Search results for "Operations"
showing 10 items of 1692 documents
Handling the epistemic uncertainty in the selective maintenance problem
2020
Abstract Nowadays, both continuous and discontinuous operating systems require higher and higher reliability levels in order to avoid the occurrence of dangerous or even disastrous consequences. Accordingly, the definition of appropriate maintenance policies and the identification of components to be maintained during the planned system’s downtimes are fundamental to ensure the reliability maximization. Therefore, the present paper proposes a mathematical programming formulation of the selective maintenance problem with the aim to maximize the system’s reliability under an uncertain environment. Specifically, the aleatory model related to the components’ failure process is well known, where…
Two-Player Noncooperative Games over a Freight Transportation Network''
2004
A game between two players acting on the same road transportation network is considered in this paper. The first player aims at minimizing the transportation costs, whereas the second player aims at maximizing her profit (or, in general, her utility) that is proportional to the flow passing through the arcs under her control. We introduce bilevel linear programming formulations for this problem. We derive conditions of existence and properties of the equilibrium points and propose an algorithm finding a local optimal solution. Finally, we present an application of the model to a real system involving trucks travelling through Europe from a Middle Eastern country.
Testing Profitability of Technical Trading Rules
2017
Technical traders typically rely on back-testing which is defined as the process of testing a trading strategy using relevant historical data. Back-testing usually involves “data mining” which denotes the practice of finding a profitable trading strategy by extensive search through a vast number of alternative strategies. This chapter explains that the data-mining procedure tends to find a strategy which performance benefited most from luck. As a result, the performance of the best strategy in a back test is upward biased. This fact motivates that any back-test must be combined with a data-mining correction procedure that adjusts downward the estimated performance. Another straightforward m…
Efficiency and Productivity of Italian Touris Destinations: A Quantitative Estimation Based on Data Envelopment Analysis and the Malmquist Method
2007
This paper aims to provide a statistical analysis of the relative economic performance of Italian tourist areas. It uses two modelling approaches to estimate the competitiveness of these regions, viz. data envelopment analysis (DEA) and the Malmquist method. Our results show that the competitiveness position of several Italian regions has not improved over the years under consideration.
Analysis of the Relationship Between Context and Solution Plan in Modelling Tasks Involving Estimations
2021
In this chapter we analyse students’ written solution plan of a sequence of modelling tasks involving estimations. Our research objective is to statistically analyse whether there is a relation between the solution plan and the characteristics of the context of the real estimation task. From previous work, we have identified some task variables that are directly related to the context. In this study we have designed a sequence of modelling tasks and we have analysed the productions of N = 224 Spanish pre-service primary school teachers. The results show that there is a relationship between the variables of the task and the solution plan used by the students in each case. From the results of…
European Common Transport Policy and Short‐Sea Shipping: Empirical Evidence Based on Modal Choice Models
2009
Abstract This article aims to find the determinants of mode choice decisions for Spanish full lorry and full container loads shipments to the rest of Europe in four productive sectors: agroindustry, ceramic tiles, motor vehicle parts and household appliances. To this end exhaustive fieldwork was carried out and a database constructed, including 507 observations collected from transport decision‐makers. A binary logit is used to estimate a modal choice model where the two modes considered are road transport and Short‐Sea Shipping. The estimation of the model stresses the importance of a politico‐economic evaluation of how to modify the modal split, paying particular attention to the role tha…
R&D Offshoring and the Productivity Growth of European Regions
2013
The recent increase in R&D offshoring have raised fears that knowledge and competitiveness in advanced countries may be at risk of `hollowing out\'. At the same time, economic research has stressed that this process is also likely to allow some reverse technology transfer and foster growth at home. This paper addresses this issue by investigating the extent to which R&D offshoring is associated with productivity dynamics of European regions. We find that offshoring regions have higher productivity growth, but this positive effect fades down with the number of investment projects carried out abroad. A large and positive correlation emerge between the extent of R&D offshoring and the home reg…
A new approach to exergoeconomic analysis and design of variable demand energy systems
2006
Exergoeconomics is an attractive research field regarding the optimisation of design and operability where complex energy systems are concerned. The different approaches to thermoeconomics can easily achieve optimal or near-optimal solutions for the design of energy systems in industrial applications, characterised by regular energy demand profiles; for applications in buildings, however, the great number of components operating at unsteady conditions due to the demand variability make these methodologies hard to use. Furthermore, in project phases of complex plants such as Combined Heat and Power (CHP) or Combined Heat Cooling and Power (CHCP), energy demand can be satisfied with different…
A Stackelberg-game approach to support the design of logistic terminals
2014
This paper deals with the design of logistic terminals taking Sicily, in the South of Italy, as a case study. It focuses on consolidation terminals for truckers and addresses the problem of optimising location pattern and public share in investments. This problem is solved through a Stackelberg game between the designer and the collective of road carriers. So a bilevel approach combines a system-optimum problem, at the upper level, with the carrier equilibrium problem, at the lower level. The choice behaviour of the lower-level player is simulated by a random utility model. The output of the game suggests that private companies and society should share the investments and the public contrib…
Joint route planning under varying market conditions
2007
PurposeTo provide empirical evidence on the level of savings that can be attained by joint route planning and how these savings depend on specific market characteristics.Design/methodology/approachJoint route planning is a measure that companies can take to decrease the costs of their distribution activities. Essentially, this can either be achieved through horizontal cooperation or through outsourcing distribution to a logistics service provider. The synergy value is defined as the difference between distribution costs in the original situation where all entities perform their orders individually, and the costs of a system where all orders are collected and route schemes are set up simulta…