• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.1
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• pp.67-80
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• 2007

Nateon Messenger, which has the most number of users in Korea, supports many services such as E-mail, note, Cyworld, SMS, etc. In this paper, we will analyse the authentication traffic which is transmitted and received by the Nateon Messenger. Through performing the replay attack with the authentication information, we will show that an attacker can be authenticated illegally. Furthermore, we will show that other domestic messengers have similar security problems.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.115-123
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• 2017

The mutual cooperation among nodes is very important because mobile nodes participating in MANET communicate with limited resources and wireless environment. This characteristic is important especially in environment that supports group communication. In order to support the secure multicast environment, it is important enough to affect performance to provide accurate authentication method for multicast group members and increase the integrity of transmitted data. Therefore, we propose a technique to provide the multicast secure communication by providing efficient authentication and group key management for multicast member nodes in this paper. The cluster structure is used for authentication of nodes in the proposed technique. In order to efficient authentication of nodes, the reliability is measured using a combination of local trust information and global trust information measured by neighboring nodes. And issuing process of the group key has two steps. The issued security group key increases the integrity of the transmitted data. The superiority of the proposed technique was confirmed by comparative experiments.

• Korean Journal of Human Ecology
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• v.19 no.1
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• pp.127-136
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• 2010

This research subdivided the groups of baby clothes purchasers by consumer value factors in order to study clothing behavior by the value group of baby clothes purchasers and to examine differences in shopping propensity, pursuit benefits, evaluation criteria, and utilization of information sources depending on the value groups 1. A total of three factors - the pursuit of a stable life, the pursuit of achievement, and the pursuit of pleasure - were derived by conducting a factor analysis on the value dimensions of baby clothes purchasers. The value types of baby clothes purchasers were classified into three groups - the group of the pursuit of achievement, the group of the pursuit of stability and pleasure, and the passive group as the result of conducting cluster analysis on the basis of three types of personal value factors. 2. In the difference of shopping propensity by the value group, the group of the pursuit of achievement and the group of the pursuit of stability and pleasure were found to be the group having economical shopping propensity. In the difference of pursuit benefits by the value group, the passive group appeared to be the group in pursuit of fashion, and it could be seen that the group of the pursuit of achievement and the group of the pursuit of stability and pleasure were highly interested in the pursuit of individuality and practicality. 3. In the evaluation criteria of clothes by the value group of baby clothes purchasers, the group of the pursuit of achievement was found to consider physical criteria as important evaluation criteria, and the group of the pursuit of stability and pleasure was found to consider aesthetic criteria as important evaluation criteria. In the utilization of information sources by the value group of baby clothes purchasers, the passive group was found to be influenced most by market-oriented information sources.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.07a
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• pp.43-46
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• 2003

At SIC 2001, Popescu proposed m efficient group signature scheme for large groups［1］. However, this paper shows that his scheme is to be insecure by presenting a signature forgery. Using our attack, anyone (not necessarily a group member) can forge a signature on a message m, and sine the attacker doesn't have to be the group member, the revocation manager cannot reveal the identity of the signer. Additionally, we modify Popescue's scheme to prevent the forgeary.

• Asia pacific journal of information systems
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• v.9 no.1
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• pp.143-163
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• 1999

This study investigates the effect of group size on group performance, here the quality of group decision, Four effects are proposed and tested in a field experimental setting : (1) the relationship between the group size and the distribution of individual's problem-solving ability ; (2) the change of the group decision quality as group size increases ; (3) the relationship between the group decision quality and the quality of the best/worst member as group size increases ; (4) the relationship between the group decision quality and the average quality of individuals in the group as group size increases. Data showed that contrary to the exiting results, group decision quality was not improved with the group size. Rather, it showed a little tendency that group decision quality was worsened with the group size. Data also showed that consensus-oriented group decision making process produced the compromised output. Thus, group decision quality was not better than the average group members'. The opinion of the best member was not accepted. The implications of the findings are discussed for the development of a Korean GSS.

