DC 모터의 속도제어를 위한 모델기반 퍼이제어기 설계

김병만 한국해양대학교 대학원 2001 국내석사

시간영역에서의 양단자 정보를 이용한 송전선로 아크 사고 거리 추정

김병만 전북대학교 대학원 2010 국내박사

The occurrence of a fault on a transmission line could cause a lot of economical losses and social problems. A rapid fault restoration of the transmission line is essential for enhancing the quality of electricity. As outage time increases more and more, transmission company would pay more loss of revenue and credit. Thus, when a fault occurs in the transmission line system, a transmission grid company tries to restore the faulted transmission line as quickly possible to provide the service continuity to the customers and minimize the outage cost due to late restoration. Therefore, accurate fault location is essential for rapid restoration. Many accurate fault location algorithms have been suggested. However, these algorithms are effective only for a linear fault as they are developed in the frequency domain. The fault location in the case of an arc fault is necessary. This dissertation presents a numerical algorithm for arc fault location of a transmission line in the time domain. The proposed algorithm is based on the synchronized voltages and currents measured at both local and remote ends. This dissertation proposes two arc fault location algorithms for short and long transmission lines, respectively. The former does not include the parallel capacitance while the latter does. The proposed location algorithms are derived from the voltage equations at the local and remote ends. They are composed of location algorithms for phase-to-ground fault and line-to-line fault, respectively. Each algorithm is divided into the short and long lines. To test the validity of the proposed algorithms, the test results of the algorithm under various fault conditions are shown using an EMTP/ATP simulator. The results indicate that the proposed algorithm can accurately calculate the fault distance of a transmission line.

환경영향평가의 자연생태환경분야 개선방안에 관한 연구 : 도로의 건설사업을 중심으로

김병만 광운대학교 대학원 2017 국내석사

환경영향평가제도의 지속적인 발전에도 불구하고 아직까지 일부 사업에서 부실평가 등으로 환경영향평가의 실효성 논란이 제기되고 있다. 특히, 자연생태환경분야는 그러한 논란의 중심으로 자리잡고 있어 환경영향평가의 신뢰성 회복을 위해서는 자연생태환경분야의 내실화 증대 등의 개선대 책이 요구된다. 이에, 최근 10년간 협의완료된 "도로의 건설사업" 환경영향평가서 중 자연생태환경분야(동·식물상)를 대상으로 문제점 및 개선방안에 대해 고찰하 였다. 본구의 결과를 요약하면 다음과 같다. 주요 문제점으로는 첫째, 일부 미비한 현황조사, 둘째, 정성적 영향 예측 위주의 한계, 셋째, 저감대책의 효율성 부족, 넷째 사후환경영향조사 계획의 구체성 결여 등의 문제점이 도출되었다. 이에 대한 개선방안으로는 첫째, 전문성 확보를 통한 조사방법의 개선, 둘째, 정량적 예측·평가기법의 개발 및 적용, 셋째, 합리적 저감대책의 수립, 넷째, 사후환경영향조사 조사방법론 개선 등의 개선방안이 요구된다. 앞서 도출된 문제점과 개선방안의 적용을 통해 자연생태환경분야의 보다 내실있는 현장조사, 과학적이고 합리적인 영향예측, 실제 현장에 적합한 저감 대책의 마련과 더불어 충실한 사후환경영향조사 계획의 수립을 통한 환경영향 평가제도의 내실화 증대 및 신뢰성 회복에 기여할 수 있길 바라는 바이다. Despite the continuous improvement of the environmental impact assessment system, there has been controversy over the effectiveness of the environmental impact assessment due to poor evaluation in some projects. In particular, the field of natural and ecological environment is at the center of such controversy, and in order to restore the credibility of the environmental impact assessment, measures for improvement such as improvement of the natural ecological environment field are required. Therefore, the problems and the improvement plan for the natural ecological environment field of the "road construction project" environmental impact assessment report which has been consulted for the last 10 years were examined. The results of this study are summarized as follows. The main problems are as follows: First, some inadequate field surveys; second, limitations of qualitative impact prediction; third, lack of effectiveness of mitigation measures; and lack of specificization of fourth monitoring. As an improvement measure, First, improvement of survey method through securing expertise, second, development and application of quantitative prediction and evaluation technique, third, establish a reasonable mitigation plan, and fourth, improvement of monitoring survey method are required. Through the application of the above-mentioned problems and improvement measures, it is possible to conduct more effective field surveys in the field of natural and ecological environment, to predict scientific and reasonable impacts, to establish appropriate mitigation measures and to establish adequate monitoring plans. I hope that it will contribute to the enhancement of the environmental impact assessment system and the restoration of credibility.

