• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권2호
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• pp.405-424
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• 2013

In publishing applications, it is advantageous to embed data in halftone images. The CPT scheme (Chen-Pan-Tseng, 2000) is a steganographic data hiding scheme that was proposed for binary images, e.g., facsimiles. The CPT scheme uses a secret key and weight matrix to protect the hidden data and can hide as many as $r={\lfloor}{\log}_2(m{\times}n+1){\rfloor}$ bits of data in the image by changing at most 2 bits in the image. Our proposed scheme also uses a secret key to protect it from being compromised and a weight matrix to increase the data hiding rate. Our scheme improves the performance of the CPT scheme by using the simple principle of splitting each block into two parts. Our proposed scheme is called improved CPT (ICPT) and has a very high embedding capacity compared to previous schemes. Experimental results demonstrate that our proposed scheme generally has higher performance than previous schemes.

• International Journal of Contents
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• 제7권1호
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• pp.8-13
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• 2011

For energy-efficiency in Wireless Sensor Networks (WSNs), when a sensor node detects events, the sensing period for collecting the detailed information is likely to be short. The lifetime of WSNs decreases because communication modules are used excessively on a specific sensor node. To solve this problem, the TARP decentralized network packets to neighbor nodes. It considered the average data transmission rate as well as the data distribution. However, since the existing scheme did not consider the energy consumption of a node in WSNs, its network lifetime is reduced. In this paper, we propose an energy awareness congestion control scheme based on genetic algorithms in WSNs. The proposed scheme considers the remaining amount of energy and the transmission rate on a single node in fitness evaluation. Since the proposed scheme performs an efficient congestion control, it extends the network lifetime. In order to show the superiority of the proposed scheme, we compare it with the existing scheme through performance evaluation. It is shown that the proposed scheme enhances the data fairness and improves the network lifetime by about 27% on average over the existing scheme.

• 한국실내디자인학회논문집
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• 제19권5호
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• pp.105-112
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• 2010

The purpose of this study is to suggest the color scheme based on the color image types through the color analysis of workstation furniture which is on the market. This color scheme of the workstation furniture is expected to be give the comfort to office environment when planning office. For this study, It is selected the three furniture firms that have a brand of office furniture and their web site that is showed color sample of furniture. The following researches are drawn based upon the purpose. First, the color image types of interior space is classified and the color image words that are suitable for each types is extracted based on the results of existing literature. Second, the distribution of its hue and tone is analysed after collecting the each firm's color sample of desk top, panel and chair. Third, the color image appearing in each furniture color is analysed by color image scale positioning. Forth, the color scheme of desk top, panel and chair is suggested by its color scheme palette. The result of this study is expected to help comfortable environment by providing the color scheme for selection of furniture color in work space. Not all color of each furniture is sufficient to be combined color scheme, the result is indicated that the color scheme of workstation by color image types is possible for color planning in office environment.

• 한국정보과학회논문지:시스템및이론
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• 제29권5호
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• pp.284-290
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• 2002

본 논문에서는 블록 암호 알고리즘을 사용하지 않는 새로운 인증 암호화 방법을 제안한다. 이 방법은 Horster-Michels-Petersen 인증 암호화 방법에 기반하고 있으며, Bao-Deng 서명암호화에 이용된 기법을 적용함으로써 전송자의 서명을 수신자 이외의 임의의 제삼자가 검증할 수 있는 특성을 지닌다. 제안된 방법은 블록 암호 알고리즘을 이용하지 않으므로 구현시 코드 크기를 줄일 수 있는 장점을 가지며, 블록 암호 알고리즘을 이용하는 Bao-Deng 방법과 거의 같은 정도의 계산량 및 통신량만을 필요로 한다. 또한 제안된 방법은 기밀성, 인증성, 부인방지 등 안전성 요건들을 만족시킨다.

• 한국문헌정보학회지
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• 제49권1호
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• pp.319-340
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• 2015

이 연구는 국립아시아문화전당 아시아문화정보원의 수집대상 문화자원을 효율적으로 관리하기 위한 분류체계를 제시하기 위하여 시도되었다. 아시아문화정보원의 목적과 수집정책 방향을 알아보고 문화자원의 특성과 범주를 파악하였다. 그리고 현재 실제로 사용하고 있는 HRAF 분류체계, UNESCO 문화지표, 민속아카이브의 분류검색, 한국향토문화전자대전의 콘텐츠목차 등 4개의 분류체계를 비교분석하였다. 이를 토대로 아시아정보원의 문화자원 분류체계의 원칙과 기준을 제시하고, 분류체계의 주제 전개는 문화적, 사회적, 자연적 영역 순으로 전개하였고, 주류는 16개의 항목으로 설정되었다.

