• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1081-1083
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• 2003

In this paper, a new speed sensorless induction motor scheme which can work at any speed including the zero speed is presented. The proposed method is robust to secondary resistance variations. Simultaneous estimation of speed and secondary resistance are realized based on a feedforward type torque control scheme. The secondary flux with a low frequency sinusoidal waveform is used to help the estimation. Simulations results supported by experiments are given to show the effectiveness of this method.

• 한국생활과학회지
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• 제12권5호
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• pp.669-685
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• 2003

This research examined the work performance by consumer counselors, evaluations of their counseling work, the level of their satisfaction, and willingness to sustain consumer counseling work among Consumer Agencies and also identified the variables influencing the evaluation scores on those. The results were summarized as follows. First, the evaluation scores on the work performance of consumer counseling were generally high and they turned out to be generally satisfied with their work. On the other hand, most counselors responded that they would continue their counseling work. Second, there were differences in evaluation scores about speed and specialized area of counseling among Consumer Agencies. Counselors who worked for the Korea Consumer Protection Board recorded high scores in those both criteria. There were differences in the willingness of counselors to continue their counseling work among Consumer Agencies, too. Third, the evaluation scores in six areas of counseling tasks were high when the degree of satisfaction of counselors were high or when agencies treated the counseling important. Fourth, when counselors earned more salaries and owned the experience of in-firm training and when the Consumer Agencies highly valued counseling as consumer tasks, the degree of satisfaction among counselors increased. Finally, when counselors were old, major in consumer science, and held regular work-schedule, they exhibited high degree of satisfaction in their counseling work and they showed greater willingness to sustain their counseling work.

• 한국터널지하공간학회 논문집
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• 제21권4호
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• pp.561-571
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• 2019

NATM 공법을 이용한 터널굴착 시 발파공 천공 및 장약 작업은 전체 터널 굴착 시간의 30% 이상을 차지하는 중요한 과정이다. 최근에는 이 공정을 활용하여 천공작업 도중 얻어지는 타격압, 천공속도 등을 바탕으로 터널 굴착면 전방의 지반상태, RMR 등을 예측하는 연구들이 진행되어 왔다. 하지만 선행 연구들은 대부분 화강암으로 대표되는 화성암질 지반에 대해서만 수행되어 왔다. 본 연구에서는 유사한 RMR의 범위를 가지는 화성암의 천공속도를 퇴적암(특히, 역암, 사암 및 셰일)의 천공속도와 비교/분석하였으며, 유사한 RMR 값을 가지는 암이라 하더라도 암질 종류에 따라서 천공속도가 크게 달라질 수 있음을 확인하였다. 퇴적암에서의 천공속도가 화성암에서의 속도보다 더 빨랐으며, 또한 화성암의 경우 천공속도와 RMR등급에 따른 천공속도의 차이는 거의 없는 것에 반하여, 퇴적암의 경우는 RMR등급이 낮아질수록 천공속도는 증가함을 알 수 있었다.

• 대한교통학회지
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• 제34권6호
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• pp.535-547
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• 2016

본 연구는 고속도로의 공사구간의 사고 심각도에 영향을 미치는 주요인들을 파악하고 사고 심각도와의 관계를 규명하는 것을 목적으로 한다. 2011년부터 2015년까지 국내 고속도로에서 발생한 교통사고 자료를 공사구간 사고와 일반구간(비공사구간) 사고로 구분하였으며, 이 중 물피사고를 제외하고 분석에 활용하였다. 의사결정나무(Decision Tree)기법을 적용하여 공사구간과 일반구간의 사고 심각도에 영향을 끼치는 요인들을 파악한 뒤 사고 특성 및 영향요인의 차이점을 비교하였다. 특히 공사구간에서는 교통량이 많고 중차량 비율이 높을 경우 전반적인 구간속도 저하로 사고 심각도가 낮아지는 반면, 교통량이 적고 중차량 비율이 낮을수록 구간속도가 증가하여 심각도가 높은 사고로 이어지는 경향을 확인할 수 있었다. 본 연구를 통해 도출한 공사구간 사고심각도 영향 요인들은 공사구간 안전 관리 대책 마련에 도움을 줄 수 있을 것으로 기대한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 춘계학술대회 논문집
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• pp.132-136
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• 1996

