Locating Depots for Capacitated Vehicle Routing
DEFF Research Database (Denmark)
Gørtz, Inge Li; Nagarajan, Viswanath
2016-01-01
We study a location-routing problem in the context of capacitated vehicle routing. The input to the k-location capacitated vehicle routing problem (k-LocVRP) consists of a set of demand locations in a metric space and a fleet of k identical vehicles, each of capacity Q. The objective is to locate k...
The pyramidal capacitated vehicle routing problem
DEFF Research Database (Denmark)
Lysgaard, Jens
2010-01-01
This paper introduces the pyramidal capacitated vehicle routing problem (PCVRP) as a restricted version of the capacitated vehicle routing problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the pyramidal traveling salesman problem (PTSP). A pyramidal...
Locating Depots for Capacitated Vehicle Routing
DEFF Research Database (Denmark)
Gørtz, Inge Li; Nagarajan, Viswanath
2011-01-01
We study a location-routing problem in the context of capacitated vehicle routing. The input to k-LocVRP is a set of demand locations in a metric space and a fleet of k vehicles each of capacity Q. The objective is to locate k depots, one for each vehicle, and compute routes for the vehicles so...
The Pyramidal Capacitated Vehicle Routing Problem
DEFF Research Database (Denmark)
Lysgaard, Jens
This paper introduces the Pyramidal Capacitated Vehicle Routing Problem (PCVRP) as a restricted version of the Capacitated Vehicle Routing Problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the Pyramidal Traveling Salesman Problem (PTSP). A pyramidal...... found in many optimal solutions to CVRP instances. An optimal solution to the PCVRP may therefore be useful in itself as a heuristic solution to the CVRP. Further, an attempt can be made to find an even better CVRP solution by solving a TSP, possibly leading to a non-pyramidal route, for each...... of the routes in the PCVRP solution. This paper develops an exact branch-and-cut-and-price (BCP) algorithm for the PCVRP. At the pricing stage, elementary routes can be computed in pseudo-polynomial time in the PCVRP, unlike in the CVRP. We have therefore implemented pricing algorithms that generate only...
Fund allocation using capacitated vehicle routing problem
Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah Rozita; Darus, Maslina
2014-09-01
In investment fund allocation, it is unwise for an investor to distribute his fund into several assets simultaneously due to economic reasons. One solution is to allocate the fund into a particular asset at a time in a sequence that will either maximize returns or minimize risks depending on the investor's objective. The vehicle routing problem (VRP) provides an avenue to this issue. VRP answers the question on how to efficiently use the available fleet of vehicles to meet a given service demand, subjected to a set of operational requirements. This paper proposes an idea of using capacitated vehicle routing problem (CVRP) to optimize investment fund allocation by employing data of selected stocks in the FTSE Bursa Malaysia. Results suggest that CRVP can be applied to solve the issue of investment fund allocation and increase the investor's profit.
Locating Depots for Capacitated Vehicle Routing
Goertz, Inge Li
2011-01-01
We study a location-routing problem in the context of capacitated vehicle routing. The input is a set of demand locations in a metric space and a fleet of k vehicles each of capacity Q. The objective is to locate k depots, one for each vehicle, and compute routes for the vehicles so that all demands are satisfied and the total cost is minimized. Our main result is a constant-factor approximation algorithm for this problem. To achieve this result, we reduce to the k-median-forest problem, which generalizes both k-median and minimum spanning tree, and which might be of independent interest. We give a (3+c)-approximation algorithm for k-median-forest, which leads to a (12+c)-approximation algorithm for the above location-routing problem, for any constant c>0. The algorithm for k-median-forest is just t-swap local search, and we prove that it has locality gap 3+2/t; this generalizes the corresponding result known for k-median. Finally we consider the "non-uniform" k-median-forest problem which has different cost ...
OPTIMIZATION OF CAPACITATED VEHICLE ROUTING PROBLEM USING PSO
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S.R.VENKATESAN
2011-10-01
Full Text Available This paper presents solution techniques for Capacitated Vehicle Routing Problem (CVRP using metaheuristics. Capacitated Vehicle Routing Problem is divided into set of customers called cluster, and find optimum travel distance of vehicle route. The CVRP is a combinatorial optimization problem; particle swarm optimization(PSO technique is adapted in this paper to solve this problem. The main problem is divided into subprograms/clusters and each subprogram is treated as travelling salesman problem and solved by usingparticle swarm optimization techniques (PSO. This paper presents a sweep, Clark and wright algorithm to form the clusters. This model is then solved by using a particle swarm optimization (PSO method to find optimum travel distance of vehicle route. Our analysis suggests that the proposed model enables users to establish route to serve all given customers with minimum distance of vehicles and maximum capacity.
An Effective Hybrid Optimization Algorithm for Capacitated Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Capacitated vehicle routing problem (CVRP) is an important combinatorial optimization problem. However, it is quite difficult to achieve an optimal solution with the traditional optimization methods owing to the high computational complexity. A hybrid algorithm was developed to solve the problem, in which an artificial immune clonal algorithm (AICA) makes use of the global search ability to search the optimal results and simulated annealing (SA) algorithm employs certain probability to avoid becoming trapped in a local optimum. The results obtained from the computational study show that the proposed algorithm is a feasible and effective method for capacitated vehicle routing problem.
Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah@Rozita
2016-11-01
Two new methods adopted from methods commonly used in the field of transportation and logistics are proposed to solve a specific issue of investment allocation problem. Vehicle routing problem and capacitated vehicle routing methods are applied to optimize the fund allocation of a portfolio of investment assets. This is done by determining the sequence of the assets. As a result, total investment risk is minimized by this sequence.
Capacitated Vehicle Routing with Non-Uniform Speeds
DEFF Research Database (Denmark)
Gørtz, Inge Li; Molinaro, Marco; Nagarajan, Viswanath
2011-01-01
The capacitated vehicle routing problem (CVRP) [21] involves distributing (identical) items from a depot to a set of demand locations in the shortest possible time, using a single capacitated vehicle. We study a generalization of this problem to the setting of multiple vehicles having non-uniform...... vehicles having speeds {λ i } i = 1 k , the goal is to find a tour for each vehicle (starting and ending at r), so that every vertex is covered in some tour and the maximum completion time is minimized. This problem is precisely Heterogenous CVRP when vehicles are uncapacitated. The presence of non-uniform...... the introduction of a new approximate MST construction called Level-Prim, which is related to Light Approximate Shortest-path Trees [18]. The last component of our algorithm involves partitioning the Level-Prim tree and matching the resulting parts to vehicles. This decomposition is more subtle than usual since...
Capacitated Vehicle Routing with Non-Uniform Speeds
Gortz, Inge Li; Nagarajan, Viswanath; Ravi, R
2010-01-01
The capacitated vehicle routing problem (CVRP) involves distributing (identical) items from a depot to a set of demand locations, using a single capacitated vehicle. We study a generalization of this problem to the setting of multiple vehicles having non-uniform speeds (that we call Heterogenous CVRP), and present a constant-factor approximation algorithm. The technical heart of our result lies in achieving a constant approximation to the following TSP variant (called Heterogenous TSP). Given a metric denoting distances between vertices, a depot r containing k vehicles with possibly different speeds, the goal is to find a tour for each vehicle (starting and ending at r), so that every vertex is covered in some tour and the maximum completion time is minimized. This problem is precisely Heterogenous CVRP when vehicles are uncapacitated. The presence of non-uniform speeds introduces difficulties for employing standard tour-splitting techniques. In order to get a better understanding of this technique in our con...
A novel heuristic algorithm for capacitated vehicle routing problem
Kır, Sena; Yazgan, Harun Reşit; Tüncel, Emre
2017-02-01
The vehicle routing problem with the capacity constraints was considered in this paper. It is quite difficult to achieve an optimal solution with traditional optimization methods by reason of the high computational complexity for large-scale problems. Consequently, new heuristic or metaheuristic approaches have been developed to solve this problem. In this paper, we constructed a new heuristic algorithm based on the tabu search and adaptive large neighborhood search (ALNS) with several specifically designed operators and features to solve the capacitated vehicle routing problem (CVRP). The effectiveness of the proposed algorithm was illustrated on the benchmark problems. The algorithm provides a better performance on large-scaled instances and gained advantage in terms of CPU time. In addition, we solved a real-life CVRP using the proposed algorithm and found the encouraging results by comparison with the current situation that the company is in.
A branch-and-cut-and-price algorithm for the cumulative capacitated vehicle routing problem
DEFF Research Database (Denmark)
Wøhlk, Sanne; Lysgaard, Jens
2014-01-01
The paper considers the Cumulative Capacitated Vehicle Routing Problem (CCVRP), which is a variation of the well-known Capacitated Vehicle Routing Problem (CVRP). In this problem, the traditional objective of minimizing total distance or time traveled by the vehicles is replaced by minimizing...
Variable neighbourhood simulated annealing algorithm for capacitated vehicle routing problems
Xiao, Yiyong; Zhao, Qiuhong; Kaku, Ikou; Mladenovic, Nenad
2014-04-01
This article presents the variable neighbourhood simulated annealing (VNSA) algorithm, a variant of the variable neighbourhood search (VNS) combined with simulated annealing (SA), for efficiently solving capacitated vehicle routing problems (CVRPs). In the new algorithm, the deterministic 'Move or not' criterion of the original VNS algorithm regarding the incumbent replacement is replaced by an SA probability, and the neighbourhood shifting of the original VNS (from near to far by k← k+1) is replaced by a neighbourhood shaking procedure following a specified rule. The geographical neighbourhood structure is introduced in constructing the neighbourhood structures for the CVRP of the string model. The proposed algorithm is tested against 39 well-known benchmark CVRP instances of different scales (small/middle, large, very large). The results show that the VNSA algorithm outperforms most existing algorithms in terms of computational effectiveness and efficiency, showing good performance in solving large and very large CVRPs.
Ant Colony Optimization for Capacitated Vehicle Routing Problem
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H. V. Seow
2012-01-01
Full Text Available Problem statement: The Capacitated Vehicle Routing Problem (CVRP is a well-known combinatorial optimization problem which is concerned with the distribution of goods between the depot and customers. It is of economic importance to businesses as approximately 10-20% of the final cost of the goods is contributed by the transportation process. Approach: This problem was tackled using an Ant Colony Optimization (ACO combined with heuristic approaches that act as the route improvement strategies. The proposed ACO utilized a pheromone evaporation procedure of standard ant algorithm in order to introduce an evaporation rate that depends on the solutions found by the artificial ants. Results: Computational experiments were conducted on benchmark data set and the results obtained from the proposed algorithms shown that the application of combination of two different heuristics in the ACO had the capability to improve the ants solutions better than ACO embedded with only one heuristic. Conclusion: ACO with swap and 3-opt heuristic has the capability to tackle the CVRP with satisfactory solution quality and run time. It is a viable alternative for solving the CVRP.
A branch-and-cut algorithm for the capacitated open vehicle routing problem
DEFF Research Database (Denmark)
Letchford, A.N.; Lysgaard, Jens; Eglese, R.W.
2007-01-01
In open vehicle routing problems, the vehicles are not required to return to the depot after completing service. In this paper, we present the first exact optimization algorithm for the open version of the well-known capacitated vehicle routing problem (CVRP). The algorithm is based on branch-and...
Damanik, Donna
2016-01-01
Model to choose vehicle route is known as Vehicle Routing Problem (VRP). VRP is related to optimal routing problem that involve more than one vehicle of each capacity to serve costumer’s demand. Capacitated Vehicle Routing Problem is one of VRP form which each of vehicle has finite capacity. Solution in this research use Clarke and Wright’s Savings Algorithm. This algorithm may get a route depand to vehicle capacity and customer’s demand. Data that use in this research is di...
Capacitated vehicle routing problem with sequence-based pallet loading and axle weight constraints
2016-01-01
In this paper, we introduce and study the capacitated vehicle routing problem with sequence-based pallet loading and axle weight constraints. To the best of our knowledge, it is the first time that axle weight restrictions are incorporated in a vehicle routing model. The aim of this paper is to demonstrate that incorporating axle weight restrictions in a vehicle routing model is possible and necessary for a feasible route planning. Axle weight limits impose a great challenge for transportatio...
Hybrid discrete particle swarm optimization algorithm for capacitated vehicle routing problem
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Capacitated vehicle routing problem (CVRP) is an NP-hard problem. For large-scale problems, it is quite difficult to achieve an optimal solution with traditional optimization methods due to the high computational complexity. A new hybrid approximation algorithm is developed in this work to solve the problem. In the hybrid algorithm, discrete particle swarm optimization (DPSO) combines global search and local search to search for the optimal results and simulated annealing (SA) uses certain probability to avoid being trapped in a local optimum. The computational study showed that the proposed algorithm is a feasible and effective approach for capacitated vehicle routing problem, especially for large scale problems.
Optimization of Capacitated Vehicle Routing Problem by Nested Particle Swarm Optimization
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Karuppusamy Kanthavel
2011-01-01
Full Text Available Problem statement: Vehicle routing problem determines the optimum route for each vehicle as a sequence of visiting cities. The problem has been defined as NP-hard and exact solution is relatively difficult to achieve for real time large scale models. Though several attempts to solve the problem were made in the literature, new approaches may be tried to solve the problem to further reduce computational efforts. Approach: In this context this study focuses on maximum utilization of loading capacity and determines the optimum set of vehicle routes for Capacitated Vehicle Routing Problem (CVRP by a Nested Particle Swarm Optimization (NPSO technique. The algorithm is implemented as Master PSO and slave PSO for the identification of candidate list and route sequence in nested form to optimize the model. Results: Benchmarking data set of capacitated vehicle routing is considered for the evaluations. The total distance of set vehicle route obtained by the new approach is compared with the best known solution and other existing techniques. Conclusions/Recommendations: The NPSO produces significant results and computational performance than the existing PSO algorithms. This newly proposed NPSO algorithm develops the vehicle schedule without any local optimization technique.
An Artificial Bee Colony Algorithm for the Capacitated Vehicle Routing Problem
DEFF Research Database (Denmark)
Szeto, W.Y.; Wu, Yongzhong; Ho, Sin C.
This paper introduces an artificial bee colony heuristic for the capacitated vehicle routing problem. The artificial bee colony heuristic is a swarm-based heuristic, which mimics the foraging behavior of a honey bee swarm. The performance of the heuristic is evaluated on two sets of benchmark ins...
An artificial bee colony algorithm for the capacitated vehicle routing problem
DEFF Research Database (Denmark)
Szeto, W.Y.; Wu, Yongzhong; Ho, Sin C.
2011-01-01
This paper introduces an artificial bee colony heuristic for solving the capacitated vehicle routing problem. The artificial bee colony heuristic is a swarm-based heuristic, which mimics the foraging behavior of a honey bee swarm. An enhanced version of the artificial bee colony heuristic is also...
A branch-and-cut algorithm for the symmetric two-echelon capacitated vehicle routing problem
DEFF Research Database (Denmark)
Jepsen, Mads Kehlet; Spoorendonk, Simon; Røpke, Stefan
2013-01-01
This paper presents an exact method for solving the symmetric two-echelon capacitated vehicle routing problem, a transportation problem concerned with the distribution of goods from a depot to a set of customers through a set of satellite locations. The presented method is based on an edge flow...
A branch-and-price algorithm for the capacitated vehicle routing problem with stochastic demands
DEFF Research Database (Denmark)
Christiansen, Christian Holk; Lysgaard, Jens
2007-01-01
This article introduces a new exact algorithm for the Capacitated Vehicle Routing Problem with Stochastic Demands (CVRPSD). The CVRPSD can be formulated as a Set Partitioning Problem and it is shown that the associated column generation subproblem can be solved using a dynamic programming scheme...
Davendra, Donald; Zelinka, Ivan; Senkerik, Roman; Jasek, Roman; Bialic-Davendra, Magdalena
2012-11-01
One of the new emerging application strategies for optimization is the hybridization of existing metaheuristics. The research combines the unique paradigms of solution space sampling of SOMA and memory retention capabilities of Scatter Search for the task of capacitated vehicle routing problem. The new hybrid heuristic is tested on the Taillard sets and obtains good results.
A Food Chain Algorithm for Capacitated Vehicle Routing Problem with Recycling in Reverse Logistics
Song, Qiang; Gao, Xuexia; Santos, Emmanuel T.
2015-12-01
This paper introduces the capacitated vehicle routing problem with recycling in reverse logistics, and designs a food chain algorithm for it. Some illustrative examples are selected to conduct simulation and comparison. Numerical results show that the performance of the food chain algorithm is better than the genetic algorithm, particle swarm optimization as well as quantum evolutionary algorithm.
A Learning Automata Based Algorithm For Solving Capacitated Vehicle Routing Problem
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Mir Mohammad Alipour
2012-03-01
Full Text Available This paper presents an approximate algorithm based on distributed learning automata for solving capacitated vehicle routing problem. The vehicle routing problem (VRP is an NP-hard problem and capacitated vehicle routing problem variant (CVRP is considered here. This problem is one of the NP-hard problems and for this reason many approximate algorithms have been designed for solving it. Distributed learning automata that is a general searching tool and is a solving tool for variety of NP-complete problems, is used to solve this problem and tested on fourteen benchmark problems. Our results were compared to the best known results. The results of comparison have shown the efficiency of the proposed algorithm.
Developing a Direct Search Algorithm for Solving the Capacitated Open Vehicle Routing Problem
Simbolon, Hotman
2011-06-01
In open vehicle routing problems, the vehicles are not required to return to the depot after completing service. In this paper, we present the first exact optimization algorithm for the open version of the well-known capacitated vehicle routing problem (CVRP). The strategy of releasing nonbasic variables from their bounds, combined with the "active constraint" method and the notion of superbasics, has been developed for efficiently requirements; this strategy is used to force the appropriate non-integer basic variables to move to their neighborhood integer points. A study of criteria for choosing a nonbasic variable to work with in the integerizing strategy has also been made.
Sarwono, A. A.; Ai, T. J.; Wigati, S. S.
2017-01-01
Vehicle Routing Problem (VRP) is a method for determining the optimal route of vehicles in order to serve customers starting from depot. Combination of the two most important problems in distribution logistics, which is called the two dimensional loading vehicle routing problem, is considered in this paper. This problem combines the loading of the freight into the vehicles and the successive routing of the vehicles along the route. Moreover, an additional feature of last-in-first-out loading sequencesis also considered. In the sequential two dimensional loading capacitated vehicle routing problem (sequential 2L-CVRP), the loading must be compatible with the trip sequence: when the vehicle arrives at a customer i, there must be no obstacle (items for other customers) between the item of i and the loading door (rear part) of the vehicle. In other words, it is not necessary to move non-i’s items whenever the unloading process of the items of i. According with aforementioned conditions, a program to solve sequential 2L-CVRP is required. A nearest neighbor algorithm for solving the routing problem is presented, in which the loading component of the problem is solved through a collection of 5 packing heuristics.
Using Grey Wolf Algorithm to Solve the Capacitated Vehicle Routing Problem
Korayem, L.; Khorsid, M.; Kassem, S. S.
2015-05-01
The capacitated vehicle routing problem (CVRP) is a class of the vehicle routing problems (VRPs). In CVRP a set of identical vehicles having fixed capacities are required to fulfill customers' demands for a single commodity. The main objective is to minimize the total cost or distance traveled by the vehicles while satisfying a number of constraints, such as: the capacity constraint of each vehicle, logical flow constraints, etc. One of the methods employed in solving the CVRP is the cluster-first route-second method. It is a technique based on grouping of customers into a number of clusters, where each cluster is served by one vehicle. Once clusters are formed, a route determining the best sequence to visit customers is established within each cluster. The recently bio-inspired grey wolf optimizer (GWO), introduced in 2014, has proven to be efficient in solving unconstrained, as well as, constrained optimization problems. In the current research, our main contributions are: combining GWO with the traditional K-means clustering algorithm to generate the ‘K-GWO’ algorithm, deriving a capacitated version of the K-GWO algorithm by incorporating a capacity constraint into the aforementioned algorithm, and finally, developing 2 new clustering heuristics. The resulting algorithm is used in the clustering phase of the cluster-first route-second method to solve the CVR problem. The algorithm is tested on a number of benchmark problems with encouraging results.
Solving the Capacitated Vehicle Routing Problem Based on Improved Ant-clustering Algorithm
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Zhang Jiashan
2015-01-01
Full Text Available The capacitated vehicle routing problems (CVRP are NP-hard. Most approaches can solve small-scale case studies to optimality. Furthermore, they are time-consuming. To overcome the limitation, this paper presents a novel three-phase heuristic approach for the capacitated vehicle routing problem. The first phase aims to identify sets of cost-effective feasible clusters through an improved ant-clustering algorithm, in which the adaptive strategy is adopted. The second phase assigns clusters to vehicles and sequences them on each tour. The third phase orders nodes within clusters for every tour and genetic algorithm is used to order nodes within clusters. The simulation indicates the algorithm attains high quality results in a short time.
A new approach on auxiliary vehicle assignment in capacitated location routing problem
Bashiri, Mahdi; Rasoulinejad, Zeinab; Fallahzade, Ehsan
2016-03-01
The location routing problem (LRP) considers locating depots and vehicle routing decisions simultaneously. In classic LRP the number of customers in each route depends on the capacity of the vehicle. In this paper a capacitated LRP model with auxiliary vehicle assignment is presented in which the length of each route is not restricted by main vehicle capacity. Two kinds of vehicles are considered: main vehicles with higher capacity and fixed cost and auxiliary vehicles with lower capacity and fixed cost. The auxiliary vehicles can be added to the transportation system as an alternative strategy to cover the capacity limitations and they are just used to transfer goods from depots to vehicles and cannot serve the customers by themselves. To show the applicability of the proposed model, some numerical examples derived from the well-known instances are used. Moreover the model has been solved by some meta-heuristics for large sized instances. The results show the efficiency of the proposed model and the solution approach, considering the classic model and the exact solution approach, respectively.
A Hybrid Algorithm Based on ACO and PSO for Capacitated Vehicle Routing Problems
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Yucheng Kao
2012-01-01
Full Text Available The vehicle routing problem (VRP is a well-known combinatorial optimization problem. It has been studied for several decades because finding effective vehicle routes is an important issue of logistic management. This paper proposes a new hybrid algorithm based on two main swarm intelligence (SI approaches, ant colony optimization (ACO and particle swarm optimization (PSO, for solving capacitated vehicle routing problems (CVRPs. In the proposed algorithm, each artificial ant, like a particle in PSO, is allowed to memorize the best solution ever found. After solution construction, only elite ants can update pheromone according to their own best-so-far solutions. Moreover, a pheromone disturbance method is embedded into the ACO framework to overcome the problem of pheromone stagnation. Two sets of benchmark problems were selected to test the performance of the proposed algorithm. The computational results show that the proposed algorithm performs well in comparison with existing swarm intelligence approaches.
A Column Generation Approach to the Capacitated Vehicle Routing Problem with Stochastic Demands
DEFF Research Database (Denmark)
Christiansen, Christian Holk; Lysgaard, Jens
In this article we introduce a new exact solution approach to the Capacitated Vehicle Routing Problem with Stochastic Demands (CVRPSD). In particular, we consider the case where all customer demands are distributed independently and where each customer's demand follows a Poisson distribution...... approach we have embedded this column generation scheme in a branch-and-price algorithm. Computational experiments on a large set of test instances show promising results....
A quasi-polynomial time approximation scheme for Euclidean capacitated vehicle routing
Das, Aparna
2008-01-01
In the capacitated vehicle routing problem, introduced by Dantzig and Ramser in 1959, we are given the locations of n customers and a depot, along with a vehicle of capacity k, and wish to find a minimum length collection of tours, each starting from the depot and visiting at most k customers, whose union covers all the customers. We give a quasi-polynomial time approximation scheme for the setting where the customers and the depot are on the plane, and distances are given by the Euclidean metric.
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Kui-Ting CHEN
2015-12-01
Full Text Available Capacitated vehicle routing problem with pickups and deliveries (CVRPPD is one of the most challenging combinatorial optimization problems which include goods delivery/pickup optimization, vehicle number optimization, routing path optimization and transportation cost minimization. The conventional particle swarm optimization (PSO is difficult to find an optimal solution of the CVRPPD due to its simple search strategy. A PSO with adaptive multi-swarm strategy (AMSPSO is proposed to solve the CVRPPD in this paper. The proposed AMSPSO employs multiple PSO algorithms and an adaptive algorithm with punishment mechanism to search the optimal solution, which can deal with large-scale optimization problems. The simulation results prove that the proposed AMSPSO can solve the CVRPPD with the least number of vehicles and less transportation cost, simultaneously.
Lamdjaya, T.; Jobiliong, E.
2017-01-01
PT Anugrah Citra Boga is a food processing industry that produces meatballs as their main product. The distribution system of the products must be considered, because it needs to be more efficient in order to reduce the shipment cost. The purpose of this research is to optimize the distribution time by simulating the distribution channels with capacitated vehicle routing problem method. Firstly, the distribution route is observed in order to calculate the average speed, time capacity and shipping costs. Then build the model using AIMMS software. A few things that are required to simulate the model are customer locations, distances, and the process time. Finally, compare the total distribution cost obtained by the simulation and the historical data. It concludes that the company can reduce the shipping cost around 4.1% or Rp 529,800 per month. By using this model, the utilization rate can be more optimal. The current value for the first vehicle is 104.6% and after the simulation it becomes 88.6%. Meanwhile, the utilization rate of the second vehicle is increase from 59.8% to 74.1%. The simulation model is able to produce the optimal shipping route with time restriction, vehicle capacity, and amount of vehicle.
A new formulation for the 2-echelon capacitated vehicle routing problem
DEFF Research Database (Denmark)
Jepsen, Mads Kehlet; Røpke, Stefan; Spoorendonk, Simon
The 2-echelon capacitated vehicle routing problem (2E-CVRP) is a transportation and distribution problem where goods are transported from a depot to a set of customers possible via optional satellite facilities. The 2E-CVRP is relevant in city-logistic applications where legal restrictions make...... it infeasible to use large trucks within the center of large cities. We propose a new mathematical formulation for the 2E-CVRP with much fewer variables than the previously proposed but with several constraint sets of exponential size. The strength of the model is implied by the facts that many cutting planes...
Robust Branch-and-Cut-and-Price for the Capacitated Vehicle Routing Problem
DEFF Research Database (Denmark)
Fukasawa, R.; Longo, H.; Lysgaard, Jens
2006-01-01
The best exact algorithms for the Capacitated Vehicle Routing Problem (CVRP) have been based on either branch-and-cut or Lagrangean relaxation/column generation. This paper presents an algorithm that combines both approaches: it works over the intersection of two polytopes, one associated...... with a traditional Lagrangean relaxation over q-routes, the other defined by bound, degree and capacity constraints. This is equivalent to a linear program with exponentially many variables and constraints that can lead to lower bounds that are superior to those given by previous methods. The resulting branch......-and-cut-and-price algorithm can solve to optimality all instances from the literature with up to 135 vertices. This more than doubles the size of the instances that can be consistently solved....
Approximability of the d-dimensional Euclidean capacitated vehicle routing problem
Khachay, Michael; Dubinin, Roman
2016-10-01
Capacitated Vehicle Routing Problem (CVRP) is the well known intractable combinatorial optimization problem, which remains NP-hard even in the Euclidean plane. Since the introduction of this problem in the middle of the 20th century, many researchers were involved into the study of its approximability. Most of the results obtained in this field are based on the well known Iterated Tour Partition heuristic proposed by M. Haimovich and A. Rinnoy Kan in their celebrated paper, where they construct the first Polynomial Time Approximation Scheme (PTAS) for the single depot CVRP in ℝ2. For decades, this result was extended by many authors to numerous useful modifications of the problem taking into account multiple depots, pick up and delivery options, time window restrictions, etc. But, to the best of our knowledge, almost none of these results go beyond the Euclidean plane. In this paper, we try to bridge this gap and propose a EPTAS for the Euclidean CVRP for any fixed dimension.
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Ligang Cui
2013-01-01
Full Text Available The capacitated vehicle routing problem (CVRP is the most classical vehicle routing problem (VRP; many solution techniques are proposed to find its better answer. In this paper, a new improved quantum evolution algorithm (IQEA with a mixed local search procedure is proposed for solving CVRPs. First, an IQEA with a double chain quantum chromosome, new quantum rotation schemes, and self-adaptive quantum Not gate is constructed to initialize and generate feasible solutions. Then, to further strengthen IQEA's searching ability, three local search procedures 1-1 exchange, 1-0 exchange, and 2-OPT, are adopted. Experiments on a small case have been conducted to analyze the sensitivity of main parameters and compare the performances of the IQEA with different local search strategies. Together with results from the testing of CVRP benchmarks, the superiorities of the proposed algorithm over the PSO, SR-1, and SR-2 have been demonstrated. At last, a profound analysis of the experimental results is presented and some suggestions on future researches are given.
Computational results with a branch and cut code for the capacitated vehicle routing problem
Energy Technology Data Exchange (ETDEWEB)
Augerat, P.; Naddef, D. [Institut National Polytechnique, 38 - Grenoble (France); Belenguer, J.M.; Benavent, E.; Corberan, A. [Valencia Univ. (Spain); Rinaldi, G. [Consiglio Nazionale delle Ricerche, Rome (Italy)
1995-09-01
The Capacitated Vehicle Routing Problem (CVRP) we consider in this paper consists in the optimization of the distribution of goods from a single depot to a given set of customers with known demand using a given number of vehicles of fixed capacity. There are many practical routing applications in the public sector such as school bus routing, pick up and mail delivery, and in the private sector such as the dispatching of delivery trucks. We present a Branch and Cut algorithm to solve the CVRP which is based in the partial polyhedral description of the corresponding polytope. The valid inequalities used in our method can ne found in Cornuejols and Harche (1993), Harche and Rinaldi (1991) and in Augerat and Pochet (1995). We concentrated mainly on the design of separation procedures for several classes of valid inequalities. The capacity constraints (generalized sub-tour eliminations inequalities) happen to play a crucial role in the development of a cutting plane algorithm for the CVRP. A large number of separation heuristics have been implemented and compared for these inequalities. There has been also implemented heuristic separation algorithms for other classes of valid inequalities that also lead to significant improvements: comb and extended comb inequalities, generalized capacity inequalities and hypo-tour inequalities. The resulting cutting plane algorithm has been applied to a set of instances taken from the literature and the lower bounds obtained are better than the ones previously known. Some branching strategies have been implemented to develop a Branch an Cut algorithm that has been able to solve large CVRP instances, some of them which had never been solved before. (authors). 32 refs., 3 figs., 10 tabs.
A Problem-Reduction Evolutionary Algorithm for Solving the Capacitated Vehicle Routing Problem
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Wanfeng Liu
2015-01-01
Full Text Available Assessment of the components of a solution helps provide useful information for an optimization problem. This paper presents a new population-based problem-reduction evolutionary algorithm (PREA based on the solution components assessment. An individual solution is regarded as being constructed by basic elements, and the concept of acceptability is introduced to evaluate them. The PREA consists of a searching phase and an evaluation phase. The acceptability of basic elements is calculated in the evaluation phase and passed to the searching phase. In the searching phase, for each individual solution, the original optimization problem is reduced to a new smaller-size problem. With the evolution of the algorithm, the number of common basic elements in the population increases until all individual solutions are exactly the same which is supposed to be the near-optimal solution of the optimization problem. The new algorithm is applied to a large variety of capacitated vehicle routing problems (CVRP with customers up to nearly 500. Experimental results show that the proposed algorithm has the advantages of fast convergence and robustness in solution quality over the comparative algorithms.
Directory of Open Access Journals (Sweden)
Alberto Ochoa-Ortíz
2015-01-01
Full Text Available El problema de ruteo de vehículos bajo las limitaciones de capacidad y basado en computación ubicua desde una perspectiva relacionada con PSS (Producto-Servicio de Sistemas para desarrollar configuraciones para el transporte urbano de mercancías es abordado. Éste trabajo considera las especificidades de la logística urbana bajo un contexto de mercados emergentes. En este caso, involucra: i bajas competencias logísticas de los tomadores de decisiones; ii la limitada disponibilidad de datos; y iii restringido acceso a tecnología de alto desempeño para calcular rutas de transporte óptimas. Por lo tanto, se propone el uso de un software libre que proporciona soluciones de bajo costo (en tiempo y recursos. El artículo muestra la aplicación de los resultados de una herramienta de software basado en la Teoría de Grafos utilizado para analizar y resolver un CVRP (Capacitated Vehicle Routing Problem. Se utilizó el caso de una empresa local de distribución de alimentos situada en una gran ciudad de México. Sobre la base de una flora de vehículos pequeños, todos con las mismas especificaciones técnicas y una capacidad de carga comparable.
An optimization algorithm for a capacitated vehicle routing problem with time windows
Indian Academy of Sciences (India)
PINAR KIRCI
2016-05-01
In this paper, vehicle routing problem (VRP) with time windows and real world constraints are considered as a real-world application on google maps. Also, tabu search is used and Hopfield neural networks is utilized. Basic constraints consist of customer demands, time windows, vehicle speed, vehicle capacity andworking hours. Recently, cost and on-time delivery are the most important actors in logistics. Thus, the logistic applications attract attention of companies. In logistic management, determining the locations of delivery points and deciding the path are the vital components that should be considered. Deciding the paths of vehicles provides companies to use their vehicles efficiently. And with utilizing optimized paths, big amounts of cost and time savings will be gained. The main aim of the work is providing the best path according to the needs of the customers, minimizing the costs with utilizing the VRP and presenting an application for companies that need logistic management. To compare the results, simulated annealing is used on special scenarios. And t-test is performed in the study for the visited path in km with p-value of 0.05.
A branch-and-cut-and-price algorithm for the mixed capacitated general routing problem
DEFF Research Database (Denmark)
Bach, Lukas; Wøhlk, Sanne; Lysgaard, Jens
2016-01-01
In this paper, we consider the Mixed Capacitated General Routing Problem which is a combination of the Capacitated Vehicle Routing Problem and the Capacitated Arc Routing Problem. The problem is also known as the Node, Edge, and Arc Routing Problem. We propose a Branch-and-Cut-and-Price algorithm...
An Approximation Algorithm for the Capacitated Arc Routing Problem
DEFF Research Database (Denmark)
Wøhlk, Sanne
2008-01-01
In this paper we consider approximation of the Capacitated Arc Routing Problem, which is the problem of servicing a set of edges in a graph using a fleet of capacity constrained vehicles. We present a 7/2 - 3/W-approximation algorithm for the problem and prove that this algorithm outperforms...
Cumulative Vehicle Routing Problems
Kara, &#;mdat; Kara, Bahar Yeti&#;; Yeti&#;, M. Kadri
2008-01-01
This paper proposes a new objective function and corresponding formulations for the vehicle routing problem. The new cost function defined as the product of the distance of the arc and the flow on that arc. We call a vehicle routing problem with this new objective function as the Cumulative Vehicle Routing Problem (CumVRP). Integer programming formulations with O(n2) binary variables and O(n2) constraints are developed for both collection and delivery cases. We show that the CumVRP is a gener...
The Consistent Vehicle Routing Problem
Energy Technology Data Exchange (ETDEWEB)
Groer, Christopher S [ORNL; Golden, Bruce [University of Maryland; Edward, Wasil [American University
2009-01-01
In the small package shipping industry (as in other industries), companies try to differentiate themselves by providing high levels of customer service. This can be accomplished in several ways, including online tracking of packages, ensuring on-time delivery, and offering residential pickups. Some companies want their drivers to develop relationships with customers on a route and have the same drivers visit the same customers at roughly the same time on each day that the customers need service. These service requirements, together with traditional constraints on vehicle capacity and route length, define a variant of the classical capacitated vehicle routing problem, which we call the consistent VRP (ConVRP). In this paper, we formulate the problem as a mixed-integer program and develop an algorithm to solve the ConVRP that is based on the record-to-record travel algorithm. We compare the performance of our algorithm to the optimal mixed-integer program solutions for a set of small problems and then apply our algorithm to five simulated data sets with 1,000 customers and a real-world data set with more than 3,700 customers. We provide a technique for generating ConVRP benchmark problems from vehicle routing problem instances given in the literature and provide our solutions to these instances. The solutions produced by our algorithm on all problems do a very good job of meeting customer service objectives with routes that have a low total travel time.
Capacitated arc routing problem and its extensions in waste collection
Energy Technology Data Exchange (ETDEWEB)
Fadzli, Mohammad; Najwa, Nurul [Institut Matematik Kejuruteraan, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia); Luis, Martino [Othman Yeop Abdullah Graduate School of Business, Universiti Utara Malaysia, 06010 Sintok, Kedah (Malaysia)
2015-05-15
Capacitated arc routing problem (CARP) is the youngest generation of graph theory that focuses on solving the edge/arc routing for optimality. Since many years, operational research devoted to CARP counterpart, known as vehicle routing problem (VRP), which does not fit to several real cases such like waste collection problem and road maintenance. In this paper, we highlighted several extensions of capacitated arc routing problem (CARP) that represents the real-life problem of vehicle operation in waste collection. By purpose, CARP is designed to find a set of routes for vehicles that satisfies all pre-setting constraints in such that all vehicles must start and end at a depot, service a set of demands on edges (or arcs) exactly once without exceeding the capacity, thus the total fleet cost is minimized. We also addressed the differentiation between CARP and VRP in waste collection. Several issues have been discussed including stochastic demands and time window problems in order to show the complexity and importance of CARP in the related industry. A mathematical model of CARP and its new version is presented by considering several factors such like delivery cost, lateness penalty and delivery time.
Capacitated arc routing problem and its extensions in waste collection
Fadzli, Mohammad; Najwa, Nurul; Luis, Martino
2015-05-01
Capacitated arc routing problem (CARP) is the youngest generation of graph theory that focuses on solving the edge/arc routing for optimality. Since many years, operational research devoted to CARP counterpart, known as vehicle routing problem (VRP), which does not fit to several real cases such like waste collection problem and road maintenance. In this paper, we highlighted several extensions of capacitated arc routing problem (CARP) that represents the real-life problem of vehicle operation in waste collection. By purpose, CARP is designed to find a set of routes for vehicles that satisfies all pre-setting constraints in such that all vehicles must start and end at a depot, service a set of demands on edges (or arcs) exactly once without exceeding the capacity, thus the total fleet cost is minimized. We also addressed the differentiation between CARP and VRP in waste collection. Several issues have been discussed including stochastic demands and time window problems in order to show the complexity and importance of CARP in the related industry. A mathematical model of CARP and its new version is presented by considering several factors such like delivery cost, lateness penalty and delivery time.
Vehicle Routing Problem Models
Directory of Open Access Journals (Sweden)
Tonči Carić
2004-01-01
Full Text Available The Vehicle Routing Problem cannot always be solved exactly,so that in actual application this problem is solved heuristically.The work describes the concept of several concrete VRPmodels with simplified initial conditions (all vehicles are ofequal capacity and start from a single warehouse, suitable tosolve problems in cases with up to 50 users.
A Memetic Algorithm for the Capacitated Location-Routing Problem
Directory of Open Access Journals (Sweden)
Laila KECHMANE
2016-06-01
Full Text Available In this paper, a hybrid genetic algorithm is proposed to solve a Capacitated Location-Routing Problem. The objective is to minimize the total cost of the distribution in a network composed of depots and customers, both depots and vehicles have limited capacities, each depot has a homogenous vehicle fleet and customers’ demands are known and must be satisfied. Solving this problem involves making strategic decisions such as the location of depots, as well as tactical and operational decisions which include assigning customers to the opened depots and organization of the vehicle routing. To evaluate the performance of the proposed algorithm, its results are compared to those obtained by a greedy randomized adaptive search procedure, computational results shows that the algorithm gave good quality solutions.
Institute of Scientific and Technical Information of China (English)
陈可嘉; 于先康
2013-01-01
The capacitated vehicle routing problem in reverse logistics is introduced. The food chain algorithm for the capacitated vehicle routing problem in reverse logistics is designed. A representative example is selected to conduct simulation and comparison. Numerical results show that the performance of the food chain algorithm is better than genetic algorithm, particle swarm optimi-zation as well as quantum evolutionary algorithm.%介绍了有能力约束逆向物流回收车辆路径问题，设计了求解有能力约束逆向物流回收车辆路径问题的食物链算法；选取文献典型算例进行了仿真求解及比较分析，结果表明设计的食物链算法性能优于遗传算法、粒子群算法和量子进化算法。
Periodic capacitated arc routing problem applied in a real context
Directory of Open Access Journals (Sweden)
Guilherme Vinicyus Batista
2015-09-01
Full Text Available A good inspection and maintenance planning in railways is essential to ensure the flow of trains and avoid possible accidents. This inspection should be performed periodically by vehicle traveling on rails collecting data and identifying gaps that need to be corrected. The aim of this paper is to present a mathematical model based on binary linear programming, capable of solving this problem, which is a real application of Periodic Capacitated Arc Routing Problem (PCARP. In the PCARP each arc of a network has a demand over a well-defined time horizon and routes must be created for each car so that it covers all the requests in the best way possible without exceeding the vehicles capacity at service. The proposed application has different characteristics to those already proposed in the literature because the vehicle does not need to come back to the depot at the end of the day and the service can be delayed if necessary. The result is satisfactory, covering the demands with a synchronized movement of vehicles.
General heuristics algorithms for solving capacitated arc routing problem
Fadzli, Mohammad; Najwa, Nurul; Masran, Hafiz
2015-05-01
In this paper, we try to determine the near-optimum solution for the capacitated arc routing problem (CARP). In general, NP-hard CARP is a special graph theory specifically arises from street services such as residential waste collection and road maintenance. By purpose, the design of the CARP model and its solution techniques is to find optimum (or near-optimum) routing cost for a fleet of vehicles involved in operation. In other words, finding minimum-cost routing is compulsory in order to reduce overall operation cost that related with vehicles. In this article, we provide a combination of various heuristics algorithm to solve a real case of CARP in waste collection and benchmark instances. These heuristics work as a central engine in finding initial solutions or near-optimum in search space without violating the pre-setting constraints. The results clearly show that these heuristics algorithms could provide good initial solutions in both real-life and benchmark instances.
Capacitated Vehicle Routing Problem Based on Improved Immune Genetic Algorithm%基于改进免疫算法的有能力约束车辆路径问题
Institute of Scientific and Technical Information of China (English)
梁勤欧
2011-01-01
针对遗传算法、免疫遗传算法在解决车辆路径问题(VRP)中存在的问题与不足,提出了一种改进免疫遗传算法.该算法主要在检查个体的多样性程度方面进行了简化,运用多样性指数阈值控制种群个体的多样性.通过有能力约束VRP的实验验证了新算法,得到了满意的效果.%There are some problems when genetic algorithm and immune genetic algorithm are used to solve Vehicle Routing Problem ( VRP). An improved immune genetic algorithm was proposed to overcome these disadvantages. The characteristic of the improved immune genetic algorithm is that the diversity detection method was simplified and population diversity was controlled by threshold determination method. Then a simple example of capacitated vehicle routing problem was conducted, and an improved immune genetic algorithm and perfect results were obtained.
Stochastic vehicle routing with recourse
DEFF Research Database (Denmark)
Gørtz, Inge Li; Nagarajan, Viswanath; Saket, Rishi
2012-01-01
We study the classic Vehicle Routing Problem in the setting of stochastic optimization with recourse. StochVRP is a two-stage problem, where demand is satisfied using two routes: fixed and recourse. The fixed route is computed using only a demand distribution. Then after observing the demand...... instantiations, a recourse route is computed - but costs here become more expensive by a factor λ. We present an O(log2n ·log(nλ))-approximation algorithm for this stochastic routing problem, under arbitrary distributions. The main idea in this result is relating StochVRP to a special case of submodular...
Implementing Vehicle Routing Algorithms
1975-09-01
Multiple Depot Vehicle Dispatch Problem," presented at the URSA/TIMS meeting San Juan, Puerto Rico, Oct. 1974. 28. Gillett, B., and Miller, L., " A Heuristic Algorithm for...45. Lam, T., "Comments on a Heuristic Algorithm for the Multiple Terminal Delivery Problem," Transportation Science, Vol. 4, No. 4, Nov. 1970, p. 403
Stochastic Vehicle Routing with Recourse
Goertz, Inge Li; Saket, Rishi
2012-01-01
We study the classic Vehicle Routing Problem in the setting of stochastic optimization with recourse. StochVRP is a two-stage optimization problem, where demand is satisfied using two routes: fixed and recourse. The fixed route is computed using only a demand distribution. Then after observing the demand instantiations, a recourse route is computed -- but costs here become more expensive by a factor lambda. We present an O(log^2 n log(n lambda))-approximation algorithm for this stochastic routing problem, under arbitrary distributions. The main idea in this result is relating StochVRP to a special case of submodular orienteering, called knapsack rank-function orienteering. We also give a better approximation ratio for knapsack rank-function orienteering than what follows from prior work. Finally, we provide a Unique Games Conjecture based omega(1) hardness of approximation for StochVRP, even on star-like metrics on which our algorithm achieves a logarithmic approximation.
Vehicle Routing with Uncertain Demand
R. Spliet (Remy)
2013-01-01
textabstractIn distribution networks a supplier transports goods from a distribution center to customers by means of vehicles with limited capacity. Drivers will drive routes on which they visit multiple customers to make deliveries. Typically, deliveries are made regularly and a fixed schedule is m
THE PERIODIC CAPACITATED ARC ROUTING PROBLEM LINEAR PROGRAMMING MODEL,METAHEURISTIC AND LOWER BOUNDS
Institute of Scientific and Technical Information of China (English)
Feng CHU; Nacima LABADI; Christian PRINS
2004-01-01
The Periodic Capacitated Arc Routing Problem (PCARP) generalizes the well known NP-hard Capacitated Arc Routing Problem (CARP) by extending the single period to multi-period horizon.The Capacitated Arc Routing Problem (CARP) is defined on an undirected network in which a fleet of identical vehicles is based at a depot node. A subset of edges, called tasks, must be serviced by a vehicle. The CARP consists of determining a set of feasible vehicle trips that minimizes the total cost of traversed edges. The PCARP involves the assignment of tasks to periods and the determination of vehicles trips in each period, to minimize the total cost on the whole horizon. This new problem arises in various real life applications such as waste collection, mail delivery, etc. In this paper, a new linear programming model and preliminary lower bounds based on graph transformation are proposed. A meta-heuristic approach - Scatter Search (SS) is developed for the PCARP and evaluated on a large variety of instances.
Partial Path Column Generation for the Vehicle Routing Problem
DEFF Research Database (Denmark)
Jepsen, Mads Kehlet; Petersen, Bjørn
This paper presents a column generation algorithm for the Capacitated Vehicle Routing Problem (CVRP) and the Vehicle Routing Problem with Time Windows (VRPTW). Traditionally, column generation models of the CVRP and VRPTW have consisted of a Set Partitioning master problem with each column repres...... of the giant tour’; a so-called partial path, i.e., not necessarily starting and ending in the depot. This way, the length of the partial path can be bounded and a better control of the size of the solution space for the pricing problem can be obtained....
A mathematical modeling proposal for a Multiple Tasks Periodic Capacitated Arc Routing Problem
Directory of Open Access Journals (Sweden)
Cleverson Gonçalves dos Santos
2015-12-01
Full Text Available The countless accidents and incidents occurred at dams at the last years, propelled the development of politics related with dams safety. One of the strategies is related to the plan for instrumentation and monitoring of dams. The monitoring demands from the technical team the reading of the auscultation data, in order to periodically monitor the dam. The monitoring plan of the dam can be modeled as a problem of mathematical program of the periodical capacitated arcs routing program (PCARP. The PCARP is considered as a generalization of the classic problem of routing in capacitated arcs (CARP due to two characteristics: 1 Planning period larger than a time unity, as that vehicle make several travels and; 2 frequency of associated visits to the arcs to be serviced over the planning horizon. For the dam's monitoring problem studied in this work, the frequent visits, along the time horizon, it is not associated to the arc, but to the instrument with which is intended to collect the data. Shows a new problem of Multiple tasks Periodic Capacitated Arc Routing Problem and its elaboration as an exact mathematical model. The new main characteristics presented are: multiple tasks to be performed on each edge or edges; different frequencies to accomplish each of the tasks; heterogeneous fleet; and flexibility for more than one vehicle passing through the same edge at the same day. The mathematical model was implemented and examples were generated randomly for the proposed model's validation.
Shortest Paths and Vehicle Routing
DEFF Research Database (Denmark)
Petersen, Bjørn
This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle R...... Routing Problem based on partial paths is presented. Finally, a practical application of finding shortest paths in the telecommunication industry is shown.......This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle...
Capacitated Vehicle Routing with Nonuniform Speeds
DEFF Research Database (Denmark)
Gørtz, Inge Li; Molinaro, Marco; Nagarajan, Viswanath;
2016-01-01
is the distance traveled divided by its speed.Our algorithm relies on a new approximate minimum spanning tree construction called Level-Prim, which is related to but different from Light Approximate Shortest-path Trees. We also extend the widely used tour-splitting technique to nonuniform speeds, using ideas from...... the 2-approximation algorithm for scheduling in unrelated machines....
Vehicle routing problem in investment fund allocation
Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah Rozita; Mohd, Ismail
2013-04-01
Since its introduction by Dantzig and Ramser in 1959, vehicle routing problem keeps evolving in theories, applications and variability. The evolution in computing and technology are also important contributors to research in solving vehicle routing problem. The main sectors of interests among researchers and practitioners for vehicle routing problem are transportation, distribution and logistics. However, literature found that concept and benefits of vehicle routing problem are not taken advantages of by researchers in the field of investment. Other methods found used in investment include multi-objective programming, linear programming, goal programming and integer programming. Yet the application of vehicle routing problem is not fully explored. A proposal on a framework of the fund allocation optimization using vehicle routing problem is presented here. Preliminary results using FTSE Bursa Malaysia data testing the framework are also given.
Vehicle Routing With User Generated Trajectory Data
DEFF Research Database (Denmark)
Ceikute, Vaida; Jensen, Christian S.
Rapidly increasing volumes of GPS data collected from vehicles provide new and increasingly comprehensive insight into the routes that drivers prefer. While routing services generally compute shortest or fastest routes, recent studies suggest that local drivers often prefer routes that are neithe...
A Generalized Assignment Heuristic for Vehicle Routing
1979-08-01
problem by ( VRP ). L. . . . .. i -3- Formulation of the Vehicle Routing Problem ( VRP ) min Z c X. (1)ijk 1) i jk S.t. Z aiYik < bk , k ,...,K (2) 1...Fisher and Ramchandran Jaikumar University of Pennsylvania August, 1979 ABSTR_2T We consider a common variant of the vehicle routing problem in which a...minimum size fleet that can feasibly service the specified demand. 1. Intrcduction Vehicle routing is a challenging logistics management
Vehicle Routing Optimization in Logistics Distribution Using Hybrid Ant Colony Algorithm
Directory of Open Access Journals (Sweden)
Chengming Qi
2013-09-01
Full Text Available The Vehicle Routing Problem (VRP is an important management problem in the field of physical distribution and logistics. Good vehicle routing can not only increase the profit of logistics but also make logistics management more scientific. The Capacitated Vehicle Routing Problem (CVRP constrained by the capacity of a vehicle is the extension of VRP. Our research applies a two-phase algorithm to address CVRP. It takes the advantages of Simulated Annealing (SA and ant colony optimization for solving the capacitated vehicle routing problem. In the first phase of proposed algorithm, simulated annealing provides a good initial solution for ant colony optimization. In the second phase, Iterative Local Search (ILS method is employed to seeking the close-to-optimal solution in local scope based on the capacity of the vehicle. Experimental results show that the proposed algorithm is superior to original ant colony optimization and simulated annealing separately reported on partial benchmark problems.
