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위치 오차 최소화를 위한 가변 릴럭턴스 레졸버 최적 설계
강정문,최길수 대한전기학회 2024 전기학회논문지 Vol.73 No.1
The precision of position estimation in VR resolvers significantly relies on the harmonic components present in the induced voltage across the secondary winding. The degraded accuracy can be compensated by carefully designing the stator windings and core geometry. This paper presents an optimized design process aimed at minimizing the position error of VR resolvers. The alterations in the resolver output signal's position information, resulting from the phase shift of the stator windings, third harmonic injection-based rotor geometry modifications, and changes to the stator core shape, are thoroughly analyzed using finite element analysis (FEA). Subsequently, a genetic algorithm-based optimization technique is applied to construct an optimal design process that effectively minimizes the position error in VR resolvers. Case study results demonstrate an approximately 80% enhancement in position estimation accuracy for the optimal model compared to the initial model.
한국과 탄자니아 초등학교 과학과 교과서의 삽화 비교 연구
강정문,이용섭 대한지구과학교육학회 2014 대한지구과학교육학회지 Vol.7 No.3
The purpose of this research is to examine the current state of inserting illustrations in science textbooks under the 7th Revised Educational Curriculum which is currently enforced in all grades of elementary schools, and to compare and analyze the external and internal differences in illustrations in science textbooks of elementary schools in Tanzania and Korea to present desirable direction of producing illustrations. There are not only some differences in rate of the kinds and role of the illustrations in grades, but also in both countries. In Korea textbooks, Photographs were mainly used to guide the students into experiments and to train the students in analyzing and interpreting data. In contrast, the Tanzania textbooks place more emphasis on pictures to enhance their interests and curiosity and understand. The Korea textbooks have to place more various illustrations instead of photos but the Tanzania textbooks should place more photos. As a result the addition of more diverse forms of illustrations and the re-organization of illustrations according to the topic should be considersd in future Korea and Tanzania textbooks.
마인드 맵 활용전략 과학수업이 과학탐구능력 및 과학 학업성취도에 미치는 효과
강정문,이용섭 대한지구과학교육학회 2014 대한지구과학교육학회지 Vol.7 No.2
The purpose of this study was to examine the effects of science lessons using mind mapping on creativity and academic achievement in science. The subjects of this study were fifth-grade students selected from four classes of an elementary school located in Busan. For ten weeks, the experimental group of 40 students were taught using the mind mapping technique. The comparative group, also of 40 students, was taught in normal classes which used a standard text-book. Children were given a test on science processing skills and academic achievement in science to measure the effects of mind mapping. The Likert scales were used to gather student`s feedback on creativity and academic achievement in science. Through these procedures, the following results were obtained: First, mind mapping had a greater effect on science processing skills than the normal classes, where a text-book was used. Second, mind mapping was effective in improving the student`s academic achievements in science at a greater level than the normal classes where a text- book was used. Third, after viewing results of the Student Recognition Investigation, we found that the students showed a higher level of interest in science lessons that used mind mapping, and were better able to understand the scientific theories. As a result, the elementary science class with mind mapping developed greater science processing skills and saw higher academic achievement in science. We conclude that science classes that use mind mapping have the potential to develop better science processing skills and improve academic achievement in science.
TAXUSTM 스텐트 시술 후 스텐트 혈전증 발생률과 임상경과
문재연,정명호,김인수,전충환,조정선,정종원,심두선,홍영준,김주한,안영근,조정관,박종춘,강정채 대한심장학회 2007 Korean Circulation Journal Vol.37 No.12
Background and Objectives : Findings from randomized controled trials have showed that there is no diference in the development of stent thrombosis (ST) -eluting stents (DES) as compared to the use of bare metal stents. The aim of this study was to evaluate the incidence, clinical characteristics, and cli-nical outcome of ST after implantation of TAXUSTM stents in routine clinical practice. Subjects and Methods : This was a retrospective, single center cohort study. The study included 1,584 patients that underwent sucessful TAXUSTM stent implantation (2,513 lesions treated) betwen May 2004 and Dec 2006. Results: ST developed in 18 patients (1.14%) (0.06%), subacute ST occured in nine patients (0.57%), and late ST developed in eight patients (0.51%). Sixteen patients that developed ST re-ceived medication with dual antiplatelet agents. The incidence of ST in patients with acute coronary syndrome (ACS) showed was higher than in patients with stable coronary disease. The mean folow-up duration for pa-tients was 13.3 months. There were 13 myocardial infarctions and 3 deaths attributable to ST. Conclusion : The TM stent implantation in consecutive real-world patients was substantially higher than the rate reported in clinical trials. Patients with ACS should be treated more aggressively as the risk of stent thrombosis is higher than for patients with stable angina. A large prospective study for the identification of predictors of DES thrombosis should be conducted. (Korean Circ J 2007 ;37:641-646) 배경 및 목적 최근 들어 실제 임상에서는 스텐트 혈전증의 빈도가 대규모의 계획된 임상연구들보다는 높다는 보고가 있으며 실제 임상에 계획된 임상연구의 결과들을 일률적으로 적용하는 것은 옳지 않다는 주장이 제기 되었다. 본 연구는 실제 임상에서 TAXUSTM스텐트를 삽입 받은 환자들을 대상으로 스텐트 혈전증의 빈도를 알아보고 이의 임상적 특징 및 치료 후의 경과에 대해서 알아보고자 진행되었다. 방 법 본 연구는 단일기관 후향적인 연구로 204년 5월부터 206년 12월까지 29개월간 전남대학교병원 심장센터에서 TAXUSTM스텐트를 성공적으로 시술 받은 총 1,584명 (2,51 병변)을 연구대상으로 하였다. 결 과 총 1,584명 중 18명 (1.14%)의 환자에서 스텐트 혈전증이 발생하였으며 병변의 수로는 0.72% (18/2511)의 빈도로 발 생하였다. 급성 스텐트 혈전증은 1명 (0.06%)에서, 아급성 스 텐트 혈전증은 9명 (0.57%)에서, 후기 스텐트 혈전증은 8명 (0.51%)에서 발생하였다. 스텐트 혈전증이 발생한 환자 중 16 명 (88.9%)에서 aspirin과 clopidogrel을 복용하고 있던 중에 발생하였다. 스텐트 혈전증의 임상적 발현 또한 심근경색증 으로 발현되는 경우가 13명 (72.2%)이었으며, 이 중 3명이 사망하였다. 결 론 TAXUSTM 스텐트 혈전증의 발생빈도는 실제 임상에서 1.14% 이었으며, 관상동맥 조영술로 확인을 하지 못한 채 사망한 경우 등 스텐트 혈전증이 의심되는 probable 혹은 possible stent thrombosis까지 고려한다면 실제 임상에서의 TAXUSTM 스텐트 혈전증의 빈도는 기존의 연구 결과 보다는 높을 것 으로 사료된다.