북한 선교의 장,단기 전략

손정훈 장로회신학대학교 신학대학원 2000 국내석사

韓國 公共組織의 效果的 팀제 導入 戰略에 관한 硏究 : 行政自治部·KOTRA·LG化學 事例 比較 分析을 中心으로

손정훈 서남대학교 대학원 2007 국내박사

Team system cannot secure its success until appropriate process suitable for the organization is introduced. That is, it is difficult to simply integrate a successful team to the public organization, in which there are big differences in the organizational characteristics, even if the team is successful for general corporations. Therefore, appropriate introduction process, in accordance with the organization, should be passed through. Each ministry and office of central government is introducing the team system as a way of organization renovation with the introduction of team system that started with the Ministry of Government Administration and Home Affairs, in March 2005. This paper elucidates the appropriate strategy of team system, suitable for the organization, in order to establish successful team systems in public organizations and enhance its effect as a way of adapting the new environment in the rapidly changing administrative environment of central government. Under the awareness of these problems, this paper attempted to understand the causes of system change and suggest of effective team system and strategy to general organizations preparing for it, especially public organizations, by clarifying what environments and elements are factors that influence system changes and how they are applied in terms of general organizations and policy changes by analyzing the case studies of the process of successful team system, successfully introduced by various subjects until now. For this, this paper analyzed the introduction process of team system to public institutions, public enterprises, and private enterprises, which are evaluated as the introduction of comparatively successful team system in order to draw the success factors of team system, especially introduction process. The summarizations about the results of case studies on the introduction process of team system by the Ministry of Government Administration and Home Affairs, KOTRA, and LG Chemicals are as follows: First, the Ministry of Government Administration and Home Affairs is reforming the conventional and inefficient organizations, KOTRA is getting out of the operation of typically inefficient corporations, and LG Chemicals is introducing the team system in order to solve the problems of the slowdown of corporation growth, the increase of organization, the over growth of organization size, the acceleration of promotion backlog, the decline of morale, aging of high position people, and the aggravation of labor cost. Second, seeing the results of case studies, the Ministry of Government Administration and Home Affairs, KOTRA, and LG Chemical reorganized all sorts of systems, supporting the introduction of team system, and this systematic consolidation was better performed in the Ministry of Government Administration and Home Affairs and public enterprises such as KOTRA than in private enterprises such as LG chemical. Third, all study objects commonly introduced the task force, set the principle of appropriate division of work, and tended to transfer the authority of settlement to the subordinate while downsizing the stages of settlement in both private