1,720,957 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
Optimal process design of re-liquefaction systems for LNG carrier
Get PDF학위논문(박사) -- 서울대학교대학원 : 공과대학 조선해양공학과, 2022.2. 임영섭.Due to tighter environmental regulations, the demand for liquefied natural gas (LNG) is continuously growing. The natural gas carrier does not require a separate fuel storage tank since it can use naturally generated BOG (boil-off gas) as fuel. However, the challenging issue for using BOG as fuel is to handle the surplus BOG. Unlike previous engines that incinerate surplus BOG through a gas combustion unit (GCU), the development of gas injection engines is changing the approach to BOG treatment of natural gas carriers. As a compressor capable of high-pressure compression is installed inside the fuel supply system, the boil-off gas can be recovered to the storage tank through the re-liquefaction process only by adding some equipment such as a heat exchanger and a phase separator. Through re-liquefaction process, it is possible to obtain economic profits by minimizing the loss of cargo, and also to reduce the amount of carbon dioxide emitted through GCU. Due to these advantages, studies on the re-liquefaction process of natural gas carriers are being conducted, but studies on designs that comprehensively consider process performance, economic feasibility, and environmental impact are still lacking.
In this paper, energy efficiency, economic feasibility, and environmental impact are analyzed by subdividing the fuel supply system and re-liquefaction process of LNG carrier according to their types. The fuel supply system is divided into a high-pressure gas injection engine and a low-pressure gas injection engine according to the operating pressure of the fuel. In case of high-pressure gas injection engine, this paper investigates the economic feasibility of the additional BOG liquefaction facilities in the high-pressure fuel supply system on the vessels. To utilize the existing BOG compressor for fuel production, the liquefaction was conducted by the Joule Thomson (JT) cycle, which can use the pres- surized BOG as a working fluid. For the comparison of the fuel supply system and its variations with BOG liquefaction, they are optimized with respect to total annual cost (TAC) as the objective function. With an LNG price of 5 USD/MMBtu, the optimization results show that the use of BOG liquefiers on LNG vessels reduces the TAC by at least 9.4% compared to the high pressure fuel supply system. The use of a liquid turbine in the liquefaction configurations also resulted in 2.4% savings in TAC compared to the JT cycle based process. However, a sensitivity analysis with different LNG prices indicates that the liquefaction systems are not economical compared to the fuel supply system when the LNG price is lower than 4 USD/ MMBtu.
In case of low-pressure gas injection engine, this paper performs a comparative analysis in terms of efficiency by simplifying the composition of the mixed refrigerant in the liquefaction pro- cess. Additionally, a single mixed refrigerant process is used to pursue the compactness of the pro- cess. For comparative analysis, the liquefaction process is designed and simulated, and the specific power consumption calculated as the power required to liquefy the unit LNG is used as the objective function to optimize. As a result, it is confirmed that when the number of refrigerants is reduced from 5 to 4, the efficiency is only about a 1% difference, but when it is reduced to 3, the efficiency decreases by 23%, resulting in a decrease in performance. And also, this paper comparatively analyzes the re-liquefaction system for a low-pressure gas injection engine according to the refrigerant (no external refrigerant or single mixed refrigerant) with three key performance indicators: energetic, economic, and environmental aspects. For an energy efficiency analysis, the design is optimized to minimize the specific power consumption required to liquefy BOG. In economic analysis, minimizing total annualized cost is the objective. For an environmental analysis, CO2 emissions at each optimal point is calculated and comparatively analyzed. The results show that the process without external refrigerant has better performance in terms of economy, while the single mixed refrigerant process is suitable in terms of energy efficiency and environmental impact.선박의 배출가스 규제가 심해짐에 따라 천연가스는 최근 가장 각광받는 연료 중 하나이다. 천연가스 운반선의 경우 저장탱크 내부에서 자연발생하는 증발가스 (BOG, Boil-off gas) 를 연료로 사용할 수 있어서 별도의 저장 설비가 필요 없다는 장점이 있지만, 연료로 사용하고 남은 증발가스를 처리해야하는 문제가 있다. 가스 소각 시스템 (GCU, Gas combustion unit) 을 통해 남은 증발가스를 처리했던 과거의 엔진들과는 달리, 가스 분사 엔진이 개발되면서 천연가스 운반선의 증발가스 처리에 대한 접근도 달라지고 있다. 추진 시스템 내부에 고압 압축이 가능한 압축기가 설치되면서, 열교환기 및 상 분리기 등의 몇 가지 장비의 추가 만으로도 재액화 공정을 통해 증발가스를 저장탱크로 회수할 수 있다. 이 과정을 통해 상품의 손실을 최소화 하여 경제적 이득을 취할 수 있을 뿐더러, 가스 소각 시스템을 통해 배출되는 이산화탄소의 양까지 줄일 수 있다. 이러한 장점들로 인해 천연가스 운반선의 재액화 공정에 대한 연구가 이루어지고 있지만, 공정 성능과 경제성, 나아가 환경적 영향을 종합적으로 고려한 설계에 대한 연구는 아직 부족하다.
