scholarly journals A Repeated Route-then-Schedule Approach to Coordinated Vehicle Platooning: Algorithms, Valid Inequalities and Computation

2021 ◽  
Author(s):  
Fengqiao Luo ◽  
Jeffrey Larson

In “A Repeated Route-then-Schedule Approach to Coordinated Vehicle Platooning: Algorithms, Valid Inequalities and Computation,” Luo and Larson propose a novel repeated route-then-schedule algorithmic framework to efficiently solve a complex vehicle routing and scheduling problem arising in the intelligent transportation system. The goal is to maximize the collective savings of a set of vehicles (especially heavy-duty vehicles) by utilizing the fact that platooning vehicles save energy due to reduced aerodynamic drag. In the algorithm, the original simultaneous route-and-schedule approach is decomposed into the routing stage and scheduling stage with a sophisticated learning-like feedback mechanism to update the presumed fuel cost for each vehicle traversing through each road segment. This leads to an iterative change of objective function in the routing problem and thereby changes the routes that are fed to the scheduling problem. This approach helps identify high-quality solution. The algorithmic framework leads to a very tight formulation of subproblems that can be solved in a timely manner.

Author(s):  
Juan Carlos Rivera ◽  
Victoria J. Zapata

Welfare community projects, mainly related to health care, are essential for the development of societies. For this reason, the optimization of its resources through methodologies that support decision making becomes of interest for all stakeholders in order to reach the target users. In Colombia, particularly in the city of Medellin, several social projects are being developed seeking to provide health and other social services to vulnerable populations. The purpose of this chapter is to deal with a real application of the home health care routing and scheduling problem (HHCRSP), in which a set of health professionals grouped by teams should visit a set of users geographically scatter over the city. Here, it is proposed a mixed integer linear model and a heuristic solution approach. The mathematical model is based on vehicle routing problem with pickups and deliveries (VRPPD) with additional features related with the specific application and geographical conditions.


Author(s):  
Ali Shafahi ◽  
Zhongxiang Wang ◽  
Ali Haghani

School bus planning is usually divided into routing and scheduling because of the complexity of solving them concurrently. However, the separation between these two steps may lead to worse solutions with higher overall costs than from solving them together. When the minimal number of trips in the routing problem is being determined, neglecting trip compatibility could increase the number of buses needed in the scheduling problem. This paper proposes a new formulation for the multischool homogeneous fleet routing problem that maximizes trip compatibility while minimizing total travel time. This plan incorporates the trip compatibility for the scheduling problem in the routing problem. A proposed heuristic algorithm for solving this problem decomposes the problem by schools. To compare the performance of the model with traditional routing problems, eight midsize data sets were generated. Importing the generated trips of the routing problems into the bus scheduling (blocking) problem shows that the proposed model can reduce the buses needed by up to 25%. A sensitivity analysis on coefficients of the model illustrates the effect of the weight of trip compatibility.


2020 ◽  
Vol 39 (6) ◽  
pp. 8125-8137
Author(s):  
Jackson J Christy ◽  
D Rekha ◽  
V Vijayakumar ◽  
Glaucio H.S. Carvalho

Vehicular Adhoc Networks (VANET) are thought-about as a mainstay in Intelligent Transportation System (ITS). For an efficient vehicular Adhoc network, broadcasting i.e. sharing a safety related message across all vehicles and infrastructure throughout the network is pivotal. Hence an efficient TDMA based MAC protocol for VANETs would serve the purpose of broadcast scheduling. At the same time, high mobility, influential traffic density, and an altering network topology makes it strenuous to form an efficient broadcast schedule. In this paper an evolutionary approach has been chosen to solve the broadcast scheduling problem in VANETs. The paper focusses on identifying an optimal solution with minimal TDMA frames and increased transmissions. These two parameters are the converging factor for the evolutionary algorithms employed. The proposed approach uses an Adaptive Discrete Firefly Algorithm (ADFA) for solving the Broadcast Scheduling Problem (BSP). The results are compared with traditional evolutionary approaches such as Genetic Algorithm and Cuckoo search algorithm. A mathematical analysis to find the probability of achieving a time slot is done using Markov Chain analysis.


1999 ◽  
Vol 31 (5) ◽  
pp. 395-406 ◽  
Author(s):  
HANIF D. SHERALI ◽  
SALEM MOHAMMED AL-YAKOOB ◽  
MERZA M. HASSAN

Energy ◽  
2021 ◽  
Vol 218 ◽  
pp. 119512
Author(s):  
Bin Ji ◽  
Binqiao Zhang ◽  
Samson S. Yu ◽  
Dezhi Zhang ◽  
Xiaohui Yuan

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