A solution approach for dynamic vehicle and crew scheduling

In this paper, we discuss the dynamic vehicle and crew schedulingproblem and we propose a solution approach consisting of solving asequence of optimization problems. Furthermore, we explain why itis useful to consider such a dynamic approach and compare it witha static one. Moreover, we perform a sensitivity analysis on ourmain assumption that the travel times of the trips are knownexactly a certain amount of time before actual operation.We provide extensive computational results on some real-world datainstances of a large public transport company in the Netherlands.Due to the complexity of the vehicle and crew scheduling problem,we solve only small and medium-sized instances with such a dynamicapproach. We show that the results are good in the case of asingle depot. However, in the multiple-depot case, the dynamicapproach does not perform so well. We investigate why this is thecase and conclude that the fact that the instance has to be splitin several smaller ones, has a negative effect on the performance.transportation;vehicle and crew scheduling;large-scale optimization;dynamic planning

A solution approach for dynamic vehicle and crew scheduling

In this paper, we discuss the dynamic vehicle and crew scheduling problem and we propose a solution approach consisting of solving a sequence of optimization problems. Furthermore, we explain why it is useful to consider such a dynamic approach and compare it with a static one. Moreover, we perform a sensitivity analysis on our main assumption that the travel times of the trips are known exactly a certain amount of time before actual operation. We provide extensive computational results on some real-world data instances of a large public transport company in the Netherlands. Due to the complexity of the vehicle and crew scheduling problem, we solve only small and medium-sized instances with such a dynamic approach. We show that the results are good in the case of a single depot. However, in the multiple-depot case, the dynamic approach does not perform so well. We investigate why this is the case and conclude that the fact that the instance has to be split in several smaller ones, has a negative effect on the performance

Issues on simulation of the railway rolling stock operation process – a system and literature review

Railway traffic simulation, taking into account operation and maintenance conditions, is not a new issue in the literature. External effects in such networks (eg. level crossings) were not taken into account in studies. The used models do not take into account sufficiently the process of degradation and recovery of the network. From the technical side, currently carried out simulations are made using similar approaches and techniques as in the initial stage of research. Well-established work in this area could be the basis for evaluation of new solutions. However, the progress in simulation tools during the last years, especially in performance and programming architecture, attempt to create a modern simulation tool. In the paper were presented the main assumptions for the evaluated event-based simulation method, with application to stiff-track transportation network

Delay and disruption management in local public transportation via real-time vehicle and crew re-scheduling: a case study

Local public transport companies, especially in large cities, are facing every day the problem of managing delays and small disruptions. Disruption management is a well-established practice in airlines and railways. However, in local public transport the approaches to these problems have followed a different path, mainly focusing on holding and short-turning strategies not directly associated with the driver scheduling. In this paper we consider the case of the management of urban surface lines of Azienda Trasporti Milanese (ATM) of Milan. The main issues are the service regularity as a measure of the quality of service, and the minimization of the operational costs due to changes in the planned driver scheduling. We propose a simulation-based optimization system to cope with delays and small disruptions that can be effectively used in a real-time environment and takes into account both vehicle and driver scheduling. The proposed approach is tested on real data to prove its actual applicability

Diseño de un sistema logístico de acopio y distribución de un producto alimenticio perecedero no refrigerado para el área de influencia del Valle del Cauca