enterprise and public sector. Fourth, the subordinate class of public sector did not feel the necessity of team system in the introduction process and reacted passively, while the chief officers revealed strong willingness and support of team system, and in the private enterprise, the willingness of chief officer to introduce the system was very aggressive, and the organization members sympathized with the necessity of team system and they were actively engaged in the team. Fifth, in the public sector, the aggressive willingness of chief officers was strong, while the sharing of objectives among members and concreteness of those objectives were rather low, whereas LG Chemicals shared the team objects with concreteness. In such way, as a result of analyzing, summarizing, and evaluating the cases of team system introduction process, the conclusions are drawn as follows: First, the Ministry of Government Administration and Home Affairs and KOTRA focused on the reconsideration of efficiency within the organization, and LG Chemicals put weight on resolving the interior problems such as the backlog of promotion, ageing, the increase of high positions, and the burden of labor cost. Second, the consolidation service and establishment of relevant systems were actively carried out. Study objects introduced new evaluation system and reward system, and established the information system. Third, the team system types of all study objects were similar to the large team system and task force team, and settlement stages were readjusted downwardly below the team leader and broadly reduced under the line of team leaders or general managers. Fourth, the strong willingness of introduction and support of chief executive officers were working significantly in the study objects, and in the introduction process of team system, all sorts of authorities and responsibilities were appointed to team leaders, along with the demand of the role of team leaders and leadership. Fifth, when the attitude on the introduction of team system is examined, the strong willingness of the chief officers was important as a driving force, but the sharing of objectives and concreteness was rather low in the public sector. Based on the study results above, the perspective of effective introduction of team system in public organizations, which hold a fixed and thoroughly bureaucratic culture, is as follows: First, in order to cope with the rapidly changing environment and expand the service of customer centered administration, traditionally hierarchical organization should be transferred to the team system organization in the public organization. Second, a team system that is suitable for the features of public organization should be introduced. If public organization ignores the features of public organization, and attempts the introduction only with the reason that it has improved the efficiency of private organization, the possibility to fail is higher than that of success. Third, the type of team system that should be introduced in the public organization should be of a task force type so that the size of team system should begin with the current large scale team system of department unit and be gradually downsized to a small scale team system of division unit, which can enhance efficiency, in