• Journal of Communications and Networks
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• v.14 no.2
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• pp.140-150
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• 2012

In this paper, we investigate the optimal packet scheduling problem in a two-user multiple access communication system, where the transmitters are able to harvest energy from the nature. Under a deterministic system setting, we assume that the energy harvesting times and harvested energy amounts are known before the transmission starts. For the packet arrivals, we assume that packets have already arrived and are ready to be transmitted at the transmitter before the transmission starts. Our goal is to minimize the time by which all packets from both users are delivered to the destination through controlling the transmission powers and transmission rates of both users. We first develop a generalized iterative backward waterfilling algorithm to characterize the maximum departure region of the transmitters for any given deadline T. Then, based on the sequence of maximum departure regions at energy arrival instants, we decompose the transmission completion time minimization problem into convex optimization problems and solve the overall problem efficiently.

• The Journal of the Korea Contents Association
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• v.10 no.10
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• pp.26-35
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• 2010

Recently, multi client PC technologies that several users can use one set of computer at the same time are being designed to use the surplus computer resource. In general, as the existing PC management system considers only a single client PC that only one user uses a computer, various kinds of complicated problems may be arisen. This paper designs and realizes a remote management system that can monitor and control the information used in the windows based OS multi-client using WMI technology. The proposed system herein uses WMI technology and newly defined client management protocol and provides the monitoring and control functions on individual resource use information of multi-client. As well, it provides a communication function between the server and the client, and locking setting and access control functions.

• Proceedings of the KSRS Conference
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• v.1
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• pp.159-162
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• 2006

This paper describes the ground system for COMS (Communication, Ocean, and Meteorological Satellite), the first Korean multi-purposed geostationary satellite, at MSC (Meteorological Satellite Center) in Korea. The overview of COMS MI (Meteorological Imager) will be introduced as well. KMA would implement mission planning for COMS MI operation and receive, process, interpret, disseminate, and archive MI data operationally for domestic and foreign user groups. Major missions of COMS MI are mitigation of natural hazard such as typhoon, dust storm, and heavy rain, and short-term warning of severe weather to protect human health and commerce. Moreover, research of climate variability and long-term changes will be supported. In accordance with those missions, the concept and design of COMPASS (COMS operation and meteorological products application service system), the ground system for COMS MI in MSC, have been setting up since 2004. Currently, COMPASS design is being progressed and will have finished the end of 2006. The development of COMPASS has three phases: first phase is development of fundamental COMPASS components in 2007, second phase is to integrate and test all of the COMPASS components in 2008, and the last phase is to operate COMPASS after COMS In-Orbit Tests in 2009.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.6
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• pp.719-726
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• 1999

본 논문은 교통 신호 제어 알고리즘들의 성능을 비교하기 위한 복합교차로 시뮬레이터를 구현하였다. 기존의 교통 시뮬레이터들은 단일교차로를 대상으로 하거나 텍스트 모드로 동작하는 경우가 많았다. 논문의 시뮬레이터는 Visual C++의 MFC 라이브러리를 사용하여 n $\times$ n 형태를 갖는 복합교차로에 적합하도록 객체지향적으로 구현되었으며, 성능 비교를 위하여 제어 알고리즘들을 별개의 윈도우에서 처리하기 쉽도록 MDI 방식을 사용하였다. 개발한 시뮬레이터는 그래프 윈도우와 맵 윈도우의 편리한 사용자 인터페이스, 논리시간 설정을 통한 다목적 시뮬레이션, 다양한 성능평가 출력 등의 특징을 갖는다. Abstract In this paper, we implemented a multiple crossroad simulator to evaluate the performance of the traffic signal control algorithms. Most of existing traffic simulators were operated in text-mode or at a single intersection. We developed the object-oriented simulator suitable for multiple crossroads with n $\times$ n intersections by using MFC (Microsoft Foundation Class) library in Visual C++. The simulator was implemented by using MDI (Multiple Document Interface) scheme in order to process both control algorithms in separate windows respectively. Our simulator has the following features: user friendly interface with graph window and map window, multi-purpose simulations by setting logical time, and various forms of performance evaluation.

• Journal of the Korean Society for information Management
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• v.30 no.3
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• pp.297-315
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• 2013

Anyone curious to easily access and learn Korean history has become interested in Korean history data bases, which will provide accurate and reliable historical information. Furthermore, user demands for information sharing and reusability, available through setting up a semantic web, have been increased, which have taken the shape of linked data. Efforts have been made to construct public data bases containing readily usable contents a user can understand and utilize with ease. They have been produced by several organizations, portal sites, and individuals, trying to deviate from existing mainstreams - expert-based text data bases. A problem with those data bases is that they have not considered such vital factors as the sharing and utilizing of information as a whole. This study suggests a LOD-based Korean history contents implementation system, providing rich information environment by way of multi-dimensional web-data connections. In doing so, this system has tried a historic information circulation service system which is based on information sharing and connecting.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.287-297
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• 2010

