http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Signal Brush를 적용한 BLDC(Brushless DC) 모터 위치 검출
김시경,김영필 한국반도체디스플레이기술학회 2024 반도체디스플레이기술학회지 Vol.23 No.1
Recently, high-performance BLDC(Brushless DC) motors are being applied to various fields such as industrial and personal mobility devices and drones. To achieve the best performance of BLDC, sensors such as hall sensors, encoders, and resolvers are used to determine the position of the rotor, and various speed control technologies are being developed. However, due to problems with high-speed control due to external environmental factors and frequency bandwidth of semiconductor sensing devices, research on BLDC motors without semiconductor sensing devices is in progress. Therefore, in this study, a signal brush was added to the end of the rotor of a BLDC motor and the rotor position of the BLDC motor was detected by analyzing the signal output through the signal brush.
남자 대학생의 음주 형태 변화에 영향을 미치는 유전적, 심리사회적 요인
김시경,이수경,김민경,이상익 大韓神經精神醫學會 2007 신경정신의학 Vol.46 No.4
Objectives : This study aimed to determine the general predictive factors of change in drinking behavior and to provide materials for preventing drinking problems during early adulthood through examining genetic and psychosocial factors affecting the change of drinldng behavior in college students. Methods : The subjects were 101 male college students, apart of 534 students who had completed the previous study in 2000. In the present study as a 6-years follow up, we reassessed the drinking pattem and psychosocial variables and compared the results with previous data of the same subjects. To identify factors affecting the current drinking pattem, we used stepwise multiple regession and logistic regression analysis. Results : D allele (ALDH2) was found to reduce the degree of drinking and suppress problematic drinking, and C allele (TPH) had a suppression effect on problematic drinking. Drinking motive had a direct effect on the degree of drinking and Pro-blematic drinking. Negative cognitive expectancy had a direct effect on problematic drinking. Conelusion : Authors found some factors affecting the change of alcohol drinking behavior in college students and confirmed that there were hierarchies of significance among these factors. These may be applicable as variables for predicting drinking behavior in early adulthood.
김시경,정좌용 ( Si Kyung Kim,Jwa Yong Jeong ) 한국산림과학회 1985 한국산림과학회지 Vol.70 No.1
Growth and biomass production of natural stands of Quercus variabilis in relation to tree density were studied to obtain basic guide lines for future tending operation. Two natural stands of Quercus variabilis located at 900m (A stand: 6,600trees/㏊, 15.84㎡/㏊, 19/17-20) and 800m (B stand: 4,300trees/㏊, 16.65㎡/㏊, 20/17-21) elevation in Sancheong, Kyongnam Province were selected for the comparative study and following results were obtained through a sample plot method, After diameter of individual trees in the sample plots was measured, twelve average trees from each diameter class were cut felled to measure dry weight of W_S, W_B, W_L, W_(Ba), and standing biomass and biomass production rates by a allometrior regressions related to D²H. Vertical distribution of leaves along the stems indicated that photosynthesis was carried out 2.2m above the ground in Stand A and 1.2m in Stand B. Maximum photosynthesis was located 4.2m and 6.2m above the ground in Stand A and B, respectively. Leaf area index was 4.25㏊/㏊ for Stand A, and 3.89㏊/㏊ for Stand B. Above-ground standing biomass was 49.51 ton/㏊ for Stand A and 59.20 ton/㏊ and net annual production was 6.75 ton/㏊/yr. for Stand A and 8.99 ton/㏊/yr for Stand B. The ratio of net annual production to standing biomass was 17.5% for Stand A and 16.7% for Stand B. Net assimilation rate was 2.75㎏/㎏/yr. for Stand A and 3.58㎏/㎏/yr.for Stand B. Stem wood production rate was 1.46㎏/㎏/yr. for Stand A and 2.09㎏/㎏/yr. for Stand B. Bark production rate was 0.60 ㎏/㎏/yr. for Stand A and 0.34㎏/㎏/yr. for Stand B. Above data indicated that Stand B utilized growing spaces and sites more efficiently than Stand A. It is concluded chat productivity of natural stands of Quercus variabilis can be enhanced through optimization of basal areas and number of tree per hectare and that sound management of natural oak stands should be based on systematic: sampling of the area for periodic productivity estimation.
김시경,김연실 대한신경정신의학회 2011 신경정신의학 Vol.50 No.6
Objectives The aims of this study are to test the applicability of the continuing hospitalization judgement guidelines of The Primary Mental Health Review Board and to provide the basic data for the development of valid guidelines. Methods The request sheets submitted to Cheongju Primary Mental Health Review Board for continuing hospitalization from April 2009 to July 2001 were reviewed. The results according to the guidelines were compared with board’s final decision. The aim in making these comparison was to determine the factors affecting the board’s decisions. Results Cheongju Primary Mental Health Review Board assessed 1223 requests during the period, and declined 65 of those requests. The sensitivity and specificity for dissent of the algorithm in the guidelines are 51.6% and 97.0%, respectively. The patterns of data in the sheets from the mental facilities were different from the psychiatric hospital or the clinic. The presence of a guidance’s signature, mental status, and specialist’s opinion could be factors affecting the board’s decision. Conclusion The result suggests that distinguished guidelines are needed for mental facilities. Social support systems and functional impairments may be meaningless because they did not affect the board’s decision or could be replaced by other factors. The algorithm and judgement system should be revised to increase sensitivity for dissent. Further research is required concerning the development of standardized guidelines on the judgement for continuing hospitalization.
전력 변환 시스템의 고조파 저감에 대한 규격 및 역율개선 기법
김시경 대한전기학회 1995 전기의 세계 Vol.44 No.11
최근 전력변환장치 및 전동기 드라이버에서 전력용스위칭 소자의 사용 증가와 관련하여 고조파 저감 및 역율개선에 대한 관심이 증가되어지고 있다. 더욱이 유럽 및 미국에서는 전력변환 장치에 대한 고조파 저감 및 역율개선에 대한 규격들(IEC 555-2, IEEE 519)이 정립되어 많은 전기.전자 산업. 가전 제품들이 이 규격에 근거한 전고조파 왜형(total harmonic distortion)에 대하여 제한을 받고 있다. 적절히 설계되어진 역율개선(power factor correction) 회로들은 공급 전원과 동상이며 정현파형상의 전류를 상용 전원에 제공하며 규격에서 제한된 고조파 성분을 제거하는 역할을 한다. 본고에서는 이들 고조파 제한에 관한 규격에 대하여 고찰하고 전력 변환 장치에 대한 입력전원의 고조파 저감 및 역율개선에 대하여 지금까지 개발 및 연구되어진 PFC 회로 및 제어기법에 대하여 고찰하고자 한다.