A variable neighborhood descent based heuristic to solve the capacitated location-routing problem
Directory of Open Access Journals (Sweden)
M. S. Jabal-Ameli
2011-01-01
Full Text Available Location-routing problem (LRP is established as a new research area in the context of location analysis. The primary concern of LRP is on locating facilities and routing of vehicles among established facilities and existing demand points. In this work, we address the capacitated LRP which arises in many practical applications within logistics and supply chain management. The objective is to minimize the overall system costs which include the fixed costs of opening depots and using vehicles at each depot site, and the variable costs associated with delivery activities. A novel heuristic is proposed which is based on variable neighborhood descent (VND algorithm to solve the resulted problem. The computational study indicates that the proposed VND based heuristic is highly competitive with the existing solution algorithms in terms of solution quality.
Classification of Dynamic Vehicle Routing Systems
DEFF Research Database (Denmark)
Larsen, Allan; Madsen, Oli B.G.; Solomon, Marius M.
2007-01-01
This chapter discusses important characteristics seen within dynamic vehicle routing problems. We discuss the differences between the traditional static vehicle routing problems and its dynamic counterparts. We give an in-depth introduction to the degree of dynamism measure which can be used...
Scheduling and routing Tactical Aerial Reconnaissance Vehicles
1990-01-01
Approved for public release; distribution unlimited. In this thesis we study the Marine Corps Tactical Aerial Reconnaissance Vehicle routing and scheduling problem. the present method of routing and scheduling is presented, along with possible implications for routing and scheduling when future expansion of vehicle assets becomes available. A review of current literature is given and comparisons are drawn between our problem and recent work. A model for the problem, which we call the Multi...
Disruption management of the vehicle routing problem with vehicle breakdown
DEFF Research Database (Denmark)
Mu, Q; Fu, Z; Lysgaard, Jens
2011-01-01
This paper introduces a new class of problem, the disrupted vehicle routing problem (VRP), which deals with the disruptions that occur at the execution stage of a VRP plan. The paper then focuses on one type of such problem, in which a vehicle breaks down during the delivery and a new routing sol...
Optimum Route Selection for Vehicle Navigation
Directory of Open Access Journals (Sweden)
Dalip
2016-02-01
Full Text Available The objective of Optimum Route Selection for Vehicle Navigation System (ORSVNS article is to develop a system, which provides information about real time alternate routes to the drivers and also helps in selecting the optimal route among all the alternate routes from an origin to destination. Two types of query systems, special and general, are designed for drivers. Here, the criterion for route selection is introduced using primary and secondary road attributes. The presented methodology helps the drivers in better decision making to choose optimal route using fuzzy logic. For experimental results ORSVNS is tested over 220 km portion of Haryana state in India.
Approximation algorithms for some vehicle routing problems
Bazgan, Cristina; Hassin, Refael; Monnot, Jérôme
2005-01-01
We study vehicle routing problems with constraints on the distance traveled by each vehicle or on the number of vehicles. The objective is either to minimize the total distance traveled by vehicles or to minimize the number of vehicles used. We design constant differential approximation algorithms for kVRP. Note that, using the differential bound for METRIC 3VRP, we obtain the randomized standard ratio . This is an improvement of the best-known bound of 2 given by Haimovich et al. (Vehicle Ro...
Rich Vehicle Routing Problems and Applications
DEFF Research Database (Denmark)
Wen, Min
the company’s solution in terms of all the objectives, including the travel time, customer waiting and daily workload balances, under the given constraints considered in the work. Finally, we address an integrated vehicle routing and driver scheduling problem, in which a large number of practical constraints......The Vehicle Routing Problem (VRP) is one of the most important and challenging optimization problems in the field of Operations Research. It was introduced by Dantzig and Ramser (1959) and defined as the problem of designing the optimal set of routes for a fleet of vehicles in order to serve...... given to various extensions of the VRP that arise in real life. These extensions are often called Rich Vehicle Routing Problems (RVRPs). In contrast to the research of classical VRP that focuses on the idealized models with unrealistic assumptions, the research of RVRPs considers those complicated...
Route selection for vehicle navigation and control
G. Pang; Chu, MH
2007-01-01
This paper presents an application of neural-fuzzy methodology for the problem of route selection in a typical vehicle navigation and control system. The idea of the primary attributes of a route is discussed, and a neural-fuzzy system is developed to help a user to select a route out of the many possible routes from an origin to the destination. The user may not adopt the recommendation provided by the system and choose an alternate route. One novel feature of the system is that the neural-f...
Implementation Weather-Type Models of Capacitated Arc Routing Problem via Heuristics
Directory of Open Access Journals (Sweden)
Zuhaimy Ismail
2011-01-01
Full Text Available Problem statement: In this study, we introduced a new and real-life condition of Capacitated Arc Routing Problem (CARP, a model that represents vehicles operation in waste collection. In general, we studied the element of rain drops that affected the collected waste weight in total by imposed a new variable namely rainy weight age. In rainy days, the household refusals did not increase in volumes, but in weights due to rain drops. Consequently, this matter thus burdened vehicles capacity and prolonged its operation time. This dynamic variable thus changes the initial CARP model where the existing model did not consider other external elements that have effected onto the model. Approach: Then we developed and enhanced CARP by integrating stochastic demand and time windows to suit the models with our specific case. Results: Objectively, CARP with stochastic demand (CARPSD and CARP with time windows (CARPTW were designed to minimize the total routing cost and number of trips for a vehicle. Our approach is to design CARP models in almost likely to road layout in residential area and graphically this model is called mesh network. We also developed a constructive heuristic that is called nearest procedure based on highest demand/cost (NPHDC and work in conjunction with switching rules to search the feasible solution. Conclusion: Our preliminary results show a higher cost and more trips are needed when the vehicle operates in rainy day compared to normal day operation.
Optimizing departure times in vehicle routes
Kok, A.L.; Hans, E.W.; Schutten, J.M.J.
2011-01-01
Most solution methods for the vehicle routing problem with time windows (VRPTW) develop routes from the earliest feasible departure time. In practice, however, temporary traffic congestion make such solutions non-optimal with respect to minimizing the total duty time. Furthermore, the VRPTW does not
Optimizing departure times in vehicle routes
Kok, A.L.; Hans, E.W.; Schutten, J.M.J.
2008-01-01
Most solution methods for the vehicle routing problem with time windows (VRPTW) develop routes from the earliest feasible departure time. However, in practice, temporal traffic congestions make that such solutions are not optimal with respect to minimizing the total duty time. Furthermore, VRPTW sol
Electric Vehicle Green Routing with Possible En-Route Recharging
BAOUCHE, Fouad; BILLOT, Romain; Trigui, Rochdi; EL FAOUZI, Nour Eddin
2014-01-01
The deployment of Electric Vehicles (EVs) is constrained mainly by the restricted autonomy, the lack of charging stations, the battery recharge time and recuperation capability (e.g. braking phases or downhill). In this study we aim to develop a green routing tool to encourage the use of EV. To overcome the autonomy limitation we propose a methodology for the EV that includes a charging stations location model, an energy graph construction for EV routing and a resolution scheme for the routin...
Combining Nearest Neighbor Search with Tabu Search for Large-Scale Vehicle Routing Problem
Du, Lingling; He, Ruhan
The vehicle routing problem is a classical problem in operations research, where the objective is to design least cost routes for a fleet of identical capacitated vehicles to service geographically scattered customers. In this paper, we present a new and effective hybrid metaheuristic algorithm for large-scale vehicle routing problem. The algorithm combines the strengths of the well-known Nearest Neighbor Search and Tabu Search into a two-stage procedure. More precisely, Nearest Neighbor Search is used to construct initial routes in the first stage and the Tabu Search is utilized to optimize the intra-route and the inter-route in the second stage. The presented algorithm is specifically designed for large-scale problems. The computational experiments were carried out on a standard benchmark and a real dataset with 6772 tobacco customers. The results demonstrate that the suggested method is highly competitive.
Genetic algorithms for the vehicle routing problem
Volna, Eva
2016-06-01
The Vehicle Routing Problem (VRP) is one of the most challenging combinatorial optimization tasks. This problem consists in designing the optimal set of routes for fleet of vehicles in order to serve a given set of customers. Evolutionary algorithms are general iterative algorithms for combinatorial optimization. These algorithms have been found to be very effective and robust in solving numerous problems from a wide range of application domains. This problem is known to be NP-hard; hence many heuristic procedures for its solution have been suggested. For such problems it is often desirable to obtain approximate solutions, so they can be found fast enough and are sufficiently accurate for the purpose. In this paper we have performed an experimental study that indicates the suitable use of genetic algorithms for the vehicle routing problem.
Particle Swarm Optimization with Genetic Operators for Vehicle Routing Problem
Directory of Open Access Journals (Sweden)
P. V. PURANIK
2012-07-01
Full Text Available Vehicle Routing Problem (VRP is to find shortest route thereby minimizing total cost. VRP is a NP-hard and Combinatorial optimization problem. Such problems increase exponentially with the problem size. Various derivative based optimization techniques are employed for optimization. Derivative based optimization techniques are difficult to evaluate. Therefore parallel search algorithm emerged to solve VRP. In this work, a particle swarm optimization (PSO algorithm and Genetic algorithm (GA with crossover and mutation operator are applied to two typical functions to deal with the problem of VRP efficiently using MATLAB software. Before solving VRP, optimization of functions using PSO and GA are checked. In this paper capacitate VRP with time window (CVRPTW is proposed. The computational result shows generation of input for VRP, optimization of Rastrigin function, Rosenbrock function using PSO and GA.
The Vehicle Routing Problem with Limited Vehicle Capacities
Directory of Open Access Journals (Sweden)
Fernando Taracena Sanz
2013-09-01
Full Text Available The vehicle routing problem (VRP has been an important research topic during the last decades because of his vital role in the productive systems efficiency. Most of the work done in this area has been directed to solve large scale problems which may not apply for small companies which are a very important engine of the world economy. This paper approaches the problem when limited vehicle resources are present and road transportation is used. This study assumes variable customer orders. Variable volume and weight vehicle capacities are considered and the proposed algorithm develops the vehicle delivery routes and the set of customer orders to deliver per vehicle minimizing a cost objective function. In sampling small company’s logistics costs, big cost savings are found when using the proposed method.
A Survey of Vehicle Routing Problem
Directory of Open Access Journals (Sweden)
Cao Wujun
2017-01-01
Full Text Available In recent years, vehicle routing problem (VRP has become an important content in logistics management research, and has been widely used in transportation system, logistics distribution system and express delivery system. In this paper, we discuss the classification of VRP, and summarize the common constraints of VRP, model algorithm and the main research results in recent years. Finally, we analyzes the future of VRP, and it is considered that the intelligent vehicle routing problem and intelligent heuristic algorithm will be an important field of future research.
Lower and upper bounds for the two-echelon capacitated location-routing problem
Contardo, Claudio; Hemmelmayr, Vera; Crainic, Teodor Gabriel
2012-01-01
In this paper, we introduce two algorithms to address the two-echelon capacitated location-routing problem (2E-CLRP). We introduce a branch-and-cut algorithm based on the solution of a new two-index vehicle-flow formulation, which is strengthened with several families of valid inequalities. We also propose an adaptive large-neighbourhood search (ALNS) meta-heuristic with the objective of finding good-quality solutions quickly. The computational results on a large set of instances from the literature show that the ALNS outperforms existing heuristics. Furthermore, the branch-and-cut method provides tight lower bounds and is able to solve small- and medium-size instances to optimality within reasonable computing times. PMID:24511176
Lower and upper bounds for the two-echelon capacitated location-routing problem.
Contardo, Claudio; Hemmelmayr, Vera; Crainic, Teodor Gabriel
2012-12-01
In this paper, we introduce two algorithms to address the two-echelon capacitated location-routing problem (2E-CLRP). We introduce a branch-and-cut algorithm based on the solution of a new two-index vehicle-flow formulation, which is strengthened with several families of valid inequalities. We also propose an adaptive large-neighbourhood search (ALNS) meta-heuristic with the objective of finding good-quality solutions quickly. The computational results on a large set of instances from the literature show that the ALNS outperforms existing heuristics. Furthermore, the branch-and-cut method provides tight lower bounds and is able to solve small- and medium-size instances to optimality within reasonable computing times.
A heuristic approach based on Clarke-Wright algorithm for open vehicle routing problem.
Pichpibul, Tantikorn; Kawtummachai, Ruengsak
2013-01-01
We propose a heuristic approach based on the Clarke-Wright algorithm (CW) to solve the open version of the well-known capacitated vehicle routing problem in which vehicles are not required to return to the depot after completing service. The proposed CW has been presented in four procedures composed of Clarke-Wright formula modification, open-route construction, two-phase selection, and route postimprovement. Computational results show that the proposed CW is competitive and outperforms classical CW in all directions. Moreover, the best known solution is also obtained in 97% of tested instances (60 out of 62).
Fast 3D route-planning approach for air vehicle
Tu, Jilin; Ding, Mingyue; Zhou, Chengping; Ai, Haojun
1997-06-01
A fast 3-D route planning method for unmanned air vehicle is proposed which can generate physically realizable 3-D route within a reasonable time. Our method includes two steps: First, 2-D route planning generates a route which satisfies turning radius constraint(abbreviated as R-constrained below); second, 3-D route planning generates 3-D route in vertical profile of the 2-D route. To make 2-D route R-constrained, a method is proposed by supposing 2-D route of air vehicle is composed of a sequence of arc route segments and tangential points between neighboring arcs are searching nodes. 3 -D route planning is considered as optimal control problem, and its route can be determined by applying motion equations of air vehicle. The experiments show that our method can produce feasible 3-D routes within a reasonable time, and ensure the planned 3-D routes satisfy aerodynamics constraints of air vehicle.
Overview of Stochastic Vehicle Routing Problems
Institute of Scientific and Technical Information of China (English)
郭耀煌; 谢秉磊; 郭强
2002-01-01
Stochastic vehicle routing problems (VRPs) play important roles in logistics, though they have not been studied systematically yet. The paper summaries the definition, properties and classification of stochastic VRPs, makes further discussion about two strategies in stochastic VRPs, and at last overviews dynamic and stochastic VRPs.
Analytical Analysis of Vehicle Routing and Inventory Routing Problems
2007-11-02
The objective of the project is to perform analytical analyses of heuristics for the Vehicle Routing Problem ( VRP ) and apply the results in models...asymptotic optimal solution value of the VRP with capacity and time window constraints and used it to develop a new and efficient algorithm. (2) Obtained a...characterization of the effectiveness of set partitioning formulations for VRPs . (3) Characterized the worst case behavior of the linear programming
Vehicle Coordinated Strategy for Vehicle Routing Problem with Fuzzy Demands
Directory of Open Access Journals (Sweden)
Chang-shi Liu
2016-01-01
Full Text Available The vehicle routing problem with fuzzy demands (VRPFD is considered. A fuzzy reasoning constrained program model is formulated for VRPFD, and a hybrid ant colony algorithm is proposed to minimize total travel distance. Specifically, the two-vehicle-paired loop coordinated strategy is presented to reduce the additional distance, unloading times, and waste capacity caused by the service failure due to the uncertain demands. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed approaches.
Vehicle Routing Algorithms for Local Delivery at Naval Supply Centers.
1981-03-01
the purpose of selecting a vehicle routing algorithm that can be automated. This investigation led the author to a survey of " vehicle routing problem " (also...the vehicle routing problem model is described and solution techniques are sur- veyed. Additionally, computational experience that operations...researchers have had with these solution techniques is pre- sented. There are several classical and theoretical problems related to the vehicle routing problem . These
Optimum Route Planning and Scheduling for Unmanned Aerial Vehicles
2008-12-01
Vehicle Routing Problem , VRP 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE...23 B. VEHICLE ROUTING PROBLEM ........................................................ 26 C. ORIENTEERING PROBLEM AND PRIZE...Team Orienteering Problem TSP Traveling Salesman Problem VRP Vehicle Routing Problem VRPPD VRP with Pick-Up And Delivering VRPTW VRP with Time
Directory of Open Access Journals (Sweden)
Masoud Rabbani
2016-02-01
Full Text Available This paper presents the capacitated Windy Rural Postman Problem with several vehicles. For this problem, two objectives are considered. One of them is the minimization of the total cost of all vehicle routes expressed by the sum of the total traversing cost and another one is reduction of the maximum cost of vehicle route in order to find a set of equitable tours for the vehicles. Mathematical formulation is provided. The multi-objective simulated annealing (MOSA algorithm has been modified for solving this bi-objective NP-hard problem. To increase algorithm performance, Taguchi technique is applied to design experiments for tuning parameters of the algorithm. Numerical experiments are proposed to show efficiency of the model. Finally, the results of the MOSA have been compared with MOCS (multi-objective Cuckoo Search algorithm to validate the performance of the proposed algorithm. The experimental results indicate that the proposed algorithm provides good solutions and performs significantly better than the MOCS.
Waste Collection Vehicle Routing Problem: Literature Review
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Hui Han
2015-08-01
Full Text Available Waste generation is an issue which has caused wide public concern in modern societies, not only for the quantitative rise of the amount of waste generated, but also for the increasing complexity of some products and components. Waste collection is a highly relevant activity in the reverse logistics system and how to collect waste in an efficient way is an area that needs to be improved. This paper analyzes the major contribution about Waste Collection Vehicle Routing Problem (WCVRP in literature. Based on a classification of waste collection (residential, commercial and industrial, firstly the key findings for these three types of waste collection are presented. Therefore, according to the model (Node Routing Problems and Arc Routing problems used to represent WCVRP, different methods and techniques are analyzed in this paper to solve WCVRP. This paper attempts to serve as a roadmap of research literature produced in the field of WCVRP.
Full truckload vehicle routing problem with profits
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Jian Li
2014-04-01
Full Text Available A new variant of the full truckload vehicle routing problem is studied. In this problem there are more than one delivery points corresponding to the same pickup point, and one order is allowed to be served several times by the same vehicle or different vehicles. For the orders which cannot be assigned because of resource constraint, the logistics company outsources them to other logistics companies at a certain cost. To maximize its profits, logistics company decides which to be transported by private fleet and which to be outsourced. The mathematical model is constructed for the problem. Since the problem is NP-hard and it is difficult to solve the large-scale problems with an exact algorithm, a hybrid genetic algorithm is proposed. Computational results show the effectiveness of the hybrid genetic algorithm.
The Balanced Billing Cycle Vehicle Routing Problem
Energy Technology Data Exchange (ETDEWEB)
Groer, Christopher S [ORNL; Golden, Bruce [University of Maryland; Edward, Wasil [American University
2009-01-01
Utility companies typically send their meter readers out each day of the billing cycle in order to determine each customer s usage for the period. Customer churn requires the utility company to periodically remove some customer locations from its meter-reading routes. On the other hand, the addition of new customers and locations requires the utility company to add newstops to the existing routes. A utility that does not adjust its meter-reading routes over time can find itself with inefficient routes and, subsequently, higher meter-reading costs. Furthermore, the utility can end up with certain billing days that require substantially larger meter-reading resources than others. However, remedying this problem is not as simple as it may initially seem. Certain regulatory and customer service considerations can prevent the utility from shifting a customer s billing day by more than a few days in either direction. Thus, the problem of reducing the meterreading costs and balancing the workload can become quite difficult. We describe this Balanced Billing Cycle Vehicle Routing Problem in more detail and develop an algorithm for providing solutions to a slightly simplified version of the problem. Our algorithm uses a combination of heuristics and integer programming via a three-stage algorithm. We discuss the performance of our procedure on a real-world data set.
A Cluster Based Scatter Search Heuristic for the Vehicle Routing Problem
Wendolsky, Rolf; Scheuerer, Stephan
2006-01-01
The Vehicle Routing Problem (VRP) is one of the most studied problems in the field of Operations Research. Closely related to the VRP is the Capacitated Clustering Problem (CCP). The VRP can be considered as an 'extension' of the CCP in the way that for each cluster in the CCP solution, additionally a route through all cluster customers and the depot has to be constructed to generate the routing information. In a previous study the Scatter Search methodology was used to solve the CCP. This al...
Flexible Bond Wire Capacitive Strain Sensor for Vehicle Tyres
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Siyang Cao
2016-06-01
Full Text Available The safety of the driving experience and manoeuvrability of a vehicle can be improved by detecting the strain in tyres. To measure strain accurately in rubber, the strain sensor needs to be flexible so that it does not deform the medium that it is measuring. In this work, a novel flexible bond wire capacitive strain sensor for measuring the strain in tyres is developed, fabricated and calibrated. An array of 25 micron diameter wire bonds in an approximately 8 mm × 8 mm area is built to create an interdigitated structure, which consists of 50 wire loops resulting in 49 capacitor pairs in parallel. Laser machining was used to pattern copper on a flexible printed circuit board PCB to make the bond pads for the wire attachment. The wire array was finally packaged and embedded in polydimethylsiloxane (PDMS, which acts as the structural material that is strained. The capacitance of the device is in a linear like relationship with respect to the strain, which can measure the strain up to at least ±60,000 micro-strain (±6% with a resolution of ~132 micro-strain (0.013%. In-tyre testing under static loading has shown the ability of the sensor to measure large tyre strains. The technology used for sensor fabrication lends itself to mass production and so the design is considered to be consistent with low cost commercialisable strain sensing technology.
Application of Harmony Search to Vehicle Routing
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Zong W. Geem
2005-01-01
Full Text Available A phenomenon-inspired meta-heuristic algorithm, harmony search, imitating music improvisation process, is introduced and applied to vehicle routing problem, then compared with one of the popular evolutionary algorithms, genetic algorithm. The harmony search algorithm conceptualized a group of musicians together trying to search for better state of harmony. This algorithm was applied to a test traffic network composed of one bus depot, one school and ten bus stops with demand by commuting students. This school bus routing example is a multi-objective problem to minimize both the number of operating buses and the total travel time of all buses while satisfying bus capacity and time window constraints. Harmony search could find good solution within the reasonable amount of time and computation.
Open Vehicle Routing Problem by Ant Colony Optimization
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Er. Gurpreet Singh
2014-01-01
Full Text Available Vehicle routing problem (VRP is real-world combinatorial optimization problem which determine the optimal route of a vehicle. Generally, toprovide the efficientvehicle serving to the customer through different services by visiting the number of cities or stops. The VRP follows the Travelling Salesman Problem (TSP, in which each of vehicle visiting a set of cities such that every city is visited by exactly one vehicle only once. This work proposes the Ant Colony Optimization (ACO-TSP algorithm to eliminate the tour loop for Open Vehicle routing Problem (OVRP. A key aspect of this algorithm is to plan the routes of buses that must pick up and deliver the school students from various bus stops on time, especially in the case of far distance covered by the vehicle in a rural area and find out the efficient and safe vehicle route.
A Branch-and-Price Algorithm for the Capacitated Arc Routing Problem with Stochastic Demands
DEFF Research Database (Denmark)
Christiansen, Christian Holk; Lysgaard, Jens; Wøhlk, Sanne
2009-01-01
We address the Capacitated Arc Routing Problem with Stochastic Demands (CARPSD), which we formulate as a Set Partitioning Problem. The CARPSD is solved by a Branch-and-Price algorithm, which we apply without graph transformation. The demand's stochastic nature is incorporated into the pricing...... problem. Computational results are reported....
A survey on multi trip vehicle routing problem
2008-01-01
The vehicle routing problem (VRP) and its variants are well known and greatly explored in the transportation literature. The vehicle routing problem can be considered as the scheduling of vehicles (trucks) to a set of customers under various side constraints. In most studies, a fundamental assumption is that a vehicle dispatched for service finishes its duty in that scheduling period after it returns back to the depot. Clearly, in many cases this assumption may not hold. Thus, in the last dec...
Genetic Algorithms for multiple objective vehicle routing
Geiger, Martin Josef
2008-01-01
The talk describes a general approach of a genetic algorithm for multiple objective optimization problems. A particular dominance relation between the individuals of the population is used to define a fitness operator, enabling the genetic algorithm to adress even problems with efficient, but convex-dominated alternatives. The algorithm is implemented in a multilingual computer program, solving vehicle routing problems with time windows under multiple objectives. The graphical user interface of the program shows the progress of the genetic algorithm and the main parameters of the approach can be easily modified. In addition to that, the program provides powerful decision support to the decision maker. The software has proved it's excellence at the finals of the European Academic Software Award EASA, held at the Keble college/ University of Oxford/ Great Britain.
The vehicle routing problem with backhauls
Energy Technology Data Exchange (ETDEWEB)
Goetschalckx, M.; Jacobs-Blecha, C.
1989-09-05
The Vehicle Routing Problem with Backhauls is a pickup/delivery problem where on each route all deliveries must be made before any pickups. A two-phased solution methodology is proposed. In the first phase, a high quality initial feasible solution is generated based on spacefilling curves. In the second phase, this solution is improved based on optimization of the subproblems identified in a mathematical model of the problem. An extensive computational analysis of several initial solution algorithms is presented, which identifies the tradeoffs between solution quality and computational requirements. The class of greedy algorithms is capacity oriented, while K-median algorithms focus on distance. It is concluded that the greedy and K-median algorithms generate equivalent tour lengths, but that the greedy procedure reduces the required number of trucks and increases the truck utilization. The effect of exchange improvement procedures as well as optimal procedures on solution quality and run time is demonstrated. Comparisons with the Clark-Wright method adapted to backhauls are also given. 4 figs., 26 refs.
Dynamic vehicle routing with time windows in theory and practice
Yang, Z.; Osta, van J.P.; Veen, van B.; Krevelen, van R.; Stam, A.; Kok, J.N.; Bäck, T.H.W.; Michael, Emmerich T. M.
2016-01-01
The vehicle routing problem is a classical combinatorial optimization problem. This work is about a variant of the vehicle routing problem with dynamically changing orders and time windows. In real-world applications often the demands change during operation time. New orders occur and others are can
Distributed Decision Making in Combined Vehicle Routing and Break Scheduling
Meyer, Christoph Manuel; Kopfer, Herbert; Kok, Adrianus Leendert; Schutten, Marco; Kreowski, Hans-Jörg; Scholz-Reiter, Bernd; Thoben, Klaus-Dieter
2011-01-01
The problem of combined vehicle routing and break scheduling comprises three subproblems: clustering of customer requests, routing of vehicles, and break scheduling. In practice, these subproblems are usually solved in the interaction between planners and drivers. We consider the case that the plann
Distributed Decision Making in Combined Vehicle Routing and Break Scheduling
Meyer, Christoph Manuel; Kopfer, Herbert; Kok, Adrianus Leendert; Schutten, Marco
2009-01-01
The problem of combined vehicle routing and break scheduling comprises three subproblems: clustering of customer requests, routing of vehicles, and break scheduling. In practice, these subproblems are usually solved in the interaction between planners and drivers. We consider the case that the plann
The vehicle routing problem with time windows and temporal dependencies
DEFF Research Database (Denmark)
Dohn, Anders Høeg; Rasmussen, Matias Sevel; Larsen, Jesper
2011-01-01
In this article, we formulate the vehicle routing problem with time windows and temporal dependencies. The problem is an extension of the well studied vehicle routing problem with time windows. In addition to the usual constraints, a scheduled time of one visit may restrain the scheduling options...
Dynamic Vehicle Routing for Robotic Networks (Workshop Briefing Charts)
2010-06-29
theoretic interpretation FB, EF, MP, KS, SLS (UCSB, MIT) Dynamic Vehicle Routing (Lecture 5/8) 29jun10 @ Baltimore, ACC 25 / 44 Partitioning with gossip ... Routing (Lecture 5/8) 29jun10 @ Baltimore, ACC 26 / 44 Gossip (asynchronous pair-wise) partitioning policy 1 Random communication between two regions 2...Dynamic Vehicle Routing for Robotic Networks Lecture #1: Introduction Francesco Bullo1 Emilio Frazzoli2 Marco Pavone2 Ketan Savla2 Stephen L. Smith2
Heuristic methods for a refuse collection vehicle routing problem
Energy Technology Data Exchange (ETDEWEB)
Mourao, M.C.; Almeida, M.T.
1994-12-31
The problem of generating the set of routes that minimizes the total time required to collect the household refuse in a particular quarter of Lisbon can be formulated as a Capacitated Arc Routing Problem with some side constraints. Our aim is to obtain approximate solutions, as the problem is known to be NP-hard. We present heuristic methods to generate feasible solutions and report their performance over a set of test problems.
Vehicle routing with multiple use of vehicles. Publication No. 95-19, and Publication No. 964
Energy Technology Data Exchange (ETDEWEB)
Taillard, E.D.; Gendreau, M.; Laporte, G.
1995-10-01
The vehicle routing problem is a central problem in distribution management. A variant of the standard problem with multiple use of vehicles involves the same vehicle being assigned to several routes during a given planning period. This paper develops a tabu search heuristic for this variant problem. The algorithm and computational results on a series of test problems are presented.
Congestion avoidance and break scheduling within vehicle routing
Kok, Adrianus Leendert
2010-01-01
Vehicle routing is a complex daily task for businesses such as logistic service providers and distribution firms. Planners have to assign many orders to many vehicles and, for each vehicle, assign a delivery sequence. The objective is to minimize total transport costs. These costs typically include
A Tabu Search Heuristic for the Vehicle Routing Problem
1994-01-01
The purpose of this paper is to describe TABUROUTE, a new tabu search heuristic for the vehicle routing problem with capacity and route length restrictions. The algorithm considers a sequence of adjacent solutions obtained by repeatedly removing a vertex from its current route and reinserting it into another route. This is done by means of a generalized insertion procedure previously developed by the authors. During the course of the algorithm, infeasible solutions are allowed. Numerical test...
Route Elimination Heuristic for Vehicle Routing Problem with Time Windows
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Sándor Csiszár
2005-11-01
Full Text Available The paper deals with the design of a route elimination (RE algorithm for thevehicle routing problem with time windows (VRPTW. The problem has two objectives, oneof them is the minimal number of routes the other is the minimal cost. To cope with theseobjectives effectively two-phase solutions are often suggested in the relevant literature. Inthe first phase the main focus is the route elimination, in the second one it is the costreduction. The algorithm described here is a part of a complete VRPWT study. The methodwas developed by studying the graph behaviour during the route elimination. For thispurpose a model -called “Magic Bricks” was developed. The computation results on theSolomon problem set show that the developed algorithm is competitive with the best ones.
Microcomputer-based vehicle routing and scheduling: An overview
Energy Technology Data Exchange (ETDEWEB)
Klein, A.J.
1987-08-01
Commercially available vehicle-routing and scheduling packages were surveyed to assess capabilities, categorize key characteristics, compare individual packages, and select candidate software for additional testing. Among the key characteristics addressed were backhauling, distance and vehicle travel-time calculation, geocoding, speed zones, natural barriers, time-window constraints, vehicle/stop matching constraints, and other constraints such as vehicle/driver operating costs. The survey included review of vendor literature, telephone interviews, site visits to review software, and the testing of demonstration packages on a set of sample distribution networks. Thirteen packages were reviewed; these were categorized by price and performance as follows; (1) inexpensive packages (costing $2000 or less), which solve the basic vehicle-routing problem but are somewhat limited in their ability to handle large numbers of vehicles and stops; (2) medium-priced systems (from $5000 to $20,000), which offer more capability to handle constraints such as multiple pickup and delivery, time windows, and multiple depots and provide manual intervention capability and enhanced graphics; (3) very expensive systems (from $50,000 to about $150,000), which can handle real-time situations in scheduling last-minute route changes and employ sophisticated graphics tools to change route schedules interactively. Out of the 13 packages, four demonstration vehicle-routing packages were obtained for testing of 4 sample networks; two of the packages were found to be capable of solving most vehicle-routing problem constraints for two versions of 21-city and 30-city networks.
The price of commitment in online stochastic vehicle routing
Energy Technology Data Exchange (ETDEWEB)
Bent, Russell W [Los Alamos National Laboratory; Van Hentenryck, Pascal [BROWN UNIV
2009-01-01
This paper considers online stochastic multiple vehicle routing with time windows in which requests arrive dynamically and the goal is to maximize the number of serviced customers. Early work has focused on very flexible routing settings where the decision to assign a vehicle to a customer is delayed until a vehicle is actually deployed to the customer. Motivated by real applications that require stability in the decision making, this paper considers a setting where the decision to assign a customer request to a vehicle must be taken when that request is accepted. Experimental results suggest that this constraint severely degrades the performance of existing algorithms. However, the paper shows how the use of stochastic information for vehicle assignment and request acceptance improves decision quality considerably. Moreover, the use of resource augmentation quantifies precisely the cost of commitment in online vehicle routing.
Multiple Charging Station Location-Routing Problem with Time Window of Electric Vehicle
Directory of Open Access Journals (Sweden)
Wang Li-ying
2015-11-01
Full Text Available This paper presents the electric vehicle (EV multiple charging station location-routing problem with time window to optimize the routing plan of capacitated EVs and the strategy of charging stations. In particular, the strategy of charging stations includes both infrastructure-type selection and station location decisions. The problem accounts for two critical constraints in logistic practice: the vehicle loading capacity and the customer time windows. A hybrid heuristic that incorporates an adaptive variable neighborhood search (AVNS with the tabu search algorithm for intensification was developed to address the problem. The specialized neighborhood structures and the selection methods of charging station used in the shaking step of AVNS were proposed. In contrast to the commercial solver CPLEX, experimental results on small-scale test instances demonstrate that the algorithm can find nearly optimal solutions on small-scale instances. The results on large-scale instances also show the effectiveness of the algorithm.
Cobweb heuristic for multi-objective vehicle routing problem
Joseph Okitonyumbe Y. F; Berthold Ulungu E.-L; Joel Kapiamba Nt.
2015-01-01
Solving a classical vehicle routing problem (VRP) by exact methods presents many difficulties for large dimension problem. Consequently, in multi-objective framework, heuristic or metaheuristic methods are required. Due to particular VRP structure, it seems that a dedicated heuristicis more suitable than a metaheuristic. The aim of this article is to collapse different heuristics solving classical VRP and adapt them for to solve the multi-objective vehicle routing problem (MOVRP). The so-call...
Cobweb Heuristic for solving Multi-Objective Vehicle Routing Problem
Okitonyumbe Y.F., Joseph; Ulungu, Berthold E.-L.; Kapiamba Nt., Joel
2015-01-01
Abstract Solving a classical vehicle routing problem (VRP) by exact methods presents many difficulties for large dimension problem. Consequently, in multi-objective framework, heuristic or metaheuristic methods are required. Due to particular VRP structure, it seems that a dedicated heuristic is more suitable than a metaheuristic. The aim of this article is to collapse different heuristics solving classical VRP and adapt them for to solve the multi-objective vehicle routing problem (MOVRP)...
Routing of Electric Vehicles: City Distribution in Copenhagen
DEFF Research Database (Denmark)
Linde, Esben; Larsen, Allan; Nørrelund, Anders Vedsted;
. The objective is to find the least cost plan for EV routing and compare this to conventional routing. A heuristic method is developed and tested on data based on real-life collected data on distribution vehicles in central Copenhagen, Denmark. The EVRPTW has so far received little attention in the literature...
Heuristic for vehicle routing problem with release and due dates
Johar, Farhana; Potts, Chris; Bennell, Julia
2014-06-01
This research is classifies as non-classical Vehicle Routing Problem (VRP) where the maximum release date of customer's demand of the route determine the vehicle departure time. Thus, there could be lateness on the delivery process from awaiting all customers' demand of the route to be released. A mathematical formulation is developed to represent the problem studied. Insertion method based on the cheapest cost is used to generate an initial solution. Then, Local Search technique is applied to improve the solution in term of minimization of total traveling and tardiness cost.
Optimizing investment fund allocation using vehicle routing problem framework
Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah Rozita
2014-07-01
The objective of investment is to maximize total returns or minimize total risks. To determine the optimum order of investment, vehicle routing problem method is used. The method which is widely used in the field of resource distribution shares almost similar characteristics with the problem of investment fund allocation. In this paper we describe and elucidate the concept of using vehicle routing problem framework in optimizing the allocation of investment fund. To better illustrate these similarities, sectorial data from FTSE Bursa Malaysia is used. Results show that different values of utility for risk-averse investors generate the same investment routes.
Multicriteria vehicle routing problem solved by artificial immune system
Directory of Open Access Journals (Sweden)
Bogna MRÓWCZYŃSKA
2015-09-01
Full Text Available Vehicles route planning in large transportation companies, where drivers are workers, usually takes place on the basis of experience or intuition of the employees. Because of the cost and environmental protection, it is important to save fuel, thus planning routes in an optimal way. In this article an example of the problem is presented solving delivery vans route planning taking into account the distance and travel time within the constraints of vehicle capacities, restrictions on working time of drivers and having varying degrees of movement. An artificial immune system was used for the calculations.
Visibility-constrained routing of unmanned aerial vehicles
Buck, Keith R.; Gassner, Richard R.; Poore, Aubrey B.; Yan, Xin
1999-07-01
Standard vehicle routing problems have been studied for decades in fields such as transportation, manufacturing, and commodity distribution. In this work, we proposed a variation of these problems that arise in routing Unmanned Aerial Vehicles (UAV's) in the presence of terrain obscuration. Specifically, the UAV must visit a location from which the object on the ground in mountainous regions can be viewed without actually flying over the object. Numerical results are presented for near optimal and real time algorithms which have been developed using Lagrangian relaxation techniques. Directions for future work that include priorities, time windows, and routing multiple UAV's with periodic and dynamic changes in the object locations are discussed.
Parallelization of the Vehicle Routing Problem with Time Windows
1999-01-01
This dissertation presents a number of algorithms for solving the Vehicle Routing Problem with Time Windows (VRPTW). The VRPTW is a generalization of the well known capacity constrained Vehicle Routing Problem (VRP). In the VRP a fleet of vehicles based at a central depot must service a set of customers. In the VRPTW each customer has a time window. Service of a customer must begin within the interval given by the time window. The objective is to minimize some aspect of operating costs (e.g. ...
The Vehicle Routing Problem with Time Windows and Temporal Dependencies
DEFF Research Database (Denmark)
Rasmussen, Matias Sevel; Dohn, Anders Høeg; Larsen, Jesper
assignment and routing problem with synchronization constraints. The problem has been solved by column generation. The synchronized vehicle dispatching problem (SVDP), which is a dynamic vehicle routing problem with synchronization between vehicles. Constraint programming and local search are applied...... to be scheduled with a certain slack between them. They refer to the vehicle problem as having interdependent time windows. Temporal dependencies have been modeled for a home care routing problem in a mixed integer programming model (MIP) which was solved with a standard MIP solver. An application with general...... temporal dependencies is also found in machine scheduling. Column generation is used to solve the problem. The pricing problem is primarily solved heuristically by local search and occasionally to optimality using a standard solver on an integer programming formulation of the pricing problem. Two compact...
A Study of Urgency Vehicle Routing Disruption Management Problem
Directory of Open Access Journals (Sweden)
Xuping Wang
2010-12-01
Full Text Available If a transit vehicle breaks down on a schedule trip, there are some vehicles in the system need to serve this trip and the former plan must be changed. For solving the urgency vehicle routing problem with disruption that may be vehicle breakdowns or traffic accidents in the logistics distribution system, through the analysis of the problem and the disruption measurement, the mathematics model is given based on the thought of disruption management. For the characteristics of the problem, a Lagrangian relaxation is given to simplify the model, and decompose the problem into two parts. The Lagrangian multiplier is given by subgradient method and the subproblems are solved by saving approach to gain the initial solution. A fast insertion algorithm is given to obtain a feasible solution for the primal problem. The results show that the algorithm designed in this paper performs very well for solving the urgency vehicle routing disruption management problem.
Optimization of Multiple Vehicle Routing Problems Using Approximation Algorithms
Directory of Open Access Journals (Sweden)
R. Nallusamy
2009-12-01
Full Text Available This paper deals with generating of an optimized route for multiple Vehicle routing Problems (mVRP. We used a methodology of clustering the given cities depending upon the number of vehicles and eachcluster is allotted to a vehicle. k- Means clustering algorithm has been used for easy clustering of the cities. In this way the mVRP has been converted into VRP which is simple in computation compared to mVRP. After clustering, an optimized route is generated for each vehicle in its allotted cluster. Once the clustering had been done and after the cities were allocated to the various vehicles, each cluster/tour was taken as an individual Vehicle Routing problem and the steps of Genetic Algorithm were applied to the cluster and iterated to obtain the most optimal value of the distance after convergence takes place. After the application of the variousheuristic techniques, it was found that the Genetic algorithm gave a better result and a more optimal tour for mVRPs in short computational time than other Algorithms due to the extensive search and constructive nature of the algorithm.
Optimization of Multiple Vehicle Routing Problems using Approximation Algorithms
Nallusamy, R; Dhanalaksmi, R; Parthiban, P
2010-01-01
This paper deals with generating of an optimized route for multiple Vehicle routing Problems (mVRP). We used a methodology of clustering the given cities depending upon the number of vehicles and each cluster is allotted to a vehicle. k- Means clustering algorithm has been used for easy clustering of the cities. In this way the mVRP has been converted into VRP which is simple in computation compared to mVRP. After clustering, an optimized route is generated for each vehicle in its allotted cluster. Once the clustering had been done and after the cities were allocated to the various vehicles, each cluster/tour was taken as an individual Vehicle Routing problem and the steps of Genetic Algorithm were applied to the cluster and iterated to obtain the most optimal value of the distance after convergence takes place. After the application of the various heuristic techniques, it was found that the Genetic algorithm gave a better result and a more optimal tour for mVRPs in short computational time than other Algorit...
Partially dynamic vehicle routing - models and algorithms
DEFF Research Database (Denmark)
Larsen, Allan; Madsen, Oli B.G.; Solomon, M.
2002-01-01
In this paper we propose a framework for dynamic routing systems based on their degree of dynamism. Next, we consider its impact on solution methodology and quality. Specifically, we introduce the Partially Dynamic Travelling Repairman Problem and describe several dynamic policies to minimize rou...
On the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Kallehauge, Brian
2006-01-01
by examining possible future lines of research in the area of the VRPTW. In the second paper ‘Lagrangian duality applied to the vehicle routing problem with time windows’ (Kallehauge, Larsen, and Madsen, Computers & Operations Research, 33:1464-1487, 2006) we consider the Lagrangian relaxation...... formulation is based on a formulation of the asymmetric traveling salesman problem with time windows and has the advantage of avoiding additional variables and linking constraints. In the new formulation of the VRPTW time windows aremodeled using path inequalities. The path inequalities eliminate time......The vehicle routing problem with time windows is concerned with the optimal routing of a fleet of vehicles between a depot and a number of customers that must be visited within a specified time interval, called a time window. The purpose of this thesis is to develop new and efficient solution...
A Sweep Coverage Scheme Based on Vehicle Routing Problem
Directory of Open Access Journals (Sweden)
Li Shu
2013-04-01
Full Text Available As an emerging coverage problem in wireless sensor networks, sweep coverage which introducing mobile sensors to cover points of interest within certain time interval can satisfy monitoring request in some particular application scenarios with less number of nodes than the conventional static coverage approach. In this work, aiming to support dynamical POI coverage and data delivery simultaneously, a novel sweep coverage scheme, named VRPSC(Vehicle Routing Problem based Sweep Coverage, is proposed by modeling the minimum number of required sensors problem in sweep coverage as a Vehicle Routing Problem (VRP. In VRPSC, an insertion algorithm is first introduced to create the initial scanning routes for POIs, and then the Simulated Annealing is employed to optimize these routes. The simulation results show that the VRPSC scheme achieves better performance than existing schemes.
A Subpath Ejection Method for the Vehicle Routing Problem
1998-01-01
Generically, ejection chains are methods conceived to allow solution transformations to be efficiently carried out by modifying a variable number of their components at each step of a local search algorithm. We consider a subpath ejection chain method for the vehicle routing problem (VRP) under capacity and route length restrictions. The method undertakes the identification of a substructure named the flower reference structure which, besides coordinating moves during an ejection chain constr...
Solving the Vehicle Routing Problem using Genetic Algorithm
Directory of Open Access Journals (Sweden)
Abdul Kadar Muhammad Masum
2011-08-01
Full Text Available The main goal of this research is to find a solution of Vehicle Routing Problem using genetic algorithms. The Vehicle Routing Problem (VRP is a complex combinatorial optimization problem that belongs to the NP-complete class. Due to the nature of the problem it is not possible to use exact methods for large instances of the VRP. Genetic algorithms provide a search technique used in computing to find true or approximate solution to optimization and search problems. However we used some heuristic in addition during crossover or mutation for tuning the system to obtain better result.
Parallelization of the Vehicle Routing Problem with Time Windows
DEFF Research Database (Denmark)
Larsen, Jesper
1999-01-01
of customers. In the VRPTW each customer has a time window. Service of a customer must begin within the interval given by the time window. The objective is to minimize some aspect of operating costs (e.g. total distance traveled, number of vehicles needed or a combination of parameters). Since the late 80's......This dissertation presents a number of algorithms for solving the Vehicle Routing Problem with Time Windows (VRPTW). The VRPTW is a generalization of the well known capacity constrained Vehicle Routing Problem (VRP). In the VRP a fleet of vehicles based at a central depot must service a set...... obtained using Lagrange relaxation. This dissertation is divided into three parts. First the theoretical framework is described. Thereafter a number of techniques to improve the performance of the column-generation framework are proposed and analyzed. Finally a parallel algorithm based on the sequential...
Electric Vehicle Routing Problems : models and solution approaches
Montoya, Jose-Alejandro
2016-01-01
Electric vehicles (evs) are one of the most promising technologies to reduce the greenhouse gas emissions. For this reason, the use of evs in service operations has dramatically increased in recent years. Despite their environmental benefits, evs still face technical constraints such as short autonomy and long charging times. Taking into account these constraints when planning ev operations leads to a new breed of vehicle routing problems (vrps), known as electricVrps (evrps). In addition, to...
Heuristics for Routing Heterogeneous Unmanned Vehicles with Fuel Constraints
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David Levy
2014-01-01
Full Text Available This paper addresses a multiple depot, multiple unmanned vehicle routing problem with fuel constraints. The objective of the problem is to find a tour for each vehicle such that all the specified targets are visited at least once by some vehicle, the tours satisfy the fuel constraints, and the total travel cost of the vehicles is a minimum. We consider a scenario where the vehicles are allowed to refuel by visiting any of the depots or fuel stations. This is a difficult optimization problem that involves partitioning the targets among the vehicles and finding a feasible tour for each vehicle. The focus of this paper is on developing fast variable neighborhood descent (VND and variable neighborhood search (VNS heuristics for finding good feasible solutions for large instances of the vehicle routing problem. Simulation results are presented to corroborate the performance of the proposed heuristics on a set of 23 large instances obtained from a standard library. These results show that the proposed VND heuristic, on an average, performed better than the proposed VNS heuristic for the tested instances.
A branch-and-cut algorithm for the vehicle routing problem with multiple use of vehicles
Directory of Open Access Journals (Sweden)
İsmail Karaoğlan
2015-06-01
Full Text Available This paper addresses the vehicle routing problem with multiple use of vehicles (VRPMUV, an important variant of the classic vehicle routing problem (VRP. Unlike the classical VRP, vehicles are allowed to use more than one route in the VRPMUV. We propose a branch-and-cut algorithm for solving the VRPMUV. The proposed algorithm includes several valid inequalities from the literature for the purpose of improving its lower bounds, and a heuristic algorithm based on simulated annealing and a mixed integer programming-based intensification procedure for obtaining the upper bounds. The algorithm is evaluated in terms of the test problems derived from the literature. The computational results which follow show that, if there were 120 customers on the route (in the simulation, the problem would be solved optimally in a reasonable amount of time.
A heuristic algorithm for a multi-product four-layer capacitated location-routing problem
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Mohsen Hamidi
2014-01-01
Full Text Available The purpose of this study is to solve a complex multi-product four-layer capacitated location-routing problem (LRP in which two specific constraints are taken into account: 1 plants have limited production capacity, and 2 central depots have limited capacity for storing and transshipping products. The LRP represents a multi-product four-layer distribution network that consists of plants, central depots, regional depots, and customers. A heuristic algorithm is developed to solve the four-layer LRP. The heuristic uses GRASP (Greedy Randomized Adaptive Search Procedure and two probabilistic tabu search strategies of intensification and diversification to tackle the problem. Results show that the heuristic solves the problem effectively.
Route-Based Control of Hybrid Electric Vehicles: Preprint
Energy Technology Data Exchange (ETDEWEB)
Gonder, J. D.
2008-01-01
Today's hybrid electric vehicle controls cannot always provide maximum fuel savings over all drive cycles. Route-based controls could improve HEV fuel efficiency by 2%-4% and help save nearly 6.5 million gallons of fuel annually.
Path inequalities for the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Kallehauge, Brian; Boland, Natashia; Madsen, Oli B.G.
2007-01-01
In this paper we introduce a new formulation of the vehicle routing problem with time windows (VRPTW) involving only binary variables. The new formulation is based on the formulation of the asymmetric traveling salesman problem with time windows by Ascheuer et al. (Networks 36 (2000) 69-79) and has...
Reachability cuts for the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Lysgaard, Jens
2004-01-01
This paper introduces a class of cuts, called reachability cuts, for the Vehicle Routing Problem with Time Windows (VRPTW). Reachability cuts are closely related to cuts derived from precedence constraints in the Asymmetric Traveling Salesman Problem with Time Windows and to k-path cuts...
Dynamic vehicle routing problems: Three decades and counting
DEFF Research Database (Denmark)
Psaraftis, Harilaos N.; Wen, Min; Kontovas, Christos A.
2016-01-01
Since the late 70s, much research activity has taken place on the class of dynamic vehicle routing problems (DVRP), with the time period after year 2000 witnessing a real explosion in related papers. Our paper sheds more light into work in this area over more than 3 decades by developing a taxonomy...
Genetic Algorithm for Vehicle Routing Problem with Backhauls
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W.Nurfahizul Ifwah. WA
2012-07-01
Full Text Available The Vehicle Routing Problem with Backhauls (VRPB is an extension of the classical Vehicle Routing Problem (VRP that includes both a set of customers to whom products are to be delivered and a set of suppliers whose goods need to be transported back to the distribution center. In addition, on each route all deliveries have to be made before any goods can be picked up to avoid rearranging the loads on the vehicle. The main objective for VRPB is to determine the network route to minimize the total cost, distance or time. There are a few methods that can be identified to solve this VRPB. The objective of this research is to present a heuristic method, called Genetic Algorithm (GA, for the VRPB. In brief, GA is a system developing methods that use the natural principle of a genetic population and involved three main processes that is crossover, mutation and inversion. GA implementation on the 68 nodes problems taken from Goetschalckx and Jacobs- Blecha is done by using Microsoft C++ Programming. Solutions to the problem are presented and performance comparison is conducted with the existing best solution. Several parameters in GA will be tested such as population size, crossover point and also the choice of operators used.
