• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.128-132
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• 2011

In interference tolerance based spectrum sharing systems, primary receivers (PRs) are protected by a predefined peak or average interference power constraint. To implement such systems, cognitive radio (CR) transmitters are required to adjust their transmit power so that the interference power received at the PR receivers is kept below the threshold value. Hence, a CR-transmitter requires knowledge of its channel and the primary receiver in order to allocate the transmit power. In practice, it is impossible or very difficult for a CR transmitter to have perfect knowledge of this channel state information (CSI). In this paper, we investigate the impact of imperfect knowledge of this CSI on the performances of both a primary and cognitive radio network. For fixed transmit power, average interference power (AIP) constraint can be maintained through knowledge of the channel distribution information. To maintain the peak interference power (PIP) constraint, on the other hand, the CR-transmitter requires the instantaneous CSI of its channel with the primary receiver. First, we show that, compared to the PIP constraint with perfect CSI, the AIP constraint is advantageous for primary users but not for CR users. Then, we consider a PIP constraint with imperfect CSI at the CR-transmitter. We show that inaccuracy in CSI reduces the interference at the PR-receivers that is caused by the CR-transmitter. Consequently the proposed schemes improve the capacity of the primary links. Contrarily, the capacities of the CR links significantly degrade due to the inaccuracy in CSI.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.2
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• pp.127-132
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• 2002

All the countries in RA II (Asia Region in WMO) welcome the establishment of a Web site dedicated to agricultural meteorology, because it is believed that the best way to improve and speed up the flow of information is the use of the Internet and the establishment of a Web site. In providing recommendation for the promotion and improvement of the AgroMeteorological service in RA II, a couple of key suggestions were proposed: (a) Exchanges of data and AgroMeteorological knowledge between member countries and between RAs, (b) Exchanges of experts between member countries as a necessary way to share the knowledge, and (c) Joint research between member countries to solve common problems in AgroMeteorological affairs. In order to meet the above requirements for RA II, an AgroMeteorological information network will be the most critical and dynamic aspect in sustainable agriculture in this region. In addition, the establishment of a Core AgroMeteorological station, recommended by CAgM of WMO, will require its own information sharing systems for communication among member countries. Inevitable use of information technologies (IT) such as information networks, databases, simulation models, GIS, and RS for regional impact assessment of environmental change on AgroEcosystem will be enforced. Thus, the regional Internet-based Agrometeorological information network has been in place since 1999, though all contributions to it have been volunteered by individuals, institutes, universities, etc.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.249-255
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• 2014

Recently, creation and sharing of information make progress actively through the SNS(Social Network Service) such as twitter, facebook and so on. It is necessary to extract the knowledge from aggregated information and data mining is one of the knowledge based approach. Especially, emotion analysis is a recent subdiscipline of text classification, which is concerned with massive collective intelligence from an opinion, policy, propensity and sentiment. In this paper, We propose the emotion prediction method, which extracts the significant key words and related key words from SNS paragraph, then predicts the emotion using these extracted emotion features.

• Journal of Computing Science and Engineering
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• v.8 no.4
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• pp.181-186
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• 2014

Web data mining aims at discovering useful knowledge from various Web resources. There is a growing trend among companies, organizations, and individuals alike of gathering information through Web data mining to utilize that information in their best interest. In science, cloud computing is a synonym for distributed computing over a network; cloud computing relies on the sharing of resources to achieve coherence and economies of scale, similar to a utility over a network, and means the ability to run a program or application on many connected computers at the same time. In this paper, we propose a new system framework based on the Hadoop platform to realize the collection of useful information of Web resources. The system framework is based on the Map/Reduce programming model of cloud computing. We propose a new data mining algorithm to be used in this system framework. Finally, we prove the feasibility of this approach by simulation experiment.

• Journal of the Korea Society for Simulation
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• v.6 no.2
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• pp.31-44
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• 1997

In medical applications, the cooperation work using computer network is in the spotlight as next generation technology, because it offers sharing of equipments, knowledge of specialists, and data and surmounts the limitations of geographical position and time. We present a prototype of telepresent surgical simulation system in this treatise. It is a telemedicine system using volume image, which is reconstructed from radiological images such as MRI and CT. It is used as a tool for surgical simulation among telepresent doctors. It provides the functions of conference control, volume reconstruction and manipulation, and multimedia database management among one server and multi-clients through high-speed network. It is implemented on Unix workstation using X-windows and C language, TCP/IP protocol and UNiSQL as DBMS.

