1,720,959 research outputs found
A novel pruning algorithm for mining long and maximum length frequent itemsets
No full textFrequent itemset mining is today one of the most popular data mining techniques. Its application is, however, hindered by the high computational cost in many real-world datasets, especially for smaller values of support thresholds. In many cases, moreover, the large number of frequent itemsets discovered is overwhelming. In some real-world applications, it is sufficient to find a smaller subset of frequent itemsets, such as identifying the frequent itemsets with a maximum length. In this paper, we present a pruning algorithm, called LengthSort, that reduces the search space effectively and improves the efficiency of mining frequent itemsets with a maximum length. LengthSort prunes both the items and the transactions before constructing a Frequent Pattern tree structure. Our experiments on several datasets show that the proposed pruning techniques reduce the time needed to discover the frequent itemsets with a maximum length. The proposed pruning algorithm can also be applied to efficiently discover frequent itemsets that are longer than a user-specified threshold
Ambidexterity 4.0: How Adopting Smart Manufacturing Technologies Improves Both Exploitation and Exploration
Full text linkCompanies’ adoption of Smart Technologies to achieve structural ambidexterity: an analysis with SEM
Full text linkThe transition to “Industry 4.0′′ and the adoption of Smart Technologies (STs) are generally driven by expectations of gains in productivity, better control over operations and supply chain processes and, therefore, improved competitiveness. These factors are important to achieve success, but sustainable competitive advantage depends on a company's ability to exploit its current assets, while simultaneously exploring new ways of producing value. The ambidextrous balancing of these two areas requires concerted effort and the capacity to balance paradoxical tensions. Literature has thoroughly covered the aspect of how to overcome the trade-off between exploitation and exploration. However, research has only recently started focusing on the pivotal role that digital technologies may play in this process. Our paper contributes to this nascent literature stream by investigating how STs can operate as antecedents of structural ambidexterity. This study relies on the 3rd CINet Survey (2016–2017) involving over 370 companies worldwide. Leveraging on STs and structural ambidexterity as mediators, we used Structural Equation Modelling to show that manufacturing firms with good business performance are in a favorable position to achieve better innovation performances. Our results shed new light on the current debate around the Industry 4.0 transition, with implications for both academics and practitioners
Critical Observability of Networks of Finite State Machines
No full textThis paper deals with the analysis of critical observability for networks of Finite State Machines (FSMs). Critical observability is a property of FSMs that corresponds to the possibility of detecting whether the current state of an FSM is, or is not, in a set of critical states modeling unsafe operations. The study of this property is relevant in safety-critical applications, as for example Air Traffic Management (ATM) systems where the timely recovery of human operators errors and technical devices disruption is of primary importance in ensuring safety of the ATM procedures. In general, for checking this property, a critical observer is designed which detects on-line the occurrence of critical situations. When a large-scale network of FSMs is considered, the construction of such an observer is prohibitive because of the large computational effort needed. In this paper we present an approach based on bisimulation equivalence which reduces the original network to a smaller one while preserving the critical observability property. Further, we show that a critical observer designed for the reduced network can be utilized for the original network. The advantages of the proposed approach in terms of computational complexity are discussed in the paper
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
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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