Dynamic vehicle routing with time windows in theory and practice.
Yang, Zhiwei; van Osta, Jan-Paul; van Veen, Barry; van Krevelen, Rick; van Klaveren, Richard; Stam, Andries; Kok, Joost; Bäck, Thomas; Emmerich, Michael
2017-01-01
The vehicle routing problem is a classical combinatorial optimization problem. This work is about a variant of the vehicle routing problem with dynamically changing orders and time windows. In real-world applications often the demands change during operation time. New orders occur and others are canceled. In this case new schedules need to be generated on-the-fly. Online optimization algorithms for dynamical vehicle routing address this problem but so far they do not consider time windows. Moreover, to match the scenarios found in real-world problems adaptations of benchmarks are required. In this paper, a practical problem is modeled based on the procedure of daily routing of a delivery company. New orders by customers are introduced dynamically during the working day and need to be integrated into the schedule. A multiple ant colony algorithm combined with powerful local search procedures is proposed to solve the dynamic vehicle routing problem with time windows. The performance is tested on a new benchmark based on simulations of a working day. The problems are taken from Solomon's benchmarks but a certain percentage of the orders are only revealed to the algorithm during operation time. Different versions of the MACS algorithm are tested and a high performing variant is identified. Finally, the algorithm is tested in situ: In a field study, the algorithm schedules a fleet of cars for a surveillance company. We compare the performance of the algorithm to that of the procedure used by the company and we summarize insights gained from the implementation of the real-world study. The results show that the multiple ant colony algorithm can get a much better solution on the academic benchmark problem and also can be integrated in a real-world environment.
ACTIVITY-BASED COSTING FOR VEHICLE ROUTING PROBLEMS
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A. J. Moolman
2012-01-01
Full Text Available
ENGLISH ABSTRACT:Activity-based costing (ABC is a costing model that identifies activity costs in an organisation. It assigns the cost of activity resources to generate the actual cost of products in order to eliminateunprofitable products and to lowerthe prices of overpriced ones. The vehicle routing problem (VRP is a combinatorial optimisation and nonlinear programming problem that seeks to service a number of customers with a fleet of vehicles in a cost-effective manner. In this article we propose a new approach to determine costing for vehicle routing type problems. The methodology incorporates the predictive sharing of a resource by clustering producers.
AFRIKAANSE OPSOMMING: ‘Activity-based costing’ (ABC is ’n kostemodel wat die aktiwiteitskoste in ’n organisasie identifiseer. Dit allokeer die koste van die bronne sodat die ware koste van die vervaardiging en dienste van die produk bereken kan word om winsgewendheid te bepaal. Die ‘vehicle routing problem’ (VRP is ’n kombinatoriese optimisering en nie-lineêre programmeringsprobleem wat verskeie kliënte met ’n vloot voertuie in die mees koste- effektiewe manier bedien. Die artikel bespreek ’n nuwe metode om die kombinasie van probleme op te los. Die metode maak gebruik van groeperingsalgoritmes om meer akkurate voertuig deling te voorspel.
Performansi Algoritma CODEQ dalam Penyelesaian Vehicle Routing Problem
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Annisa Kesy Garside
2014-01-01
Full Text Available Genetic Algorithm, Tabu Search, Simulated Annealing, and Ant Colony Optimization showed a good performance in solving vehicle routing problem. However, the generated solution of those algorithms was changeable regarding on the input parameter of each algorithm. CODEQ is a new, parameter free meta-heuristic algorithm that had been successfully used to solve constrained optimization problems, integer programming, and feed-forward neural network. The purpose of this research are improving CODEQ algorithm to solve vehicle routing problem and testing the performance of the improved algorithm. CODEQ algorithm is started with population initiation as initial solution, generated of mutant vector for each parent in every iteration, replacement of parent by mutant when fitness function value of mutant is better than parent’s, generated of new vector for each iteration based on opposition value or chaos principle, replacement of worst solution by new vector when fitness function value of new vector is better, iteration ceasing when stooping criterion is achieved, and sub-tour determination based on vehicle capacity constraint. The result showed that the average deviation of the best-known and the best-test value is 6.35%. Therefore, CODEQ algorithm is good in solving vehicle routing problem.
STUDI TENTANG TRAVELLING SALESMAN DAN VEHICLE ROUTING PROBLEM DENGAN TIME WINDOWS
I Nyoman Sutapa; I Gede Agus Widyadana; Christine Christine
2003-01-01
The article shows the study of model development of travelling salesman problem. Three models are studied, i.e. travelling salesman problem with time windows, vehicle routing problem, and vehicle routing problem with time windows. Abstract in Bahasa Indonesia : Dalam artikel ini dipaparkan kajian mengenai pengembangan model travelling salesman problem. Ada tiga model yang dikaji yaitu travelling salesman problem dengan time windows, vehicle routing problem, serta vehicle routing problem denga...
Solving the time dependent vehicle routing problem by metaheuristic algorithms
Johar, Farhana; Potts, Chris; Bennell, Julia
2015-02-01
The problem we consider in this study is Time Dependent Vehicle Routing Problem (TDVRP) which has been categorized as non-classical VRP. It is motivated by the fact that multinational companies are currently not only manufacturing the demanded products but also distributing them to the customer location. This implies an efficient synchronization of production and distribution activities. Hence, this study will look into the routing of vehicles which departs from the depot at varies time due to the variation in manufacturing process. We consider a single production line where demanded products are being process one at a time once orders have been received from the customers. It is assumed that order released from the production line will be loaded into scheduled vehicle which ready to be delivered. However, the delivery could only be done once all orders scheduled in the vehicle have been released from the production line. Therefore, there could be lateness on the delivery process from awaiting all customers' order of the route to be released. Our objective is to determine a schedule for vehicle routing that minimizes the solution cost including the travelling and tardiness cost. A mathematical formulation is developed to represent the problem and will be solved by two metaheuristics; Variable Neighborhood Search (VNS) and Tabu Search (TS). These algorithms will be coded in C ++ programming and run using 56's Solomon instances with some modification. The outcome of this experiment can be interpreted as the quality criteria of the different approximation methods. The comparison done shown that VNS gave the better results while consuming reasonable computational efforts.
Solving Vehicle Routing with Full Container Load and Time Windows
DEFF Research Database (Denmark)
Reinhardt, Line Blander; Spoorendonk, Simon; Pisinger, David
2012-01-01
A service provided by the liner shipping companies is the transport of containers by truck between the terminal and customers. These transports consist of import orders and export orders. Even though these transports concern containers and, therefore, each order is a full load, an import...... and an export order can be combined in one trip where the container is emptied at an import customer and taken to an export customer to be filled. Finding a set of optimal vehicle routes allowing these combinations is NP-hard. However, exploring the fact that the number of possible routes is small...
Dynamic Vehicle Routing for Robotic Networks: Models, Fundamental Limitations and Algorithms
2010-04-16
partitions. SIAM Review, January 2010. Submitted Francesco Bullo (UCSB) Dynamic Vehicle Routing 16apr10 @ ARL 31 / 34 Gossip partitioning policy: sample...Control Conference, Hollywood, CA, October 2009 Francesco Bullo (UCSB) Dynamic Vehicle Routing 16apr10 @ ARL 32 / 34 Gossip partitioning policy: analysis...Dynamic Vehicle Routing for Robotic Networks: Models, Fundamental Limitations and Algorithms Francesco Bullo Center for Control, Dynamical Systems
A Cost Assessment of the Dayton Public Schools Vehicle Routing Problem
2009-03-01
A COST ASSESMENT OF THE DAYTON PUBLIC SCHOOLS VEHICLE ROUTING PROBLEM THESIS...PUBLIC SCHOOLS VEHICLE ROUTING PROBLEM THESIS Presented to the Faculty Department of Operational Sciences Graduate School of... VEHICLE ROUTING PROBLEM Frankie L. Woods Jr., BS Captain, USAF Approved: ____________________________________ Dr
Dynamic vehicle routing problems: Three decades and counting
DEFF Research Database (Denmark)
Psaraftis, Harilaos N.; Wen, Min; Kontovas, Christos A.
2016-01-01
Since the late 70s, much research activity has taken place on the class of dynamic vehicle routing problems (DVRP), with the time period after year 2000 witnessing a real explosion in related papers. Our paper sheds more light into work in this area over more than 3 decades by developing a taxonomy...... of DVRP papers according to 11 criteria. These are (1) type of problem, (2) logistical context, (3) transportation mode, (4) objective function, (5) fleet size, (6) time constraints, (7) vehicle capacity constraints, (8) the ability to reject customers, (9) the nature of the dynamic element, (10...
Directory of Open Access Journals (Sweden)
Weizhen Rao
2016-01-01
Full Text Available The classical model of vehicle routing problem (VRP generally minimizes either the total vehicle travelling distance or the total number of dispatched vehicles. Due to the increased importance of environmental sustainability, one variant of VRPs that minimizes the total vehicle fuel consumption has gained much attention. The resulting fuel consumption VRP (FCVRP becomes increasingly important yet difficult. We present a mixed integer programming model for the FCVRP, and fuel consumption is measured through the degree of road gradient. Complexity analysis of FCVRP is presented through analogy with the capacitated VRP. To tackle the FCVRP’s computational intractability, we propose an efficient two-objective hybrid local search algorithm (TOHLS. TOHLS is based on a hybrid local search algorithm (HLS that is also used to solve FCVRP. Based on the Golden CVRP benchmarks, 60 FCVRP instances are generated and tested. Finally, the computational results show that the proposed TOHLS significantly outperforms the HLS.
Vehicle routing problem with time-varying speed
Institute of Scientific and Technical Information of China (English)
LIU Yun-zhong
2010-01-01
Vehicle routing problem with time-varying speed(VRPTS)is a generalization of vehicle routing problem in which the travel speed between two locations depends on the passing areas and the time of a day.This paper proposes a simple model for estimating time-varying travel speeds in VRPTS that relieves much bur den to the data-related problems.The study further presents three heuristics(saving technique,proximity priority searching technique,and insertion technique)for VRPTS,developed by extending and modifying the existing heuristics for conventional VRP.The results of computational experiments demonstrate that the proposed estimation model performs well and the saving technique is the best among the three heuristics.
Energy Technology Data Exchange (ETDEWEB)
Martins, P.; Gouveia, L.
1994-12-31
In this talk we discuss several linear integer programming formulations for a particular case of the Vehicle Routing Problem, where several classes of vehicles are considered and a fixed number of vehicles is imposed in each class. We also present a set of valid inequalities which lead to significant improvements on the lower bounds. Some heuristics are also discussed. We present computational results taken from a set of tests with the number of clients ranging from 13 to 75.
Routing and Allocation of Unmanned Aerial Vehicles with Communication Considerations
Sabo, Chelsea
Cooperative Unmanned Aerial Vehicles (UAV) teams are anticipated to provide much needed support for human intelligence, measurement and signature intelligence, signals intelligence, imagery intelligence, and open source intelligence through algorithms, software, and automation. Therefore, it is necessary to have autonomous algorithms that route multiple UAVs effectively and efficiently throughout missions and that these are realizable in the real-world given the associated uncertainties. Current routing strategies ignore communication constraints altogether. In reality, communication can be restricted by bandwidth, line-of-sight, maximum communication ranges, or a need for uninterrupted transmission. Generating autonomous algorithms that work effectively around these communication constraints is key for the future of UAV surveillance applications. In this work, both current and new routing strategies for UAVS are analyzed to determine how communications impact efficiency of information return. It is shown that under certain communication conditions, a new approach on routing can be more efficient than typically adopted strategies. This new approach defines and presents a new formulation based on a minimum delivery latency objective function. The problem is formulated such that information is not considered delivered until it is returned back to a high-bandwidth connection (depot) which is common when communication is restricted. The size of the region is shown to be dependent upon distance between requests, UAV bandwidth, UAV velocity, and data size, but it was shown that for large-sized data, long distances, and low bandwidth, it is generally better to route UAVs with this new minimum latency objective. With the added decision of when to deliver information to a high-bandwidth connection, an already computationally complex problem grows even faster. Because of scaling issues, a heuristic algorithm was developed that was constructed by analyzing the optimal
A Parallel Algorithm for the Vehicle Routing Problem
Energy Technology Data Exchange (ETDEWEB)
Groer, Christopher S [ORNL; Golden, Bruce [University of Maryland; Edward, Wasil [American University
2011-01-01
The vehicle routing problem (VRP) is a dicult and well-studied combinatorial optimization problem. We develop a parallel algorithm for the VRP that combines a heuristic local search improvement procedure with integer programming. We run our parallel algorithm with as many as 129 processors and are able to quickly nd high-quality solutions to standard benchmark problems. We assess the impact of parallelism by analyzing our procedure's performance under a number of dierent scenarios.
A green vehicle routing problem with customer satisfaction criteria
Afshar-Bakeshloo, M.; Mehrabi, A.; Safari, H.; Maleki, M.; Jolai, F.
2016-08-01
This paper develops an MILP model, named Satisfactory-Green Vehicle Routing Problem. It consists of routing a heterogeneous fleet of vehicles in order to serve a set of customers within predefined time windows. In this model in addition to the traditional objective of the VRP, both the pollution and customers' satisfaction have been taken into account. Meanwhile, the introduced model prepares an effective dashboard for decision-makers that determines appropriate routes, the best mixed fleet, speed and idle time of vehicles. Additionally, some new factors evaluate the greening of each decision based on three criteria. This model applies piecewise linear functions (PLFs) to linearize a nonlinear fuzzy interval for incorporating customers' satisfaction into other linear objectives. We have presented a mixed integer linear programming formulation for the S-GVRP. This model enriches managerial insights by providing trade-offs between customers' satisfaction, total costs and emission levels. Finally, we have provided a numerical study for showing the applicability of the model.
New exact algorithms for the vehicle routing problem
Energy Technology Data Exchange (ETDEWEB)
Mingozzi, A.; Galdacci, R.; Christofides, N.; Hadjiconstantinou, E.
1994-12-31
We consider the problem in which a fleet of M vehicles stationed at a central depot is to be optimally routed to supply customers with known demands subject to vehicle capacity constraints. This problem is referred as the Vehicle Routing Problem (VRP). In this paper we present two exact branch and bound algorithms for solving the VRP based on a Set Partitioning formulation of the problem. The first algorithm is based on a bounding procedure that finds a heuristic solution of the dual of the LP-relaxation of the Set Partitioning formulation without generating the entire set partitioning matrix. The dual solution obtained is then used to limit the set of the feasible routes containing the optimal VRP solution. The resulting Set Partitioning problem is solved by using a branch and bound method. The second algorithm is based on a lower bound that makes use of a new surrogate relaxation of the Set Partitioning problem. The two algorithms can solve both symmetric and asymmetric VRPS. Computational results are presented for a number of problems derived from the literature.
A Library of Local Search Heuristics for the Vehicle Routing Problem
Energy Technology Data Exchange (ETDEWEB)
Groer, Christopher S [ORNL; Golden, Bruce [University of Maryland; Edward, Wasil [American University
2010-01-01
The vehicle routing problem (VRP) is a difficult and well-studied combinatorial optimization problem. Real-world instances of the VRP can contain hundreds and even thousands of customer locations and can involve many complicating constraints, necessitating the use of heuristic methods. We present a software library of local search heuristics that allow one to quickly generate good solutions to VRP instances. The code has a logical, object-oriented design and uses efficient data structures to store and modify solutions. The core of the library is the implementation of seven local search operators that share a similar interface and are designed to be extended to handle additional options with minimal code change. The code is well-documented, is straightforward to compile, and is freely available for download at http://sites.google.com/site/vrphlibrary/ . The distribution of the code contains several applications that can be used to generate solutions to instances of the capacitated VRP.
Periodic Sweep Coverage Scheme Based on Periodic Vehicle Routing Problem
Directory of Open Access Journals (Sweden)
Li Shu
2014-03-01
Full Text Available We provide a sweep coverage algorithm for routing mobile sensors that communicate with a central data sink. This algorithm improves on its predecessors by reducing the number of unnecessary scans when different points of interest (POIs have different requirements for the time interval within which they must be scanned (sweep period. Most sweep coverage algorithms seek to minimize the number of sensors required to cover a given collection of POIs. When POIs have different sweep period requirements, existing algorithms will produce solutions in which sensors visit some POIs much more frequently than is necessary. We define this as the POI Over-Coverage problem. In order to address this problem we develop a Periodic Sweep Coverage (PSC scheme based on a well-known solution to the Periodic Vehicle Routing Problem (PVRP. Our algorithm seeks a route for the mobile sensors that minimizes the number of unnecessary visits to each POI. To verify and test the proposed scheme we implemented a C++ simulation and ran scenarios with a variety of POI topologies (number and distribution of the POIs and the speed at which sensors could travel. The simulation results show that the PSC algorithm outperforms other sweep coverage algorithms such as CSweep and Vehicle Routing Problem Sweep Coverage (VRPSC on both the average number of sensors in a solution and in the computational time required to find a solution. Our results also demonstrate that the PSC scheme is more suitable for the sweep coverage scenarios in which higher speed mobile sensors are used.
STUDI TENTANG TRAVELLING SALESMAN DAN VEHICLE ROUTING PROBLEM DENGAN TIME WINDOWS
Directory of Open Access Journals (Sweden)
I Nyoman Sutapa
2003-01-01
Full Text Available The article shows the study of model development of travelling salesman problem. Three models are studied, i.e. travelling salesman problem with time windows, vehicle routing problem, and vehicle routing problem with time windows. Abstract in Bahasa Indonesia : Dalam artikel ini dipaparkan kajian mengenai pengembangan model travelling salesman problem. Ada tiga model yang dikaji yaitu travelling salesman problem dengan time windows, vehicle routing problem, serta vehicle routing problem dengan time windows. Kata-kunci: travelling salesman problem, vehicle routing problem, time windows.
A Survey on Routing Mechanism and Techniques in Vehicle to Vehicle Communication (VANET
Directory of Open Access Journals (Sweden)
Yugal Kumar
2011-02-01
Full Text Available Now a day, one of the most attractive research topics in the area of Intelligent Traffic Control is Intervehiclecommunication. In V2V communication or we can also called VANET i.e. vehicular ad-hocnetwork; a vehicle can communicate to its neighboring vehicles even in the absence of a central BaseStation. The concept of this direct communication is to send vehicle safety messages one-to-one or oneto-many vehicles via wireless connection. Such messages are usually short in length and have very shortlifetime in which they must reach at the destination. The Inter-vehicle communication system is an adhocnetwork with high mobility and changing number of nodes, where mobile nodes dynamically createtemporary networks and transferring messages from one node to others by using multiple hops due tolimitation of short range. The routing in vehicular Ad hoc Networks (VANET has attracted manyattentions during the last few years. So in this paper we are focusing on the routing concept for theVANET i.e. principles for routing, decomposition of the routing function and requirement. The datadelivery through Vehicular Ad-hoc Networks is challenging since it must efficiently handle rapidtopology changes and a fragmented network.
Intelligent emission-sensitive routing for plugin hybrid electric vehicles.
Sun, Zhonghao; Zhou, Xingshe
2016-01-01
The existing transportation sector creates heavily environmental impacts and is a prime cause for the current climate change. The need to reduce emissions from this sector has stimulated efforts to speed up the application of electric vehicles (EVs). A subset of EVs, called plug-in hybrid electric vehicles (PHEVs), backup batteries with combustion engine, which makes PHEVs have a comparable driving range to conventional vehicles. However, this hybridization comes at a cost of higher emissions than all-electric vehicles. This paper studies the routing problem for PHEVs to minimize emissions. The existing shortest-path based algorithms cannot be applied to solving this problem, because of the several new challenges: (1) an optimal route may contain circles caused by detour for recharging; (2) emissions of PHEVs not only depend on the driving distance, but also depend on the terrain and the state of charge (SOC) of batteries; (3) batteries can harvest energy by regenerative braking, which makes some road segments have negative energy consumption. To address these challenges, this paper proposes a green navigation algorithm (GNA) which finds the optimal strategies: where to go and where to recharge. GNA discretizes the SOC, then makes the PHEV routing problem to satisfy the principle of optimality. Finally, GNA adopts dynamic programming to solve the problem. We evaluate GNA using synthetic maps generated by the delaunay triangulation. The results show that GNA can save more than 10 % energy and reduce 10 % emissions when compared to the shortest path algorithm. We also observe that PHEVs with the battery capacity of 10-15 KWh detour most and nearly no detour when larger than 30 KWh. This observation gives some insights when developing PHEVs.
Dynamic route guidance strategy in a two-route pedestrian-vehicle mixed traffic flow system
Liu, Mianfang; Xiong, Shengwu; Li, Bixiang
2016-05-01
With the rapid development of transportation, traffic questions have become the major issue for social, economic and environmental aspects. Especially, during serious emergencies, it is very important to alleviate road traffic congestion and improve the efficiency of evacuation to reduce casualties, and addressing these problems has been a major task for the agencies responsible in recent decades. Advanced road guidance strategies have been developed for homogeneous traffic flows, or to reduce traffic congestion and enhance the road capacity in a symmetric two-route scenario. However, feedback strategies have rarely been considered for pedestrian-vehicle mixed traffic flows with variable velocities and sizes in an asymmetric multi-route traffic system, which is a common phenomenon in many developing countries. In this study, we propose a weighted road occupancy feedback strategy (WROFS) for pedestrian-vehicle mixed traffic flows, which considers the system equilibrium to ease traffic congestion. In order to more realistic simulating the behavior of mixed traffic objects, the paper adopted a refined and dynamic cellular automaton model (RDPV_CA model) as the update mechanism for pedestrian-vehicle mixed traffic flow. Moreover, a bounded rational threshold control was introduced into the feedback strategy to avoid some negative effect of delayed information and reduce. Based on comparisons with the two previously proposed strategies, the simulation results obtained in a pedestrian-vehicle traffic flow scenario demonstrated that the proposed strategy with a bounded rational threshold was more effective and system equilibrium, system stability were reached.
Meta Heuristic Algorithms for Vehicle Routing Problem with Stochastic Demands
Directory of Open Access Journals (Sweden)
Geetha Shanmugam
2011-01-01
Full Text Available Problem statement: The shipment of goods from manufacturer to the consumer is a focal point of distribution logistics. In reality, the demand of consumers is not known a priori. This kind of distribution is dealt by Stochastic Vehicle Routing Problem (SVRP which is a NP-hard problem. In this proposed work, VRP with stochastic demand is considered. A probability distribution is considered as a random variable for stochastic demand of a customer. Approach: In this study, VRPSD is resolved using Meta heuristic algorithms such as Genetic Algorithm (GA, Particle Swarm Optimization (PSO and Hybrid PSO (HPSO. Dynamic Programming (DP is used to find the expected cost of each route generated by GA, PSO and HPSO. Results: The objective is to minimize the total expected cost of a priori route. The fitness value of a priori route is calculated using DP. In proposed HPSO, the initial particles are generated based Nearest Neighbor Heuristic (NNH. Elitism is used in HPSO for updating the particles. The algorithm is implemented using MATLAB7.0 and tested with problems having different number of customers. The results obtained are competitive in terms of execution time and memory usage. Conclusion: The computational time is reduced as polynomial time as O(nKQ time and the memory required is O(nQ. The ANOVA test is performed to compare the proposed HPSO with other heuristic algorithms.
SOLVING THE PROBLEM OF VEHICLE ROUTING BY EVOLUTIONARY ALGORITHM
Directory of Open Access Journals (Sweden)
Remigiusz Romuald Iwańkowicz
2016-03-01
Full Text Available In the presented work the vehicle routing problem is formulated, which concerns planning the collection of wastes by one garbage truck from a certain number of collection points. The garbage truck begins its route in the base point, collects the load in subsequent collection points, then drives the wastes to the disposal site (landfill or sorting plant and returns to the another visited collection points. The filled garbage truck each time goes to the disposal site. It returns to the base after driving wastes from all collection points. Optimization model is based on genetic algorithm where individual is the whole garbage collection plan. Permutation is proposed as the code of the individual.
A Capacitated Facility Location Approach for the Tanker Employment Problem
2005-03-01
Depot (MD) Vehicle Routing Problem (VRP) ......................................... 14 2.5 Capacitated Facility Location Problem (CFLP) with Sole...service receiver groups. In this sense the problem can be viewed as a multi-depot vehicle routing problem . Anchor points are two stationary points...for future research. 2.4 Multi-Depot (MD) Vehicle Routing Problem (VRP) Another approach to the Tanker Employment Problem is to model it as a VRP
Cooperative vehicle routing problem: an opportunity for cost saving
Zibaei, Sedighe; Hafezalkotob, Ashkan; Ghashami, Seyed Sajad
2016-02-01
In this paper, a novel methodology is proposed to solve a cooperative multi-depot vehicle routing problem. We establish a mathematical model for multi-owner VRP in which each owner (i.e. player) manages single or multiple depots. The basic idea consists of offering an option that owners cooperatively manage the VRP to save their costs. We present cooperative game theory techniques for cost saving allocations which are obtained from various coalitions of owners. The methodology is illustrated with a numerical example in which different coalitions of the players are evaluated along with the results of cooperation and cost saving allocation methods.
Robust Optimisation Approach for Vehicle Routing Problems with Uncertainty
Directory of Open Access Journals (Sweden)
Liang Sun
2015-01-01
Full Text Available We formulated a solution procedure for vehicle routing problems with uncertainty (VRPU for short with regard to future demand and transportation cost. Unlike E-SDROA (expectation semideviation robust optimisation approach for solving the proposed problem, the formulation focuses on robust optimisation considering situations possibly related to bidding and capital budgets. Besides, numerical experiments showed significant increments in the robustness of the solutions without much loss in solution quality. The differences and similarities of the robust optimisation model and existing robust optimisation approaches were also compared.
Dynamic Vehicle Routing for Data Gathering in Wireless Networks
Çelik, Güner D
2010-01-01
We consider a dynamic vehicle routing problem in wireless networks where messages arriving randomly in time and space are collected by a mobile receiver (vehicle or a collector). The collector is responsible for receiving these messages via wireless communication by dynamically adjusting its position in the network. Our goal is to utilize a combination of wireless transmission and controlled mobility to improve the delay performance in such networks. We show that the necessary and sufficient condition for the stability of such a system (in the bounded average number of messages sense) is given by {\\rho}<1 where {\\rho} is the average system load. We derive fundamental lower bounds for the delay in the system and develop policies that are stable for all loads {\\rho}<1 and that have asymptotically optimal delay scaling. Furthermore, we extend our analysis to the case of multiple collectors in the network. We show that the combination of mobility and wireless transmission results in a delay scaling of {\\The...
Optimal Routing for Heterogeneous Fixed Fleets of Multicompartment Vehicles
Directory of Open Access Journals (Sweden)
Qian Wang
2014-01-01
Full Text Available We present a metaheuristic called the reactive guided tabu search (RGTS to solve the heterogeneous fleet multicompartment vehicle routing problem (MCVRP, where a single vehicle is required for cotransporting multiple customer orders. MCVRP is commonly found in delivery of fashion apparel, petroleum distribution, food distribution, and waste collection. In searching the optimum solution of MCVRP, we need to handle a large amount of local optima in the solution spaces. To overcome this problem, we design three guiding mechanisms in which the search history is used to guide the search. The three mechanisms are experimentally demonstrated to be more efficient than the ones which only apply the known distance information. Armed with the guiding mechanisms and the well-known reactive mechanism, the RGTS can produce remarkable solutions in a reasonable computation time.
Design of a Capacitive Flexible Weighing Sensor for Vehicle WIM System
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Qing Li
2007-08-01
Full Text Available With the development of the Highway Transportation and Business Trade, vehicle weigh-in-motion (WIM technology has become a key technology and trend of measuring traffic loads. In this paper, a novel capacitive flexible weighing sensor which is light weight, smaller volume and easy to carry was applied in the vehicle WIM system. The dynamic behavior of the sensor is modeled using the Maxwell-Kelvin model because the materials of the sensor are rubbers which belong to viscoelasticity. A signal processing method based on the model is presented to overcome effects of rubber mechanical properties on the dynamic weight signal. The results showed that the measurement error is less than Ã���Â±10%. All the theoretic analysis and numerical results demonstrated that appliance of this system to weigh in motion is feasible and convenient for traffic inspection.
A Branch-and-Price Algorithm for Two Multi-Compartment Vehicle Routing Problems
DEFF Research Database (Denmark)
Mirzaei, Samira; Wøhlk, Sanne
2016-01-01
Despite the vast body of literature on vehicle routing problems, little attention has been paid to multi-compartment vehicle routing problems that investigate transportation of different commodities on the same vehicle, but in different compartments. In this project, we present two strategically...
The vehicle routing problem with time windows: State-of-the-art exact solution methods
DEFF Research Database (Denmark)
Desaulniers, Guy; Desrosiers, Jacques; Spoorendonk, Simon
2011-01-01
The vehicle routing problem with time windows (VRPTW) consists of finding least-cost vehicle routes to service given customers exactly once each while satisfying the vehicle capacity and customer time windows. The VRPTW has been widely studied. We present here a short survey on the successful exact...
The Linehaul-Feeder Vehicle Routing Problem with Virtual Depots and Time Windows
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Huey-Kuo Chen
2011-01-01
Full Text Available This paper addresses the linehaul-feeder vehicle routing problem with virtual depots and time windows (LFVRPTW. Small and large vehicles deliver services to customers within time constraints; small vehicles en route may reload commodities from either the physical depot or from the larger vehicle at a virtual depot before continuing onward. A two-stage solution heuristic involving Tabu search is proposed to solve this problem. The test results show that the LFVRPTW performs better than the vehicle routing problem with time windows in terms of both objective value and the number of small vehicles dispatched.
Analysis of the single-vehicle cyclic inventory routing problem
Aghezzaf, El-Houssaine; Zhong, Yiqing; Raa, Birger; Mateo, Manel
2012-11-01
The single-vehicle cyclic inventory routing problem (SV-CIRP) consists of a repetitive distribution of a product from a single depot to a selected subset of customers. For each customer, selected for replenishments, the supplier collects a corresponding fixed reward. The objective is to determine the subset of customers to replenish, the quantity of the product to be delivered to each and to design the vehicle route so that the resulting profit (difference between the total reward and the total logistical cost) is maximised while preventing stockouts at each of the selected customers. This problem appears often as a sub-problem in many logistical problems. In this article, the SV-CIRP is formulated as a mixed-integer program with a nonlinear objective function. After a thorough analysis of the structure of the problem and its features, an exact algorithm for its solution is proposed. This exact algorithm requires only solutions of linear mixed-integer programs. Values of a savings-based heuristic for this problem are compared to the optimal values obtained for a set of some test problems. In general, the gap may get as large as 25%, which justifies the effort to continue exploring and developing exact and approximation algorithms for the SV-CIRP.
Vehicle routing for the last mile of power system restoration
Energy Technology Data Exchange (ETDEWEB)
Bent, Russell W [Los Alamos National Laboratory; Coffrin, Carleton [Los Alamos National Laboratory; Van Hentenryck, Pascal [BROWN UNIV.
2010-11-23
This paper studied a novel problem in power system restoration: the Power Restoration Vehicle Routing Problem (PRVRP). The goal of PRVRPs is to decide how coordinate repair crews effectively in order to recover from blackouts as fast as possible after a disaster has occurred. PRVRPs are complex problems that combine vehicle routing and power restoration scheduling problems. The paper proposed a multi-stage optimization algorithm based on the idea of constraint injection that meets the aggressive runtime constraints necessary for disaster recovery. The algorithms were validated on benchmarks produced by the Los Alamos National Laboratory, using the infrastructure of the United States. The disaster scenarios were generated by state-of-the-art hurricane simulation tools similar to those used by the National Hurricane Center. Experimental results show that the constraint-injection algorithms can reduce the blackouts by 50% or more over field practices. Moreover, the results show that the constraint-injection algorithm using large neighborhood search over a blackbox simulator provide competitive quality and scales better than using a MIP solver on the subproblems.
Adaptive and Distributed Algorithms for Vehicle Routing in a Stochastic and Dynamic Environment
2010-11-18
underlying mathematical model is static and fits within the framework of the Vehicle Routing Problem (see [7] for a thorough introduction to the VRP...911–922, 2002. [7] P. Toth and D. Vigo, The vehicle routing problem . Philadelphia, PA: SIAM Monographs on Discrete Mathematics and Applications, 2002...in Applied Probability, vol. 25, pp. 947–978, 1993. [9] ——, “A stochastic and dynamic vehicle routing problem in the Eu- clidean plane,” Operations
An evolutionary algorithm for a real vehicle routing problem
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Adamidis, P.
2012-01-01
Full Text Available The NP-hard Vehicle Routing Problem (VRP is central in the optimisation of distribution networks. Its main objective is to determine a set of vehicle trips of minimum total cost. The ideal schedule will efficiently exploit the company's recourses, service all customers and satisfy the given (mainly daily constraints. There have been many attempts to solve this problem with conventional techniques but applied to small-scale simplified problems. This is due to the complexity of the problem and the large volume of data to be processed. Evolutionary Algorithms are search and optimization techniques that are capable of confronting that kind of problems and reach a good feasible solution in a reasonable period of time. In this paper we develop an Evolutionary Algorithm in order to solve the VRP of a specific transportation company in Volos, Greece with different vehicle capacities. The algorithm has been tested with different configurations and constraints, and proved to be effective in reaching a satisfying solution for the company's needs.
Driver's workload comparison in waste collection vehicle routing problem
Benjamin, Aida Mauziah; Abdul-Rahman, Syariza
2016-10-01
This paper compares the workload of the drivers for a waste collection benchmark problem. The problem involves ten data sets with different number of customers to be served and different number of disposal facilities available. Previous studies proposed a heuristic algorithm, namely Different Initial Customer (DIC) to solve the problem by constructing initial vehicles routes for the drivers with two main objectives; to minimize the total distance travelled and to minimize the total number of vehicles needed to collect the waste. The results from DIC compared well with other solutions in the literature. However, the balance of the workload among the vehicle drivers is not considered in the solutions. Thus in this paper, we evaluate the quality of the solutions in terms of the total number of customers served by each driver. Then the computational result is compared in terms of the total distance travelled which have been presented in a previous study. Comparison results show that the workload of the drivers are unbalance in terms of these two factors that may cause dissatisfaction among the drivers as well as to the managament.
A Comparison of Homogeneous and Heterogeneous Vehicle Fleet Size in Green Vehicle Routing Problem
Moutaoukil, Abdelhamid; Neubert, Gilles; Derrouiche, Ridha
2014-01-01
Part 1: Knowledge-Based Sustainability; International audience; To balance a fragmented logistics organization, Small and Medium Enterprises have to find collective solutions to decrease their environmental impact. Especially when the demand at each producer takes the form of small packages and low quantities this paper examines the effect of the introduction of a consolidation center on the environmental issue. Therefore, the Fleet Size and Mix Vehicle Routing Problem (FSMVRP) was adapted in...
Solving the vehicle routing problem by a hybrid meta-heuristic algorithm
Yousefikhoshbakht, Majid; Khorram, Esmaile
2012-01-01
The vehicle routing problem (VRP) is one of the most important combinational optimization problems that has nowadays received much attention because of its real application in industrial and service problems. The VRP involves routing a fleet of vehicles, each of them visiting a set of nodes such that every node is visited by exactly one vehicle only once. So, the objective is to minimize the total distance traveled by all the vehicles. This paper presents a hybrid two-phase algorithm called s...
Directory of Open Access Journals (Sweden)
Anan Mungwattana
2016-06-01
Full Text Available This paper deals with the vehicle routing problem with time windows (VRPTW. The VRPTW routes a set of vehicles to service customers having two-sided time windows, i.e. earliest and latest start of service times. The demand requests are served by capacitated vehicles with limited travel times to return to the depot. The purpose of this paper is to develop a hybrid algorithm that uses the modified push forward insertion heuristic (MPFIH, a λ-interchange local search descent method (λ-LSD and a genetic algorithm to solve the VRPTW with two objectives. The first objective aims to determine the minimum number of vehicles required and the second is to find the solution that minimizes the total travel time. A set of well-known benchmark problems are used to compare the quality of solutions. The results show that the proposed algorithm provides effective solutions compared with best found solutions and better than another heuristic used for comparison.
The dynamic multi-period vehicle routing problem
DEFF Research Database (Denmark)
Wen, Min; Cordeau, Jean-Francois; Laporte, Gilbert
2010-01-01
This paper considers the Dynamic Multi-Period Vehicle Routing Problem which deals with the distribution of orders from a depot to a set of customers over a multi-period time horizon. Customer orders and their feasible service periods are dynamically revealed over time. The objectives...... planning horizon. The multi-objective aspect of the problem is handled through a scalar technique approach. Computational results show that the proposed approach can yield high quality solutions within reasonable running times....... are to minimize total travel costs and customer waiting, and to balance the daily workload over the planning horizon. This problem originates from a large distributor operating in Sweden. It is modeled as a mixed integer linear program, and solved by means of a three-phase heuristic that works over a rolling...
Hybrid Ant Algorithm and Applications for Vehicle Routing Problem
Xiao, Zhang; Jiang-qing, Wang
Ant colony optimization (ACO) is a metaheuristic method that inspired by the behavior of real ant colonies. ACO has been successfully applied to several combinatorial optimization problems, but it has some short-comings like its slow computing speed and local-convergence. For solving Vehicle Routing Problem, we proposed Hybrid Ant Algorithm (HAA) in order to improve both the performance of the algorithm and the quality of solutions. The proposed algorithm took the advantages of Nearest Neighbor (NN) heuristic and ACO for solving VRP, it also expanded the scope of solution space and improves the global ability of the algorithm through importing mutation operation, combining 2-opt heuristics and adjusting the configuration of parameters dynamically. Computational results indicate that the hybrid ant algorithm can get optimal resolution of VRP effectively.
Assessment of the forest landscape along selected motor vehicle routes
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Janeczko Emilia
2016-03-01
Full Text Available This paper presents the results of research that aims to analyse and evaluate the attractiveness of the forest landscape in the vicinity of selected motor vehicle routes that differ in terms of technical parameters, such as motorways, regional roads and local (municipal roads. The diversity of landscape units was used as the measure of landscape attractiveness. Landscape diversity analysis allows to establish the details related to specific parts of the road and the options for configuring the road environment. These options relate to the way the forest is managed and mainly involve aspects of infrastructure and cultivation. They include activities such as afforestation work and rebuilding the species composition of forest stands. According to the research, the lower the technical class of a road, the greater is the need to take action to adapt the structural-tree stand system to meet the safety requirements of road users.
The Dynamic Multi-Period Vehicle Routing Problem
DEFF Research Database (Denmark)
Wen, Min; Cordeau, Jean-Francois; Laporte, Gilbert
This paper considers the Dynamic Multi-Period Vehicle Routing Problem which deals with the distribution of orders from a depot to a set of customers over a multi-period time horizon. Customer orders and their feasible service periods are dynamically revealed over time. The objectives...... are to minimize total travel costs and customer waiting, and to balance the daily workload over the planning horizon. This problem originates from a large distributor operating in Sweden. It is modeled as a mixed integer linear program, and solved by means of a three-phase heuristic that works over a rolling...... planning horizon. The multi-objective aspect of the problem is handled through a scalar technique approach. Computational results show that our solutions improve upon those of the Swedish distributor....
TSP based Evolutionary optimization approach for the Vehicle Routing Problem
Kouki, Zoulel; Chaar, Besma Fayech; Ksouri, Mekki
2009-03-01
Vehicle Routing and Flexible Job Shop Scheduling Problems (VRP and FJSSP) are two common hard combinatorial optimization problems that show many similarities in their conceptual level [2, 4]. It was proved for both problems that solving techniques like exact methods fail to provide good quality solutions in a reasonable amount of time when dealing with large scale instances [1, 5, 14]. In order to overcome this weakness, we decide in the favour of meta heuristics and we focalize on evolutionary algorithms that have been successfully used in scheduling problems [1, 5, 9]. In this paper we investigate the common properties of the VRP and the FJSSP in order to provide a new controlled evolutionary approach for the CVRP optimization inspired by the FJSSP evolutionary optimization algorithms introduced in [10].
DEFF Research Database (Denmark)
Larsen, Jesper
2002-01-01
Two ideas for using structural information for solving the Vehicle Routing Problem with Time Windows (VRPTW) is presented. The VRPTW is a generalization of the well known capacity constrained Vehicle Routing Problem (VRP). Both techniques are based on solving the VRPTW using a Branch...
Kok, A. Leendert; Meyer, C. Manuel; Kopfer, Herbert; Schutten, J. Marco J.
2009-01-01
In practice, apart from the problem of vehicle routing, schedulers also face the problem of nding feasible driver schedules complying with complex restrictions on drivers' driving and working hours. To address this complex interdependent problem of vehicle routing and break scheduling, we propose a
Kok, A. Leendert; Meyer, C. Manuel; Kopfer, Herbert; Schutten, J. Marco J.
2009-01-01
In practice, apart from the problem of vehicle routing, schedulers also face the problem of finding feasible driver schedules complying with complex restrictions on drivers' driving and working hours. To address this complex interdependent problem of vehicle routing and break scheduling, we propose
Design of Vehicle Routing by Integrating Optimization and Simulated Annealing Approach
Institute of Scientific and Technical Information of China (English)
Chwen-Tzeng; Su; Chikong; Hwang
2002-01-01
The vehicle routing problem (VRP) can be described as the problem of designing the optimal delivery or collection routes from one or several depots to a number of geographically scattered customers, subject to load constraints. The routing decision involves determining which of the demand s will be satisfied by each vehicle and what route each vehicle will follow in s erving its assigned demand in order to minimize total delivery cost. In this pap er, a methodology for the design of VRP by integrating...
A Hybrid TCNN Optimization Approach for the Capacity Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
A novel approximation algorithm was proposed for the problem of finding the minimum total cost of all routes in Capacity Vehicle Routing Problem (CVRP). CVRP can be partitioned into three parts: the selection of vehicles among the available vehicles, the initial routing of the selected fleet and the routing optimization. Fuzzy Cmeans (FCM) can group the customers with close Euclidean distance into the same vehicle according to the principle of similar feature partition. Transiently chaotic neural network (TCNN) combines local search and global search, possessing high search efficiency. It will solve the routes to near optimality. A simple tabu search (TS)procedure can improve the routes to more optimality. The computations on benchmark problems and comparisons with other results in literatures show that the proposed algorithm is a viable and effective approach for CVRP.
Refinements of the column generation process for the Vehicle Routing Problem with Time Windows
DEFF Research Database (Denmark)
Larsen, Jesper
2004-01-01
The Vehicle Routing Problem with Time Windows is a generalization of the well known capacity constrained Vehicle Routing Problem. A homogeneous fleet of vehicles has to service a set of the customers and fulfill their demands. The service of the customers can only start within a well-defined time......-and-Bound, also known as Branch-and-Price. This paper presents two ideas for run-time improvements of the Branch-and-Price framework for the Vehicle Routing Problem with Time Windows. Both ideas reveal a significant potential for using run-time refinements when speeding up an exact approach without compromising...
MULTI-VEHICLE COVERING TOUR PROBLEM: BUILDING ROUTES FOR URBAN PATROLLING
Washington Alves Oliveira; Antonio Carlos Moretti; Ednei Felix Reis
2015-01-01
ABSTRACT In this paper we study a particular aspect of the urban community policing: routine patrol route planning. We seek routes that guarantee visibility, as this has a sizable impact on the community perceived safety, allowing quick emergency responses and providing surveillance of selected sites (e.g., hospitals, schools). The planning is restricted to the availability of vehicles and strives to achieve balanced routes. We study an adaptation of the model for the multi-vehicle covering t...
A hybrid GA-TS algorithm for open vehicle routing optimization of coal mines material
Energy Technology Data Exchange (ETDEWEB)
Yu, S.W.; Ding, C.; Zhu, K.J. [China University of Geoscience, Wuhan (China)
2011-08-15
In the open vehicle routing problem (OVRP), the objective is to minimize the number of vehicles and the total distance (or time) traveled. This study primarily focuses on solving an open vehicle routing problem (OVRP) by applying a novel hybrid genetic algorithm and the Tabu search (GA-TS), which combines the GA's parallel computing and global optimization with TS's Tabu search skill and fast local search. Firstly, the proposed algorithm uses natural number coding according to the customer demands and the captivity of the vehicle for globe optimization. Secondly, individuals of population do TS local search with a certain degree of probability, namely, do the local routing optimization of all customer sites belong to one vehicle. The mechanism not only improves the ability of global optimization, but also ensures the speed of operation. The algorithm was used in Zhengzhou Coal Mine and Power Supply Co., Ltd.'s transport vehicle routing optimization.
Davis, L C
2016-01-01
Up-to-date information wirelessly communicated among vehicles can be used to select the optimal route between a given origin and destination. To elucidate how to make use of such information, simulations are performed for autonomous vehicles traveling on a square lattice of roads. All the possible routes between the origin and the destination (without backtracking) are of the same length. Congestion is the only determinant of delay. At each intersection, right-of-way is given to the closest vehicle. There are no traffic lights. Trip times of a subject vehicle are recorded for various initial conditions using different routing algorithms. Surprisingly, the simplest algorithm, which is based on the total number of vehicles on a route, is as good as one based on computing travel times from the average velocity of vehicles on each road segment.
A heterogeneous fleet vehicle routing model for solving the LPG distribution problem: A case study
Onut, S.; Kamber, M. R.; Altay, G.
2014-03-01
Vehicle Routing Problem (VRP) is an important management problem in the field of distribution and logistics. In VRPs, routes from a distribution point to geographically distributed points are designed with minimum cost and considering customer demands. All points should be visited only once and by one vehicle in one route. Total demand in one route should not exceed the capacity of the vehicle that assigned to that route. VRPs are varied due to real life constraints related to vehicle types, number of depots, transportation conditions and time periods, etc. Heterogeneous fleet vehicle routing problem is a kind of VRP that vehicles have different capacity and costs. There are two types of vehicles in our problem. In this study, it is used the real world data and obtained from a company that operates in LPG sector in Turkey. An optimization model is established for planning daily routes and assigned vehicles. The model is solved by GAMS and optimal solution is found in a reasonable time.
Directory of Open Access Journals (Sweden)
Alireza Goli
2015-09-01
Full Text Available Distribution and optimum allocation of emergency resources are the most important tasks, which need to be accomplished during crisis. When a natural disaster such as earthquake, flood, etc. takes place, it is necessary to deliver rescue efforts as quickly as possible. Therefore, it is important to find optimum location and distribution of emergency relief resources. When a natural disaster occurs, it is not possible to reach some damaged areas. In this paper, location and multi-depot vehicle routing for emergency vehicles using tour coverage and random sampling is investigated. In this study, there is no need to visit all the places and some demand points receive their needs from the nearest possible location. The proposed study is implemented for some randomly generated numbers in different sizes. The preliminary results indicate that the proposed method was capable of reaching desirable solutions in reasonable amount of time.
The Electric Fleet Size and Mix Vehicle Routing Problem with Time Windows and Recharging Stations
DEFF Research Database (Denmark)
Hiermann, Gerhard; Puchinger, Jakob; Røpke, Stefan
2016-01-01
Due to new regulations and further technological progress in the field of electric vehicles, the research community faces the new challenge of incorporating the electric energy based restrictions into vehicle routing problems. One of these restrictions is the limited battery capacity which makes...... detours to recharging stations necessary, thus requiring efficient tour planning mechanisms in order to sustain the competitiveness of electric vehicles compared to conventional vehicles. We introduce the Electric Fleet Size and Mix Vehicle Routing Problem with Time Windows and Recharging Stations (E...
Goal-programming model of the stochastic vehicle-routing problem
Energy Technology Data Exchange (ETDEWEB)
Zare-Mehrjerdi, Y.
1986-01-01
This research proposes a Goal Programming (GP) model of the Stochastic Vehicle Routing Problem (SVRP). The SVRP examined considers the multiple-vehicle, single-depot-node routing problem in which customer demand and travel and unload times are random variables having known distribution functions. The problem formulation of the SVRP is divided into two major stages which are referred to as Route Construction Stage (RCS) and Route Improvement Stage (RIS). The RCS of the SVRP is required in order to partition a set of stations into feasible sets of routes, one for each vehicle, using an appropriate heuristic approach. The RIS of the problem is required in order to sequence the stations on each vehicle route to meet the customer's and decision maker's requirements by applying a GP method. Two problems discuss the GP formulation of the RIS, which is used for improving the arrangement of stations on each vehicle route based on the customer's and decision maker's criteria. The formulation of the RCS of the problem is divided into two sections according to the type of criteria that is to be minimized. A substantial improvement in the results of the SVRP can be obtained by integrating the customer's and decision maker's requirements with the SVRP in order to determine the final arrangement of stations for each vehicle route.
REFINEMENTS OF THE COLUMN GENERATION PROCESS FOR THE VEHICLE ROUTING PROBLEM WITH TIME WINDOWS
Institute of Scientific and Technical Information of China (English)
Jesper LARSEN
2004-01-01
The Vehicle Routing Problem with Time Windows is a generalization of the well known capacity constrained Vehicle Routing Problem. A homogeneous fleet of vehicles has to service a set of customers. The service of the customers can only start within a well-defined time interval denoted the time window. The objective is to determine routes for the vehicles that minimizes the accumulated cost (or distance). Currently the best approaches for determining optimal solutions are based on column generation and Branch-and-Bound, also known as Branch-and-Price. This paper presents two ideas for run-time improvements of the Branch-and-Price framework for the Vehicle Routing Problem with Time Windows. Both ideas reveal a significant potential for run-time refinements when speeding up an exact approach without compromising optimality.
Adaptive search techniques for problems in vehicle routing, part II: A numerical comparison
Directory of Open Access Journals (Sweden)
Kritzinger Stefanie
2015-01-01
Full Text Available Research in the field of vehicle routing often focused on finding new ideas and concepts in the development of fast and efficient algorithms for an improved solution process. Early studies introduce static tailor-made strategies, but trends show that algorithms with generic adaptive policies - which emerged in the past years - are more efficient to solve complex vehicle routing problems. In this first part of the survey, we present an overview of recent literature dealing with adaptive or guided search techniques for problems in vehicle routing.
Adaptive search techniques for problems in vehicle routing, part I: A survey
Directory of Open Access Journals (Sweden)
Kritzinger Stefanie
2015-01-01
Full Text Available Research in the field of vehicle routing often focused on finding new ideas and concepts in the development of fast and efficient algorithms for an improved solution process. Early studies introduce static tailor-made strategies, but trends show that algorithms with generic adaptive policies - which emerged in the past years - are more efficient to solve complex vehicle routing problems. In this first part of the survey, we present an overview of recent literature dealing with adaptive or guided search techniques for problems in vehicle routing.
