• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.814-827
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• 2004

The compressed mode is used to perform inter-frequency and inter-system handover in WCDMA. The instantaneous transmit power is increased in the compressed frame in order to keep the QoS(Quality of Service) unaffected by the reduced processing gain. Furthermore, since the inner loop power control is not active during the transmission gap and the effect of interleaving is decreased, a higher Eb/No target is required, which directly affects the system performance. Due to the impact on performance, the compressed mode should be activated by the RNC(Radio Network Controller) only when there is real need to execute an inter-frequency or inter-system handover. However, 3GPP does not define the method that decides the compressed mode activation. In order to reduce performance degradation, there is need the decision method. In this paper, we consider a combined cell structure in which some neighbor cells have a frequency the same as serving cell and the others have a different frequency or system. Under consideration, we analyze the effect of the compressed mode on the WCDMA forward link performance. In order to avoid performance degradation, we propose an UE(User Equipment) measurement method that can restrict the activation area of the compressed mode of UE that does not need it and evaluate its performance by simulations. Analytical results show that the use of the compressed mode affects the performance degradation. And simulation results show that proposed method leads to better performance.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.13-16
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• 2000

This paper introduces a more effective usage of the limited OVSF cod in compressed mode which is used during inter-frequency/inter-system handover in UTRA(Universal mobile telecommunications system) Terrestrial Radio Access). The usager is to use dynamic common channel which is shared by several users during the compressed mode.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.102-108
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• 1991

Utilizing self-phase modulation effects of a dispersion-shifted fiber and delay-line characteristics of two gratings, mode-locked 80 ps pulses at 1.319${\mu}{\textrm}{m}$ wavelength from a Nd: YAG laser are compressed down to 2.1 ps. These pulses are further compressed down to 340 fs using higher order soliton effects in a common single mode fiber.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.451-460
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• 2004

The pilot bit pattern of W-CDMA system is used for the channel estimation and frame synchronization confirmation. This paper proposes the binary sequences for the frame synchronization for wideband code division multiple access (W-CDMA) system. We present the circuit for the generation of ideal frame synchronization property using the binary sequences called frame synchronization word(FSW). W-CDMA system uses compressed mode where up to 7 slots per one 10 msec frame are not transmitted to make measurements from another frequency without a full dual receiver terminal. It is shown that the proposed frame synchronization words also maintain the optimal frame synchronization property in the compressed mode by using the complementary mapping relationship of preferred pair. And we discuss the realization circuit for the generation of frame synchronization words by using the concept of preferred pairs, complementary mapping relationship, and maximal length sequence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.106
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• pp.272-279
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• 2006

In this paper, we evaluate the performance of frame synchronization words of pilot bit patterns which are used for the channel estimation and frame synchronization confirmation in W-CDMA(Wide band Code Division Multiple Access) system. W-CDMA system also uses compressed mode to make measurements from another frequency without a full dual receiver terminal. It is confirmed by using computer simulation that the proposed frame synchronization words also maintain the frame synchronization property in the compressed mode by using the complementary mapping relationship of preferred pair ROC(Receiver Operating Characteristic) curves with probability of detection and false alarm are used to analized the performance of the proposed frame synchronization words by using the various detection metrics such as LLRT(Log Likelyhood Ratio Test), GLRT(Generalied Likelyhood Ratio Test), soft and hard correlation tests in AWGN and Rayleigh fading channels. It is expected that the research results fer the performance of pilot bit patterns of this paper can be useful reference for the design and implementation of frame synchronization in 3rd generation W-CDMA system.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.50-56
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• 2011

A preliminary experimental study of new concept air hybrid engine, which stores compressed air in the tank during braking and re-use it to propel vehicle during crusing or acceleration, was carried out in this study. A single cylinder engine was modified to realize the concept of air hybrid engine. Independent variable valve lift system was adopted in one of the exhaust valves to store the compressed air into the air tank during compression period. An air injector module was installed in the place of spark plug, and the stored compressed air was supplied during the expansion period to realize air motoring mode. For air compression mode, the tank with volume of 30 liter could be charged up to more than 13 bar. By utilizing this stored compressed air, motoring work of 0.41 bar of IMEP(Indicated mean effective pressure) at maximum can be generated at the 800rpm conditions, which is higher than the case of normal idle condition by 1.1 bar of IMEP.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.969-974
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• 2001

Circular cylindrical tubes are widely used in structures such as vehicles and aircraft structures, where light weight and high compressive/bending/torsional load carrying capacity are required. When axially compressed, relatively thick circular cylindrical tubes deform in a so-called ring mode. Each ring develops and completely collapses one by one until the entire length of the tube collapses. During the collapse process the tube absorbs a large amount of energy. Like honey-comb structures, circular cylindrical tubes are light weighted, are capable of high axial compressive load, and absorb a large amount of energy before being completely collapsed. In this report, the subject of axial plastic buckling of circular cylindrical tubes was reviewed first. Then, the axial collapse process of the tubes in a so-called ring mode was studied both experimentally and numerically. In the experiment, steel tubes were axially compressed slowly until they were completely collapsed. Fixed boundary condition was provided. Numerical study involves axisymmetric, elastic-plastic, large deflection, self-contact mechanisms. The measured and calculated results were presented and compared with each other. The purpose of the study was to evaluate the load carrying capacity and the energy absorbing capacity of the tube.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.600-602
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• 1998

RFC 959 정의한 FTP 의 세가진 전송모드, Stream, Block, Compressed전송 모드 중 현재 주로 사용되고 있는 전송 모드는 Stream 전송모드인데. 이 Stream전송모드에서 서버 또는 네트웍에 치명？인 오류 발생하였을 경우 이를 체크 할 수 없고 서버에 재접속하였을 겨우 처음부터 재전송 하영햐 하는 문제점이 발생한다. 이를 개선한 Block, Compressed전송 모드의 경우, 데이터 스트림에 정보 헤더를 추가하여야 함으로써 오버 헤드를 발생한다. 본 논문에서는 클라이언트 FTP상에서 전송 상태를 체크하게 함으로서 전송 중단시 중단된 시점부터 나머지 데이터를 보냄으로써 FTP의 스트림 전송 모드의 문제점을 개선하는 방법을 제시한다.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.21-24
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• 2000

In this paper, We introduce effective handoff method from W-COMA system of 3$^{rd}$ generation to 15-95 system of 2$^{nd}$ generation. In case of this handoff, Ms should know long code state using traffic channel, timing information and pilot offset of 26 synchronous system during the compressed mode. So We establish additional common channel in order to obtain handoff information. Common channel transmits same information from all base stations and provides MS with timing information of zero offset. long code state and timing of super frame for sync. channel. Therefore during the compressed mode. MS can obtain information for handoff using common channel..

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.1
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• pp.53-59
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• 2000

Recently air pollution is increased according to increase of vehicle. So many countries are studying about compressed natural gas engine. Research on the development of CNG dedicated engine that has important meaning both as a clean fuel and an alterna-tive energy to reduce the exhaust emission from diesel engine are actively going on these days. In this study the character-istics of CNG engine was investigated and the engine performance experimented by changing the parameters such as boost pressure. The CNG engine performance and exhaust emission were measured by engine performance mode at maximum load condition with increasing the rpm in the range of 1,000-2,200rpm. The exhaust emission was also measured at D-13 mode and compared to the emission regulation.