1,720,977 research outputs found
TORNALAMA ÖNCESİ İŞ PARÇASI YÜZEY PÜRÜZLÜLÜĞÜNÜN, TORNALAMA SONRASI YÜZEY PÜRÜZLÜLÜĞÜ VE GÜÇ TÜKETİMİNE ETKİSİ
No full textAutomatic modelling of photographed parts in CATIA CAD environment
No full textBu çalışmada, çeşitli parçalardan elde edilen fotoğraf görüntülerini kullanarak, CATIA CAD ortamında parçaların otomatik olarak modellenmesini sağlayan bir sistem geliştirilmiştir. Geliştirilen sistem, fotoğraf makinesi ile çekilen prizmatik veya silindirik parçaların fotoğrafları üzerinden kullanıcı seçimine bağlı olarak geometrik eleman tanımlamalarını (doğru, daire, yay ve serbest eğri) yapabilmektedir ve belirlenen geometrik elemanlara ait bilgileri CATIA CAD programının anlayacağı formatta dosyaya kaydedebilmektedir. CATIA CAD program arayüzünde oluşturulan menüler yardımıyla CAD modelinin elde edilmesi gerçekleştirilmiştir. Elde edilen CAD modeli parametrik özelliklere sahip olup CATIA?nın bütün imkânlarının kullanımına açıktır. Sistemin geliştirilmesinde grafik özellikleri, kullanım kolaylığı, CATIA içerisinde VBA kısmı uyumluluğundan dolayı Visual Basic 6.0 programı tercih edilmiştir.In this study, a system developed that can model parts in CATIA CAD program automatically by using photographic images obtained from the parts. The system can recognize geometric entities (lines, circles, arc and free curve) in the image taken with a camera, according to the selection of the user. Knowledge of the entities can be saved in a format that is suitable to CATIA CAD program. CAD models are generated with menus that created in the CATIA CAD interface. CAD models are obtained using the menus prepared in CATIA. The CAD models obtained have parametric features and all CATIA commands can be used for them. Visual Basic 6.0 programing language was preferred to design the system. Because VBA can be used in the CATIA interface to develop programs
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Improving the Prediction Accuracy of Surface Roughness in the Boring Process using Integrated Machine Learning Methods
No full textPrecision boring is essential for achieving high-quality holes, yet attaining the desired surface roughness remains a challenge due to the confined machining environment and the instability of long, slender boring bars. Although simple analytical models exist, they often fall short in accurately predicting surface roughness in boring operations. In machining applications, conducting extensive experiments is limited by high costs and time constraints; thus, small sampling problems occur in the prediction models. Therefore, it is necessary to establish high-accuracy surface roughness prediction models with optimized input features. In this study, an integrated machine learning-based methodology is proposed to overcome these challenges. The approach includes ranking input features by importance, incorporating physics-based features, expanding the feature space, and generating virtual samples to enrich the training data. The results indicate that the proposed model improves prediction accuracy by 27%. The most significant enhancement was observed when virtual samples were added after expanding the feature set with physics-based parameters. These findings contribute to more precise and cost-effective planning in boring operations.Explore related subjects</section
Experimental comparison of the indexable drilling with different U drills on hole quality
No full textU drills are estimated to account for around 53% of all drilling equipment’s market share. This study compared and contrasted the impacts of the balance angle, the U drill length/ diameter ratio, and the extra coolant hole opened in the chip evacuation channel on the hole quality when drilling AA 7075-T651 material. Hole quality was investigated by deviation from diameter, deviation from circularity, deviation from cylindricality, surface roughness, forces, and torque. Three cutting speeds, three feed rates, and four distinct U drills were chosen as input parameters. The studies revealed that when the U drill’s length/diameter ratio increased, the hole quality deteriorated. The best hole quality was nonetheless achieved by the tool with the additional coolant hole. The higher balance angle resulted in improved hole quality. However, it was discovered after looking at the chips and inserts that the chatter only happened while drilling with a U drill that had an additional coolant hole. While the extra coolant hole opened to the chip evacuation channel, it affected the hole quality positively but caused chatter, which negatively affected the inserts. The reasons for these results are discussed in detail.</p
Değiştirilebilir Uçlu Matkap Uygulamaları Üzerine Bir Derleme
No full textDeğiştirilebilir Uçlu Matkap (U Matkap) delik delmeye yarayan bir kesicidir. Dolu malzemeye ön delik olmaksızın büyük çaplarda delik delebilir. Çeşitli yüzey formlarında (eğimli, dışbükey, içbükey vb.) sıkıntısız bir şekilde kullanılabilir. Kesici uçlar köreldiğinde ise kolaylıkla değiştirilebilir. Genelde biri merkezde diğeri ise çevrede olmak üzere iki kesici uç barındırmaktadır. Bu iki uç bazı matkaplarda aynı geometri ve kaplamaya sahipken bazı matkaplarda farklı geometri ve kaplamalar kullanılabilmektedir. Normal helisel matkaptan farklı olarak asimetrik bir geometriye sahiptir. Bu nedenle merkez ve çevresel uçlarda farklı talaş yükleri ve kesme kuvvetleri meydana gelmektedir. Kesme parametrelerinin uygun bir şekilde verilmesiyle kesme kuvvetlerinin, delik yüzey pürüzlülüğünün, daireselliğin ve takım aşınmasının optimum gerçekleşmesi sağlanabilir. Böylelikle bu matkaplar imalatta verimli bir şekilde kullanılabilir. Bu çalışmada farklı malzemelerin U Matkap kullanılarak delinmesi ile ilgili çalışmalar gözden geçirilerek çeşitli konu başlıkları altında incelenmiştir.</p
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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