Directory of Open Access Journals (Sweden)
Reshani P. Liyanage
2016-08-01
Full Text Available This paper is focused on the growing need of integrating environmentally sound choices into supply-chain management. The concept of green economic practices driven by the environmental sustainability challenges posed the concept of green logistics, to evolve in the last few decades.To establish the field further, the purpose of this paper is twofold. First, it offers anextensive systematic review of literature on GL with a critical review of the studies that have been considered in the paper.Second, it offers a conceptual analytical model where the canonical capacitated vehicle routing problem is extended to add the measures of Carbon Dioxide (CO2 emissions. The proposed, multi objective optimization model tackles the conflicting objectives of CO2 emission reduction and cost minimization. The developed generic model integrates the traffic information in providing the user with opportunity to have more realistic solution. The model also enables strategic decision making to improve the GL operations while allowing greatercompetitive advantage
2016-01-01
The multi Vehicle Routing Problem with Pickup and Delivery with Time Windows is a challenging version of the Vehicle Routing Problem. In this paper, by embedding many complex assignment routing constraints through constructing a multi dimensional network, we intend to reach optimality for local clusters derived from a reasonably large set of passengers on real world transportation networks. More specifically, we introduce a multi vehicle state space time network representation in which only t...
An Adaptable Variable Neighborhood Search for the Vehicle Routing Problem with Order Outsourcing
2014-01-01
In practice, many package transportation companies lower their costs by hiring outside carriers to serve orders that cannot be served efficiently by their own trucks. The problem which takes the order outsource option into account is the Vehicle Routing Problem with Private Fleet and Common Carrier. In this variant of the Vehicle Routing Problem, orders are either delivered by an outside carrier, the common carrier, which receives an order specific price for this or by the own fleet, the priv...
The relationship between vehicle routing and scheduling and green logistics - a literature survey
Sbihi, A.; Eglese, R W
2007-01-01
The basic Vehicle Routing and Scheduling Problem (VRSP) is described followed by an outline of solution approaches. Different variations of the basic VRSP are examined that involve the consideration of additional constraints or other changes in the structure of the appropriate model. An introduction is provided to Green Logistics issues that are relevant to vehicle routing and scheduling including discussion of the environmental objectives that should be considered. Particular consideration i...
The Relationship between Vehicle Routing & Scheduling and Green Logistics - A Literature Survey
Sbihi, Abdelkader; W. Eglese, Richard
2007-01-01
The basic Vehicle Routing and Scheduling Problem (VRSP) is described followed by an outline of solution approaches. Different variations of the basic VRSP are examined that involve the consideration of additional constraints or other changes in the structure of the appropriate model. An introduction is provided to Green Logistics issues that are relevant to vehicle routing and scheduling including discussion of the environmental objectives that should be considered. Particular consideration i...
The waste collection vehicle routing problem with time windows in a city logistics context
DEFF Research Database (Denmark)
Buhrkal, Katja Frederik; Larsen, Allan; Røpke, Stefan
2012-01-01
Collection of waste is an important logistic activity within any city. In this paper we study how to collect waste in an efficient way. We study the Waste Collection Vehicle Routing Problem with Time Window which is concerned with finding cost optimal routes for garbage trucks such that all garbage...
A savings based method for real-life vehicle routing problems
A. Poot; G. Kant; A.P.M. Wagelmans (Albert)
1999-01-01
textabstractThis paper describes a Savings Based algorithm for the Extended Vehicle Routing Problem. This algorithm is compared with a Sequential Insertion algorithm on real-life data. Besides the traditional quality measures such as total distance traveled and total workload, we compare the routing
The Vehicle Rescheduling Problem
R. Spliet (Remy); A.F. Gabor (Adriana); R. Dekker (Rommert)
2009-01-01
textabstractThe capacitated vehicle routing problem is to find a routing schedule describing the order in which geographically dispersed customers are visited to satisfy demand by supplying goods stored at the depot, such that the traveling costs are minimized. In many practical applications, a long
Lagrangian duality applied to the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Kallehauge, Brian; Larsen, Jesper; Madsen, Oli B.G.
2006-01-01
This paper considers the vehicle routing problem with time windows, where the service of each customer must start within a specified time interval. We consider the Lagrangian relaxation of the constraint set requiring that each customer must be served by exactly one vehicle yielding a constrained...
The Time-Dependent Multiple-Vehicle Prize-Collecting Arc Routing Problem
DEFF Research Database (Denmark)
Black, Daniel; Eglese, Richard; Wøhlk, Sanne
2015-01-01
In this paper, we introduce a multi vehicle version of the Time-Dependent Prize-Collecting Arc Routing Problem (TD-MPARP). It is inspired by a situation where a transport manager has to choose between a number of full truck load pick-ups and deliveries to be performed by a fleet of vehicles. Real...
Solving the Generalized Vehicle Routing Problem with an ACS-based Algorithm
Pop, Petrica Claudiu; Pintea, Camelia; Zelina, Ioana; Dumitrescu, Dan
2009-04-01
Ant colony system is a metaheuristic algorithm inspired by the behavior of real ants and was proposed by Dorigo et al. as a method for solving hard combinatorial optimization problems. In this paper we show its successful application to solving a network design problem: Generalized Vehicle Routing Problem. The Generalized Vehicle Routing Problem (GVRP) is the problem of designing optimal delivery or collection routes, subject to capacity restrictions, from a given depot to a number of predefined, mutually exclusive and exhaustive clusters. Computational results for several benchmark problems are reported.
Mass Transport Vehicle Routing Problem (MTVRP) and the Associated Network Design Problem (MTNDP)
2005-01-01
This research studies a new class of dynamic problem MTVRP where n vehicles are routed in real time in a fast varying environment to pickup and deliver m passengers when both n and m are big. The problem is very relevant to future transportation options involving large scale real-time routing of shared-ride fleet transit vehicles. Traditionally, dynamic routing solutions were found as static approximations for smaller-scale problems or using local heuristics for the larger-scale ones. General...
Genetic Algorithm and Tabu Search for Vehicle Routing Problems with Stochastic Demand
Ismail, Zuhaimy; Irhamah
2010-11-01
This paper presents a problem of designing solid waste collection routes, involving scheduling of vehicles where each vehicle begins at the depot, visits customers and ends at the depot. It is modeled as a Vehicle Routing Problem with Stochastic Demands (VRPSD). A data set from a real world problem (a case) is used in this research. We developed Genetic Algorithm (GA) and Tabu Search (TS) procedure and these has produced the best possible result. The problem data are inspired by real case of VRPSD in waste collection. Results from the experiment show the advantages of the proposed algorithm that are its robustness and better solution qualities.
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Teodor Dimitrov Berov
2016-06-01
Full Text Available This article presents a system aimed at generating optimized vehicles routes - the vehicle routing problem with time windows (VRPTW based on using a Google Maps™ network data and imperialist competitive algorithm meta-heuristic. The vehicle routing problem with time windows is an important problem in the supply chain management. It copes with route scheduling and the distribution of goods from the distribution center to geographically dispersed customers in urban areas by a fleet of vehicles with constrained capacities. The system was tested for urban goods distribution in Sofia, Bulgaria - 35 retailers, warehouse, two types of vehicles (capacity and a working day.
DEFF Research Database (Denmark)
Christensen, Jonas Mark; Røpke, Stefan
The Vehicle Routing Problem with Time Windows (VRPTW) consist of determining a set of feasible vehicle routes to deliver goods to a set of customers using a hierarchical objective; first minimising the number of vehicles used and, second, the total driving distance. A three-stage method is proposed...
Two-Phase Heuristic for the Vehicle Routing Problem with Time Windows
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Sándor Csiszár
2007-08-01
Full Text Available The subject of the paper is a complete solution for the vehicle routing problemwith time windows, an industrial realization of an NP hard combinatorial optimizationproblem. The primary objective –the minimization of the number of routes- is aimed in thefirst phase, the secondary objective –the travel distance minimization- is going to berealized in the second phase by tabu search. The initial route construction applies aprobability density function for seed selection. Guided Route Elimination procedure wasalso developed. The solution was tested on the Solomon Problem Set and seems to be verycompeitive with the best heuristics published in the latest years (2003-2005.
Northwest passage: Trade route for large air cushion vehicles
Anderson, J. L.
1973-01-01
A conceptual vehicle and powerplant (10,000-ton) nuclear-powered air-cushion vehicle (ACV) that could open the Northwest Passage and other Arctic passages to commercial traffic is identified. The report contains a description of the conceptual vehicle, including the powerplant and operations, an assessment of technical feasibility, estimates of capital and operating costs, and identification of eligible cargo and markets. A comparison of the nuclear ACV freighter with nuclear container ships shows that for containerized or roll-on/roll-off cargo the ACV would provide greatly reduced transit time between North Atlantic and North Pacific ports at a competitive cost.
Distributed stochastic multi-vehicle routing in the Euclidean plane with no communications
Pietrabissa, Antonio
2016-08-01
This paper presents an algorithm for the multi-vehicle routing problem with no communications among the vehicles. The scenario consists in a convex Euclidean mission space, where targets are generated according to a Poisson distribution in time and to a generic continuous spatial distribution. The targets must be visited by the vehicles, which, therefore, must act in coordination. Even if no communications are required, the proposed routing strategy succeeds in effectively partitioning the mission space among the vehicles: at low target generation rates, the algorithm leads to the well-known centroidal Voronoi tessellation, whereas at high target generation rates, simulation results show that it has better performances with respect to a reference algorithm with no communications among vehicles.
An exact algorithm for the vehicle routing problem with stochastic demands
Energy Technology Data Exchange (ETDEWEB)
Louveaux, F.
1994-12-31
The classical deterministic Vehicle Routing Problem (VRP) can be defined as follows. Let G = (V, E) be an undirected graph where V = {l_brace}v{sub 1}, {center_dot}{center_dot}, v{sub n}{r_brace} is a set of vertices representing cities or customers, and E = {l_brace}(v{sub i}, V{sub j}) : i < j; v{sub i}, v{sub j} {element_of} V{r_brace} is an edge set. With each vertex v{sub i}(i {>=} 2) (v{sub i}, v{sub j}) is associated a non-negative cost (distance, travel time) c{sub ij}. Vertex v{sub 1} represents a depot at which are based m identical vehicle of capacity Q > 0. Depending on the version of the problem considered, the value of m is either fixed, or bounded above by a constant {<=} m. The VRP consists of determining vehicle routes in such a way that (i) all routes start and end at the depot; (ii) each vertex other than the depot is visited exactly once; (iii) the total demand of any given route does not exceed Q; (iv) the total distance traveled by all vehicles is minimized. In the Stochastic Vehicle Routing Problem (SVRP), the demand associated with vertex v{sub i} is a random variable {xi}{sub i}. As a result, it is no longer possible to assume that vehicle routes may be followed as planned. The SRVP is modeled in two stages. In the first stage, a priori vehicle routes satisyfing conditions (i) and (ii) are constructed, without full information on the demands. In the second stage, when this information becomes available, routes are followed as planned, until the accumulated demand attains or exceeds the vehicle capacity. In this case, failure is said to occur and a recourse action is taken: the vehicle returns to the depot to unload, and resumes its visits at the point of failure. The SVRP consists of determining an a priori set of routes so as to minimize the expected cost of the second stage solution. The corresponding model can be solved using the relaxation approach in Laporte and Louveaux.
ROUTE OPTIMIZATION TO INCREASE ENERGY EFFICIENCY AND REDUCE FUEL CONSUMPTION OF COMMUNAL VEHICLES
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Nebojša M Jovičić
2010-01-01
Full Text Available Collection and transportation within the system of solid waste management may account more than 60% of the overall budget, most of which is for fuel costs. Furthermore, municipal vehicles have great environmental impact through exhaust gases emissions. The aim of this research was to estimate the potential for reduction of fuel consumption and thus the emission of CO2 through the communal vehicles route optimization. General methodology for route optimization is also presented. For the area under study, detailed field experimental research in the City of Kragujevac was conducted. Using GIS and GPS technology, whole municipally infrastructure for waste collection was scanned and all paths of communal tracks was recorded and allocated in developed database. Based on experimental and numerical results, one typical municipal vehicle route was analyzed by using ArcGis software. The obtained result indicates 2700 km of possible savings per year concerning one communal vehicle. In addition, the most fuel-economical route was extracted and compared with the original route, and with the routes extracted from criterions concerning the traffic time and shortest distance. According to available information for the City of Kragujevac and the results from this study, it was estimated that the total savings could be 20% in costs and the associated emissions.
A Meteheuristic Method for the Multi Trip Vehicle Routing Problem
2012-01-01
International audience; In recent years the number of passengers and freight vehicles increased in urban areas causing traffic congestion and increasing air and noise pollution. The need of an efficient distribution system that takes into account distribution cost, but at the same time considers environmental aspects aims the concept of city logistics. Vehicles could have limited capacity, due to laws restriction imposed and the narrowness of streets that characterize historical parts of down...
A Metaheuristic Method for the Multi Trip Vehicle Routing Problem
2012-01-01
National audience; In recent years the number of passengers and freight vehicles increased in urban areas causing traffic congestion and increasing air and noise pollution. The need of an efficient distribution system that takes into account distribution cost, but at the same time considers environmental aspects aims the concept of city logistics. Vehicles could have limited capacity, due to laws restriction imposed and the narrowness of streets that characterize historical parts of downtowns...
Route Assessment for Unmanned Aerial Vehicle Based on Cloud Model
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Xixia Sun
2014-01-01
Full Text Available An integrated route assessment approach based on cloud model is proposed in this paper, where various sources of uncertainties are well kept and modeled by cloud theory. Firstly, a systemic criteria framework incorporating models for scoring subcriteria is developed. Then, the cloud model is introduced to represent linguistic variables, and survivability probability histogram of each route is converted into normal clouds by cloud transformation, enabling both randomness and fuzziness in the assessment environment to be managed simultaneously. Finally, a new way to measure the similarity between two normal clouds satisfying reflexivity, symmetry, transitivity, and overlapping is proposed. Experimental results demonstrate that the proposed route assessment approach outperforms fuzzy logic based assessment approach with regard to feasibility, reliability, and consistency with human thinking.
Electric Vehicle Routing Problem with Charging Time and Variable Travel Time
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Sai Shao
2017-01-01
Full Text Available An electric vehicle routing problem with charging time and variable travel time is developed to address some operational issues such as range limitation and charging demand. The model is solved by using genetic algorithm to obtain the routes, the vehicle departure time at the depot, and the charging plan. Meanwhile, a dynamic Dijkstra algorithm is applied to find the shortest path between any two adjacent nodes along the routes. To prevent the depletion of all battery power and ensure safe operation in transit, electric vehicles with insufficient battery power can be repeatedly recharged at charging stations. The fluctuations in travel time are implemented to reflect a dynamic traffic environment. In conclusion, a large and realistic case study with a road network in the Beijing urban area is conducted to evaluate the model performance and the solution technology and analyze the results.
Vehicle Routing Problem Using Savings-Insertion and Reactive Tabu with a Variable Threshold
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Moussa Bagayoko
2016-12-01
Full Text Available This paper focuses on how the competitiveness of companies is impacted by products distribution and transportation costs, especially in the context of exports. This paper uses our two steps approach, consisting in building a good initial solution and then improving it to solve vehicle routing problem. To that end, first, our mathematical model is adapted; secondly, our Savings-insertion builds a good initial solution, and thirdly, our Reactive tabu with a variable threshold improves the initial solution. The objective is the minimization of the total distance of transport by respecting the specified time window and the demand of all customers, which are important for some transportation companies’. Finally, the experimental results obtained with our methodology for Solomon 100 customers 56 vehicle routing problems are provided and discussed. Our methodology provides the best solutions for problems types R2 and RC2. Therefore, using our methodology reduces the total distance for long-haul vehicle routing problems.
A Method of Vehicle Route Prediction Based on Social Network Analysis
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Ning Ye
2015-01-01
Full Text Available A method of vehicle route prediction based on social network analysis is proposed in this paper. The difference from proposed work is that, according to our collected vehicles’ past trips, we build a relationship model between different road segments rather than find the driving regularity of vehicles to predict upcoming routes. In this paper, firstly we depend on graph theory to build an initial road network model and modify related model parameters based on the collected data set. Then we transform the model into a matrix. Secondly, two concepts from social network analysis are introduced to describe the meaning of the matrix and we process it by current software of social network analysis. Thirdly, we design the algorithm of vehicle route prediction based on the above processing results. Finally, we use the leave-one-out approach to verify the efficiency of our algorithm.
Research on multi-objective emergency logistics vehicle routing problem under constraint conditions
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Miaomiao Du
2013-03-01
Full Text Available Purpose: Aim at choosing a relative good vehicle routing in emergency conditions under constraint conditions when disaster happens. Rapid response and rescue can save a lot of people. Design/methodology/approach: Modeling analysis: establishing a mathematical model of multi-objective emergency logistics vehicle routing problem. And in end of the paper, we intend to use genetic algorithms to solve the problem. Findings: Considering time requirement and cost limit both while choosing vehicle routing when the disasters happens is meaningful. We can get a relative good result and give a guidance to rescue teams. Originality/value: Consider cost and time objectives and kinds of realistic conditions (such as the road congestion in the model when solving the problem, having expanded the theory scope.
Directory of Open Access Journals (Sweden)
T.A. Yakovleva
2011-05-01
Full Text Available This paper is dealing with the vehicle routing problem, where different types of vehicles are managing to deliver different types of products. Three step heuristic with genetic algorithm is proposed for solving the problem.
MULTI-VEHICLE COVERING TOUR PROBLEM: BUILDING ROUTES FOR URBAN PATROLLING
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Washington Alves de Oliveira
2015-12-01
Full Text Available ABSTRACT In this paper we study a particular aspect of the urban community policing: routine patrol route planning. We seek routes that guarantee visibility, as this has a sizable impact on the community perceived safety, allowing quick emergency responses and providing surveillance of selected sites (e.g., hospitals, schools. The planning is restricted to the availability of vehicles and strives to achieve balanced routes. We study an adaptation of the model for the multi-vehicle covering tour problem, in which a set of locations must be visited, whereas another subset must be close enough to the planned routes. It constitutes an NP-complete integer programming problem. Suboptimal solutions are obtained with several heuristics, some adapted from the literature and others developed by us. We solve some adapted instances from TSPLIB and an instance with real data, the former being compared with results from literature, and latter being compared with empirical data.
Optimization of min-max vehicle routing problem based on genetic algorithm
Liu, Xia
2013-10-01
In some cases, there are some special requirements for the vehicle routing problem. Personnel or goods geographically scattered, should be delivered simultaneously to an assigned place by a fleet of vehicles as soon as possible. In this case the objective is to minimize the distance of the longest route among all sub-routes. An improved genetic algorithm was adopted to solve these problems. Each customer has a unique integer identifier and the chromosome is defined as a string of integers. Initial routes are constructed randomly, and then standard proportional selection incorporating elitist is chosen to guarantee the best member survives. New crossover and 2-exchange mutation is adopted to increase the diversity of group. The algorithm was implemented and tested on some instances. The results demonstrate the effectiveness of the method.
Layered Formulation for the Robust Vehicle Routing Problem with Time Windows
2012-01-01
International audience; This paper studies the vehicle routing problem with time windows where travel times are uncertain and belong to a predetermined polytope. The objective of the problem is to find a set of routes that services all nodes of the graph and that are feasible for all values of the travel times in the uncertainty polytope. The problem is motivated by maritime transportation where delays are frequent and must be taken into account. We present an extended formulation for the veh...
A savings based method for real-life vehicle routing problems
1999-01-01
textabstractThis paper describes a Savings Based algorithm for the Extended Vehicle Routing Problem. This algorithm is compared with a Sequential Insertion algorithm on real-life data. Besides the traditional quality measures such as total distance traveled and total workload, we compare the routing plans of both algorithms according to non-standard quality measures that help to evaluate the "visual attractiveness" of the plan. Computational results show that, in general, the Savings Based al...
A Variable Neighborhood Search-Based Heuristic for the Multi-Depot Vehicle Routing Problem
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Arif Imran
2013-01-01
Full Text Available The multi-depot vehicle routing problem (MDVRP is addressed using an adaptation of the variable neighborhood search (VNS. The proposed VNS algorithm besides using several neighborhoods and a number of local searches has a number of additional features. These include a scheme for identifying borderline customers, a diversivication procedure and a mechanism that aggregates and disaggregates routes between depots. The proposed algorithm is tested on the data instances from the literature and produces competitive results.
Formulations and Branch-and-Cut Algorithms for the Generalized Vehicle Routing Problem
DEFF Research Database (Denmark)
Bektas, Tolga; Erdogan, Günes; Røpke, Stefan
2011-01-01
The Generalized Vehicle Routing Problem (GVRP) consists of nding a set of routes for a number of vehicles with limited capacities on a graph with the vertices partitioned into clusters with given demands such that the total cost of travel is minimized and all demands are met. This paper offers four...... new integer linear programming formulations for the GVRP, two based on multicommodity flow and the other two based on exponential sets of inequalities. Branch-and-cut algorithms are proposed for the latter two. Computational results on a large set of instances are presented....
The electric vehicle routing problem with non-linear charging functions
2015-01-01
International audience; The use of electric vehicles (EVs) in freight and passenger transportation gives birth to a new family of vehicle routing problems (VRPs), the so-called electric VRPs (e-VRPs). As their name suggests, e-VRPs extend classical VRPs to account (mainly) for two constraining EV features: the short driving range and the long battery charging time. As a matter of fact, routes performed by EVs usually need to include time-consuming detours to charging stations. Most of the exi...
The vehicle routing problem with edge set costs
DEFF Research Database (Denmark)
Reinhardt, Line Blander; Jepsen, Mads Kehlet; Pisinger, David
. The certifications and contributions impose a cost for the company while they also give unlimited usage of a set of roads to all vehicles belonging to the company. Different versions for defining the edge sets are discussed and formulated. A MIP-formulation of the problem is presented, and a solution method based...
Single-Commodity Vehicle Routing Problem with Pickup and Delivery Service
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Goran Martinovic
2008-01-01
Full Text Available We present a novel variation of the vehicle routing problem (VRP. Single commodity cargo with pickup and delivery service is considered. Customers are labeled as either cargo sink or cargo source, depending on their pickup or delivery demand. This problem is called a single commodity vehicle routing problem with pickup and delivery service (1-VRPPD. 1-VRPPD deals with multiple vehicles and is the same as the single-commodity traveling salesman problem (1-PDTSP when the number of vehicles is equal to 1. Since 1-VRPPD specializes VRP, it is hard in the strong sense. Iterative modified simulated annealing (IMSA is presented along with greedy random-based initial solution algorithm. IMSA provides a good approximation to the global optimum in a large search space. Experiment is done for the instances with different number of customers and their demands. With respect to average values of IMSA execution times, proposed method is appropriate for practical applications.
A new memetic algorithm for solving split delivery vehicle routing problem
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Ali Bozorgi-Amiri
2015-11-01
Full Text Available Split delivery vehicle routing problem is one of the traditional types of routing problems in which the demand of different points can be divided among vehicles and the objective is to minimize the path length, which vehicles travel. In this paper, fuel cost of vehicles which is assumed to be dependent on their traveled path and load is considered as the objective functions. Namely, the cost of the consumed fuel is proportionate to the unit of load carried per unit of distance. In order to solve the proposed model a new memetic algorithm is developed which has two rows. The performance of the proposed algorithm for 21 standard problems is compared with the optimum solutions obtained from mathematical programming standard solver and the solutions of the same algorithm with single row solution representation. The results express the efficiency of developed algorithm.
Solving the vehicle routing problem by a hybrid meta-heuristic algorithm
Yousefikhoshbakht, Majid; Khorram, Esmaile
2012-08-01
The vehicle routing problem (VRP) is one of the most important combinational optimization problems that has nowadays received much attention because of its real application in industrial and service problems. The VRP involves routing a fleet of vehicles, each of them visiting a set of nodes such that every node is visited by exactly one vehicle only once. So, the objective is to minimize the total distance traveled by all the vehicles. This paper presents a hybrid two-phase algorithm called sweep algorithm (SW) + ant colony system (ACS) for the classical VRP. At the first stage, the VRP is solved by the SW, and at the second stage, the ACS and 3-opt local search are used for improving the solutions. Extensive computational tests on standard instances from the literature confirm the effectiveness of the presented approach.
Optimized Crossover Genetic Algorithm for Vehicle Routing Problem with Time Windows
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H. Nazif
2010-01-01
Full Text Available Problem statement: In this study, we considered the application of a genetic algorithm to vehicle routing problem with time windows where a set of vehicles with limits on capacity and travel time are available to service a set of customers with demands and earliest and latest time for serving. The objective is to find routes for the vehicles to service all the customers at a minimal cost without violating the capacity and travel time constraints of the vehicles and the time window constraints set by the customers. Approach: We proposed a genetic algorithm using an optimized crossover operator designed by a complete undirected bipartite graph that finds an optimal set of delivery routes satisfying the requirements and giving minimal total cost. Various techniques have also been introduced into the proposed algorithm to further enhance the solutions quality. Results: We tested our algorithm with benchmark instances and compared it with some other heuristics in the literature. The results showed that the proposed algorithm is competitive in terms of the quality of the solutions found. Conclusion/Recommendations: This study presented a genetic algorithm for solving vehicle routing problem with time windows using an optimized crossover operator. From the results, it can be concluded that the proposed algorithm is competitive when compared with other heuristics in the literature.
Hybrid tabu search for the multi-depot vehicle routing problem
Hu, Shan-Liang
2010-07-01
A hybrid tabu search for the multi-depot vehicle routing problem is considered in this paper. The purpose of the proposed approach is to decrease the number of used vehicles and the total travel cost. An extensive numerical experiment was performed on benchmark problem instances available in literature, the computational results are presented to show the high effectiveness and performance of the proposed approaches.
Optimal Routing and Charging of Electric Ride-Pooling Vehicles in Urban Networks
2016-01-01
In this project, we study an Electric Vehicle Routing Problem with Pick-ups and Deliveries, Time Windows, and Recharging Stations on New York City Taxicab data. In order to solve this problem, we divide the problems into three phases: (i) grouping similar customer requests by identifying geographic zones and time slots; (ii) determine groups of passengers to be transported together; (iii) complete the vehicle itinerary between these groups of passengers. The first phase uses the clustering me...
A Novel Heuristic Algorithm Based on Clark and Wright Algorithm for Green Vehicle Routing Problem
Mehdi Alinaghian; Zahra Kaviani; Siyavash Khaledan
2015-01-01
A significant portion of Gross Domestic Production (GDP) in any country belongs to the transportation system. Transportation equipment, in the other hand, is supposed to be great consumer of oil products. Many attempts have been assigned to the vehicles to cut down Greenhouse Gas (GHG). In this paper a novel heuristic algorithm based on Clark and Wright Algorithm called Green Clark and Wright (GCW) for Vehicle Routing Problem regarding to fuel consumption is presented. The objective function ...
Routing Autonomous Vehicles in the Improving Initial Task Assignment and Avoiding Deadlock Method
Morihiro, Yusuke; Miyamoto, Toshiyuki; Kumagai, Sadatoshi
This paper discusses an on-line Tasks Assignment and Routing Problem (TARP) for Autonomous Transportation Systems (ATSs) in manufacturing systems. The TARP is a constrained version of the Pickup and Delivery Problem with Time Windows (PDPTW). In our former study, a cooperative algorithm, called the triple loop method, with autonomous distributed agents has been proposed. The Improving initial Task Assignment and Avoiding Deadlock method (ITAAD) is a faster algorithm than the triple loop method. In this paper, we propose a new vehicle routing method for the ITAAD. Results of computational experiments show effectiveness of the proposed routing method.
Disjunctive cuts in a branch-and-price algorithm for the capacitated vehicle routing problem
DEFF Research Database (Denmark)
Røpke, Stefan
This talk presents computational results that show the usefulness of the general-purpose valid inequalities disjunctive cuts when applied to the CVRP. Results indicate that the disjunctive cuts are able to reduce the gap between lower bound and upper bound more than state-of-the-art problem speci...
The time-dependent two-echelon capacitated vehicle routing problem with environmental considerations
Soysal, M.; Bloemhof, J.M.; Bektas, T.
2015-01-01
Multi-echelon distribution strategies in which freight is delivered to customers via intermediate depots rather than direct shipments is an increasingly popular strategy in urban logistics. This is primarily to alleviate the environmental (e.g., energy usage and congestion) and social (e.g., traffic
A Branch-and-Cut Algorithm for the Capacitated Open Vehicle Routing Problem
DEFF Research Database (Denmark)
Letchford, Adam N.; Lysgaard, Jens; Eglese, Richard W.
-and-cut. We show that, even though the open CVRP initially looks like a minor variation of the standard CVRP, the integer programming formulation and cutting planes need to be modified in subtle ways. Computational results are given for several standard test instances, which enables us for the first time...... to assess the quality of existing heuristic methods, and to compare the relative difficulty of open and closed versions of the same problem....
Institute of Scientific and Technical Information of China (English)
Hiroshi; KISE; Mingzhe; LU; Guiyan; HU; Tan; LI
2002-01-01
This paper discusses an optimization of operating a p ermutation circulation-type vehicle routing system (PCVRS, for short), in w hich several stages are located along by a single loop, and a fleet of vehicles travels on the loop unidirectionally and repeatedly. Traveling on the loop, each vehicle receives an object from the loading stage and then carries it to a cert ain processing stage, or receives an object from a certain processing stage and then carries it to the unloading stage per a turnaround...
Kok, A.L.; Meyer, C.M.; Kopfer, H.; Schutten, J.M.J.
2010-01-01
In practice, apart from the problem of vehicle routing, schedulers also face the problem of finding feasible driver schedules complying with complex restrictions on drivers' driving and working hours. To address this complex interdependent problem of vehicle routing and break scheduling, we propose
Kok, A.L.; Hans, E.W.; Schutten, J.M.J.; Zijm, W.H.M.
2010-01-01
For the intensively studied vehicle routing problem (VRP), two real-life restrictions have received only minor attention in the VRP-literature: traffic congestion and driving hours regulations. Traffic congestion causes late arrivals at customers and long travel times resulting in large transport co
Metaheuristics applied to vehicle routing. A case study. Parte 1: formulating the problem
Directory of Open Access Journals (Sweden)
Guillermo González Vargas
2010-04-01
Full Text Available This paper deals with VRP (vehicle routing problem mathematical formulation and presents some methodologies used by different authors to solve VRP variation. This paper is presented as the springboard for introducing future papers about a manufacturing company’s location decisions based on the total distance traveled to distribute its product.
Determining which Orders to Outsource in the Vehicle Routing Problem with Order Outsourcing
Huijink, Sybren; Kant, Goos; Peeters, Rene
2015-01-01
In practice, many package transportation companies lower their costs by hiring outside carriers to serve orders that cannot be served efficiently by their own trucks. The problem which takes the order outsource option into account is the Vehicle Routing Problem with Private Fleet and Common Carrier.
Vehicle Routing with Traffic Congestion and Drivers' Driving and Working Rules
Kok, A.L.; Hans, E.W.; Schutten, J.M.J.; Zijm, W.H.M.
2010-01-01
For the intensively studied vehicle routing problem (VRP), two real-life restrictions have received only minor attention in the VRP-literature: traffic congestion and driving hours regulations. Traffic congestion causes late arrivals at customers and long travel times resulting in large transport co
Subset-row inequalities applied to the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Jepsen, Mads Kehlet; Petersen, Bjørn; Spoorendonk, Simon;
2008-01-01
This paper presents a branch-and-cut-and-price algorithm for the vehicle-routing problem with time windows. The standard Dantzig-Wolfe decomposition of the arc flow formulation leads to a set-partitioning problem as the master problem and an elementary shortest-path problem with resource...
The Edge Set Cost of the Vehicle Routing Problem with Time Windows
DEFF Research Database (Denmark)
Reinhardt, Line Blander; Jepsen, Mads Kehlet; Pisinger, David
2016-01-01
We consider an important generalization of the vehicle routing problem with time windows in which a fixed cost must be paid for accessing a set of edges. This fixed cost could reflect payment for toll roads, investment in new facilities, the need for certifications, and other costly investments...
Constraint Programming based Local Search for the Vehicle Routing Problem with Time Windows
Sala Reixach, Joan
2012-01-01
El projecte es centra en el "Vehicle Routing Problem with Time Windows". Explora i testeja un mètode basat en una formulació del problema en termes de programació de restriccions. Implementa un mètode de cerca local amb la capacitat de fer grans moviments anomenat "Large Neighbourhood Search".
An Adaptable Variable Neighborhood Search for the Vehicle Routing Problem with Order Outsourcing
Huijink, S.; Kant, G.; Peeters, M.J.P.
2014-01-01
In practice, many package transportation companies lower their costs by hiring outside carriers to serve orders that cannot be served efficiently by their own trucks. The problem which takes the order outsource option into account is the Vehicle Routing Problem with Private Fleet and Common Carrier.
Stochastic time-dependent vehicle routing problem: Mathematical models and ant colony algorithm
Directory of Open Access Journals (Sweden)
Zhengyu Duan
2015-11-01
Full Text Available This article addresses the stochastic time-dependent vehicle routing problem. Two mathematical models named robust optimal schedule time model and minimum expected schedule time model are proposed for stochastic time-dependent vehicle routing problem, which can guarantee delivery within the time windows of customers. The robust optimal schedule time model only requires the variation range of link travel time, which can be conveniently derived from historical traffic data. In addition, the robust optimal schedule time model based on robust optimization method can be converted into a time-dependent vehicle routing problem. Moreover, an ant colony optimization algorithm is designed to solve stochastic time-dependent vehicle routing problem. As the improvements in initial solution and transition probability, ant colony optimization algorithm has a good performance in convergence. Through computational instances and Monte Carlo simulation tests, robust optimal schedule time model is proved to be better than minimum expected schedule time model in computational efficiency and coping with the travel time fluctuations. Therefore, robust optimal schedule time model is applicable in real road network.
Relative Performance of Certain Meta Heuristics on Vehicle Routing Problem with Time Windows
Directory of Open Access Journals (Sweden)
Sandhya
2015-11-01
Full Text Available —Solving Vehicle Routing Problem (VRP and its variants arise in many real life distribution systems. Classical VRP can be described as the problem of finding minimum cost routes with identical vehicles having fixed capacity which starts from a depot and reaches a number of customers with known demands with the proviso that each route starts and ends at the depot and the demand of each customer does not exceed the vehicle capacity is met. One of the generalizations of standard VRP is Vehicle Routing Problem with Time Windows (VRPTW with added complexity of serving every customer within a specified time window. Since VRPTW is a NP hard meta heuristics have often been designed for solving it. In this paper we compare the performance of Simulated Annealing (SA, genetic Algorithm (GA and Ant Colony Optimization (ACO for solving VRPTW based on their performance using different parameters taking total travel distance as the objective to be minimized. The results indicate that ACO is in general slightly more efficient then SA and GA.
Intention-Aware Routing to Minimise Delays at Electric Vehicle Charging Stations
De Weerdt, M.M.; Gerding, E.H.; Stein, S.; Robu, V.; Jennings, N.R.
2013-01-01
En-route charging stations allow electric vehicles to greatly extend their range. However, as a full charge takes a considerable amount of time, there may be significant waiting times at peak hours. To address this problem, we propose a novel navigation system, which communicates its intentions (i.
Opportunity costs calculation in agent-based vehicle routing and scheduling
Mes, Martijn; Heijden, van der Matthieu; Schuur, Peter
2006-01-01
In this paper we consider a real-time, dynamic pickup and delivery problem with timewindows where orders should be assigned to one of a set of competing transportation companies. Our approach decomposes the problem into a multi-agent structure where vehicle agents are responsible for the routing and
THREE-DIMENSIONAL LOADING VEHICLE ROUTING PROBLEM SOLUTION WITH SET-PARTITIONING-BASED METHOD
2013-01-01
The article considers the optimization problem of vehicle routing with three-dimensional loading constraints. Several practical loading constraints encountered in freight transportation are formalized. The efficiency of using the set-partitioning approach to improve heuristic solution is shown by means of computational experiment.
Vehicle routing for the eco-efficient collection of household plastic waste.
Bing, Xiaoyun; de Keizer, Marlies; Bloemhof-Ruwaard, Jacqueline M; van der Vorst, Jack G A J
2014-04-01
Plastic waste is a special category of municipal solid waste. Plastic waste collection is featured with various alternatives of collection methods (curbside/drop-off) and separation methods (source-/post-separation). In the Netherlands, the collection routes of plastic waste are the same as those of other waste, although plastic is different than other waste in terms of volume to weight ratio. This paper aims for redesigning the collection routes and compares the collection options of plastic waste using eco-efficiency as performance indicator. Eco-efficiency concerns the trade-off between environmental impacts, social issues and costs. The collection problem is modeled as a vehicle routing problem. A tabu search heuristic is used to improve the routes. Collection alternatives are compared by a scenario study approach. Real distances between locations are calculated with MapPoint. The scenario study is conducted based on real case data of the Dutch municipality Wageningen. Scenarios are designed according to the collection alternatives with different assumptions in collection method, vehicle type, collection frequency and collection points, etc. Results show that the current collection routes can be improved in terms of eco-efficiency performance by using our method. The source-separation drop-off collection scenario has the best performance for plastic collection assuming householders take the waste to the drop-off points in a sustainable manner. The model also shows to be an efficient decision support tool to investigate the impacts of future changes such as alternative vehicle type and different response rates.
Modelling of the optimal vehicle route in terrain in emergency situations using GIS data
Rybansky, M.
2014-02-01
Most navigation systems in transport are oriented towards the search for optimal paths (shortest or fastest), using vector GIS data. At the time of natural disasters and emergency situations is necessary to consider roads and terrain for transport. This article is focused on finding optimal routes in terrain, which contains a number of point, line and area obstacles. The most frequent point obstacles are trees in the forest. The paper analyzes the typical structure of tree stands in the forest, their characteristics in GIS databases, as well as dimensional parameters of vehicles moving in the forest. The quality of these data is a prerequisite for finding routes between point obstacles. Searching for the fastest or shortest route of the vehicle described in this article is based on the use of the relationship between the Delaunay triangulation and Voronoi graph, the application of Dijkstra's algorithm and the optimization of fractional line. The above-mentioned methods are also exploitable for searching for the shortest route of movement among line obstructions and area obstructions, such route can be apprehended as the joining of points defining impassable terrain. In such a case, the condition must be met that the distance of terminal points of joins has to be adjusted to the extent that it will be shorter than a vehicle width increased by safe margin.
Smith, Jordan Ned; Campbell, James A; Busby-Hjerpe, Andrea L; Lee, Sookwang; Poet, Torka S; Barr, Dana B; Timchalk, Charles
2009-06-30
Chlorpyrifos (CPF) is a commonly used organophosphorus pesticide. A number of toxicity and mechanistic studies have been conducted in animals, where CPF has been administered via a variety of different exposure routes and dosing vehicles. This study compared chlorpyrifos (CPF) pharmacokinetics using oral, intravenous (IV), and subcutaneous (SC) exposure routes and corn oil, saline/Tween 20, and dimethyl sulfoxide (DMSO) as dosing vehicles. Two groups of rats were co-administered target doses (5 mg/kg) of CPF and isotopically labeled CPF (L-CPF). One group was exposed by both oral (CPF) and IV (L-CPF) routes using saline/Tween 20 vehicle; whereas, the second group was exposed by the SC route using two vehicles, corn oil (CPF) and DMSO (L-CPF). A third group was only administered CPF by the oral route in corn oil. For all treatments, blood and urine time course samples were collected and analyzed for 3,5,6-trichloro-2-pyridinol (TCPy), and isotopically labeled 3,5,6-trichloro-2-pyridinol (L-TCPy). Peak TCPy/L-TCPy concentrations in blood (20.2 micromol/l), TCPy/L-TCPy blood AUC (94.9 micromol/lh), and percent of dose excreted in urine (100%) were all highest in rats dosed orally with CPF in saline/Tween 20 and second highest in rats dosed orally with CPF in corn oil. Peak TCPy concentrations in blood were more rapidly obtained after oral administration of CPF in saline/Tween 20 compared to all other dosing scenarios (>1.5 h). These results indicate that orally administered CPF is more extensively metabolized than systemic exposures of CPF (SC and IV), and vehicle of administration also has an effect on absorption rates. Thus, equivalent doses via different routes and/or vehicles of administration could potentially lead to different body burdens of CPF, different rates of bioactivation to CPF-oxon, and different toxic responses. Simulations using a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model for CPF are consistent with these possibilities
AUTOMATED GUIDED VEHICLE (AGV SYSTEMS AND ROUTING PROBLEM IN DEPOT MAINTENANCE
Directory of Open Access Journals (Sweden)
Fatih YİĞİT
2003-02-01
Full Text Available When full automation is realized in factory automation, material handing systems (MHS have a fairly important role. The most technological development among MHS's has been concentrated on Automated Guided Vehicle (AGV systems. An AGV is an unmanned vehicle capable of following an external guidance signal to deliver a unit load from destination to destination. Nowadays, there are a lot of applications lie along service sector to industrial sector because of flexibilities of AGVs. In this study, these subjects have been applied on the Army Aviation Depot Maintenance where aircraft's and aircraft parts can be maintained and overhauled is an application fields of AGV, requiring AGV numbers and AGV routing. The AGV routing problem and traveling sales person (TSP problems are identical problems; where the AGV routing problem is formulated as a zero one integer programming. Examples are presented to demonstrate the approach and LINGO has been used to solve the example.
Solving Practical Vehicle Routing Problem with Time Windows Using Metaheuristic Algorithms
Directory of Open Access Journals (Sweden)
Filip Taner
2012-07-01
Full Text Available This paper addresses the Vehicle Routing Problem with Time Windows (VRPTW and shows that implementing algorithms for solving various instances of VRPs can significantly reduce transportation costs that occur during the delivery process. Two metaheuristic algorithms were developed for solving VRPTW: Simulated Annealing and Iterated Local Search. Both algorithms generate initial feasible solution using constructive heuristics and use operators and various strategies for an iterative improvement. The algorithms were tested on Solomon’s benchmark problems and real world vehicle routing problems with time windows. In total, 44 real world problems were optimized in the case study using described algorithms. Obtained results showed that the same distribution task can be accomplished with savings up to 40% in the total travelled distance and that manually constructed routes are very ineffective.
Directory of Open Access Journals (Sweden)
C Hauman
2014-06-01
Full Text Available The vehicle routing problem with time windows is a widely studied problem with many real-world applications. The problem considered here entails the construction of routes that a number of identical vehicles travel to service different nodes within a certain time window. New benchmark problems with multi-objective features were recently suggested in the literature and the multi-objective optimisation cross-entropy method is applied to these problems to investigate the feasibility of the method and to determine and propose reference solutions for the benchmark problems. The application of the cross-entropy method to the multi-objective vehicle routing problem with soft time windows is investigated. The objectives that are evaluated include the minimisation of the total distance travelled, the number of vehicles and/or routes, the total waiting time and delay time of the vehicles and the makespan of a route.
Express company’s vehicle routing optimization by multiple-dynamic saving algorithm
Directory of Open Access Journals (Sweden)
Junchao Liu
2014-05-01
Full Text Available Purpose: According to the disorder in circulation commuting and crossover commuting of SF company which is the China’s largest private express delivery service provider, the study uses the Saving Algorithm to make the vehicle routing and resources optimized, on this basis, proposes innovative improvements with Saving Algorithm and then applies it in every distribution center of SF forming a "multi-dynamic" type of Saving Algorithm to ensure both cost savings and timeliness. This method can be generalized for all express company to get the vehicle routing optimized.Design/methodology/approach: As the special transportation requirements of express companies, this study optimizes the vehicle route based on Saving Algorithm, uses multiple-dynamic Saving Algorithm, and considers the timeliness requirements of the express company to achieve a balance of cost and timeliness.Findings: The main finding is that a new method proposed which there can be a balance improvement for both cost and timeliness to optimize the vehicle route of express company. Calculation example validates the effectiveness of the model established and solving method.Practical implications: It is a widespread practice that by setting up model and parameters for the objectives, express company can maintain the balances between cost and timeliness and achieve the optimized vehicle route.Originality/value: It proposes innovative improvements, takes SF express company as an example, with Saving Algorithm which can be applied in every distribution center of express company to ensure the balance improvement for both cost and timeliness, and has a great practical significance to the transportation network and path optimization of express companies.
Intelligent Iterated Local Search Methods for Solving Vehicle Routing Problem with Different Fleets
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
To solve vehicle routing problem with different fleets, two methodologies are developed. The first methodology adopts twophase strategy. In the first phase, the improved savings method is used to assign customers to appropriate vehicles. In the second phase, the iterated dynasearch algorithm is adopted to route each selected vehicle with the assigned customers. The iterated dynasearch algorithm combines dynasearch algorithm with iterated local search algorithm based on random kicks. The second methodplogy adopts the idea of cyclic transfer which is performed by using dynamic programming algorithm, and the iterated dynasearch algorithm is also embedded in it. The test results show that both methodologies generate better solutions than the traditional method, and the second methodology is superior to the first one.
A generalized multi-depot vehicle routing problem with replenishment based on LocalSolver
Directory of Open Access Journals (Sweden)
Ying Zhang
2015-01-01
Full Text Available In this paper, we consider the multi depot heterogeneous vehicle routing problem with time windows in which vehicles may be replenished along their trips. Using the modeling technique in a new-generation solver, we construct a novel formulation considering a rich series of constraint conditions and objective functions. Computation results are tested on an example comes from the real-world application and some cases obtained from the benchmark problems. The results show the good performance of local search method in the efficiency of replenishment system and generalization ability. The variants can be used to almost all kinds of vehicle routing problems, without much modification, demonstrating its possibility of practical use.
Vehicle Routing Problem with Backhaul, Multiple Trips and Time Window
Directory of Open Access Journals (Sweden)
Johan Oscar Ong
2011-01-01
Full Text Available Transportation planning is one of the important components to increase efficiency and effectiveness in the supply chain system. Good planning will give a saving in total cost of the supply chain. This paper develops the new VRP variants’, VRP with backhauls, multiple trips, and time window (VRPBMTTW along with its problem solving techniques by using Ant Colony Optimization (ACO and Sequential Insertion as initial solution algorithm. ACO is modified by adding the decoding process in order to determine the number of vehicles, total duration time, and range of duration time regardless of checking capacity constraint and time window. This algorithm is tested by using set of random data and verified as well as analyzed its parameter changing’s. The computational results for hypothetical data with 50% backhaul and mix time windows are reported.
Simanullang, Herlin
2013-01-01
Vehicle Routing Problem (VRP) is a problem of combinatorial optimization complexeses that has essential role in management distribution system which is aimed to minimize the needed cost, the cost is determined in relationship with the distance of route which is taken by the distribution vehicle. The characteristic from VRP is the use of vehicle in certain capacity and its activity is centralized in one depot to serve the customer on certain locations with certain known demand. ...
Spatial, temporal, and hybrid decompositions for large-scale vehicle routing with time windows
Energy Technology Data Exchange (ETDEWEB)
Bent, Russell W [Los Alamos National Laboratory
2010-01-01
This paper studies the use of decomposition techniques to quickly find high-quality solutions to large-scale vehicle routing problems with time windows. It considers an adaptive decomposition scheme which iteratively decouples a routing problem based on the current solution. Earlier work considered vehicle-based decompositions that partitions the vehicles across the subproblems. The subproblems can then be optimized independently and merged easily. This paper argues that vehicle-based decompositions, although very effective on various problem classes also have limitations. In particular, they do not accommodate temporal decompositions and may produce spatial decompositions that are not focused enough. This paper then proposes customer-based decompositions which generalize vehicle-based decouplings and allows for focused spatial and temporal decompositions. Experimental results on class R2 of the extended Solomon benchmarks demonstrates the benefits of the customer-based adaptive decomposition scheme and its spatial, temporal, and hybrid instantiations. In particular, they show that customer-based decompositions bring significant benefits over large neighborhood search in contrast to vehicle-based decompositions.
Bula, Gustavo Alfredo; Prodhon, Caroline; Gonzalez, Fabio Augusto; Afsar, H Murat; Velasco, Nubia
2017-02-15
This work focuses on the Heterogeneous Fleet Vehicle Routing problem (HFVRP) in the context of hazardous materials (HazMat) transportation. The objective is to determine a set of routes that minimizes the total expected routing risk. This is a nonlinear function, and it depends on the vehicle load and the population exposed when an incident occurs. Thus, a piecewise linear approximation is used to estimate it. For solving the problem, a variant of the Variable Neighborhood Search (VNS) algorithm is employed. To improve its performance, a post-optimization procedure is implemented via a Set Partitioning (SP) problem. The SP is solved on a pool of routes obtained from executions of the local search procedure embedded on the VNS. The algorithm is tested on two sets of HFVRP instances based on literature with up to 100 nodes, these instances are modified to include vehicle and arc risk parameters. The results are competitive in terms of computational efficiency and quality attested by a comparison with Mixed Integer Linear Programming (MILP) previously proposed.
Simulated annealing (SA to vehicle routing problems with soft time windows
Directory of Open Access Journals (Sweden)
Suphan Sodsoon
2014-12-01
Full Text Available The researcher has applied and develops the meta-heuristics method to solve Vehicle Routing Problems with Soft Time Windows (VRPSTW. For this case there was only one depot, multi customers which each generally sparse either or demand was different though perceived number of demand and specific period of time to receive them. The Operation Research was representative combinatorial optimization problems and is known to be NP-hard. In this research algorithm, use Simulated Annealing (SA to determine the optimum solutions which rapidly time solving. After developed the algorithms, apply them to examine the factors and the optimum extended time windows and test these factors with vehicle problem routing under specific time windows by Solomon in OR-Library in case of maximum 25 customers. Meanwhile, 6 problems are including of C101, C102, R101, R102, RC101 and RC102 respectively. The result shows the optimum extended time windows at level of 50%. At last, after comparison these answers with the case of vehicle problem routing under specific time windows and flexible time windows, found that percentage errors on number of vehicles approximately by -28.57% and percentage errors on distances approximately by -28.57% which this algorithm spent average processing time on 45.5 sec/problems.
A HYBRID GENETIC ALGORITHM IMPLEMENTATION FOR VEHICLE ROUTING PROBLEM WITH TIME WINDOWS
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Muhammad Faisal Ibrahim
2016-01-01
Full Text Available This article is related to approach development in order to determine the most appropriate route for bottled water delivery from warehouse to retail from particular boundaries such as a limit on number of vehicle, vehicle capacity, and time windows to each retail. A mathematical model of VRPTW is adopted to solve the problem. Malang is one of the drinking water production centers in Indonesia, definitely it will be difficult for the company to determine the optimal delivery route with the existing restrictions. In this research hybrid genetic algorithm is use to determine the route shipping companies with the Java programming language. After analyzing the results obtained show that the results of the implementation of hybrid genetic algorithm is better than the company actual route. Moreover, authors also analyze the effect the number of iterations for the computation time, and the influence the number of iterations for the fitness value or violation. This algorithm can be applied for the routing and the result obtained is an optimal solution
Routing of Electric Vehicles: Case Study of City Distribution in Copenhagen
DEFF Research Database (Denmark)
Linde, Esben; Larsen, Allan; Nørrelund, Anders Vedsted
In Copenhagen, Denmark, the preliminary steps of introducing an Urban Consolidation Centre (UCC) in the perimeter of the city centre has been taken. By implementing a UCC, interests of customers and distributors, as well as improvement of the local urban environment are sought considered [1...... a tour. Furthermore, intelligent location of these recharging points is considered. The objective is to find a least cost plan for routing and recharging the vehicles so that each customer is serviced by exactly one vehicle within its time windows and the vehicle capacity and driving range constraints......]. The UCC service aims to consolidate urban freight, as well as implement additional aspects such as off-peak delivery and utilisation of alternatively fuelled vehicles. In the specific case of Copenhagen, a comprehensive traffic survey was conducted in May 2011. The aim of the survey was to estimate...
