Fasso A.,University of Bergamo
Stochastic Environmental Research and Risk Assessment | Year: 2013
This paper presents a general spatio-temporal model for assessing the air quality impact of environmental policies which are introduced as abrupt changes. The estimation method is based on the EM algorithm and the model allows to estimate the impact on air quality over a region and the reduction of human exposure following the considered environmental policy. Moreover, impact testing is proposed as a likelihood ratio test and the number of observations after intervention is computed in order to achieve a certain power for a minimal reduction. An extensive case study is related to the introduction of the congestion charge in Milan city. The consequent estimated reduction of airborne particulate matters and total nitrogen oxides motivates the methods introduced while its derivation illustrates both implementation and inferential issues. © 2013 Springer-Verlag Berlin Heidelberg.
Kalchschmidt M.,University of Bergamo
International Journal of Production Economics | Year: 2012
The paper focuses on best practices in demand forecasting. Literature has addressed the best practice concept under three different perspectives. According to the universalistic perspective, some forecasting practices are universally effective regardless of the context in which companies operate. In the contingent perspective, the effectiveness of forecasting practices depends on the specific kind of context each company faces. A third perspective is the configurational one, which asserts that there are synergistic effects among best practices. In this work, we compare these different perspectives by designing and testing different sets of propositions that underline the aforementioned perspectives. Analysis is conducted by collecting data of more than 500 companies in different countries via the 4th edition of the Global Manufacturing Research Group (GMRG IV) questionnaire. The results demonstrate that each perspective has some empirical support. © 2012 Elsevier B.V. All rights reserved.
Garattini R.,University of Bergamo
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
In the framework of Hor&caronava-Lifshitz theory, we study the eigenvalues associated with the Wheeler-DeWitt equation representing the vacuum expectation values associated with the cosmological constant. The explicit calculation is performed with the help of a variational procedure with trial wave functionals of the Gaussian type. We analyze both the case with the detailed balanced condition and the case without it. In the case without the detailed balance, we find the existence of an eigenvalue depending on the set of coupling constants (g2, g3) and (g4, g 5, g6), respectively, and on the physical scale. © 2012 American Physical Society.
Pinto R.,University of Bergamo
International Journal of Production Economics | Year: 2012
This paper addresses a rationing problem in a two-level, vertically integrated distribution system composed of one manufacturer and several retail points. The motivating case, developed in the vending machine sector and modeled as a newsvendor-like problem, is representative of many real settings where short-term changes in demand can be substantial while capacity modification is not a viable option. The paper provides an analytical discussion of the problem from two different standpoints: a pure profit-maximization perspective and a minimum service-level perspective, both subject to a product availability constraint that affects the service level the company can provide, and the related expected profit. By analyzing the Lagrangean formulation of the problem, we devise efficient computational procedures based on dichotomy search to find the optimal allotments to retailers, maximizing the expected profit and ensuring a minimum service level. Then, we extend the analysis to the evaluation of the highest service level that can be provided, under a product availability constraint. We identify conditions such that the proposed search procedures succeed in finding the optimal solutions, as well as bounds for the search domains. The proposed approach is legitimated under several demand distribution functions subject to a few commonly adopted restrictions that encompass many of the usually adopted continuous distributions. Finally, the paper presents a three-step decision-making framework using the proposed procedures, summarizing the decision paths the manufacturer might follow in order to optimize the allocation decision. © 2011 Elsevier B.V.
Agency: Cordis | Branch: H2020 | Program: RIA | Phase: FoF-05-2014 | Award Amount: 4.06M | Year: 2015
To meet requirements of mass customisation, the manufacturers of machines and equipment for production of mass customised products need powerful engineering environments to allow for multi-directional exchange of knowledge between product design, service design and manufacturing, as well as customers and other relevant organisations across the value chain, distributed all over the globe. Specifically they need feedback from their business customers to whom they sell their equipment, as well as from the final-product customers. Cloud Manufacturing (CMfg) provides new possibilities for collaborative design of product-services within such distributed enterprise, easily adaptable to highly dynamically changing conditions under which enterprises are developing and manufacturing their product-services. On the other hand, tremendous experiences in social software solutions offer new opportunities for enterprises to capture and share experienced based knowledge among all actors across the value chain. Such enormous amount of knowledge to be gathered and shared under dynamically changing conditions, with wide spectrum of actors involved, having different expertise and working conditions/cultures, ask for effective context sensitive solutions for knowledge capturing and analysis. The objective of DIVERSITY is to create a new product-service engineering environment based on a combination of CMfg, PDM/PLM and social software, as well as a set of software tools to support real time sharing of knowledge among various actors, from the designer up to the customer, aimed at small and medium sized companies producing machines/equipment for mass product manufacturers. A new methodology for concurrent collaborative product-service design applying lean based product design paradigm will be developed. Three manufacturing companies, delivering machines/equipment in three different mass production sectors, will drive the project development.