• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.7 s.238
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• pp.1035-1041
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• 2005

Dynamic characteristics of CD/DVD deck fur vehicle are analyzed in this paper. Generally CD/DVD deck for vehicle is used from inferior environment with the vibration of the vehicle, shock of outside and so on. Therefore it must have the structure which is stabilized from the vibration to prevent read error. For this purpose, vibration characteristic of the deck for vehicle should be identified. To analyze characteristic of the deck system, we perform the signal analysis and modal testing using the EFT analyzer. Also we change the design factor degrading the performance of the deck system and verify the efficiency improvement using the acceleration measurement occurring to the sound discontinuation.

• Journal of Korea Multimedia Society
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• v.3 no.6
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• pp.643-651
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• 2000

ATM network technology is generally used for the integration of multimedia services in high-speed Internet. ABR (Available Bit Rate) and UBR (Unspecified Bit Rate) service classes have been developed specifically to support data application. In this paper, through the result of simulation, we analyzed the effect of TCP data transmission performance by using FRR (Fast Retransmission and Recovery) and Nagle's Algorithm on the UBR service, and by adjusting EFCI switch parameter on the ABR service. As a result of our study, performance improvement of TCP over ATM network is observed by adjusting TCP parameters and setting of effective switch parameter.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.174-183
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• 2004

In this paper, the performance improvement and modeling of small onboard generator were described. As the characteristics of the field coil which are a major parameters of generator were improved, the system bandwidth could be increased, therefore the generator could also be satisfied with fast characteristic loads. Established the brief control model of the generator, it could be possible to do the analysis of generator performance, and improve the operational stability of the generator system using the control model.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1929-1932
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• 2002

In this paper, some parameters are studied for the performance improvement of a bulk optical current sensor. The performance of optical current sensor is influenced by current measuring range, Verdet constant change due to temperature change, temperature variation of wave plate, signal to noise ratio of optical transmitter/receiver, optical bias mismatch. Two types of optical current sensors are implemented and tested in the current range from 10 ampere to 200 ampere.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.819-824
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• 2005

Recently, micro hydropower attracts attention because of its clean, renewable and abundant energy resources to develop. However, suitable turbine type is not normalized yet in the range of micro hydropower and it is necessary to study for the effective turbine type. Moreover, relatively high manufacturing cost by the complex structure of the turbine is the highest barrier for developing the micro hydropower turbine. Therefore, a cross-flow turbine is proposed for micro-hydropower in this study because of its simple structure and high possibility of applying to low head. The purpose of this study is to further simplify the turbine structure and improve the performance, A guide vane is removed and the runner chamber is made compact using a new air supply method. The results show that the efficiency of the turbine is improved in a wide operating range and the size of the turbine is remarkably reduced.

• Biomolecules & Therapeutics
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• v.20 no.5
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• pp.446-456
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• 2012

Actoprotectors are preparations that enhance body stability against physical loads without increasing oxygen consumption or heat production. Or, in short, actoprotectors are synthetic adaptogens with a significant capacity to improve physical performance. This paper explores the history of actoprotectors' development, their pharmacological properties, mechanism of action, and practical application to the improvement of mental and physical performance. A brief summary of the clinico-pharmacological characteristics of the main representatives of this class (bemitil and bromantane) is provided. Some other synthesized compounds, and even natural ones such as ginseng, also are regarded as potential actoprotectors, and these are treated herein as well. Actoprotectors, owing to their wide-ranging pharmacological activities, high efficiency and safety, can be applied under either normal or extreme conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.255-256
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• 2006

This paper presents the performance improvement of a Nozzle/Ball type servovalve with variant drain orifice. First of all, the configuration of the novel servovalve is proposed. Then, the static characteristics are investigated under blocked load condition, and its dynamic characteristics are analyzed by using the linearized flow-pressure relationship. Finally, the performance at the null condition of the proposed servovalve is numerically evaluated through the comparison study with the convention at counterparts.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.9 s.102
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• pp.1060-1069
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• 2005

Silencers are engineering devices that are designed to attenuate sound waves propagating in a flowing medium. The muffler type silencer has a series of chambers in parallel or series utilizing the reflection and expansion characteristics of the expansion chambers, sidetubes, branch resonators, and tailpipes to attenuate the sound. To Improve the performance of industrial blower silencer of muffler type which is employed in petrochemical plant, this paper seeks its optimal arrangement of buffs by experimental method and suggests optimal arrangement of buffs. Experimental results show that the optimal one suggested can reduce the noise level as much as 14 dB (or 18 dB(A)) in the laboratory and as much as 4 dB(A) compared to that of the existing silencer on the ground.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.3
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• pp.222-226
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• 2005

A series of model tests carried out at the CWC of WJFEL for the purpose of prediction of resistance for the performance and improvement of resistance by attaching appendage for the ship of 50 knots class planing hull. The resistance performance evaluation has been carried out for the bare hull and for the appendage hull with two different depth of vertical type wedges. In the bare model test, trim and sinkage is calculated for the planing hull and the resistance is calculated. For minimizing the resistance, wedge appendage is attached and tested. Analysis and tests shows that for a 12.5mm wedge, resistance is minimum and overall power tallied to 5636ps.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.151-159
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• 1998

The heavy equipment such as tracter has been studied to improve rather the performance of engine than comfort. The mufflers of tracters have various specifications according to their uses. The exact analysis of various mufflers is needed to reduce the level of exhaust moise, a major noise source of engine, to improve the ride quality of tracter. In this study, a software based on Green's function is developed to predict the performance of sound transmission loss for a muffler according to the locations of inlet/outlet pipes. The locations of inlet and outlet pipes can be fixed at different position individually. The conventional muffler has the locations of inlet/outlet pipes on the direction of longitudinal axes. On other hand, the inlet and outlet pipes may be located at the circumferential surface of a test muffler such as one of tracter. The software is verified by analysis and experiment on current muffler of tracter and the improvement technique is proposed to reduce the level of exhaust noise.