• Journal of Korean Biological Nursing Science
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• v.9 no.2
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• pp.143-152
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• 2007

Purpose: The purpose of this study was to ascertain the effects of anesthetic information on preoperative state anxiety, plasma glucose, cortisol and epinephrine for patients under tonsillectomy and to provide generic data with anesthetic nursing intervention. Method: Data were collected from 60 patients who had tonsillectomy from November 1, 2003 to April 30, 2004. The group were divided into experimental group and control group: an experiment group of 30 patients was provided with an anesthetic information prepared by the researchers; a control group of another 30 patients was provided with general information. Data were analyzed through chi-squared test, t-test, repeated measure ANOVA using SPSS Program(version 12.0). Result: There were no significant difference between the experimental group and the control group in pre-operative state anxiety, glucose and cortisol. However, there were statistically significant difference between the above two groups in pre-operative pre-operative blood pressure(p=.001), heart beat(p=.000), and epinephrine(p=.035). Conclusion: The authors, with the results of this study, concluded that the preoperative anesthetic information for patients under tonsillectomy had direct effect on lessening pre-operative anxiety.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.912-928
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• 2019

Crowd behavior analysis research has revealed a central role in helping people to find safety hazards or crime optimistic forecast. Thus, it is significant in the future video surveillance systems. Recently, the growing demand for safety monitoring has changed the awareness of video surveillance studies from analysis of individuals behavior to group behavior. Group detection is the process before crowd behavior analysis, which separates scene of individuals in a crowd into respective groups by understanding their complex relations. Most existing studies on group detection are scene-specific. Crowds with various densities, structures, and occlusion of each other are the challenges for group detection in diverse crowded scenes. Therefore, we propose a group detection approach called Collective Interaction Filtering to discover people motion interaction from trajectories. This approach is able to deduce people interaction with the Expectation-Maximization algorithm. The Collective Interaction Filtering approach accurately identifies groups by clustering trajectories in crowds with various densities, structures and occlusion of each other. It also tackles grouping consistency between frames. Experiments on the CUHK Crowd Dataset demonstrate that approach used in this study achieves better than previous methods which leads to latest results.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.318-321
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• 2006

현재 국내 국책사업으로 추진 중인 와이브로(WiBro) 기술 규격이 포함되어 있는 휴대인터넷 표준 규격인 IEEE 802.16e는 IP기반으로, 이동성이 뛰어나고 고속전송 기능의 특징을 가지고 있다. 또한 기지국간의 핸드오버(Handover)를 지원함으로써 이동성을 지원한다. 그러나 이러한 핸드오버 기법에 있어서 Replay 공격, Man-in-the-Middle 공격, Stolen-Verifier 공격 등에 취약한 문제점이 드러나고 있다. 본 논문은 이러한 기존 핸드오버 기법의 취약점을 개선하기 위해서 사용자의 인증서와 Timestamp값을 통한 IEEE 802.16e/와이브로 망에서 안전한 핸드오버 적용 방안에 대해 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1425-1428
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• 2003

본 논문에서는 KRISTAL2000을 성능 향상시킨 KRISTAL2002의 특징을 간략히 소개하고 KRISTAL2002와 성능을 비교 분석한다. 개선된 부분 중에서 KRISTAL2000 시스템의 단점이었든 하나의 데몬으로 하나의 테이블 밖에 지원하지 못하던 기능을 KRISTAL2002에서는 하나의 데몬이 여러개의 테이블들을 검색 지원한다. 본 논문에서는 다중 테이블을 이용하여 KRISTAL2002의 성능을 실험하고 그 결과를 비교 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.1120-1123
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• 2008

단방향 암호화 함수인 해쉬 함수는 2005년 Wang의 새로운 공격법이 발표되면서 안전성에 대한 문제점이 조금씩 드러나기 시작하고 있다. Wang의 새로운 차분 공격법은 현재 가장 널리 사용하고 있는 해쉬 알고리즘인 SHA-1을 이론적으로 $2^{69}$의 계산으로 충돌을 찾을 수 있다고 하였다. 본 논문에서는 차분 공격이 이루어지는 방법과 Wang의 차분 공격이 지니는 두 가지 특성에 대해서 연구하였고, MDx계열의 해쉬 함수의 안전성에 대한 기존의 제시된 해결책과 다른, 한 블록의 모든 워드 값을 변형 처리한 방식을 제안한다.