Search results for "Operations Research"
showing 10 items of 1297 documents
The Latent Factors Behind the Urban Travel Behaviour
2014
Abstract This research aims to explore the impact of latent variables, mirroring the users’ preferences, on the individual decision making process regarding the mode of transport. The paper describes the first results of an ongoing research activity, which derives from a pilot study carried out in Palermo. The authors have administered to a sample of travellers a questionnaire and they simulated the mode choice behaviour referring to the random utility theory. Then the transport demand over the entire area of Palermo has been studied in order to design the cordon pricing scenario with the application of an additional cost on private car dedicated to a selected area of the historic centre of…
Monitoring and prediction in early warning systems for rapid mass movements
2015
Rapid mass movements (RMM) pose a substantial risk to people and infrastructure. Reliable and cost-efficient measures have to be taken to reduce this risk. One of these measures includes establishing and advancing the state of practice in the application of early warning systems (EWSs). EWSs have been developed during the past decades and are rapidly increasing. In this paper, we focus on the technical part of EWSs, i.e., the prediction and timely recognition of imminent hazards, as well as on monitoring slopes at risk and released mass movements. Recent innovations in assessing spatial precipitation, monitoring and precursors of the triggering and deformation of RMM offer new opportunities…
Towards automatic calibration of 2-D flood propagation models
2010
Abstract. Hydraulic models for flood propagation description are an essential tool in many fields and are used, for example, for flood hazard and risk assessments, evaluation of flood control measures, etc. Nowadays there are many models of different complexity regarding the mathematical foundation and spatial dimensions available, and most of them are comparatively easy to operate due to sophisticated tools for model setup and control. However, the calibration of these models is still underdeveloped in contrast to other models like e.g. hydrological models or models used in ecosystem analysis. This has two primary reasons: first, lack of relevant data against which the models can be calibr…
Sustainable vehicle routing based on firefly algorithm and TOPSIS methodology
2019
Abstract In a sustainable management of logistics, transportation plays a crucial role. Traditionally, the main purpose was to solve the Vehicle Routing Problem minimizing the cost associated with the travelled distances. Nowadays, the economic profit cannot be the only driver for achieving sustainability and environmental issues have to be also considered. In this paper, to satisfy the intricate limits involved in real vehicle routing problem, the study has been structured considering different types of vehicles in terms of maximum capacity, velocity and emissions, asymmetric paths, vehicle-client constraints and delivery time windows. The firefly algorithm has been implemented to solve th…
Double index recursive models
1994
The purpose of this document is to study the model belongs to the family of structural equation models with data varying both accross individuals (sectors) and in time. A complete theoretical analysis is developed in this work for the case of a recursive structure. Maximum likelihood estimation and Zellner's "seemingly unrelated equations" estimators (iterated or not) are presented and their asymptotic properties are carefully derived.The application of the estimation methods to the economy morocco produced statistically significant and economic meaningful results. Through a test of exogeneity, the recursivity of the system is confirmed. Policy recommendations are discussed and analyzed.
Variable convexity and peripheral core in an exchange economy
1988
La notion de coopération (ICHIISHI [1981;1982], SCARF [1967;1971;1973], SHAPLEY [1973], SCHLEICHER [1979]), qui passe par la formation d’une coalition, donne naissance à ce que l’on appelle parfois des super-joueurs, c’est-à-dire des groupes de joueurs qui vont finalement se comporter comme des joueurs uniques; autrement dit, la rationalité de ces super-joueurs est identique, dans le principe, à celle d’un agent ésseulé en situation de conflit. Ceci signifie, en fait, que les joueurs sont en mesure d’abdiquer leur pouvoir intrinsèque de décision au profit d’une institution collective provenant d’une coalition à laquelle ils adhèrent. Ce pourquoi, ces êtres intermédiaires sont des entités th…
Stretching the value-satisfaction-loyalty chain by adding value dimensions and cognitive and affective satisfactions
2016
Purpose– Consensus on how value dimensions are drivers of overall perceived value is a widespread reality in consumer behaviour literature. But scanty research has been done on which of these value dimensions best predict customer loyalty. The purpose of this paper is to propose a causal model that examines how PERVAL dimensions of value affect customers’ loyalty, through both cognitive and affective satisfaction.Design/methodology/approach– The model is tested on a sample of 820 Spanish retail customers and the findings suggest that product quality and value for money (cognitive) impact customer loyalty through emotional and social value (affective), with significant direct and indirect ef…
Analyzing heterogeneity on the value, satisfaction, word-of-mouth relationship in retailing
2017
Purpose The literature recognizes the need to study differences in consumer behavior in highly competitive and dynamic markets. In this paper, the authors look at how the heterogeneous evaluation of retailing influences customer satisfaction and loyalty. The purpose of this paper is to analyze unobserved heterogeneity on customer value dimensions perceptions in retail establishments, and their potential effects on positive forms of behavioral outcomes considering customer satisfaction as a mediating variable. Design/methodology/approach On a sample of 820 retail customers, the authors apply a finite mixture structural equation modeling that analyzes unobserved heterogeneity simultaneously.…
A novel heuristic algorithm for the modeling and risk assessment of the COVID-19 pandemic phenomenon
2020
This article belongs to the special issue: Soft computing techniques in materials science and engineering Summarization: The modeling and risk assessment of a pandemic phenomenon such as COVID-19 is an important and complicated issue in epidemiology, and such an attempt is of great interest for public health decision-making. To this end, in the present study, based on a recent heuristic algorithm proposed by the authors, the time evolution of COVID-19 is investigated for six different countries/states, namely New York, California, USA, Iran, Sweden and UK. The number of COVID-19-related deaths is used to develop the proposed heuristic model as it is believed that the predicted number of dai…
A step towards a field based agility test in team sports. A perspective on return to play criteria
2017
Introduction: Agility performance tests can be limited by the requirement for force plates, timing gates and expensive camera systems (Correia et al., 2012; Green, Blake, & Caulfield, 2011) making application into rehabilitation programs practically challenging. The aims of this study were to assess the reliability of a field based 1v1 agility test encompassing perceptualaction performance that could be replicated in applied settings. A secondary aim was to assess the relationship between the 1v1 agility test with a range of physical performance tests including the commonly used Y step test (Paul, Gabbett, & Nassis, 2016). Methods: Twenty-eight male rugby union players volunteered (Mean ± S…