• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 추계학술대회 논문집
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• pp.189-194
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• 2005

전국적으로 도로망이 확충되고 소득증대와 함께 주5일 근무제가 실시되면서 수상레저에 대한 국민의 관심이 증대되고 수상레저 스포츠의 활동인구가 증가하는 추세에 있다. 그러나 수상레저활동과 관련된 사고도 증가하고 있어 이를 어떻게 예방할 것인가 하는 것에 대해서 많은 논의가 되고 있다. 그 일환으로 1999년에 수상레저안전법이 제정되었고, 2005년에는 전면 개정이 이루어졌다 이에 따라 수상레저안전의 발전적인 방향을 모색하기 위해서는 수상레저인구를 대상으로 수상레저활동의 현황을 파악하고 수상레저안전법에 관련한 의식실태를 파악할 필요성이 있다. 이를 위해 수상레저활동자를 대상으로 개정된 수상레저안전법의 규제를 중심으로 설문분석을 실시하여 빈도분석과 교차분석 등을 통해 상호변수간의 연관정도와 상관관계 등을 분석하였다. 그 결과, 수상레저활동자들 중 $60\%$ 이상이 등록, 안전교육, 보험, 안전검사에 대해 각각 필요하다고 인지하고 있으며, 공통적으로 기구의 안전성에 대한 불만과 보험의 필요성에 대한 인지도가 높을수록 법적규제가 필요하다고 생각하는 경향이 있음을 확인할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.388-391
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• 2004

This research investigates how the fineness modulus of fine aggregates and the grain shape of coarse aggregates affects flow characteristics, packing characteristics and compressive strength characteristic. The experimental results, show that increase of the fine aggregate's fineness modulus improved concrete flow, but filling ability was high at over KS regulation extent due to segregation phenomena. It is considered that the improvement of 0.1 spherical rate was effective to concrete fluidity elevation by reducing about $6\%$ of fine aggregate ratio displays which the smallest gap rate of aggregate. Compressive strength was increased to about 0.6MPa everytime F.M. 0.1 of fine aggregate fineness is increased. However, it was decreased to about 9MPa at F.M. 3.5 compared to F.M. 3.0.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1038-1040
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• 1992

Booster is used widely as one of the step-up DC/DC power converter in power conversion process for fuel cell power plant which have the electrical characteristic of the high current density and low cell voltage. In view of control system, booster can be unstable when it is operated in broad operation range because the transfer function of booster has zero in right half plane of s-domain. So for reliable operation, controller must make the system stable in whole working range. In this paper, the two control method such as digital PID control and fuzzy control is studied for booster output voltage regulation in fuel cell plant. The design procedure of PID control and fuzzy control is described. And the experiment of designed controller action is performed in various operation points for controller performance test.

• 전기의세계
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• 제25권6호
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• pp.81-88
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• 1976

The present voltage-reactive power control aims at an overall coordination of reactive power sources and voltage regulation devices to keep the bus voltages within their allowable bounds on one hand and to reduce the transmission losses on the other. This paper presents an efficient computer control scheme for the real-time control of system voltage and reactive power on the basis of a simplified linear equation by using the system characteristic constant. Computational algorithm is used for the minimization of bus voltage deviation in the first phase of optimization and for the reduction of transmission losses under the constraint of vlotage settling condition in the second phase. The numerical example for sample practical system is also given. The present study on the computer control scheme will contribute to the automation of power system operation in the near future.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1172-1175
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• 2001

Recently, vector control without a speed sensor for an inverter induction motor system has been developed. In this paper describes the vector control system estimates rotor speed based on FMRAS(Flux Model Reference Adaptive System). Because of improving the initial condition and drift problem by pure integrator is eliminated, we can be expected to rapid responsibility of the speed estimation. The stability of speed estimator is proved on the basis of hyperstability theory. Proposed control system used TMS320C31 DSP for high speed processing. The effectiveness of the proposed system is verified by simulation and experimental results. This result shows that the highly characteristic speed estimation and robust character of load regulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 추계학술대회 논문집
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• pp.193-194
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• 2012

The bidirectional boost-buck chopper type AC voltage regulator is presented in this paper. The main characteristic of the AC chopper is the fact that it generates an output AC voltage larger or lower than the input AC one, depending of the instantaneous duty-cycle. Boost-buck chopper type AC voltage regulator, derived from the DC chopper modulated method, is a kind of direct AC-AC voltage converter and has many advantages: such as fast response speed, low harmonics and high power factor. It adopts high switching frequency AC chopper technique and can do wide range step less AC voltage regulation.

• 산업기술연구
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• 제29권B호
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• pp.41-45
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• 2009

The new cooling fan for various parts & equipments of KTX is developed and evaluated to improve fan performance and durability. The characteristic curve of the developed fan is obtained according to KSB 6311 of performance test regulation. 70 degree of the installation angle of blade makes the fan to produce a maximum flow rate. This angle is found out through trial-error and is confirmed through the verification test. In order to improve the blade strength, the blade is produced by a draw forming. The adoption of AL50 reduces a fan weight by 6 kg. The new blade makes a static pressure 170 (mmAq), a discharge rate $140(m^3/min)$, a rotational speed 2886 (rpm) at the power 10 kw. which results 54% of the static pressure improvement relative to the original blade.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.37-44
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• 2004

Automotive company has been endeavoring to develop high strength steels to get higher fuel efficiency of car since the oil shortage in 1970s and to cope with the recent strict environmental regulation. Outer panels(Hood, Roof, Door and Fender) for automobile require higher dent resistance. Bake-hardenable(BH) steels are known as useful for their high deep drawability and high dent resistance. Recently BH steels are increasingly adapted for outer panel use due to their high drawability and high dent resistance. In this study effect of temper rolling on formability (textures, r value) and bake hardenability is investigated fur improving characteristic of bake-hardenable steels.

• 전기학회논문지
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• 제56권12호
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• pp.2150-2156
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• 2007

According as level of industry develops day after day, electricity load system of industry requires high level control, effectiveness and high efficiency. Among supply and control unit of suitable power supply in these load characteristic, inverter systems of constant current regulate is used widely control of lighting and electric heating system. But, problems that power factor deterioration and fast response of control, efficiency, harmonics and etc are still remain. Therefore, in this paper proposed an inverter systems with constant current regulation and power factor correction (PFC) circuit for lighting and beaconing of aerodromes. The effectiveness of the proposed system confirmed through experimental results of 10[kW] power supply system.

• BMB Reports
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• 제36권6호
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• pp.580-585
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• 2003

Subtractive library hybridization was used to isolate the cDNA clones that corresponded to the transcripts that were specifically up-regulated during wheat embryo germination. The clones with numbers 5, 6, 7, 8, 24, and 26 appeared to be more abundant in germinating wheat embryos. Among the isolated clones, we identified four new members of the wheat "germin" gene family. We also identified two novel sequences which exhibited distinct germination up-regulation, and displayed characteristic spatial patterns of expression. One of these, represented by clone pSB10, was principally expressed in the root tissue of germinating embryos. The second was represented by the pSB7 clone and was expressed in both the root and shoot primordia of the embryonic axis, as well as within the coleoptile.