353 research outputs found

    A Note On The Use Of Quantile Regression In Beta Convergence Analysis

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    We discuss how to interpret conflicting results obtained by the use of quantile regression methods in growth regression tests of I̊2-convergence hypothesis and the results obtained by nonparametric methods. We show that the assumption of linearity may cause the non-rejection of the I̊2-convergence hypothesis by quantile regression. We also show that using a nonparametric form of quantile regression, we can reject the hypothesis of I̊2-convergence and confirm the results of divergence and formation of convergence clubs. We illustrate the discussion by using the conflicting results on convergence found in the dataset of per-capita income of Brazilian municipalities between 1970 and 1996.352Andrade, E., Laurini, M.P., Madalozzo, R., Valls Pereira, P.V., Convergence clubs among Brazilian municipalities (2004) Economics Letters, 83 (2), pp. 179-184Andrade, E., Laurini, M.P., Madalozzo, R., Valls Pereira, P.V., Testing convergence across municipalities in Brazil using quantile regression (2003) In Proceedings of 18 Meeting of European Economic AssociationAzariadis, C., Drazen, A., Threshold externalities in economic development (1990) Quarterly Journal of Economics, 105 (2), pp. 501-526Barreto, R.A., Hughes, A.W., Under performers and over achievers: A quantile regression analysis of growth (2004) Economic Record, 80, pp. 17-35Barro, R., Economic growth in a cross-section of countries (1991) Quarterly Journal of Economics, 106 (2), pp. 407-443Bernard, A., Durlauf, S., Interpreting tests of the convergence hypothesis (1996) Journal of Econometrics, 71, pp. 161-173Bosch, R.J.Y., Ye, Y., Woodworth, G.G., A Convergent algorithm for the quantile regression with smoothing splines (1995) Computational Statistics & Data Analysis, 19, pp. 613-630Durlauf, S., Johnson, P., Temple, J., Handbook of Economic Growth, chap (2005) Growth econometrics, pp. 5-41. , North-HollandFan, J., Yao, Q., (2003) Nonlinear Time Series: Nonparametric and Parametric Methods, , SpringerFan, J., Zhang, C., Zhang, J., Generalized likelihood ratio statistics and Wilks phenomenon (2001) The Annals of Statistics, 29, pp. 153-193Friedman, M., Do old fallacies ever die? (1992) Journal of Economic Literature, 30, pp. 2129-2132Hardle, W., (1990) Applied Nonparametric Regression, , Cambridge University PressKoenker, R., Basset, G., Regression quantiles (1978) Econometrica, 46, pp. 33-50Koenker, R., Galton, Edgeworth, Frisch, and prospects for quantile regression in econometrics (2000) Journal of Econometrics, 95, pp. 347-374Koenker, R., (2005) Quantile Regression, , Cambridge University PressLaurini, M.P., Andrade, E., Valls Pereira, P.V., Income convergence clubs for Brazilian Municipalities: A non-parametric analysis (2005) Applied Economics, 37 (18), pp. 2099-2118Lucas, R., On the mechanics of economic development (1988) Journal of Monetary Economics, 22 (1), pp. 3-42Mello, M., Novo, A., (2002) The new empirics of economic growth: Quantile regression estimation of growth equations, , Unpublished Working PaperMello, M., Perrelli, R., Growth equations: A quantile regression exploration (2003) The Quarterly Review of Economics and Finance, 43 (4), pp. 643-667Miles, W., Human capital and economic growth: A quantile regression approach (2004) Applied Econometrics and International Development, 2Nelsen, R., (1999) An Introduction to Copulas, , Lectures Notes in Statistics, Springer VerlagQuah, D., Galton's fallacy and tests of convergence hypothesis (1993) Scandinavian Journal of Economics, 95 (4), pp. 427-443Quah, D., Empirics for growth and distribution: Stratificiation, polarization and convergence clubs (1997) Journal of Economic Growth, 2, pp. 27-59Romer, P., Increasing returns and long run growth (1986) Journal of Political Economy, 94 (5), pp. 1002-1037Solow, R., A contribution to the theory of economic growth (1956) Quarterly Journal of Economics, 70, pp. 65-94Swan, T., Economic growth and capital accumulation (1956) Economic Record, 32, pp. 334-36

    Pre-harvest sugarcane burning:A statistical analysis of the environmental impacts of a regulatory change in the energy sector

