1,720,958 research outputs found
Cooperative braking control strategy for regenerative braking energy efficiency and vehicle stability of fuel cell hybrid electric vehicle
No full text학위논문(석사) - 한국과학기술원 : 기계공학전공, 2011.2, [ iv, 86 p. ]하이브리드 연료 전지 자동차는 무공해 친환경 차량으로서 파워 분배 및 회생 제동을 통해 연비 향상 효과를 얻고 있다. 연구 대상 차량의 전원은 연료 전지와 슈퍼 커패시터로 구성되어 있고, 두 전원간에는 직류-직류 변환기가 없는 구조로 이루어져 있다. 따라서 본 연구에서 다루고자 하는 상위 개념의 파워 분배 제어 로직은 버스 전압 변동에 의해 자동적으로 이루어 지게 되므로 정상 상태 모델링 기법을 이용하여 파워 트레인을 묘사하는 것에 국한 하도록 한다. 완성된 모델링을 통합하여 모의 시험 결과를 도출하고, 시간영역과 주파수 영역에서 모델링 검증을 위해 실제 차량 시험 결과와 오차 분석을 수행 하였다.
또한 전륜 구동 차량이므로 회생 제동은 오로지 전륜 구동 축에 직결 연결되어 있는 모터로부터 발생하게 된다. 하지만 이러한 구조적 한계로 인해 회생 제동 토크를 크게 인가하게 되면, 전륜의 횡력이 감소하게 되어 언더스티어 현상이나 휠 잠김 현상과 같은 차량 안전성을 잃는 문제가 야기 될 수 있다. 따라서 본 연구에서는 회생 제동 에너지 회수율 및 차량 안전성을 모두 고려한 회생 제동 협조 제어기를 제안 하도록 한다. 제안된 회생 제동 협조 제어기는 계층 구조를 갖고 있으며, 상부 제어기와 하부 제어기로 나뉠 수 있다. 상부 제어기는 LQR 제어 기법을 이용하여 목적 요 율 및 횡 미끄럼 각을 추종하도록 요 모멘트를 계산하도록 설계하였고, 하부 제어기는 등식(운전자 요구 제동력, 요 모멘트) 및 부등식 구속 조건(마찰원) 하에 최적 회생 제동 에너지 회수를 목적으로 회생 제동 및 마찰 제동을 최적 분배하도록 설계하였다. 또한 회생 제동 에너지 회수 목적 함수의 가중치 값을 언더스티어 계수의 함수로 표현 함으로서 차량의 안전성을 잃게 되는 극한 상황에서 발생하게 되는 큰 조향 부하를 방지 하도록 설계 하였다.
제안된 회생 제동 협조 제어기의 성능을 검증 하기 위해 상용화 된 다자유도 차량 동역학 시뮬레이션 CarsimTM 을 이용하였고, 추가적으로 제어기 성능에 영향을 끼치는 직/간접적 외부 요인들에 대한 민감도 분석을 통해 제안된 제어기의 강인성을 검증 하였다.한국과학기술원 : 기계공학전공
Clinico-histopathologic study on cysts of the jaw
No full text치의학과/석사[한글]
악골에 발생하는 낭종(악골낭종)은 구강내에 흔히 발생되는 질환으로 종양성 병변은 아니지만 악골을 흡수시키고 안모변형을 초래하기도 하며 드물게는 종양으로 이행되는 잠재력을 갖고 있다. 그러나 그 종류가 다양하고 발생기전 및 분류와 임상적 형태 또한 다양하여 이에 관해 많은 논란이 되고 있다. 이에 저자는 악골낭종의 진단 및 치료에 도움이 되고자 1981년 11월부터 1991년 11월까지 최근 10년간 연세대학교 치과대학구강병리학교실에서 검색하여 악골낭종으로 진단되었던 198예를 대상으로 1990년 세계보건기구에서 채택한 분류법을 기준으로 하여 발생학적 고찰과 병리조직학적 재검경을 통해 재분류하는 한편 임상적 특성을 연구한 바 다음과 같은 결론을 얻었다.
