• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.474-480
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• 2001

In this paper a low signal reduction communication system that does not use the communication line but power line is presented It will be very useful for an information-oriented society with tele-metering and home automation. The conventional system has a difficulty in transmitting information due to decreasing communication voltage. The proposed system employs a special type switching amplifier system which has a low inner resistance and uses high efficient ferrite core in coupling circuit. This new system is proposed to reduce the loss of conductor load and coupling circuit in a PLC system.

• MALSORI
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• no.67
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• pp.79-102
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• 2008

In this paper, we investigate the relation between Bayes factor and likelihood ratio test (LRT) approaches and apply the neighborhood information of Bayes factor to building an alternate hypothesis model of the LRT system. To consider the neighborhood approaches, we contemplate a distance measure between models and algorithms to be applied. We also evaluate several methods to improve performance of utterance verification using neighborhood information. Among these methods, the system which adopts anti-models built by collecting mixtures of neighborhood models obtains maximum error rate reduction of 17% compared to the baseline, linear and weighted combination of neighborhood models.

• The KSFM Journal of Fluid Machinery
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• v.19 no.6
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• pp.19-25
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• 2016

Anti-icing is important in gas turbines because ice formation on compressor inlet components, especially inlet guide vane, can cause performance degradation and mechanical damages. In general, the compressor bleeding anti-icing system that supplies hot air extracted from the compressor discharge to the engine intake has been used. However, this scheme causes considerable performance drop of gas turbines. A new method is proposed in this study for the anti-icing in combined cycle power plants(CCPP). It is a heat exchange heating method, which utilizes heat sources from the heat recovery steam generator(HRSG). We selected several options for the heat sources such as steam, hot water and exhaust gas. Performance reductions of the CCPP by the various options as well as the usual compressor bleeding method were comparatively analyzed. The results show that the heat exchange heating system would cause a lower performance decrease than the compressor bleeding anti-icing system. Especially, the option of using low pressure hot water is expected to provide the lowest performance reduction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.725-731
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• 2003

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-.oiling system (MD-ARS) might be one candidate of several systems against the ship's rolling. As the movable range of the mass on the ship is finite, the control system must include restriction on the mass position to protect the device and the ship. This restriction usually causes windup phenomenon and control performance is deteriorated seriously. We adopt anti-windup technique to improve the control performance and demonstrate its efficiency by simulation.

• Journal of Korea Trade
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• v.24 no.3
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• pp.1-19
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• 2020

Purpose - This study empirically analyzes the effects of provisional anti-dumping duties levied on imports by Korea following anti-dumping investigations. An anti-dumping duty is a legal tool that countries use to impose duties on imports to offset injurious dumping. This study verifies how effective the imposition of a provisional anti-dumping duty is and whether such duties have trade chilling effects on aggregate imports. Specifically, this study examines import trade diversion from named to unnamed countries caused by the imposition of provisional anti-dumping duties. Design/methodology - This empirical analysis employs an econometric model of provisional anti-dumping measures for cases in which Korea imposed final affirmative anti-dumping measures. We construct a monthly panel dataset for each stage of anti-dumping investigation undertaken by Korea for all manufacturing industries during 1995-2013. We illustrate a stage-by-stage analysis of anti-dumping investigations from initiation, preliminary decision, imposition of provisional duty, final affirmative decision, and imposition of final affirmative duty on a monthly basis at the six-digit harmonized system code-level. Findings - For cases in which provisional duties are imposed, the reduction in imports from named countries outweighs the increase in imports from unnamed countries. The substantial reduction in imports from named countries is large enough to offset the import diversion to unnamed countries, suggesting that import diversion in investigations is limited during the investigation period. Therefore, the use of provisional anti-dumping duties in Korea is effective, providing evidence of a chilling effect on aggregate imports. Originality/value - Few studies examine the size of the effects on import trade diversion of the imposition of provisional anti-dumping duties. We contribute to the literature by disentangling separate trade effects for each phase of the anti-dumping investigation process and imposition of provisional duty.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.438-441
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• 2004

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MD-ARS) might be one candidate of several systems against the ship's rolling. In this paper, a sea-trial test on a pendulum-type MD-ARS passively operated is carried out in Suyoung, Busan. After the system is installed on the cabin of the small leisure boat, a series of test is conducted before and after operating the system. Through the test, it is confirmed that the roll rate of the ship is pretty well reduced by the system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.875-879
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• 2006

Noise reduction has become a major issue of the duct air-conditioners. This paper describes the reduction of noise and vibration of rotational slim duct system. The design of slim duct system is the most important point of noise reduction in terms of the motor of 2f line noise, resonance noise between forced frequency and natural frequency of Sirocco fan, unbalance noise of motor axis and the noise induced refrigerant. The noise of duct system is mainly measured from diffuser and bottom of duct. The optimal design was implemented after measuring the effect of noise and vibration in each part which is composed of duct system. In this paper, experimental results show that the main elements in air-conditioner duct design. These elements are anti-vibration rubber of motor, axis length of motor, rubber coupler, materials of sirocco fan and control method of motor which are the most vital factors in reducing noise.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.20-26
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• 1997

A System for reducing vehicle body roll by active control is developed. The stabilizer bar with hydraulic rotary actuator produces anti-roll moment which suppresses roll tendency. This reduction of roll improves the driving safety as well as the ride comfort. Vehicle test data shows considerable reduction of roll angle during steady-state turning. Also improvement of ride comfort is achieved by making the actuator freely rotatable, i.e. by connecting all chambers of actuator in normal driving conditions. A control algorithm using steering wheel angle and vehicle speed signal as input valve is applied. It is compared with signal of the G-sensor.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.1
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• pp.1-10
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• 2008

In order to evaluate performance of anti-vibration gloves, it is necessary to measure the transmitted vibration to the hand and the applied forces at the same time while gripping the vibrating handle. In the study a system was developed to measure both the vibration and the forces. The system consists of a measurement handle with eight strain gauges and two accelerometers and a PC-based system with a software for signal processing, evaluation of the hand-transmitted vibration and for control of applied forces in the pre-determined range. The handle was installed on the vibration shaker which is strong enough so as not to be affected by dynamic coupling with the hand-arm. Whole procedure of ISO 10819:1996 to determine the vibration transmissibility of anti-vibration gloves was programmed into the system. As an example of the application, three subjects joined the test to get vibration transmissibilities of 9 anti-vibration gloves where each glove was tested twice a subject. Average and standard deviation of the corrected vibration transmissibility were also calculated. All tested gloves fulfilled criterion for M-spectrum($\overline{TR_M}$<1.0), but one glove fulfilled criterion for H-spectrum($\overline{TR_H}$<6.0),

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.566-574
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• 2005

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MO-ARS) might be one candidate of several systems against the ship's rolling. As the movable range of the mass on the ship is finite, the control system must include restriction on the mass position to protect the device and the ship. This restriction usually causes windup phenomenon and control performance is deteriorated seriously. Two control algorithms, anti-windup control and saturated sliding mode control, are studied in this paper. Control performance and robustness problem are checked out by numerical simulations.