1,721,084 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
A study on scheduling of power generation sources based on operators risk propensity in preparation for Microgrid island operations
No full text학위논문(석사) -- 서울대학교대학원 : 공학전문대학원 응용공학과, 2022.2. 윤용태.As major countries officially committed to being carbon neutral by 2050, discussions on carbon neutrality have been growing all around the world. As the electricity supply from renewable energy is expanded due to the electrification of energy, distributed energy resources such as solar power generation and energy storage system in the power distribution system unit is expected to increase steeply. However, controlling many distributed energy resources increases the burden on grid operators to operate the power system stably and efficiently. Accordingly, microgrid was introduced to solve the emergence of many distributed energy resources in the distribution system and to create a smart power grid. By controlling distributed energy, it allows to reduce the burden of system operators on the control of power grid and to manage the grid more efficiently
Typically, microgrid operators determine the optimal operation by interacting with the main grid, including maintaining a connection with the main grid, and supplying electricity to or receiving electricity from the market. In addition, as the power market is formed and the area is expanded to the market for auxiliary services such as frequency adjustment, the role of microgrid operators in many microgrid environments is expected to increase. Accordingly, in deriving an operation plan for optimal market participation, microgrid operators must consider risk factors: i.e., uncertainty of power load due to abnormal weather, and intermittent output characteristics of variable renewable energy such as solar power. It is important for microgrid operators to establish strategies to reduce risk factors: especially, they should efficiently establish their own operation plans with power plants and adjust the load usage schedule. This is because, when microgrid island operation occurs, the microgrid must bear the demand only with its own power source and, if necessary, it must cut off the load. In addition, uncertainty analysis on the possibility of future risk differs depending on the operator's risk propensity, the resultant operating schedule, and expected return will vary accordingly. Therefore, it is necessary for the microgrid operator to receive information on the operation schedule and expected return that are tailored to their risk inclinations considering the given reserve conditions and environment
In this thesis report, I propose a modeling method to obtain a daily power generation schedule that matches the risk propensity of the operator considering the risk factors that may occur in the microgrid island operation with the main grid. To this end, I assumed a rule that power transactions with the main grid are suspended when the reserve band set as the power supply and demand deviation exceeds the allowed limit under the premise of the PXFC (Power Exchange for Frequency Control) market, where market participants are obliged to secure reserve capacity according to the principle of cost-causing costs. Accordingly, the risk standard of microgrid operators was defined as the condition of maintaining their reserve power generation capacity so as not to exceed the reserve band. To minimize the daily operation costs according to the risk propensity of the microgrid operator, the scheduling for each time period of the power source, such as start-up, stop, or ESS charging/discharging, was modeled.
The proposed model was evaluated through simulation using Python. In addition, the method was proposed to determine how to efficiently operate one's own power generation resources by comparing the microgrid operation schedule method and the expected cost in accordance with the risk propensity of the operator.주요국에서 2050년 탄소중립 목표를 공식 선언하며 전 세계적으로 탄소중립 논의가 확산되고 있다. 에너지의 전기화로 재생에너지 중심으로 전력공급이 확대됨에 따라 배전시스템 단위에서의 태양광 발전, 에너지저장장치 등 분산에너지가 더 가파르게 증가할 전망이다. 그러나 많은 수의 분산에너지를 제어하는 것은 계통운영자가 전력 시스템을 안정적이고 효율적으로 운영하는 데 있어 부담이 가중된다. 이에 마이크로그리드는 배전시스템에서 다수의 분산에너지 출현을 해결하고 스마트한 전력망을 만들기 위해 도입되었으며, 분산에너지를 조정하여 계통운영자의 제어를 위한 부담을 줄이고 보다 효율적인 운영을 가능하게 한다.
일반적으로 마이크로그리드 운영자는 메인 그리드와 연결을 유지하고 전기를 공급하거나 시장에서 전기를 받는 등 메인 그리드와의 상호 작용을 통해 최적의 운영을 결정한다. 또한, 전력시장이 형성되고 주파수 조정과 같은 보조서비스 시장으로 영역이 확대됨에 따라 다수의 마이크로그리드 환경에서 마이크로그리드 운영자의 역할은 더욱 커질 것으로 예상한다. 이에 마이크로그리드 운영자는 최적의 시장참여를 위한 운영 방안을 도출함에 있어, 이상기후 발생에 따른 전력 부하의 불확실성과 태양광 등 가변재생에너지의 간헐적인 출력 특성 등 위험요인을 고려해야 한다. 메인 그리드와 거래중단이 발생할 경우 마이크로그리드는 자체 발전원으로만 수요를 부담해야 하며, 필요시 부하차단을 시행해야 할 수도 있기에 마이크로그리드 운영자는 자신의 발전원 운영 계획을 효율적으로 수립하거나 부하 사용 일정을 조정하는 등 위험요인을 감소시키는 전략을 세우는 것이 중요하다. 또한 미래의 위험요인이 발생할 확률에 대한 불확실성 분석은 운영자의 리스크 성향에 따라 다르며 그에 따라 결정되는 운영 스케쥴과 기대수익률은 변화하게 된다. 따라서 마이크로그리드 운영자는 주어진 예비력 여건 및 환경을 고려하여 자신의 리스크 성향에 맞춘 운영 스케쥴 방법과 기대수익률 정보를 받는 것이 필요하다.
본 연구보고서에서는 마이크로그리드가 메인 그리드와 전력거래가 중단됨에 따라 발생되는 위험요인을 고려하여 운영자의 리스크 성향에 맞는 일간 발전원 운영 스케쥴을 구하는 모델링을 제안하였다. 이를 위해 비용 유발자 부담 원칙에 따라 시장 참여자에게 예비력 확보 의무가 부여되는 PXFC (Power Exchange for Frequency Control) 시장을 전제하에 전력수급 편차로 설정한 예비력 밴드 위반 시 메인 그리드와 전력거래가 중단되는 규칙을 가정하였다. 이에 따라 예비력 밴드를 위반하지 않기 위한 자신의 예비 발전용량 유지조건을 위험성향 기준으로 정의하고 마이크로그리드 운영자 성향별 일간 운영비용 최소화를 목적으로 발전원의 시간대별 기동, 정지 또는 ESS 충방전 등에 대한 스케쥴링을 모델링하였다.
제안된 모델링은 파이썬을 활용한 시뮬레이션을 통해 검증하였으며, 운영자 성향에 따른 마이크로그리드 운영 스케쥴 방법과 기대비용을 비교하여, 자신의 발전자원을 어떤 방식으로 효율적으로 운영할 것인지를 결정하는 방안을 제시하였다.제1장 서 론 1
제1절 연구 배경 및 목적 1
제2절 연구보고서의 개요 및 구성 6
제2장 마이크로그리드 전력시장 7
제1절 마이크로그리드 역할과 기능 7
제2절 PXFC 시장 9
제3절 마이크로그리드 스케쥴링 구성요소 11
제3장 운영자 리스크 성향에 따른 마이크로그리드 발전원 스케쥴링 모델링 13
제1절 목적함수 13
제2절 제약조건 15
제4장 사례연구 25
제1절 시뮬레이션 조건 25
제2절 운영자 리스크 성향별 발전원 스케쥴 비교 30
제5장 결 론 35
참고문헌 37
Abstract 40석
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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