• 교육녹색환경연구
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• 제2권1호
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• pp.29-48
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• 2002

This study is for achievement of the expected aim on establish principle colour scheme of exterior and interior school facilities. Also this study aims to utilization of the data which is need for educational colour scheme of school facilities basically. The result of this study is as follows; 1) Domestic case study in primary school colour value distributed middle and high level between 5R and 6Y, the case study of foreign colour scheme distributed low and middle level. 2) Domestic case study in middle school facilities colour scheme distributed same colour of R, YR and the chroma distributed between 1 to 4. 3) The case study of domestic and foreign high school colour scheme distributed that in cases of domestic the colour scheme distributed very loose style and foreign cases distributed same colour of RP to YR with middle and high level of value and low chroma. 4) Exterior school facilities colour scheme distributed in Busan is that N~5GY(value 8~9 and chroma 0~8) in main school building skin material colour, 0~4 value and 7.5~9 chroma in assistant skin material colour. 5) Interior school facilities colour scheme distributed same colour of B, BF, PB, RP, N, YR in class room and open classroom in school mainly.

• 디지털융복합연구
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• 제10권4호
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• pp.207-215
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• 2012

본 논문에서는 무선 모바일 애드 혹 네트워크상에서 스트리밍 미디어 서비스 향상을 위한 프록시 기반 캐싱 최적화 기법을 제안한다. 제안된 기법은 WLAN상에서 미디어 서버와 노드들 간의 통신을 위해 프록시를 사용하며, 프록시는 무선 엑세스 포인터 근처에 설치한다. 그리고 캐싱 최적화가 수행되도록 NFCO(non-full cache optimization)과 CFO(cache full optimization)기법을 제안한다. NFCO와 CFO는 프록시에서 스트리밍이 수행될 때 캐시의 성능을 최적화하기 위해 사용된다. 제안된 기법의 성능을 알아보기 위하여 본 논문에서는 제안된 기법과 서버-중심 스트리밍 기법, 그리고 전송율 왜곡 스트리밍 기법과의 성능을 비교 분석하였다. 그 결과 제안된 기법이 서버-중심 스트리밍 기법과 전송율 왜곡 스트리밍 기법에 비해서 최적화 성능이 우수함을 알게 되었다.

• 디지털산업정보학회논문지
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• 제10권1호
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• pp.81-87
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• 2014

Password-based authentication using smart card provides two factor authentications, namely a successful login requires the client to have a valid smart card and a correct password. While it provides stronger security guarantees than only password authentication, it could also fail if both authentication factors are compromised ((1) the user's smart card was stolen and (2) the user's password was exposed). In this case, there is no way to prevent the adversary from impersonating the user. Now, the new technology of biometrics is becoming a popular method for designing a more secure authentication scheme. In terms of physiological and behavior human characteristics, biometric information is used as a form of authentication factor. Biometric information, such as fingerprints, faces, voice, irises, hand geometry, and palmprints can be used to verify their identities. In this article, we review the biometric-based authentication scheme by Cheng et al. and provide a security analysis on the scheme. Our analysis shows that Cheng et al.'s scheme does not guarantee any kind of authentication, either server-to-user authentication or user-to-server authentication. The contribution of the current work is to demonstrate these by mounting two attacks, a server impersonation attack and a user impersonation attack, on Cheng et al.'s scheme. In addition, we propose the enhanced authentication scheme that eliminates the security vulnerabilities of Cheng et al.'s scheme.

• ETRI Journal
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• 제33권4호
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• pp.621-628
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• 2011

The redactable signature scheme was introduced by Johnson and others in 2002 as a mechanism to support disclosing verifiable subdocuments of a signed document. In their paper, a redactable signature based on RSA was presented. In 2009, Nojima and others presented a redactable signature scheme based on RSA. Both schemes are very efficient in terms of storage. However, the schemes need mechanisms to share random prime numbers, which causes huge time consuming computation. Moreover, the public key in the scheme of Johnson and others is designed to be used only once. In this paper, we improve the computational efficiency of these schemes by eliminating the use of a random prime sharing mechanism while sustaining the storage efficiency of them. The size of our signature scheme is the same as that of the standard RSA signature scheme plus the size of the security parameter. In our scheme, the public key can be used multiple times, and more efficient key management than the scheme of Johnson and others is possible. We also prove that the security of our scheme is reduced to the security of the full domain RSA signature scheme.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3171-3181
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• 2021

This research serves to advance the development of engineering computational fluid dynamics (CFD) computing efficiency for the analysis of pressurized water reactor (PWR) core using rod-type fuel assemblies with mixing vanes (one kind of typical PWR core). In this research, a CFD scheme based on the reconstruction of the initial fine flow field (RIF CFD scheme) is proposed and analyzed. The RIF scheme is based on the quantitative regulation of flow velocities in the rod-type PWR core and the principle that the CFD computing efficiency can be improved greatly by a perfect initialization. In this paper, it is discovered that the RIF scheme can significantly improve the computing efficiency of the CFD computation for the rod-type PWR core. Furthermore, the RIF scheme also can reduce the computing resources needed for effective data storage of the large fluid domain in a rod-type PWR core. Moreover, a flow-ranking RIF CFD scheme is also designed based on the ranking of the flow rate, which enhances the utilization of the flow field with a closed flow rate to reconstruct the fine flow field. The flow-ranking RIF CFD scheme also proved to be very effective in improving the CFD efficiency for the rod-type PWR core.