Institute of Scientific and Technical Information of China (English)
HAN Lu; ZHOU Man-li; TIAN Jing; KURT Rothermel
2004-01-01
A new algorithm called spatially aware routing algorithm with enhanced learning (SAREL) is proposed to guarantee the rationality of route selecting in inter-vehicle communication scenario. Firstly, the traffic model is discussed and set up by using Poisson distribution. Then we analyze the process of traffic evaluation with enhanced learning, and exploit movement estimation to assist state memorization. The improvement of algorithm is provided at last compared with our previous work. Simulation results show that SAREL algorithm could achieve better performance in packet delivery ratio, especially when network connection ratio is average.
Integrated consensus-based frameworks for unmanned vehicle routing and targeting assignment
Barnawi, Waleed T.
Unmanned aerial vehicles (UAVs) are increasingly deployed in complex and dynamic environments to perform multiple tasks cooperatively with other UAVs that contribute to overarching mission effectiveness. Studies by the Department of Defense (DoD) indicate future operations may include anti-access/area-denial (A2AD) environments which limit human teleoperator decision-making and control. This research addresses the problem of decentralized vehicle re-routing and task reassignments through consensus-based UAV decision-making. An Integrated Consensus-Based Framework (ICF) is formulated as a solution to the combined single task assignment problem and vehicle routing problem. The multiple assignment and vehicle routing problem is solved with the Integrated Consensus-Based Bundle Framework (ICBF). The frameworks are hierarchically decomposed into two levels. The bottom layer utilizes the renowned Dijkstra's Algorithm. The top layer addresses task assignment with two methods. The single assignment approach is called the Caravan Auction Algorithm (CarA) Algorithm. This technique extends the Consensus-Based Auction Algorithm (CBAA) to provide awareness for task completion by agents and adopt abandoned tasks. The multiple assignment approach called the Caravan Auction Bundle Algorithm (CarAB) extends the Consensus-Based Bundle Algorithm (CBBA) by providing awareness for lost resources, prioritizing remaining tasks, and adopting abandoned tasks. Research questions are investigated regarding the novelty and performance of the proposed frameworks. Conclusions regarding the research questions will be provided through hypothesis testing. Monte Carlo simulations will provide evidence to support conclusions regarding the research hypotheses for the proposed frameworks. The approach provided in this research addresses current and future military operations for unmanned aerial vehicles. However, the general framework implied by the proposed research is adaptable to any unmanned
Model and Two-stage Algorithm on Dynamic Vehicle Routing Problem%一类动态车辆路径问题模型和两阶段算法
Institute of Scientific and Technical Information of China (English)
饶卫振; 金淳; 刘锋; 杨磊
2015-01-01
In order to effectively solve dynamic vehicle routing problem (DVRP), this paper analyzes the substantial effect of four main categories of dynamic information on classical vehicle routing problem, and transform DVRP into multiple static fleet size and mixed open vehicle routing problems (FSMOVRP). And FSMOVRP could be further converted to multiple capacitated vehicle routing problems (CVRP). The model based on CVRP is built up for DVRP. After that a two-stage algorithm is proposed to solve DVRP model according to the analysis of DVRP characteristics. In the first stage, a fast construction algorithm with merely O(nlogn) complexity is proposed on the basis of delivery region cutting strategy by K-d trees method. In the second stage, a hybrid local search algorithm is designed by analysis of structural principal of algorithm’s solution searching space. Finally for the purpose of algorithm verification, we design and solve 36 DVRP instances generated from 12 large scale CVRP benchmark instances. The results demonstrate the effectiveness of the model and two-stage solving algorithm.%针对一类动态车辆路径问题，分析4种主要类型动态信息对传统车辆路径问题的本质影响，将动态车辆路径问题(Dynamic Vehicle Routing Problem, DVRP)转化为多个静态的多车型开放式车辆路径问题(The Fleet Size and Mixed Open Vehicle Routing Problem, FSMOVRP)，并进一步转化为多个带能力约束车辆路径问题(Capacitated Vehicle Routing Problem, CVRP)，基于CVRP模型建立了DVRP模型；然后，在分析DVRP问题特点基础上，提出两阶段算法，第一阶段基于利用K-d trees对配送区域进行分割的策略，提出了复杂度仅为O(nlogn)的快速构建型算法，第二阶段通过分析算法搜索解空间结构原理，设计混合局部搜索算法；最后，基于现有12个大规模CVRP标准算例，设计并求解36个DVRP算例。求解结果表明了模型和两阶段算法的有效性。
Directory of Open Access Journals (Sweden)
Ika Ayu Fajarwati
2012-09-01
Full Text Available Vehicle Routing Problem (VRP merupakan permasalahan optimasi kombinatorial kompleks yang memiliki peranan penting dalam manajemen sistem distribusi dengan tujuan meminimalkan biaya yang diperlukan, dimana penentuan biaya berkaitan dengan jarak dari rute yang ditempuh oleh armada distribusi. Ciri dari VRP yaitu penggunaan armada dengan kapasitas tertentu dan kegiatannya berpusat pada satu titik depot untuk melayani pelanggan pada titik-titik tertentu dengan jumlah permintaan yang diketahui. Kasus distribusi yang menggabungkan aktifitas pengiriman dan pengambilan produk termasuk dalam salah satu jenis VRP yaitu Vehicle Routing Problem Delivery and Pick-Up (VRP-DP. Banyak metode yang dapat digunakan untuk menyelesaikan permasalahan VRP-DP, salah satunya adalah metode optimasi metaheuristik yaitu Algoritma Differential Evolution yang akan diperkenalkan dalam penelitian ini. Hasil yang diharapkan nantinya adalah rute distribusi optimal untuk armada perusahaan sehingga menghasilkan jarak tempuh dan tentunya total biaya yang minimal dalam memenuhi semua permintaan pelanggan
A framework for the interactive resolution of multi-objective vehicle routing problems
Geiger, Martin Josef
2008-01-01
The article presents a framework for the resolution of rich vehicle routing problems which are difficult to address with standard optimization techniques. We use local search on the basis on variable neighborhood search for the construction of the solutions, but embed the techniques in a flexible framework that allows the consideration of complex side constraints of the problem such as time windows, multiple depots, heterogeneous fleets, and, in particular, multiple optimization criteria. In order to identify a compromise alternative that meets the requirements of the decision maker, an interactive procedure is integrated in the resolution of the problem, allowing the modification of the preference information articulated by the decision maker. The framework is prototypically implemented in a computer system. First results of test runs on multiple depot vehicle routing problems with time windows are reported.
The vehicle routing game: An application of cost allocation in a gas and oil company
Energy Technology Data Exchange (ETDEWEB)
Engevall, Stefan; Goethe-Lundgren, Maud; Vaerbrand, Peter
2000-12-01
In this article we study a cost allocation problem that arises in a distribution planning situation at the Logistics department at Norsk Hydro Olje AB. The routes from one depot during one day are considered, for which the total distribution cost is to be divided among the customers that are visited. This cost allocation problem is formulated as a vehicle routing game, allowing the use of vehicles with different capacities. Cost allocation methods based on different concepts from cooperative game theory, such as the core and the nucleolus, are discussed. A procedure that can be used to investigate whether the core is empty or not is presented, as well as a procedure to compute the nucleolus. Computational results for the Norsk Hydro case are also presented and discussed.
Multi-depot Vehicle Routing Problem with Pickup and Delivery Requests
Sombuntham, Pandhapon; Kachitvichyanukul, Voratas
2010-10-01
This paper considers a multi-depot vehicle routing problem with pickup and delivery requests. In the problem of interest, each location may have goods for both pickup and delivery with multiple delivery locations that may not be the depots. These characteristics are quite common in industrial practice. A particle swarm optimization algorithm with multiple social learning structures is proposed for solving the practical case of multi-depot vehicle routing problem with simultaneous pickup and delivery and time window. A new decoding procedure is implemented using the PSO class provided in the ETLib object library. Computational experiments are carried out using the test instances for the pickup and delivery problem with time windows (PDPTW) as well as a newly generated instance. The preliminary results show that the proposed algorithm is able to provide good solutions to most of the test problems.
Lagrangean Duality Applied on Vehicle Routing with Time Windows - Experimental Results
DEFF Research Database (Denmark)
Kallehauge, Brian; Larsen, Jesper; Madsen, Oli B.G.
2001-01-01
This report presents the results of the application of a non-differentiable optimization method in connection with the Vehicle Routing Problem with Time Windows (VRPTW). The VRPTW is an extension of the Vehicle Routing Problem. In the VRPTW the service at each customer must start within...... an associated time window. The Shortest Path decomposition of the VRPTW by Lagrangian relaxation require the finding of the optimal Lagrangian multipliers. This problem is a convex non-differentiable optimization problem. The optimal multipliers are found using the non-differentiable method denoted the proximal...... bundle- and Dantzig-Wolfe algorithm has been tested on the well-known Solomon VRPTW benchmark problems and a range of extended Solomon problems. Since we have succeded in solving 14 previously unsolved problems and an extended Solomon problem with 1000 customers, which is the largest problem ever solved...
A Hybrid Genetic Algorithm for Vehicle Routing Problem with Complex Constraints
Institute of Scientific and Technical Information of China (English)
CHEN Yan; LU Jun; LI Zeng-zhi
2006-01-01
Most research on the Vehicle Routing Problem (VRP) is focused on standard conditions, which is not suitable for specific cases. A Hybrid Genetic Algorithm is proposed to solve a Vehicle Routing Problem (VRP) with complex side constraints. A novel coding method is designed especially for side constraints. A greedy algorithm combined with a random algorithm is introduced to enable the diversity of the initial population, as well as a local optimization algorithm employed to improve the searching efficiency. In order to evaluate the performance, this mechanism has been implemented in an oil distribution center, the experimental and executing results show that the near global optimal solution can be easily and quickly obtained by this method, and the solution is definitely satisfactory in the VRP application.
Formulations and exact algorithms for the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Kallehauge, Brian
2008-01-01
In this paper we review the exact algorithms proposed in the last three decades for the solution of the vehicle routing problem with time windows (VRPTW). The exact algorithms for the VRPTW are in many aspects inherited from work on the traveling salesman problem (TSP). In recognition of this fact...... with the analysis of the polyhedral structure of the VRPTW. We conclude by examining possible future lines of research in the area of the VRPTW....
The vehicle routing problem: State of the art classification and review
Braekers, Kris; Ramaekers, Katrien; Van Nieuwenhuyse, Inneke
2016-01-01
Over the past decades, the Vehicle Routing Problem (VRP) and its variants have grown ever more popular in the academic literature. Yet, the problem characteristics and assumptions vary widely and few literature reviews have made an effort to classify the existing articles accordingly. In this article, we present a taxonomic review of the VRP literature published between 2009 and June 2015. Based on an adapted version of an existing comprehensive taxonomy, we classify 277 articles and analyze ...
The Edge Set Cost of the Vehicle Routing Problem with Time Windows
DEFF Research Database (Denmark)
Reinhardt, Line Blander; Jepsen, Mads Kehlet; Pisinger, David
2016-01-01
We consider an important generalization of the vehicle routing problem with time windows in which a fixed cost must be paid for accessing a set of edges. This fixed cost could reflect payment for toll roads, investment in new facilities, the need for certifications, and other costly investments...... results show that instances with up to 40 customers can be solved in a reasonable time, and that the branch-cut-and-price algorithm generally outperforms CPLEX....
A set-covering based heuristic algorithm for the periodic vehicle routing problem.
Cacchiani, V; Hemmelmayr, V C; Tricoire, F
2014-01-30
We present a hybrid optimization algorithm for mixed-integer linear programming, embedding both heuristic and exact components. In order to validate it we use the periodic vehicle routing problem (PVRP) as a case study. This problem consists of determining a set of minimum cost routes for each day of a given planning horizon, with the constraints that each customer must be visited a required number of times (chosen among a set of valid day combinations), must receive every time the required quantity of product, and that the number of routes per day (each respecting the capacity of the vehicle) does not exceed the total number of available vehicles. This is a generalization of the well-known vehicle routing problem (VRP). Our algorithm is based on the linear programming (LP) relaxation of a set-covering-like integer linear programming formulation of the problem, with additional constraints. The LP-relaxation is solved by column generation, where columns are generated heuristically by an iterated local search algorithm. The whole solution method takes advantage of the LP-solution and applies techniques of fixing and releasing of the columns as a local search, making use of a tabu list to avoid cycling. We show the results of the proposed algorithm on benchmark instances from the literature and compare them to the state-of-the-art algorithms, showing the effectiveness of our approach in producing good quality solutions. In addition, we report the results on realistic instances of the PVRP introduced in Pacheco et al. (2011) [24] and on benchmark instances of the periodic traveling salesman problem (PTSP), showing the efficacy of the proposed algorithm on these as well. Finally, we report the new best known solutions found for all the tested problems.
2002-06-01
Assignment Heurisitic for Vehicle Routing,” Networks: 11, 109-124 (1981). Fraleigh , John B. A First Course in Abstract Algebra, Addison-Wesley...Infantry Officer, and attended the Infantry Officer Basic Course and Ranger School. His first tour was with the 25th Infantry Division, Schofield...James Moore, for his guidance and support throughout the course of this research effort. I would also like to thank my committee members Dr. Barnes
A hybrid differential evolution algorithm to vehicle routing problem with fuzzy demands
Erbao, Cao; Mingyong, Lai
2009-09-01
In this paper, the vehicle routing problem with fuzzy demands (VRPFD) is considered, and a fuzzy chance constrained program model is designed, based on fuzzy credibility theory. Then stochastic simulation and differential evolution algorithm are integrated to design a hybrid intelligent algorithm to solve the fuzzy chance constrained program model. Moreover, the influence of the dispatcher preference index on the final objective of the problem is discussed using stochastic simulation, and the best value of the dispatcher preference index is obtained.
Directory of Open Access Journals (Sweden)
Qi Hu
2013-04-01
Full Text Available State-of-the-art heuristic algorithms to solve the vehicle routing problem with time windows (VRPTW usually present slow speeds during the early iterations and easily fall into local optimal solutions. Focusing on solving the above problems, this paper analyzes the particle encoding and decoding strategy of the particle swarm optimization algorithm, the construction of the vehicle route and the judgment of the local optimal solution. Based on these, a hybrid chaos-particle swarm optimization algorithm (HPSO is proposed to solve VRPTW. The chaos algorithm is employed to re-initialize the particle swarm. An efficient insertion heuristic algorithm is also proposed to build the valid vehicle route in the particle decoding process. A particle swarm premature convergence judgment mechanism is formulated and combined with the chaos algorithm and Gaussian mutation into HPSO when the particle swarm falls into the local convergence. Extensive experiments are carried out to test the parameter settings in the insertion heuristic algorithm and to evaluate that they are corresponding to the data’s real-distribution in the concrete problem. It is also revealed that the HPSO achieves a better performance than the other state-of-the-art algorithms on solving VRPTW.
GREEDY NON-DOMINATED SORTING IN GENETIC ALGORITHM-II FOR VEHICLE ROUTING PROBLEM IN DISTRIBUTION
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
Vehicle routing problem in distribution (VRPD) is a widely used type of vehicle routing problem (VRP), which has been proved as NP-Hard, and it is usually modeled as single objective optimization problem when modeling. For multi-objective optimization model, most researches consider two objectives. A multi-objective mathematical model for VRP is proposed, which considers the number of vehicles used, the length of route and the time arrived at each client. Genetic algorithm is one of the most widely used algorithms to solve VRP. As a type of genetic algorithm (GA), non-dominated sorting in genetic algorithm-Ⅱ(NSGA-Ⅱ) also suffers from premature convergence and enclosure competition. In order to avoid these kinds of shortage, a greedy NSGA-Ⅱ (GNSGA-Ⅱ) is proposed for VRP problem. Greedy algorithm is implemented in generating the initial population, cross-over and mutation. All these procedures ensure that NSGA-Ⅱ is prevented from premature convergence and refine the performance of NSGA-Ⅱ at each step. In the distribution problem of a distribution center in Michigan, US, the GNSGA-Ⅱ is compared with NSGA-Ⅱ. As a result, the GNSGA-II is the most efficient one and can get the most optimized solution to VRP problem. Also, in GNSGA-II, premature convergence is better avoided and search efficiency has been improved sharply.
Effects of Vehicle Number Feedback in Multi-Route Intelligent Traffic Systems
Dong, Chuanfei; Ma, Xu; Wang, Binghong
We first study dynamics of traffic flow with real-time information and the influence of a new feedback strategy named Vehicle Number Feedback Strategy (VNFS) in a multi-route scenario in which dynamic information can be generated and displayed on the board (the board refers to a variable message sign where information on the routes is displayed) to guide road users to make a choice. In a multi-route scenario, our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting vehicle number feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e. Travel Time Feedback Strategy (TTFS), Mean Velocity Feedback Strategy (MVFS) and Congestion Coefficient Feedback Strategy (CCFS). We also discuss the influence of expected arrival rate (Vp) at the entrance on the average flux of each route, and we find that the flux adopting VNFS is always the largest at each Vp value among these four feedback strategies.
A memory structure adapted simulated annealing algorithm for a green vehicle routing problem.
Küçükoğlu, İlker; Ene, Seval; Aksoy, Aslı; Öztürk, Nursel
2015-03-01
Currently, reduction of carbon dioxide (CO2) emissions and fuel consumption has become a critical environmental problem and has attracted the attention of both academia and the industrial sector. Government regulations and customer demands are making environmental responsibility an increasingly important factor in overall supply chain operations. Within these operations, transportation has the most hazardous effects on the environment, i.e., CO2 emissions, fuel consumption, noise and toxic effects on the ecosystem. This study aims to construct vehicle routes with time windows that minimize the total fuel consumption and CO2 emissions. The green vehicle routing problem with time windows (G-VRPTW) is formulated using a mixed integer linear programming model. A memory structure adapted simulated annealing (MSA-SA) meta-heuristic algorithm is constructed due to the high complexity of the proposed problem and long solution times for practical applications. The proposed models are integrated with a fuel consumption and CO2 emissions calculation algorithm that considers the vehicle technical specifications, vehicle load, and transportation distance in a green supply chain environment. The proposed models are validated using well-known instances with different numbers of customers. The computational results indicate that the MSA-SA heuristic is capable of obtaining good G-VRPTW solutions within a reasonable amount of time by providing reductions in fuel consumption and CO2 emissions.
Improved Multi-Agent System for the Vehicle Routing Problem with Time Windows
Institute of Scientific and Technical Information of China (English)
DAN Zhenggang; CAI Linning; ZHENG Li
2009-01-01
The vehicle routing problem with time windows (VRPTW) involves assigning a fleet of limited ca-pacity vehicles to serve a set of customers without violating the capacity and time constraints. This paper presents a multi-agent model system for the VRPTW based on the internal behavior of agents and coordina-tion among the agents. The system presents a formal view of coordination using the traditional contract-net protocol (CNP) that relies on the basic loop of agent behavior for order receiving, order announcement, bid calculation, and order scheduling followed by order execution. An improved CNP method based on a vehicle selection strategy is used to reduce the number of negotiations and the negotiation time. The model is vali-dated using Solomon's benchmarks, with the results showing that the improved CNP uses only 30% as many negotiations and only 70% of the negotiation time of the traditional CNP.
A Novel Heuristic Algorithm Based on Clark and Wright Algorithm for Green Vehicle Routing Problem
Directory of Open Access Journals (Sweden)
Mehdi Alinaghian
2015-08-01
Full Text Available A significant portion of Gross Domestic Production (GDP in any country belongs to the transportation system. Transportation equipment, in the other hand, is supposed to be great consumer of oil products. Many attempts have been assigned to the vehicles to cut down Greenhouse Gas (GHG. In this paper a novel heuristic algorithm based on Clark and Wright Algorithm called Green Clark and Wright (GCW for Vehicle Routing Problem regarding to fuel consumption is presented. The objective function is fuel consumption, drivers, and the usage of vehicles. Being compared to exact methods solutions for small-sized problems and to Differential Evolution (DE algorithm solutions for large-scaled problems, the results show efficient performance of the proposed GCW algorithm.
Son, Le Hoang; Louati, Amal
2016-06-01
Municipal Solid Waste (MSW) collection is a necessary process in any municipality resulting in the quality-of-life, economic aspects and urban structuralization. The intrinsic nature of MSW collection relates to the development of effective vehicle routing models that optimize the total traveling distances of vehicles, the environmental emission and the investment costs. In this article, we propose a generalized vehicle routing model including multiple transfer stations, gather sites and inhomogeneous vehicles in time windows for MSW collection. It takes into account traveling in one-way routes, the number of vehicles per m(2) and waiting time at traffic stops for reduction of operational time. The proposed model could be used for scenarios having similar node structures and vehicles' characteristics. A case study at Danang city, Vietnam is given to illustrate the applicability of this model. The experimental results have clearly shown that the new model reduces both total traveling distances and operational hours of vehicles in comparison with those of practical scenarios. Optimal routes of vehicles on streets and markets at Danang are given. Those results are significant to practitioners and local policy makers.
Ant colony system (ACS with hybrid local search to solve vehicle routing problems
Directory of Open Access Journals (Sweden)
Suphan Sodsoon
2016-02-01
Full Text Available This research applied an Ant Colony System algorithm with a Hybrid Local Search to solve Vehicle Routing Problems (VRP from a single depot when the customers’ requirements are known. VRP is an NP-hard optimization problem and has usually been successfully solved optimum by heuristics. A fleet of vehicles of a specific capacity are used to serve a number of customers at minimum cost, without violating the constraints of vehicle capacity. There are meta-heuristic approaches to solve these problems, such as Simulated Annealing, Genetic Algorithm, Tabu Search and the Ant Colony System algorithm. In this case a hybrid local search was used (Cross-Exchange, Or-Opt and 2-Opt algorithm with an Ant Colony System algorithm. The Experimental Design was tested on 7 various problems from the data set online in the OR-Library. There are five different problems in which customers are randomly distributed with the depot in an approximately central location. The customers were grouped into clusters. The results are evaluated in terms of optimal routes using optimal distances. The experimental results are compared with those obtained from meta-heuristics and they show that the proposed method outperforms six meta-heuristics in the literature.
A two-stage heuristic method for vehicle routing problem with split deliveries and pickups
Institute of Scientific and Technical Information of China (English)
Yong WANG; Xiao-lei MA; Yun-teng LAO; Hai-yan YU; Yong LIU
2014-01-01
The vehicle routing problem (VRP) is a well-known combinatorial optimization issue in transportation and logistics network systems. There exist several limitations associated with the traditional VRP. Releasing the restricted conditions of traditional VRP has become a research focus in the past few decades. The vehicle routing problem with split deliveries and pickups (VRPSPDP) is particularly proposed to release the constraints on the visiting times per customer and vehicle capacity, that is, to allow the deliveries and pickups for each customer to be simultaneously split more than once. Few studies have focused on the VRPSPDP problem. In this paper we propose a two-stage heuristic method integrating the initial heuristic algorithm and hybrid heuristic algorithm to study the VRPSPDP problem. To validate the proposed algorithm, Solomon benchmark datasets and extended Solomon benchmark datasets were modified to compare with three other popular algorithms. A total of 18 datasets were used to evaluate the effectiveness of the proposed method. The computational results indicated that the proposed algorithm is superior to these three algorithms for VRPSPDP in terms of total travel cost and average loading rate.
On the Miller-Tucker-Zemlin Based Formulations for the Distance Constrained Vehicle Routing Problems
Kara, Imdat
2010-11-01
Vehicle Routing Problem (VRP), is an extension of the well known Traveling Salesman Problem (TSP) and has many practical applications in the fields of distribution and logistics. When the VRP consists of distance based constraints it is called Distance Constrained Vehicle Routing Problem (DVRP). However, the literature addressing on the DVRP is scarce. In this paper, existing two-indexed integer programming formulations, having Miller-Tucker-Zemlin based subtour elimination constraints, are reviewed. Existing formulations are simplified and obtained formulation is presented as formulation F1. It is shown that, the distance bounding constraints of the formulation F1, may not generate the distance traveled up to the related node. To do this, we redefine the auxiliary variables of the formulation and propose second formulation F2 with new and easy to use distance bounding constraints. Adaptation of the second formulation to the cases where new restrictions such as minimal distance traveled by each vehicle or other objectives such as minimizing the longest distance traveled is discussed.
Enhanced Direction Based Hazard Routing Protocol for Smooth Movement of Vehicles
Directory of Open Access Journals (Sweden)
Needhi Lathar
2016-02-01
Full Text Available Vehicular Ad hoc Network involves the movement of vehicles and the communication between them for their security. VANETs have many application areas. One of main applications of VANETs is to improve the driving safety. In various safety related applications, vehicular nodes constantly communicate with roadside equipments. Road Side Units (RSUs can sense the real time information about road conditions, animals straying and road blocks and passes all this hazardous related information to the vehicles approaching in its range. These alert messages enable the driver to take timely decisions in preventing from accidents or delays in information delivery. In this paper, Enhanced Direction based Hazard Routing Protocol and Ad Hoc On-demand Distance Vector protocols are used to avoid prevent vehicles from collision and to increase the coverage range of VANETs. These issues are resolved by bypass routing and a synchronized clock maintained with the RSUs respectively. To solve the issues and make the system more reliable we propose the roadside wireless sensor nodes along with vehicular nodes in the network. The RSUs are fixed at some distances and communicate with wireless sensors attached at vehicular nodes.
Vehicle Routing Problem for Fashion Supply Chains with Cross-Docking
Directory of Open Access Journals (Sweden)
Zhi-Hua Hu
2013-01-01
Full Text Available Cross-docking, as a strategy to reduce lead time and enhance the efficiency of the fashion supply chain, has attracted substantial attention from both the academy and the industry. Cross-docking is a critical part of many fashion and textiles supply chains in practice because it can help to achieve many supply chain strategies such as postponement. We consider a model where there are multiple suppliers and customers in a single cross-docking center. With such a model setting, the issue concerning the coordinated routing between the inbound and outbound routes is much more complex than many traditional vehicle routing problems (VRPs. We formulate the optimal route selection problems from the suppliers to the cross-docking center and from the cross-docking center to the customers as the respective VRPs. Based on the relationships between the suppliers and the customers, we integrate the two VRP models to optimize the overall traveling time, distance, and waiting time at the cross-docking center. In addition, we propose a novel mixed 0/1 integer linear programming model by which the complexity of the problem can be reduced significantly. As demonstrated by the simulation analysis, our proposed model can be solved very efficiently by a commonly used optimization software package.
The life and times of the Savings Method for Vehicle Routing Problems
Directory of Open Access Journals (Sweden)
GK Rand
2009-12-01
Full Text Available Forty five years ago, an academic and practitioner from the north of England published a method of tackling the vehicle routing problem (VRP in an American journal. Little could they have realised how the method they devised would still be a significant part of the research agenda nearly half a century later. Adaptations of their method are significant components in the analysis of the many different extensions to the problem that have been investigated. This paper provides the historical background to the development of the savings method and subsequent proposed variations to the basic savings formula and other improvements, and then charts the role the savings method has played in the investigation of VRPs with additional constraints. Some interesting examples of practical applications of the savings method are reported. Finally, comments are made on the use of the savings method in commercial routing packages.
Xu, Sheng-Hua; Liu, Ji-Ping; Zhang, Fu-Hao; Wang, Liang; Sun, Li-Jian
2015-08-27
A combination of genetic algorithm and particle swarm optimization (PSO) for vehicle routing problems with time windows (VRPTW) is proposed in this paper. The improvements of the proposed algorithm include: using the particle real number encoding method to decode the route to alleviate the computation burden, applying a linear decreasing function based on the number of the iterations to provide balance between global and local exploration abilities, and integrating with the crossover operator of genetic algorithm to avoid the premature convergence and the local minimum. The experimental results show that the proposed algorithm is not only more efficient and competitive with other published results but can also obtain more optimal solutions for solving the VRPTW issue. One new well-known solution for this benchmark problem is also outlined in the following.
Directory of Open Access Journals (Sweden)
Wan-Yu Liu
2014-07-01
Full Text Available Torespondto the reduction of greenhouse gas emissions and global warming, this paper investigates the minimal-carbon-footprint time-dependent heterogeneous-fleet vehicle routing problem with alternative paths (MTHVRPP. This finds a route with the smallestcarbon footprint, instead of the shortestroute distance, which is the conventional approach, to serve a number of customers with a heterogeneous fleet of vehicles in cases wherethere may not be only one path between each pair of customers, and the vehicle speed differs at different times of the day. Inheriting from the NP-hardness of the vehicle routing problem, the MTHVRPP is also NP-hard. This paper further proposes a genetic algorithm (GA to solve this problem. The solution representedbyour GA determines the customer serving ordering of each vehicle type. Then, the capacity check is used to classify multiple routes of each vehicle type, and the path selection determines the detailed paths of each route. Additionally, this paper improves the energy consumption model used for calculating the carbon footprint amount more precisely. Compared with the results without alternative paths, our experimental results show that the alternative path in this experimenthas a significant impact on the experimental results in terms of carbon footprint.
Vehicle Routing Problem Solving Method for a Cooperative Logistics Network by Using Multi-Stage GA
Onoyama, Takashi; Maekawa, Takuya; Kubota, Sen; Tsuruta, Setsuo; Komoda, Norihisa
A GA applied VRP (Vehicle Routing Problem) solving-method which realizes optimization of a cooperative logistics network is proposed. For this optimization a VRP solving-method that can obtain human expert-level solution, which realizes steady logistics operation, in interactive response time is required. The multi-stage GA enables to obtain the accurate solution under both hard and weak time constraints in interactive response time. Moreover, to realize the stable logistics operation, the daily fluctuation of shipping volume is taken into the fitness value of each individual in GA. The experimental result reveals the proposed method obtains the accurate solution that realizes the stable operation in interactive response time.
Improved Fractal Space Filling Curves Hybrid Optimization Algorithm for Vehicle Routing Problem
Directory of Open Access Journals (Sweden)
Yi-xiang Yue
2015-01-01
Full Text Available Vehicle Routing Problem (VRP is one of the key issues in optimization of modern logistics system. In this paper, a modified VRP model with hard time window is established and a Hybrid Optimization Algorithm (HOA based on Fractal Space Filling Curves (SFC method and Genetic Algorithm (GA is introduced. By incorporating the proposed algorithm, SFC method can find an initial and feasible solution very fast; GA is used to improve the initial solution. Thereafter, experimental software was developed and a large number of experimental computations from Solomon’s benchmark have been studied. The experimental results demonstrate the feasibility and effectiveness of the HOA.
Improved Fractal Space Filling Curves Hybrid Optimization Algorithm for Vehicle Routing Problem
Yue, Yi-xiang; Zhang, Tong; Yue, Qun-xing
2015-01-01
Vehicle Routing Problem (VRP) is one of the key issues in optimization of modern logistics system. In this paper, a modified VRP model with hard time window is established and a Hybrid Optimization Algorithm (HOA) based on Fractal Space Filling Curves (SFC) method and Genetic Algorithm (GA) is introduced. By incorporating the proposed algorithm, SFC method can find an initial and feasible solution very fast; GA is used to improve the initial solution. Thereafter, experimental software was developed and a large number of experimental computations from Solomon's benchmark have been studied. The experimental results demonstrate the feasibility and effectiveness of the HOA. PMID:26167171
车辆路径优化文献综述%Review on Vehicle Routing Optimizations
Institute of Scientific and Technical Information of China (English)
肖建辉
2010-01-01
车辆调度问题(VRP,Vehicle Routing Problem)是现代物流系统研究中的一项重要内容.选取合适的运输路线,可以加快对客户需求的响应速度,提高服务质量,降低服务商的运营成本.本文就车辆路径问题的模型和求解方法对前人的研究成果进行回顾与梳理.
Improved Fractal Space Filling Curves Hybrid Optimization Algorithm for Vehicle Routing Problem.
Yue, Yi-xiang; Zhang, Tong; Yue, Qun-xing
2015-01-01
Vehicle Routing Problem (VRP) is one of the key issues in optimization of modern logistics system. In this paper, a modified VRP model with hard time window is established and a Hybrid Optimization Algorithm (HOA) based on Fractal Space Filling Curves (SFC) method and Genetic Algorithm (GA) is introduced. By incorporating the proposed algorithm, SFC method can find an initial and feasible solution very fast; GA is used to improve the initial solution. Thereafter, experimental software was developed and a large number of experimental computations from Solomon's benchmark have been studied. The experimental results demonstrate the feasibility and effectiveness of the HOA.
Solving the Vehicle Routing Problem with Stochastic Demands via Hybrid Genetic Algorithm-Tabu Search
Directory of Open Access Journals (Sweden)
Z. Ismail
2008-01-01
Full Text Available This study considers a version of the stochastic vehicle routing problem where customer demands are random variables with known probability distribution. A new scheme based on a hybrid GA and Tabu Search heuristic is proposed for this problem under a priori approach with preventive restocking. The relative performance of the proposed HGATS is compared to each GA and TS alone, on a set of randomly generated problems following some discrete probability distributions. The problem data are inspired by real case of VRPSD in waste collection. Results from the experiment show the advantages of the proposed algorithm that are its robustness and better solution qualities resulted.
Clique inequalities applied to the vehicle routing problem with time windows
DEFF Research Database (Denmark)
Spoorendonk, Simon; Desaulniers, Guy
2010-01-01
This work presents an exact branch-cut-and-price algorithm for the vehicle routing problem with time windows (VRPTW) where the well-known clique inequalities are used as cutting planes defined on the set partitioning master problem variables. It shows how these cutting planes affect the dominance......, to our knowledge, this is a first attempt at incorporating for the VRPTW a set of valid inequalities specialized for the set partitioning polytope. Computational results show that the use of clique inequalities improves the lower bound at the root node of the search tree and reduces the number of nodes...
A hybrid metaheuristic for the time-dependent vehicle routing problem with hard time windows
Directory of Open Access Journals (Sweden)
N. Rincon-Garcia
2017-01-01
Full Text Available This article paper presents a hybrid metaheuristic algorithm to solve the time-dependent vehicle routing problem with hard time windows. Time-dependent travel times are influenced by different congestion levels experienced throughout the day. Vehicle scheduling without consideration of congestion might lead to underestimation of travel times and consequently missed deliveries. The algorithm presented in this paper makes use of Large Neighbourhood Search approaches and Variable Neighbourhood Search techniques to guide the search. A first stage is specifically designed to reduce the number of vehicles required in a search space by the reduction of penalties generated by time-window violations with Large Neighbourhood Search procedures. A second stage minimises the travel distance and travel time in an ‘always feasible’ search space. Comparison of results with available test instances shows that the proposed algorithm is capable of obtaining a reduction in the number of vehicles (4.15%, travel distance (10.88% and travel time (12.00% compared to previous implementations in reasonable time.
DEFF Research Database (Denmark)
Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.
2014-01-01
the converter for efficiently charging and discharging the capacitive actuator from 0 V to 2.5 kV and vice versa, respectively. The converter is used to drive a dielectric electro active polymer (DEAP) based capacitive incremental actuator, which has the potential to be used in automotive (e.g., EVs), space...
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Kenan Karagül
2014-07-01
Full Text Available In this study, Fleet Size and Mix Vehicle Routing Problem is considered in order to optimize the distribution of the tourists who have traveled between the airport and the hotels in the shortest distance by using the minimum cost. The initial solution space for the related methods are formed as a combination of Savings algorithm, Sweep algorithm and random permutation alignment. Then, two well-known solution methods named as Standard Genetic Algorithms and random search algorithms are used for changing the initial solutions. Computational power of the machine and heuristic algorithms are used instead of human experience and human intuition in order to solve the distribution problem of tourists coming to hotels in Alanya region from Antalya airport. For this case study, daily data of tourist distributions performed by an agency operating in Alanya region are considered. These distributions are then modeled as Vehicle Routing Problem to calculate the solutions for various applications. From the comparisons with the decision of a human expert, it is seen that the proposed methods produce better solutions with respect to human experience and insight. Random search method produces a solution more favorable in terms of time. As a conclusion, it is seen that, owing to the distribution plans offered by the obtained solutions, the agencies may reduce the costs by achieving savings up to 35%.
Jawarneh, Sana; Abdullah, Salwani
2015-01-01
This paper presents a bee colony optimisation (BCO) algorithm to tackle the vehicle routing problem with time window (VRPTW). The VRPTW involves recovering an ideal set of routes for a fleet of vehicles serving a defined number of customers. The BCO algorithm is a population-based algorithm that mimics the social communication patterns of honeybees in solving problems. The performance of the BCO algorithm is dependent on its parameters, so the online (self-adaptive) parameter tuning strategy is used to improve its effectiveness and robustness. Compared with the basic BCO, the adaptive BCO performs better. Diversification is crucial to the performance of the population-based algorithm, but the initial population in the BCO algorithm is generated using a greedy heuristic, which has insufficient diversification. Therefore the ways in which the sequential insertion heuristic (SIH) for the initial population drives the population toward improved solutions are examined. Experimental comparisons indicate that the proposed adaptive BCO-SIH algorithm works well across all instances and is able to obtain 11 best results in comparison with the best-known results in the literature when tested on Solomon's 56 VRPTW 100 customer instances. Also, a statistical test shows that there is a significant difference between the results.
An Inverse Robust Optimisation Approach for a Class of Vehicle Routing Problems under Uncertainty
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Liang Sun
2016-01-01
Full Text Available There is a trade-off between the total penalty paid to customers (TPC and the total transportation cost (TTC in depot for vehicle routing problems under uncertainty (VRPU. The trade-off refers to the fact that the TTC in depot inevitably increases when the TPC decreases and vice versa. With respect to this issue, the vehicle routing problem (VRP with uncertain customer demand and travel time was studied to optimise the TPC and the TTC in depot. In addition, an inverse robust optimisation approach was proposed to solve this kind of VRPU by combining the ideas of inverse optimisation and robust optimisation so as to improve both the TPC and the TTC in depot. The method aimed to improve the corresponding TTC of the robust optimisation solution under the minimum TPC through minimising the adjustment of benchmark road transportation cost. According to the characteristics of the inverse robust optimisation model, a genetic algorithm (GA and column generation algorithm are combined to solve the problem. Moreover, 39 test problems are solved by using an inverse robust optimisation approach: the results show that both the TPC and TTC obtained by using the inverse robust optimisation approach are less than those calculated using a robust optimisation approach.
Directory of Open Access Journals (Sweden)
P. L. N. U. Cooray
2017-01-01
Full Text Available During the last decade, tremendous focus has been given to sustainable logistics practices to overcome environmental concerns of business practices. Since transportation is a prominent area of logistics, a new area of literature known as Green Transportation and Green Vehicle Routing has emerged. Vehicle Routing Problem (VRP has been a very active area of the literature with contribution from many researchers over the last three decades. With the computational constraints of solving VRP which is NP-hard, metaheuristics have been applied successfully to solve VRPs in the recent past. This is a threefold study. First, it critically reviews the current literature on EMVRP and the use of metaheuristics as a solution approach. Second, the study implements a genetic algorithm (GA to solve the EMVRP formulation using the benchmark instances listed on the repository of CVRPLib. Finally, the GA developed in Phase 2 was enhanced through machine learning techniques to tune its parameters. The study reveals that, by identifying the underlying characteristics of data, a particular GA can be tuned significantly to outperform any generic GA with competitive computational times. The scrutiny identifies several knowledge gaps where new methodologies can be developed to solve the EMVRPs and develops propositions for future research.
A Framing Link Based Tabu Search Algorithm for Large-Scale Multidepot Vehicle Routing Problems
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Xuhao Zhang
2014-01-01
Full Text Available A framing link (FL based tabu search algorithm is proposed in this paper for a large-scale multidepot vehicle routing problem (LSMDVRP. Framing links are generated during continuous great optimization of current solutions and then taken as skeletons so as to improve optimal seeking ability, speed up the process of optimization, and obtain better results. Based on the comparison between pre- and postmutation routes in the current solution, different parts are extracted. In the current optimization period, links involved in the optimal solution are regarded as candidates to the FL base. Multiple optimization periods exist in the whole algorithm, and there are several potential FLs in each period. If the update condition is satisfied, the FL base is updated, new FLs are added into the current route, and the next period starts. Through adjusting the borderline of multidepot sharing area with dynamic parameters, the authors define candidate selection principles for three kinds of customer connections, respectively. Link split and the roulette approach are employed to choose FLs. 18 LSMDVRP instances in three groups are studied and new optimal solution values for nine of them are obtained, with higher computation speed and reliability.
Institute of Scientific and Technical Information of China (English)
吴丽荣; 胡祥培; 饶卫振
2013-01-01
车辆能量消耗不仅受到行驶距离的影响,还会受车辆载重量和车辆速度的影响.从节能低碳角度考虑,通过对带容量限制的物流配送车辆路径问题(capacitated vehicle routing problem,CVRP)的扩展,建立了以最小化燃料消耗为优化目标的CVRP模型(fuel-consumption-minimizing capacitated vehicle routing problem,FCM-CVRP);通过对比分析CVRP和FCM-CVRP的解空间以及求解复杂度发现,FCM-CVRP较CVRP更加难以求解;基于FCM-CVRP可行解的燃料消耗量值和车辆路径长度值之间的高度正相关关系,提出了求解FCM-CVRP的两阶段算法;并运用Benchmark算例验证了模型和求解算法的有效性.数据结果表明:与传统的CVRP相比,FCM-CVRP能够有效降低燃料消耗量,并在此基础上对物流配送公司提出管理上的相关建议.
An Endosymbiotic Evolutionary Algorithm for the Hub Location-Routing Problem
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Ji Ung Sun
2015-01-01
Full Text Available We consider a capacitated hub location-routing problem (HLRP which combines the hub location problem and multihub vehicle routing decisions. The HLRP not only determines the locations of the capacitated p-hubs within a set of potential hubs but also deals with the routes of the vehicles to meet the demands of customers. This problem is formulated as a 0-1 mixed integer programming model with the objective of the minimum total cost including routing cost, fixed hub cost, and fixed vehicle cost. As the HLRP has impractically demanding for the large sized problems, we develop a solution method based on the endosymbiotic evolutionary algorithm (EEA which solves hub location and vehicle routing problem simultaneously. The performance of the proposed algorithm is examined through a comparative study. The experimental results show that the proposed EEA can be a viable solution method for the supply chain network planning.
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Omprakash Kaiwartya
2015-01-01
Full Text Available A multiobjective dynamic vehicle routing problem (M-DVRP has been identified and a time seed based solution using particle swarm optimization (TS-PSO for M-DVRP has been proposed. M-DVRP considers five objectives, namely, geographical ranking of the request, customer ranking, service time, expected reachability time, and satisfaction level of the customers. The multiobjective function of M-DVRP has four components, namely, number of vehicles, expected reachability time, and profit and satisfaction level. Three constraints of the objective function are vehicle, capacity, and reachability. In TS-PSO, first of all, the problem is partitioned into smaller size DVRPs. Secondly, the time horizon of each smaller size DVRP is divided into time seeds and the problem is solved in each time seed using particle swarm optimization. The proposed solution has been simulated in ns-2 considering real road network of New Delhi, India, and results are compared with those obtained from genetic algorithm (GA simulations. The comparison confirms that TS-PSO optimizes the multiobjective function of the identified problem better than what is offered by GA solution.
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Michel Povlovitsch Seixas
2013-01-01
Full Text Available This study addresses a vehicle routing problem with time windows, accessibility restrictions on customers, and a fleet that is heterogeneous with regard to capacity and average speed. A vehicle can perform multiple routes per day, all starting and ending at a single depot, and it is assigned to a single driver whose total work hours are limited. A column generation algorithm is proposed. The column generation pricing subproblem requires a specific elementary shortest path problem with resource constraints algorithm to address the possibility for each vehicle performing multiple routes per day and to address the need to set the workday’s start time within the planning horizon. A constructive heuristic and a metaheuristic based on tabu search are also developed to find good solutions.
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Vanessa de Oliveira Ferreira
2012-08-01
Full Text Available In this work we consider a variant of the vehicle routing problem that allows the assignment of multiple deliverymen to one or more routes. A practical motivation for this variant arises, for example, in the distribution of beverages in highly dense urban areas, characterized by the difficulty in serving daily requests within regular working day hours with a single deliveryman per vehicle. We present a mathematical model and a savings algorithm in order to generate low cost routes that maximize the number of requests served in compliance with the maximum route time. The impact of the extra deliverymen on the solutions provided by the proposed heuristic is assessed by means of sets of generated examples based on classical instances of literature. It is also presented the results obtained by an adaptation of a tabu search approach from the literature.
Geiger, Martin Josef
2008-01-01
The article describes an investigation of the effectiveness of genetic algorithms for multi-objective combinatorial optimization (MOCO) by presenting an application for the vehicle routing problem with soft time windows. The work is motivated by the question, if and how the problem structure influences the effectiveness of different configurations of the genetic algorithm. Computational results are presented for different classes of vehicle routing problems, varying in their coverage with time windows, time window size, distribution and number of customers. The results are compared with a simple, but effective local search approach for multi-objective combinatorial optimization problems.
Tavakkoli-Moghaddam, Reza; Alinaghian, Mehdi; Salamat-Bakhsh, Alireza; Norouzi, Narges
2012-05-01
A vehicle routing problem is a significant problem that has attracted great attention from researchers in recent years. The main objectives of the vehicle routing problem are to minimize the traveled distance, total traveling time, number of vehicles and cost function of transportation. Reducing these variables leads to decreasing the total cost and increasing the driver's satisfaction level. On the other hand, this satisfaction, which will decrease by increasing the service time, is considered as an important logistic problem for a company. The stochastic time dominated by a probability variable leads to variation of the service time, while it is ignored in classical routing problems. This paper investigates the problem of the increasing service time by using the stochastic time for each tour such that the total traveling time of the vehicles is limited to a specific limit based on a defined probability. Since exact solutions of the vehicle routing problem that belong to the category of NP-hard problems are not practical in a large scale, a hybrid algorithm based on simulated annealing with genetic operators was proposed to obtain an efficient solution with reasonable computational cost and time. Finally, for some small cases, the related results of the proposed algorithm were compared with results obtained by the Lingo 8 software. The obtained results indicate the efficiency of the proposed hybrid simulated annealing algorithm.
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Ary Arvianto
2014-01-01
Full Text Available In this paper we developed a VRP model for multiple routes, multiple time windows for multiple products and heterogeneous vehicles. The solution were constructed using a heuristic approach, i.e, a sequential insertion algorithm. Additionally, this model is applied to solve fuel distributions for eight customers in East Nusa Tenggara. It needs two tankers with capacity of 4700 kilo liters, so that those distributions can be accomplished with a minimum number of vehicles, total completion time, and range of completion time. The result of this study shows that for a heterogeneous vehicles problem, a vehicle with the largest capacity may not necessarily be the vehicle that provides an optimal solution. Moreover, advance trials should be conducted by providing a limited number of tankers for each tanker capacity, so the description of heterogeneous vehicles becomes more visible. In the future research, the solution will be improved by utilizing relocation techniques.
A sequential insertion heuristic for the initial solution to a constrained vehicle routing problem
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JW Joubert
2006-06-01
Full Text Available The Vehicle Routing Problem (VRP is a well-researched problem in the Operations Research literature. It is the view of the authors of this paper that the various VRP variants have been researched in isolation. This paper embodies an attempt to integrate three specific variants of the VRP, namely the VRP with multiple time windows, the VRP with a heterogeneous fleet, and the VRP with double scheduling, into an initial solution algorithm. The proposed initial solution algorithm proves feasible for the integration, while the newly introduced concept of time window compatibility decreases the computational burden when using benchmark data sets from literature as a basis for efficiency testing. The algorithm also improves the quality of the initial solution for a number of problem classes.
Wang, Jiahai; Zhou, Ying; Wang, Yong; Zhang, Jun; Chen, C L Philip; Zheng, Zibin
2016-03-01
This paper investigates a practical variant of the vehicle routing problem (VRP), called VRP with simultaneous delivery and pickup and time windows (VRPSDPTW), in the logistics industry. VRPSDPTW is an important logistics problem in closed-loop supply chain network optimization. VRPSDPTW exhibits multiobjective properties in real-world applications. In this paper, a general multiobjective VRPSDPTW (MO-VRPSDPTW) with five objectives is first defined, and then a set of MO-VRPSDPTW instances based on data from the real-world are introduced. These instances represent more realistic multiobjective nature and more challenging MO-VRPSDPTW cases. Finally, two algorithms, multiobjective local search (MOLS) and multiobjective memetic algorithm (MOMA), are designed, implemented and compared for solving MO-VRPSDPTW. The simulation results on the proposed real-world instances and traditional instances show that MOLS outperforms MOMA in most of instances. However, the superiority of MOLS over MOMA in real-world instances is not so obvious as in traditional instances.
Branch and price for the time-dependent vehicle routing problem with time windows
DEFF Research Database (Denmark)
Dabia, Said; Van Woensel, Tom; De Kok, Ton
2013-01-01
solution methods to the DM-TDVRPTW are based on (meta-)heuristics. The decomposition of an arc-based formulation leads to a setpartitioning problem as the master problem, and a time-dependent shortest path problem with resource constraints as the pricing problem. The master problem is solved by means...... of column generation, and a tailored labeling algorithm is used to solve the pricing problem. We introduce new dominance criteria that allow more label dominance. For our numerical results, we modified Solomon's data sets by adding time dependency. Our algorithm is able to solve about 63% of the instances......This paper presents a branch-and-price algorithm for the time-dependent vehicle routing problem with time windows (TDVRPTW). We capture road congestion by considering time-dependent travel times, i.e., depending on the departure time to a customer, a different travel time is incurred. We consider...
Koloch, Grzegorz; Kaminski, Bogumil
2010-10-01
In the paper we examine a modification of the classical Vehicle Routing Problem (VRP) in which shapes of transported cargo are accounted for. This problem, known as a three-dimensional VRP with loading constraints (3D-VRP), is appropriate when transported commodities are not perfectly divisible, but they have fixed and heterogeneous dimensions. In the paper restrictions on allowable cargo positionings are also considered. These restrictions are derived from business practice and they extended the baseline 3D-VRP formulation as considered by Koloch and Kaminski (2010). In particular, we investigate how additional restrictions influence relative performance of two proposed optimization algorithms: the nested and the joint one. Performance of both methods is compared on artificial problems and on a big-scale real life case study.