A Study is a experiment which is figure out to aptimum discharge cutting condition of the surfaceroughness, electric discharging speed and electro wear ratio with Ton Toff and V(voltage) as an input condition according to the current(Ip) in an electric spark machine ; 1)Electrode is utilized Cu(coper) and Graphite. 2)Work piece is used the material of carbon steel. The condition of experiment is; 1)Current is varied 0.7(A) to 50(A). 2)Pulse time(Ton) is varied 3($\mu$s) to 240($\mu$s) and also Toff is varied 7($\mu$s) to 20($\mu$s). 3)The time of electric discharging to work piece in each time is 30(min) to 60(min) 4)After the upper side of work piece was measured in radius (5${\mu}{\textrm}{m}$) of syulus analyzed the surface roughness to made the table and graph of Rmax by yielding data. 5)Electro wear ratio is; \circled1Coper was measured cx-machining and post machining but the electronic baiance. \circled2The ex-machining of graphite measured by it, the post-machining was found the data from volume specific gravity and analyzed to made its table and graph on ground the data 6)In order to keep the accuracy of voltage affected to the work piece was equipped with the A.V.R(Automatic Voltage Regulator). 7)The memory scope was sticked to the electric spark machine. 8)In order to preserve the precision of current, to get rid of the noise occured by internal resistance of electric spark machine and to force injecting for the discharge fluid, it made the fixed table for a work piece to minimize the work error by means of one's failure during the electric discharging According to above results, the surface roughness by the variation of electrodw and current was analyzed to compare KS(Korea Standards) It was decided the optimum condition of electric discharge cutting through analyzing the effect of electric discharge speed and electro wear ratio.

• 한국산업정보학회논문지
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• 제18권6호
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• pp.61-70
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• 2013

본 논문에서는 ITS(Intelligent Transport System)인 VANET 환경에서 사고발생 시에 차량 속도와 방위각을 이용하여 경로 단절을 최소화시키면서 응급메시지를 신속하고 정확하게 전송할 수 있는 SARPE(Speed and Azimuth based Routing Protocol for Emergency) 시스템을 제안한다. SARPE 시스템은 다중 경로 탐색 및 경로 선정 작업 시에 불필요한 메시지 및 작업량을 최소화하기 위하여 방위각을 기반으로 경로 탐색을 수행하고, 근원지와 목적지 차량의 평균 속도와 탐색한 경로 내 차량 속도(최대속도, 최소속도)의 차를 이용하여 경로 단절 발생 확률이 적은 경로를 선택한다. 그 결과, 경로 단절로 인해 생기는 경로 재탐색 작업을 최소화하며, 응급메시지를 신속하고 정확하게 전송할 수 있다.

• 한국철도학회논문집
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• 제10권3호
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• pp.257-263
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• 2007

The critical speed above which the vehicle become unstable is one of the items that should be verified in the development of a new train. In the case of a high speed tilting train, which requires both higher critical speed and higher curving speed, the critical speed should be more carefully treated because the both requirements are in conflict with each other in the conventional train design. The main purpose of the present work is to estimate the linear and non-linear critical speeds of 200km/h Korean Tilting Train 'Hanbit200' under development. The newly developed self-steering mechanism was attached to the tilting train to ensure that the critical speed falls under the lower yaw stiffness which is needed to secure higher curving performance. The simulation for predicting the critical speed was done by a commercially available vehicle dynamics software. A full scale roller rig test was carried out to validate the numerical results and to verify the effectiveness of the self-steering mechanism.

• 한국기계가공학회지
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• 제9권6호
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• pp.29-35
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• 2010

Recently the industry high-speed machining has been applied to the automotive, aircraft, electronics parts machining because the effect of cost savings, machining time reduction and productivity improvement. In this study recently the aircraft structural aluminum alloy 7075 used in cutting the ball end-mill on the surface roughness terms most affect the parameters of the spindle speed and feed rate on the surface roughness of the work-piece according to the cutting depth is to investigate. Cutting depth at 0.3 mm has the lowest surface roughness.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권4호
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• pp.212-220
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• 2004

The present DC Motor or STEP Motor have been used in electronic work and products. There are many papers that let those Motor improved more conveniently in controlling and measuring those than before. By controlling and measuring those, the convenience of users and the functions of products can be improved. In addition, the responding speed of whole system can be increased by improving it of controlling and measuring. Therefore it is necessary that we develop motor motion application. Because of this necessity, neural networks was used to improve the responding speed of controlling and measuring, and a new application was developed for the convenience of users. This paper showed that efficiency of controlling methodology by neural-network is superior to others in correctness and speed. We are intend to verify its practical usefulness though experimentations.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.47-56
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• 1999

New rolling speed prediction model has been developed for the precise presetting rolling speed of each finishing mill stand in the tandem hot strip mill. Those factors such as neutral point, work roll diameter, rolling torque, friction coefficient, bite angle and the thickness at each side of entry and deliver of the rolls were taken into account. To consider width effect on forward slip, calibration factors obtained from rolling torque has been added to new prediction model and refining method has also been developed to reduce the speed unbalance between adjacent stands. The application of the new model showed a good agreement in rolling speeds between the predictions and the actual measurements, and the standard deviation of prediction error has also been significantly reduced.