• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.605-608
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• 2010

Ad-hoc 네트워크가 정상적으로 동작하기 위해서는 각 노드가 동등한 권한을 갖고 상호 협조할 때 원활한 통신이 가능하다. 신뢰성을 확보하기 위해 인증된 노드로만 네트워크가 구성이 가능하지만 인증만으로 악의적 행위를 하는 노드를 완전히 배제할 수 없으므로 이들의 행위가 네트워크 전체를 위험에 빠뜨릴 수 있다. 이를 탐지 및 배제해야만 더욱 안전하고 신뢰할 수 있는 네트워크를 유지할 수 있으나 이에 대한 연구는 상대적으로 미흡한 수준이다. 따라서 신뢰 관계에 있는 노드로 구성된 네트워크에서 이기적이거나 악의적인 노드를 탐지하고 배제시켜 결과적으로 네트워크의 안전성과 신뢰성를 유지하고 처리율을 향상시킬 수 있는 방법을 제안한다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.6151-6158
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• 2013

Radio frequency ablation (RFA) is an effective means of achieving local control of liver cancer. It is a particularly suitable mode of therapy for small and favorably located tumors. However, local progression rates are substantially higher for large tumors (>3.0 cm). In the current study, we report on a mathematical model based on geometric optimization to treat large liver tumors. A database of mathematical models relevant to the configuration of liver cancer was also established. The specific placement of electrodes and the frequency of ablation were also optimized. In addition, three types of liver cancer lesion were simulated by computer guidance incorporating mathematical models. This approach can be expected to provide a more effective and rationale mechanism for employing RFA in the therapy of hepatic carcinoma.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권8호
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• pp.1472-1491
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• 2011

As used product transactions are currently on the rise, the demand for transactions of secondhand digital content will grow in the future; thus, learning to make secure transactions while avoiding cyber attacks becomes an important issue. In this paper, we combine the new buyer's secret key, the new buyer's watermark to embed in resold digital content, and the reseller's encrypted watermark, which can prove legal ownership of the reseller. Using the privacy homomorphism property of RSA and exponential calculus, the original seller of digital content can verify the legality of the reseller and the new buyer. We also reduced the load of encryption/decryption digital content using a partial encryption/decryption algorithm to make our protocol more efficient and practical. In the proposed protocol, the seller is not able to conduct piracy and easily frame any other innocent secondhand buyer when a case of piracy is found. In fact, piracy can be clearly traced using the privacy homomorphism property of RSA and the embedded watermark mechanism. Further, in the proposed protocol, the seller himself can trace the piracy using exponential calculus. Since it is unnecessary to trust third party participation, the conspiracy problem is resolved and the new buyer is not required to participate in the dispute. Moreover, the seller, reseller and new buyer can simultaneously benefit from the secondhand transaction.

• 한국정보통신학회논문지
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• 제14권12호
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• pp.2716-2723
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• 2010

Ad-hoc 네트워크가 정상적으로 동작하기 위해서는 각 노드가 동등한 권한을 갖고 상호 협조할 때 원활한 통신이 가능하다. 신뢰성을 확보하기 위해 인증된 노드로만 네트워크가 구성이 가능하지만 인증만으로 악의적 행위를 하는 노드를 완전히 배제할 수 없으므로 이들의 행위가 네트워크 전체를 위험에 빠뜨릴 수 있다. 이를 탐지 및 배제해야만 더욱 안전하고 신뢰할 수 있는 네트워크를 유지할 수 있으나 이에 대한 연구는 상대적으로 미흡한 수준이다. 따라서 신뢰 관계에 있는 노드로 구성된 네트워크에서 이기적이거나 악의적인 노드를 탐지하고 배제시켜 결과적으로 네트워크의 안전성과 신뢰성을 유지하고 처리율을 향상시킬 수 있는 방법을 제안한다.

• Journal of Communications and Networks
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• 제15권1호
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• pp.31-37
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• 2013

Mobile ad hoc networks (MANET) refers to a network designed for special applications for which it is difficult to use a backbone network. In MANETs, applications are mostly involved with sensitive and secret information. Since MANET assumes a trusted environment for routing, security is a major issue. In this paper we analyze the vulnerabilities of a pro-active routing protocol called optimized link state routing (OLSR) against a specific type of denial-of-service (DOS) attack called node isolation attack. Analyzing the attack, we propose a mechanism called enhanced OLSR (EOLSR) protocol which is a trust based technique to secure the OLSR nodes against the attack. Our technique is capable of finding whether a node is advertising correct topology information or not by verifying its Hello packets, thus detecting node isolation attacks. The experiment results show that our protocol is able to achieve routing security with 45% increase in packet delivery ratio and 44% reduction in packet loss rate when compared to standard OLSR under node isolation attack. Our technique is light weight because it doesn't involve high computational complexity for securing the network.

• 한국정밀공학회지
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• 제20권3호
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• pp.149-156
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• 2003

The estimation of fatigue limit for the component with complicated shape is difficult than of standard fatigue specimen, due to complex test equipment. So, we substitute maximum principle stress from FEM results for fatigue limit diagram made by standard fatigue specimen. Then we can estimate endurance safety of component with high trust. The static stress analysis, the nonlinear contact stress analysis and the model analysis for turbine blade is performed by ANSYS ver. 5.6. the comparison of maximum static stress around hole with maximum contact stress between pun and hole can make the cause of fracture for turbine blade clear. The difference of fatigue limit between fatigue test by standard specimen and in-service mechanical components is due to surface roughness and machining condition etc. In in-service mechanical components, Goodman diagram has to consider surface roughness for failure analysis. To find fracture mechanism of torison-mounted blade in nuclear plant. This study performs the static stress, the nonlinear contact stress and the modal analysis on torison-mounted blade with finite element method and makes the estimation for safety of turbine blade.