Multi-trip vehicle routing and scheduling problem with time window in real life
Sze, San-Nah; Chiew, Kang-Leng; Sze, Jeeu-Fong
2012-09-01
This paper studies a manpower scheduling problem with multiple maintenance operations and vehicle routing considerations. Service teams located at a common service centre are required to travel to different customer sites. All customers must be served within given time window, which are known in advance. The scheduling process must take into consideration complex constraints such as a meal break during the team's shift, multiple travelling trips, synchronisation of service teams and working shifts. The main objective of this study is to develop a heuristic that can generate high quality solution in short time for large problem instances. A Two-stage Scheduling Heuristic is developed for different variants of the problem. Empirical results show that the proposed solution performs effectively and efficiently. In addition, our proposed approximation algorithm is very flexible and can be easily adapted to different scheduling environments and operational requirements.
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Marc Reimann
2014-05-01
Full Text Available Keen competition and increasingly demanding customers have forced companies to use their resources more efficiently and to integrate production and transportation planning. In the last few years more and more researchers have also focused on this challenging problem by trying to determine the complexity of the individual problems and then developing fast and robust algorithms to solve them. This paper reviews existing literature on integrated production and distribution decisions at the tactical and operational level, where the distribution part is modelled as some variation of the well-known Vehicle Routing Problem (VRP. The focus is thereby on problems that explicitly consider deliveries to multiple clients in a less-than-truckload fashion. In terms of the production decisions we distinguish in our review between tactical and operational production problems by considering lot-sizing/capacity allocation and scheduling models, respectively.
Modified artificial bee colony for the vehicle routing problems with time windows.
Alzaqebah, Malek; Abdullah, Salwani; Jawarneh, Sana
2016-01-01
The natural behaviour of the honeybee has attracted the attention of researchers in recent years and several algorithms have been developed that mimic swarm behaviour to solve optimisation problems. This paper introduces an artificial bee colony (ABC) algorithm for the vehicle routing problem with time windows (VRPTW). A Modified ABC algorithm is proposed to improve the solution quality of the original ABC. The high exploration ability of the ABC slows-down its convergence speed, which may due to the mechanism used by scout bees in replacing abandoned (unimproved) solutions with new ones. In the Modified ABC a list of abandoned solutions is used by the scout bees to memorise the abandoned solutions, then the scout bees select a solution from the list based on roulette wheel selection and replace by a new solution with random routs selected from the best solution. The performance of the Modified ABC is evaluated on Solomon benchmark datasets and compared with the original ABC. The computational results demonstrate that the Modified ABC outperforms the original ABC also produce good solutions when compared with the best-known results in the literature. Computational investigations show that the proposed algorithm is a good and promising approach for the VRPTW.
Chen, Xianshun; Feng, Liang; Ong, Yew Soon
2012-07-01
In this article, we proposed a self-adaptive memeplex robust search (SAMRS) for finding robust and reliable solutions that are less sensitive to stochastic behaviours of customer demands and have low probability of route failures, respectively, in vehicle routing problem with stochastic demands (VRPSD). In particular, the contribution of this article is three-fold. First, the proposed SAMRS employs the robust solution search scheme (RS 3) as an approximation of the computationally intensive Monte Carlo simulation, thus reducing the computation cost of fitness evaluation in VRPSD, while directing the search towards robust and reliable solutions. Furthermore, a self-adaptive individual learning based on the conceptual modelling of memeplex is introduced in the SAMRS. Finally, SAMRS incorporates a gene-meme co-evolution model with genetic and memetic representation to effectively manage the search for solutions in VRPSD. Extensive experimental results are then presented for benchmark problems to demonstrate that the proposed SAMRS serves as an efficable means of generating high-quality robust and reliable solutions in VRPSD.
A time-slotted on-demand routing protocol for mobile ad hoc unmanned vehicle systems
Forsmann, J. Hope; Hiromoto, Robert E.; Svoboda, John
2007-04-01
Successful deployment of Unmanned Vehicle Systems (UVS) in military operations has increased their popularity and utility. The ability to sustain reliable mobile ad hoc formations dramatically enhances the usefulness and performance of UVS. Formation movement increases the amount of ground coverage in less time, decreases fuel consumption of the individual nodes, and provides an avenue for mission expansion through cooperative maneuvers such as refueling. In this paper, we study the wireless communication demands that arise from formation and maintenance of UVS within the context of a mobile ad hoc network (MANET). A MANET in formation is typically characterized by tradeoffs between network congestion and the ability to maintain useable communication bandwidth. Maintenance of UVS formations requires each node in the network to be peer-aware, which places a heavy demand on inner node communication. In order to mitigate the inner node network congestion, we introduce a time-slotted communication protocol. The protocol assigns time-slots and allows the designated nodes to communicate directly with other peer-nodes. This approach has been introduced within the context of the Time-Slotted Aloha protocol for station-to-station communication. The approach taken here is to embed the time-slotted reservation protocol into a standard on-demand routing protocol to also address the need to reactively and proactively respond to formation maintenance. The time-slotted on-demand routing protocol is shown to eliminate collisions due to route determination and, therefore, enhance quality of service as well as ensure necessary support for formation movement. A worst-case scenario is described and simulations performed to comparatively demonstrate the advantages of the new protocol.
A Memetic Algorithm for the Vehicle Routing Problem with Cross Docking
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Sanae Larioui
2015-11-01
Full Text Available In this paper we address the VRPCD, in which a set of homogeneous vehicles are used to transport products from the suppliers to customers via a cross-dock. The products can be consolidated at the cross-dock but cannot be stored for very long as the cross-dock does not have long-term inventory-holding capabilities. The objective of the VRPCD is to minimize the total traveled distance while respecting time window constraints of suppliers and customers and a time horizon for the whole transportation operation. Rummaging through all the work of literature on vehicle routing problems with cross-docking, there is no work that considers that customer will receive its requests from several suppliers; this will be the point of innovation of this work. A heuristic and a memetic algorithm are used to solve the problem. The proposed algorithms are implemented and tested on data sets involving up to 200 nodes (customers and suppliers. The first results show that the memetic algorithm can produce high quality solutions.
Energy Technology Data Exchange (ETDEWEB)
Gendreau, M.; Seguin, R.; Laporte, G.
1995-10-01
This paper considers a version of the stochastic vehicle routing problem where customers are present with some probability and have random demands. A tabu search heuristic is developed for this problem. Comparisons with known optimal solutions indicate that the heuristic solves the problem to optimality in the vast majority of cases and deviations from optimality are almost always small.
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Michael Drexl
2013-11-01
Full Text Available This paper studies a simultaneous vehicle and crew routing and scheduling problem arising in long-distance road transport in Europe: Pickup-and-delivery requests have to be fulfilled over a multi-period planning horizon by a heterogeneous fleet of trucks and drivers. Typically, in the vehicle routing literature, a fixed assignment of a driver to a truck is assumed. In our approach, we abandon this assumption and allow truck/driver changes at geographically dispersed relay stations. This offers greater planning flexibility and allows a better utilization of trucks, but also creates intricate interdependencies between trucks and drivers and requires the synchronization of their routes. A solution heuristic based on a two-stage decomposition of the problem is developed, taking into account European Union social legislation for drivers, and computational experiments using real-world data provided by a major German forwarder are presented and analyzed. The obtained results suggest that for the vehicle and driver cost structure prevalent in Western Europe and for transport requests that are not systematically acquired to complement one another, no cost savings are possible through simultaneous vehicle and crew routing and scheduling, although no formal proof of this fact is possible.
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Hany Seidgar
2016-01-01
Full Text Available This paper investigates a scheduling combined manpower-vehicle routing problem with a central depot in and a set of multi-skilled manpower for serving to customers. Teams are in different range of competencies that it will affect the service time duration. Vehicles are in different moving speeds and costs and not all the vehicles are capable to move toward all the customers’ sites. The objective is to minimize the total cost of servicing, routing, and lateness penalties. This paper presents a mixed integer programming model and two meta-heuristic approaches of genetic algorithm (GA and artificial bee colony algorithm (ABC are developed to solve the generated problems. Furthermore, Taguchi experimental design method is applied to set the proper values of parameters. The available results show the higher performance of proposed GA compared with ABC, in quality of solutions.
2015-01-01
Optimization of on-demand transportation systems and ride-sharing services involves solving a class of complex vehicle routing problems with pickup and delivery with time windows (VRPPDTW). This paper first proposes a new time-discretized multi-commodity network flow model for the VRPPDTW based on the integration of vehicles carrying states within space-time transportation networks, so as to allow a joint optimization of passenger-to-vehicle assignment and turn-by-turn routing in congested tr...
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Moussa Bagayoko
2016-12-01
Full Text Available This paper focuses on how the competitiveness of forestry companies in Canada is impacted by forest products distribution and transportation costs, especially in the context of exports. We propose a new two steps approach, consisting in building a good initial solution and then improving it to solve multi-objective forest vehicle routing problem. The main objective of this paper is to solve a multi-objective forest vehicle routing problem using the Savings-insertion, followed by the Reactive tabu, with a variable threshold. To that end, first, a mathematical model is established; secondly, our new Savings-insertion builds a good initial solution, and thirdly, our new Reactive tabu with a variable threshold improves the initial solution. The three main objectives are the minimization of number of routes, the minimization of total distance and the minimization of total time by respecting the specified time window and the demand of all customers, which are sometimes important in this field. Finally, the experimental results obtained with our methodology for the named vehicle routing problem are provided and discussed.
动态车辆路径问题研究综述%Overview on Dynamic Vehicle Routing Problems
Institute of Scientific and Technical Information of China (English)
韩娟娟; 李永先
2015-01-01
The paper reviewed dynamic vehicle routing problem .DVRP was classified into SVRP and FVRP . The paper introduced research in recent years on models ,algorithms and simulationg of dynamic vehicle rou‐ting problems ,and summarizes characteristics of dynamic vehicle routing problem .Finally ,the paper pros‐pected future research orientations of dynamic vehicle routing problem .%指出了动态车辆路径问题是运筹学和组合优化领域的前沿研究方向，研究动态车辆路径问题具有重要的理论和现实意义。阐述了动态车辆问题（DVRP），根据动态信息的特征将动态车辆路径问题分为随机车辆路径问题（SVRP）和模糊车辆路径问题（FVRP）。从动态车辆路径问题的建模、算法和仿真优化三个方面分析了其研究成果，对现有研究的不足进行了探讨，提出了动态车辆路径问题的进一步研究方向。
Vehicle Route Replanning for Fruit and Vegetable Delivery%果蔬运输车辆路径再规划
Institute of Scientific and Technical Information of China (English)
黄华芳; 王以忠; 李达; 门建婷; 张平; 黄国全
2012-01-01
果蔬具有易腐性,在销售、消费时存在很强的时效性,这就要求合理规划果蔬运输车辆的配送路径.在果蔬配送途中,当某运输车遇到特殊情况无法按时送达配送点时,应当对其他运输车进行路径再规划.给出了带时间窗的果蔬运输车辆路径再规划的数学模型,并采用改进蚁群算法进行了求解.仿真试验结果表明,模型及算法可以有效地优化果蔬配送新路线,为降低果蔬腐烂损失、提高销售收入、有效控制运作成本提供了理论支持.%Since fruit and vegetable are highly perishable, and have strong timeliness in selling and consuming, the delivery routes of transport vehicles must be planned reasonably. On the path of fruit and vegetable delivery, a transport vehicle may encounter some unusual circumstances and may not arrive at the next distribution site in time. In this case, the vehicle routes of other transport vehicles should be replanned. A mathematical model for vehicle route replanning with time windows for fruit and vegetable delivery was established, and an improved ant colony algorithm was used to resolve the model. Simulation experiment results showed that the new dispatching routing of fruit and vegetable could be optimized efficiently by using the proposed model and adopted algorithm. This research could provide theoretical support for enterprises which hoped to decrease rot loss of fruit and vegetable, increase sales income and control operating cost effectively.
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Jingling Zhang
2012-01-01
Full Text Available The multiobjective vehicle routing problem considering customer satisfaction (MVRPCS involves the distribution of orders from several depots to a set of customers over a time window. This paper presents a self-adaptive grid multi-objective quantum evolutionary algorithm (MOQEA for the MVRPCS, which takes into account customer satisfaction as well as travel costs. The degree of customer satisfaction is represented by proposing an improved fuzzy due-time window, and the optimization problem is modeled as a mixed integer linear program. In the MOQEA, nondominated solution set is constructed by the Challenge Cup rules. Moreover, an adaptive grid is designed to achieve the diversity of solution sets; that is, the number of grids in each generation is not fixed but is automatically adjusted based on the distribution of the current generation of nondominated solution set. In the study, the MOQEA is evaluated by applying it to classical benchmark problems. Results of numerical simulation and comparison show that the established model is valid and the MOQEA is effective for MVRPCS.
Polynomial Size Formulations for the Distance and Capacity Constrained Vehicle Routing Problem
Kara, Imdat; Derya, Tusan
2011-09-01
The Distance and Capacity Constrained Vehicle Routing Problem (DCVRP) is an extension of the well known Traveling Salesman Problem (TSP). DCVRP arises in distribution and logistics problems. It would be beneficial to construct new formulations, which is the main motivation and contribution of this paper. We focused on two indexed integer programming formulations for DCVRP. One node based and one arc (flow) based formulation for DCVRP are presented. Both formulations have O(n2) binary variables and O(n2) constraints, i.e., the number of the decision variables and constraints grows with a polynomial function of the nodes of the underlying graph. It is shown that proposed arc based formulation produces better lower bound than the existing one (this refers to the Water's formulation in the paper). Finally, various problems from literature are solved with the node based and arc based formulations by using CPLEX 8.0. Preliminary computational analysis shows that, arc based formulation outperforms the node based formulation in terms of linear programming relaxation.
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Behrouz Afshar-Nadjafi
2017-01-01
Full Text Available In this paper, we consider the time-dependent multi-depot vehicle routing problem. The objective is to minimize the total heterogeneous fleet cost assuming that the travel time between locations depends on the departure time. Also, hard time window constraints for the customers and limitation on maximum number of the vehicles in depots must be satisfied. The problem is formulated as a mixed integer programming model. A constructive heuristic procedure is proposed for the problem. Also, the efficiency of the proposed algorithm is evaluated on 180 test problems. The obtained computational results indicate that the procedure is capable to obtain a satisfying solution.
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Xiaobing Gan
2012-01-01
Full Text Available This paper considers two additional factors of the widely researched vehicle routing problem with time windows (VRPTW. The two factors, which are very common characteristics in realworld, are uncertain number of vehicles and simultaneous delivery and pick-up service. Using minimization of the total transport costs as the objective of the extension VRPTW, a mathematic model is constructed. To solve the problem, an efficient multiswarm cooperative particle swarm optimization (MCPSO algorithm is applied. And a new encoding method is proposed for the extension VRPTW. Finally, comparing with genetic algorithm (GA and particle swarm optimization (PSO algorithm, the MCPSO algorithm performs best for solving this problem.
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Ming Zhang
2016-10-01
Full Text Available Route planning is a key technology for an unmanned aerial vehicle (UAV to fly reliably and safely in the presence of a threat environment. Existing route planning methods are mainly based on the simulation scene, whereas approaches based on the virtual globe platform have rarely been reported. In this paper, a new planning space for the virtual globe and the planner is proposed and a common threat model is constructed for threats including a no-fly zone, hazardous weather, radar coverage area, missile killing zone and dynamic threats. Additionally, an improved ant colony optimization (ACO algorithm is developed to enhance route planning efficiency and terrain masking ability. Our route planning methods are optimized on the virtual globe platform for practicability. A route planning system and six types of planners were developed and implemented on the virtual globe platform. Finally, our evaluation results demonstrate that our optimum planner has better performance in terms of fuel consumption, terrain masking, and risk avoidance. Experiments also demonstrate that the method and system described in this paper can be used to perform global route planning and mission operations.
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Jianhua Ma
2013-01-01
Full Text Available The objective of vehicle routing problem is usually to minimize the total traveling distance or cost. But in practice, there are a lot of problems needed to minimize the fastest completion time. The milk-run vehicle routing problem (MRVRP is widely used in milk-run distribution. The mutation ACO is given to solve MRVRP with fastest completion time in this paper. The milk-run VRP with fastest completion time is introduced first, and then the customer division method based on dynamic optimization and split algorithm is given to transform this problem into finding the optimal customer order. At last the mutation ACO is given and the numerical examples verify the effectiveness of the algorithm.
Ma, Yanfang; Xu, Jiuping
2015-06-01
This article puts forward a cloud theory-based particle swarm optimization (CTPSO) algorithm for solving a variant of the vehicle routing problem, namely a multiple decision maker vehicle routing problem with fuzzy random time windows (MDVRPFRTW). A new mathematical model is developed for the proposed problem in which fuzzy random theory is used to describe the time windows and bi-level programming is applied to describe the relationship between the multiple decision makers. To solve the problem, a cloud theory-based particle swarm optimization (CTPSO) is proposed. More specifically, this approach makes improvements in initialization, inertia weight and particle updates to overcome the shortcomings of the basic particle swarm optimization (PSO). Parameter tests and results analysis are presented to highlight the performance of the optimization method, and comparison of the algorithm with the basic PSO and the genetic algorithm demonstrates its efficiency.
基于车辆任务可靠性的协同车辆路径问题%Collaborative vehicle route problem based on vehicle task reliability
Institute of Scientific and Technical Information of China (English)
孙博; 魏明; 姚娟
2013-01-01
研究一类属于不同公司的配送中心共享车队、仓储等资源为客户协同配送货物的协同车辆路径问题,将之视为“部分客户被一车辆访问”的集合划分问题.考虑车辆容量、车辆行驶最大里程、车辆配送任务的可靠性概率、时间窗等约束条件,建立以车辆配送总费用最小为目标的混合整数规划模型,并设计了求解该问题的遗传算法求解该问题.最后,通过一个算例验证了模型的正确性和合理性.%This paper studied the collaborative vehicle routing problem (CVRP),which depots belonged to different companies served their customers by sharing motorcades and warehousing to optimize total cost of collaborative transport,treated as a "some customers are serviced by a vehicle" set-partitioning problem.Considerihg some constraints such as vehicle' s capacity,maximum mileages of different vehicles,reliability of vehicle' s delivery and time window etc.,it built a mixed integer programming model for collaborative vehicles routing to optimize total cost of dispatching.The model was solved by genetic algorithm (GA).Finally,an example shows the correctness and effectiveness of the model.
Selçuk K. İşleyen; Ö. Faruk Baykoç
2008-01-01
We define a special case for the vehicle routing problem with stochastic demands (SC-VRPSD) where customer demands are normally distributed. We propose a new linear model for computing the expected length of a tour in SC-VRPSD. The proposed model is based on the integration of the “Traveling Salesman Problem” (TSP) and the Assignment Problem. For large-scale problems, we also use an Iterated Local Search (ILS) algorithm in order to reach an effective solution.
Performance Evaluation of Ad Hoc Routing Protocols in a Swarm of Autonomous Unmanned Aerial Vehicles
2007-03-01
demand Distance Vector Routing ( AODV ) Like DSDV, the AODV protocol uses sequence numbers to prevent routing loops. Originally presented by Perkins...DSR, though as with most demand-driven routing protocols , path discovery causes some latency at the start of each data session. Unlike DSR, AODV ...research in mobile, ad hoc routing protocols . Broch, et al. performed a simulation comparison of the DSDV, DSR, AODV and Temporally-Ordered
Meysam Mousavi, S.; Tavakkoli-Moghaddam, Reza; Jolai, Fariborz
2013-10-01
This article considers the design of cross-docking systems under uncertainty in a model that consists of two phases: (1) a strategic-based decision-making process for selecting the location of cross-docks to operate, and (2) an operational-based decision-making process for vehicle routing scheduling with multiple cross-docks. This logistic system contains three echelons, namely suppliers, cross-docks and retailers, in an uncertain environment. In the first phase, a new multi-period cross-dock location model is introduced to determine the minimum number of cross-docks among a set of location sites so that each retailer demand should be met. Then, in the second phase, a new vehicle routing scheduling model with multiple cross-docks is formulated in which each vehicle is able to pickup from or deliver to more than one supplier or retailer, and the pickup and delivery routes start and end at the corresponding cross-dock. This article is the first attempt to introduce an integrated model for cross-docking systems design under a fuzzy environment. To solve the presented two-phase mixed-integer programming (MIP) model, a new fuzzy mathematical programming-based possibilistic approach is used. Furthermore, experimental tests are carried out to demonstrate the effectiveness of the presented model. The computational results reveal the applicability and suitability of the developed fuzzy possibilistic two-phase model in a variety of problems in the domain of cross-docking systems.
Directory of Open Access Journals (Sweden)
Peiqing Li
2015-01-01
Full Text Available Fresh fruits and vegetables, perishable by nature, are subject to additional deterioration and bruising in the distribution process due to vibration and shock caused by road irregularities. A nonlinear mathematical model was developed that considered not only the vehicle routing problem with time windows but also the effect of road irregularities on the bruising of fresh fruits and vegetables. The main objective of this work was to obtain the optimal distribution routes for fresh fruits and vegetables considering different road classes with the least amount of logistics costs. An improved genetic algorithm was used to solve the problem. A fruit delivery route among the 13 cities in Jiangsu Province was used as a real analysis case. The simulation results showed that the vehicle routing problem with time windows, considering road irregularities and different classes of toll roads, can significantly influence total delivery costs compared with traditional VRP models. The comparison between four models to predict the total cost and actual total cost in distribution showed that the improved genetic algorithm is superior to the Group-based pattern, CW pattern, and O-X type cross pattern.
Directory of Open Access Journals (Sweden)
Bruno Santos Goulart
2014-09-01
Full Text Available An efficient combustion depends on many factors, such as injection, turbulence and ignition characteristics. With the improvement of internal combustion engines the turbulence intensity and internal pressure have risen, demanding more efficient and powerful ignition systems. In direct injection engines, the stratified charge resultant from the wall/air-guided or spray-guided system requires even more energy. The Paschen’s law shows that spark plug gap and mixture density are proportional to the dielectric rupture voltage. It is known that larger spark gaps promote higher efficiency in the internal combustion engines, since the mixture reaction rate rises proportionally. However, the ignition system must be adequate to the imposed gap, not only on energy, but also on voltage and spark duration. For the reported study in this work two test benches were built: a standard inductive ignition system and a capacitive discharge high energy ignition system, with variable voltage and capacitance. The influence of the important parameters energy and ignition voltage on the spark duration, as well as the electrode gap and shape were analyzed. It was also investigated the utilization of a coil with lower resistance and inductance values, as well as spark plugs with and without internal resistances.
Directory of Open Access Journals (Sweden)
Hossein Yousefi
2017-06-01
Full Text Available A vehicle routing problem with time windows (VRPTW is an important problem with many real applications in a transportation problem. The optimum set of routes with the minimum distance and vehicles used is determined to deliver goods from a central depot, using a vehicle with capacity constraint. In the real cases, there are other objective functions that should be considered. This paper considers not only the minimum distance and the number of vehicles used as the objective function, the customer’s satisfaction with the priority of customers is also considered. Additionally, it presents a new model for a bi-objective VRPTW solved by a revised multi-choice goal programming approach, in which the decision maker determines optimistic aspiration levels for each objective function. Two meta-heuristic methods, namely simulated annealing (SA and genetic algorithm (GA, are proposed to solve large-sized problems. Moreover, the experimental design is used to tune the parameters of the proposed algorithms. The presented model is verified by a real-world case study and a number of test problems. The computational results verify the efficiency of the proposed SA and GA.
Directory of Open Access Journals (Sweden)
Yu Lin
2015-01-01
Full Text Available High frequency and small lot size are characteristics of milk runs and are often used to implement the just-in-time (JIT strategy in logistical systems. The common frequency problem, which simultaneously involves planning of the route and frequency, has been extensively researched in milk run systems. In addition, vehicle type choice in the milk run system also has a significant influence on the operating cost. Therefore, in this paper, we simultaneously consider vehicle routing planning, frequency planning, and vehicle type choice in order to optimize the sum of the cost of transportation, inventory, and dispatch. To this end, we develop a mathematical model to describe the common frequency problem with vehicle type choice. Since the problem is NP hard, we develop a two-phase heuristic algorithm to solve the model. More specifically, an initial satisfactory solution is first generated through a greedy heuristic algorithm to maximize the ratio of the superior arc frequency to the inferior arc frequency. Following this, a tabu search (TS with limited search scope is used to improve the initial satisfactory solution. Numerical examples with different sizes establish the efficacy of our model and our proposed algorithm.
带有随机需求的车辆路径选择问题算法研究%A Solution Algorithm for Vehicle Routing Problem with Stochastic Demands
Institute of Scientific and Technical Information of China (English)
吕萌; 朱金福; 王瑞凯
2012-01-01
This paper proposes a new solution algorithm to the Vehicle Routing Problem with Stochastic Demands ( VRPSD). The theoretical basis of this algorithm is to transform a given VRPSD problem into solving a limited set of Capacitated Vehicle Routing Problem (CVRP) instances, and then the VRPSD problem can be solved by solving the corresponding CVRP problem. This paper recommends using the concept of safety stock to enhance the reliability of the solutions to above problem. This study also uses Monte Carlo simulation to estimate the reliability each possible path under different level of safety stock. Finally, an example is used to demonstrate the reliability and generality of the described algorithm.%为带有随机需求的车辆路径问题( VRPSD)提供一个具有通用性的算法,将一个VRPSD问题转化成带有运力限制的车辆路径问题(CVRP)的有限集,通过解CVRP问题来解决VRPSD问题.为提高解的可靠性引入了安全库存的概念,并运用了蒙特卡罗仿真方法,得到了在不同安全库存水平下每条路径的可靠性.用实例检验所述方法的可靠性和通用性.
Institute of Scientific and Technical Information of China (English)
刘万峰; 李霞
2015-01-01
对于容量约束的车辆路径问题( capacitated vehicle routing problem, CVRP)以及容量和最大行驶距离约束的车辆问题( capacitated and distance constrained vehicle routing problem, CDVRP),邻域解的评估包含了适应值计算及合法性评估.设计一种可变长编码的可行解表示,提出用于CVRP/CDVRP问题的邻域解合法性快速评估策略.该策略针对交换、插入、2-opt和2-opt∗四种常用的局部搜索算子,通过引入前载重、后载重、前向距离和后向距离的概念,实现了邻域解合法性的快速评估.将改进后的局部搜索算子与迭代局部搜索( iterated local search, ILS)算法相结合,提出用于车辆路径问题的快速多邻域迭代局部搜索( fast multi-neighborhood ILS, FMNILS)算法.该快速评估策略将评估一个邻域解的时间复杂度由O( N)降至O(1),算法仿真结果表明, FMNILS算法运算能力的提高大致与配送路线所服务的客户数成正比；对客户数介于200~500的容量/最大距离约束VRP问题,该算法能在短时间内获得较满意解,平均求解精度1．2%以内,平均耗时约96 s,仅为对比算法的6%或更少.%For capacitated vehicle routing problems without/with maximum traveling distance constraint ( CVRP/CDVRP) , the evaluation of neighborhood solutions involves fitness calculation and feasibility assessment. This paper proposes a fast feasibility assessment strategy in which variable length coding is used to represent feasible solutions of vehicle routing problem. We introduce the concepts of pre-load, post-load, pre-distance and post-distance to obtain fast feasibility assessments for neighborhood solutions achieved by four widely used local search operations ( insert, exchange, 2-opt, and 2-opt∗). By combining the improved local search operations and iterated local search (ILS), we propose a fast multi-neighborhood iterated local search ( FMNILS) for CVRP. The feasibility assessment strategy can reduce
Hemmelmayr, Vera C; Cordeau, Jean-François; Crainic, Teodor Gabriel
2012-12-01
In this paper, we propose an adaptive large neighborhood search heuristic for the Two-Echelon Vehicle Routing Problem (2E-VRP) and the Location Routing Problem (LRP). The 2E-VRP arises in two-level transportation systems such as those encountered in the context of city logistics. In such systems, freight arrives at a major terminal and is shipped through intermediate satellite facilities to the final customers. The LRP can be seen as a special case of the 2E-VRP in which vehicle routing is performed only at the second level. We have developed new neighborhood search operators by exploiting the structure of the two problem classes considered and have also adapted existing operators from the literature. The operators are used in a hierarchical scheme reflecting the multi-level nature of the problem. Computational experiments conducted on several sets of instances from the literature show that our algorithm outperforms existing solution methods for the 2E-VRP and achieves excellent results on the LRP.
Hemmelmayr, Vera C.; Cordeau, Jean-François; Crainic, Teodor Gabriel
2012-01-01
In this paper, we propose an adaptive large neighborhood search heuristic for the Two-Echelon Vehicle Routing Problem (2E-VRP) and the Location Routing Problem (LRP). The 2E-VRP arises in two-level transportation systems such as those encountered in the context of city logistics. In such systems, freight arrives at a major terminal and is shipped through intermediate satellite facilities to the final customers. The LRP can be seen as a special case of the 2E-VRP in which vehicle routing is performed only at the second level. We have developed new neighborhood search operators by exploiting the structure of the two problem classes considered and have also adapted existing operators from the literature. The operators are used in a hierarchical scheme reflecting the multi-level nature of the problem. Computational experiments conducted on several sets of instances from the literature show that our algorithm outperforms existing solution methods for the 2E-VRP and achieves excellent results on the LRP. PMID:23483764
Mobility Prediction Progressive Routing (MP2R), a Cross-Layer Design for Inter-Vehicle Communication
Tang, Suhua; Kadowaki, Naoto; Obana, Sadao
In this paper we analyze the characteristics of vehicle mobility and propose a novel Mobility Prediction Progressive Routing (MP2R) protocol for Inter-Vehicle Communication (IVC) that is based on crosslayer design. MP2R utilizes the additional gain provided by the directional antennas to improve link quality and connectivity; interference is reduced by the directional transmission. Each node learns its own position and speed and that of other nodes, and performs position prediction. (i) With the predicted progress and link quality, the forwarding decision of a packet is locally made, just before the packet is actually transmitted. In addition the load at the forwarder is considered in order to avoid congestion. (ii) The predicted geographic direction is used to control the beam of the directional antenna. The proposed MP2R protocol is especially suitable for forwarding burst traffic in highly mobile environments. Simulation results show that MP2R effectively reduces Packet Error Ratio (PER) compared with both topology-based routing (AODV [1], FSR [2]) and normal progressive routing (NADV [18]) in the IVC scenarios.
A Novel Discrete Differential Evolution Algorithm for the Vehicle Routing Problem in B2C E-Commerce
Xia, Chao; Sheng, Ying; Jiang, Zhong-Zhong; Tan, Chunqiao; Huang, Min; He, Yuanjian
2015-12-01
In this paper, a novel discrete differential evolution (DDE) algorithm is proposed to solve the vehicle routing problems (VRP) in B2C e-commerce, in which VRP is modeled by the incomplete graph based on the actual urban road system. First, a variant of classical VRP is described and a mathematical programming model for the variant is given. Second, the DDE is presented, where individuals are represented as the sequential encoding scheme, and a novel reparation operator is employed to repair the infeasible solutions. Furthermore, a FLOYD operator for dealing with the shortest route is embedded in the proposed DDE. Finally, an extensive computational study is carried out in comparison with the predatory search algorithm and genetic algorithm, and the results show that the proposed DDE is an effective algorithm for VRP in B2C e-commerce.
The research on multi-depot and multi-vehicle-type related vehicle routing problem%类电磁机制算法的应用研究
Institute of Scientific and Technical Information of China (English)
段熙鹏; 蔡延光; 汤雅连
2012-01-01
The iwproved electromagnetism-like mechanism algorithm （EMA） was introduced, and this algorithm was applied to solve multi-depot and multi-vehicle-type related vehicle routing problem. Local search can improve the ability of fine search in the local area, moreover, mobile coefficient can improve the convergence rate. The results show that improved EMA is feasible and flexible to solve this type of RVRP and its better than traditional EMA.%摘要：针对多车场多车型的关联运输调度问题（Multi-depot and Multi—vehicle—type Related Vehi—cle Routing Problem），对传统的类电磁机制算法进行改进，局部搜索可以提高算法在局部区域精细搜索的能力，并引入了移动系数来提高算法的收敛速度。实验结果证明，改进的算法有效地解决了此类问题且优于传统类电磁机制算法。
Directory of Open Access Journals (Sweden)
2009-03-01
Full Text Available We define a special case for the vehicle routing problem with stochastic demands (SC-VRPSD where customer demands are normally distributed. We propose a new linear model for computing the expected length of a tour in SC-VRPSD. The proposed model is based on the integration of the “Traveling Salesman Problem” (TSP and the Assignment Problem. For large-scale problems, we also use an Iterated Local Search (ILS algorithm in order to reach an effective solution.
Directory of Open Access Journals (Sweden)
Jhon Jairo Santa Chávez
2016-01-01
Full Text Available This paper presents a multiobjective ant colony algorithm for the Multi-Depot Vehicle Routing Problem with Backhauls (MDVRPB where three objectives of traveled distance, traveling times and total consumption of energy are minimized. An ant colony algorithm is proposed to solve the MDVRPB. The solution scheme allows one to find a set of ordered solutions in Pareto fronts by considering the concept of dominance. The effectiveness of the proposed approach is examined by considering a set of instances adapted from the literature. The computational results show high quality results within short computing times.
Exactly solving the Split Pickup and Split Delivery Vehicle Routing Problem on a bike-sharing system
Casazza, Marco
2016-01-01
We propose an exact methodology to solve the Split Pickup and Split Delivery Vehicle Routing Problem arising in bike-sharing systems: a bike-sharing system is a public service in which bicycles are stored in rack stations and made available for shared use to individuals on a short term basis. However, during peak hours, flows along particular direction are registered, leading to high risk of empty racks in departure stations, and full racks at destination. One of the solutions chosen by many ...
Directory of Open Access Journals (Sweden)
Suphan Sodsoon
2014-06-01
Full Text Available This study aims to solve a Vehicle Routing Problem with Time Windows and Speed Limits (VRPTWSL, which has received considerable attention in recent years. The vehicle routing problem with time windows is an extension of the well-known Vehicle Routing Problem (VRP and involves a fleet of vehicles set of from a depot to serve a number of customers at different geographic locations with various demands within specific time and speed limits before returning to the depot eventually. To solve the problem, an efficient Saving Method-Max Min Ant System (Saving-MMAS with Local Search algorithm is applied. Using minimization of the total transportation costs as the objective of the extension VRPTWSL, a mathematic model is constructed. Finally, the Saving-MMAS algorithms indicated the good quality of the method in this problem.
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Julia Rieck
2013-05-01
Full Text Available In reverse logistics networks, products (e.g., bottles or containers have to be transported from a depot to customer locations and, after use, from customer locations back to the depot. In order to operate economically beneficial, companies prefer a simultaneous delivery and pick-up service. The resulting Vehicle Routing Problem with Simultaneous Delivery and Pick-up (VRPSDP is an operational problem, which has to be solved daily by many companies. We present two mixed-integer linear model formulations for the VRPSDP, namely a vehicle-flow and a commodity-flow model. In order to strengthen the models, domain-reducing preprocessing techniques, and effective cutting planes are outlined. Symmetric benchmark instances known from the literature as well as new asymmetric instances derived from real-world problems are solved to optimality using CPLEX 12.1.
Energy Technology Data Exchange (ETDEWEB)
Machado, Guilherme Bastos, Cordeiro de Melo, Tadeu Cavalcante; Leao, Raphael Riemke de Campos Cesar; Iaccarino, Fernando Aniello; Figueiredo Moreira, Marcia
2007-07-01
The Brazilian CNG light-duty vehicle fleet has currently reached more than 1,300,000 units. This growth increased in the late 1990's, when CNG was approved for use in passenger cars. In 2001, the IBAMA (Brazilian Institute for Environment and Natural Renewable Resources), concerned with this uncontrolled growth, published CONAMA (National Environmental Council, controlled by IBAMA) resolution 291, which establishes rules for CNG conversion kit environmental certification.This paper discusses the technological challenges for CNG-converted vehicles to comply with PROCONVE (Brazilian Program for Automotive Air Pollution Control) emission limits. In the 1980's, because of the oil crisis, Natural Gas (NG) emerged as a fuel with great potential to replace Diesel in heavy-duty vehicles. Some experiences were conducted for partial conversions from Diesel to NG (Diesel-gas). Other experiences using NG Otto Cycle buses were conducted in some cities, but have not expanded. Another technological route called 'Ottolization' (Diesel to Otto cycle convertion) appeared recently. Population increase and the great growth in vehicle fleet promote a constant concern with automotive emissions. More restrictive emission limits, high international oil prices, and the strategic interest in replacing Diesel imports, altogether form an interesting scenario for CNG propagation to public transportation in the main Brazilian metropolises.
Directory of Open Access Journals (Sweden)
Zheng Wang
2016-01-01
Full Text Available This paper presents a saving-based heuristic for the vehicle routing problem with time windows and stochastic travel times (VRPTWSTT. One of the basic ideas of the heuristic is to advance the latest service start time of each customer by a certain period of time. In this way, the reserved time can be used to cope with unexpected travel time delay when necessary. Another important idea is to transform the VRPTWSTT to a set of vehicle routing problems with time windows (VRPTW, each of which is defined by a given percentage used to calculate the reserved time for customers. Based on the above two key ideas, a three-stage heuristic that includes the “problem transformation” stage, the “solution construction” stage, and the “solution improvement” stage is developed. After the problem transformation in the first stage, the work of the next two stages is to first construct an initial solution for each transformed VRPTW by improving the idea of the classical Clarke-Wright heuristic and then further improve the solution. Finally, a number of numerical experiments are conducted to evaluate the efficiency of the described methodology under different uncertainty levels.
Research for Routing Planning of Vehicle Transportation%车辆运输路径规划问题研究
Institute of Scientific and Technical Information of China (English)
于锐; 曹介南; 朱培栋
2011-01-01
In order to better resolve the vehicle routing planning problem of armed police transportation, and increase the rapidity of military operations,the open vehicle routing problem(OVRP) model is constituted on the base of actual request of armed police transportation, which adds a good many limited conditions, such as vehicle capacity and time window restraint etc. At the same time, the basic principle of the saving algorithm is described,and this question was resolved using an improved saving algorithm. The more satisfactory answer is got through the verification of actual case. Not only can the time limit be met,but also the transport distance and transport charge are reduced. It is shown that this arithmetic is concise,comprehensible and operable.%为了更好地解决武警车辆运输路径规划问题,提高部队行动的迅速性,在考虑武警车辆运输实际需求的基础上,文中建立了开放式车辆路径模型,增加了诸多约束条件.例如车辆容量限制、时间窗限制等等.同时,论述了节约算法的基本原理,并采用设计改进的节约算法对开放式车辆路径问题进行了求解.通过实际案例的验证,采用改进的节约算法能够得到较满意的解,既能够满足时间限制,又能够节约运输里程和费用.结果表明,此种算法简明、易于理解,且可操作性强.
Procedures for Vehicle Routing Problems with An Application to Milk Assembly in New York
1982-01-01
This paper discusses improved procedures for applying heuristic methods to well-known transportation and routing algorithms for solving a milk assembly problem. Miles traveled to assemble milk are reduced by up to 20 percent in a detailed case study in New York.
Logistics of emergency response vehicles : facility location, routing, and shift scheduling
P.L. van den Berg (Pieter)
2016-01-01
textabstractThis thesis discusses different aspects of the logistics of emergency response vehicles. In most parts, we consider providers of ambulance care in the Netherlands. However, also firefighters and air ambulance providers in both Canada and Norway are considered. Even though significant dif
Chixiao, Chen; Jixuan, Xiang; Huabin, Chen; Jun, Xu; Fan, Ye; Ning, Li; Junyan, Ren
2015-05-01
Asynchronous successive approximation register (SAR) analog-to-digital converters (ADC) feature high energy efficiency but medium performance. From the point of view of speed, the key bottleneck is the unit capacitor size. In this paper, a small size three-dimensional (3-D) metal—oxide—metal (MOM) capacitor is proposed. The unit capacitor has a capacitance of 1-fF. It shapes as an umbrella, which is designed for fast settling consideration. A comparison among the proposed capacitor with other 3-D MOM capacitors is also given in the paper. To demonstrate the effectiveness of the MOM capacitor, a 6-b capacitive DAC is implemented in TSMC 1P9M 65 nm LP CMOS technology. The DAC consumes a power dissipation of 0.16 mW at the rate of 100 MS/s, excluding a source-follower based output buffer. Static measurement result shows that INL is less than ±1 LSB and DNL is less than ±0.5 LSB. In addition, a 100 MS/s 9-bit SAR ADC with the proposed 3-D capacitor is simulated.
Vehicle Routing Optimization Based on Improved PSO%基于改进PSO的汽车路径优化
Institute of Scientific and Technical Information of China (English)
黄小燕; 文展; 付克昌; 朱明
2009-01-01
车辆路径问题(Vehicle Routing Problem,VRP)是物流中的重要环节,主要研究物流配送中车辆线路优化以降低运输成本.本文利用粒子群优化算法求解VRP,为了提高求解效率,通过构造自学习算子、微粒的重新编码及运算规则的重新定义,使PSO算法能够处理离散问题,把微粒群算法应用于VRP问题的求解中,通过仿真证明了提出方法求解VRP问题的有效性和优越性.
Directory of Open Access Journals (Sweden)
Michael Polacek
2008-12-01
Full Text Available In this paper we propose two cooperation schemes to compose new parallel variants of the Variable Neighborhood Search (VNS. On the one hand, a coarse-grained cooperation scheme is introduced which is well suited for being enhanced with a solution warehouse to store and manage the so far best found solutions and a self-adapting mechanism for the most important search parameters. This makes an a priori parameter tuning obsolete. On the other hand, a fine-grained scheme was designed to reproduce the successful properties of the sequential VNS. In combination with the use of parallel exploration threads all of the best solutions and 11 out of 20 new best solutions for the Multi Depot Vehicle Routing Problem with Time Windows were found.
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Babak Farhang Moghadam
2010-07-01
Full Text Available During the past few years, there have tremendous efforts on improving the cost of logistics using varieties of Vehicle Routing Problem (VRP models. In fact, the recent rise on fuel prices has motivated many to reduce the cost of transportation associated with their business through an improved implementation of VRP systems. We study a specific form of VRP where demand is supposed to be uncertain with unknown distribution. A Particle Swarm Optimization (PSO is proposed to solve the VRP and the results are compared with other existing methods. The proposed approach is also used for real world case study of drug distribution and the preliminary results indicate that the method could reduce the unmet demand significantly.
物流配送车辆路径优化问题的仿真研究%Vehicle Routing Optimization Problem of Logistics Distribution
Institute of Scientific and Technical Information of China (English)
吴洁明
2011-01-01
Logistics distribution vehicle routing optimization problem is studied to reduce logistics transportation cost. Logistics distribution vehicle routing problem is a typical NP problem, traditional optimization methods have the defects of long searching time, difficult to find the optimal path, and high logistics costs. In order to reduce logistics distribution cost and improve vehicle routing optimization efficiency, a logistics distribution vehicle routing optimization algorithm on ant colony algorithm is put forward. Firstly, the logistics distribution vehicle routing problems are analyzed, a corresponding mathematical model established, and then the ant colony algorithm is used to sovle the mathematical model for the vehicle routing problem. The algorithm is verified by experiment with instances, and the experimental results show that the ant colony algorithm can improve optimal effect, the optimal solution of vehicel route is shorter than other algorithms, and the logistics cost is reduced. It is an effective algorithm to sovle the logistics distribution vehicle routing problem.%研究物流配送车辆路径优化问题,由于物流行业要求货物及时配送,又要降低物流运输成本.物流配送车辆路径选择是重点解决的问题,传统优化方法搜索时间长,难以找到最优路径,造成物流配送成本高.为了降低物流配送成本,提高车辆路径优化效率,提出一种蚁群算法的物流配送车辆路径优化算法.首先对物流配送车辆路径问题进行分析,然后建立相应的数学模型,最后采用蚁群算法对车辆路径问题的数学模型进行求解.通过具体实例对算法进行实验,实验结果表明,蚁群算法提高寻优效果,找到的物流配送车辆路径的最优解短于其它算法,降低物流配送成本,并为物流配送车辆路径选择提供了一种有效算法.
Zhang, Jisheng; Jia, Limin; Niu, Shuyun; Zhang, Fan; Tong, Lu; Zhou, Xuesong
2015-06-12
It is essential for transportation management centers to equip and manage a network of fixed and mobile sensors in order to quickly detect traffic incidents and further monitor the related impact areas, especially for high-impact accidents with dramatic traffic congestion propagation. As emerging small Unmanned Aerial Vehicles (UAVs) start to have a more flexible regulation environment, it is critically important to fully explore the potential for of using UAVs for monitoring recurring and non-recurring traffic conditions and special events on transportation networks. This paper presents a space-time network- based modeling framework for integrated fixed and mobile sensor networks, in order to provide a rapid and systematic road traffic monitoring mechanism. By constructing a discretized space-time network to characterize not only the speed for UAVs but also the time-sensitive impact areas of traffic congestion, we formulate the problem as a linear integer programming model to minimize the detection delay cost and operational cost, subject to feasible flying route constraints. A Lagrangian relaxation solution framework is developed to decompose the original complex problem into a series of computationally efficient time-dependent and least cost path finding sub-problems. Several examples are used to demonstrate the results of proposed models in UAVs' route planning for small and medium-scale networks.
Directory of Open Access Journals (Sweden)
Jisheng Zhang
2015-06-01
Full Text Available It is essential for transportation management centers to equip and manage a network of fixed and mobile sensors in order to quickly detect traffic incidents and further monitor the related impact areas, especially for high-impact accidents with dramatic traffic congestion propagation. As emerging small Unmanned Aerial Vehicles (UAVs start to have a more flexible regulation environment, it is critically important to fully explore the potential for of using UAVs for monitoring recurring and non-recurring traffic conditions and special events on transportation networks. This paper presents a space-time network- based modeling framework for integrated fixed and mobile sensor networks, in order to provide a rapid and systematic road traffic monitoring mechanism. By constructing a discretized space-time network to characterize not only the speed for UAVs but also the time-sensitive impact areas of traffic congestion, we formulate the problem as a linear integer programming model to minimize the detection delay cost and operational cost, subject to feasible flying route constraints. A Lagrangian relaxation solution framework is developed to decompose the original complex problem into a series of computationally efficient time-dependent and least cost path finding sub-problems. Several examples are used to demonstrate the results of proposed models in UAVs’ route planning for small and medium-scale networks.
Zhang, Jisheng; Jia, Limin; Niu, Shuyun; Zhang, Fan; Tong, Lu; Zhou, Xuesong
2015-01-01
It is essential for transportation management centers to equip and manage a network of fixed and mobile sensors in order to quickly detect traffic incidents and further monitor the related impact areas, especially for high-impact accidents with dramatic traffic congestion propagation. As emerging small Unmanned Aerial Vehicles (UAVs) start to have a more flexible regulation environment, it is critically important to fully explore the potential for of using UAVs for monitoring recurring and non-recurring traffic conditions and special events on transportation networks. This paper presents a space-time network- based modeling framework for integrated fixed and mobile sensor networks, in order to provide a rapid and systematic road traffic monitoring mechanism. By constructing a discretized space-time network to characterize not only the speed for UAVs but also the time-sensitive impact areas of traffic congestion, we formulate the problem as a linear integer programming model to minimize the detection delay cost and operational cost, subject to feasible flying route constraints. A Lagrangian relaxation solution framework is developed to decompose the original complex problem into a series of computationally efficient time-dependent and least cost path finding sub-problems. Several examples are used to demonstrate the results of proposed models in UAVs’ route planning for small and medium-scale networks. PMID:26076404
A Time-Slotted On-Demand Routing Protocol for Mobile Ad Hoc Unmanned Vehicle Systems
Energy Technology Data Exchange (ETDEWEB)
Hope Forsmann; Robert Hiromoto; John Svoboda
2007-04-01
The popularity of UAVs has increased dramatically because of their successful deployment in military operations, their ability to preserve human life, and the continual improvements in wireless communication that serves to increase their capabilities. We believe the usefulness of UAVs would be dramatically increased if formation flight were added to the list of capabilities. Currently, sustained formation flight with a cluster of UAVs has only been achieved with two nodes by the Multi-UAV Testbed at the Massachusetts Institute of Technology. (Park, 2004) Formation flight is a complex operation requiring the ability to adjust the flight patterns on the fly and correct for wind gusts, terrain, and differences in node equipment. All of which increases the amount of inner node communication. Since one of the problems with MANET communication is network congestion, we believe a first step towards formation flight can be made through improved inner node communication. We have investigated current communication routing protocols and developed an altered hybrid routing protocol in order to provide communication with less network congestion.
Directory of Open Access Journals (Sweden)
Wei Tu
2015-10-01
Full Text Available Vehicle routing optimization (VRO designs the best routes to reduce travel cost, energy consumption, and carbon emission. Due to non-deterministic polynomial-time hard (NP-hard complexity, many VROs involved in real-world applications require too much computing effort. Shortening computing time for VRO is a great challenge for state-of-the-art spatial optimization algorithms. From a spatial-temporal perspective, this paper presents a spatial-temporal Voronoi diagram-based heuristic approach for large-scale vehicle routing problems with time windows (VRPTW. Considering time constraints, a spatial-temporal Voronoi distance is derived from the spatial-temporal Voronoi diagram to find near neighbors in the space-time searching context. A Voronoi distance decay strategy that integrates a time warp operation is proposed to accelerate local search procedures. A spatial-temporal feature-guided search is developed to improve unpromising micro route structures. Experiments on VRPTW benchmarks and real-world instances are conducted to verify performance. The results demonstrate that the proposed approach is competitive with state-of-the-art heuristics and achieves high-quality solutions for large-scale instances of VRPTWs in a short time. This novel approach will contribute to spatial decision support community by developing an effective vehicle routing optimization method for large transportation applications in both public and private sectors.
Development and Application of Vehicle Routing Problem%车辆路径问题的发展及其应用
Institute of Scientific and Technical Information of China (English)
卞晨; 赵建东
2016-01-01
As a hotspot in the field of operational research and combinatorial optimization, vehicle routing problem is closely re-lated to real life.As long as the deepening study of vehicle routing problem, various kinds of new types of heuristic algorithm is applied to solve such problems.The vehicle routing problem with various constraint were investigated, analysis and summary in this paper, and the related domestic and foreign research results were reviewed and refined, on this basis, this paper summarizes the research of vehicle routing problem. Based on the current various standard of classification, this paper discusses and analyz-es the classical vehicle routing problem firstly, and summarized the basic methods and modern heuristic algorithm on this basis.%车辆路径问题作为运筹学和组合优化领域的热点问题，与现实生活息息相关。随着对车辆路径问题的不断深入研究，各类新型的启发式算法被运用到解决这类问题之中。文对具有各类约束条件的车辆路径问题进行了调查、分析和总结，并对国内外相关研究成果进行了提炼，在该基础之上，阐述了车辆路径问题的研究综述。基于当前多样的分类标准，讨论并分析了经典车辆路径问题，并在此基础之上综述了求解各类型车辆路径问题的基本方法和现代启发式算法。
时相关车辆路径规划问题的改进A*算法%Improved A* Algorithm for Time - Dependent Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
张翼; 唐国金; 陈磊
2012-01-01
Time -dependent vehicle routing problem (TDVRP) is concerned with vehicle routing optimization in road networks with fluctuant link travel time. Firstly, Time - dependent functions about routing time cost and routing threat cost are introduced. Secondly, a time - dependent heuristic function including routing distance cost, routing time cost and routing threat cost is constructed, and an improved A * algorithm is promoted for TDVRP, where the farther information is included in the algorithm to improve search efficiency. Finally, a road network of vehicle support in troop transportation involving 100 nodes and 190 roads is constructed, and the algorithm is validated by using simulations.%时相关车辆路径问题是研究时变路网环境下的车辆路径优化问题.首先,分别采用阶跃函数和分段连续函数描述不同路径上的跨时段行驶速度和威胁度,将路径时间指标和路径威胁指标表示成时相关函数；其次,为提高搜索效率,对传统A*算法进行改进,在启发函数中增加了最短路径中当前结点的父结点信息,构造了包含里程指标、时间指标和威胁指标的时相关启发函数；最后,构造了包含100个结点、190条路径的车辆机动保障路网模型,通过仿真验证了该算法的有效性.
