• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.1144-1156
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• 2014

In Internet, IP multicast has been used successfully to provide an efficient, best-effort delivery service for group communication applications. However, applications such as multiparty private conference, distribution of stock market information, pay per view and other subscriber services may require secure multicast to protect integrity and confidentiality of the group traffic, and validate message authenticity. Providing secure multicast for group communication is problematic without a robust group key management. In this paper, we propose a group key management scheme based on the secret sharing technology to require each member by itself to generate the group key when receiving a rekeying message multicast by the group key distributor. The proposed scheme enforces mutual authentication between a member and the group key distributor while executing the rekeying process, and provides forward secrecy and backward secrecy properties, and resists replay attack, impersonating attack, group key disclosing attack and malicious insider attack.

• Journal of Communications and Networks
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• 제15권1호
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• pp.54-60
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• 2013

In this paper, a novel method called location-based delivery (LBD), which combines the short message service (SMS) and global position system (GPS), is proposed, and further, a realistic system for tracking a target's movement is developed. LBD reduces the number of short message transmissions while maintaining the location tracking accuracy within the acceptable range. The proposed approach, LBD, consists of three primary features: Short message format, location prediction, and dynamic threshold. The defined short message format is proprietary. Location prediction is performed by using the current location, moving speed, and bearing of the target to predict its next location. When the distance between the predicted location and the actual location exceeds a certain threshold, the target transmits a short message to the tracker to update its current location. The threshold is dynamically adjusted to maintain the location tracking accuracy and the number of short messages on the basis of the moving speed of the target. The experimental results show that LBD, indeed, outperforms other methods because it satisfactorily maintains the location tracking accuracy with relatively fewer messages.

• 기술혁신학회지
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• 제13권1호
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• pp.1-27
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• 2010

본 논문에서는 진화론적 기술경제학을 토대로 우리나라 국가연구개발사업에 투입되는 정부연구비의 성과를 여섯 가지 분석요인을 가지고 다각도로 분석하였다. 분석에는 2008년 3월부터 서비스를 시작한 국가과학기술지식정보서비스(National Science and Technology Information Service, NTIS)를 활용하였다. NTIS에서 2002년부터 2008년까지 연도별로 과학기술표준분류, 연구수행주체, 경제사회목적, 협력행태에 따른 정부연구비를 조사하였고, 이를 "투입"으로 놓았다. 그리고 이와 유사하게 2002년부터 2008년까지의 연도별 과학기술표준분류, 연구수행주체, 경제사회목적, 협력행태에 따른 논문 성과, 특허 성과, 사업화 성과, 기술료 성과를 조사하였고, 이를 "성과"로 놓았다. 우리는 이 자료의 분석결과를 통해서 정부연구비의 성과에 영향을 미치는 여러 가지 요인을 파악할 수 있을 것으로 기대하였고, 이것으로부터 정부연구비 투입의 방향성 또는 정책적 시사점을 제시할 수 있을 것으로 기대하였다. 다만 보다 미시적인 관점에서 산업 또는 기술의 특성, 연구수행주체가 갖는 조직의 특성, 협력연구 형태에 따른 네트워크의 특성, 사회 정치 문화적 외부 효과 등의 요인을 고려하지 못한 점은 이 연구의 한계점이라고 할 수 있다.

• Journal of Information Science Theory and Practice
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• 제10권spc호
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• pp.12-24
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• 2022

This study attempted to investigate changes in collaboration structure for each stage of national Research and Development (R&D) in the artificial intelligence (AI) field through analysis of a co-author network for papers written under national R&D projects. For this, author information was extracted from national R&D outcomes in AI from 2014 to 2019. For such R&D outcomes, NTIS (National Science & Technology Information Service) information from the KISTI (Korea Institute of Science and Technology Information) was utilized. In research collaboration in AI, power function structure, in which research efforts are led by some influential researchers, is found. In other words, less than 30 percent is linked to the largest cluster, and a segmented network pattern in which small groups are primarily developed is observed. This means a large research group with high connectivity and a small group are connected with each other, and a sporadic link is found. However, the largest cluster grew larger and denser over time, which means that as research became more intensified, new researchers joined a mainstream network, expanding a scope of collaboration. Such research intensification has expanded the scale of a collaborative researcher group and increased the number of large studies. Instead of maintaining conventional collaborative relationships, in addition, the number of new researchers has risen, forming new relationships over time.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.83-86
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• 2004

With the proliferation of smart devices, applications under ubiquitous environment must provide transparent access to computer resources. However, existing u-Logistics systems can not properly react on such requirements, because the status information of objects is input only in fixed milestones by system's operators. In this paper, we introduce an event notification service suitable for u-Logistics environment. The system is based on RFID infrastructure and provides real-time tracking by combining the event of objects with location information received from GPS satellites. The system also provides a graphical user interface based on a state/transition approach, making it easy that clients facilitate definition of profile, and uses XML structure to more easily represent and exchange events.

