• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.5
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• pp.475-480
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• 2014

This study proposes a new synthetic test circuit (STC) for HVDC thyristor valve tests. The conventional STC with a 2-phase chopper requires a 3-phase transformer, a 3-phase diode rectifier, and an IGBT to facilitate the off state of an auxiliary thyristor. In the proposed STC, these three components are replaced with one diode and one resistor, which result in the simplified implementation of the hardware of the STC. Simulation and experimental results demonstrate the validity of the proposed scheme.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.245-246
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• 2018

This paper is a multipurpose functional synthetic resin formwork which can replace existing euro form. We tried to improve the disadvantages such as work noise, stenosis, recyclability, and workability of Euroform system. As a result of the test, Euroform showed an average of 106.7dB and synthetic resin formwork showed an average of 100.4dB. Therefore, it is considered that the synthetic resin formwork has a great effect of noise reduction compared to the euro form.

• YAKHAK HOEJI
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• v.47 no.1
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• pp.5-9
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• 2003

Synthetic aluminum silicate was prepared by reacting aluminum sulfate solution with Sodium silicate solution in this study. The optimum synthesis conditions based on the yield of the product were established by applying Box-Wilson experimental design. The results were found to be as follows; Reactant temperature : 50∼72$^{\circ}C$, Concentration of two reactants : 10∼17.6％, Mole ratio of two reactants, [Sod. silicate]/[Al. sulfate) : 4.6∼5.0, Temperature of washing water : 25∼4$0^{\circ}C$, and Drying temperature of product : 50∼$65^{\circ}C$. The physical and chemical properties of synthetic aluminum silicate as medicine were investigated by means of chemical analysis, adsorption test and acid consuming capacity measurements.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.43-50
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• 2009

In order to reduce the download around Smart UAV(SUAV) at hovering and transition mode, flow control using synthetic jet has been performed. Many of the complex tilt rotor flow features are captured including wing leading and trailing edge separation, and the large region of separated flow beneath the wing. First, in order to control the trailing edge separation, synthetic jet is located at 30, 95% of flap chord length. The flow control using synthetic jet on flap shows that stall characteristics depending on several mode can be improved through separation vortices resizing. Also, a flap jet and a 0.01c jet which control the separation efficiently are applied at the same time at each test case because controlling the leading edge separation is essential for download reduction. As a result, time averaged download is reduced about 18% comparing with no control case at hovering mode and 48% at transition mode. These research results show that if flow control using leading edge jet and trailing edge jet is used effectively to the SUAV in overall flight mode, flight performance and stability can be improved.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.101-106
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• 2005

It needs to accumulate a store of know-how on the design, precision processing and appraisement for metering pump which is a kind of gear pump fer synthetic fibers. But the period and cost fur development is not effective, because designers experience many trial and error for the pump design and manufacturing process. Therefore, in order to curtail the period and cut down expenses, the analysis and simulation system is required for a designed metering pump. In this study, the pump simulation software was developed with the visual C++ language and the image processing algorithm, and was investigated through a discharge test for the planetary gear type metering pump.

• Speech Sciences
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• v.15 no.4
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• pp.97-105
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• 2008

Nowadays an HMM-based text-to-speech system (HTS) has been very widely studied because it needs less memory and low computation complexity and is suitable for embedded systems in comparison with a corpus-based unit concatenation text-to-speech one. It also has the advantage that voice characteristics and the speaking rate of the synthetic speech can be converted easily by modifying HMM parameters appropriately. We implemented an HMM-based Korean text-to-speech system using a small size Korean speech DB and proposes a method to increase the naturalness of the synthetic speech by controlling duration model parameters in the HMM-based Korean text-to speech system. We performed a paired comparison test to verify that theses techniques are effective. The test result with the preference scores of 73.8% has shown the improvement of the naturalness of the synthetic speech through controlling the duration model parameters.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.1
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• pp.49-57
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• 2008

This study evaluated the flexural properties and fire resistance of polyolefm based structural synthetic fiber reinforced concrete. The effects of differing fiber length, dimension and fiber volume fraction were studied. Flexural and fire resistance test were conducted in accordance with the JCI SF-4 and RABT time heating temperature curve, respectively. The Flexural test results indicated that the polyolefln based structural fiber reinforcement showed an ability to increase the flexural toughness and good fire resistance significantly(as compared to steel fiber reinforcement).

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1354-1356
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• 2000

This paper deals with a 300kV dc charging system to be used ?s a voltage source in a circuit breaker synthetic short-circuit-test facility. Cockcroft-walton circuit is used to step up the rectified voltage from a single phase transformer of which primary winding is hooked up to an ac220 wall plug. Two systems with the same ratings have been designed and manufactured. The two system have been made of different supporting structure with different insulating materials. The paper describes a couple of charging schemes, system configurations and the synthetic test circuit in which the developed system is to be used.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.516-517
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• 2013

신재생 에너지의 비중 확대와 보급이 늘어남에 따라, 국가 간, 도시 간의 송전이 중요한 이슈로 대두 되고 있다. 위와 같은 요구 조건을 만족시키기 위해서 초고압 직류 송전의 개발이 필요하다. 초고압 직류송전(HVDC)에는 전류형과 전압형으로 나뉘는데. 각 HVDC에서 사용되는 Valve는 실제 운전 전에 여러 가지 방법으로 검증이 필요하다. 합성 시험회로 설비(Synthetic Test Circuit = 이하 STC)는 전류형 HVDC에서 사용되는 주요 전력변환 장치로, Thyristor Valve의 동작을 실제 동작 조건에 맞추어 동작을 시켜, 동작의 신뢰성을 검증하는 시험 설비이다. 본 논문에서는 전류형 HVDC Valve의 Operational Test를 위한 STC의 보호기능에 대해 기술하고 있다. 합성시험회로는 2상 초퍼와 6 펄스 사이리스터 컨버터를 사용하였고 설계된 보호기능은 PSCAD를 사용하여 검증하였다. HVDC Valve Operational Test시 합성시험회로 내에서 발생할 수 있는 사고 상황을 상정하고 그에 따른 보호 기능을 모의하였다.

• Journal of Ocean Engineering and Technology
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• v.22 no.5
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• pp.83-86
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• 2008

This paper deals with the experimental works for the correlations of ice resistance for icebreaker with synthetic(model) ice in general towing tank and with refrigerated ice in ice tank. In order to find out the correlation, the density variation is mainly focused in the present study. The model of Terry-Fox ice breaker has been used for the present correlation study because many data are available to be compared. According to the increase of density, the correlation becomes better quantitatively as well as qualitatively. Other parametric studies such as an ice size, a friction coefficient, a bending moment, etc., are also expected to be carried out to have better correlation in a near future. This research could be the basis for the possibility of resistance test using a synthetic ice in a general towing tank instead of an expensive ice tank.