Kim Oanh, N. T.; Kongpran, J.; Hang, N. T.; Parkpian, P.; Hung, N. T. Q.; Lee, S.-B.; Bae, G.-N.
2013-10-01
Traffic is a major source of air pollution in urban areas of developing countries that leads to high exposure risk of urban dwellers. This study comparatively investigated levels of fine particles (PM2.5), SO2, NO2, and BTEX (benzene, toluene, ethylbenzene and xylenes) at fixed roadsides and on traveling routes in congested urban and less congested suburban areas of Bangkok in 2010. The roadside air quality monitoring was done at two opposite sites across the selected roads. The traffic counting was made simultaneously in these roads and hourly flows of 8 different vehicle types were determined. Roadside PM2.5 levels during dry season were high in both the city center and suburban area, significantly above the wet season, with 65-75% measurements exceeded 24 h Thailand ambient air quality standard of 50 μg m-3. Oppositely, roadside BTEX levels measured in the city center during wet season were higher than dry season and well above those in suburban area. Diurnal variations and the results of SPSS (Statistical Package for the Social Sciences) analysis showed associations between roadside pollutants levels and hourly traffic flows. The differences in pollution levels between 2 monitoring sites across a road were explained by road configurations and prevalent wind directions. On-route pollution levels were measured simultaneously both inside and outside selected vehicles (van, pickup), and on motorcycle. The on-route PM2.5 levels along the urban route were higher during the dry season than wet season. PM2.5 levels inside the vehicles were lower than outside whereas the opposite was observed for BTEX. BTEX were higher on more congested urban sub-routes with lower vehicle speeds. Higher pollution levels suggest a high risk of exposure.
Fuzzy vehicle routing problems based on credibility measure%基于可信性测度的模糊车辆路径问题
Institute of Scientific and Technical Information of China (English)
张力; 杨瑞娜; 汪钱进; 于雪梅
2012-01-01
车辆路径问题（VRP）主要用来寻找有效路径。车辆的起始点都是位于交通中心的仓库，通过车队运输来满足客户对商品的需求。文中介绍不确定条件下的车辆路径问题，即客户的服务时间窗是模糊的。设计一个基于可信性测度的模糊车辆路径模型，并通过模糊模拟和遗传算法的混合智能算法进行求解。最后，结合一个实例说明该模型的应用性和可行性。%Vehicle routing problems aim at finding efficient routes. The starting point of any vehicle lies usually in the depot of traffic centre, for which the customers can be satisfied with the needed commodity transported in vehicle. Analysis is made on the vehicle routing problem in which the travel time window are assumed to be fuzzy variables. A fuzzy optimization model is designed, and fuzzy simulation and genetic algorithm are integrated to obtain a hybrid intelligent algorithm. Finally, an example is given to show the effectiveness of the algorithm.
军事配送式后勤车辆路径问题研究%Research on Military Distribution Logistics Vehicle Routing
Institute of Scientific and Technical Information of China (English)
郝瑞卿; 闫莉
2015-01-01
In order to improve the distribution efficiency of military logistics vehicles and realize the quick response ,a multi-objective dynamic military logistics vehicle routing model with a single time window was established based on the analysis of the characteristics of military logistics vehicle routing . And then a Genetic Ant Colony Hybrid Algorithm of two stages was designed for the model . The simulation results show that the hybrid algorithm overcomes the lower efficiency of the genetic algorithm and the premature convergence of the Ant colony algorithm .It can effectively optimize the dynamic routing of the military logistics distribution vehicles .%为提高军事后勤车辆的配送效率，实现快速响应，文中在分析军事后勤车辆路径问题特点的基础上，建立了单时间窗多目标动态军事后勤车辆路径模型，设计了遗传-蚁群混合算法对模型进行两阶段求解。仿真实验结果表明，该算法解决了遗传算法求解效率低及蚁群算法收敛过早的问题，可有效解决军事后勤车辆动态路径优化问题。
混合算法在车辆路径优化问题中的应用%Application of Hybrid Algorithm in Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
陈印; 徐红梅
2012-01-01
研究车辆路径优化问题,物流配送不仅要求配送及时,而且要求运输成本低,且路径最优.车辆路径优化是解决物流配送效率的关键,传统优化方法寻优效率低,耗时长,难以得到车辆路径最优解,导致物流配送成本过高.为了提高车辆路径寻优效率,降低物流配送成本,提出一种混合算法的车辆路径优化方法.首先建立车辆路径优化数学模型,然后用遗传算法快速找到问题可行解,再将可行解转换成蚁群算法的初始信息素,最后采用蚁群算法从可行解中找到最优车辆路径.仿真结果表明,混合方法提高车辆路径寻优效率,有效地降低物流配送成本.%Research vehicle routing problem. Logistics distribution requires the timely delivery and low transporta-tion cost, and the vehicle routing is the key to solve the logistics distribution problem. The traditional optimization method has the defects of low searching efficiency, time-consuming and high cost. To improve the vehicle route opti-mization efficiency and reduce logistics cost, this paper proposed a hybrid algorithm for vehicle routing optimization method. Firstly, vehicle routing mathematical model was established, and then genetic algorithm was used to find a feasible solution quickly. Then the solution was converted into the initial pheromone of ant colony algorithm. Finally, ant colony algorithm was used to find the optimal solution from the feasible path. The simulation results show that, compared with other optimization methods, the proposed method can improve vehicle routing optimization and reduce the cost of logistics distribution effectively.
Directory of Open Access Journals (Sweden)
Duygu Yilmaz Eroglu
2014-01-01
Full Text Available In this paper, we analyze a real-world OVRP problem for a production company. Considering real-world constrains, we classify our problem as multicapacitated/heterogeneous fleet/open vehicle routing problem with split deliveries and multiproduct (MCHF/OVRP/SDMP which is a novel classification of an OVRP. We have developed a mixed integer programming (MIP model for the problem and generated test problems in different size (10–90 customers considering real-world parameters. Although MIP is able to find optimal solutions of small size (10 customers problems, when the number of customers increases, the problem gets harder to solve, and thus MIP could not find optimal solutions for problems that contain more than 10 customers. Moreover, MIP fails to find any feasible solution of large-scale problems (50–90 customers within time limits (7200 seconds. Therefore, we have developed a genetic algorithm (GA based solution approach for large-scale problems. The experimental results show that the GA based approach reaches successful solutions with 9.66% gap in 392.8 s on average instead of 7200 s for the problems that contain 10–50 customers. For large-scale problems (50–90 customers, GA reaches feasible solutions of problems within time limits. In conclusion, for the real-world applications, GA is preferable rather than MIP to reach feasible solutions in short time periods.
Eroglu, Duygu Yilmaz; Gencosman, Burcu Caglar; Cavdur, Fatih; Ozmutlu, H Cenk
2014-01-01
In this paper, we analyze a real-world OVRP problem for a production company. Considering real-world constrains, we classify our problem as multicapacitated/heterogeneous fleet/open vehicle routing problem with split deliveries and multiproduct (MCHF/OVRP/SDMP) which is a novel classification of an OVRP. We have developed a mixed integer programming (MIP) model for the problem and generated test problems in different size (10-90 customers) considering real-world parameters. Although MIP is able to find optimal solutions of small size (10 customers) problems, when the number of customers increases, the problem gets harder to solve, and thus MIP could not find optimal solutions for problems that contain more than 10 customers. Moreover, MIP fails to find any feasible solution of large-scale problems (50-90 customers) within time limits (7200 seconds). Therefore, we have developed a genetic algorithm (GA) based solution approach for large-scale problems. The experimental results show that the GA based approach reaches successful solutions with 9.66% gap in 392.8 s on average instead of 7200 s for the problems that contain 10-50 customers. For large-scale problems (50-90 customers), GA reaches feasible solutions of problems within time limits. In conclusion, for the real-world applications, GA is preferable rather than MIP to reach feasible solutions in short time periods.
Routing and scheduling problems
DEFF Research Database (Denmark)
Reinhardt, Line Blander
be that the objects routed have an availability time window and a delivery time window or that locations on the path have a service time window. When routing moving transportation objects such as vehicles and vessels schedules are made in connection with the routing. Such schedules represent the time for the presence...... to a destination on a predefined network, the routing and scheduling of vessels in a liner shipping network given a demand forecast to be covered, the routing of manpower and vehicles transporting disabled passengers in an airport and the vehicle routing with time windows where one version studied includes edge...... of a connection between two locations. This could be an urban bus schedule where busses are routed and this routing creates a bus schedule which the passengers between locations use. In this thesis various routing and scheduling problems will be presented. The topics covered will be routing from an origin...
基于禁忌搜索算法的线路规划方案求解%Optimization of open vehicle routing algorithm based on Tabu search
Institute of Scientific and Technical Information of China (English)
廖大强; 邬依林; 印鉴
2015-01-01
针对物流部门中出现的时间窗和车辆限制的开放性车辆线路问题（open vehicle routing problem with time window and vehicle limits，m-OVRPTW），提出基于禁忌搜索算法的线路规划方案。对问题进行数学建模；通过设计4种邻域变化规则、设定多个禁忌长度来改进局部搜索，快速得到高质量近似解，解决m-OVRPTW问题；通过反复选取车辆数量，解决OVRPTW问题。用56组Solomon基准测试数据（VRPTW benchmark problem）进行测试，测试结果表明，将禁忌搜索算法应用在开放性车辆线路问题中取得了较好成果，其在最小车辆数量、最小车辆行程、平均车辆总行程等方面的表现都优于其它算法。%Time window for the logistics sector in open vehicles and restrictions on car lines (Open Vehicle Routing Problem With Time Window and Vehicle Limits,referred to as m-OVRPTW),the proposed routing scheme based on tabu search algorithms. Mathematical modeling issues first;then through four neighborhoods changed rules,setting more taboos-length to improve local search,fast access to high quality approximation to solve m-OVRPTW problems;by repeatedly selecting the number of vehicles, solve the OVRPTW problem;finally,the 5 6 Group Solomon benchmarking data (VRPTW Benchmark Problem)for testing,ex-perimental results show that Application of tabu search algorithm in an open vehicle wiring problems for better results compared with similar studies from the minimum number of vehicles,the minimum,average vehicle trips vehicle trips,and so have better than the other algorithms.
Allocation and Routing of CRAF MD80 Aircraft
1990-03-01
5 II. Literature Review...................7 Formal Statement of the Vehicle Routing Problem ............ .. . .. .. ....... Vehicle...83 Appendix H: Example Vehicle Routing Problem Input 84 Appendix I: Example Vehicle Routing Problem Output 85 Appendix J: Spacefilling Curve...this problem is a stochastic vehicle routing problem with multiple depots. In this case, there are nine depots and 30 vehicles corresponding to nine
Research on Chaos Particle Swarm Optimization Algorithm for Vehicle Routing Problem%车辆路径问题的混沌粒子群算法研究
Institute of Scientific and Technical Information of China (English)
李毅; 陆百川; 刘春旭
2012-01-01
According to characters of the vehicle routing problem, a novel chaos particle swarm optimization ( CPSO) algorithm was proposed to solve the basic type of single depot and non-full load. After the chaos was introduced to the particle swarm optimization(PSO) , the random, regularity and ergodicity were used to initialize particles in order to cover the solution space of the vehicle routing problem in large range, enhance the ability for optimal route searching, and prevent the su-boptimal solution of the PSO in the way of exerting chaos disturbance at the place of suboptimal solution to help algorithm to abandon the current searching route. Illustration results showed the CPSO had the strong ability to search the global optimal in the vehicle routing problem.%针对车辆路径问题中单仓库非满载这一基本类型的具体特性,设计了一种混沌粒子群算法；利用混沌系统的随机性、规律性和遍历性初始化粒子,大范围覆盖车辆路径问题的解空间,加强算法最优路径的搜索能力；通过在求解过程中的次优路径处施加混沌扰动,使算法放弃当前求解的路径,避免结果为次优解.并通过试验验证了该算法在车辆路径问题中具有很强的寻优能力.
A algorithm for the Vehicle Problem
Directory of Open Access Journals (Sweden)
Aziz Ezzatneshan
2010-09-01
Full Text Available In this paper, we propose a hybrid ACO algorithm for solving vehicle routing problem (VRP heuristically in combination with an exact In the basic VRP, geographically scattered customers of known demand are supplied from a single depot by a fleet of identically capacitated vehicles. The intuition of the proposed algorithm is that nodes which are near to each other will probably belong to the same branch of the minimum spanning tree of the problem graph and thus will probably belong to the same route in VRP. Given a clustering of client nodes, the solution is to find a route in these clusters by using ACO with a modified version of transition rule of the ants. At the end of each iteration, ACO tries to improve the quality of solutions by using a local search algorithm, and update the associated weights of the graph arcs.
动态车辆路径问题的分区灵活分批TSP策略%Flexible nTSP strategy of dynamic vehicle routing problems
Institute of Scientific and Technical Information of China (English)
熊浩
2013-01-01
Dynamic vehicle routing problem(DVRP) is emerging topical issue for the vehicle routing problem, but its real-time optimization still needs to be improved. Therefore, the mod nTSP strategy is proposed based on the flexible nTSP strategy. And the competitive analysis of the new strategy shows the reason of the improvement. Finally, the simulation results show that the new strategy can reduce the average distance between the adjacent customers on the routing of vehicle while keeping the other system time constant, and the average customer system time can be reduced.%动态车辆路径问题是当前车辆路径问题的新兴热门问题，但其实时优化策略研究仍然有较大的改进空间。鉴于此，在一般分区分批旅行商问题(TSP)策略的基础上，提出了分区灵活分批TSP策略，并对策略有效性进行了分析。最后进行了实例仿真验证，结果表明，所提出策略能够减少车辆服务顾客的平均行驶距离，从而减少顾客的平均系统时间。
新型遗传算法求解车辆路径问题研究%New genetic algorithm for vehicle routing problem
Institute of Scientific and Technical Information of China (English)
张瑞锋; 汪同三
2012-01-01
We stated a universal mathematical model of vehicle routing problem with time windows. On the basis of analyzing the weakness of genetic algorithm in local search, a new stochastic approach called the genetic simulated annealing algorithm was proposed to solve vehicle routing problem with time windows.and made some experimental computations. The computational results demonstrated that the genetic simulated annealing a80lgorithm could overcome the weakness of genetic algorithm and local search algorithm, and the high quality solutions of the vehicle routing problem with time windows was obtained.%建立有时间窗车辆路径问题的数学模型,针对遗传算法在局部搜索能力方面的不足,提出将模拟退火算法与遗传算法相结合,从而构造有时问窗车辆路径问题的混合遗传算法,并进行实验计算.结果表明,用混合遗传算法求解该优化问题,可以在一定程度上克服遗传算法在局部搜索能力方面的不足和模拟退火算法在全局搜索能力方面的不足,从而得到质量较高的解.
Directory of Open Access Journals (Sweden)
Marco Antonio Cruz-Chávez
2016-01-01
Full Text Available A stochastic algorithm for obtaining feasible initial populations to the Vehicle Routing Problem with Time Windows is presented. The theoretical formulation for the Vehicle Routing Problem with Time Windows is explained. The proposed method is primarily divided into a clustering algorithm and a two-phase algorithm. The first step is the application of a modified k-means clustering algorithm which is proposed in this paper. The two-phase algorithm evaluates a partial solution to transform it into a feasible individual. The two-phase algorithm consists of a hybridization of four kinds of insertions which interact randomly to obtain feasible individuals. It has been proven that different kinds of insertions impact the diversity among individuals in initial populations, which is crucial for population-based algorithm behavior. A modification to the Hamming distance method is applied to the populations generated for the Vehicle Routing Problem with Time Windows to evaluate their diversity. Experimental tests were performed based on the Solomon benchmarking. Experimental results show that the proposed method facilitates generation of highly diverse populations, which vary according to the type and distribution of the instances.
Special Kind of Vehicle Routing Problem%一类特殊车辆路径问题(VRP)
Institute of Scientific and Technical Information of China (English)
李嘉; 王梦光; 唐立新; 宋建海
2001-01-01
A special kind of vehicle routing problem was described and its characteristics were analyzed. By defining the “fleet pattern”, a solving framework was presented, and a hybrid GA composed of GA and TS was presented. For solving the heterogeneous fleet VRP, the hybrid algorithm integrates the advantage of GA (good at global searching) and TS (good at mountain climbing). The fleet-task separately coding and decoding rules fully consider the characters of heterogeneous fleet VRP. The validity of the framework, model and algorithm were proved by some instances.%描述了一类特殊的车辆路径问题(VRP)－混合车队车辆路径问题．在分析问题特性的基础上,通过引入“车队模式”定义,提出了求解框架,设计了基于遗传算法和禁忌搜索启发式的混合算法．针对其中的混合车队车辆路径问题,所设计混合算法,利用了GA搜索全局性好,TS局部爬山能力强的特点．提出的车队、任务分段组合编码和解码规则充分考虑了混合车队车辆路径问题的特点．实例计算结果表明了框架、模型和算法的有效性．
多车场车辆路径问题及混合遗传算法%Multi-depot Vehicle Routing Problem with Hybrid Genetic Algorithm
Institute of Scientific and Technical Information of China (English)
党立伟; 孙小明
2012-01-01
在多车场车辆路径问题中,综合考虑车辆的行驶路程和使用车辆的数量能有效降低配送成本,考虑了这两方面的因素建立了相应的数学模型,运用混合遗传算法进行了求解,并通过实例证明了模型和算法的有效性.%About the multi-depot vehicle routing problem, considering the distance traveled by the vehicle and the number of vehicles together can effectively reduce distribution costs. The corresponding mathematical model by taking the two factors into account is established, solved the model by using genetic algorithms and demonstrate the effectiveness of the model and algorithm by example.
Real Time Conflict Resolution in Automated Guided Vehicle Scheduling
1988-05-01
use an optimal n-I vehicle routing as the basis for obtaining an optimal n vehicle routing. When only one vehicle is present, the one vehicle routing problem is...scheduling algorithms in general, pointing out that most fall in the class of NP- Hard problems. Lenstra and Rinnoy Kan [581 showed the vehicle routing problem is...Dial-a-ride problems. Vehicle Routing Problems The vehicle routing problem is a very important problem in distribution management. Vehicles are routed
需求可拆分的开放式车辆路径问题研究%Research on Split Delivery Open Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
李三彬; 柴玉梅; 王黎明
2011-01-01
The traditional Open Vehicle Routing Problem(OVRP) assumes that the demand of the clients can not be split and the type of vehicles is the same, but in the practical logistics distribution, the type of vehicles is not exactly the same, sometimes the transportation cost can be reduced by splitting the demand of clients to make the best of the loading capacity of vehicles.This paper proposes the Split Delivery Open Vehicle Routing Problem with Heterogeneous Vehicles(SDOVRPHV), presents mathematic model of the integer programming of the problem, solves it with Tabu search algorithm and improves the generation of the initial solution and neighborhood structure in the algorithm.By experiments, the validity of the model is validated, and the results are compared with the traditional OVRP which indicates that the algorithm can reduce effectively the transportation cost.%传统的开放式车辆路径问题假设客户的需求不可拆分、车辆类型相同,但在实际的物流配送中,车辆类型不完全相同,对需求的拆分能充分利用车辆的装载能力,降低运输成本.为此,提出需求可拆分的不同种车辆的开放式车辆路径问题,给出整数规划的数学模型,利用禁忌搜索算法对该问题求解,改进算法中初始解和邻域结构的产生过程.通过实验验证模型的有效性,并将结果与传统的开放式车辆路径问题进行比较,表明该算法可有效减少运输成本.
Vehicle Routing under Uncertainty
Máhr, T.
2011-01-01
In this thesis, the main focus is on the study of a real-world transportation problem with uncertainties, and on the comparison of a centralized and a distributed solution approach in the context of this problem. We formalize the real-world problem, and provide a general framework to extend it with
Research on Vehicle Routing Problem Based on Improved Genetic Algorithm%改进遗传算法下的车辆路径问题研究
Institute of Scientific and Technical Information of China (English)
陈果
2016-01-01
The vehicle routing problem is a typical combinatorial optimization problem.With the continuous improvement of logistics requirements, the basic genetic algorithm has been difficult to meet the needs of customers.The basic genetic algorithm in solving this kind of problem,often appear premature convergence, and delivery time of the vehicle has the defects of limited,can not to solve the optimization of this kind of problem,so this paper uses improved genetic algorithm on vehicle routing problem were studied,and explore the improved genetic algorithm in solving the vehicle routing problem is effective.%车辆路径问题是一种典型的组合优化类问题，随着客户对物流要求的不断提升，基本的遗传算法已经很难满足客户的需求。基本的遗传算法在求解这类问题的时候，经常会出现早熟收敛，以及对车辆的运送时间存在限制等方面的缺陷，不能够对这类问题进行最优化求解，所以本文采用改进的遗传算法就车辆路径问题进行研究，并探究改进下的遗传算法在求解车辆路径问题时的有效性。
Location and Routing of the Defense Courier Service Aerial Network
1991-03-01
The Vehicle Routing Problem ................ 8 Vehicle Routing Problem Modifications ...... .0 Multiple Depot Problems...several specific formulations are applicable to the DCS aerial network. Those addressed in this review include: 1) the Vehicle Routing Problem (VRP); 2...methodologies show great promise for adaptation to the DCS network. The Vehicle Routing Problem The Travelling Salesman Problem seeks the shortest route which
Study on vehicle routing problem based on heuristic ant colony optimization%基于启发式蚁群算法的VRP问题研究
Institute of Scientific and Technical Information of China (English)
刘晓勇; 付辉
2011-01-01
When Ant Colony Optimization algorithm (ACO) is applied to vehicle routing problem, it always spends much time and has worse solutions.This paper uses ACO based on a heuristic method for vehicle routing problem.This heuristic method combines distance matrix with saving route matrix to assign initial pheromone matrix.Three benchmark datasets are chosen to verify performance of the new algorithm. Experiments show that ant colony optimization based on heuristic information has better solution and spends less time.%针对蚁群算法求解VRP问题时收敛速度慢,求解质量不高的缺点,把城市和仓库间的距离矩阵和路径节约矩阵信息融入到初始信息素矩阵中作为启发式信息引入到蚁群算法中用于求解有容量限制的车辆路径规划问题(CVRP),在三个基准数据集上的实验研究表明,基于启发式信息的蚁群算法与基本蚁群算法相比能够以较快的速度收敛到较好的解.
车辆路径规划的数学模型及算法综述%REVIEWS ON MATHEMATICAL MODELS AND ALGORITHMS FOR VEHICLE ROUTING PROBLEM
Institute of Scientific and Technical Information of China (English)
高晓菲
2015-01-01
Vehicle routing problem (VRP)is a hot spot.In the process of transportation,the reasonablevehicle route can save manpower,reduce transportation cost on the basis of the meet the requirements to a greatdegree.Models and algorithms play an important role in the research of VRP.The present models and algorithms ofVRP still have some shortcomings.In order to solve the problem,the mathematical models and algorithms of VRPare discussed in this paper.%车辆路径规划问题（Vehicle Routing Problem，VRP）是一项研究热点。在运输过程中，对车辆进行合理的路径规划可以在满足运输要求的基础上最大程度地节约人力物力，降低运输成本。在对车辆路径规划的研究过程中，模型和算法起着关键性作用。目前已有的模型和算法还存在一些不足。为此，对车辆路径规划问题的数学模型和算法进行了探讨。
Vehicle Load Detection System Based on Differential Capacitance Sensor%基于差动式电容传感器的车辆载荷检测系统
Institute of Scientific and Technical Information of China (English)
陈梅
2011-01-01
针对传统车辆载荷检测系统存在的不足,提出了一种电容式车辆载荷检测系统,该系统的载荷检测传感器采用差动式结构,大大提高了测量的灵敏度和非线性,电容测量线路采用差动脉冲宽度调制集成测量电路,数据的采集和处理采用自带A/D转换器的STC89LE516AD单片机芯片,数据通信采用无线通信模式.这种载荷检测系统结构简单、成本低廉、安装方便、性能可靠、测量电路简单、抗干扰性好,可用于交通数据的采集和便携式测量,具有良好的使用前景.%Aiming at the shorrage of present vehicle load detection system, a capacitive vehicle load detection system is introduced. In the system, the load detection sensor used differential structure, which greatly improved the measurement sensitivity and non-linear, the capacitance measurement circuit used differential pulse width modulation integrated circuit, data acquisition and processing used STC89LE516AD single chip which has its own A / D converter, data communication used wireless communication mode. This load detection system has simple structure, low cost, easy installation, reliable performance,simpLe measurement circuit and good anti-jamming. The system can be used for traffic data collection and portable measurement, and has good application prospects.
Research on Vehicle Routing Problem Based on Improved Genetic Algorithm%基于改进遗传算法的车辆路径问题研究
Institute of Scientific and Technical Information of China (English)
朱志勇; 刁洪祥
2011-01-01
车辆路径问题是一个典型的组合优化类问题,而传统的算法无法满足顾客需求对物流运输提出的要求.遗传算法是求解此类问题的方法之一,针对遗传算法容易出现早熟收敛,以及车辆运送的时间限制,该文采用改进的遗传算法对有时间窗的车辆路径问题进行分析,实验验证了算法的有效性.%Vehicle routing problem is a typical combinational optimization problem, and the traditional algorithms can not meet customer needs for logistics transport. Genetic algorithm is one of the methods used to solve -VRP,because of premature convergence of genetic algorithm and the time constraints of vehicles transporting, this paper analysis vehicle routing problem with Time Window using an improved genetic algorithm. Experiment data prove the effectiveness of the algorithm.
Nowakowski, Piotr
2017-02-01
Waste electrical and electronic equipment (WEEE), also known as e-waste, is one of the most important waste streams with high recycling potential. Materials used in these products are valuable, but some of them are hazardous. The urban mining approach attempts to recycle as many materials as possible, so efficiency in collection is vital. There are two main methods used to collect WEEE: stationary and mobile, each with different variants. The responsibility of WEEE organizations and waste collection companies is to assure all resources required for these activities - bins, containers, collection vehicles and staff - are available, taking into account cost minimization. Therefore, it is necessary to correctly determine the capacity of containers and number of collection vehicles for an area where WEEE need to be collected. There are two main problems encountered in collection, storage and transportation of WEEE: container loading problems and vehicle routing problems. In this study, an adaptation of these two models for packing and collecting WEEE is proposed, along with a practical implementation plan designed to be useful for collection companies' guidelines for container loading and route optimization. The solutions are presented in the case studies of real-world conditions for WEEE collection companies in Poland.
Institute of Scientific and Technical Information of China (English)
饶卫振; 金淳; 王新华; 刘锋
2014-01-01
经典车辆路径问题(vehicle routing problem,VRP)模型不考虑道路的坡度,通常以最小化车辆行驶总距离、总耗时或派送车辆数为目标函数.在考虑道路坡度因素的基础上,提出了以配送车辆总能耗最小为目标的低碳车辆路径问题模型(energy consumption minimizing low-carbon VRP,ECM-LCVRP);然后,以带能力约束的车辆路径问题(capacitated VRP,CVRP)为参照,分析了ECM-LCVRP的解空间大小及基本算法改进法则在ECM-LCVRP中的执行复杂度,发现ECM-LCVRP较CVRP更加难以求解,并且分析了不同坡度下ECM-LCVRP和CVRP的区别与联系;另外,基于配送方案的能耗值与行驶距离正相关的规律,提出了求解不同道路坡度环境下ECM-LCVRP的双目标策略(two objective strategy,TOS);最后,设计了40个ECM-LCVRP算例,并采用综合了算法基本改进规则的混合局部搜索算法(hybrid local search,HLS)和HLS+TOS两种方式求解,求解结果表明:在不同的运算时间内,TOS策略均能够有效地提高HLS的求解质量,且求解时间越短,TOS的效果越明显.
Application of Improved Genetic Algorithm in Vehicle Routing Problem%改进遗传算法在车辆路径问题中的应用
Institute of Scientific and Technical Information of China (English)
张华庆; 张喜
2012-01-01
The mathematical model of Vehicle Routing Problem is developed in this paper. To improve the search rate of genetic algorithm and avoid the premature phenomenon of population, an improved genetic algorithm, in which the fitness function is defined with dynamic linear method and its cross-operator is improved to adopt a large variation of operation for Vehicle Routing Problem, is designed, and the detailed computation steps of the genetic algorithm are given. Finally, the genetic algorithm is applied to a numerical example. The results indicate that the genetic algorithm is better than the genetic algorithm designed in the existing reference literature over the computational performance. Furthermore, the improved strategies of the genetic algorithm are not only simple but also effective in solving the Vehicle Routing Problem.%建立了车辆路径问题的数学模型.为了提高遗传算法的搜索速率,避免种群出现“早熟”现象,对适应度函数采用动态线性标定方式,改进交叉算子,采用大变异操作,设计出了求解车辆路径问题的改进遗传算法并给出了具体的计算步骤.应用该遗传算法进行了实例计算,取得了比较满意的结果.计算结果表明,该遗传算法在计算性能上优于参考文献中设计的遗传算法.同时也表明,对遗传算法的改进策略不仅简单而且对求解VRP问题是有效的.
Optimal Design of Incident Vehicle Routing Problem for Dangerous Goods%危险品关联运输调度问题的优化设计
Institute of Scientific and Technical Information of China (English)
向周; 蔡延光; 汤雅连
2014-01-01
Aiming at IVRPHTW (Incident Vehicle Routing Problem with Hard Time Windows ) and VRP(Vehicle Routing Problem) of dangerous goods in practical application , this paper introduces and modifies the fundamental principle of CGA ( Chaos Genetic Algorithm ) adjusting adaptively crossover probability and mutation probability , bringing simulated annealing mechanism in the algorithm, and applying cluster analysis and the modified algorithm to solve IVRPHTW , as well as compared with Genetic Algo-rithm ( GA) .The results show that CGA is feasible to solve IVRP of dangerous goods , and better than GA during the optimization process.%针对带硬时间窗的关联运输调度问题（ Incident Vehicle Routing Problem with Hard Time Windows ， IVRPHTW），联系实际应用中危险品的车辆路径问题，介绍了混沌遗传算法的基本原理，并对其进行改进，自适应地调整交叉概率和变异概率，引进了模拟退火机制，并用改进的算法来对IVRPHTW求解，然后与遗传算法求解此模型的结果相比较。实例证明该算法求解危险品的关联运输调度问题是可行的，且优于传统的遗传算法。
Simulation Analysis of Logistics Distribution Vehicle Routing Problem%物流配送车辆路径优化的仿真分析
Institute of Scientific and Technical Information of China (English)
张玲雅
2015-01-01
The current development of the logistics industry,based on the development needs of the industry,as well as traditional logistics short board to reduce logistics costs can not be overcome,the urgent need for logistics distribution vehicle routing optimization,thus effectively reducing logistics costs,based on this,propose an ant colony algorithm for logistics distribution vehicle routing optimization algorithm,aimed at establishing a basis for the mathematical model,the logistics vehicle routing problem using ant colony optimization algorithm to solve subsequent experiments concluded that the algorithm achieved significant results,conducive to the logistics and distribution reduce costs for the development of the current logistics enterprises of great significance.%当前物流行业发展中，基于行业的发展需要，以及传统物流在降低物流运输成本方面无法克服的短板，急需进行物流配送车辆路径优化，从而有效地降低物流配送成本，基于此，文中提出一种蚁群算法的物流配送车辆路径优化算法，旨在建立数学模型的基础上，对物流车辆路径的问题采用蚁群算法进行求解优化，后续实验得出，该算法效果显著，利于对物流配送成本的降低，对于当前物流企业的发展意义重大。
基于类电磁机制算法的关联运输调度问题%Electromagnetism-like Mechanism Algorithm for Related Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
郭帅; 蔡延光; 汤雅连
2013-01-01
介绍了基本的类电磁机制算法的原理并对其进行改进,并用改进的算法来对单车场单车型的关联物流运输调度问题(Incident Vehicle Routing Problem,IVRP)求解,然后与遗传算法求解此模型的结果相比较.实例证明该算法求解关联运输调度问题是可行的,且优于传统的遗传算法.
物流配送线路优化的改进遗传算法研究%A Study of Modified Genetic Algorithm for Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
高鹏; 徐瑞华
2006-01-01
物流配送线路优化问题,即车辆路线问题(VRP,Vehicle Routing Problem)是组合优化领域中的著名NP(Nonlinear Programming)难题. 本文以VRP为基础,建立该问题的数学模型,设计了改进的遗传算法,通过大量计算机计算分析验证,此改进算法对VRP有良好的近似解和较高的收敛速度.
基于ACS-GA算法的车辆路径问题研究%An ACS-GA Hybrid Optimization Method to Solve Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
赵婉忻; 曲仕茹
2011-01-01
Vehicle routing problem is an important research area in intelligent transportation and business logistics. Planning the vehicle routes reasonably, reducing the delivery mileage and minimizing the cost of logistic distribution are great significance to increase economic efficiency. The paper focuses on vehicle routing problem with time windows in logistic distribution and establishes an improved mathematical model in which the delivery time and delivery distance is shortest. A novel hybrid optimization method integrating ant colony system with genetic algorithm ( ACS - GA) is presented. The initial solution is obtained by ant colony system. A genetic algorithm is used to improve the performance of ACS by reproduction, crossover and mutation operations. The ACS - GA hybrid optimization method can overcome the premature phenomenon and enhance the global search ability. Based on the benchmark datasets of vehicle routing problem with time windows, the experimental results demonstrate that the proposed method has a better ability to search the global optimal solution than other optimization methods.%物流配送车辆路径问题是智能交通和商业物流领域中一个重要研究方面.合理规划车辆的行驶路线,减少配送里程,降低物流成本,对提高经济效益具有重要意义.重点分析了带时间窗的物流配送车辆路径问题,建立了兼顾配送时间与配送距离最短的改进数学模型.提出了基于蚁群系统算法和遗传算法相融合的混合算法.该算法利用蚁群系统算法得到初始解,运用遗传算法中复制、交叉、变异操作对解的种群多样性进行扩充,克服了蚁群系统算法的早熟现象,增强了算法的全局搜索能力.基于标准数据集的实验结果表明,该算法与其他优化方法相比较,具有较好的搜索车辆路径最优解的能力.
Suthikarnnarunai, N.; Olinick, E.
2009-01-01
We present a case study on the application of techniques for solving the Vehicle Routing Problem (VRP) to improve the transportation service provided by the University of The Thai Chamber of Commerce to its staff. The problem is modeled as VRP with time windows, split deliveries, and a mixed fleet. An exact algorithm and a heuristic solution procedure are developed to solve the problem and implemented in the AMPL modeling language and CPLEX Integer Programming solver. Empirical results indicate that the heuristic can find relatively good solutions in a small fraction of the time required by the exact method. We also perform sensitivity analysis and find that a savings in outsourcing cost can be achieved with a small increase in vehicle capacity.
Energy Technology Data Exchange (ETDEWEB)
Marty, M. S.; Domoradzki, J. Y.; Hansen, S. C.; Timchalk, Chuck; Bartels, M. J.; Mattsson, Joel L.
2007-12-01
There is a paucity of data on neonatal systemic exposure using different dosing paradigms. Male CD (Sprague-Dawley derived) rats at postnatal day (PND) 5 were dosed with chlorpyrifos (CPF, 1 mg/kg) using different routes of exposure, vehicles, and single vs. divided doses. Blood concentrations of CPF and its primary metabolite, trichloropyridinol (TCP), were measured at multiple times through 24 h. Groups included: single gavage bolus vs. divided gavage doses in corn oil (1 vs 3 times in 24 h), single gavage bolus vs. divided gavage doses in rat milk, and subcutaneous administration in DMSO. These data were compared with lactational exposure of PND 5 pups from dams exposed to CPF in the diet at 5 mg/kg/day for four weeks or published data from dams exposed to daily gavage with CPF at 5 mg/kg/day. Maternal blood CPF levels were an order of magnitude lower from dietary exposure than gavage (1.1 vs 14.8 ng/g), and blood CPF levels in PND 5 pups that nursed dietary-exposed or gavage-exposed dams were below the limit of detection. Single gavage doses of 1 mg/kg CPF in corn oil vehicle in pups resulted in CPF blood levels of 49 ng/g, and in milk vehicle about 9 ng/g. Divided doses led to lower peak CPF levels. A bolus dose of 1 mg/kg CPF in DMSO administered sc appeared to have substantially altered pharmacokinetics from orally administered chlorpyrifos. To be meaningful for risk assessment, neonatal studies require attention to the exposure scenario, since route, vehicle, dose and frequency of administration result in different systemic exposure to the test chemical and its metabolites.
Clustering algorithm for split delivery vehicle routing problem%需求可拆分车辆路径问题的聚类求解算法
Institute of Scientific and Technical Information of China (English)
刘旺盛; 杨帆; 李茂青; 陈培芝
2012-01-01
In the traditional vehicle routing problems, customer demands are usually assumed that they can not be split. That is to say, a customer can only be severed by a vehicle. In fact, split delivery requires fewer vehicles, which reduces transportation costs. This paper analyzes the solution＇s characteristics of split delivery vehicle routing problem, and also proves the situations that customers＇ demands can not be split. A clustering algorithm meeting the solution＇s characteristics is designed to solve this problem. Compared with ant colony algorithm and tabu search algorithm, the proposed algorithm is demonstrated to obtain optimal solution more effectively through the simulation, and it is an effective method to solve split delivery vehicle routing problem.%针对传统的车辆路径问题通常假设客户的需求不能拆分，即客户的需求由一辆车满足，而实际上通过需求的拆分可使需要的车辆数更少，从而降低配送成本的问题，分析了需求可拆分的车辆路径问题的解的特征，证明了客户需求不宜拆分应满足的条件，设计了符合解的特征的聚类算法，并对其求解．通过实验仿真，将所提出的聚类算法与蚁群算法和禁忌搜索算法进行比较，所得结果表明了所提出的算法可以更有效地求得需求可拆分车辆路径问题的优化解，是解决需求町拆分车辆路径问题的有效方法．
Route planning method for multiple vehicles coordinated target assignment%多机协同与多目标分配任务规划方法
Institute of Scientific and Technical Information of China (English)
魏铁涛; 屈香菊
2009-01-01
多架飞机攻击多个目标区域是现代作战方式的重要特征,多机协同与多目标分配问题是提高团队作战效能的关键.针对该问题,综合考虑飞机能力差异、协同方式和任务环境的变化,提出多机协同目标分配的任务规划方法.建立了基于能力裕度评价的多机协同目标分配问题的数学模型.对多目标分配问题,通过约束飞机的能力裕度对分配方案进行筛选,保证在战场环境发生改变时任务兵力的完整性.仿真结果表明,采用这种方法得到的目标分配方案,适应任务目标突发性变化的能力更强.%Multiple vehicles coordinated target assignment is the key problem to improve the efficiency of team fighting in the mission of multiple vehicles attacking multiple target regions. A route planning method for this problem was presented with consideration of the differences in vehicle ability, cooperation mode and the abrupt change of the battle field situation. Based on the evaluation of vehicle residual ability, a mathematical model of multiple vehicles coordinated target assignment had been built. The target assignment schemes were chosen by constraints on the vehicle residual ability, then the integrity of the military strength was ensured. The final simulation results of this model show that a stronger adaptability for abrupt change of mission objective can be gained.
Research of Vehicle Routing Problem Based on Fuzzy Time Windows%基于模糊时间窗的车辆调度问题研究
Institute of Scientific and Technical Information of China (English)
王旭坪; 张凯; 胡祥培
2011-01-01
An increasing number of enterprises are focusing on the vehicle routing problems (VRP) because of expanded logistics support. VRP belongs to typical NP-Hard problems. An enterprise typically spends 25% to 30% of total expenses on vehicle routing problems because they can affect economic efficiency and customer benefits. Therefore, it is important to research VRP and optimize logistics activities.Exiting literature has focused on the vehicle routing problem with hard time and soft time windows. In the VRP with hard time window, the service time must fall within each customer' s time window. Due to the limitation of hard time window and the number of available vehicles, it is often unable to find feasible schedules. To deal with issues pertaining to the violation of time window, researchers have proposed the concept of "soft time window". In the VRP with soft time window, a penalty cost is added once a time window is violated, and the penalty cost is often assumed to be linear with the degree of violation. In some cases, violation of time window does not directly incur any penalty cost, although the satisfaction levels of customers may drop and lead to benefit loss in the long term. In many realistic applications, the hard time window or soft time window does represent customer requirements very well. Under these circumstances, the fuzzy processing of time window can reflect customers' requirements well and truly. Until now, few studies have addressed VRP-with fuzzy time window when the number of vehicle is limited. There are many real-life situations where the number of vehicle is limited, such as logistics distribution, post express and so on. Thus, this paper proposes and solves vehicle routing problems based on the fuzzy time window and a definite number of vehicles. In this paper, a fuzzy membership function is used to characterize customers' satisfaction levels by analyzing customers' practical requirements of the service time window.A multi-objective model
Institute of Scientific and Technical Information of China (English)
LI Bei-zhi; ZHOU Ya-qin; LAN Shi-hai; YANG Jian-guo
2007-01-01
The vehicle routing and scheduling (VRS)problem with multi-objective and multi-constraint is analyzed, considering the complexity of the modern logistics in city economy and daily life based on the system engineering. The objective and constraint includes loading,the dispatch and arrival time, transportation conditions,total cost, etc. An information model and a mathematical model are built, and a method based on knowledge and biologic immunity is put forward for optimizing and evaluating the programs dimensions in vehicle routing and scheduling with multi-objective and multi-constraints. The proposed model and method are illustrated in a case study concerning a transport network, and the result shows that more optimization solutions can be easily obtained and the method is efficient and feasible. Comparing with the standard GA and the standard GA without time constraint,the computational time of the algorithm is less in this paper.And the probability of gaining optimal solution is bigger and the result is better under the condition of multi-con,traint.
A New Vehicle Routing Problem and It's Two Stage Algorithm%一类新的车辆路径问题及其两阶段算法
Institute of Scientific and Technical Information of China (English)
王科峰; 叶春明; 唐国春
2010-01-01
本文结合汽车零部件第三方物流业的实际背景,提出了一类新的车辆路径问题,它是一种带时间窗约束的分车运输同时收发车辆路径问题(简称SVRPSPDTW).接着给出了问题的模型,并提出求解问题的启发式算法;两阶段算法.最后在改进的Solomn的算例的基础上,进行了数值试验.%In this paper,a new vehicle routing problem,split and simultaneous pickup and delivery vehicle routing problem with time windows constraints(SVRPSPDTW),was provided for the first time under the actual background in the third party logistics of auto parts.Then the mathematic model of this problem and the heuristic algorithm to solve the problem,i.e.two stage algorithm,was given.In the end,the computational experiment was done based on the modified Solomn's benchmark.
基于真实路网的车辆路径问题研究%Solution to the Real Road Network Based Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
孙国华
2011-01-01
The paper proposea a modeling method for vehicle routing problem based on real road network which processes the shortest path problem and vehicle routing problem simultaneously.In a subsequent simulation experiment, the model proposed above is compared to the traditional one where the two yield the same optimal solution, yet the one of the paper is superior in computation time.%车辆路径问题(VRP)是广泛应用于物流配送的组合优化问题.在实际应用中,传统的处理方法是先利用路网信息求出任意两点间最短路,生成完全连通图,然后进行VRP的优化求解,这样会浪费时间和空间,降低求解效率.因此,提出了一种基于真实路网的VRP建模方法,把任意两点间最短路的求解与VRP联合起来,通过仿真实验与传统的处理方法进行了比较,两种方法得到了相同的最优解,但基于真实路网的VRP建模方法在计算时间方面占优.
Vehicle Routing Problem with Integration of Resources%求解整合资源条件下的运输调度问题
Institute of Scientific and Technical Information of China (English)
江泽东; 蔡延光; 汤雅连; 杨军; 朱君
2014-01-01
针对传统的物流运输调度问题(Vehicle Routing Problem,VRP)中车辆之间不协作会造成资源浪费的情况,提出整合资源条件下的运输调度问题(Vehicle Routing Problem with Integration of resources,VRPIR),建立了相应的数学模型.由于混沌具有良好的遍历性,而粒子群优化算法(Particle Swarm Optimization,PSO)具有概念简单,参数少,容易实现等优点,将混沌优化方法引入到粒子群优化算法中,应用混沌粒子群优化算法(Chaos Particle Swarm Algorithm,CP-SO)求解VRPIR和VRP,并用CPSO和PSO分别求解VRPIR,实验结果证明该算法优于粒子群优化算法,也证明了提出的VRPIR模型优于VRP,能节省资源,且最小化成本.
Memettc algorithm for vehicle routing problem with time windows.%带时间窗车辆路径问题的文化基因算法
Institute of Scientific and Technical Information of China (English)
王君; 李波
2012-01-01
针对物流配送中带时问窗的车辆路径问题(Vehicle Routing Problem with Time Windows,VRPTW),建立了数学模型,并设计了求解VRPTW的文化基因算法.种群搜索采用遗传算法的进化模式,局部搜索采用禁忌搜索机制,并结合可行邻域结构避免对不可行解的搜索,以提高搜索效率.与单纯的遗传算法和禁忌搜索算法进行对比实验,表明该算法是求解VRPTW的一种有效方法.%The Vehicle Routing Problem with Time Windows(VRPTW) is addressed in this paper. A mathematical model is designed and a memetic algorithm is proposed for VRPTW. The pattern of population search is genetic algorithm and the local search used tabu. The feasible neighborhoods are integrated into the algorithm to avoid the search for infeasible solutions, thus it improves search efficiency. Compared with the pure genetic algorithm and the tabu search, computational experiments on Solomon benchmarks show the effectiveness of the proposed memetic algorithm for VRPTW.
Hybrid Algorithm for Open Vehicle Routing Problem%开放式车辆路径问题的混合算法
Institute of Scientific and Technical Information of China (English)
钟雪灵; 王雄志
2011-01-01
为研究开放式车辆路径问题(Open Vehicle Routing Problem,OVRP),建立了数学模型.针对遗传算法(Genetic Algorithm,GA)与禁忌搜索算法(Tabu Search Algorithm,TSA)的不足,提出了一个采用GA和TSA相结合的混合算法求解OVRP.混合算法中以GA为主,把TSA用在GA的变异操作中,增强算法的爬山能力.通过仿真,将提出的混合算法与文献中其它算法比较,结果表明它可以快速、有效求得最优解或近似解.%This paper studies the open vehicle routing problem(OVRP). First, the mathematics model of OVRP is described. Then hybrid algorithm of genetic algorithm (GA) and tabu search algorithm (TSA) are proposed on the basis of analyzing the weakness of GA and TSA. The GA is taken as the main part, and the TSA is used in the big cycle of the GA. So, the hill - climbing power of the algorithm is increased, and the probability of obtaining the optimal solution is increased. Finally, the proposed hybrid algorithm is compared with other algorithms with simulation results, which demonstrates that it is an efficient and effective method for finding the optimum or approximate solution.
Improved Ant Colony Algorithm for Period Vehicle Routing Problem%改进蚁群算法优化周期性车辆路径问题
Institute of Scientific and Technical Information of China (English)
蔡婉君; 王晨宇; 于滨; 杨忠振; 姚宝珍
2014-01-01
周期性车辆路径问题（PVRP）是标准车辆路径问题（VRP）的扩展，PVRP将配送期由单一配送期延伸到T（ T＞1）期，因此，PVRP需要优化每个配送期的顾客组合和配送路径。由于PVRP是一个内嵌VRP的问题，其比标准VRP问题更加复杂，难于求解。本文采用蚁群算法对PVRP进行求解，并提出采用两种改进措施---多维信息素的运用和基于扫描法的局部优化方法来提高算法的性能。最后，通过9个经典PVRP算例对该算法进行了数据实验，结果表明本文提出的改进蚁群算法求解PVRP问题是可行有效的，同时也表明两种改进措施可以显著提高算法的性能。%Period Vehicle Routing Problem(PVRP)is a generalized classic vehicle routing problem (VRP), in which the planning period is extended to a t-day period .Therefore , custom group and route should be optimized every day in PVRP.Embedded in VRP, PVRP is too complicated to be solved .As many route operations are formulated in a certain period, PVRP is very popular in practice.In recent years, distribution centers have paid much attention to the problem of vehicle delivery with the growing fuel cost and fierce supply chain competition . Especially in some situations , vehicles have to serve some fixed customers in a given period , and besides , the service times of each customer are settled in advance .Optimization of the repetitive operations will significantly save cost .Many researches have shown that the heuristic method based on the simulation of biological is very suitable for solving large-scale combinatorial optimization problem .Ant colony optimization ( ACO) is founded on the behavior of ant colony foraging in nature , which has been proved to be feasibility for solving VRP problems in lots of research .Therefore , this paper presents an improved ant colony optimization ( IACO ) , in which a multi-dimension pheromone matrix and a local optimization strategy based on
Empirical study on optimizing of vehicle route in regional distribution%区域配送中车辆路径优化的实证研究
Institute of Scientific and Technical Information of China (English)
肖建辉
2011-01-01
Regional distribution is ubiquitous as logistics activities, and the key to optimize distribution system is the distribution route optimization. The substance of the route optimization in distribution is the problem of the shortest path and the problem to dispatch vehicles that are with the same start and end point in a single field, non-full loaded, and the time window limited. Taking H company as an example, excel modeling method, and economical method used, the paper analyzes the route optimizing in regional distribution.%区域配送是普遍存在的物流活动,配送路径优化是配送系统优化的关键.区域配送中的路径优化问题实质是最短路径问题和起讫点相同的单车场非满载有时间窗约束的车辆调度问题,以H公司为例,采用Excel建模法和节约法对区域配送中的车辆路径优化进行了分析和实证研究.
