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최창주,서강성,박수강,조금배,백형래,임병옥 조선대학교 에너지.자원신기술연구소 2002 에너지·자원신기술연구소 논문지 Vol.24 No.2
Single phase induction motor(SPIM) is one of the most widely used type of low power AC motors in the world, especially for domestic or commercial applications where a three phase power supply is not available. Fractional horse power single phase induction motors have no starting torque their own. So there are several ways of starting single phase induction motors. The most common type is the starting capacitor installed in series with the auxiliary winding to increase the starting torque. Also, the auxiliary winding is disconnected once the speed of the motor reaches 70 to 80% of the rated speed. In the conventional systems, this function is conducted by a centrifugal switch. But the mechanical centrifugal switch has many problems such as switch malfunction. This paper presents the new methods of universal starting switch by digital controller to overcome these shortcomings of centrifugal switch.
확장된 칼만필터를 이용한 유도전동기의 센서리스 벡터제어
최연옥,정병호,조금배 조선대학교 에너지.자원신기술연구소 2000 에너지·자원신기술연구소 논문지 Vol.22 No.1
Using Observer, on the sensorless vector control system is a novel techniques for modern induction motor control. In this paper, a speed estimation algorithm of an induction motor using an extended kalman filter was proposed. Extended kalman filter can solve the problem, that have steady state error of estimated speed in flux and slip estimation method. The extended Kalman filter is employed to identify the speed of an induction motor and rotor flux based on the measured quantities such as stator current and DC link voltage. In order to confirming above proposal, computer simulation carried out control drives for using Matlab Simulink and show the effectiveness of the control drives for induction motor speed estimation.
최연옥,정병호,조금배 조선대학교 전자정보통신연구소 2002 電子情報通信硏究所論文誌 Vol.5 No.1
In this paper, a direct torque control(DTC) method of an induction motor is proposed which enables constant switching frequency. The switching strategy of a conventional direct torque control scheme which is based on hysteresis comparator results in a variable switching frequency which depends on the speed, flux, stator voltage and hysteresis band of the comparator. This paper proposes a new switching strategy which determine the effective switching time on each switching period by comparing the ascending and descending torque slopes. The simulation results are presented to verify this proposed scheme.
蓄熱用 TMA 包接化合物의 熱物性에 關한 實驗 硏究(Ⅰ)
최영범,한영옥,하옥남,김병철,김진흥 조선대학교 동력자원연구소 1996 動力資源硏究所誌 Vol.18 No.2
This paper presents the test-tube experimental results of thermal properties of TMA clathrate compounds for latent heat storage applications. The results are : ⅰ) subcooling in TMA clathrate compound is the lower than water, ⅱ) Phase change temperature in TMA clathrate compound is the higher than water. ⅲ) Latent heat of 25wt% TMA clathrate compounds of 220.4kJ/㎏K appear to be maximum. ⅳ) Comparing with water, volume of TMA clathrate compounds decreased as the phase change. ⅴ) TMA clathrate compounds precipitated because of increase of density as phase change. Thus, TMA clathrate compounds are found to be the promising compounds for the heat storage from the viewpoint of thermal property.
최병모,김경모,박형준,전희옥 한국교원대학교교육연구원 2006 敎員敎育 Vol.22 No.3
본 연구에서는 학교 사회과 경제교육에서 감성개발과 의사결정 및 문제해결 사고를 촉진하는데 크게 기여한다고 볼 수 있는 신문제해결학습 사례를 개발하여 적용해 봄으로써, 실험 결과에 따른 시사점을 도출하고 이를 바탕으로 학교사회과 경제교육의 발전에 기여하는 데 목적이 있다. 사회과 경제교육에서 신문제해결학습의 현장 적용에 따른 실증분석 연구를 통해 내릴 수 있는 결론을 제시하면 다음과 같다. 첫째로, 학교 현장에 적용 가능한 신문제해결학습 모형 수업 사례의 개발과 적용이 적극적으로 이루어져야 한다고 본다. 둘째로, 학교 사회과교실에서 신문제해결 수업모형을 활용함으로써 학생들의 자기주도적 학습능력 향상과, 고급사고력의 육성, 학습욕구 유발, 지식 기능 가치, 참여 등의 통합적 지도, 수행평가 가능 등의 측면에서 매우 긍정적인 교육효과를 얻을 수 있다고 보인다. 셋째로, 신문제해결학습 모형을 현장에 적용함에 있어서 발생 가능한 문제점으로, '시간부족', 모둠의 동질성 확보, 교실 현장의 교육과정 운영여건 성숙문제, 문제중심 교과 내용의 조직 필요성 등의 문제 등을 지적할 수 있다. 연구결과를 통해 볼 때, 학교 현장에 신문제해결학습이 원활히 정착되기 위해서는 이 수업운영에 필요한 사회과 경제관련 교육과정 구조전반의 변화가 요구된다고 본다. The Effect of A New problem Solving model in the Social Studies Economy Education was analysed in this thesis. The purpose of this study is, by making and verifying Experiment study of a new problem solving model and it's lesson in the social studies economis Education, as a result, to make a contribution to achieving the good economic education in the Korean social studies class room. In order to achieve this goal, firstly, theoretical background of a new problem solving model was discussed and it's lesson model has been made. Secondly, instrument(learning achievement ability, the opinion of the student and the teacher about a new problem solving model)that is, the experiment with a new problem solving model has been made. Thirdly, a new problem solving model lesson was applied in the classroom, and cause and effect by using statistical and interpretative method was analysed. And, we found a new problem solving model is more effective in terms of economic education than traditional instruction. In conclusion, we can propose the activation of a new problem solving model for economic problems resolution in knowledge centered society, the necessity of a new problem solving model in the social studies.
전옥철,김윤준,류범영,최재곤,조병욱,홍진후 조선대학교 생산기술연구소 1999 生産技術硏究 Vol.21 No.1
A series of wholly aromatic polyesters with side chains were synthesized by solution polycondensation from 2,5-dialkoxyterephthaloyl chlorides with the corresponding diol. The polymers showed the schlieren textures which is indicative of a nematic phase above their melting temperature. The inherent viscosities (η_(inh)) measured at 35℃ in phenol/p-chlorophenol/1,1,2,2-tetrachloroethane were 0.56-0.98 dℓ/g. The glass transition temperature (T_(g)) and melting temperature (T_(m)) decreased with increasing the length of the alkoxy side chain. Initial decomposition temperatures in TGA occurred at 338 ~ 363℃ in N₂ gas and thermal stability of polymers decreased with increasing the length of the side chain.
製造企業의 經營環境에 관한 硏究 : 김해지역을 중심으로
金東沃,孫炳基,金榮九,李道和,長英壹,崔容銑 인제대학교 1994 仁濟論叢 Vol.10 No.2
At the threshold of localization era, there is a great need to determine local economic development agenda. But current paucity of data regarding local firms' operations can be a hindering factor to achieve above objective. This study aims to provide such a data which can be used for setting local economic policy of Kimhae area. The study was conducted by administering survey questionnaires. The sample is 34 small sized manufacturers with less than 300 employees in Kimhae area. The content of survey includes General Management, Personnel and Labor Relations, Marketing, Production, Finance, Accounting and MIS. The results of survey revealed that current managerial practices in general showed sizable gap with desired one, which is mandated by national goal of reinforcement of competitiveness of small and medium sized firms.