• 컴퓨터교육학회논문지
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• 제10권3호
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• pp.57-66
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• 2007

전자메일(e-mail)시스템은 인터넷을 통해 개인의 정보를 전달하는 매체로 가장 많이 사용된다. 그러나 송신자의 위변조 및 다수 사용자에게 메일을 전송하는 기법 등을 이용한 전자메일의 역기능 또한 늘어나고 있는 추세이다. 본 논문에서는 송신자의 위변조를 막기 위해 보안카드를 이용한 송신자 인증 기법을 제안 한다. 송신자는 메일 전송시 보안카드의 특정 코드번호를 송신자의 메일 서버로부터 요청 받는다. 송신자는 메일 서버로부터 요청 받은 코드 번호를 입력해 송신자 인증 절차를 거친 후 세션키를 생성한다. 생성된 세션키는 송신자의 서명 및 메시지를 안전하게 전송할 수 있는 암호화 키로 사용된다. 제안한 기법은 송신자 인증과 송신자 서명 및 메시지 암호화를 통해 기존의 스팸 방지 기법 보다 더욱 안전한 인증 구조를 제공한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.605-607
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• 2012

본 논문에서는 새로운 TCP Reset 공격방법에 대해 제시한다. TCP의 3-way Handshake 과정에서 Receiver가 listen 상태일 때, 부정확한 ACK Number를 포함하는 세그먼트를 받게 되면 Sender TCP에게 Reset을 포함한 세그먼트를 전송하여 연결 설정이 이루어 지지 않는다(RFC 792). 본 연구에서 는 TCP 초기 연결 설정 과정인 3-way Handshake에서 Sender를 모니터링 하고 있는 Attacker가 Sender보다 먼저 부정확한 ACK Number를 포함하는 세그먼트를 보내고, 이를 수신한 Receiver가 Sender에게 Reset을 포한한 세그먼트를 보내어 연결 설정이 이루어지지 않는 새로운 TCP Reset 공격 방법을 제시한다.

• 한국식생활문화학회지
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• 제21권5호
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• pp.536-540
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• 2006

The purposes of this study were 1) to analyze the correlation between Word-of-Mouth(WOM) message sender credibility and WOM effect and 2) to analyze the differences of WOM message sender creadibility and WOM effect in off-line and on-line WOM communication. The messages were created as a form of scenario for this study. Respondents were asked to evaluate the message sender credibility and predict WOM behaviors after reading given scenario. The questionnaires were distributed to 200 customers and a total of 175 questionnaires were used for analysis(87.5%). The statistical analysis was conducted using SPSS Win(12.0) for descriptive analysis, paired t-test, factor analysis, correlation analysis. The positive off-line WOM message sender was considered as more credible(p<.001) than on-line WOM message sender. 'Message sender credibility' is correlated with 'attitude formation' in both channels, but 'reliable' factor of 'credibility' variable is not significantly correlated with 'attitude change'.

• 한국콘텐츠학회논문지
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• 제10권11호
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• pp.48-57
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• 2010

기존의 우편 영상의 인식 연구는 수신인의 주소 정보를 인식하는데 초점이 맞춰 있었다. 상대적으로 발송인의 주소 정보를 인식하려는 연구는 적었다. 다량우편물 발송 업체의 우편물의 인쇄품질 검증 처리 및 반송 처리 등 송신자 정보를 이용한 서비스 및 응용을 위하여 송신자 정보의 인식 연구는 필요하다. 이 논문은 SIFT (Scale Invariant Feature Transform)을 이용하여 우편 영상의 송신자를 인식하는 방법을 제안하고 인식 실험을 하였다. SIFT 방법은 우수한 인식률을 보이나 등록한 모델수에 비례하여 keypoint들을 매칭하는데 소요하는 시간도 증가하는 시간 문제와 우편 영상의 특성상 서로 다른 모델일지라도 유사한 keypoint가 많아 오인식되는 문제가 있었다. 이를 해결하기 위해 거리함수를 추가한 SIFT를 제안하고 시간과 성능을 비교 실험 하였다. 또한 모델을 등록하는 수작업 과정 없이 자동으로 모델을 등록하고 분류하는 방법도 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.3231-3249
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• 2014

Deniable encryption, introduced in 1997 by Canetti, Dwork, Naor, and Ostrovsky, guarantees that the sender or the receiver of a secret message is able to "fake" the message encrypted in a specific ciphertext in the presence of a coercing adversary, without the adversary detecting that he was not given the real message. Sender - side deniable encryption scheme is considered to be one of the classification of deniable encryption technique which defined as resilient against coercing the sender. M. H. Ibrahim presented a sender - side deniable encryption scheme which based on public key and uncertainty of Jacobi Symbol [6]. This scheme has several problems; (1) it can't be able to derive the fake message $M_f$ that belongs to a valid message set, (2) it is not secure against Quadratic Residue Problem (QRP), and (3) the decryption process is very slow because it is based dramatically on square root computation until reach the message as a Quadratic Non Residue (QNR). The first problem is solved by J. Howlader and S. Basu's scheme [7]; they presented a sender side encryption scheme that allows the sender to present a fake message $M_f$ from a valid message set, but it still suffers from the last two mentioned problems. In this paper we present a new sender-side deniable public-key encryption scheme with fast decryption by which the sender is able to lie about the encrypted message to a coercer and hence escape coercion. While the receiver is able to decrypt for the true message, the sender has the ability to open a fake message of his choice to the coercer which, when verified, gives the same ciphertext as the true message. Compared with both Ibrahim's scheme and J. Howlader and S. Basu's scheme, our scheme enjoys nice two features which solved the mentioned problems: (1) It is semantically secure against Quadratic Residue Problem; (2) It is as fast, in the decryption process, as other schemes. Finally, applying the proposed deniable encryption, we originally give a coercion resistant internet voting model without physical assumptions.

