kept and the amount of dummy packets is reduced to the extend of the flooding scope. The size of the flooding diameter can be taken into consideration of the privacy level and the communication cost. We design a detailed specification of the protocol and verify several properties.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.433-438
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• 2020

Nodes on a data communication path in a wireless network emit electro-magnetic waves whenever they transmit packets; thus, the path can be exposed and identified with capturing and analyzing a sequence of the signals emitted there. One of countermeasures against a malicious eavesdropper is to let certain nodes mimic the nodes on the data path in sending dummy packets. In this paper we propose a packet transfer protocol which establishes the shortest path between source-destination pair a time and restricts heavy generation of dummy packets. We verify the location-privacy of a node on the communication paths through simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1715-1722
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• 2010

In this paper we consider methods for selecting the next tracing node that take advantage of the history of traced positions during the packet-tracing. In the meantime, the proposed routing strategy that counters the tracing is to design the routing path is such a way that nodes on it are not close to the nodes whose location privacy is needed and zigzag or back-and-forth movements hardly take place. In simulations, the ratios of successful tracing were largely improved. It was shown that our routing scheme allows more data packets to be delivered to the destination while, enticing the tracer to move more long distances in the presence of multiple assets.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1349-1354
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• 2013

Sealing structure to prevent flowing hot gas into the driving device, located between the driving shaft and the liner of On-Off valve for controlling the hot gas flow path was studied. Wear occurs due to the constant movement of the driving shaft controlled by actuator on graphite as the sealing material. In this paper, the dynamic wear behavior in high temperature of graphite(HK-6) to be used as sealing material was evaluated. Reciprocating wear test was carried out for the graphite(HK-6) to the relative motion between shaft materials(W-25Re). The results of friction coefficient and specific wear rate according to contact load, sliding speed at room temperature and $485^{\circ}C$ considering the actual operating environment were evaluated. Through the SEM analysis of the worn surface, third body as lubricant films were observed and lubricant effect of third body was considered.

• 월간 기계설비
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• no.9 s.218
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• pp.68-69
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• 2008

도시가스시설 검사 처리 세부지침이 개선되었다. 개정된 주요 내용은 $\Delta$내압 기밀시험 실시방법 개선 $\Delta$전기방식 생략 $\Delta$사용자공급관 입상관 밸브 설치위치 개선 $\Delta$용접 및 비파괴시험 공정 입회범위 개선 $\Delta$방호구조물 설치기준 제정 $\Delta$사용자공급관 계통도 제출 $\Delta$완성검사 필증현장 발급대상 추가 등이다. 기타 자세한 내용은 대한설비건설협회 홈페이지(http://www.kmcca.or.kr) 공개자료실에 게재되어 있다.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.5
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• pp.9-15
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• 2017

In the Digital Age, All Data used in the Internet is Digitized and Transmitted and Received Over a Communications Network. Therefore, it is Important to Transmit Data with Confidentiality and Integrity, Since Digital Data may be Tampered with and Tampered by Illegal users. Steganography is an Efficient Method for Ensuring Confidentiality and Integrity Together with Encryption Techniques. I Propose a Hangul Steganography Method that Inserts a Secret Message based on a Changing Insertion Position and a Changing Eojeol Size in a Cover Medium. Considering the Insertion Capacity of 3.35% and the File Size Change of 0.4% in Hangul Text Steganography, Experimental Results Show that the Jaro_score Value needs to be Maintained at 0.946.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06c
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• pp.239-241
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• 2012

우리 군은 미래전을 대비하기 위해 각종 전술 응용정보체계의 막힘없는 전송과 통신망간 연동 요구를 충족시키고 미래 전장을 주도할 통신체계 구축을 목표로 전술정보통신체계(TICN) 개발을 추진 중이다. Ad-hoc 네트워크 기술을 사용하는 전술정보통신체계의 부체계인 전투무선체계는 전장 환경에서 운영되는 특수성으로 인해 기존의 전통적인 플랫한 Ad-hoc 네트워크와는 차별화된 계층형 Ad-hoc 네트워크 구조를 가진다. 또한 Ad-hoc 네트워크를 운용하는 환경이 보안성이 극도로 요구되는 전장 환경임을 고려할 때 군 작전의 성공적인 목표 달성을 위한 보안대책은 반드시 필요하다. 특히 전장상황 하에서 유통될 각종 민감 정보들에 대한 기밀성, 무결성 등을 보장하기 위해 정당한 권한을 가진 노드들만이 네트워크에 참여할 수 있는 보안 매커니즘이 적용되어야 하며, 이를 위해선 효율적인 키 관리 기법을 적용해야 한다. 본 논문에서는 비밀키, 노드위치, 해시인증 등의 정보를 이용한 3단계 인증절차 적용으로 Ad-hoc 네트워크 참여 노드의 인증을 강화하고, 통신환경에 따라 3가지 비밀키를 구분 사용하여 계층형 Ad-hoc 네트워크 구조에서 기밀성 보장을 강화하기 위한 키 관리 기법을 제안한다.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.1
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• pp.38-44
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• 2003

Performance demonstration with real flawed specimens has been strongly required for nondestructive evaluation of safety class components in nuclear power plant. Mechanical or thermal fatigue crack and intergranular stress corrosion cracking could be occured in the in-service nuclear power plant and mechanical fatigue crack was selected to study in this paper. Specimen was designed to produce mechanical fatigue flaw under tensile stress. The number of cycles and the level of stress were controlled to obtain the desired flaw roughness. After the accurate physical measurement of the flaw size and location, fracture surface was seal-welded in place to ensure the designed location and site. The remaining weld groove was then filled by using gas-tungsten are welding(GTAW) and flux-cored arc welding(FCAW). Results of radio graphic and ultrasonic testing showed that fatigue cracks were consistent with the designed size and location in the final specimens.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.6
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• pp.1271-1282
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• 2012

Recently, security incidents occur continuously, resulting in the leakages of a large amount of the company's confidential and private information. For these reasons, the security technologies such as the authentication and the access control in order to prevent the information leakage are attracting attention. In particular, location-based authentication that utilizes the user's current location information which is used an authentication factor. And it provides more powerful authentication by controlling the users who attempt to access and blocks internal information leakage path. However, location information must be handled safely since it is the personal information. The location based authentication scheme proposed in this paper enhances the stability of the process location information compared with existing relevant location-based authentication protocol. Also it strengthens the end-user authentication by using one-time password. In addition, the proposed scheme provides authentication to prevent information leakage and employs the concept of the user's physical access control. Resultingly, the proposed scheme can provide higher security than the previous studies, while guarantee to low communication cost.