1. 총 198예의 악골낭종중 발육성치성낭종이 64예 (32.3%), 발육성비치성낭종이 13예 (6.6%), 염증성낭종이 107예(54.1%), 기타 14예(7.1%)였으며, 치근단낭종이 96예(48.6%)로 가장 많았고 함치성낭종이 36예(18.2%), 각화성낭종이 26예(13.1%)를 보였다.
2. 연령별로는 20대에 가장 호발하였지만 (26.3%), 발육성치성낭종은 모든 연령층에 고루 분포되었고 발육성비치성낭종은 20대 이전에는 발생되지 않았으며 발육성치성낭종은 10대에, 염증성낭종은 27대에 호발하였다. 성별 발생비율은 전체적으로 1.9:1로 남자에서 호발하였으나 각 유형별로는 남성:여성의 비율이 발육성낭종은 2.7:1, 염증성낭종은 1.7:1, 기타 0.6:1로 유형별 차이가 있었으며 특히 함치성낭종, 염증성치주낭종 및 잔류성낭
종에서 남성에 현저히 호발하였다. 부위별 분포로는 상악에서 67.3%, 하악에서 32.7%가 발생되었고 특히 상악전치부에 52.1%로 호발하였다.
3. 악골낭종의 주요한 주소로는 종창 (49.7%), 동통(19.8%) 및 농삼출(12.2%)등 심미적 이상이나 염증과 관련된 주소의 발현이 높았고, 우연히 발견된 예가 15.7%에 불과해 조기진단의 중요성을 시사하였다.
4. 악골낭종의 재발은 각화성낭종에서만 관찰되어 이 낭종 26예중 4예(15.4%)에서 재발을 보였는데 방사선사진분석상 이 낭종에서 특히 다방성 및 다발성의 빈도가 높았던 것으로 보아(46.3%) 각화성낭종의 높은 재발율은 조직학적 특성 뿐 아니라 다방성 및 다발성과도 관련이 깊은 것으로 사료된다.
5. 악골에 발생한 낭종으로부터의 중양이행율은 충 198예중 10예(5%)로 모두 법랑아세포종으로 이행되었고 유형별로는 함치성낭종 36예중 7예(19.4%), 각화성낭종 26예중 2예(7.7%) 및 석회화낭종 3예중 1예에서 이행되어 함치성낭종에서의 종양이행율이 특히 높았
으며 암종으로 이행된 예는 관찰할 수 없었다.
CLINICO-HISTOPATHOLOGIC STUDY ON CYSTS OF THE JAW
JI HUN HAN
Department of Dental Science, Graduate School, Yonsei University
(Directed by Prif. Hyung Sik Park, D.D.S., M.S.D., Ph.D)
Cystic lesions of the jaw bone are frequently encountered clinically. Although
they rarely lead to development of tumors, they can result in resorption of the jaw
bone or asymmetry of the face may occur. Due to the numerous varieties, origin and
clinical features of cysts, classification has been controversial.
The present study is aimed to help find better understanding for the diagnosis
and treatment of jaw cysts. The material used in this study consists of the 198
cases of jaw cysts examined at the Department of Oral Pathology, the Dental College
of Yonsei University, for the period of November 1981 to November 1991.
Classification recommended by the World Health Organization in 1990 was applied to
reclassify the 198 cases by the embryologic consideration and histopathologic
re-examination. All cases were analysed with clinical and radiological findings.
The obtained results were as follows.
1. Of the total 198 cases, there were 64(32.3%) developmental odontogenic cysts,
13(6.6%) developmental nonodontogenic cysts, 107(54.1%) inflammatory cysts, and
14(7. 1%) others. Radicular cysts numbering 96(48.6%) cases were the most common,
followed by 36 dentigerous cysts(18.2%), and 26 odontogenic keratocysts(13.1%).
2. By age group, the 20's accounted for the largest proportion of the cases
(26.3%). Developmental odontogenic cysts were found evenly in all age groups and
developmental nonodontogenic cysts were not found in age groups below the 20's.
