1,720,975 research outputs found
Maintenance management for geographically distributed assets: a criticality-based approach
No full textThis paper provides a model to help decision-makers to choose the daily maintenance strategy for geographically distributed assets (GDA) where sites are located in a wide geographical area and a single maintenance centre is involved in managing the maintenance. A hierarchical structure has been used to represent the Multi-System Multi-Component network (MSMCN). A quantitative framework with sequential steps has been developed to plan a daily mix of maintenance actions. First, a dynamic criticality analysis identifies the critical items. A second screening adopts reliability thresholds to determine components that could be preventively replaced. Finally, an iterative economic comparison procedure selects the activities to schedule day by day. The proposed approach also considers time and resources constraints. The model was applied to a real case study to verify its feasibility. Results were compared to the results obtained implementing the current strategy in terms of total downtime, total number of sites visited and total maintenance cost. It was demonstrated that it is possible to reduce the total maintenance cost and the total number of sites visited in a year by balancing opportunistic and preventive maintenance activities with an appropriate selection of the model's thresholds
On the Geometrical Complexity Index as a Driver for Selecting the Production Technology
No full textEmerging production technologies, in particular Additive Manufacturing (AM), nowadays are extremely suitable for creating highly complex products, tending towards the concept of ‘complexity for free’, which is often associated with AM. However, there are no adequate guidelines to provide decision support for the correct selection of the most economically appropriate technology. Indeed, from literature it has been highlighted the need to develop a technology selection methodology based no longer on production volume but on product complexity. This paper investigates this need by presenting an approach to determine the geometrical (or shape) complexity index of a part, which, combined with the assembly complexity, represents the driver for helping to decide the best production technology (traditional or additive). The geometrical complexity index has been determined based on complexity judgments, provided by CAD modelling experts, for a sample of CAD models. In this way, it has been possible to define a preliminary complexity index model, strictly linked to the CAD model information. The results showed that the geometrical complexity metrics from the literature, if individually considered, are not comprehensive. However, a combination of them makes it possible to obtain an index that best reflects the subjective judgement of the experts. In addition, by combining the geometrical and assembly complexity with a cost analysis it is possible to obtain convenience zones for better selecting the production technology. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG
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
Additive manufacturing in green supply chains: A parametric model for life cycle assessment and cost
No full textThe use of additive manufacturing (AM) can improve the green performance of supply chains. However, adopting a centralized or a decentralized supply chain remains an open issue. A decision support model, that integrates Life Cycle Cost (LCC) and Life Cycle Assessment (LCA) methodologies, is proposed in this paper. The lifecycle of a printed product is parametrized depending on strategic decisions that impact economic and environmental sustainability at once, i.e., the production strategy, the degree of outsourcing and production decentralization. Capital and variable costs have been modelled by adopting the process-based cost modelling (PBCM) approach. The monetary valuation of life cycle assessment (MLCA) has been used to aggregate different environmental impact categories. The green-ability of compared production scenarios is measured through a dimensionless-aggregated metric that, besides the scenario performance, also consider the weights the decision maker(s) should assign to the sustainability dimensions. A numerical application is carried out by comparing three different scenarios (i.e., centralized, decentralized, and mixed). Regarding the used data, results show that fully decentralizing printed product production by renting production capacity and outsourcing post-processing activities is the greenest solution regardless of the weights given to the economic and environmental dimensions
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
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
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
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