Authentication is needed to use safe devices in the home network environment. In this authentication, there are an ID base form and Certification base form. In case of an ID base form, it is difficult to apply to the multi domain environment and in case of an Certification base form, because the way that contains and stores the certificate demand on devices, additional setting of the user is needed for transfer of ownership and purchase of new devices, and more. Because both ways attend an individual authentication for devices, the ways exist overhead as the frequent authentication for a lot of devices in service aspects of user needs. To arrange these problems, in this paper, the authentication information of devices can be securely stored and managed in the java card and a processing time of the authentication could be improved better then the existing technique by authenticating a group of service.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.419-425
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• 2009

The amount of incoming e-mails is increasing rapidly due to the wide usage of Internet. Therefore, it is more required to classify incoming e-mails efficiently and accurately. Currently, the e-mail classification techniques are focused on two way classification to filter spam mails from normal ones based mainly on Bayesian and Rule. The clustering method has been used for the multi-way classification of e-mails. But it has a disadvantage of low accuracy of classification and no category labels. The classification methods have a disadvantage of training and setting of category labels by user. In this paper, we propose a novel multi-way e-mail hierarchy classification method that uses PCA for automatic category generation and dynamic category hierarchy for high accuracy of classification. It classifies a huge amount of incoming e-mails automatically, efficiently, and accurately.

• International Journal of Highway Engineering
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• v.18 no.3
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• pp.47-57
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• 2016

PURPOSES : This study aims to examine the differences between the existing traffic demand forecasting method and the traffic demand forecasting method considering future regional development plans and new road construction and expansion plans using a four-step traffic demand forecast for a more objective and sophisticated national highway maintenance. This study ultimately aims to present future pavement deterioration and budget forecasting planning based on the examination. METHODS : This study used the latest data offered by the Korea Transport Data Base (KTDB) as the basic data for demand forecast. The analysis scope was set using the Daejeon Metropolitan City's O/D and network data. This study used a traffic demand program called TransCad, and performed a traffic assignment by vehicle type through the application of a user equilibrium-based multi-class assignment technique. This study forecasted future traffic demand by verifying whether or not a realistic traffic pattern was expressed similarly by undertaking a calibration process. This study performed a life cycle cost analysis based on traffic using the forecasted future demand or existing past pattern, or by assuming the constant traffic demand. The maintenance criteria were decided according to equivalent single axle loads (ESAL). The maintenance period in the concerned section was calculated in this study. This study also computed the maintenance costs using a construction method by applying the maintenance criteria considering the ESAL. The road user costs were calculated by using the user cost calculation logic applied to the Korean Pavement Management System, which is the existing study outcome. RESULTS : This study ascertained that the increase and decrease of traffic occurred in the concerned section according to the future development plans. Furthermore, there were differences from demand forecasting that did not consider the development plans. Realistic and accurate demand forecasting supported an optimized decision making that efficiently assigns maintenance costs, and can be used as very important basic information for maintenance decision making. CONCLUSIONS : Therefore, decision making for a more efficient and sophisticated road management than the method assuming future traffic can be expected to be the same as the existing pattern or steady traffic demand. The reflection of a reliable forecasting of the future traffic demand to life cycle cost analysis (LCCA) can be a very vital factor because many studies are generally performed without considering the future traffic demand or with an analysis through setting a scenario upon LCCA within a pavement management system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.181-185
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• 2016

In this paper we propose a VR-based Sailor Training Platform Authoring Tool which efficiently trains sailors in immersive ways. Proposed authoring tool consists of virtual environment reconstruction that imports real ship indoor environment into virtual environment and script editing which is able to implement various scenarios in emergency based on just drag-and-drop interface. The aim of importing real ship environment and supporting various VR devices is to enhance immersiveness and training so that trainees can deal with serious emergency events. Also the usefulness of the interface enables to reduce the cost of making training materials. Throughout scenario editing interface, the proposed authoring tool supports the editing of multi-user scenario and setting individual task for the evaluation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3C
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• pp.224-231
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• 2003

In this paper we proposed system parameter values of ultra-wideband Impulse Radio systems for the frequency band(3.1~10.6GHz), which is allocated by Federal Communications Commission(FCC). We also analyzed performance of the proposed system in the multiple access interference environment. According to result, application of possible pulse duration($t_{n}$) is very limited by 0.04~0.0326 ns in permission frequency range that establish in FCC. In the case of the same pulse signal power, we could know that system performance was changed by pulse repetition number($N_{s}$ ) regardless of pulse duration. Thus, We could know that we have to need duration of monocycle pulse and setting of frame un it time(Τ$_{f}$ ) according to multi user numbers and design proper pulse repetition number by transfer rate in multiple access systems design. In the IR system that needs high speed transmission more than 50 Mbps in multiple access interference environment, we could know that very serious performance decrease by multiple access interference happens. Therefore, as the design of high speed multiple access IR system, it should be designed to additional improvement techniques that can remove multiple access interference at the same time.