1,721,020 research outputs found
Methods for Testing the Random Utility Model
No full textThe Random Utility Model, central in stochastic choice theory, is equivalent to assume that a probability vector belongs to a convex cone. We investigate its underlying geometry, introduce two new testing procedures, and compare them by simulation
Voting behaviour in municipal elections in Italy: a quantitative analysis based on Ecological Inference
No full textMunicipal elections in Italy provide a fruitful context where specific vote transitions may be associated to meaningful categories of voting behaviour. After presenting a modern methodology of ecological inference and outlining its properties, we study how to interpret, in the light of the literature on voting behaviour, the most relevant entries of three connected tables of voting transitions that can be estimated in municipal elections with runoff: (i) party voted at the previous regional election versus party voted at the municipal election, (ii) party voted at the municipal election versus candidate mayor voted in the same election,(iii) candidate mayor voted initially versus candidate mayor voted at the runoffs. An application to the 2011 election in Milan and to the 2012 election in Parma is presented
Critical Flow Method: A New Reliability Allocation Approach for a Thermonuclear System
No full textIn the present work, starting from well-known methodologies, a new reliability allocation method [critical flow method (CFM)] has been proposed. We focused on the most important conventional methods and discussed their limitations in order to motivate the current research. The results show the main common problem of the most conventional reliability allocation methods: they are developed for complex systems with series configurations but not for series–parallel ones. The consequence is an increase of the required units' reliability (series configuration) in order to guarantee the reliability system target. Actually, the design and manufacturing of a subsystem with an extremely low failure rate would consume a considerable amount of economic resources. The proposed method can solve the shortcomings of the conventional methods with a new reliability approach useful to series–parallel configurations in order to obtain an important cost saving. The CFM has been applied to a liquid nitrogen cooling installation in a thermonuclear system, with many series–parallel configurations in order to guarantee the whole safety system. The proposed technique can be applied to working complex systems, and, in general, in the design phase of new installations. By comparing the CFM application results with real parameters, the new technique has been validated. The computational results clearly demonstrate the advantages of the proposed method. In particular, by applying the method to series–parallel configurations, it allocates failure rates higher than conventional methods, with a component cost reduction. Copyright © 2015 John Wiley & Sons, Ltd
Modeling and simulation of an assembly line: A new approach for assignment and optimization of activities of operators
No full textIn the paper we will suggest an approach based on modeling and simulation for the assignment of activities to the operators of a flexible assembly line. Thanks to the above approach, it will be possible to optimize the workload of each operator, in particular to reduce nonvalue and increase saturation. Through the adoption of a specific modeling logic, we can simulate lines with high flexibility of manufacturing and assembly, in various industrial sectors. Starting from the analysis of a real case and following an incremental approach, a simulation model has been realized, verified and validated, which allows to obtain useful information about: production mix; percentages of saturation; lead time and optimization of the assembly line. Copyright © (2011) by CAL-TEK S.r.l
A revised Brown and Payne model of voting behaviour applied to the 2009 elections in Italy
No full textWhen elections are close in time, voters may stick to their preferred party or chose a different option for several reasons; reliable estimates of the amount of transitions across the available options can allow to answer a number of relevant questions about electoral behaviour. We describe a modified version of the model due to Brown and Payne (J Am Stat Assoc 81:453–460, 1986) and argue that it is based on simple, yet realistic, assumptions with a direct interpretation in terms of individual behaviour and compares well with other models proposed more recently. We apply the model to an Italian borough where, during June 2009, two elections were held simultaneously and a runoff took place two weeks later. Estimates of the joint distribution of voters between the European Parliament election and the other two elections provide evidence of substantially different kinds of voting behaviour which, given the specific context, we interpret in the light of the recent literature on the subject
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