Search results for "Operation"
showing 10 items of 2969 documents
About Supergraphs. Part III
2019
Summary The previous articles [5] and [6] introduced formalizations of the step-by-step operations we use to construct finite graphs by hand. That implicitly showed that any finite graph can be constructed from the trivial edgeless graph K 1 by applying a finite sequence of these basic operations. In this article that claim is proven explicitly with Mizar[4].
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…
Experimental P-T-ro Measurements of Supercritical Mixtures of Carbon Dioxide, Carbon Monoxide, and Hydrogen and Semiquantitative Estimation of Their …
2007
The P-T-ρ behavior of the CO2-CO-H2 system was studied in the supercritical region under operative conditions close to those adopted to perform hydrogenation and hydroformylation reactions in dense CO 2, thus providing new interesting information on this fluid mixture. Experiments were performed in a fixed volume reactor in the temperature range from 298 K to 343 K changing the density and the composition of the fluid phase. The one-component (Hildebrand) solubility parameter of the mixture was estimated from experimentally measured P vs T profiles, and its dependence on the density and composition of the system was analyzed to study the antisolvent effect of the permanent gases. We have fo…
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.
LEADER en España : desarrollo rural, poder, legitimación, aprendizaje y nuevas estructuras
2000
El discurso en torno al cual gira el artículo es que en España la concepción de LEADER como instrumento de desarrollo rural, aún siendo creciente, no debe ocultar aquélla otra que lo concibe como un instrumento de poder político, social y económico. Entre ambas, los diferentes grupos de actores intentan legitimar parte de sus políticas o actuaciones a través de su participación en LEADER. El discurs al voltant del qual gira l'article és que a Espanya la concepció de LEADER com a instrument de desenvolupament rural no n'ha d'amagar una altra que l'entén com a instrument de poder polític, social i econòmic. Entre totes dues, els diferents grups d'actors tracten de legitimar part de les seues …
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…
Proposal of Isobutyl Alcohol as Entrainer To Separate Mixtures Formed by Ethanol and Water and 1-Propanol and Water
2017
Isobutyl alcohol (IBA) has been proposed as a solvent to carry out the dehydration of ethanol and 1-propanol by means of a nonconventional distillation process. In this way, isobaric vapor–liquid equilibrium (VLE) and vapor–liquid–liquid equilibrium (VLLE) data at atmospheric pressure have been obtained for the ternary systems ethanol (1a) + water (2) + IBA (3) and 1-propanol (1b) + water (2) + IBA (3). Then, these data have been correlated to obtain a set of parameters capable of estimating VLE and VLLE. According to the results achieved, distillation sequences to separate water and ethanol or 1-propanol have been proposed. Finally, a study about the minimum amount of entrainer required to…