1,720,969 research outputs found
Conceptualization and Design of a Digital Twin for Industrial Logistic Systems. An application in the shipbuilding industry
No full textAs the competition among manufacturing organizations increases, the Digital Twin (DT) technology promoted within the industry 4.0 paradigm can be a fundamental game changer for the development of more efficient smart production systems while preserving the safety of operations. This research contributes to the state of the art in such fields by addressing the problem of the conceptualization, design and development of DT of a logistic system for the shipbuilding industry, where material handling operations are planned and managed in a virtual shipyard space, exploiting the technology of Autonomous Mobile Robots (AMRs) and Collaborative robots (COBOTS), in order to increase the safety and the efficiency of operations. The methodological approach involves the determination of the trajectories travelled by the transporter in the shipyard area, considering the specific mission tasks, the operational and safety issues, as well as the specific conditions of the shipyard area (obstacles, pathways, etc.). The results obtained in a preliminary six-month experimental campaign in real operating conditions validated the system developed and allowed to gather a relevant dataset of the utilization profile of the vehicles, thus allowing for further implementation of advanced data analytics for improving the performance of the system and including additional functions such as the management of the maintenance operation
Design of a Smart Control System for electrophysical dehumidification devices: preliminary results
No full textThe control of indoor climate is a complex problem which involves environmental, social and technical aspects. The relevance of such topic increases when the building and/or the objects inside constitute an historical- cultural heritage, because ancient structures are more vulnerable to climatic agents than modern buildings. In particular, the presence of rising damp is a critical problem because it can originate the development of moulds, and pests thus becoming a substantial source of decay. In addition, rising damp is traditionally considered a structural problem that can be solved only by means of invasive interventions. Recently, the spread of electrokinetic dehumidification devices has opened new opportunities in the field of non-invasive damp remediation, thus extending the scope of smart building technologies. Electrokinetic dehumidification devices however generally lack the possibility of interacting with the surrounding environment and with other smart building technologies. In such context this research addresses the development of a control system for an electrokinetic dehumidification device, based on smart sensing and advanced data analysis promoted by Industry 4.0 smart building technologies. This paper in particular reports the details of a stochastic control system for the operational parameters an electrokinetic dehumidification device based on the assessment of the rising height through the measurement of the impedance on the wall surfac
The role of thermal contribution in the design of AA2024 friction stir welded butt and lap joints: mechanical properties and energy demand
Full text linkAlthough in recent times the use of solid-state welding processes as friction stir welding (FSW) has become increasingly
widespread, for some joint morphologies, as lap joints, there are still signifcantly less data available on both process parameters optimization and energy consumption. In the present paper, the authors investigated the possibility of enhancing the
joint quality in two diferent confgurations, i.e. lap and butt joints, taking into account specifc thermal contribution (STC)
conferred to the weld. Strength, micro-hardness and microstructure were evaluated on the produced AA2024 aluminum alloys
butt and lap joints. The surface response method (RSM) was used to investigate the efects of the main process parameters
and to identify optimal technological parameters in terms of joint resistance, while the specifc energy consumption (SEC) of
the entire process was acquired with the aim to provide design guidelines taking into account, at the same time, mechanical
performance and environmental impact. It was found that the same optimal range of revolutionary pitch can be identifed for
both the confgurations. Additionally, maximizing welding speed, for a given revolutionary pitch, contributes to signifcantly
reduce the environmental impact of the process with no detrimental effect on the joint performance
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
Unit Interval Time and Magnitude Monitoring Using Beta and Unit Gamma Distributions
Full text linkQuick detection of an assignable cause is necessary for process accuracy with respect to the specifications. The aim of this study is to monitor the time and magnitude processes based on unit-interval data. To this end, maximum exponentially weighted moving average (Max-EWMA) control chart for simultaneous monitoring time and magnitude of an event is proposed. To be precise, beta and unit gamma distributions are considered to develop the Max-EWMA chart. The chart’s performance is accessed using average run length (ARL), the standard deviation of run length (SDRL), and different quantiles of the run length distribution through extensive Monte Carlo simulations. Besides a comprehensive simulation study, the proposed charting methodology is applied to a real data set. The results show that the proposed chart is more efficient in detecting small to medium-sized shifts. The results also indicate that simultaneous shifts are detected more quickly as compared to the pure shift
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
Monitoring of the effect of solar radiation and rain on the building envelope with integrated vertical vegetation
Full text linkThe goal of the present paper is the verification of the improvement of the performance of a building envelope with a green wall also in conditions of high irradiance (≥0.6 kW/m2) and with variable meteorological conditions (sunny, cloudy, and rainy), with a focus on intense rainfall and tempest. The object of the analysis has been the Innovation and Technology for Development Center in the University Campus of the Polytechnics of Madrid, where a modular system of integrated vertical vegetation has been installed on the skin of the South and West prospects. The study is based on the analysis of the effective thermoregulation capacity of the system in different climatic situations and has been allowed by a database covering a 3-year period, which contains data from continuous monitoring of the meteorological variations and thermal flows through a weather station and sensors placed on the external surface of the envelope, and on the external and internal surfaces of the wall. The experimentation shows that the use of a green wall on the West prospect is even more valid in conditions of high irradiance, as it allows reducing the temperature of the wall by 10 °C, compared to the scenario without the green wall. The combined effect of rain and solar radiation produces different results on the exposure of the walls, with a visible effect only on the South side
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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