DC 모터의 속도제어를 위한 모델기반 퍼지제어기 설계

김병만 한국해양대학교 대학원 2001 국내석사

In this paper, a methodology for designing a controller based on inverse dynamics for speed control of DC motors is presented. The proposed controller has robustness in disturbance and it consists of a prefilter, the inverse dynamic model of a system and a fuzzy logic controller. The prefilter prevents high frequency effects from the inverse dynamic model. The model of the system is characterized by a nonlinear equation with coulomb friction and viscous friction. The fuzzy logic controller(FLC) is characterized by fuzzy "If-then" rules which represent locally linear control output whose consequence part is defined as linear PI controllers. And it regulates the error between the set-point and the system output which may be caused by disturbances and it simultaneously traces the change of the reference input. A real coded genetic algorithm estimates the parameters of both the model and the linear PI controller. And it is characterized by three basic genetic operators that can deal with real coding chromosomes. An experimental work on a DC motor system is carried out to illustrate the performance of the proposed controller.

MPPT 제어 시스템 구현을 위한 Hardware-In-the-Loop 시뮬레이션 적용

김병만 광운대학교 2005 국내석사

최근 전기⋅전자 분야에서 초기 연구 개발기간을 단축시키고, 개발비용을 줄이는 것이 기업의 경쟁력이라 말할 수 있다. 이러한 현실에서 우리나라에서는 단지 해당 실무자의 능력 및 성실성만을 의존해 개발기간 단축에 중점을 두고 있는 것이 현실이다. 이와는 대조적으로 선진국의 경우, 연구개발에서 시행착오를 최소화할 수 있는 시스템 개발방법에 중점을 두고 있으며, 이러한 연구는 여러 분야에서 진행되어지고 있다. 이에 본 논문에서는 선진국의 시스템 개발 방법 중의 하나인 HIL(hardware-in-the-loop) 시뮬레이션 방법을 적용하여 제어기(controller)는 TMS320F2812 DSP(digital signal processer)를 이용하여 설계하였고, 제어대상(process)은 VisSim/ECD로 모델링하여 햇빛발전시스템(PV PCS : photovoltaic power conditioning system)에 반드시 적용되어지는 MPPT(maximum power point tracking)제어 시스템을 구현함으로서 연구개발 초기의 투자비용을 줄일 수 있고, 개발 소요시간을 단축시킬 수 있다는 것을 검증하였다. Recently, in the field of electrical and electronic engineering, it's said that competitive power of enterprise has cut down development expenses and development period. In this circumstance, it is to be regretted that we emphasize reduction of time for development depending on the developer's ability and sincerity. On the other hand, most of the developed countries emphasize and progress the system improvement to minimize trial and error in various fields. In this paper, the research performed by applied HIL(hardware-in-the-loop) simulation method and used TMS320F2812 DSP with the controller and the model made by VisSim/ECD with the process realizes MPPT(maximum power point tracking) control system for PV PCS(photovoltaic power conditioning system), therefore It is proved that the research can decrease investment expenses and reduce development time.