consideration of current duty and bureaucratic tendencies. Fourth, the introduction of team system should be recognized by all members of an organization, and members should lead the participation of all staff rather than outside promotion of the introduction of team system. Fifth, team system needs to be introduced by phases, and especially, the objective of team system should be divided into long-term and short-term concretely and clearly. Sixth, the reorganization or complement of relevant system is needed along with the introduction of team system. However, gradual complement or reorganization is needed rather than considerable chaos or unexpected side effect because of temporary complement, revision, and new establishment of system. Seventh, an operation that counts on its team leader excessively can cause a low outcome of the whole team or undesirable results, such as trouble within the team. Eighth, the willingness of introduction and support by the chief officer or top management are important in the success of team system. This paper has several limitations as follows: First, it was not reasonable to evaluate the outcome of cases of the Ministry of Government Administration and Home Affairs and KOTRA, with the exception of LG Chemicals, which introduced team system a long time ago, because of short period of introduction. Nonetheless, public institutions and the sector of public enterprise were selected as cases because other appropriate cases were not found. Second, multidimensional access is needed because team system requires the whole change of organization. In this sense, this paper has limits in that it analyzed only selected factors of the introduction, operational system equipment, structure, maintenance, and systematic support of team system. Third, it is believed that more desirable introduction of team system can be suggested by analyzing team system through connecting the introduction process and the outcome of team system in the case analysis process of team system. However, due to the lack of documents, related to outcome, the connection between the process and outcome of team process could not be sufficiently considered. First of all, in depth study should be conducted with the pluralizing case study objects of team system and finding more appropriate cases. In addition, the development of index, measuring the introduction outcome of team system concretely and its applicationare required in order to enhance the objectivity of case studies. In addition, the objectivity of analysis should be enhanced by developing a standardized index, which is an analysis index that is related to the study of team system, and concrete casual relationships should be drawn by connecting analysis index with the outcome of team system. 팀제는 그 조직이 가지고 있는 특성에 적절한 도입 과정을 거쳐 도입되어야만 비로소 그 성공을 담보할 수 있을 것이다. 즉, 일반 기업들이 성공적으로 운영하고 있는 팀제라고 해서 조직적 특성에 큰 차이가 있는 공공조직에 그대로 단순히 접목시켜서는 성공적인 정착을 기대하기가 어려우며, 그 조직에 맞는 적절한 도입 과정을 거쳐야만 할 것이다. 중앙정부는 2005년 3월에 행정자치부가 정부 최초로 본부·팀제 전면 도입을 시작으로 인하여 중앙기관의 각 부처에서는 조직혁신의 일환으로 속속 팀제를 도입하고 있다. 오늘날 급변하는 행정환경 속에서 중앙정부가 이러한 환경변화에 보다 유연하고 신속하게 적응하기 위한 하나의 방안으로 일반조직 특히 공공조직의 팀제가 성공적으로 정착되어 효과를 발휘할 수 있도록 하기 위해서는 그 조직에 적합한 팀제의 도입 전략을 체계적으로 규명 하고자 한다. 