Developmental odontogenic cysts were most common in the 10's and inflammatory cysts
in the 20's. When all cases were totaled, the male to female ratio was 1.9:1. The
ratio was 2.7:1 for developmental cysts and 1.7:1 for inflammatory cysts. In
particular, dentigerous cases of developmental odontogenic cysts and paradental
cases of inflammatory cysts were predominantly common in males. By locaion, cysts
on the maxilla accounted for 67.7% and the mandible 32.3%. The anterior teeth of
the maxilla were the most common location (52.4%).
3. The chief complaints were swelling(49.7%), pain(19.8%), and pus
discharge(12.2%), indicating that most complaints were related to inflammation and
facial asymmetry. The cases which were discovered accidentally accounted for only
15.7% of the total, which attests to the importance of early diagnosis.
4. Recurrence of jaw cysts were observed only in odontogenic keratocysts, with 4
recurrences(15.4%) among 26 cases. Radiological analysis revealed the high
recurrence rate was especially high in multilocular cysts and multiple
cysts(46.3%). This indicates that the high recurrence rate of odontogenic
keratocysts was related not only to histologic evidence but also to the
multilocular and multiple characteristics.
5. Of the total 198 cases, 10 cases with neoplastic change were all ameloblstoma.
Dentigerous cysts showed a high neoplastic change rate with 7 cases(19.4%) of 36,
fellowed by 2 cases among 26 odontogenic keratocysts (7.7%), and 1 case of 3
keratinization cases. Malignant change was not observed in this study.
[영문]
Cystic lesions of the jaw bone are frequently encountered clinically. Although they rarely lead to development of tumors, they can result in resorption of the jaw bone or asymmetry of the face may occur. Due to the numerous varieties, origin and
clinical features of cysts, classification has been controversial.
The present study is aimed to help find better understanding for the diagnosis and treatment of jaw cysts. The material used in this study consists of the 198 cases of jaw cysts examined at the Department of Oral Pathology, the Dental College of Yonsei University, for the period of November 1981 to November 1991.
Classification recommended by the World Health Organization in 1990 was applied to reclassify the 198 cases by the embryologic consideration and histopathologic re-examination. All cases were analysed with clinical and radiological findings.
The obtained results were as follows.
1. Of the total 198 cases, there were 64(32.3%) developmental odontogenic cysts, 13(6.6%) developmental nonodontogenic cysts, 107(54.1%) inflammatory cysts, and 14(7. 1%) others. Radicular cysts numbering 96(48.6%) cases were the most common, followed by 36 dentigerous cysts(18.2%), and 26 odontogenic keratocysts(13.1%).
2. By age group, the 20's accounted for the largest proportion of the cases (26.3%). Developmental odontogenic cysts were found evenly in all age groups and developmental nonodontogenic cysts were not found in age groups below the 20's.
Developmental odontogenic cysts were most common in the 10's and inflammatory cysts in the 20's. When all cases were totaled, the male to female ratio was 1.9:1. The ratio was 2.7:1 for developmental cysts and 1.7:1 for inflammatory cysts. In
particular, dentigerous cases of developmental odontogenic cysts and paradental cases of inflammatory cysts were predominantly common in males. By locaion, cysts on the maxilla accounted for 67.7% and the mandible 32.3%. The anterior teeth of the maxilla were the most common location (52.4%).
3. The chief complaints were swelling(49.7%), pain(19.8%), and pus discharge(12.2%), indicating that most complaints were related to inflammation and facial asymmetry. The cases which were discovered accidentally accounted for only 15.7% of the total, which attests to the importance of early diagnosis.
4. Recurrence of jaw cysts were observed only in odontogenic keratocysts, with 4 recurrences(15.4%) among 26 cases. Radiological analysis revealed the high recurrence rate was especially high in multilocular cysts and multiple cysts(46.3%). This indicates that the high recurrence rate of odontogenic
keratocysts was related not only to histologic evidence but also to the multilocular and multiple characteristics.
5. Of the total 198 cases, 10 cases with neoplastic change were all ameloblstoma. Dentigerous cysts showed a high neoplastic change rate with 7 cases(19.4%) of 36, fellowed by 2 cases among 26 odontogenic keratocysts (7.7%), and 1 case of 3 keratinization cases. Malignant change was not observed in this study.restrictio
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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