• 대한공업교육학회지
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• v.33 no.2
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• pp.232-247
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• 2008

Timely collaboration among businesses is required these days such as in B2B E-Commerce. That is, emergency requests or urgent information among businesses should be processed in an immediate mode. In this paper we investigate the semantics on timing constraints of timely collaboration among businesses in terms of event, data, and action and present ECA rule construction related to the timing constraints and its violation. The prototype is implemented using web-based active functionality component.

• Information and Communications Magazine
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• v.30 no.4
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• pp.46-52
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• 2013

본고에서는 통신 시스템을 이루는 노드들 간의 협력 통신을 정보이론적 관점에서 살펴본다. 특히 여러 가지 협력 통신 모델 중 가장 간단한 모델인 릴레이 채널에 대해 현재까지 발표된 여러 기법들을 소개하고, 각각을 통해 얻을 수 있는 전송량을 살펴본다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.95-101
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• 2009

Wireless Sensor Network (WSN) has limited power and bandwidth. In order to high data rate and high speed communication systems are required. Cooperative communication system can help to decrease power consumption through spatial diversity. In cooperative transmission, one partner node assists one sensor node to transmit their data to destination. Instead of using M partners for M sensor nodes, we propose 1 partner for M sensor nodes. And we proposed relay selection scheme base on ARQ. Proposed protocol offers higher diversity order as conventional one with much less bandwidth and power. The destination will consider the one packets received from the best relay to reduce the complexity of the system. We verified BER performance for the proposed protocol through Monte-Carlo simulation over Rayleigh fading plus AWGN.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.33-39
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• 2012

Official Development Assistance(ODA) Project is initiated to assist a developing country economically and to promote its welfare. Support on training and information system development are the primary elements in the maritime safety field. The maritime safety information system(MSIS) of ODA projects deals with maritime safety information of developing nations and ensures an inter-operability between other systems. Therefore, it is required to develop MSIS based on the Universal Hydrographic Data Model(UHDM) of International Hydrographic Organization(IHO). In this paper, we have analyzed the current status and operational process of UHDM established by IHO. Oil spill response system was selected as an example of MSIS project and, also, considered the application results to the maritime safety field of UHDM.

• Journal of KIISE:Software and Applications
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• v.31 no.12
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• pp.1672-1683
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• 2004

Recommender system is a kind of web intelligence techniques to make a daily information filtering for people. Researchers have developed collaborative recommenders (social recommenders), content-based recommenders, and some hybrid systems. In this paper, we introduce a new hybrid recommender method - ICHM where clustering techniques have been applied to the item-based collaborative filtering framework. It provides a way to integrate the content information into the collaborative filtering, which contributes to not only reducing the sparsity of data set but also solving the cold start problem. Extensive experiments have been conducted on MovieLense data to analyze the characteristics of our technique. The results show that our approach contributes to the improvement of prediction quality of the item-based collaborative filtering, especially for the cold start problem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11A
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• pp.861-869
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• 2011

In this paper, we propose coordinated scheduling and beamforming based on limited feedback to overcome the effects of inter-cell interference in multi-cell environment. The goal of this study is to improve a performance of cell-edge area significantly affected by the inter-cell interference and also to guarantee a performance of the entire system. Existing coordinated scheduling and beamforming based on the perfect channel state information generates an overhead for the channel state information feedback and exchange at the users and base stations, respectively. In this study, first we propose a novel codebook to obtain a null space of an interference channel efficiently which can be used to reduce the inter-cell interference. Using the proposed codebook, we propose coordinated scheduling and beamforming to improve the performance of cell-edge area and the entire system. Through the proportional fair scheduling, the performance of the proposed technique is shown as improvement of channel capacity for users located cell-edge area and entire system.

• Journal of Broadcast Engineering
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• v.18 no.1
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• pp.88-97
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• 2013

Collaborative filtering(CF) for the personalized recommendation is a successful and popular method in recommender systems. But the mainly researched and implemented cases focus on dealing with independent items with explicit feedback by users. For the domain of TV program recommendation in VOD service platform, we need to consider the unique characteristic and constraints of the domain. In this paper, we studied on the way to convert the viewing history of each TV program episodes to the TV program preference by considering the series structure of TV program. The former is implicit for personalized preference, but the latter tells quite explicitly about the persistent preference. Collaborative filtering is done by the unit of series while data gathering and final recommendation is done by the unit of episodes. As a result, we modified CF to make it more suitable for the domain of TV program VOD recommendation. Our experimental study shows that it is more precise in performance, yet more compact in calculation compared to the plain CF approaches. It can be combined with other existing CF techniques as an algorithm module.

• Journal of the Korean Society for information Management
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• v.22 no.1 s.55
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• pp.209-228
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• 2005

This study is a preliminary work in examining how to manage resources for collaboratively interactive help systems. The purpose of this article is to describe significant patterns of behaviors and cognitive state in collaborative problem-solving situation, and further to explore the relationship between the behavior and the perception of service evaluation. Based on the concept of 'cognitive motion' in Dervin's Sense-Making theory, this study conducted a time-line interview. The sample of this study consists of 22 IT personnel helping other person solve IT problems and 36 users being helped for a IT problem-solving. This study presents a model of collaborative problem-solving behaviors and discusses some implications for designing help systems which collaborative interactions can happen.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.12
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• pp.455-462
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• 2014

In recent years, various services in mobile environments due to the growth of mobile devices and related techniques like wireless networks. Furthermore, as the increasing communication traffic in cellular networks has become a new significant issue, many studies for device-to-device(D2D) communication and D2D-based cooperative services have been performed recently. In this paper, we design a smart agent system for D2D-based cooperative services and propose a dynamic service binding method based on service ontology. We classify roles of mobile devices for cooperative services by defining three types of smart agents, and construct a knowledge base in order to describe properties of 'service' unit. The proposed knowledge model, D2D cooperative service ontology, can enable a autonomous cooperative services between mobile devices by binding a requested service to the appropriate member device according to the real-time context in mobile environments.

• Journal of Internet Computing and Services
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• v.12 no.2
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• pp.1-8
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• 2011

In this paper, we propose an effective method for cooperative spectrum sensing in cognitive radios where cognitive user(CR) with the highest reliability sensing data is only selected and allowed to report its local decision to FC as only decision making node. The proposed scheme enables CR users to implicitly compare their sensing data reliabilities based on their likelihood ratio, without any collaboration among cognitive radio users. Due to the mechanism, the proposed cooperative scheme can achieves a high spectrum sensing performance while only requiring extremely low cooperation resources such as signaling overhead and cooperative time in comparison with other existing methods such as maximum ratio combination (MRC) based, equal gain combination (EGC) based and conventional hard combination based cooperative sensing methods.