A hybrid discrete particle swarm optimization for vehicle routing problem with simultaneous pickup and delivery

Vehicle routing problem (VRP) is an important and well-known combinatorial optimization problem encountered in many transport logistics and distribution systems. The VRP has several variants depending on tasks performed and on some restrictions, such as time windows, multiple vehicles, backhauls, simultaneous delivery and pick-up, etc. In this paper, we consider vehicle routing problem with simultaneous pickup and delivery (VRPSPD). The VRPSPD deals with optimally integrating goods distribution and collection when there are no precedence restrictions on the order in which the operations must be performed. Since the VRPSPD is an NP-hard problem, we present a heuristic solution approach based on particle swarm optimization (PSO) in which a local search is performed by variable neighborhood descent algorithm (VND). Moreover, it implements an annealing-like strategy to preserve the swarm diversity. The effectiveness of the proposed PSO is investigated by an experiment conducted on benchmark problem instances available in the literature. The computational results indicate that the proposed algorithm competes with the heuristic approaches in the literature and improves several best known solutions.     

Application of metaheuristics-based clustering algorithm to item assignment in a synchronized zone order picking system

Warehousing management policy is a crucial issue in logistic management. It must be managed effectively and efficiently to reduce the production cost as well as the customer satisfaction. Synchronized zoning system is a warehousing management policy which aims to increase the warehouse utilization and customer satisfaction by reducing the customer waiting time. This policy divides a warehouse into several zones where each zone has its own picker who can work simultaneously. Herein, item assignment plays an important role since it influences the order processing performance. This study proposes an application of metaheuristic algorithms, namely particle swarm optimization (PSO) and genetic algorithm (GA), for item assignment in synchronized zoning system. The original PSO and GA algorithms are modified so that it is suitable for solving item assignment problem. The datasets with different sizes are used for method validation. Results obtained by PSO and GA are then compared with the result of an existing algorithm. The experimental results showed that PSO and GA can perform better than the existing algorithm. These results also show that PSO has better performance than GA, especially for bigger problems. It proves that item assignment policy obtained by PSO and GA has higher utilization rates than the existing algorithm.     

A heuristic particle swarm optimization method for truss structures with discrete variables

A heuristic particle swarm optimizer (HPSO) algorithm for truss structures with discrete variables is presented based on the standard particle swarm optimizer (PSO) and the harmony search (HS) scheme. The HPSO is tested on several truss structures with discrete variables and is compared with the PSO and the particle swarm optimizer with passive congregation (PSOPC), respectively. The results show that the HPSO is able to accelerate the convergence rate effectively and has the fastest convergence rate among these three algorithms. The research shows the proposed HPSO can be effectively used to solve optimization problems for steel structures with discrete variables.     

Heuristic particle swarm optimization approach for test point selection with imperfect test

The problem of near-optimal test point set selection with imperfect test is solved by using the heuristic particle swarm optimization (HPSO) algorithm. First, to describe the uncertainty of each test, the testability analysis model and such indexes as fault detection rate, fault isolation rate, and false alarm rate are redefined. A heuristic function is then established to evaluate the detection isolation capability and uncertainty of the test point, which can provide heuristic information to improve the searching efficiency of particle swarm optimization (PSO). The heuristic function and least test cost principle are used as bases to design a fitness function of PSO algorithm for test point selection. Finally, the HPSO algorithm is proposed to select the optimal test point set for two practical systems. Simulation and experiment results show that the method can determine the global optimal test point accurately and effectively while meeting the requirements of testability indexes with least cost.     

基于双层模糊聚类的多车场车辆路径遗传算法

对大规模多车场车辆路径问题,设计了基于双层模糊聚类的改进遗传算法求解框架,上层静态区域划分利用k-means技术将多车场到多客户的问题转化为一对多的子问题,下层模糊聚类从保证客户满意度和整合物流资源的角度出发,利用模糊聚类算法根据客户需求属性形成基于客户订单配送的动态客户群。进一步,通过改进选择算子和交叉算子来设计车辆路径优化的遗传算法。通过随机算例仿真实验,证明了提出方法和求解策略的有效性。     

基于PSO信息传递模式的混合算法

粒子群优化算法（Particle Swarm Optimization，PSO）是一种基于群智能（Swarm Intelligence）的随机优化计算技术。PSO和遗传算法这两种算法相比较，PSO收敛快速准确，但编码形式单一，局限于解决实优化问题，而遗传算法编码形式灵活，解决问题广泛，但执行效率低于PS00。将粒子群算法的信息传递模式与遗传算法的编码和遗传操作相结合，提出一种混合算法。并推导了两个算法之间的密切联系。并通过组合优化和函数优化的基准测试集对算法进行测试，试验结果表明，该算法在收敛精度和速度优于传统遗传算法。同时，也观察到该算法取得了与粒子群算法一致的收敛现象。     

车辆路径问题的改进混合粒子群算法研究

针对各种启发式算法在求车辆路径问题(VRP)中的缺陷,提出了改进的混合粒子群算法(MHPSO)的求解方法.分析了基于速度-位置更新策略传统粒子群算法在解决离散的和组合优化问题的不足.考虑到算法在求解过程中种群多样性的损失过快,引进了种群的多样性测度参数-平均粒距,以保持种群的多样性.同时利用混沌运功的随机性、遍历性和规律性等特性,采用混沌初始化粒子编码.详细讨论了该算法在车辆路径问题中的求解策略.针对同一个实例,将改进的混合粒子群算法与遗传算法从多个角度进行比较.仿真结果表明,论文所提出的算法性能较好,可以快速、有效求得车辆路径问题的优化解或近似优化解.     