이러한 문제 의식하에서 본 연구는 그동안 다양한 주체들에 의해 비교적 성공적으로 도입된 팀제 도입 과정을 사례 분석하여 일반적인 조직과 제도변화라는 차원에서 어떤 환경과 요소들이 제도변화의 영향 요인이고 그것은 어떻게 작용하는가를 밝힘으로써 제도변화의 동인을 파악하여 팀제 도입을 준비하고 있는 일반조직 특히 공공조직에 효과적인 팀제 도입 전략을 제시하는데 그 목적이 있다. 이를 위해 본 연구에서는 비교적 성공적으로 팀제를 도입하였다고 평가되고 있는 공공기관, 공기업, 사기업을 대상으로 팀제 도입 과정을 분석하고 팀제 도입의 성공 요소 특히 도입 전략을 도출하고자 한다. 본 연구에서 행정자치부, KOTRA, LG화학에서의 팀제 도입 과정을 사례 분석한 결과를 요약하면 다음과 같다. 첫째, 먼저 행정자치부는 공무원 조직으로서 관행화된 비효율적이고 비능률적인 조직의 혁신을, KOTRA는 전형적인 비능률 기업에서의 탈피를, LG화학은 기업 성장의 둔화 및 조직증감과 조직규모의 비대화 문제와 승진적체 가속화와 구성원의 사기 저하, 중고령화·고직급화 현상, 인건비 부담 가중 등을 해소할 목적으로 각각 팀제를 도입하고 있다. 둘째, 사례 분석 결과를 보면 행정자치부나 KOTRA나 LG화학 등 모두 팀제 도입과 함께 팀제 도입을 지원하는 각종 제도를 정비하였으며, 이러한 제도적 정비는 사기업인 LG화학에 비해 공공기관인 행정자치부나 공기업인 KOTRA에서 더 많이 이루어진 것으로 나타나고 있다. 셋째, 연구 대상 모두 공통적으로 우리나라 현실에서 도입되는 팀제가 대부대과제를 도입하고 있으며, 적절한 업무분담 원칙을 설정하고 있으며, 사기업이나 공공부문 모두 결제 단계를 모두 대폭 축소한 가운데 결제 권한을 하부로 크게 위양하는 경향을 보이고 있다. 넷째, 팀제가 도입되는 과정에서 공공부문에서는 하위 계층이 그 필요성을 크게 느끼지 못하면서 소극적이었던 반면 최고 책임자들이 적극적인 도입 의지와 지원을 하였고, 사기업에서도 최고경영자의 도입 의지와 지원이 매우 적극적이었으나 조직 구성원들도 팀제 필요성을 공감하고 적극 참여하는 양상을 보였다. 다섯째, 공공부문은 최고관리자의 적극적인 도입 의지에 의해 추진되면서 구성원들간의 목표공유와 구체화는 다소 떨어지고 있는데 반해 LG화학은 팀내 목표에 대해 공유되며 구체화하고 있다. 이와 같이 팀제 도입 과정을 사례 분석한 결과를 종합하여 평가하면 다음과 같은 결론을 얻을 수 있다. 첫째, 팀제 도입의 목적을 보면 행정자치부와 KOTRA는 조직 내부의 효율성 제고에 초점이 맞추어져 있고, LG화학은 승진적체, 중고령화·고직급화, 인건비 부담 가중 등 내부적인 문제 해결에 초점이 맞추어져 있다. 둘째, 팀제 도입과 함께 관련제도의 정비 및 구축이 활발히 이루어졌다. 연구 대상들은 팀제 도입과 함께 새로운 평가제도와 보상제도를 도입하였고, 그리고 정보 시스템을 구축하였다. 셋째, 연구 대상 모두 도입한 팀제 유형은 대팀제나 대부대과제로 유사하였으며, 결제 단계도 팀장 이하로 대폭 하향 조정하거나 팀장 및 본부장 선에서 종결되도록 대폭 축소하였다. 넷째, 팀제의 도입에 있어서 연구 대상들은 최고경영자의 적극적인 도입 의지와 지원이 크게 작용하고 있었고, 팀제 도입 과정에서 팀장에 대한 역할과 리더십을 크게 요구하면서 팀장에 대해 각종 권한과 책임을 부여하고 있다. 다섯째, 팀제 도입에 대한 구성원의 태도를 보면, 먼저 공공부문은 최고관리자의 적극적인 도입 의지에 의해 추진되면서 구성원들 간의 목표 공유와 구체화는 다소 떨어지고 있다. 이상의 연구 결과를 토대로 관료적 성향이 강한 우리나라 조직 특히 오랫동안 고착화된 철저한 관료주의적 문화를 가지고 있는 공공조직에서 팀제를 효과적으로 도입하기 위한 시사점을 보면 다음과 같다. 첫째, 무엇보다도 급격한 환경변화에 대응하고 수요자 중심 행정 서비스 공급을 확대하기 위해 공공조직에서도 전통적인 계층제 조직에서 팀제 조직으로 전환되어야 한다. 둘째, 공공조직 특성에 적합한 팀제를 도입하여야 한다. 공공조직은 공공조직의 특성을 무시하고 팀제가 사조직에서 효율성을 제고할 수 있다는 이유만으로 도입을 시도한다면 성공보다는 실패할 가능성이 높아진다. 셋째, 공공조직에서 도입해야 할 팀제 유형은 대부대과형으로, 팀제 규모는 현재의 업무나 관료적 성향을 감안할 때 현재의 부 단위 수준의 대규모 팀제로 시작하되 점차 효율성이 높은 과 단위의 소규모 팀제로 축소해 나가야 할 것이다. 넷째, 팀제 도입을 외생적으로 추진되기 보다는 조직 구성원들이 모두 그 필요성을 인식하고 전 직원이 모두 동참할 수 있도록 추진되어야 한다. 다섯째, 팀제는 단계적으로 도입할 필요가 있으며, 특히 팀제 도입의 목표를 구체적이고 명확하게 장단기로 나누어 설정될 필요가 있다. 여섯째, 팀제 도입과 함께 관련제도를 개편하거나 보완하는 것이 필요하다. 그러나 이러한 제도의 보완·개선·신설 등이 일시적으로 이루어져 상당한 혼란이나 예기치 못한 부작용을 초래하기 보다는 점진적인 보완이나 개편이 요구된다. 일곱째, 팀 운영과 관련하여 지나치게 팀장 중심의 운영은 팀 전체의 성과를 낮추거나 팀내 불화 등 바람직하지 않은 결과가 초래될 수도 있다. 여덟째, 팀제의 성공 여부에는 무엇보다도 최고책임자 혹은 고위관리자의 적극적인 도입 의지와 지원이 중요하다. 본 연구는 다음과 같이 몇 가지 한계점을 가지고 있다. 첫째, 사례 분석 대상으로 선정된 사례들이 도입 된지가 오래된 LG화학을 제외하고는 행정자치부나 KOTRA의 사례는 아직 도입 된지 몇 년이 되지 않아 그 성과를 평가하기가 무리이다. 그럼에도 불구하고 공공기관과 공기업 부문에서 적당한 여타 사례가 없어서 이를 사례 분석하였다는 한계점이 있다. 둘째, 팀제라는 것은 조직 전반에서의 변화를 요구하는 것이어서 보다 다차원적인 접근이 필요함에도 불구하고, 본 연구에서는 팀제 도입 과정에 대한 분석을 팀제 도입의 토대적 요인, 운영 체계 정비, 조직 구조 정비, 제도적 지원 체계 정비 등을 한정하여 분석하였다는 한계점이 있다. 셋째, 팀제의 사례 분석 과정에서 팀제의 도입 과정과 팀제의 성과를 연계하여 분석함으로써 보다 바람직한 팀제 도입 과정을 제시할 수 있을 것이나 본 연구에서는 성과에 관련된 자료가 부족하여 이들 간의 연계성을 충분히 고려하지 못했다는 한계점을 가지고 있다. 이상의 연구 한계점을 토대로 향후 연구는 다음과 같은 방향을 고려하여 이루어질 필요가 있다. 먼저, 팀제 사례 연구 대상을 보다 다원화하고, 적절한 사례를 대상으로 보다 심층적인 연구가 이루어져야 할 것이다. 이 과정에서 팀제 도입 성과를 구체적으로 측정하는 지표를 개발하여 이를 적용함으로써 사례 연구의 객관성을 높여야 할 것이다. 또한, 팀제 연구와 관련된 분석 지표를 보다 표준화된 지표로 개발하여 분석의 객관성을 높여야 할 것이며, 구체적으로 이들 지표가 팀제 성과와 연계함으로써 보다 구체적인 인과 관계를 도출할 필요가 있다.