突发事件下车辆路径问题的动态规划算法%Dynamic Programming Algorithm of Vehicle Routing Problems under Emergencies
Institute of Scientific and Technical Information of China (English)
欧微; 焦丽萍
2011-01-01
突发事件下的车辆运输具有紧迫性、动态性和随机不确定性等特点.本文研究了突发事件下动态车辆路径问题的数学模型,构建了一种基于混沌优化的动态规划算法,为此通过路径计算和动态规划两个模块来实现车辆路径的动态规划.为实现从混沌运动空间向问题可行解空间的有效映射,提出了相应的编码方法和操作算子.最后进行仿真,通过对静态环境、道路受损和道路拥塞三种情况的分析,验证了实时修订路经的有效性和实用性,为突发事件提供参考.%The vehicle transportation under emergencies is a kind of emergent, dynamic and random problems. The mathematics model of Dynamic Vehicle Routing Problems (DVRP) under emergencies is proposed, and an ap-proach solving DVRP based on chaos optimization is formulated, in which a route computing module and a dynamic programming module are introduced, and the corresponding coding method and operators are proposed to mapping the chaos space to feasible solution space. Finally, three cases of initial - state, road - damaged and road - congested are analyzed separately to demonstrate the necessary of real - time route adjusting and the efficiency of the proposed algorithm by computer simulations.
基于进化策略的开放式车辆路径问题%Research on Evolution Strategy for Open Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
朱超; 许兆义; 尹智宏
2011-01-01
Open Vehicle Routing Problem (OVRP) is an extension of the classic vehicle routing problem (VR P), in which the vehicle does not return to the starting depot after serving the last customer. The paper presents a modified evolution strategy for the OVRP. The proposed method generates the initial population based on a strictly generational course and offsprings are produced solely via mutation based on different trajectories. A multi-parent recombination operator is used to determine the strategy parameters. The paper also examines the performance of the proposed method by use of some well-known examples. Results show that the proposed ES is an effective tool for OVRP.%开放式车辆路径问题(OVRP)是标准车辆路径问题(VRP)的一个扩展,该问题是针对车辆在服务完最后一个顾客点后不需要回到车场的车辆路径问题.针对这类问题,提出了一种改进的进化策略.首先通过优化选择方案研究初始种群,然后基于轨迹进行变异获得子代,同时通过多父代组合来确定每个个体的策略参数.最后,通过若干经典OVRP实例对该算法进行了检验,结果表明这种改进的进化策略是一种求解OVRP问题的有力工具,
Vehicle ROuting Problem with Tw0 Type Vehicles n the Case Of StOchastic Demand%两种类型车辆随机需求路由问题
Institute of Scientific and Technical Information of China (English)
刘浩; 袁健; 卢厚清
2001-01-01
主要研究两种类型车辆随机需求路由问题。因为两种类型车辆随机需求路由问题的处理不同于单类型车辆随机需求路由问题，引进了单位容积和路程的花费的新概念，在服务仅能失败一次的情况下，结合车辆的容积和最大服务结点数，根据平均花费和最大服务结点数之间的关系，得到了两个派车策略，节约了计算量，使得两阶段的模拟退火算法能更有效地解决问题。对需求为二项分布下的VRP(Vehicle routing problem)问题作了数值实验.给出了派车方案和总的平均花费，得到了较好的结果。%The vehicle routing problem (VRP) with two different types of vehicles in the case of stochastic demand is studied. Because this problem is different from the VRP with one type vehicle in the case of stochastic demand, this paper introduces a new conception, the cost of unit capacity and distance. Provided that there is only one chance of failure, we connect the capacity of the vehicles with the maximum nodes of service. According to the mean cost, the paper discusses the strategy of dispatching vehicles. On the basis of the relation between the maximum nodes of service, we get two strategies and decrease the amount of calculation, making the two-phase simulated annealing algorithm solve the prob lem effectively. Under the binomial distribution the digital experiment is done. The experiment gives the dispatching plan and the total mean cost. A good result is obtained.
Research on the Open Incident Vehicle Routing Problems%开放式关联运输调度问题的研究
Institute of Scientific and Technical Information of China (English)
汤雅连; 蔡延光; 黄刚
2013-01-01
Aiming at Open Incident Vehicle Routing Problem with Soft Time Windows ( OIVRPSTW) and relating to the VRP( Vehicle Routing Problem ) of goods supply in chain stores , this paper introduces the fundamental principle of PSO ( Particle Swarm Optimization ) , adopting the nonlinear dynamic self -adapting method to adjust inertia weight factor , so that the weight factor can change along with the target value , combined with the advantage of using chaos to generate initial population and design a kind of CPSO(Chaos Particle Swarm Optimizaton).Meanwhile, SA (simulated annealing) mechanism is brought in the CGA (Chaos Genetic Algorithm), adjusting crossover probability and mutation probability adaptively .At last, both of the modified algorithms are applied to solve OIVRPSTW , so does GA ( Genetic Algorithm ) .The result shows that the advantage of using chaos to generate ini-tial population is flexible to solve this kind of OIVRP and can obtain the satisfied result .%针对带软时间窗的开放式关联运输调度问题（ Open Incident Vehicle Routing Problem with Soft Time Windows， OIVRPSTW），联系实际应用中连锁店超市中货物供应的车辆路径问题，介绍了粒子群算法的基本原理，采用一种非线性动态自适应调节惯性权重因子的方法，使得惯性系数会随着粒子目标值的变化而自动改变，结合混沌搜索产生初始种群的方法，设计了一种混沌粒子群优化算法。同时也设计了引入了模拟退火机制的混沌遗传算法，自适应地调整交叉概率和变异概率。并用这两种算法来对OIVRPSTW求解，然后与基本的遗传算法求解此模型的结果相比较。实例证明用混沌搜索产生初始种群的方法在求解此类开放式关联运输调度问题是可行的，能取得令人满意的效果。
车辆路径问题的连接点选择节约算法%Connection Point Selection Saving Algorithm Solving the Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
邵俊岗; 郑芳瑜
2015-01-01
为了深入研究车辆路径问题中节约算法的应用，通过具体数据比较与分析了传统CW算法和改进后的分割节约算法得出的配送方案．发现针对C－W算法下运输车辆数目已经最优的情况，允许分割配送的节约算法反而增加了配送里程，路径交叉的情况却没有得到改善，因此此方法不再适用．因此，基于传统Clarke－Wright节约算法，对连接点进行选择来解决这一问题．通过matlab7．0对具体的实例进行了对比计算，用专业的制图和数据分析软件OriginPro 8．0画出配送路径图．结果表明，对连接点选择进行优化的节约算法不仅避免了路线交叉，且计算结果优于传统节约法．%In order to study the saving algorithm in the application of vehicle routing problem , the paper analyzed the instance data of traditional savings algorithm and improved saving segmentation algorithm .Under the CW algorithm for the case , saving segmentation algorithm actually increases the distribution mileage and route crossed is not improved when the number of transport vehicles have been optimized to allow the distribution , so saving segmentation algorithm is no longer applicable .In this paper , the connection point selection saving algo-rithm approach to solving this problem .The calculation of specific examples was compared by matlab 7.0 and the distribution route map was drawn by a professional graphics and data analysis software OriginPro 8.0.The results show that the connection point selection saving algorithm can not only avoid the route cross , but also optimize the calculation results .
Li, Rui; Lim, Annabelle; Alonso, Sylvie
2011-01-01
Whereas the great majority of the current vaccines are delivered through the parenteral route, mucosal administration has been increasingly considered for controlling infection and preventing disease. Mucosal vaccination can trigger both humoral and cell-mediated protection, not only at the targeted mucosal surface, but also systemically. In this regard, nasal vaccination has shown great potential. The live attenuated strain of Bordetella pertussis, BPZE1, is particularly attractive and promising as a nasal vaccine delivery vector of heterologous antigen vaccine candidates. BPZE1 was originally developed as a live nasal pertussis vaccine candidate, and is currently undergoing phase I clinical trial in human (http://www.child-innovac.org). Highly adapted to the human respiratory tract and offering several potential protein carriers for presentation of the heterologous antigen vaccine candidates, BPZE1 represents an appealing platform for the development of live recombinant vaccines delivered via the nasal route that would confer simultaneous protection against pertussis and the targeted infectious disease(s).
Institute of Scientific and Technical Information of China (English)
陆琳; 谭清美
2006-01-01
针对一类随机需求车辆路径问题(stochastic vehicle routing problem,SVRP),结合现实生活中长期客户服务记录所隐含的统计性知识构建新的统计学模型,并将种群搜索与轨迹搜索算法相结合提出了一种新的混合粒子群优化算法.该算法通过引入导引式局部搜索,来减小粒子群搜索陷入局优的可能性以获得更优化解.仿真计算证明混合粒子群优化算法的有效性.同时,该算法也拓展了VRP的算法空间.
车辆路径问题的模拟退火算法%Simulated Annealing Algorithm for Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
胡大伟; 朱志强; 胡勇
2006-01-01
在构造车辆路径问题(Vehicle Routing Problem,VRP)数学模型后,采用路径间调整和路径内优化方法,结合模拟退火算法策略对该问题进行求解.重点阐述了VRP模拟退火算法的设计思路,详细分析和编制了求解程序框图,并实现了计算机求解.仿真测试结果表明:采用模拟退火算法求解VRP效果显著,计算速度较快,与有关算法对比显示了较强的实用性和可操作性,为解决大规模VRP提供了一种有效算法.
车辆路径安排问题算法研究综述%Algorithmic Review on the Vehicle Routing Problem
Institute of Scientific and Technical Information of China (English)
陈文兰; 戴树贵
2007-01-01
车辆路径安排是决定物流配送费用的主要因素.车辆路径安排问题(Vehicle Routing Problem,VRP)是近年来应用数学、计算机科学和物流科学研究的一个热点问题,产生了众多的研究成果.本文首先讨论了VRP的分类,然后基于VRP算法构造方法的分类,概要介绍了近五年来VRP算法研究的主要成果,并对研究方法进行了分析,最后对全文进行了总结,并探讨了该问题未来的研究方法.
VMI&TPL供应链下的VRP问题研究%Vehicle Routing Problem in Integrated Supply Chain of VMI and TPL
Institute of Scientific and Technical Information of China (English)
汤中明
2013-01-01
Based on the background of supply chain which integrates VMI and TPL, a new vehicle routing problem model is built. The model proposes a supply chain network which contains many vendors, one TPL and one manufacture, and TPL is responsible for the decision of vehicle routing problem. The solution strategy is divided into two courses. Firstly, basic data of Travelling Salesman Problem (TSP) is built by saving algorithm. Secondly, based on the basic data of TSP, a VRP model is built and solved by simulation annealing genetic algorithm. At last, the algorithm and its effectiveness are explained by a numerical example.%提出供应商管理库存(VMI)与第三方物流(TPL)集成供应链管理模式,构建VMI&TPL模式下的VRP优化模型.模型考虑“多供应商,单TPL,单制造商”的供应链网络,TPL负责统一为所有供应商配送货物.为提高求解效率,将求解过程分为两个部分:TPL首先基于节约法建立旅行商问题(TSP)基础数据,然后通过调用TSP基础数据来安排车辆分配与路线计划.VRP模型采用模拟退火遗传算法进行求解,通过算例对模型的求解策略及其有效性进行了说明.
物流配送车辆调度问题算法综述%Research on Algorithm of Delivery Vehicle Routing Problems
Institute of Scientific and Technical Information of China (English)
陈君兰; 叶春明
2012-01-01
Delivery vehicle routing problems （VRP） is a kind of optimization problems, aiming at solving the vehicle routing problems in delivery section. And they have been a focus of research in logistics control optimization recently. After summarize different kinds of VRP, the article gives the relevant general models. The character and the application of genetic algorithm, simulated annealing, tabu search, ant colony algorithm, particle swarm optimization are analyzed and the current possibilities to solve VRP are also discussed. Finally, the development of VRP solution is presented, and point out that improved combined algorithm as well as new algorithm will be important measures to solve VRP.%配送车辆调度优化问题旨在解决配送中路径和车辆调度问题的一类组合优化问题，是近年来物流控制优化领域的研究热点。文章对运输调度问题进行了分类总结，给出总体模型的概括描述，分析遗传算法、模拟退火算法、禁忌搜索算法、蚁群算法和微粒群算法的特点及其在求解配送车辆调度优化问题中的求解思路，并讨论了其求解现状，对未来研究方向进行展望，指出改进混合现有算法，开拓新算法将是更有效解决配送车辆调度问题的好方法。
Jisheng Zhang; Limin Jia; Shuyun Niu; Fan Zhang; Lu Tong; Xuesong Zhou
2015-01-01
It is essential for transportation management centers to equip and manage a network of fixed and mobile sensors in order to quickly detect traffic incidents and further monitor the related impact areas, especially for high-impact accidents with dramatic traffic congestion propagation. As emerging small Unmanned Aerial Vehicles (UAVs) start to have a more flexible regulation environment, it is critically important to fully explore the potential for of using UAVs for monitoring recurring and no...
Minimum Makespan Multi-vehicle Dial-a-Ride
DEFF Research Database (Denmark)
Gørtz, Inge Li; Nagarajan, Viswanath; Ravi, R.
2009-01-01
-a-Ride problem, there are q vehicles each having capacity k and where each vehicle j ∈ [q] has its own depot-vertex rj ∈ V. A feasible schedule consists of a capacitated route for each vehicle (where vehicle j originates and ends at its depot rj) that together move all objects from their sources to destinations....... The objective is to find a feasible schedule that minimizes the maximum completion time (i.e. makespan) of vehicles, where the completion time of vehicle j is the time when it returns to its depot rj at the end of its route. We consider the preemptive version of multi-vehicle Dial-a-Ride, where an object may......Dial-a-Ride problems consist of a set V of n vertices in a metric space (denoting travel time between vertices) and a set of m objects represented as source-destination pairs {(si,ti)}mi=1, where each object requires to be moved from its source to destination vertex. In the multi-vehicle Dial...
Conductive two-dimensional titanium carbide `clay' with high volumetric capacitance
Ghidiu, Michael; Lukatskaya, Maria R.; Zhao, Meng-Qiang; Gogotsi, Yury; Barsoum, Michel W.
2014-12-01
Safe and powerful energy storage devices are becoming increasingly important. Charging times of seconds to minutes, with power densities exceeding those of batteries, can in principle be provided by electrochemical capacitors--in particular, pseudocapacitors. Recent research has focused mainly on improving the gravimetric performance of the electrodes of such systems, but for portable electronics and vehicles volume is at a premium. The best volumetric capacitances of carbon-based electrodes are around 300 farads per cubic centimetre; hydrated ruthenium oxide can reach capacitances of 1,000 to 1,500 farads per cubic centimetre with great cyclability, but only in thin films. Recently, electrodes made of two-dimensional titanium carbide (Ti3C2, a member of the `MXene' family), produced by etching aluminium from titanium aluminium carbide (Ti3AlC2, a `MAX' phase) in concentrated hydrofluoric acid, have been shown to have volumetric capacitances of over 300 farads per cubic centimetre. Here we report a method of producing this material using a solution of lithium fluoride and hydrochloric acid. The resulting hydrophilic material swells in volume when hydrated, and can be shaped like clay and dried into a highly conductive solid or rolled into films tens of micrometres thick. Additive-free films of this titanium carbide `clay' have volumetric capacitances of up to 900 farads per cubic centimetre, with excellent cyclability and rate performances. This capacitance is almost twice that of our previous report, and our synthetic method also offers a much faster route to film production as well as the avoidance of handling hazardous concentrated hydrofluoric acid.
Conductive two-dimensional titanium carbide 'clay' with high volumetric capacitance.
Ghidiu, Michael; Lukatskaya, Maria R; Zhao, Meng-Qiang; Gogotsi, Yury; Barsoum, Michel W
2014-12-04
Safe and powerful energy storage devices are becoming increasingly important. Charging times of seconds to minutes, with power densities exceeding those of batteries, can in principle be provided by electrochemical capacitors--in particular, pseudocapacitors. Recent research has focused mainly on improving the gravimetric performance of the electrodes of such systems, but for portable electronics and vehicles volume is at a premium. The best volumetric capacitances of carbon-based electrodes are around 300 farads per cubic centimetre; hydrated ruthenium oxide can reach capacitances of 1,000 to 1,500 farads per cubic centimetre with great cyclability, but only in thin films. Recently, electrodes made of two-dimensional titanium carbide (Ti3C2, a member of the 'MXene' family), produced by etching aluminium from titanium aluminium carbide (Ti3AlC2, a 'MAX' phase) in concentrated hydrofluoric acid, have been shown to have volumetric capacitances of over 300 farads per cubic centimetre. Here we report a method of producing this material using a solution of lithium fluoride and hydrochloric acid. The resulting hydrophilic material swells in volume when hydrated, and can be shaped like clay and dried into a highly conductive solid or rolled into films tens of micrometres thick. Additive-free films of this titanium carbide 'clay' have volumetric capacitances of up to 900 farads per cubic centimetre, with excellent cyclability and rate performances. This capacitance is almost twice that of our previous report, and our synthetic method also offers a much faster route to film production as well as the avoidance of handling hazardous concentrated hydrofluoric acid.
物流配送车辆路径的优化方法分析%Analysis on Optimizing Methods of Logistics Distribution Vehicles Routing Problem
Institute of Scientific and Technical Information of China (English)
张志强
2013-01-01
随着经济全球化的不断发展，各区域的经济交流不断加强，物流行业迅速发展起来，同时配送成本在物流行业发展过程中显得越来越重要。物流企业要想在激烈的社会竞争中不被淘汰，就必须考虑如何降低随着社会结构改变而出现复杂化的物流配送成本，不断提高自身的综合竞争力。文中主要介绍了有关计算和改进物流配送车辆路径优化方面的问题，着重论述了对蚁群算法在降低物流配送成本，以及物流配送车辆在路径优化上中的应用，从而选择出对配送车辆路径进行最好的优化的方法。%With the continuing development of economic globalization and increasingly closer link between regional economies,the logistics industry grows with a high speed.The cost on distribution is thus,being attached more and more attention in the development of logistics industry.The issues on how to reduce the more complicated cost of distribution as the social structure is undertaking profound changes and how to improve their overall strength must be taken into account by the logistics enterprises in order not to be eliminated in the fierce competition.The paper introduced algorithms and methods for optimizing logistics distribution vehicles routing problem.Ant Colony Algorithm (ACA)was given particular attention to illustrate its role in reducing distribution cost and optimizing the routing problem so as to select the best method for the routing of distribution vehicles.
Institute of Scientific and Technical Information of China (English)
刘家利; 马祖军
2013-01-01
To solve the insufficiency of transportation capacity in a company and the imbalance of transportation capacity among its decentralized distribution centers in each decision-making process, this study developed a mixed-integer programming model for multi-depot open vehicle routing problem (VRP) with time windows based on vehicle leasing and sharing. By introducing a virtual distribution center, the multi-depot VRP was transformed into a single depot VRP. Then a hybrid genetic algorithm was proposed by combing scanning algorithms with C-W saving algorithm, as well as optimizing vehicle routing and vehicle scheduling together. Finally, the validity of the model and algorithm was demonstrated by the real data from logistics branch of Chongqing Tianyou Dairy Co., Ltd. The results show that the model and algorithm performs better than company's existing solution in the following aspects: total travel mileage, total cost, and time en route of delivery vehicles. In addition, the sensitivity analysis of model parameters and the convergence analysis of the algorithm were done, and the results show that the algorithm has better performance.%针对企业自身运力有限以及旗下多个配送中心在各决策周期运力不均衡的情况,提出了一类具有多个配送中心、需要进行车辆租赁和车辆共享、有时间窗限制、开环的VRP,建立了相应的混合整数规划模型.通过引入一个虚拟配送中心,将多配送中心VRP转化为单配送中心VRP,并设计了一种结合扫描算法和C-W节约算法、对车辆路径和车辆调度统筹优化的混合遗传算法.最后,以重庆天友乳业物流分公司的业务数据对该模型的可行性和有效性进行了验证,结果表明本文所提方法与该企业现有的配送方案相比,在配送总里程、配送总成本和车辆在途时间等方面均有明显改进.此外,进行了模型参数的灵敏度分析和算法的收敛性分析,结果表明该算法具有较好的性能.
Routing and scheduling problems
DEFF Research Database (Denmark)
Reinhardt, Line Blander
In today’s globalized society, transport contributes to our daily life in many different ways. The production of the parts for a shelf ready product may take place on several continents and our travel between home and work, vacation travel and business trips has increased in distance the last......, the effectiveness of the network is of importance aiming at satisfying as many costumer demands as possible at a low cost. Routing represent a path between locations such as an origin and destination for the object routed. Sometimes routing has a time dimension as well as the physical paths. This may...... to a destination on a predefined network, the routing and scheduling of vessels in a liner shipping network given a demand forecast to be covered, the routing of manpower and vehicles transporting disabled passengers in an airport and the vehicle routing with time windows where one version studied includes edge...
Multicriteria Network Routing of Tactical Aircraft in a Threat Radar Environment
1991-03-01
Vehicle Routing Problem and the multicriteria optimization package ADBASE. This...mathematical programming, the vehicle routing problem is essential to the development of complete routes of ingress and egress. The vehicle routing problem provides...formulation of the vehicle routing problem is structured 23 as follows: The objective function minimizes the distance cost. The first constraint ensures
Routing Service Quality—Local Driver Behavior Versus Routing Services
DEFF Research Database (Denmark)
Ceikute, Vaida; Jensen, Christian S.
2013-01-01
experiments with real vehicle trajectory data and an existing online navigation service. It is found that the availability of information about previous trips enables better prediction of route travel time and makes it possible to provide the users with more popular routes than does a conventional navigation...... of the quality of one kind of location-based service, namely routing services. Specifically, the paper presents a framework that enables the comparison of the routes provided by routing services with the actual driving behaviors of local drivers. Comparisons include route length, travel time, and also route...
Minimum Makespan Multi-Vehicle Dial-a-Ride
DEFF Research Database (Denmark)
Gørtz, Inge Li; Nagarajan, Viswanath; Ravi, R.
2015-01-01
Dial-a-Ride problem, there are q vehicles, each having capacity k and where each vehicle j epsilon [q] has its own depot-vertex r(j) epsilon V. A feasible schedule consists of a capacitated route for each vehicle (where vehicle j originates and ends at its depot r(j)) that together move all objects...... from their sources to destinations. The objective is to find a feasible schedule that minimizes the maximum completion time (i.e., makespan) of vehicles, where the completion time of vehicle j is the time when it returns to its depot r(j) at the end of its route. We study the preemptive version......Dial-a-Ride problems consist of a set V of n vertices in a metric space (denoting travel time between vertices) and a set of m objects represented as source-destination pairs {(s(i), t(i))}(i-1)(m), where each object requires to be moved from its source to destination vertex. In the multi-vehicle...
Institute of Scientific and Technical Information of China (English)
吴聪; 杨建辉
2015-01-01
Vehicle routing scheduling is an important factor to improve the operation efficiency of logistics enterprises, to solve the defects of the standard particle swarm optimization algorithm, an improved particle swarm optimization algorithm for vehicle routing problem of logistics distribution is proposed. Firstly, the mathematical model for vehicle routing problem of logistics distribution is established, and then the vehicle and vehicle routing are encoded into particles, the optimal scheme for vehicle routing problem of logistics distribution is found by the collaboration between particles in which de-fects of the particle swarm algorithm are improved, finally the simulation experiment is used to test the performance. The results show that the proposed algorithm not only accelerates the solving speed, but also increases the obtaining the optimal solution probability or vehicle routing problem of logistics distribution problem, and has some advantages than other scheduling algorithms.%车辆优化调度是提高物流企业运营效益的重要因素，针对标准粒子群优化算法存在的不足，提出一种改进粒子群算法（IPSO）的物流配送车辆调度优化方法。建立物流配送车辆调度优化的数学模型，将车辆与车辆路径编码成粒子，通过粒子之间的协作找到最优物流配送车辆调度优化方案，并对粒子群算法存在的不足进行了相应的改进，最后给出仿真实验对其性能进行测试。实验结果表明，IPSO算法不仅加快了物流配送车辆调度优化问题求解的速度，而且获得了最优解的概率，具有比其他调度算法更明显的优势。
Model multivehicle routing dengan persaingan pasar
2011-01-01
Multiple vehicle routing problem has potential real-word applications as it enables the study of strategic competition among private trucking companies in such ar- eas as the transportation of aggregates to construction sites. The multiple vehicle routing problem with profits and competition (MVRPPC) represents an extension of the vehicle routing problem in that it: incorporates competition into the routing process, maximizes profits rather than minimizes costs, and assumes that truc...
节点具有双重需求的车辆路径问题及其性质%THE VEHICLE ROUTING PROBLEM AND IT'S PROPERTY WITH NODES HAVING DOUBLE DEMANDS
Institute of Scientific and Technical Information of China (English)
王科峰; 叶春明; 唐国春
2011-01-01
Based on the original definition of the Simultaneous Pickup and Delivery Vehicle Routing Problem, the relationship between the vehicle's capacity and the demand of the node was expanded into the case that the later was permitted to be greater than the former. Then the reducibility of the Simultaneous Pickup and Delivery Vehicle Routing Problem and the Split Vehicle Routing Problem with Pickup and Delivery was studied. The reducibility definitions of these two problems were given. It follows that when the distance satisfies the triangle inequality and the vehicle's capacity is equal to 1, the Split Vehicle Routing Problem with Pickup and Delivery is reducible and equivalent to the Simultaneous Pickup and Delivery Vehicle Routing Problem, and that when the vehicle's capacity is greater than or equal to 2, these two problems were irreducible. Then the complexity of these two problems is proved when the vehicle's capacity was equal to 1 and greater than or equal to 3. Finally an example shows the obvious structural difference of the optimal solutions between the Split Vehicle Routing Problem with Pickup and Delivery and the Split Vehicle Routing Problem.%在原有同时收发车辆路径问题定义的基础上,将节点需求与车辆容量的关系拓展到允许节点需求大于车辆容量的情形.接着对集送货需求可拆分车辆路径问题和同时收发车辆路径问题的可简化性进行了研究.给出了两类问题可简化的定义,并得到了当距离满足三角不等式,车辆容量为1时集送货需求可拆分车辆路径问题可简化并与同时收发车辆路径问题等价,而当容量大于等于2时两类问题都不可以简化的结论.同时也对两类问题当车辆容量等于1时,以及大于等于3时的计算复杂性给出了证明.最后通过一个实例说明了集送货需求可拆分车辆路径问题与同时收发车辆路径问题在最优解的结构性质方面存在着明显差异.
Institute of Scientific and Technical Information of China (English)
满飞宇; 陈云鹤
2011-01-01
目前国内外对随机需求多车辆路径问题的研究还很少,本文针对标准hopfield神经网络容易陷入局部极值点等问题,以总路程最短和总使用车辆数最少为目标,提出了一种基于退火策略的混沌神经网络的求解随机需求多车辆路径问题的算法,该算法既可以使混沌运动有足够长的进程以提高粗搜索性能,又可以随混沌动态的减弱使收敛速度加快。实验结果表明,该算法优化车辆路径更佳,是解决随机需求多车辆路径问题的有效方法。%In recent times,the research of multiple vehicles routing problem（VRP） with stochastic demand is not consummate in domestic and abroad.However,this paper indicates a kind of annealing chaotic neural network to multiple vehicles routing problem with stochastic demand,targeting to the shortest total distance and the least number of vehicles,while standard Hopfield neural network easy to fall into local optimum.In this algorithm,chaos lasts long enough to improve the search performance of crude,and also convergence rate is larger while chaotic dynamics weakens.According to the experimental results,vehicle routing is better using this algorithm,the algorithm is a effective method to solving multiple vehicles routing problem with stochastic demand.
Institute of Scientific and Technical Information of China (English)
汤雅连; 蔡延光; 郭栋; 郭帅
2013-01-01
This paper introduces the principle and essential procedures of Electromagnetism -like Mechanism Algorithm. Since time varying can affect the efficiency of Vehicle Routing Problem , a kind of mathematical model of TVTVRP(Time Varying In-cident Vehicle Routing Problem) is built, and then this algorithm is applied to single -depot and single-vehicle-type Incident Vehicle Routing Problem.Meanwhile, Genetic Algorithm and Ant Colony Algorithm are also applied to the same model too .The results show that EMA is flexible to solve IVRP, and it is better than the other two algorithms during the optimization process .And the simulation results show that the algorithm, which has simple characters, optimization efficiency and strong robustness etc ., is a powerful tech-nique to solve this kind of problems .% 介绍了基本的类电磁机制算法的原理并对其进行改进，由于时变影响运输调度的效率，建立了一种时变关联物流运输调度问题（Time Varying Incident Vehicle Routing Problem ， TVIVRP）的数学模型，并用改进的算法来对单车场单车型的关联物流运输调度问题求解，然后与遗传算法（Genetic Algorithm， GA）和蚁群算法（Ant Colony Algorithm， ACA）求解此模型的结果相比较。实例证明该算法求解关联运输调度问题是可行的，并优于传统的遗传算法和蚁群算法，而且具有实现简单、优化效率高、鲁棒性强等特点。
基于树形结构的铁路车流径路优化模型%Optimization Model of Railway Vehicle Flow Routing Based on Tree Form
Institute of Scientific and Technical Information of China (English)
温旭红; 林柏梁; 陈雷
2016-01-01
铁路车流具有独特的运行特征,在铁路支点路网上车流的运行径路具有树形结构.本文基于该特点提出一个基于树形结构的铁路车流径路优化改进模型.模型以路网上车流的广义里程成本最小化为目标,以车流径路的树形结构约束、车流强度守恒以及路段通过能力限制等为约束条件,并且在MATLAB平台上用IBM ILOG CPLEX软件对模型进行求解.通过与已有的车流径路优化模型进行对比,验证了模型的有效性.%Railway vehicle flow routing ,which is required to have a tree form structure for each destination ,fea-tures unique operating characteristics .A0-1 mixed integer programming model of railway vehicle flow routing problem was proposed based on the tree form structure .With the minimum total cost of railway vehicle flow assigning as the optimization goal ,the tree form of route ,conservation of railway vehicle flow and capacity lim-it as constraint conditions ,the model was validated on the MATLAB platform invoking IBM ILOG CPLEX op-timizer with simulated data .The effectiveness of the model was verified through comparison with existing vehi-cle flow routing optimization models .
Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R
2014-05-27
A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.
Institute of Scientific and Technical Information of China (English)
王科峰; 叶春明
2013-01-01
A general outline of various types of vehicle routing problems in the field of reverse logistics was given.The vehicle routing problems were divided into two classes,i.e.the problem of single demand and double demands,according to the demand characteristic of the customer node.The vehicle routing problem with simultaneous delivery and pickup (VRPSDP) and the vehicle routing problem with split deliveries and pickups (SVRPPD) were called as the vehicle routing problem with nodes of double demands (VRPNDD).Their definitions and mathematic models were given.Then as the preliminary work for designing the heuristics,some constitutive properties of the solution for the VRPNDD were investigated.The difference in properties of optimal solutions between SVRPPD and SDVRP (the vehicle routing problem with split delivery) was illustrated,and a theorem was proved to show the significance of the heuristics' improving on cost saving analysis of SVRPPD relative to VRPSDP.%概括介绍了逆向物流领域中的各类车辆路径问题,将问题按照节点的需求类型分为节点单需求以及具有双重需求两个大类.按照节点的需求类型,将同时送取货(VRPSDP)、集送货需求可拆分车辆路径问题(SVRPPD)统称为节点具有双重需求车辆路径问题(VRPNDD).文中首先给出了它们的定义及数学模型.接着,作为设计求解问题启发式算法的前期工作,对VRPNDD问题解的结构方面的一些性质进行了分析证明.最后,举例说明了SVRPPD与送货需求可拆分车辆路径问题最优解性质方面的差异,并通过定理证明说明了SVRPPD,VRPSDP启发式算法的改良对于SVRPPD相对VRPSDP节省成本百分比研究的意义.
Reviews on Vehicle Routing Problem and Its Solution Methods%车辆路径规划问题及其求解方法研究进展
Institute of Scientific and Technical Information of China (English)
孙丽君; 胡祥培; 王征
2006-01-01
对车辆路径规划问题(Vehicle Routing Problem, VRP)领域的研究进行综述,根据目前的研究状况对该问题进行分类;分析该问题的图模型和数学模型两大类模型各自的优缺点;分四大类讨论求解该问题的算法:精确算法(exact algorithm),构造启发式算法(constructive heuristic algorithm),改进启发式算法(improving heuristic algorithm),和亚启发式算法(meta-heuristic algorithm),评述各类算法适用的问题求解阶段以及各自的优缺点;探讨国内在VRP领域的研究成果.在此基础上,对求解该问题的方法进一步的研究方向做了展望.
计重收费政策下的货物权重车辆路径%Weighted vehicle routeing problem under toll-by-weight policy
Institute of Scientific and Technical Information of China (English)
吴思; 丁以中
2010-01-01
为提高物流效率、降低物流成本,在货物权重车辆路径问题(Weighted Vehicle Routeing Problem,WVRP)和计重收费问题研究的基础上,按照完全计重收费模式,建立以运输过程中总费用(包括固定费用、油耗费用和路桥费用)最小为目标函数的整数非线性规划优化模型.对实际算例,首先使用lingo软件求解精确解,然后利用粒子群优化(Particle Swarm Optimization,PSO)算法求解近似优化解,最后求解一般车辆路径问题模型并计算出相应的行驶总费用.3种结果的比较分析说明所提出的模型和用PSO算法求解的可行性和有效性.该模型可实现运输资源的优化配置,降低企业的物流成本.
Taboo search algorithm of split delivery vehicle routing problem%需求可拆分车辆路径问题的禁忌搜索算法
Institute of Scientific and Technical Information of China (English)
孟凡超; 陆志强; 孙小明
2010-01-01
为解决实际配送运输中的车辆路径问题(Vehicle Routing Problem,VRP),通过改进传统的数学模型,解除每个客户需求只能由1辆车配送的约束,建立改进的可拆分车辆路径问题(SplitDelivery VRP,SDVRP)数学模型,并利用禁忌搜索算法(Taboo Search Algorithm,TSA)进行求解.在TSA的设计中,根据SDVRP模型的特点对初始解、邻域搜索和解的评价等进行特殊处理.算例表明,该模型不仅可以解决VRP模型中不允许配送点需求量超出装载量的限制,而且通过相应配送点需求量的拆分和重新组合,可节省车辆数目、缩短路线长度、提高车辆装载率.
一类随机顾客车辆路径问题及其算法%Stochastic Customer Vehicle Routing Problem and Its Algorithm Analysis
Institute of Scientific and Technical Information of China (English)
陆琳; 蔡绍洪
2010-01-01
针对一类随机顾客车辆路径问题(Vehicle routing problem with stochastic customer,VRPSC),探讨了VRPSC的实时动态规划机制,并结合运送货物需求量的不同特性,分析了车辆供货中遇到服务路线失败时的两种不同服务策略并构建了相应的模型.设计了针对VRPSC的蚁群算法,并选用60个节点的基准问题对VRPSC的动态模型进行了仿真计算.结果表明,对顾客信息进行数据挖掘以获取较精确经验概率以及采用部分服务策略均有助于缩短车辆总行驶路径,为有效降低车辆的运行成本提供了科学依据.
Optimization of Logistic Distribution Center Location and Vehicle Routing Problem%配送中心选址与车辆路径问题的优化
Institute of Scientific and Technical Information of China (English)
汤雅连
2014-01-01
为了克服蚁群算法(Ant Colony Optimization,ACO)搜索初期信息匮乏、信息素累积时间长、求解速度慢的缺点,结合具有快速全局搜索能力的遗传算法(genetic algorithm,GA),同时引入混沌搜索和平滑机制,采用混沌搜索产生初始种群可以克服生成大量非可行解的缺陷,加速染色体向最优解收敛,平滑机制有助于对搜索空间进行更有效的搜索,构成混沌蚁群优化算法(Chaos Ant Colony Optimization,CACO).建立物流配送中心选址(logistic distribution center location)与车辆路径问题(vehicle routing problem,VRP)的数学模型,分别应用CACO和GA求解,对50客户规模的问题模型仿真,结果表明CACO优于GA.
空车配货VRP问题的路径匹配算法%Path-Matching Algorithm for Vehicle Routing Problem of Freight Load Matching
Institute of Scientific and Technical Information of China (English)
翟泳; 刘杰华; 张伟; 樊铭渠
2008-01-01
针对现有VRP(Vehicle routing problem)问题的精确解法和启发式算法应用于空车配货信息检索时的局限,引入图的概念,提出了一个基于交通路网的路径匹配算法,给出了算法复杂度分析.该算法利用交通路网中各结点之间的距离关系,检索给定起讫点间及起讫点与各自邻近结点群之间存在的配货信息,同时规划出收益费用比最优的行驶路径,并能根据配货行驶路径的特点对检索出的所信息进行分析、评价和优选,以方便空车配货组织.最后用一个仿真实例验证算法的有效性.
车载导航系统的市场渗透率仿真研究%Simulation on Route Guidance Benefit of In-Vehicle Navigation System
Institute of Scientific and Technical Information of China (English)
杨珍珍; 干宏程
2012-01-01
In-vehicle navigation system (1VNS) usually provides real-time traffic information to assist drivers to choose optimal routes. To explore the route guidance effect of IVNS' s market penetration rate to freeway networks, including traffic benefit and environment benefit, this paper uses macroscopic dynamic traffic network model to develop a simulation platform. It uses dynamic traffic assignment model to describe route guidance mechanism of the IVNS and adopts total waiting time and total time spend as traffic benefit indicator. The VT-Micro model is used to measure vehicle emissions and fuel consumption. Moreover, the study calculates the direct economic benefits in terms of air pollutant treatment cost saving and fuel consumption. Taking a network with two origins and two destinations as an example, the simulation shows that the IVNS can effectively equilibrium freeway network' s demand, improve freeway network efficiency, reduce mobile source emissions and create huge economic benefits. Market penetration rate is recommended to value from 0. 2 to 0. 3 in view of traffic benefits and environment benefits. This simulation system iseffective for designing and evaluating the IVNS. It also provides the basis for decision-making and references for relevant departments to improve the operational efficiency of traffic networks.%车载导航系统(IVNS)能提供实时有效交通信息辅助驾驶人选择最佳路径.为了探讨IVNS的市场渗透率对路网运行效益(交通效益和环境效益两方面)的影响,本文运用宏观动态交通网络模型METANET建立仿真平台,用反馈式动态交通分配模型描述IVNS路径诱导下驾驶人的行为,以总排队时间和总耗费时间作为交通效益评价指标,用反映速度—加速度关系的机动车排放和燃油消耗关系模型——VT-Micro模型计算机动车排放量和燃油消耗量,并用货币价值量化排放减少带来的直接经济效益(包括大气污染治理费用和燃油
A Study Issues Related To Improve Route Stability In AODY Routing Protocol In VANET
Directory of Open Access Journals (Sweden)
Annu Mor
2013-01-01
Full Text Available Vehicular Ad Hoc Network (VANET is a sub class of mobile ad hoc networks. VANET provides wireless communication among vehicles and vehicle to road side equipments, according to IEEE 802.11 p standard for end to end communication between vehicles . For end to end communication between vehicles a routing protocols is used to find a route based on link properties. One of the most important routing protocols used in ad hoc networks is AODV. This protocol is connectivity based reactive protocol that searches routes only when they are needed. It always exchanges control packets between neighbor nodes for routing. In this article author present cross layer technique that find channel security at link layer to AODV routing protocol to improve the communication in vehicles for safety purpose. To eliminate route discovery routers, propose PAODV as routing protocol. It improves AODV control overhead and makes routes more stable.
Ant Colony Algorithm Based on Vehicle Routing Problem with Time Windows%基于带时间窗的车辆路径问题的蚁群算法
Institute of Scientific and Technical Information of China (English)
叶仲泉; 王书勤; 黄茜
2007-01-01
针对带时间窗车辆路径问题(Vehicle Routing Problem with Time Windows, VRPTW)的特点,对蚁群算法进行了改进, 优化了其搜索解的能力和收敛速度,用实例证明了改进的蚁群算法对解决VRPTW的有效性.
The Improved Saving Methods of Vehicle Routing Problem with Time Window%带时间窗约束的多类型车辆路径问题的改进节约算法
Institute of Scientific and Technical Information of China (English)
陈锋
2012-01-01
研究了带时间窗约束的多类型车辆路径问题.通过对C-W节约算法进行修正得来的改进型节约算法,应用于多类型车辆路径问题.通过具体算例说明了该算法的可行性.改进的基于邻域搜索的节约算法用于解决更贴合现实生活的带时间窗约束的多类型车辆路径问题,并通过计算机编程实现了该算法.通过算例证实,运用该程序我们能够快速建立多类型车辆路径问题的满意调度方案.%The multi-type vehicle routing problem with time window is investigated. By modifing the C-W algorithm, improved saving algorithm has applied to the multiple-type vehicle routing problem. And the specific and numerical algorithm example shows that the improved saving algorithm is feasible. This algorithm based on neighbourhood search can practically solve the multi-type vehicle routing problem, and achieved by computer programming. This computer programming could be used to produce the satisfied dispatching project rapidly from the multi-type vehicle routing problem this paper mentioned, which are proved by the improved saving algorithm.
2010-10-01
... public entities operating fixed route systems. 37.73 Section 37.73 Transportation Office of the Secretary... operating fixed route systems. (a) Except as provided elsewhere in this section, each public entity operating a fixed route system purchasing or leasing, after August 25, 1990, a used bus or other...
2010-10-01
... public entities operating fixed route systems. 37.71 Section 37.71 Transportation Office of the Secretary... operating fixed route systems. (a) Except as provided elsewhere in this section, each public entity operating a fixed route system making a solicitation after August 25, 1990, to purchase or lease a new...
Improved time window based conflict-free automated guided vehicle system routing%基于改进时间窗的AGVs避碰路径规划
Institute of Scientific and Technical Information of China (English)
乔岩; 钱晓明; 楼佩煌
2012-01-01
针对柔性制造系统中的自动导引车在动态不稳定环境下不能按照时间窗规划好的既定路径运行的问题，提出通过实时改变自动导引车通过节点的优先级，调整相应节点的自动导引车的通过顺序来更新自动导引车运行路径，对时间窗算法进行改进，从而实现多自动导引车动态环境下的路径规划。以含有8台自动导引车的淋雨线系统为应用案例进行仿真实验，对改进前的时间窗算法和改进后的时间窗算法进行对比，说明了算法的实现过程。通过仿真证明了该算法能减少冲突数目，有效实现多自动导引车避碰，具有更好的鲁棒性和柔性，同时能够提高系统效率。%In flexible manufacturing system, Automated Guided Vehicles(AGV)could not operate in planned routes of time window under dynamic uncertain environment. Aiming at this problem, the updating AGV operating pass was proposed by changing the priority of AGV passing through the nodes and adjusting the passing sequences of corresponding nodes. Meanwhile, time-window algorithm was improved to realize multiple AGV route planning in dynamic environment. In simulation experiment, rain line system with eight AGV was used to compare the unimproved time-window algorithm with the improved time-window algorithm, and the realization process of the algorithms was illustrated. Through the simulation, the proposed algorithm was proved to have better robustness and flexibility, and could reduce the number of conflicts, realize conflict-free effectively and improve system efficiency.
变路网情况下车辆路径问题建模及应用%Model and Application of Vehicle Routing Problem with Variable Network Structure
Institute of Scientific and Technical Information of China (English)
陈森; 李孟军; 李本先; 王鹏
2012-01-01
Initiated by the need of vehicle routing problem in reality, this article presented a non-deterministic vehicle routing problem with variable network structure. The impact derived from variable network structure was discussed. Combining the road network and vehicle routing, a combinatorial optimization model was developed. An improved genetic algorithm and random recursion heuristics were designed to solve this problem. As an application and a demonstration of our results, a numerical example was presented to highlight the significance of the proposed model as well as the efficacy of the proposed algorithm.%受车辆调度中的一类现实需求启发,提出了路网结构可变情况下的车辆路径问题.探讨了路网变动对车辆路径的影响,在描述可变路网的基础上,基于路网、路径双层优化思想,建立了问题优化模型.考虑到路网变化给问题求解带来的复杂性,给出了改进遗传算法与随机递归算法相结合的求解策略.作为模型的直接应用和说明,最后的算例验证了模型和算法的合理性、有效性.
基于蚁群算法的循环取货车辆路径优化%Problem on Vehicle Route Optimization of Milk-run Based on Ant Colony Algorithm
Institute of Scientific and Technical Information of China (English)
孙洋; 严伟
2015-01-01
In order to solve the problem on the vehicle routing optimization of milk-run to achieve the overall cost in the lowest In the process of milk-run.This paper constructs the model of vehicle routing optimization to solve the model by ant colony algorithm.The result shows that the ant colony algorithm can effectively solve the vehicle routing problem,and makes the cost of the whole process be the least.%文中以实现循环取货过程中整体费用最低为目标，通过构建车辆路径优化的模型，使用蚁群算法对模型进行求解，并与解决该类问题常用的遗传算法、粒子群算法进行比较分析。证明了蚁群算法能够有效的解决车辆路径优化问题，并使得循环取货过程的整体费用达到最低。
Applying Tabu Heuristic to Wind Influenced, Minimum Risk and Maximum Expected Coverage Routes
1997-02-01
31 111.3. GENERAL VEHICLE ROUTING PROBLEM .......................................................... 33...r. L3. Background The vehicle routing problem with maximum coverage is an extension of the classical general vehicle routing problem (GVRP). A general...review from the literature for the general vehicle routing problem includes Eilon et al. (1971) and Bodin (1983). Within a traditional deterministic
Optimization of Perishable Products in Incident Vehicle Route Problem%易腐产品运输调度问题的优化①
Institute of Scientific and Technical Information of China (English)
汤雅连; 蔡延光; 章云; 乐峰
2013-01-01
The perishable products go bad easily in transportational process and have the trait of timeliness and incident among goods. This paper proposed a mathematical model of Incident Vehicle Route Problem with Time Window (IVRPTW) to consider production distribution for perishable products.And adapt the Immune Clonal Selection Algorithm(ICSA) to solve this complex problem. On the basis of modeling and simulating examples of this problem, it is shown that the programming model and algorithm are reasonable and efficient.Experiment result also shows the immune clonal selection algorithm can find the optimal or nearly optimal solution effectively compared with the genetic algorithm.% 针对易腐产品在运输过程中容易变质，具有时效性和货物关联性的特点，构建一种带软时间窗的关联运输调度问题的数学模型来考虑易腐产品的配送，并采用免疫克隆选择算法求解这个复杂问题。通过对该问题进行分析建模和数值求解，说明了该模型和算法的合理性和有效性。与遗传算法相比较，免疫克隆选择算法能更有效地解决关联运输调度问题。
Institute of Scientific and Technical Information of China (English)
殷招伟; 戴文博; 钱俊彦
2015-01-01
The interdisciplinary application of intelligent transportation system comes into being just to meet people’s growing demand.The analysis of shortest path is the key problem in the application of VRGS (Vehicle Route Guidance System), the Dijkstra algorithm is the common algorithm to solve this problem effectively. Combined two-tree Dijkstra algorithm and multi-core and multi-threading technology, this paper optimizes and improves the traditional Dijkstra algorithm. And it discusses the application of the algorithm in VRGS.At last, this paper poves its practicality and efficiency by simulating the shortest path search process of Guilin.%为了满足人们日益增长的出行需求，跨学科的智能交通系统应运而生。最短路径分析是GIS车辆诱导系统应用的关键问题，Dijkstra 算法是解决该问题的常用算法。文章结合二树 Dijkstra 算法的思想和现代多核多线程的技术，对 Dijkstra算法进行了优化与改进，并对该算法在车辆诱导系统中的应用进行了探讨。该系统以桂林市为例模拟了最短路径搜过程，证明该算法的高效性和实用性。
The Vehicle Routing Problem with Split Demand and Its Research Progress%需求可拆分的车辆路径问题及其研究进展
Institute of Scientific and Technical Information of China (English)
李军; 张建勇; 张博
2016-01-01
Vehicle scheduling is the key of the transportation optimization, vehicle routing problem with split demand is an important branch, is more in line with the actual situation of vehicle delivery, and can better meet the actual needs of the enterprise management. This paper briefly introduces the vehicle routing problem with split demand, and then makes a detailed analysis of the domestic and foreign research progress.%车辆调度是运输环节优化的关键所在,可拆分车辆路径问题作为车辆路径问题的一个重要分支,具有更切合车辆配送的实际情况,更能满足企业经营管理的实际需求.本文首先对需求可拆分的车辆路径问题进行了简要介绍,然后对其国内外研究进展进行了详细分析.
VANET Routing Protocols: Pros and Cons
Paul, Bijan; Bikas, Md Abu Naser
2012-01-01
VANET (Vehicular Ad-hoc Network) is a new technology which has taken enormous attention in the recent years. Due to rapid topology changing and frequent disconnection makes it difficult to design an efficient routing protocol for routing data among vehicles, called V2V or vehicle to vehicle communication and vehicle to road side infrastructure, called V2I. The existing routing protocols for VANET are not efficient to meet every traffic scenarios. Thus design of an efficient routing protocol has taken significant attention. So, it is very necessary to identify the pros and cons of routing protocols which can be used for further improvement or development of any new routing protocol. This paper presents the pros and cons of VANET routing protocols for inter vehicle communication.
High bandwidth on-chip capacitive tuning of microtoroid resonators
Baker, Christopher G; McAuslan, David L; Sheridan, Eoin; Bowen, Warwick P
2016-01-01
We report on the design, fabrication and characterization of silica microtoroid based cavity opto-electromechanical systems (COEMS). Electrodes patterned onto the microtoroid resonators allow for rapid capacitive tuning of the optical whispering gallery mode resonances while maintaining their ultrahigh quality factor, enabling applications such as efficient radio to optical frequency conversion, optical routing and switching applications.
Membrane capacitive deionization
Biesheuvel, P.M.; Wal, van der A.
2010-01-01
Membrane capacitive deionization (MCDI) is an ion-removal process based on applying an electrical potential difference across an aqueous solution which flows in between oppositely placed porous electrodes, in front of which ion-exchange membranes are positioned. Due to the applied potential, ions ar
Steerable Capacitive Proximity Sensor
Jenstrom, Del T.; Mcconnell, Robert L.
1994-01-01
Steerable capacitive proximity sensor of "capaciflector" type based partly on sensing units described in GSC-13377 and GSC-13475. Position of maximum sensitivity adjusted without moving sensor. Voltage of each driven shield adjusted separately to concentrate sensing electric field more toward one side or other.
随机配送时间车辆路径问题的建模及算法%Model and Algorithm of Vehicle Routing Problem with StochasticTravel Time
Institute of Scientific and Technical Information of China (English)
刘昌生; 程敏; 孟祥先; 贺柯元
2013-01-01
Vehicle routing problem(VRP)is an important content of modern logistics and distribution management. choosing the proper distribution route would be accelerating the response speed of customer demand,improving the service quality and reducing the services of the operation cost.This paper based on various factors of enterprise distribution cost minimization and customer satisfaction maximization,To studay stochastic vehicle routing problems with uncertain travel time,a stochastic programming model was formulated.Result demonstrated that the proposed algorith obtained betterresults with higher convergence speed.%车辆路径问题是现代物流配送管理的一项重要内容，运输路径的合理选取，可以加快企业对客户需求的响应速度，提高服务质量，降低运营成本。本文在综合考虑企业运输成本最小化和客户满意度最大化的基础上，针对不确定配送时间的随机车辆路径问题，建立随机机会规划模型。最后通过实例对模型求解，结果表明该算法能取得更好的优化结果和更快的收敛速度。