본 논문에서는 선박의 연료 공급 시스템과 재액화 공정을 종류에 따라 세분화 하여 에너지 효율, 경제성 및 환경적 영향을 분석했다. 연료 공급 시스템은 연료의 작동 압력에 따라 고압 가스 분사 엔진, 저압 가스 분사 엔진으로 구분했다. 재액화 공정의 경우 냉매에 따라 자가 재액화 공정, 단일 혼합 냉매 공정으로 구분했다. 고압 가스 분사 엔진의 경우 재액화 공정의 비용을 추산하였고, 추진 시스템과의 (즉, 재액화 공정이 탑재되지 않은 천연가스 운반선의 추진 시스템) 비교를 통해 연간 비용을 얼마나 줄일 수 있는지를 평가했다. 추진 시스템 내부에 탑재된 압축기를 활용하여 압축된 증발가스를 작동 유체로 하는 줄-톰슨 사이클을 적용하여 공정을 설계했으며 다양한 설계안을 고려해 비용 절감을 최대화 할 수 있는 방법을 모색했다. 천연가스의 가격이 4/MMBTU 미만인 경우 재액화 시스템을 통해 경제적 이득을 얻기가 어려움을 확인했다.
저압 가스 분사 엔진이 최근 추진 시스템의 또 다른 옵션으로 떠오르면서 이를 접목한 재액화 공정의 최적 설계를 진행했다. 저압 가스 분사 엔진의 경우 증발가스의 압축 압력이 16 bar 정도로 고압 엔진의 압력 (300 bar) 에 비해 현저히 낮기에, 추진 시스템 내부의 압축기 만으로는 공정을 구성하는 데 어려움이 있다. 따라서 재액화 공정을 위해서는 추가 압축기가 필요하며, 이는 곧 자가 재액화 뿐만 아니라 외부 냉매를 사용한 공정 역시 고려 대상이 될 수 있음을 의미한다. 본 연구에서는 단일 혼합 냉매 공정을 적용하여 재액화 공정을 설계 했으며, 단일 혼합 냉매 공정의 조성 최적화를 통해 조성의 개수를 줄여 공정의 단순화를 추구했을 시 성능의 변화를 분석하였다. 그 결과 혼합 냉매의 조성을 질소, 메탄, 에탄, 부탄의 4개로 구성했을 시 약 1 % 정도의 성능 차이를 보였고, 3개로 구성했을 시에는 23 % 정도의 효율 저하가 생김을 확인하여 냉매 조성의 단순화는 4개가 한계임을 확인했다. 또한 저압 가스 분사 엔진의 재액화 공정을 에너지 효율, 경제성, 환경의 3 가지 측면에서 냉매의 유무에 따라 (자가 재액화 공정, 단일 혼합 냉매 공정) 비교 분석을 수행했다. 에너지 효율 분석을 위해 단위 천연가스를 액화 하는데 필요한 전력량을 최소화하는 설계안을 찾았다. 경제성 분석은 총 연간 비용을 최소화 하기 위한 최적점을 찾았다. 환경 분석을 위해 각 설계 최적점에서의 이산화 탄소 배출량을 계산하여 비교 분석을 수행했다. 그 결과 자가 재액화 공정이 경제성 측면에서 더 나은 성능을 보인 반면, 단일 혼합 냉매 액화 공정이 에너지 효율 및 환경 영향 측면에서 좀 더 적합하다는 것을 확인했다.1. 서론 1
2. 연료공급시스템 및 재액화공정 9
3. 시스템 평가 지표 19
4. 재액화 공정 평가 28
5. 결론 87
영문초록 98박
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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