사이버특수대학원 학생의 입학목적, 학습동기 및 학습전략의 관계 연구

손정훈 계명대학교 교육대학원 2014 국내석사

본 연구의 목적은 사이버특수대학원 학생의 입학목적, 학습동기, 학습전략 간의 관계를 규명하는 것이다. 이러한 목적을 달성하기 위해서 다음과 같이 연구 문제를 설정하였다. 첫째, 사이버특수대학원 학생의 입학목적이 학습동기에 미치는 영향은 어떠한가? 둘째, 사이버특수대학원 학생의 입학목적이 학습전략에 미치는 영향은 어떠한가? 셋째, 사이버특수대학원 학생의 학습동기가 학습전략에 미치는 영향은 어떠한가? 본 연구에서는 B사이버특수대학원 재학생 67명을 대상으로 학습동기전략검사(MSLQ)를 실시하였다. 수집된 자료는 다중회귀분석의 방법으로 분석하였다. 본 연구의 결론은 다음과 같다. 첫째, 사이버특수대학원 학생의 입학목적 중 개인 가치충족은 학습동기 중 내재적 동기와 과제가치에 영향을 미친다. 둘째, 사이버특수대학원 학생의 입학목적 중 개인 가치충족은 학습전략 중 조직화에 영향을 미친다. 셋째, 사이버특수대학원 학생의 학습동기 중 과제가치는 학습전략 전반에 유의한 영향을 미친다. The purpose of this study was to investigate the relationships among enrollment purposes, learning motivation, learning strategies of cyber special graduate school students. To achieve the purpose, following research questions have been established: First, how do enrollment purposes of cyber special graduate school students affect their motivation for learning? Second, how do enrollment purposes of cyber special graduate school students affect their strategies for learning? Third, how does learning motivation of cyber special graduate school students affect their strategies for learning? 67 students from B cyber special graduate school responded on a questionnaire, Motivated Strategies for Learning Questionnaire(MSLQ). The data were analyzed using multiple regression analysis. Results were as follows: First, personal value satisfaction among enrollment purposes of cyber special graduate school students has a positive effect on intrinsic goal orientation and task value among the factors of learning motivation. Second, personal value satisfaction among enrollment purposes of cyber special graduate school students has a positive effect on organization among the factors of learning strategies. Third, task value among learning motivations of cyber special graduate school students affects on most of learning strategies.

피카소의 입체주의에 대한 연구 : 회화를 중심으로

손정훈 한남대학교 1994 국내석사

가변용량형 사판식 액셜피스톤 펌프의 모델링 및 사판 강인 제어기 설계

손정훈 부산대학교 2007 국내석사

In typical hydraulic control systems, the valve control method is widely employed because it is easy to design and control and it has better response characteristics rather than the pump control method. In respect of energy efficiency, however, it is essential to apply the pump control method which can supply necessary amounts of flow rates and pressure to the hydraulic systems. In this study, the focus was given to the control of inner pressure of control cylinder for the swash plate control. In order to design a precise and robust controller, mathematical model for swash plate control system of variable displacement axial piston pump was identified based on signal compression method. Based on the identified mathematical model, robust swash plate controller was designed by considering variation of load pressure. Consequently, the precise and robust swash plate control characteristics are verified from the experiments.

휴대전화에서의 3D GIS 데이터 표현을 위한 모델링과 성능평가에 관한 연구 : HI Mascot Capsule Engine을 사용하여 : using HI Mascot Capsule Engine

손정훈 서울대학교 대학원 2007 국내석사

Alteration of low density operation range by resonant magnetic perturbation in KSTAR

손정훈 서울대학교 대학원 2016 국내석사

Knowing the operation range of tokamak is important since the operation parameters determine the fusion output power and plasma operation scenarios. In this thesis the operation range of KSTAR was revealed via Hugill diagram and Greenwald density fraction diagram. In total 1740 experimental shots were selected carefully for this analysis which were performed from 2011 to 2014 in KSTAR. By comparing the operation range of KSTAR with that of DIII-D via Hugill diagram, it was found that KSTAR can reach far lower density, insisting that KSTAR has extremely low intrinsic error field. The range of the achievable Greenwald fraction of KSTAR was shown to be 6% to 60% in the present database. The two factors, runaway electron and error field, which can alterate the achievable low density operation range were investigated. The condition for the generation of the runaway electron in KSTAR was found via Dreicer condition with dedicated runaway electron generation experiments. Although these experiments satisfy the condition for generating runaway electrons, all of these shots could be sustained without significant interruptions. Based on this observation the runaway electrons are not thought to be the main factor to set the low density operation limit in KSTAR. On the other hand, plasma shots with the increased error field by applying the resonant magnetic perturbation(RMP) often showed the plasma locking phenomenon so that access to the low density operation range was significantly constrained. The plasma locking threshold is found to be differed by the position of the applied RMP coil and the value. The RMP coil current magnitude needed for plasma locking from the middle coil is about half of that from the top or the bottom coil. And the lower value showed the lower density operation range, with in cases and in cases. The influence of RMP to the low density range is investigated in terms of the L-mode to H-mode transition power which shows that access to the optimal density range of the L-H transition can be limited by applying RMP. Therefore, it is suggested to take this effect into account in designing operation scenarios for tokamaks employing RMP to suppress edge localized modes in H–mode plasmas in particular.