• International Journal of Contents
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• 제3권1호
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• pp.34-38
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• 2007

Load redistribution is a critical resource in computer system. In sender-initiated load redistribution algorithms, the sender continues to send unnecessary request messages for load transfer until a receiver is found while the system load is heavy. These unnecessary request messages result in inefficient communications, low CPU utilization, and low system throughput in distributed systems. To solve these problems, we propose a genetic algorithm based approach for improved sender-initiated load redistribution in distributed systems. Compared with the conventional sender-initiated algorithms, the proposed algorithm decreases the response time and task processing time.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제2권1호
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• pp.59-64
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• 2002

In the sender-initiated load balancing algorithms, the sender continues to send an unnecessary request message fur load transfer until a receiver is found while the system load is heavy. Meanwhile, in the receiver-initiated load balancing algorithms, the receiver continues to send an unnecessary request message for load acquisition until a sender is found while the system load is light. These unnecessary request messages result in inefficient communications, low CPU utilization, and low system throughput in distributed systems. To solve these problems, in this paper, we propose a genetic algorithm based approach fur improved sender-initiated and receiver-initiated load balancing. The proposed algorithm is used for new adaptive load balancing approach. Compared with the conventional sender-initiated and receiver-initiated load balancing algorithms, the proposed algorithm decreases the response time and increases the acceptance rate.

• International Journal of Contents
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• 제2권1호
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• pp.39-44
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• 2006

Load sharing is a critical resource in computer system. In sender-initiated load sharing algorithms, the sender continues to send unnecessary request messages for load transfer until a receiver is found while the system load is heavy. Meanwhile, in the receiver initiated load sharing algorithms, the receiver continues to send an unnecessary request message for load acquisition until a sender is found while the system load is light. These unnecessary request messages result in inefficient communications, low CPU utilization, and low system throughput in distributed systems. To solve these problems, we propose a genetic algorithm based approach for improved sender-initiated and receiver-initiated load sharing in distributed systems. And we expand this algorithm to an adaptive load sharing algorithm. Compared with the conventional sender-initiated and receiver-initiated algorithms, the proposed algorithm decreases the response time and task processing time.

• Journal of Information Technology Applications and Management
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• 제20권2호
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• pp.127-146
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• 2013

The online social networking services (SNS) have been growing as the means of communication. In this study, we investigated word-of-mouth (WOM) effect under the SNS environment and evaluated the impact of message sender's influence on the WOM effect. Especially, this study focused on the betweenness centrality calculated through the social network analysis (SNA) of SNS network information, and proposed it as the measure of WOM message sender's influence, SNA may provide more accurate and objective measures than subjective self-reporting survey method. Fifty-one Facebook users responded to each of their four Facebook friends, who had been selected based on their betweenness centrality, Statistical analyses were performed using the responses and the betweenness centralities of the Facebook friends. The results showed that the direction (positive vs, negative) of a WOM message in SNS had an impact on the attitude of the message receiver toward the product. Moreover, the betweenness centrality of the message sender as well as his/her opinion leadership had a moderating effect on the WOM effect. Opinion leadership is a measure that has been frequently used for indicating the influence of WOM message sender in the previous studies. Considering the result that the betweenness centrality of the message sender was Significantly correlated to his/her opinion leadership, the betweenness centrality can be used for indicating the influence of WOM message sender.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.4011-4027
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• 2021

Cloud Computing has emerged as an extensively used technology not only in the IT sector but almost in all sectors. As the nature of the cloud is distributed and dynamic, the jeopardies present in the current implementations of virtualization, numerous security threats and attacks have been reported. Considering the potent architecture and the system complexity, it is indispensable to adopt fundamentals. This paper proposes a secure authentication and data sharing scheme for providing security to the cloud data. An efficient IPSO-KELM is proposed for detecting the malicious behaviour of the user. Initially, the proposed method starts with the authentication phase of the data sender. After authentication, the sender sends the data to the cloud, and the IPSO-KELM identifies if the received data from the sender is an attacked one or normal data i.e. the algorithm identifies if the data is received from a malicious sender or authenticated sender. If the data received from the sender is identified to be normal data, then the data is securely shared with the data receiver using SHA256-RSA algorithm. The upshot of the proposed method are scrutinized by identifying the dissimilarities with the other existing techniques to confirm that the proposed IPSO-KELM and SHA256-RSA works well for malicious user detection and secure data sharing in the cloud.