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    We evaluate the efficiency of a regulatory change in sugarcane production (Law N°11.241/2002) that gradually banish the pre-harvest burning in the sugarcane production sector in the São Paulo state in Brazil, analyzing the occurrences of fires detected by satellite. To estimate the spatio-temporal dynamics of fire occurrence we use a structural representation in a log-Gaussian Cox process, decomposing the intensity function in components of trend, seasonality, cycles, covariates and spatial effects. The results have provided evidence that the trend component reflects the consistent reduction in fire occurrences, suggesting the efficiency of the mitigation actions implemented in the São Paulo state, and indicating a permanent advance in the environmental sustainability of this form of renewable energy production

    Shortest path with acceleration constraints: complexity and approximation algorithms

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    We introduce a variant of the Shortest Path Problem (SPP), in which we impose additional constraints on the acceleration over the arcs, and call it Bounded Acceleration SPP (BASP). This variant is inspired by an industrial application: a vehicle needs to travel from its current position to a target one in minimum-time, following pre-defined geometric paths connecting positions within a facility, while satisfying some speed and acceleration constraints depending on the vehicle position along the currently traveled path. We characterize the complexity of BASP, proving its NP-hardness. We also show that, under additional hypotheses on problem data, the problem admits a pseudo-polynomial time-complexity algorithm. Moreover, we present an approximation algorithm with polynomial time-complexity with respect to the data of the original problem and the inverse of the approximation factor Ï”. Finally, we present some computational experiments to evaluate the performance of the proposed approximation algorithm

    THE MAXIMIZATION OF THE 4TH DIMENSION OF THE BUILDING SITE

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    Abstract. The aim of the contribution is to elaborate the digitalization of the construction process and of the management of the construction for both the organization of work activity and safety on the building site. The BIM methodology requires a digital implementation of construction through the creation of virtual models pertaining to the various professions involved. The CoSIM, acronym for Construction Site Information Modelling, is the application of BIM in the building site and where the federated model of the design phase materializes. The goal of the methodology developed is to obtain an elevated quality standard of the project, while trying to maximise costs and time as much as possible to favour an increase in the level of safety and security on the building site. The BSS, Building Site Safety, will allow a maximization of the safety design, not only by graphically depicting work activity but also forming a digital system for the documentation of the building site. To support this, the model is integrated with a simple plug-in which contains a library of objects to use for the designing and planning of safety on site, from general information to state of emergency warning. Thanks to the combination of the CoSIM and the BSS we can have a reduction of the variant, a reduction of time and costs due to an improved planning of work activity and allows the worker to be aware of all the modalities of procedure before entering the building site

    Cationic carbosilane dendrimers and oligonucleotide binding: an energetic affair

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    GENERATION 2 CATIONIC CARBOSILANE DENDRIMERS HOLD GREAT PROMISE AS INTERNALIZING AGENTS FOR GENE THERAPY AS THEY PRESENT LOW TOXICITY AND RETAIN AND INTERNALIZE GENETIC MATERIAL AS OLIGONUCLEOTIDE OR SIRNA. IN THIS WORK WE CARRIED OUT A COMPLETE IN SILICO STRUCTURAL AND ENERGETICAL CHARACTERIZATION OF THE INTERACTIONS OF A SET OF 2G CARBOSILANE DENDRIMERS, SHOWING DIFFERENT AFFINITY TOWARDS TWO SINGLE STRAND OLIGONUCLEOTIDE (ODN) SEQUENCES IN VITRO. OUR SIMULATIONS PREDICT THAT THESE FOUR DENDRIMERS AND THE RELEVANT ODN COMPLEXES ARE CHARACTERIZED BY SIMILAR SIZE AND SHAPE, AND THAT THE MOLECULE-SPECIFIC ODN BINDING ABILITY CAN BE RATIONALIZED ONLY CONSIDERING A CRITICAL MOLECULAR DESIGN PARAMETER: THE NORMALIZED EFFECTIVE BINDING ENERGY \u394GBIND,EFF/NEFF I.E., THE PERFORMANCE OF EACH ACTIVE INDIVIDUAL DENDRIMER BRANCH DIRECTLY INVOLVED IN A BINDING INTERACTIO

    Robust Statistical Processing of Long-Time Data Series to Estimate Soil Water Content