대기 중 미세먼지 농도에 따른 한국 태양광 발전량 변화

손정훈 서울대학교 대학원 2021 국내석사

As the use of renewable energy is globally increasing to reduce the consumption of fossil fuels that cause global warming, the government of the Republic of Korea will increase the portion of renewable energy to total energy production following the policy ‘Renewable Energy 3020’. Since energy production from solar photovoltaic (PV) power generation is the largest renewable energy source, the projection of solar PV power generation over the Republic of Korea is important for developing energy policy. This study investigated the impact of atmospheric concentration of particulate matter (PM) on solar PV power generation using the recorded solar PV power generation at two power plants located at Yeongam and Enpyeong-gu as well as the observed dataset for meteorological parameters and atmospheric concentration of PM2.5 and PM10 at the nearest stations. The analysis period is 2015-2019 and 2015-2017 for Yeongam and Enpyoeng-gu, respectively. As a result of a multilinear regression analysis based on the solar PV power generation and four independent variables such as insolation, temperature, relative humidity, and PM concentrations, solar PV power generations are substantially decreased by PM concentrations at both power plants. The reduction rates of solar PV power generation due to PM2.5 concentration reaches 20.8% and 15.6% at Yeongam and Enpyeong-gu power plants, respectively, under the ‘bad’ air quality condition, 75 μg m-3. Also, the negative impact of PM10 on solar PV power generation exceeds 23% at both stations under the ‘bad’ air quality, 150 μg m-3. Our results show that the reduced solar PV power generation due to atmospheric PM concentration should be considered for planning the country’s energy policies. 전 세계적으로 지구온난화의 주요인으로 지목된 화석연료의 사용을 줄이기 위해 에너지 생산량에 재생에너지의 비중을 늘리고 있다. 이에 따라 한국도 ‘재생에너지 3020 이행계획’을 발표하고 재생에너지를 이용한 발전량을 늘릴 예정이며, 이 계획의 핵심이 되는 것은 태양광 에너지이다. 따라서 한국에서의 태양광 발전량 및 발전 효율에 대한 연구는 미래의 에너지 계획에 매우 중요하다. 본 연구에서는 대기 중 미세먼지의 농도가 태양광 발전량에 끼치는 영향을 정량적으로 분석하였다. 이를 위해, 2015년부터 2017년까지의 전라남도 영암군에 위치한 태양광 발전소와 2015년부터 2019년까지 서울 은평구에 위치한 태양광 발전소의 실제 시간당 발전량 데이터와 미세먼지 및 기상자료에 다중회귀분석 방법을 적용하였다. 또한, 청명일사분석법을 적용하여 구름의 효과를 제거 후, 미세먼지 농도의 효과를 파악하였다. 다중회귀분석 결과, 태양광 발전량은 일사량에 비례하고 기온과 습도, 미세먼지 농도가 증가할수록 감소하였다. 분석 결과를 바탕으로 현재 한국에서 사용 중인 통합대기환경지수에서 제공하는 대기질 기준을 이용하여 대기 중 미세먼지 농도의 영향을 파악하였다. PM2.5 및 PM10 농도에 따른 대기질 ‘나쁨’의 기준을 적용할 경우, 영암발전소에서의 태양광 발전량은 20.8% 및 23.7% 감소하였으며, 은평발전소의 경우, 15.6% 및 23.7% 만큼 감소하였다. 본 연구의 결과는 대기 중 미세먼지 농도가 태양광 발전량에 큰 영향을 끼치고 있음을 명확하게 보여주며, 이 결과는 태양광 발전량 예측 모델 수립 및 미래의 태양광 발전량 예측과 그에 따른 정책 수립에 도움이 될 것이다.

