1,720,977 research outputs found
A Comparison of Benson’s Outer Approximation Algorithm with an Extended Version of Multiobjective Simplex Algorithm
Get PDFThe multiple objective simplex algorithm and its variants work in the decision variable space to find the set of all efficient extreme points of multiple objective linear programming (MOLP). Other approaches to the problem find either the entire set of all efficient solutions or a subset of them and also return the corresponding objective values (nondominated points). This paper presents an extension of the multiobjective simplex algorithm (MSA) to generate the set of all nondominated points and no redundant ones. This extended version is compared to Benson’s outer approximation (BOA) algorithm that also computes the set of all nondominated points of the problem. Numerical results on nontrivial MOLP problems show that the total number of nondominated points returned by the extended MSA is the same as that returned by BOA for most of the problems considered
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
Μέθοδοι βελτιστοποίησης για πολύπλοκα προβλήματα δρομολόγησης και χρονοπρογραμματισμού στόλου οχημάτων
No full textThis PhD dissertation is interested in the development of optimization methods for solving complex and large scale Vehicle Routing and Scheduling Problems (VRSP). The main focus is given on studying the computational efficiency and effectiveness of hybrid metaheuristic algorithms. In an attempt to fill in the gaps of the literature identified earlier, the major effort will focus on the Vehicle Routing Problem with Time Windows (VRPTW) and the proposed optimization methods will be tested on several medium and large scale benchmark data sets. Attention will be also given on other variants of the VRPTW with practical and operational side-constraints namely the Open VRPTW (OVRPTW) and the Heterogeneous Fleet VRPTW (HFVRPTW) and the VRPTW with Multiple Compartments and Commodities (MCCVRPTW). Finally, driven from an industrial application we will examine the integration of the suggested methods within a novel Decision Support System that enables schedulers to tackle VRPTW problems with real life operational constraints. A hybrid Multi Start Local Search and a novel Arc Guided Evolutionary Algorithm are proposed for solving the VRPTW. For both approaches an extensive empirical study is performed and the role of key algorithmic elements is analyzed. Computational experiments demonstrate that the proposed optimization methods obtain the best overall results compared to the current state of the art. Considering the Open VRPTW a formal description is first provided followed by a greedy look-ahead construction heuristic and a hybrid Evolutionary Algorithm. All critical aspects of the problem are captured while experimental results demonstrate the competitiveness of the methods with respect to other approaches. Subsequently, the HFVRPTW is addressed. A novel two phase solution framework is developed called Reactive Variable Neighborhood Tabu Search. Computational experiments show that high quality solutions can be reached via the proposed method illustrating its efficiency and effectiveness. Next a real-life VRPTW is presented that incorporates a number of side constraints such as multiple compartments and commodities, time windows, loading restrictions and limited vehicle fleet size and composition availability. An Adaptive Memory Programming method is proposed to address all critical