1,720,973 research outputs found
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
A heuristic approach to detect CAD assembly clusters
Full text linkMechanical assemblies are very complex structures, made of many parts of various shapes and sizes with different usages. Consequently, it is challenging to manage them during all the manufacturing processes, from the design to the assembly and the recycling. Aiming to simplify the assembly structure and reduce the number of parts to deal with simultaneously, in literature many works exist on subassemblies identification starting from the CAD assembly model. However, the methods provided loose sight of many details associated with the parts, as well as the fact that the treated model represents a real mechanical assembly which respects precise engineering rules. At this regard, this work introduces a novel methodology to detect meaningful clusters in CAD assembly models. The logic applied relies on engineering knowledge, both of mechanical assemblies' components and of assembling techniques, and on the leveraging of the semantics of components. In particular, referring to general design rules, we have identified some heuristics to exploit to partition the assembly into different types of clusters, such as the symmetry along an axis and the presence of fasteners or welds. It results that the assembly's parts are meaningfully grouped, considering, at the same time, their shape, functionality, and type of contact
Uric acid in CKD: has the jury come to the verdict?
No full textEpidemiological studies show that hyperuricemia independently predicts the development of chronic kidney disease (CKD) in individuals with normal kidney function both in the general population and in subjects with diabetes. As a matter of fact, an unfavorable role of uric acid may somewhat be harder to identify in the context of multiple risk factors and pathogenetic mechanisms typical of overt CKD such as proteinuria and high blood pressure. Although the discrepancy in clinical results could mean that urate lowering treatment does not provide a constant benefit in all patients with hyperuricemia and CKD, we believe that the inconsistency in the results from available meta-analysis is mainly due to inadequate sample size, short follow-up times and heterogeneity in study design characterizing the randomized controlled trials included in the analyses. Therefore, available data support the view that hyperuricemia has a damaging impact on kidney function, while preliminary evidence suggests that treatment of so-called asymptomatic hyperuricemia may be helpful to slow or delay the progression of chronic kidney
Review on the leveraging of design information in 3D CAD models for subassemblies identification
Full text linkIn industrial manufacturing, both in the design and the production phase, the management of modern mechanical assemblies is becoming demanding due to their increasing complexity. The use of stable subassemblies concept constitutes a better alternative, which allows to independently treat smaller groups of the assembly's parts, also to achieve a parallel production. At this regard, several methods for automatic subassemblies identifi-cation, starting from the assembly CAD model, have been provided. However, most of the methodologies proposed rely on human intervention, especially in the model processing to make available essential data, while other details are ignored. After giving the definition of stable subassembly, this paper focuses on the application of stable subassemblies identification to industrial CAD models and highlights the issues arising. With the aim of ensuring a reliable CAD model analysis, starting point of the identification, the possible real engineering situations, both related to assembling methods and modelling techniques, are presented. Ap-proaches to algorithmically address them are then described, with the help of two examples of mechanical assemblies
Automatic Assembly Precedence Detection in Axisymmetric Products
No full textAssembly sequence planning starting from CAD models turned out to be a relevant task in the industrial manufacturing field. To have a successful assembly sequence, the relations between the assembly's parts and the possible interferences during the assembly operations deserve to be investigated. In particular, the collision analysis is the phase in which the movement of each part along some directions is evaluated to assess if it is obstructed by any of the other parts, and according to which the precedence matrix is computed. A lot of work has been done to address the problem, however, existing algorithms need to be improved yet. Among the open issues, the following three result to be the most challenging: the combinatorial explosion of the problem complexity, the limited choice of the assembly directions, and the engineering meaning of parts that is not taken into account, or it is manually given in input by experts. In this paper, an automatic assembly sequence planning approach is introduced. The focus is on the collision detection and precedence analysis for engineering meaningful subassemblies, namely the axisymmetric. Information automatically extracted relying on geometric processing and engineering knowledge, such as parts features and semantic interpretation of mechanical components, is first exploited to identify the subassemblies and, then, to choose the feasible assembly direction, as well as to treat fasteners and deformable parts in a more realistic way. An industrial CAD model of a gearbox is selected as case study to illustrate the approach, also emphasizing the importance of axisymmetric subassemblies
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
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