1,720,957 research outputs found
A mixed integer linear programming model for crossdocking platform freight flow optimization
No full textA tabu search algorithm applied to the berth allocation-scheduling problem: the case of a terminal container operating in Naples (Italy)
No full text
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
The crossdocking distribution strategy: a mixed integer linear programming model and its extension for a distribution process through container terminal.
No full textAbstract
Crossdocking is a logistic strategy used to improve the effectiveness of goods distribution by aiming to decrease inventory and transportation costs. A distribution network is an integrated set of suppliers, distribution platforms and customers where strategic, tactical and operating decisions related to a single player could produce effects on some (or many) others. The state of the art on crossdocking logistic strategy highlights a mismatch between the description of a crossdocking platform and its mathematical formulation. Unloading, loading, sorting, consolidating, storing, labelling and handling are the activities performed within a crossdocking platform which are not included in the modelling part.
Generally the authors include just the storing activity. These activities could be relevant for some problems such as scheduling, layout and distribution whereas they could be considered irrelevant for some other problems which do not reach the detail level on the internal functioning of the platform such as the location problems. Among these problems, the PhD dissertation deals with the distribution flow problem which consists in determining how to send products from suppliers to customers through crossdocking platforms. The activities performed at the platforms are associated to costs and capacity constraints for the available resources. For this reason a crossdocking platform cannot be represented by a single transshipment node. In order to take into account these features, the crossdocking platform is modelled with a transshipment nodes network: a receiving node which stands for the activities performed on the incoming products, a storing node, which stands for the inventory activity and a shipping node standing for the activities performed on the outgoing products. The literature review on distribution flow problems for the crossdocking strategy underlines another mismatch: the lack of a specific constraint for the transportation efficiency. A model is proposed to fill these gaps. The main idea is that the crossdocking, with appropriate differences, can be formulated as a Fixed Charge Network Flow Problem, well-known NP-hard problem. Two exact approaches, a Branch and Bound and a Branch and Cut algorithm, have been developed in order to solve the problem. These two procedures are customized on the network features and they are different from the default procedures embedded within the most diffused optimization software: Xpress and Cplex. Some pseudo-random instances have been generated with the aim to test the developed model and procedures. For the large instances, the obtained results have been compared with those obtained by the optimization software. The obtained results demonstrate the effectiveness of the developed procedures as well as of the crossdocking strategy in terms of average level of inventory.
The second part of this PhD thesis deals with an application: the case of the distribution process through container terminal. A new model is proposed, extension of the previous one, which allows to take into account the specific features associated a container terminal. Once again, the model is formulated, with appropriate differences, as a Fixed Charge Network Flow Problem. In this case the model is validated with a real instance extracted by the current functioning of the container terminal of Naples (Italy), which represents the case study. Like the previous model, the obtained results validate the crossdocking strategy for the management of the terminal yard. This strategy, in fact, allows to drastically cut the average inventory time
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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