aspects of the problem. Various computational experiments demonstrate the applicability of the method to real life vehicle routing and scheduling applications. Finally, an industrial Decision Support System is presented that handles the efficient and effective management of waste lube oils collection and recycling operations. The main effort is to examine the integration and cooperation of the vehicle routing and scheduling methods within an Enterprise Resource Planning system. The application of the DSS to an industrial environment improved productivity and competitiveness.Η διδακτορική αυτή διατριβή πραγματεύεται την ανάπτυξη μεθόδων βελτιστοποίησης για την επίλυση πολύπλοκων προβλημάτων δρομολόγησης και χρονοπρογραμματισμού στόλου οχημάτων. Η κύρια προσπάθεια εστιάζεται στη μελέτη της υπολογιστικής δύναμης των υβριδικών μεταευρετικών αλγορίθμων. Σε μια προσπάθεια να καλυφθούν τα κενά της βιβλιογραφίας η διδακτορική αυτή διατριβή έρχεται να προτείνει ιδιαίτερα αποδοτικές και αποτελεσματικές μεθόδους για την επίλυση του Προβλήματος Δρομολόγησης Στόλου Οχημάτων με Χρονικά Παράθυρα (ΠΔΣΟΧΠ) καθώς επίσης και άλλων εκδοχών του. Πιο συγκεκριμένα επιχειρείται για πρώτη φορά η μοντελοποίηση του Ανοικτού ΠΔΣΟΧΠ και η ανάπτυξη νέων μεθόδων για το ΠΔΣΟΧΠ με Ετερογενή Στόλο Οχημάτων. Ακόμη εξετάζεται επισταμένως και επιλύεται μια πραγματική βιομηχανική εφαρμογή με πολλαπλούς επιχειρησιακούς περιορισμούς. Τέλος, οι προτεινόμενες μέθοδοι βελτιστοποίησης ενσωματώνονται σε ένα πραγματικό Σύστημα Υποστήριξης Αποφάσεων. Για το ΠΔΣΟΧΠ προτείνεται μια υβριδική μεταευρετική μέθοδος πολλαπλών εκκινήσεων και ένας πρότυπος και μοντέρνος υβριδικός εξελικτικός αλγόριθμος. Η συγκριτική μέτρηση των επιδόσεων των μεθόδων σε πρότυπα προβλήματα της βιβλιογραφίας κατέδειξε την ανταγωνιστικότητα τους. Ιδιαίτερα δε αναφορικά με τη δεύτερη μέθοδο αξίζει να σημειωθεί ότι παρήγαγε τα καλύτερα αποτελέσματα παγκοσμίως τόσο σε μεσαίας όσο και σε μεγάλης κλίμακας προβλήματα. Η αποτελεσματικότητά τους είναι εμφανής παράγοντας, λύσεις υψηλής ποιότητας σε ανταγωνιστικούς υπολογιστικούς χρόνους σε σύγκριση με άλλες μεθόδους της βιβλιογραφίας. Για το Ανοικτό ΠΔΣΟΧΠ δημιουργείται ένα μαθηματικό μοντέλο το οποίο καλύπτει όλες τις πτυχές του προβλήματος, προτείνεται ένας ιδιαίτερα αποτελεσματικός ευρετικός κατασκευαστικός αλγόριθμος καθώς και ένας υβριδικός εξελικτικός αλγόριθμος. Αποτελέσματα σε πρότυπα προβλήματα της βιβλιογραφίας επαληθεύουν την καταλληλότητα και αποδοτικότητα των αλγορίθμων. Για το ΠΔΣΟΧΠ με Ετερογενή Στόλο Οχημάτων προτείνεται ένας υβριδικός μεταευρετικός αλγόριθμος πολλαπλών εκκινήσεων. Βασισμένος στις βασικές αρχές της Απαγορευμένης Έρευνας, ο αλγόριθμος αυτός συνδυάζει μηχανισμούς μεταβλητών γειτονιών και ευφυείς διαδικασίες εκμάθησης. Η συγκριτική μέτρηση των επιδόσεων του σε πρότυπα προβλήματα της βιβλιογραφίας κατέδειξε την ανταγωνιστικότητά του σε σύγκριση με άλλες μεθόδους. Τέλος, στο πλαίσιο της προσπάθειας μοντελοποίησης προβλημάτων με πραγματικούς επιχειρησιακούς περιορισμούς εξετάστηκε ένα πρόβλημα ζήτησης πολλαπλών προϊόντων τα οποία πρέπει να αποθηκεύονται σε διαφορετικά διαμερίσματα των οχημάτων κατά τη διάρκεια της εξυπηρέτησης των πελατών. Για την επίλυση του προβλήματος αυτού προτείνεται ένας αλγόριθμος Προγραμματισμού Προσαρμόσιμης. Αποτελέσματα σε πρότυπα προβλήματα της βιβλιογραφίας επαληθεύουν την απόδοση και την καταλληλότητα της μεθόδου
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
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