• The Journal of Asian Finance, Economics and Business
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• 제6권2호
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• pp.183-187
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• 2019

The paper aims to provide some recommendations to improve the operational capacity of the Tra Vinh Provincial Center of Public Administrative Services and to improve the effectiveness and efficiency of management in the State administrative agencies. The study on people's satisfaction towards public services of Tra Vinh Provincial Center of Public Administrative Services was conducted by collecting primary data of 300 people who used public services provided by this Center from September 2018 to November 2018. By using the multivariate regression method, the author found that there were a number of factors affecting people's satisfaction towards public services at the Center, including procedures, service fee, and attitudes of the staff, empathy, staff capacity, and trust. These factors had an impact on people's satisfaction towards public administrative services performed by staff officers from Tra Vinh Provincial Center of Public Administrative Services. Since then, the study has proposed policy implications to improve people's satisfaction on service quality at the Center such as: Develop a flexible charge mechanism of public services; Enhance the sense of responsibility of staff officers; Pay attention to improving administrative procedures; Establish trustworthiness to people; Pay attention to professional improvement; and Build up a friendly and respectful team of staff.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2007년도 추계학술대회
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• pp.367-378
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• 2007

기업이나 단체는 고객과의 관계형성 강화와 충성도를 높이기 위해 온라인 커뮤니티를 조직 차원에서 활성화하고 있고, 개인들은 사회 연결망(social network) 강화를 위해 개인의 관심사${\cdot}$가치${\cdot}$흥미${\cdot}$문화 등에 따라 특정 온라인 커뮤니티 사이트를 통해서 다양한 정보 획득과 구성들 간의 관계를 형성해 가고 있다. 이러한 추세에 힘입어 온라인 커뮤니티 사용자들은 상호작용성을 높이기 위해 아바타를 커뮤니케이션의 전달매체로 활용하는 경향이 있다. 본 연구는 아바타가 웹사이트 간 신뢰전이에 어떻게 영향을 미치고, 아바타 유무와 아바타 유형에 따라 신뢰전이가 어떤 차이가 나는지를 실증분석을 통해 검증하였다. 첫째, SERI와 SERI 포럼 사이트간에 신뢰전이가 부분적으로 발생하고 있으며, SERI 포럼 내에서는 변수들간의 모든 가설이 모두 유의하게 검증되었다. 둘째, 아바타 유형에 따라 SERI와 SERI 포럼 사이트간에 신뢰전이가 발생하는데 차이가 나타났다. 셋째, 모(母) 사이트의 신뢰는 자(子) 사이트의 품질요인과 포럼활동 만족도에 직${\cdot}$간접적으로 일부분 영향을 미쳤다. 다만, 중개자 신뢰는 시스템신뢰에는 유의한 영향을 주지 못하며, 피드백 메커니즘은 정보 품질과 시스템품질에 유희한 영향을 주지 못한다.

• ETRI Journal
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• 제42권6호
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• pp.976-986
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• 2020

Internet of Things (IoT) is considered the future network to support wireless communications. To realize an IoT network, sufficient spectrum should be allocated for the rapidly increasing IoT devices. Through cognitive radio, unlicensed IoT devices exploit cooperative spectrum sensing (CSS) to opportunistically access a licensed spectrum without causing harmful interference to licensed primary users (PUs), thereby effectively improving the spectrum utilization. However, an open access cognitive IoT allows abnormal IoT devices to undermine the CSS process. Herein, we first establish a hard-combining attack model according to the malicious behavior of falsifying sensing data. Subsequently, we propose a weighted sequential hypothesis test (WSHT) to increase the PU detection accuracy and decrease the sampling number, which comprises the data transmission status-trust evaluation mechanism, sensing data availability, and sequential hypothesis test. Finally, simulation results show that when various attacks are encountered, the requirements of the WSHT are less than those of the conventional WSHT for a better detection performance.

• Asian Journal of Business Environment
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• 제11권1호
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• pp.27-37
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• 2021

Purpose: This article aims to provide a balanced understanding of the structural conditions and social processes involved in the creation and diffusion of innovation. Research design, data and methodology: Drawing on organizational and economic sociology and strategic management literature, this article offers a conceptual framework that highlights the two dimensions of network structures: the vertical dimension focusing on power and legitimacy vs. the horizontal dimension highlighting information value. By organizing the literature on the functions and consequences of network, this paper advances a theoretical perspective in understanding the vast array of empirical studies on innovation involving network analysis. Results: Using the proposed framework, this article explains how the mechanisms of power, legitimacy, and information value work together with social structural factors, thus enriching our understanding of innovation. This study reveals that the information mechanism (horizontal dimension) has been most important in innovation creation and diffusion, and that trust, credibility, and legitimacy are operative in innovation diffusion. Conclusions: This paper contributes to the literature by responding to calls to extend existing frameworks to better account for the dynamics between innovation and network. In addition, this article highlights how conceptualizing innovation within the horizontal-vertical dimensions of network structures, creates new opportunities for future research.