Search results for "Operations"

An Application of Analytic Network Process in the Planning Process: The Case of an Urban Transformation in Palermo (Italy)

2014

The primary objective of this study is to test the multicriteria analysis application in favor of a selection process among alternative transformations of an urban area in the city of Palermo. The choice is referred to as a strategyoriented one aiming to create “new urban centralities” able to redraw all urban structures that start to activate renewal processes within the existing city. The application of multicriteria analysis technique, such as the Analytic Network Process (ANP) - BOCR model, is due to the need to represent the complexity of the decision problem characterized by interrelations among several elements described by many indicators from different levels. The case study is als…

An environment based approach for the ant colony convergence

2020

Abstract Ant colony optimization (ACO) algorithms are a bio inspired solutions which have been very successful in combinatorial problem solving, also known as NP-hard problems, including transportation system optimization. As opposed to exact methods, which could give the best results of a tested problem, this meta-heuristics is based on the stochastic logic but not on theoretical mathematics demonstration (or only on certain well defined applications). According to this, the weak point of this meta-heuristics is his convergence, its termination condition. We can finds many different termination criteria in the scientific literature, yet most of them are costly in resources and unsuitable f…

Relationship between anthropometric parameters, physiological responses, routes and competition results in formula windsurfing

2012

Formula windsurfing is faster than the Olympic version, due to anumber of unique differences. This study was designed to identify the importance of anthropometric and cardiac factors on the final result of the European Formula Windsurf Championships (2007). We selected 45 competitors (30 amateurs and 15 professionals) of 30±9.77 years of age, a height of 182.6±0.06 cm, a weight of 81.67±7.35 kg and a BMIof 24.7±2.1 kg. They were divided into three groups (PG: 15; TG: 45and GPSG: 12). We followed the recommendations of Carter and Marfell-Jones for the anthropometric measurements. The route, speed, distance and heart rate were recorded using an FRWD W600 GPS (Global Positioning System) unit. …

Addressing Dendritic Cells for Anticancer Immunity

2014

Scenario optimization asset and liability modelling for individual investors

2006

We develop a scenario optimization model for asset and liability management of individual investors. The individual has a given level of initial wealth and a target goal to be reached within some time horizon. The individual must determine an asset allocation strategy so that the portfolio growth rate will be sufficient to reach the target. A scenario optimization model is formulated which maximizes the upside potential of the portfolio, with limits on the downside risk. Both upside and downside are measured vis- `a-vis the goal. The stochastic behavior of asset returns is captured through bootstrap simulation, and the simulation is embedded in the model to determine the optimal portfolio. …

Branch-Price-and-Cut for the Soft-Clustered Capacitated Arc-Routing Problem

2021

The soft-clustered capacitated arc-routing problem (SoftCluCARP) is a variant of the classical capacitated arc-routing problem. The only additional constraint is that the set of required edges, that is, the streets to be serviced, is partitioned into clusters, and feasible routes must respect the soft-cluster constraint, that is, all required edges of the same cluster must be served by the same vehicle. In this article, we design an effective branch-price-and-cut algorithm for the exact solution of the SoftCluCARP. Its new components are a metaheuristic and branch-and-cut-based solvers for the solution of the column-generation subproblem, which is a profitable rural clustered postman tour …

A comparison of two different formulations for Arc Routing Problems on Mixed graphs

2006

[EN] Arc routing problems on mixed graphs have been modelled in the literature either using just one variable per edge or associating to each edge two variables, each one representing its traversal in the corresponding direction. In this paper, and using the mixed general routing problem as an example, we compare theoretical and computationally both formulations as well as the lower bounds obtained from them using Linear Programming based methods. Extensive computational experiments, including some big and newly generated random instances, are presented.

Arc routing problems: A review of the past, present, and future

2020

[EN] Arc routing problems (ARPs) are defined and introduced. Following a brief history of developments in this area of research, different types of ARPs are described that are currently relevant for study. In addition, particular features of ARPs that are important from a theoretical or practical point of view are discussed. A section on applications describes some of the changes that have occurred from early applications of ARP models to the present day and points the way to emerging topics for study. A final section provides information on libraries and instance repositories for ARPs. The review concludes with some perspectives on future research developments and opportunities for emergin…

New Heuristic Algorithms for the Windy Rural Postman Problem

2005

[EN] In this paper we deal with the windy rural postman problem. This problem generalizes several important arc routing problems and has interesting real-life applications. Here, we present several heuristics whose study has lead to the design of a scatter search algorithm for the windy rural postman problem. Extensive computational experiments over different sets of instances, with sizes up to 988 nodes and 3952 edges, are also presented. (c) 2004 Elsevier Ltd. All rights reserved.

A branch-and-cut algorithm for the Profitable Windy Rural Postman Problem

2016

[EN] In this paper we study the profitable windy rural postman problem. This is an arc routing problem with profits defined on a windy graph in which there is a profit associated with some of the edges of the graph, consisting of finding a route maximizing the difference between the total profit collected and the total cost. This problem generalizes the rural postman problem and other well-known arc routing problems and has real-life applications, mainly in snow removal operations. We propose here a formulation for the problem and study its associated polyhedron. Several families of facet-inducing inequalities are described and used in the design of a branch-and-cut procedure. The algorithm…