1,309 research outputs found

    Analyzing urban sprawl patterns through fractal geometry: the case of Istanbul metropolitan area

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    Over the last decade, there has been a rapid increase in the amount of literature on the measurement of urban sprawl. Density gradients, sprawl indexes which are based on a series of measurable indicators and certain simulation techniques are some quantitative approaches used in previous studies. Recently, fractal analysis has been used in analyzing urban areas and a fractal theory of cities has been proposed. This study attempts to measure urban sprawl using a sprawl index and analyses urban form through fractal analysis for characterizing urban sprawl in Istanbul which has not been measured or characterized yet. In this study, measures of sprawl were calculated at each neighborhood level and then integrated within sprawl index through “density” and “proximity” factors. This identifies the pattern of urban sprawl during six periods from 1975 to 2005, and then the urban form of Istanbul is quantified through fractal analysis in given periods in the context of sprawl dynamics. Our findings suggest that the fractal dimension of urban form is positively correlated with the urban sprawl index score when urban growth pattern is more likely “concentrated”. However, a negative relationship has been observed between fractal dimension and sprawl index score when the urban growth pattern changes from the concentrated to the semi-linear form

    LSTM neural networks: Input to state stability and probabilistic safety verification

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    The goal of this paper is to analyze Long Short Term Memory (LSTM) neural networks from a dynamical system perspective. The classical recursive equations describing the evolution of LSTM can be recast in state space form, resulting in a time-invariant nonlinear dynamical system. A sufficient condition guaranteeing the Input-to-State (ISS) stability property of this class of systems is provided. The ISS property entails the boundedness of the output reachable set of the LSTM. In light of this result, a novel approach for the safety verification of the network, based on the Scenario Approach, is devised. The proposed method is eventually tested on a pH neutralization process

    In situ atomic force microscopy in the study of electrogeneration of polybithiophene on Pt electrode

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    Electrochemical AFM technique has been used for the in situ study of the electrogeneration-deposition process of polybithiophene at varying the polymerisation conditions, such as supporting electrolyte, i.e., LiClO4 or tetrabutylammonium hexafluorophosphate, and polymerisation procedure, i.e., either potentiostatic or potentiodynamic method. In order to better follow the evolution of the morphology of the deposit, particularly during the early stages of the polymer film growth, a suitable home-made electrochemical cell has been used

    In vitro fermentation of ten cultivars of barley silage.

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    The fermentation characteristics of whole-crop barley silages from ten different cultivars were evaluated by the in vitro gas production technique. The organic matter degradability of barley silage (62.9% in average) was comparable to those reported in our previous trials for oat (59.7%) and sorghum silages (65.5%); while the maximum gas production rate (5.38 ml/h in average) was slightly lower respect to oat (6.71 ml/h) and sorghum silage (6.74 ml/h). The mean nutritive value (4.00 MJ/kg DM) calculated on the basis of both chemical composition and in vitro fermentation data was comparable to that (4.16 MJ/kg DM) obtained in our previous research performed on corn silage, from crop sowed in the same area

    Food industry digitalization: from challenges and trends to opportunities and solutions

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    Over the last years, manufacturing companies have to face several challenges, mainly related to the volatility of the demand and to the continuously changing requirements, both from the customers and suppliers. In the meantime, new technological roadmaps and suggested interventions in manufacturing systems have been implemented. These solutions aim to exploit the high innovation and economic potential resulting from the continuing impact of rapidly advancing information and communication technology (ICT) in industry. This paper explores these topics focusing on the food sector. Indeed, companies belonging to this industry are facing global challenges, which can be met with the support of the information technologies (IT). The overall goal of this study is to help food companies toward digitalization, with a particular focus on the design and manufacturing processes. From the methodological point of view, Case Study has been used as research method. Furthermore, a questionnaire characterized by the different elements of the Manufacturing Value Modelling Methodology (MVMM) has been developed and used to gather information from companies. A framework for the digitalization process in the food industry has been developed basing on the results of a preliminary literature review and of different focus groups. On completion of the aforementioned framework, a list of enabling technologies has been discussed. These represent the technological solutions for the specific food issues highlighted by the framework. Finally, a case study has been accomplished in order to test and validate the contents' framework. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved

    Food industry digitalization: from challenges and trends to opportunities and solutions

    Get PDF
    Over the last years, manufacturing companies have to face several challenges, mainly related to the volatility of the demand and to the continuously changing requirements, both from the customers and suppliers. In the meantime, new technological roadmaps and suggested interventions in manufacturing systems have been implemented. These solutions aim to exploit the high innovation and economic potential resulting from the continuing impact of rapidly advancing information and communication technology (ICT) in industry. This paper explores these topics focusing on the food sector. Indeed, companies belonging to this industry are facing global challenges, which can be met with the support of the information technologies (IT). The overall goal of this study is to help food companies toward digitalization, with a particular focus on the design and manufacturing processes. From the methodological point of view, Case Study has been used as research method. Furthermore, a questionnaire characterized by the different elements of the Manufacturing Value Modelling Methodology (MVMM) has been developed and used to gather information from companies. A framework for the digitalization process in the food industry has been developed basing on the results of a preliminary literature review and of different focus groups. On completion of the aforementioned framework, a list of enabling technologies has been discussed. These represent the technological solutions for the specific food issues highlighted by the framework. Finally, a case study has been accomplished in order to test and validate the contents\u2019 framework
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