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    The research presented in this paper aims at providing a statistical model that is capable of estimating soil water content based on weather data. The model was tested using a long-time series of field experimental data from continuous monitoring at a test site in OltrepĂČ Pavese (northern Italy). An innovative statistical function was developed in order to predict the evolution of soil–water content from precipitation and air temperature. The data were analysed in a framework of robust statistics by using a combination of robust parametric and non-parametric models. Specifically, a statistical model, which includes the typical seasonal trend of field data, has been set up. The proposed model showed that relevant features present in the field of experimental data can be obtained and correctly described for predictive purposes

    A Molecular Dynamics approach to investigate the tribological behaviour of Al-Si and α-Al2O3-Si interfaces at the nanoscale

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    The evolution of Information and Communications Technology (ICT) and Micro-Nano Electromechanical System (MEMS/NEMS) makes evident the trend towards the progressive miniaturisation of devices. The energy efficiencies at the nanoscale are, in turn, significantly lowered by friction force. The friction force depends not only on the tribological pair parameters and normal loads, but also on the crystalline structure of the materials in contact, their surface chemistry and roughness. Our research focuses on the nanometric friction force using Molecular Dynamics (MD) simulations. An investigation of a system comprising a hemispheric silicon tip sliding on an aluminium oxide flat surface, aiming at understanding the interactions between the materials from an atomistic standpoint, was thus conducted

    PREFACE

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    Abstract. Simply defined, a Smart City is a city overlaid by a digital layer, which is used for the governance of the city. A Smart City uses intelligent technology to enhance our quality of life in urban environments, bringing together people and data from disparate sources such as sensors, demographics, topographic and 3D mapping, Building Information Models and many more. Increasingly, Smart Cities use this data in a variety of ways, to address key challenges related to transportation, communications, air quality, noise, well-being of the citizens, decision making relating to education and health and urban planning, as well as in relation to initiatives such as startups and fostering economic growth and employment within the city. As more data becomes available, the challenges of storing, managing and integrating such data are also multiplied.The first Urban Data Management Symposium (UDMS) was held in 1971 in Bonn, Germany, made the choice of hosting the 6th international conference on Smart Data and Smart Cities (SDSC) in Stuttgart a very natural one. SDSC was established in 2016 as the successor of the UDMS, and this year we celebrate the 40th anniversary of the series of symposia and conferences. The SDSC 2021 will be part of the scientific week on intelligent cities at HFT Stuttgart. Together four events were held during the week of 14th – 17th September 2021, and alongside SDSC participants were invited to attend the "Energy, water and food for the cities of the future" conference, the "LIS-City – liveable, intelligent, and sustainable City" workshop, and the mobility day Stuttgart. Participant interaction – and the ability to attend sessions across the four events – was particularly encouraged. SDSC 2021 itself was organised by the Urban Data Management Society (UDMS www.udms.net), ISPRS and HFT Stuttgart (the University of Applied Science Stuttgart), and Professor Volker Coors Chaired the SDSC committee.As in previous years, three key conference themes were proposed to represent the Smart Cities: Smart Data (sensor network databases, on-the-fly data mining, geographic and urban knowledge modeling and engineering, green computing, urban data analytics and big data, big databases and data management), Smart People (volunteered information, systems for public participation) and Smart Cities (systems of territorial intelligence, systems for city intelligence management, 3D modeling of cities, internet of things, social networks, monitoring systems, mobility and transportation, smart-city-wide telecommunications infrastructure, urban knowledge engineering, urban dashboard design and implementation, new style of urban decision-making systems, geovisualization devoted to urban problems, disaster management systems).This volume consists of 14 papers, which were selected from 41 submissions on the basis of double blind review, with each paper being reviewed by a minimum of three reviewers. These papers present novel research concerning the use of spatial information and communication technologies in Smart Cities, addressing different aspects of Smart Data and Smart Citizens. The selected papers tackle different aspects of Smart Cities: 3D; Citizen Engagement; transport, sustainable mobility; dashboards and web GIS; citizen engagement and participation; sensors; urban decision making.The editors are grateful to the members of the Scientific Committee for their time and valuable comments, which contributed to the high quality of the papers. Reviews were contributed by: Alias Abdul-Rahman, Giorgio Agugiaro, Ken Arroyo Ohori, John Barton, Martina Baucic, Filip Biljecki, Lars Bodum, Pawel Boguslawski, Azedine Boulmakoul, Matteo Caglioni, Caesar Cardenas, Eliseo Clementini, Volker Coors, Youness Dehbi, Abdoulaye Abou DiakitĂ©, Adil El Bouziri, Claire Ellul, Tarun Ghawana, Gesquiere Gilles, Didier Grimaldi, Ori Gudes, Stephen Hirtle, Martin Kada, Lamia Karim, Robert Laurini, Christina Mickrenska-Cherneva, Christopher Petit, Alenka Poplin, Ivana Racetin, Dimos Pantazis, Preston Rodrigues, Camilo Leon Sanchez, Genoveva Vargas Solar, Nils Walravens, Parag Wate, Besri Zineb, Sisi Zlatanova. We are also grateful to the work of the local organising committee at HFT Stuttgart, without whom this conference would not have been possible