• 한국컴퓨터정보학회논문지
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• 제23권12호
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• pp.233-240
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• 2018

In this study, variables were constructed based on prior research to examine the impact of information system quality (information quality, system quality, service quality), customer value and satisfaction in hotel comparison site. The samples consist of 205 survey data drawn from hotel comparison site users. The collected data were analyzed by SPSS 24.0 and AMOS 21.0. According to results of the reliability and validity test, all were found reliable, and all items were included. The results are as follows: first, Among the information system quality (information quality, system quality, and service quality) of the hotel comparison site, the information quality and service quality have positive effects on customer value. Second, the information system quality(information quality, system quality, and service quality) of the hotel comparison site has a positive effect on customer satisfaction. Third, the customer value of the hotel comparison site has a positive effect on customer satisfaction.

• 정보관리연구
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• 제37권3호
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• pp.61-84
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• 2006

본 논문은 시소러스 구축 시 직면하는 문제점과 구축방법을 비판적으로 검토하고, 여러 가지 구축 방법 중 직접구축 방법을 제안하였다. 또한, 확장검색의 효율성을 보장할 수 있는 시소러스 구축을 위해 의미적 준거인 개념패싯, 관계패싯 등의 도입과 활용을 도입하였으며, 이를 이용하여 구축한 과학기술분야 시소러스의 구축사례를 제시하였다. 특별히, 패싯이 반영된 시소러스에는 다양한 관점이 반영될 수 있으므로 검색의 효율성이 보장된다는 장점이 있고, 인접 과학기술분야에 응용될 수 있다. 일례로 본 시소러스는 과학기술 연구자들의 협업을 지원하기 위한 정보유통 서비스에 응용될 수 있으며, 향후 고도화된 지식 서비스에도 확장 응용될 수 있다.

• 방송공학회논문지
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• 제23권6호
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• pp.931-938
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• 2018

디지털케이블TV VOD 서비스는 시청자들이 원하는 쇼, 드라마, 영화 등 다양한 콘텐츠를 고화질로 시간과 장소에 구애받지 않고 제공한다. 실시간으로 제공하는 지상파방송 시청시간은 감소하는 반면, VOD에 대한 수요가 높게 나타나고 디지털 가입자가 확대됨에 따라 VOD 시장은 급성장하고 있다. 따라서 본 연구에서는 디지털케이블TV 가입자를 대상으로 연령과 성별 분석을 통해 인지도를 확인하고, VOD 서비스 이용자를 대상으로 이용행태와 시청사례를 분석하였다. 분석결과 다수의 이용자들이 리모컨 조작과 무료쿠폰을 통해 VOD 서비스를 처음 사용하기 시작한 것으로 나타났다. VOD 서비스 비이용자는 요금부담으로 사용하지 않으며 필요성을 느끼지 못한다는 응답이 있었지만, 일부 비이용자는 무료 VOD 서비스에 대한 것을 인지하지 못한 것으로 나타났다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1260-1283
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• 2019

Low earth orbit (LEO) satellite broadband network is a crucial part of the space information network. LEO satellite constellation design is a top-level design, which plays a decisive role in the overall performance of the LEO satellite network. However, the existing works on constellation design mainly focus on the coverage criterion and rarely take network performance into the design process. In this article, we develop a unified framework for constellation optimization design in LEO satellite broadband networks. Several design criteria including network performance and coverage capability are combined into the design process. Firstly, the quality of service (QoS) metrics is presented to evaluate the performance of the LEO satellite broadband network. Also, we propose a network stability model for the rapid change of the satellite network topology. Besides, a mathematical model of constellation optimization design is formulated by considering the network cost-efficiency and stability. Then, an optimization algorithm based on non-dominated sorting genetic algorithm-II (NSGA-II) is provided for the problem of constellation design. Finally, the proposed method is further evaluated through numerical simulations. Simulation results validate the proposed method and show that it is an efficient and effective approach for solving the problem of constellation design in LEO satellite broadband networks.

• Journal of Information Technology Applications and Management
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• 제26권1호
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• pp.1-19
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• 2019

The aim of this study is to assess the impacts of service properties, price expectancy, social influences, and switching costs on adoption intention of 4G in Vietnam. The research model was established by the theory of diffusion of innovation, technology acceptance model, service quality, social influences and switching costs. The result from customers using telecommunication services in Vietnam shows that adoption intention of 4G is affected directly by perceived usefulness, personal innovativeness, price expectancy, social influences, prior service quality and switching costs. Whereas, switching costs have negative effect on adoption intention. Other factors such as personal innovativeness, perceived ease of use and prior service quality have an indirect effect on adoption intention of 4G.