순천만 수질환경 특성에 관한 연구

김병만 순천대학교 대학원 2009 국내석사

순천만 해수의 화학적 특성을 파악하기 위하여 총 15개 정점과 육상오염원인 하천 6개 정점에서 채취한 시료를 대상으로 수질항목에 대하여 조사 결과와 고찰을 통하여 다음과 같은 결론에 도달하였다. 1) 염분은 5월과 12월에 각각 5.80-30.55psu(평균 20.01psu), 18.03-30.42psu(평균 26.71psu), COD는 각각 1.31-3.11mg/L(평균 2.27mg/L), 1.37-2.81mg/L(평균 1.99mg/L), DIN은 각각 24.37-408.30μM/L(평균 148.68μM/L), 25.3-215.11μM/L(평균 77.56μM/L), DIP는 각각 0.43-11.21μM/L(평균 3.08μM/L), 1.72-12.95μM/L(평균 4.56μM/L), TN은 각각 1.47-6.45mg/L(평균 2.91mg/L), 1.31-4.92mg/L(평균 2.31mg/L), TP는 각각 0.09-0.39mg/L(평균 0.19mg/L), 0.11-0.47mg/L(평균 0.25mg/L)의 분포를 보였으며, 염분농도가 낮은 만입부에서 고농도를 보였으며 염분농도가 높은 만하부로 내려갈수록 농도가 낮아졌다. 육상오염원인 담수의 유입이 영양염농도 변화에 영향을 미치는 것 같다. 2) 과잉용존무기질소를 산정한 결과 대부분 양(+)의 값을 보여 인이 제한물질로 나타났다. 3) Okaichi 等 (1973) 이 제안한 부영양화도에 의하여 계산된 결과 염분농도가 낮은 만입부에서 높은 농도를 나타냈고 염분농도가 높은 만하부에서 낮은 농도를 나타냈다. 염분과 음(-)의 상관관계가 나타난 걸로 볼떄 육상오염원인 담수의 유입이 농도변화에 영향을 미치는 것 같다. 4) SPSS에 의한 상관분석 결과 염분은 COD(r=0.77, p<0.01), DIP(r=0.46, p=0.001), DIN(r=0.90, p<0.001), Si(r=0.91, p<0.001), TN(r=0.81, p<0.001), TP(r=0.75, p<0.001)와는 음의 상관을 보였다. PCA(principle component analysis) 분석 결과 순천만내의 수질은 염분이 기타 수질항목을 조절하는 주요 요인으로 나타났다. 5) 순천만에 유입되는 6개하천의 각각의 영양염의 평균농도는 쌍림천, 이사천, 동천, 종말처리장, 해룡천, 두봉천 순으로 보면 COD는 2.66mg/L, 1.93mg/L, 2.51mg/L, 4.18mg/L, 3.68mg/L, 2.75mg/L로 나타났고 DIN의 농도는 91.39μM/L, 91.87μM/L, 482.17μM/L, 817.37μM/L, 252.12μM/L, 102.57μM/L로 나타났다. DIP의 농도는 1.22μM/L, 0.73μM/L, 10.13μM/L, 11.60μM/L, 4.70μM/L, 1.55μM/L로 나타났다. 6) 순천만에 유입되는 육상오염원의 영양염 전체농도는 순천시 하수 종말처리장과 동천의 DIN과 DIP농도가 전체의 조사정점중 가장 높은 농도를 나타났다. 순천만의 육상오염원인 담수의 유입으로 오염된다고 했을 때 종말처리장과 동천의 영향이 가장 클 것이라고 생각된다. 7) 순천만의 장기적인 오염도을 줄이기 위해서는 종말처리장과 동천의 유입수의 지속적인 수질관리가 필요하다고 생각된다. According to the survey of Suncheon Bay, COD, DIN, DIP, SiO2-Si, TN, TP which are the index of the water pollution are measured as high concentration at the beginning of estuary and getting lower concentration goes to the end of estuary. It is the typical characteristic of the estuary. As quoted results of correlation analysis of SPSS and PCA, salinity was revealed as a main factor of control for water qualities at sampling sites in Suncheon bay. Besides, the Excess DIN and the eutrophic degree in Suncheon Bay are high concectration at the beginning of estuary where the salinity is low but low concentration at the end of estuary where the salinity is high. We found out that phosphorus is the limit substance because Excess DIN shows almost positive. As the measurement of the nutrient and water pollution ratio in the six rivers which are inflowed into Suncheon Bay, Dong River and Suncheon Sewage Disposal Plant are the biggest influencing on the pollution in Suncheon Bay.