En Colombia, las necesidades alimentarias de las poblaciones más vulnerables no están del todo satisfechas debido a factores que incluyen, entre otros, a la baja capacidad adquisitiva de dichas poblaciones, a la escasez de alimentos nutritivos y complementarios y a la falta de capacidad de distribución de dichos alimentos a los rincones más apartados de la geografía nacional, tal como se expone en los diarios nacionales como El Tiempo2, el Colombiano3 y el Heraldo4. Surgió entonces, en el año 1976 en el Instituto Colombiano de Bienestar Familiar (ICBF), un producto alimenticio rico en nutrientes, relativamente fácil de producir y preparar en casa, que podía ser repartido entre los sectores más vulnerables de la sociedad colombiana y que, al ser suministrado a niños, ancianos, discapacitados y demás poblaciones sensibles, logró llenar el vacío de la deficiencia alimentaria existente. La Bienestarina®, producto gratuito, financiado por el gobierno nacional, logra este cometido. Fabricada por la empresa Ingredion de Colombia S.A., en dos plantas ubicadas en los municipios de Cartago, departamento del Valle del Cauca y Sabanagrande, departamento del Atlántico. Distribuida y almacenada en todo el territorio nacional y suministrada a la población objetivo por unidades ejecutoras (escuelas, centros comunales, iglesias, hogares comunitarios, centros geriátricos, entre otros). En el departamento del Valle del Cauca se ha identificado que, según el modelo de distribución del producto, la empresa fabricante Ingredion de Colombia S.A. se responsabiliza de la entrega del producto sólo hasta los puntos primarios de entrega y no hasta los consumidores (beneficiarios) del producto. En este proyecto de investigación se formula una solución alternativa de logística y distribución que cumple con las necesidades de entrega del producto de acuerdo con la demanda, propone un modelo de ruteo según las condiciones viales del Valle del Cauca, para lo cual se identificaron las principales vías, y las características, que comunican a todos los municipios del departamento. El modelo se basa en los históricos de demanda del producto y por medio de dos software de ruteo (Route4me® en versión de prueba para las cabeceras departamentales y RouteXL® en versión gratuita para la distribución urbana), dibuja las rutas a seguir desde el punto de fabricación y almacenamiento en Cartago, y desde ahí, a todos los demás municipios del Valle del Cauca. Se tienen en cuenta los volúmenes de producto a transportar. Las rutas se organizan mensualmente y para cada una se calcula el tiempo total de recorridoPregradoIngeniero(a) Industria

Annual Report 2004: Econometric Institute

Annual Report (2004) of the Econometric Institute, Erasmus School of Economics, Erasmus University RotterdamThe year 2004 has been a year of extremes. The Erasmus School of Economics faced large deficits, and also the Econometric Institute had its share. For the first time in many years, temporary contracts could not be continued. Even some full time positions were cancelled or their requirements were changed. The new focus of the School (starting from 2005 onwards) dismissed a strong emphasis on mathematics and statistics as research areas, and it embraced areas as finance, marketing and economics in general. Much to our relief, it turned out that the focus of our Institute had already been diversified to these areas, so for many of us only few changes were required. On the other hand, our Institute kept its high level of teaching, culminating in being awarded the best programme in the country, and also many of its members kept their substantial research achievements at the usual top level. We had many visitors, reports and publications, and our conference participation was high. We also saw our first successful entries in the leading business and management journals, while maintaining a high level of contributions to the core journals in management science and econometrics. The year 2004 has been tough, for all of us, but without any doubt, I can say that we made it through. We have seen that even in hard times, the members of our Institute stand together, and there are many reasons to believe that we will continue to do so

A multi-agent system for a bus crew rescheduling system

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Unpredictable events (UE) are major factors that cause disruption to everyday bus operation. In the occurrence of UE, the main resources - crews and vehicles - are affected, and this leads to crew schedule disruption. One way to deal with the problem is crew rescheduling. Most of the current approaches are based on static schedules do not support rescheduling in a real-time scenario. They have the ability to reschedule but a new complete schedule is produced without concerning the real time situation. The mathematical approaches which are used by most scheduling packages have the ability to search for optimum or near optimum schedules but they are usually slow to produce results in real-time because they are computationally intensive when faced with complex situations. In practice, crew or bus rescheduling is managed manually, based on the supervisor's capabilities and experience in managing UE. However, manual rescheduling is complex, prone to error and not optimum, especially when dealing with many UE at the same time. This research proposes the CRSMAS (Crew Rescheduling System with Multi Agent System) approach as an alternative that may help supervisors to make quick rescheduling decisions by automating the crew rescheduling process. A Multi Agent System (MAS) is considered suitable to support this rescheduling because agents can dynamically adapt their behaviour to changing environments and they can find solutions quickly via negotiations and cooperation between them. To evaluate the CRSMAS, two types of experiment are carried out: Single Event and Multiple Events. The Single Event experiment is used to find characteristics of crew schedules that influence the crew rescheduling process while the Multiple Events experiment is used to test the capability of CRSMAS in dealing with numerous events that occur randomly. A wide range of simulation results, based on real-world data, are reported and analysed. Based on the experiment it is concluded that CRSMAS is suitable for automating the crew rescheduling process and capable of quick rescheduling whether facing single events or multiple events at the same time, the success of rescheduling is not only dependant on the tool but also to other factors such as the characteristics of crew schedules and the period of the UE, and one limitation of CRSMAS that was discovered is it cannot simulate different type of events at the same time. This limitation is because in different events there are different rules but, in Virtual World, agents can only negotiate with one set of rules at a time.Financial support was obtained from the Universiti Teknikal Malaysia Melaka (UTeM)