Neospora caninum의 자연 감염율, 송아지로의 전파양상 및 유산관련 요인들의 상호관계 변화에 대한 연구

손정훈 忠南大學校 大學院 2011 국내박사

This study examined the histopathology, immunohistoch- emistry, and electron microscopic findings of aborted fetuses from pregnant dairy cows naturally infected with Neospora caninum (N. caninum) at four farms in Gongju city and Yeonki gun of Choongnam province. To examine the seroprevalence of N. caninum infections in cattle raised at farms where an abortion had previously occurred in Gongju city and Yeonki gun of Choongnam province, 280 heads of cattle from six farms were examined by ELISA. Thirty-two pregnant cattle from four farms were examined to determine the abortion rate in naturally N. caninum-infected pregnant cattle and the infection pattern in newborn calves. And the potential relationship between pregnancy outcomes and levels of IFN-γ, hormones, and antibodies in naturally N. caninum-infected cows was examined in the blood samples collected every 2 or 4 weeks in 26 pregnant cows from four farms. Systemic subcutaneous edema was observed in the aborted fetuses. The necropsy revealed considerable serosanguinous fluid was observed in the body cavity of the aborted fetuses. Light microscopy showed the infiltration of many inflammatory cells consisting of macrophages, lympho- cytes and mononuclear cells, accompanied by the congestion, hemorrhage and the necrosis of myocardiac cells and hepatocytes in the liver and heart of the aborted fetuses. In the liver, clusters of tachyzoites were formed in the cytoplasm of hepatocytes and the interstitial tissue. In the brain, many tissue cysts with various sizes were observed in the nerve cells and their adjacent areas. Tissue cysts had a round shape and contained a large amount of bradyzoite. In addition, there was diffuse gliosis accompanied by congestion and hemorrhage and focal necrosis in the brain. The infiltration of microglial cells were observed at the periphery of the focal necrosis and perivascular area in the brain. Multifocal necrosis of the fetal placenta and hemosiderosis was observed in maternal placentome of aborting dam. On immunohistochemistry, many bradyzoites and tachyzoites showing the N. cannium specific antibody positive reaction were observed in the tissue cyst and necrotized fetal placenta of the placentome of aborting dam. Electron microscopy showed that the wall of tissue cyst had a thickness of approximately 1 μm with an irregular shape. On the interior side, more than 100 bradyzoites with a length of 2-5 μm and width of 1-2 μm were observed. The nucleus of bradyzoite was located approximately 1-1.5 μm anterior to the posterior tip of the zoite. The many amylopectin granules, electron-dense small-sized and electron-thin large-sized round granules, homogeneously electron-dense rhoptries and micron- emes oriented perpendicularly to the zoite pellicle were obser- ved in the cytoplasm between the nucleus and the posterior tip. The six farms where the abortions had previously occurred demonstrated positive reactions to N. caninum. Although the mean Neospora-seropositive rate of six farms was 17.5%, the range of seropositivity was 3.4-57.1% due to the difference in seroprevalence between farms. The general pattern of seropositivity in cows was higher than in heifers. In addition, the abortion rate of Neospora-seropositive in 18 out of 32 pregnant dams raised in four farms was 16.7%. The seroprevalence of newborn calves from Neospora-seropositive pregnant animals differed according to the farm but was 86.7% overall. In contrast, 14 newborn calves from the Neospora-seronegative pregnant cattle showed Neospora- seronegative responses. The mean S/P value of Neospora-seropositive non-aborting animals (n=14) reached peak levels 15 weeks prior to parturition, and declined thereafter to parturition. The S/P value 13 weeks prior to abortion in Neospora-seropositive aborting cows (n=3) remained at high levels, and abortions occurred at 20 (142 days), 26 (185 days), and 28 weeks (199 days) after artificial insemination. IFN-γ levels in the Neospora- seropositive non-aborting group varied by individuals and gestational periods; IFN-γ levels stayed at elevated levels or increased abruptly close to abortion in Neospora-seropositive aborting cows. IFN-γ level patterns in the Neospora-serone- gative group (n=9) were similar to the Neospora-seropositive non-aborting group, although IFN-γ amounts were lower than the Neospora-seropositive group. The mean progesterone levels in the Neospora-seropositive non-aborting and Neospora-serone- gative groups decreased markedly 7 weeks prior to parturition. The mean progesterone levels 5 and 7 weeks prior to abortion were lower than the other groups 5 and 7 weeks prior to parturition. The mean 17β-estradiol levels in the Neospora- seropositve aborting cows increased close to abortion; the produced amounts were lower than those of Neospora- eropositve non-aborting and Neospora-seronegative groups close to parturition. Based on the above results, the tissue cyst in the brain which was from the aborted fetus from Neospora-seropositive dam by the ELISA was identified as N. caninum on immuno- histochemistry and electron microscopy. Besides, the N. caninum is endemic and the vertical transmission is responsible for the spread of infection from naturally N. caninum-infected dams to her offspring during pregnancy. And the lower levels of progesterone and 17β-estradiol in naturally N. caninum- infected cows may lead to increases in IFN-γ production and in turn may result in abortion.