사립유치원 원장의 유치원 운영관리에 대한 직무스트레스 인식 및 해결방안

김병만 부산대학교 2009 국내석사

This study aims to recognize work-related stress and come up with solutions about what private-kindergarten directors do their job in their own management. Through this process, it identifies difficulties of director's management and provides adequate ways to deal with the situation. The research questions for the purpose of this study are as followed: First, What are the aspects of work-related stress about directors' management? Second, What are solutions to handle the situation? The respondents for this study are 200 kindergarten directors in Busan, Ulsan and Gyoung-Nam province. 162 copies are finally analized in statistics. The survey is consisted of total 120 items: 75 questions about work-related stress and 45 about measures to cope with the situation. The research results and consequences are summarized into two main categories. First, directors feel the stress in budget, duties of teachers and their work. After identifying differences of personal stress, there is the significant difference in the age of directors and directors' career(p<.01) while there is no significant difference in teachers' education level and teachers' career in statistics. After identifying differences of stress in working environment, there is the significant difference in the way directors own the kindergarten(p<.05) and whether or not a master stay at kindergarten(p<.001) while there is no significant difference in how many classroom at the kindergarten. Second, in terms of solutions of job stress about directors' management, it is the best way to address this difficulties psychologically, directly and mentaly. Through this process, there is the significant difference stemming from the age of directors(p<.01) while there is no significant difference in the education level, teachers' career and management career in statistics. After identifying solutions of job stress about working environment, there is no significant difference in the way directors own the kindergarten, how many classroom at the kindergarten and whether or not a master stay at kindergarten. The measures about work-related stress which directors are pursuing are divided into personal, professional, recognizable and political solutions. Personal solution to solve this problem can be classified and applied through diverse experience, as a multiplayer director, and consumer centered management of kindergarten. Professional solution can be classified and applied through improvement of director’s educational expertise and leadership of director. Recognizable solution can be classified and applied through conversion of social awareness, democratic community relationship, and both sided assessment of kindergarten. Lastly, political solution can be classified and applied through enrichment of government’s support of private kindergarten, actual improvement of policy, and unification of education and nurture.