    PREFACE

    Get PDF
    Abstract. Simply defined, a Smart City is a city overlaid by a digital layer, which is used for the governance of the city. A Smart City uses intelligent technology to enhance our quality of life in urban environments, bringing together people and data from disparate sources such as sensors, demographics, topographic and 3D mapping, Building Information Models and many more. Increasingly, Smart Cities use this data in a variety of ways, to address key challenges related to transportation, communications, air quality, noise, well-being of the citizens, decision making relating to education and health and urban planning, as well as in relation to initiatives such as startups and fostering economic growth and employment within the city. As more data becomes available, the challenges of storing, managing and integrating such data are also multiplied.The first Urban Data Management Symposium (UDMS) was held in 1971 in Bonn, Germany, made the choice of hosting the 6th international conference on Smart Data and Smart Cities (SDSC) in Stuttgart a very natural one. SDSC was established in 2016 as the successor of the UDMS, and this year we celebrate the 40th anniversary of the series of symposia and conferences. The SDSC 2021 will be part of the scientific week on intelligent cities at HFT Stuttgart. Together four events were held during the week of 14th – 17th September 2021, and alongside SDSC participants were invited to attend the "Energy, water and food for the cities of the future" conference, the "LIS-City – liveable, intelligent, and sustainable City" workshop, and the mobility day Stuttgart. Participant interaction – and the ability to attend sessions across the four events – was particularly encouraged. SDSC 2021 itself was organised by the Urban Data Management Society (UDMS www.udms.net), ISPRS and HFT Stuttgart (the University of Applied Science Stuttgart), and Professor Volker Coors Chaired the SDSC committee.As in previous years, three key conference themes were proposed to represent the Smart Cities: Smart Data (sensor network databases, on-the-fly data mining, geographic and urban knowledge modeling and engineering, green computing, urban data analytics and big data, big databases and data management), Smart People (volunteered information, systems for public participation) and Smart Cities (systems of territorial intelligence, systems for city intelligence management, 3D modeling of cities, internet of things, social networks, monitoring systems, mobility and transportation, smart-city-wide telecommunications infrastructure, urban knowledge engineering, urban dashboard design and implementation, new style of urban decision-making systems, geovisualization devoted to urban problems, disaster management systems).This volume consists of 18 papers, which were selected from 41 submissions on the basis of peer review. These papers present novel research concerning the use of spatial information and communication technologies in Smart Cities, addressing different aspects relating to Smart Data. Selected papers tackle different aspects of Smart Cities: transport, sustainable mobility; dashboards and web GIS; citizen engagement and participation; sensors; urban decision making.The editors are grateful to the members of the Scientific Committee for their time and valuable comments, which contributed to the high quality of the papers. Reviews were contributed by: Alias Abdul-Rahman, Giorgio Agugiaro, Ken Arroyo Ohori, John Barton, Martina Baucic, Filip Biljecki, Lars Bodum, Pawel Boguslawski, Azedine Boulmakoul, Matteo Caglioni, Caesar Cardenas, Eliseo Clementini, Volker Coors, Youness Dehbi, Abdoulaye Abou DiakitĂ©, Adil El Bouziri, Claire Ellul, Tarun Ghawana, Gesquiere Gilles, Didier Grimaldi, Ori Gudes, Stephen Hirtle, Martin Kada, Lamia Karim, Robert Laurini, Christina Mickrenska-Cherneva, Christopher Petit, Alenka Poplin, Ivana Racetin, Dimos Pantazis, Preston Rodrigues, Camilo Leon Sanchez, Genoveva Vargas Solar, Nils Walravens, Parag Wate, Besri Zineb, Sisi Zlatanova. We are also grateful to the work of the local organising committee at HFT Stuttgart, without whom this conference would not have been possible
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