• International Journal of Computer Science & Network Security
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• v.23 no.2
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• pp.164-172
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• 2023

Sharing power data between electrical power grids is crucial in energy management. The multi-agent approach has been applied in various applications to improve the development of complex systems by making them both independent and collaborative. The smart grid is one of the most intricate systems that requires a higher level of independence, reliability, protection, and adaptability to user requests. In this paper, a multi-agent system is utilized to share knowledge and tackle challenges in smart grids. The shared information is used to make decisions that aid in power distribution management within the grid and with other networks. The proposed multi-agent mechanism improves the reliability of the power system by providing the necessary information at critical times. The results indicate that the multi-agent system operates efficiently and promptly, making it a highly promising candidate for smart grid management.

• The Journal of Society for e-Business Studies
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• v.21 no.2
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• pp.23-46
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• 2016

With the increasing socio-economic value of an open collaboration over the Internet, it has become significantly important to successfully manage open source software development program. Most of the previous research have focused on various factors that influence the performance of the project, but studies on how the project owners recognized as "leader" affect the outcome of the project are very limited. This research investigates how individual and governance characteristics of an owner influences the performance of project based on impression formation and social capital theory. For a data set, we collect 611 Repositories and the owner's data from the open source development platform Github, and we form knowledge sharing network of an each repository by using social network analysis. We use hierarchical regression analysis, and our results show that a leader, who exposes a lot of one's personal information or who has actively followed and showed interests to communicate with other developers, affects positive impacts on project performance. A leader who has a high centrality in knowledge sharing network also positively affects on project performance. On the other hand, if a leader was highly willing to accept external knowledge or is recognized as an expert in the community with large numbers of followers, the result show negative impacts on project performance. The research may serve as a useful guideline not only for the future open source software projects but also for the effective management of different types of open collaboration.

• Journal of the Korean Society for information Management
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• v.18 no.3
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• pp.63-86
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• 2001

Consumer health information is receiving more attention than ever before. This growing attention can be linked to the Internet and to people seeking more information on health topics. The purpose of this study is to suggest a design of the Knowledge management system for medical information services in a public library. As theoretical backgrounds, it discusses the issues regarding to the medical information services in a public library, knowledge management and knowledge management system. After that, 12 medical information sites are analyzed then the planning and the main menu of a medical information site for a public library are described. Finally, the model of the knowledge management system for a public library with 5 sub-systems are suggested: 1) knowledge creation system, 2) technology support system, 3) training system, 4) community service system, 5) knowledge sharing and network system. This system based on knowledge management will help provide the users high quality of medical information.

• Journal of Korea Multimedia Society
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• v.2 no.3
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• pp.355-365
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• 1999

In this paper, we present JPAS(Java Package for Array Sharing) which is a Java Package for sharing arrays of data on a cluster of workstations. It allows us to divide an array of data into several pieces, and to place each piece on a different host. JPAS uses Java RMI so that the entire array can be accessed by a location transparent interface which is similar to that of a distributed shared memory system. JPAS is portable and easy to use since it is implemented using pure Java. In order to reduce network overhead, JPAS allows programmers to use their prior knowledge of the application. Data consistency can be maintained through the value updating methods defined for all the elements of an array. We developed parallel programs which use JPAS, and tested them on a cluster of workstations. The test results show that JPAS is a parallel programming tool with reasonably good performance.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.348-362
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• 2010

In the Knowledge-based economy, it is inevitable for companies to implement knowledge management(KM in short) to improve management performance. In order to better understand the KM, it is necessary to examine the relationship between success factors of KM and KM performance in agribusiness sector. This study empirically analyzes the impact of success factors of Knowledge Management on companies' management performance in agribusiness cluster. From the survey data of 43 companies located in Sunchang fermented soybean products Industrial cluster, the study finds that four factors- learning culture, network, knowledge sharing and knowledge creating- influence management performance in a positive way. It also examines whether Industrial cluster strategy functions as a moderator between KM success factors and companies' performance. Furthermore, this study concludes that Sunchang fermented soybean Industrial cluster has not reached to the final stage of KM and suggests elements for further improvements.