단편영화 <8만원> 제작보고서 : 연출을 중심으로

김병만 중앙대학교 첨단영상대학원 2013 국내석사

본 제작보고서는 2011년 6월부터 2012년 3월까지 제작된 단편 극영화 <8만원 (80,000Won)>의 제작과정을 담았다. 영화 <8만원>은 연미라는 캐릭터가 하는 선택 과 그를 둘러싼 배경을 중심으로 사회구조적인 문제를 담아내고자 한 사회극이다. 본 보고서의 구성은 일반적인 영화제작 과정의 틀을 중심으로 프리-프로덕션(Pre-Production) → 프로덕션(Production) → 포스트-프로덕션(Post-Production)의 작업과정을 세밀하게 기술하였다. 프리-프로덕션(Pre-Production)의 과정에서는 영화의 시나리오 작성과 영화의 설정을 중심으로 기술되었으며 제작도구 및 설정, 로케이션에 대한 내용을 중심으로 기술되었다. 프로덕션(Production)과정은 연출과정을 중심으로 기술하였으며 돌발적인 상황이나 임기응변형의 대처에 관하여서도 기록하였다. 포스트-프로덕션(Post-Production)에서는 CG 및 음악작업을 주로 기술하였다. 영화 <8만원>은 ‘연미’라는 주인공의 성장드라마이면서 사회극이다. 연출자(필자)는 제작의 전 과정에서 사회와 세대에 관한 우리사회의 담론에 주시하였고 이를 영화에 반영하고자 노력하였다. 또한 촬영, 미술팀과의 대화를 통하여 척박한 사회를 반영할 수 있는 영화의 톤과 매너 그리고 앵글에 대하여 의견교환을 하였다. 그 외의 스태프들도 자신의 목소리를 연출자와 이야기 하며 영화의 완성도를 높이는 데 주요한 모니터를 제공하였다. 의견교환과 모니터를 통하여 영화에 대한 이해가 높은 스태프들과 작업을 할 수 있었다. 본 제작보고서를 작성함에 있어 중점을 둔 것은 연출과정에서 저예산 독립영화가 가질 수 있는 한계에서부터 이를 극복해 나가는 과정을 객관적으로 다루는 것 이었다. 따라서 로케이션의 섭외 후 실패의 경험이나 포스트-프로덕션을 통한 오류 수정과정 등 실패와 이를 극복한 경험을 모두 담고 있다. 본 보고서를 통하여 저예산으로 독립단편영화를 제작하려는 동료들에게 도움을 주고자 하는 바람으로 돌아보면 부끄러운 실수들도 자기반성의 의미에서 담아 두었다. This production report is about the directing process of short film <80,000Won> which was made from June, 2011 to March, 2012. The social life drama <80,000 Won> is trying to carry a social structural issue via the main character 'Yun-mi's choice and the background of her behaviors. This report describes the directing process in the order of 'Pre-Production, Production, Post-Production' in detail and the flow follows the general film-making process. In the Pre-Production part, it mainly describes how to start creating the scenario and set its background. Also, explanation on production tools, set-up and location is included. In the Production part, it focuses on the directing process and how to handle incidents and improvise on emergent situations. Lastly, in the Post-Production part, it mainly explains about CG and music operation. The short film <80,000 Won> is a 'social life' genre and main character 'Yun-mi's growth' drama. The writer pays attention and reflects on the film about current social discussion, 'Society and Generation'. All through the directing stage, the writer exchanges opinions about tone & manner and camera angles with Camera team and Art team to carry the current old-hearted social atmosphere. The other staffs also proactively interact to make a qualitative film. The close cooperation and frequent discussion with all staffs contributes to get comprehensive understanding of the essentials. This report mainly focuses on how to overcome limitation of low-budget film in the process of directing with objective perspective. Therefore, it includes all the experiences including failure, challenge, and success such as location hunting, error correction during the Post-Production. The writer also tries to include even shameful mistakes as self-reflection and to give a help to all co-workers who are willing to make a low-budget independent film.

