• ETRI Journal
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• v.35 no.6
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• pp.960-968
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• 2013

To implement a cloud game service platform supporting multiple users and devices based on real-time streaming, there are many technical needs, including game screen and sound capturing, audio/video encoding in real time created by a high-performance server-generated game screen, and real-time streaming to client devices, such as low-cost PCs, smart devices, and set-top boxes. We therefore present a game service platform for the running and management of the game screen, as well as running the sound on the server, in which the captured and encoded game screen and sound separately provide client devices through real-time streaming. The proposed platform offers Web-based services that allow game play on smaller end devices without requiring the games to be installed locally.

• Information and Communications Magazine
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• v.28 no.10
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• pp.3-10
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• 2011

The increasing ubiquity of wireless networks and decreasing cost of hardware is fueling a proliferation of mobile devices. These devices are enabling a new revolution in mobile technology, not only running locally on them, but running on cloud as a service as well. From web browsing, email, or video conferencing, presentations to movie and music entertainment or games, multimedia applications, mobile cloud enables providing such diverse applications. Many technologies have been designed to address the limited hardware and performance in thin client PC. However, with the assorted network and graphic condition, those proposed technologies is obligated to alter aim to adapt mobile cloud. In this paper, we provide a survey of client technology on a Server that can be sufficed the requirements of Mobile Cloud. We also analyze each technology and classify with its individual difficulties and challenges.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.135-142
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• 2007

The service running of driverless rail vehicle has been required by various social and commercial issue. Currently, the new domestic line between Bu-san and Gim-hae is plan to be provided the LRV(Light Rail Vehicle) with driverless operation firstly in domestic service. These driverless vehicle have some major properties to make it lower the operating and maintenance cost, however on the other side, it unavoidably raise some potential hazard to make it lower the passenger safety because it is hard to take care immediately in emergency state during vehicle running. Therefore it is highly requested that we should consider various conditions at design stage to manufacture and operate the safest vehicle. Therefore, in this paper, we will survey the design concept of vehicle interior facilities based on the previous experience, (1) The difference of interior facilities between normal and driverless vehicle, (2) design and operational concept of passenger side door function to find out best application for domestic line driverless vehicle.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.71-77
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• 2007

The surface of railway wheel tread in wheel-rail system can not be free from wear because of various circumstance such as railway condition, maintenance condition, weather condition, characteristics of wheel surface's geometrical shape, and vehicle suspension's structural characteristics etc. Therefore, the research on wear reduction and maintenance method are very important to ensure the safety of railway vehicle, to improve car comfort and to decrease maintenance cost. In this study, the wear rates of railway wheel have been periodically measured in terms of the running distance of Electrical Multiple Unit which have been currently operated and the microstructure transformation of wheel tread using replication method have been performed. The results show that the relations between the flange wear and tread microstructure are depended on running distance and it will supply basic data on wheel maintenance.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2156-2162
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• 2008

To reduce the cost and the time of transport in Eurasian railroad networks such as TKR, TCR and TSR owing to the problem of different track gauges (narrow/standard/broad gauge), it is important to develop the gauge - adjustable wheelset system to adapt easily to these gauges. The gauge - adjustable wheelset system in the transcontinental railway have been proposed as a more effective way in comparison with other techniques for overcoming difference in track gauges. Assume that the freight train with gauge adjustable wheelset system is running from domestic train network to TCR, TSR in Eurasian continent, it is necessary to estimate the safety of this system. This study is evaluated at examination of safety for freight train with gauge adjustable wheelset system by simulated durability analysis. Moreover, the predicted fatigue life at running track using the durability simulator was verified by the durability test according to UIC standard.

• YAKHAK HOEJI
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• v.41 no.5
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• pp.539-546
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• 1997

Capillary electrophoresis (CE) is perceived as an attractive tool for the analysis of pharmaceuticals and biological materials because of their high separation efficiency, easy separation and low running cost. New concept of micellar electrokinetic capillary chromatography (MECC) expanded the application of CE to the separation of neutral molecules. Validation of CE as an analytical technique for quality control of pharmaceuticals should be confirmed by quantitative analysis and the peak confirmation. In this study, the quantitative analyses of various types of neutral, acidic and basic components (acetaminophen, caffeine, ascorbic acid, riboflavin, thiamine, chlorpheniramine, phenylpropanolamine, dl-methylephedrine and dextromethorphan) in complex cold medicines have been accomplished using CE. Combined methods of MECC using SDS and capillary zone electrophoresis lowering the pH of running buffer were adopted to determine the ingredients in capsule type or liquid formula complex medicines without particular sample pretreatment. The results indicate that CE is a promising technique for quality control analysis of pharmaceuticals as a validation method.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.805-810
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• 2005

The main functions of suspension system of railway vehicle are isolating vibration from track irregularity to car-body for the Ride quality and keeping its stability with limitation of vehicle's movement. These two functions conflict with each other, then it is impossible to achieve both of performance with traditional passive suspension which has constant characteristics. So, to improve this situation the active suspension was suggested and in specially the semi-active suspension is noticed for its effectiveness on cost despite of its lower performance than full-active suspension. In this study the control logic made through LQG theory was designed with simplified vehicle model and variable damper model defined by $1^{st}$ order system, then the analysis of simulation results was done to understand influence on the performance of semi-active suspension with running conditions and response characteristics of variable damper.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.344-346
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• 1998

The OBCS(On-Board Computer System) achieves train system diagnosis and control. For commercial train operation, it must guarantee the reliability for safe and have low cost operational algorithm. To guarantee the diagnosis function and the control ability of OBCS, sufficient actual railway running test under severe conditions is required. But, running test has some limitations for making severe conditions because of safety and it demands quite long time and a lot of costs. So simulator is required and is utilized in many countries. We designed a simulator to test various functions and performance of controllers for high speed train's power car under various conditions and it is represented briefly.

• Journal of the Korean Operations Research and Management Science Society
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• v.4 no.1
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• pp.51-67
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• 1979

This paper considers the problem of determining an optimal dynamic operating policy for a two-stage tandem queueing service system in which the service facilities (or stages) can be operated at more than one service rate. At each period of the system's operation, the system manager must specify which of the available service rates is to be employed at each stage. The cost structure includes an operating cost for running each stage and a service facility profit earned when a service completion occurs at Stage 2. We assume that the system has a finite waiting capacity in front of each station and each customer requires two services which must be done in sequence, that is, customers must pass through Stage 1 and Stage 2 in that order. Processing must be in the order of arrival at each station. The objective is to minimize the total discounted expected cost in a two-stage tandem queueing service system, which we formulate as a Discrete-Time Markov Decision Process. We present analytical and numerical results that specify the form of the optimal dynamic operating policy for a two-stage tandem queueing service system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2626-2634
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• 1997

The purpose of multicasting is to reduce the network costs for transmitting the same traffic to multiple destinations. In this paper, an efficient delay-bounded multicasting routing algorithm is proposed, which satistifies the network conditions of cost minimization and can adjust the dynamic events, such as 'leave and/or join ones' from the multicast group. Also, our algorithm is designed for various network requirements such as the efficiet dynamic group support, high-quality data distribution, and adaptability to variable situation. After the delay tolerance and the maximum group size are determined according to network state and requirements for delay and cost, the dynamic delay-bounded multicast tree is constructed using partial multicast routing. We evaluate the performance of the proposed algorithm by running simulations on randomly generated test networks using a Sun Sparc 20 workstation. We were able to obtain good simulation resutls, which means solutions that lies between the minimum cost solution and the minimum delay one.