1,721,027 research outputs found
Optimization of Electric Bus Charging: Integrating Discrete Event Modeling in Public Transportation Systems
No full textThe transition to electric transportation is gaining more and more importance in the last years leading to new challenges to be addressed. A key role in this framework is represented by public transportation systems. This paper introduces a Discrete Event (DE) optimization model to optimize the charging scheduling of electric buses (EBs). By accounting for time tabling constraints, energy demand satisfaction, and the capability for simultaneous multi-socket charging, our model addresses the complexities inherent in managing EB fleets. Utilizing a periodic model to capture cyclical system behavior, we incorporate a detailed battery model reflecting nonlinear charging profiles to enhance accuracy in power requirement prediction and charging duration estimation Validation of our model is performed using real-world data, demonstrating its practical applicability. Copyright (C) 2024 The Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/
A user equilibrium model for electric vehicles: Joint traffic and energy demand assignment
No full textThe development of policies for sustainable development has led to an increase in electric vehicles (EVs). This has given rise to new problems, such as the location and sizing of charging stations over the considered traffic network. The solution of such problems requires the application of analysis techniques in order to predict the joint allocation of transportation and energy demands. In this paper, an approach is proposed that extends the User Equilibrium (UE) principle in order to determine, besides to the flow over the network links, the service requests from the drivers to the various service stations. The application of this method is preliminary for the statement of any problem related to the optimization of location and sizing of service stations. The proposed approach is applied to a case study in Genoa Municipality (Liguria Region)
Optimal decentralized routing policies for a class of queueing networks
No full textThe authors deal with optimal control problems of deterministic queuing networks. The class of networks considered is characterized by a single-class population of customers, each of which has to undergo the same sequence of operations. The network is composed of a number of identically structured islands, where a decisional node has to route incoming customers to one between two different servers. With reference to the minimization of the mean flow time in the overall network, the optimality of an informationally decentralized, threshold-type, and quasi-stationary policy is proved
SKED: An Integrated Decision Support System For Scheduling Problems
No full textThe aim of the decision support system SKED described in this paper is to provide a tool for automatic and manual scheduling. The scheduling model dealt with is characteristic of a large class of situations in manufacturing environments. The system utilizes a scheduler module based on a heuristic event-driven approach to find feasible solutions to the problem instances. Two modules allow the user to manage information about problems, and to examine and modify their solutions by means of an highly interactive graphical interface
Optimal routing of customers with general independent interarrival times in simple deterministic networks
No full textThreshold policies minimizing customer mean flow time in simple (out-tree) queueing networks
No full textStability of equilibrium points of traffic networks under constant input flows and splitting rates
No full textIn this paper, a multi-destination multi-source traffic network of a single kind of vehicles is considered. In particular, an analysis of the system model in steady-state conditions has been performed both as regards the input flows from the external and the splitting rates. It has been investigated under which conditions the system admits a unique asymptotically stable equilibrium point under Lyapunov's indirect method. The condition that will be described has a very clear physical significance and it represents an interesting insight about the way by which the unique asymptotically stable equilibrium point can be found analytically when the information about the external inputs, the values of the splitting rates, and the parameters characterizing each link in the network are made available
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