유아교육정책 평가준거 개발

김병만 부산대학교 대학원 2014 국내박사

The purpose of this study was to examine the systematic classification and evaluation standard of early childhood education policies based on theories of early childhood education policy evaluation and the opinions of experts in an effort to develop early childhood evaluation policy evaluation criteria. The early childhood education evaluation criteria developed in this study are expected to make it possible to accurately evaluate early childhood education policies executed in this field and to offer useful feedback. It's specifically meant to develop criteria available for early childhood education policy evaluation based on the views of experts in early childhood policy and evaluation, in early childhood education administration and in early childhood education and of kindergarten teachers, and to validate the developed evaluation criteria by testing their relative importance and usability. To serve the purpose of the study, the following efforts were made: 1. Develop early childhood education policy evaluation criteria. 2. Validate the early childhood education policy evaluation criteria developed in this study. The major findings of the study were as follows: First, literature related to early childhood education policy evaluation criteria were reviewed to determine the right directions for the development of the criteria, and a focus group interview was conducted twice after eight experts were selected. SWOT analysis and content analysis were made to analyze the opinions that the experts gave in the focus group interviews. Besides, a primary Delphi survey was conducted to check the opinions of other selected experts on the right directions for the development of early childhood education policy evaluation criteria. According to the results of SWOT analysis on the right directions for the development of early childhood education policy evaluation criteria, four categories were selected: strengths, weaknesses, opportunity and threat. When a SWOT matrix strategy analysis was made to formulate strategies for the development of the criteria, four strategies were suggested: 'satisfying the requirements of the times,' 'developing well-grounded criteria taking diverse theoretical perspectives,' 'addressing the needs of different members,' and 'developing sustainable, realistic and effective criteria.' And a content analysis of the focus group interview data was made to see whether the directions for early childhood education policy evaluation criteria would be right or not. The primary Delphi survey was conducted on a panel of 33 members who were experts in early childhood education policy and evaluation, in early childhood education administration and in early childhood education. Open-ended and closed-ended questions were both used. A primary draft of the evaluation criteria was drawn up based on the opinions of the panel members, which consisted of four evaluation categories, 14 evaluation criteria and 55 evaluation elements according to the framework of evaluation category-evaluation criteria-evaluation element. And then Delphi survey were conducted twice more on the panel of specialists. In the secondary Delphi survey, opinions were gathered from the panel about the primary draft of the evaluation criteria that was made based on the results of the primary Delphi survey. Their opinions on the representativeness, accuracy and comprehensiveness of the evaluation criteria, evaluation elements and evaluation indexes were analyzed. After questionnaires were handed out to 33 panel members, the answer sheets from 32 panel members were collected, and frequency analysis and descriptive statistics(mean, standard deviation, skewness and quartile) were utilized to analyze the collected data. Since the dominant opinion of the panel members was that the framework of evaluation category-evaluation criteria-evaluation index would be more adequate than the framework of evaluation criteria used in the primary Delphi survey, some of the terms were changed. When the appropriateness of the evaluation categories, evaluation criteria and evaluation indexes were analyzed, they gave a mean of less than four out of five in each index. The evaluation criteria and evaluation indexes to which less than four average marks were given out of five, which were positively skewed, or which the experts considered it necessary to modify were modified, and some of them were omitted or integrated. Thus, a secondary draft was drawn up, which consisted of 13 evaluation criteria and 44 evaluation elements. In the tertiary Delphi survey, questionnaires that were designed to check the results of the secondary survey and reach a consensus were utilized, and frequency analysis and descriptive statistics(mean, standard deviation, skewness and quartile) were utilized. After the opinions of the panel were analyzed about appropriateness, a final draft was drawn up, which consisted of four evaluation categories, 13 evaluation criteria and 44 evaluation indexes. Out of the evaluation criteria, two were modified in part according to the opinions of the panel. Second, AHP and usability analysis were conducted to check the validity of the early childhood education policy evaluation criteria. The 32 panel members who participated in the Delphi survey were asked to analyze weight by using AHP. The weight analysis method by AHP was composed of three-stage hierarchical structure, and each of the three stages respectively consisted of the four evaluation categories, 13 evaluation criteria and 44 evaluation indexes developed in this study. As a result of calculating the consistency ratio of the ratings of the individual panel members, the consistency ratio of the answers of 12 panel members out of 32 was above 0.1. So a second investigation was fulfilled by asking these panels whose consistency ratio was higher to rate once again. When the results of the first and second investigations were analyzed, the answers of 24 panel members whose average consistency ratio was below 0.1 were selected for final analysis. And then the simple weight of the evaluation categories, evaluation criteria and evaluation indexes was converted into percentage. As for the evaluation categories, early childhood education policy publicness was given the most weight(34.2%), followed by policy suitability(31.7%), policy democracy(23.1%) and policy economic efficiency(11.0%). Afterwards, the simple weight of the evaluation criteria and evaluation indexes was respectively calculated within the superordinate dimensions, namely the evaluation categories to which each of them belonged. As a result of analyzing the total weight of the evaluation criteria and evaluation indexes, public benefit(.150) was found to be top priority for the evaluation criteria, followed by feasibility(.118), accountability(.102) and sufficiency(.090). As for the evaluation indexes, top priority was given to the level of contribution to the interests of preschoolers(.063), followed by the level of fulfilling social obligation(.056) and the level of long-tern benefit(.053). In order to check whether the evaluation criteria developed in this study would be appropriate enough to assess early childhood education policies, 307 kindergarten teachers who served as early childhood teachers for three years or more were asked to assess the usability of the evaluation criteria and evaluation indexes. To be specific, their validity, reliability, response distribution for the evaluation indexes and the discrimination of the evaluation indexes were all checked. As for the validity of the evaluation criteria, their content validity and construct validity were checked. As a result of calculating mean scores about the importance of the evaluation indexes, the kindergarten teachers placed high value on all the 44 evaluation indexes. Their mean scores ranged between 3.99 and 4.30. So the evaluation indexes of the evaluation criteria turned out to be composed of significant items to assess early childhood education policies, and the content validity of the evaluation indexes were quite good. To check construct validity, the teachers rated the appropriateness of the evaluation criteria. When the correlation between the evaluation criteria and total scores and between the evaluation indexes and total scores was analyzed, total scores were closely correlated to every subarea and every item. Thus, it's confirmed that the evaluation criteria and evaluation indexes developed in this study were valid enough to make a valid assessment of early childhood education policies. When internal consistency was checked to confirm the reliability of the subordinate evaluation indexes of the evaluation criteria, Cronbach alpha coefficient stood at .97. As a result of analyzing split-half reliability, Spearman-Brown coefficient stood at .93. The findings showed that the evaluation criteria were stable criteria to make a consistent assessment of early childhood education policies. Regarding the usability of the evaluation indexes, the response distribution and discrimination of the evaluation indexes were analyzed. The response distribution was mostly negatively skewed, and the mean scores ranged from 3.85 to 4.14. Thus, none of the evaluation indexes were given extreme mean scores(M>4.50 or M<.50), and none of them had an extremely lower standard deviation(SD<.50), either. Therefore the evaluation indexes of the evaluation criteria were found to be appropriate for early childhood education policy evaluation. A group that was in the top 27 percent got higher mean scores in every evaluation index of the evaluation criteria than another group in the bottom 27 percent, and the differences between the two were statistically significant. Therefore the evaluation indexes of the evaluation criteria turned out to be excellent in discriminating between an upper-tiered group and a lower-tiered group. Thus, the evaluation criteria and evaluation indexes were identified as a valid and reliable scale to assess early childhood education policies, and were found to be composed of usable items that can make a systematic assessment of the characteristics of early childhood education policies.

