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A Study on Fuzzy WEDM Process with Workpieces of Variant Height
No full text本文目的在於改善線切割放電加工機在切割工件厚度變化處之不穩定現象。文中先以實驗求得不同厚度與伺服電壓下之進給速率，設此進給速率為理想進給速率。再設計一模糊控制器，以間隙電壓、間隙電壓變化量與目前進給速率和理想進給速率之差距為控制器之輸入變數制定模糊控制法則，對厚度變化之瞬間制定控制策略，在加工時由控制器推論出適合之進給速率。
由實驗結果顯示，本文所設計之控制系統，可在經過工件段差時，推論出最適當的進給速率，大幅度穩定加工狀態與提升暫態性能。且進給速率在控制下皆未產生超越量(overshoot)或震盪，避免了因進給速率過度加速所造成之危機。加工過程中，進給速率在穩態時最大變動量約0.05mm/min。The purpose of this study is to overcome the instability occurring in the Wire-EDM process when the cutting wire is encountering the abrupt change of the height of the workpieces. An algorithm which is able to estimate the optimal feed rate automatically during the Wire-EDM process is proposed. A fuzzy controller with multiple control rules for different changing conditions of the height of the workpieces is designed. The most appropriate feed rate is calculated by the fuzzy controller according to the present gap voltage and the estimated workpiece height. Experiments have shown that sat factory performance is obtained with the assistance of the fuzzy controller. The Wire-EDM process becomes stably without overshoot and oscillation even when the height of the workpiece changes abruptly. The transient performance is also enhanced, and the maximum variation of feed rate in the steady state during the Wire-EDM process is 0.05mm/min.致謝...............................................................一
摘要...............................................................二
英文摘要...........................................................三
目錄...............................................................四
圖目錄.............................................................六
表目錄.............................................................九
符號說明...........................................................十
第一章 緒論........................................................ 1
1-1 引言........................................................1
1-2 文獻回顧....................................................2
1-3 研究目的與方法..............................................6
1-4 本文結構....................................................8
第二章 放電加工原理介紹............................................ 9
2-1 放電加工原理................................................9
2-2 放電基本轉換過程及火花結構.................................12
2-3 放電電源及波形.............................................14
2-4 線切割放電加工之特性.......................................18
第三章 模糊理論之介紹............................................. 21
3-1 模糊理論概述...............................................21
3-2 集合理論...................................................23
3-3 模糊控制器.................................................25
3-3.1 歸屬函數.............................................26
3-3.2 模糊分割.............................................27
3-3.3 模糊控制規則.........................................29
3-3.4 模糊推論.............................................29
3-3.5 解模糊化.............................................30
3-4 模糊控制之特點.............................................31
五
第四章 實驗設備與實驗規劃......................................... 32
4-1 實驗設備與材料.............................................32
4-2 伺服進給系統原理...........................................36
第五章 模糊控制器之研究........................................... 38
5-1 不同厚度與相異間隙電壓下所對應之加工進給速率...............38
5-2 本實驗之控制系統之設計.....................................40
5-2.1 輸入及輸出變數.......................................40
5-2.2 控制器之架構.........................................41
5-2.3 模糊化介面...........................................43
5-2.4 進給速率之控制策略...................................45
5-2.5 解模糊化介面.........................................51
5-3 控制程式之流程圖...........................................51
5-4 控制方法之分析與比較.......................................53
5-4.1 切割薄至厚的工件.....................................54
5-4.2 切割厚至薄的工件.....................................60
5-5 控制結果討論...............................................67
第六章 結論與建議................................................. 69
參考文獻...........................................................7
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
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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