주행저항 변화가 가솔린직접분사 차량과 디젤차량에서의 연비 상관성 및 배출가스 특성에 미치는 연구

손정훈 고려대학교 대학원 2016 국내석사

Vehicular emissions have an adverse impact on the global environment and human health. It is widely known that vehicular emissions lead to the global warming and air quality deterioration. So, the regulations of vehicular emissions have been tightened gradually. As part of the process, in the Europe, the driving cycle of the diesel vehicle for emission certification will be changed from the New European driving cycle (NEDC) to World-harmonized light-duty vehicle test cycle (WLTC) in 2017. Because WLTC is composed of four phases (low speed, medium speed, high speed, and extra-high speed) which reflects real driving conditions based on real-world vehicle journeys more than NEDC. Nowadays, it was revealed that there is a difference between emissions from type-approval (TA) test and those from Real-driving emissions (RDE) test. Accordingly, the RDE test, which might certify emissions in a wide range of operating conditions with portable emissions measurement systems (PEMS), will be instituted in future emission legislation. Especially, conformity factor (exhaust gas emissions in RDE / exhaust gas emissions in the type approval test) will be the important value in the forthcoming emission legislation. With regard to gasoline direct injection (GDI) engine, particle number (PN) has emerged as a problem in contrast with multi port injection (MPI) engine. Thus, gasoline particulate filter (GPF) may be applied in GDI vehicles in order to reduce particle mass (PM) and PN in the future. Also, reducing NOx emissions is the most important challenge in passenger cars. To satisfy the Euro 6 regulation, selective catalytic reduction (SCR), lean NOx Trap (LNT) and 2-stage exhaust gas recirculation (EGR) have begun to be applied to diesel passenger cars. The carbon dioxide (CO2) emissions and fuel-economy are important issues irrespective of the type of engine. However, the CO2 emissions and fuel-economy is affected by the driving resistances of a moving vehicle, such as rolling resistance and aerodynamic drag. As the current regulation related with the road loads involves the high tolerances and systematic errors, it is necessary to devise a method how to determine the road loads using coastdown runs. Previous researchs have revealed that the CO2 emissions increased reasonably due to the application of realistic road loads instead of the official EU road loads. Test flexibilities such as tire pressure, adjustment of brakes, vehicle preconditioning, test mass and running-in period are multiple factors for the vehicle emissions and fuel economy (FE) tests. The determination of road load (RL) force is the most influential flexibility factor for a TA vehicle certification test. Because of these various factors, it was revealed that there was a substantial difference between emissions from TA values and those from RDE test. In this study, test cycle RL energy using the RL coefficients determined by TA coastdown procedure was the base condition. After calculating the test cycle RL power, the constant term of the RL coefficient was changed by energy loss. The tolerance of the RL in domestic regulation is 15%. So the constant term of the RL coefficient was increased by 5% unit in the cycle RL energy loss. And then, RL power and tractive power were calculated by force and vehicle speed. The vehicle fuel efficiency, under RL variation conditions, was carried out with a modern 2.4 L GDI and LNT equipped diesel vehicle on the chassis dynamometer. To assess the impact of different RL values on FE and the CO2 emissions, the test cycle was performed over the combined mode of the federal test procedure (FTP-75) and the highway fuel economy test (HWFET) mode. To investigate the road-load variations by energy difference on the correlation of the vehicle FE, the statistical approaches of the one-way analysis of variance (ANOVA) were applied. Results showed that variations of the RL energy of the tested cycle were closely related with trade-off relationship with the vehicle FE.