Characteristic study on CdS/CdSe quantum dot-sensitized solar cells depending on counter electrode

김병만 부산대학교 2013 국내석사

양자점 감응형 태양전지에 요오드계 전해질의 대체물로써 가장 일반적인 polysulfide 전해질은 백금 (Pt)을 증착한 상대전극과 함께 사용될 수 없다. 그 이유는 polysulfide 전해질 내 황화물들이 백금과 같은 귀금속 물질에 화학적 흡착하여 쌓이게 되고 전자의 이동을 방해하기 때문이다. 이 현상을 억제하기 위해 황화납 (lead sulfide, PbS) 양자점을 포함한 여러 물질들을 SILAR 법을 이용하여 백금 상대전극에 증착한 후 백금 상대전극과 비교하였다. 전기화학적 및 광학적 분석을 통하여 황화납 양자점들이 증착 된 백금 상대전극은 polysulfide 전해질 내에서 우수한 전기화학적 촉매 특성을 보였으며 광전 효과에 의해 추가적인 광전자들을 제공하여 산화/환원 반응을 가속시켰다. 그 결과, 백금/황화납 양자점 상대전극을 이용해 제작한 셀은 백금 상대전극을 이용한 셀보다 83% 상승한 광전변환 효율 (2.85%)을 보였다.