• Journal of Communications and Networks
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• v.15 no.2
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• pp.191-197
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• 2013

In this paper, a mobile relay station (MRS) for vehicles with a beamforming antenna is considered to increase the reliability of the transmission link, particularly for the MRS at the cell boundary. A cell searching and direction-of-arrival estimation method for an MRS with a uniform linear array is proposed for OFDM-based cellular systems in a multipath environment, even with the existence of the symbol timing offsets and carrier frequency offsets. The performance of the proposed method is evaluated by computer simulation using the standard profile of IEEE 802.16e.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06b
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• pp.121-127
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• 1999

본 논문에서는 디지털 방송의 시대를 맞아 새롭고 다양한 정보 서비스를 가능하게 할 디지털 데이터방송을 위해서 국내 환경에 적합한 데이터방송 프로파일을 제안하고 그 내용을 소개한다. 여기서 프로파일이라는 것은 표준(standard)과는 달리 서비스 어플리케이션 및 송 ·수신 시스템을 포함하여 실제로 데이터방송을 서비스하기 위해서 규정한 방송구현 단계의 구체적 규격이다. 데이터방송의 가능한 서비스 형태로는 TV 프로그램 자체를 소개하는 프로그램 안내정보 서비스, 방송중인 TV 프로그램 관련 정보를 서비스하기 위한 TV 프로그램 연관 데이터 서비스, TV 프로그램 내용과 독립적으로 멀티미디어 정보를 제공하기 위한 순수 데이터 서비스, 그리고 방송국과 양방향 네트워크로 연결하여 제공되는 양방향 서비스가 있다 이러한 서비스를 개발하기 위해서는 국내 환경에 적합한 데이터방송 프로파일이 필요하며 그 일환으로 현재 MHEG-5를 이용하여 데이터방송이 가능하도록 프로파일을 구성해 나가고 있다 그리고 MHEG-5 프로파일을 이용한 서비스 어플리케이션을 제작하여 디지털 위성방송 시스템에 적용하였다 데이터방송의 규격은 국제적으로 아직 많은 부분에 있어서 유동적이므로 이 연구를 바탕으로 향후 지속적으로 국제적 흐름을 분석하여 국내 환경에 적합하도록 프로파일을 개선해 나갈 것이다.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.854-859
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• 2002

Location Based Services, or LBS refers to value-added service by processing information utilizing mobile user location. With the rapidly increasing wireless internet subscribers and world LBS market, the various location based applications are introduced such as buddy finder, proximity and security services. As the killer application of the wireless internet, the LBS has preconsidered technology about location determination technology, LBS middleware server for various application, and diverse contents processing technology. This paper describes the open architecture for LBS platform ensuring interoperability among the wireless networks and various location-based application services and the functional requirements for the LBS platform. The LBS platform in a narrow sense provides a standard interfaces for location management and network management for location services as follows, positioning (location acquisition through network or/and handset), location managing, location based functions, profile management, authentication and security, location based billing, information roaming between carriers and the system monitoring independent to specific network or ISP/CPs(Content Providers).

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.3
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• pp.1-9
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• 2009

Noise reduction for hydraulic pump is strongly demanded in the market with its efficiency and durability. In order to meet this demand, it is necessary to reveal mechanism for noise and relationship between the important factors. In this paper, mathematical model for cylinder pressure which is primary reason of pulsation and sound noise were established, and examined its pressure profile by simulation. Also, the valve plate of three kind types are manufactured and tested for piston pressure, pressure pulsation, and sound power level based on the tentative standard which is officially recognized.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1132-1137
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• 2008

Automatic Operation based on ATO (Automatic Train Operation) is necessary for driverless Light Rail Transit business. When this kind of driverless LRT operation plan is made, TPS (Train Performance Simulation) is traditionally simulated at all-out mode and coasting mode based on manual operation. Commercial schedule speed equals to all-out speed minus $9{\sim}15%$ make-up margin. Coasting mode TPS simulation is also run at commercial schedule speed to calculate run time and energy consumption. But TPS based on manual operation should make an improvement on accuracy in case of driverless LRT operation Plan. In this paper, new fast mode TPS simulation using ATO pattern is proposed and show near actual ATO result. The actual ATO pattern can be accurately simulated with the introduction of 4 parameters such as commercial braking rate, jerk, station stop profile and grade converted distance. Normal mode TPS simulation for commercial schedule speed can be designed to have fast mode trip time plus 3 seconds/km margin recommended by korean standard LRT specification.

• Advances in aircraft and spacecraft science
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• v.6 no.4
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• pp.283-296
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• 2019

The influence of different planform parameters on the aerodynamic performance of large-scale subsonic and transonic Blended Wing Body (BWB) aircraft have gained comprehensive research in the recent years, however, it is not the case for small-size low subsonic speed Unmanned Aerial Vehicles (UAVs). The present work numerically investigates aerodynamics governing four different trailing edge geometries characterizing BWB configurations in standard flight conditions at angles of attack from $-4^{\circ}$ to $22^{\circ}$ to provide generic information that can be essential for making well-informed decisions during BWB UAV conceptual design phase. Simulation results are discussed and comparatively analyzed with useful implications for formulation of proper mission profile specific to every BWB configuration.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.244.1-244.1
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• 2003

We aimed at determining bioavailability of clonazepam, an anxiolytic drug, and developing a simple analysis in human blood using HPLC. A rapid and sensitive HPLC method was developed and validated using reverse-phase C18 column with retension time and limit of quantification of clonazepam being 2.58 min and 5hg/ml, respectively. Quantification was performed at 235 nm with p-hydroxybenzoic acid ethyl ester as internal standard. The method involved a simple extraction. In order to study blood level profile in time, sight volunteers were enrolled and orally took 6 mg clonazepam once. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.240.2-240.2
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• 2003

We aimed at determining bioavailability of procainarnide HCl, an antiarrhythmic drug, and developing a simple analysis in human blood using HPLC. A rapid and sensitive HPLC method was developed and validated using reverse-phase C18 column with retension time and limit of quantification of procainamide HCl being 2.58 min and 50ng/ml, respectively. Quantification was performed at 275 nm with caffeine as internal standard. The method involved a simple extraction. In order to study blood level profile in time, eight volunteers were enrolled and orally took 250 mg procainamide HCl once. (omitted)

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.609-615
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• 2012

TPS (Train Performance Simulation) based on ATO (Automatic Train Operation) is required for driverless LRT (Light Rail Transit) operation plan instead of typical TPS based on driver operation. In this paper, new TPS model using ATO pattern is proposed and compared with the automatic train operation result in a test line of Seoul Metro Line 6 and in a whole line of Busan-Gimhae LRT. The actual ATO pattern can be very accurately simulated by new TPS model with the introduction of 4 parameters such as commercial braking rate, jerk, station stop profile and grade converted distance. The commercial scheduled time for driverless automatic train operation can be proposed to have "Fast" mode TPS trip time plus 3 seconds/km margin recommended by Korean standard LRT specification in this paper.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.6 s.312
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• pp.97-104
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• 2006

The state-of-the-art H.264/AVC standard was designed for the lossy video coding so that it could not yield the best performance for lossless video coding. In this paper, we propose two efficient intra lossless coding methods by embedding a pixel-wise prediction into the H.264/AVC. One is based on the pixel-wise prediction for the residual signal of the H.264/AVC intra Prediction and the other suggests a newly additional intra prediction mode for the conventional intra prediction. We found that the proposed lossless coding algorithms could achieve approximately $12%{\sim}25%$ more bit saving compared to the H.264/AVC FRExt high profile for several test sequences in terms of a compression ratio.