The r‐interdiction selective multi‐depot vehicle routing problem

The protection of critical facilities has been attracting increasing attention in the past two decades. Critical facilities involve physical assets such as bridges, railways, power plants, hospitals, and transportation hubs among others. In this study we introduce a bilevel optimization problem for the determination of the most critical depots in a vehicle routing context. The problem is modeled as an attacker–defender game (Stackelberg game) from the perspective of an adversary agent (the attacker) who aims to inflict maximum disruption on a routing network. We refer to this problem as the r‐interdiction selective multi‐depot vehicle routing problem (RI‐SMDVRP). The attacker is the decision maker in the upper level problem (ULP) who chooses r depots to interdict with certainty. The defender is the decision maker in the lower level problem (LLP) who optimizes the vehicle routes in the wake of the attack. The defender has to satisfy all customer demand either using the remaining depots or through outsourcing to a third party logistics service provider. The ULP is solved through exhaustive enumeration, which is viable when the cardinality of interdictions does not exceed five among nine depots. For the LLP we implement a tabu search heuristic adapted to the selective multi‐depot VRP. Our results are obtained on a set of RI‐SMDVRP instances synthetically constructed from standard MDVRP test instances.     

基于混沌粒子群算法的物流配送路径优化

通过结合混沌的遍历性和粒子群的快速性的优点,提出了一种用于求解物流配送路径优化问题的混沌粒子群优化算法。该算法利用混沌变量产生初始粒子群,对子代部分粒子群进行微小扰动,随着搜索过程深入逐步调整扰动幅度,通过调整惯性权重因子克服标准PSO算法的早熟和易陷入局部最优值等缺陷。将混沌粒子群优化算法用于物流配送路径优化,建立了数学模型,在此基础上设计了相应的算法。将该算法和遗传算法、标准粒子群算法进行比较,证明了其收敛速度和寻优能力的优越性。     

基于启发式带时间窗的车辆路径规划问题求解

车辆路径规划问题广泛地存在于现代物流行业中, 该问题属于NP难的组合优化问题. 随着客户需求的多样化、道路限行等因素的影响, 该问题变得更加的复杂, 采用传统的组合优化方法和运筹学方法往往难以求解. 本文对一类常见的带时间窗的车辆路径规划问题进行了研究, 根据时间窗参数来调整客户的优先级, 以减少车辆的等待时间, 由此改进了几个常见的启发式算法, 并对56个常见的车辆路径规划问题进行了测试, 实验结果表明, 改进的节约算法在带容量约束的车辆路径问题中效果较好, 改进的插入法则在带时间窗的车辆路径问题中具有优越性, 另外, 改进的启发式算法在4个测试用例上使用更多车辆时可使总路程优于已知最优值.     

多物流中心共同配送的车辆路径问题研究

研究多物流中心共同配送的车辆路径问题。首先考虑客户服务关系变化与客户需求的异质性情况,设计一种共享客户需求、配送车辆与物流中心的共享物流模式;再综合考虑车辆容量、油耗、碳排放、最长行驶时间、客户需求量与服务时间等因素,以总成本最小为目标构建多物流中心共同配送的车辆路径规划模型,并设计一种改进蚁群算法进行求解;最后采用多类型算例进行仿真实验,结果表明共享物流模式能有效避免交叉配送与迂回运输等不合理现象,降低物流成本,缩短车辆行驶距离,减少车辆碳排放,促进物流与环境的和谐发展。     

QoS multicast routing using a quantum-behaved particle swarm optimization algorithm

QoS multicast routing in networks is a very important research issue in networks and distributed systems. It is also a challenging and hard problem for high-performance networks of the next generation. Due to its NP-completeness, many heuristic methods have been employed to solve the problem. This paper proposes the modified quantum-behaved particle swarm optimization (QPSO) method for QoS multicast routing. In the proposed method, QoS multicast routing is converted into an integer programming problem with QoS constraints and is solved by the QPSO algorithm combined with loop deletion operation. The QPSO-based routing method, along with the routing algorithms based on particle swarm optimization (PSO) and genetic algorithm (GA), is tested on randomly generated network topologies for the purpose of performance evaluation. The simulation results show the efficiency of the proposed method on QoS the routing problem and its superiority to the methods based on PSO and GA.     

听觉信号盲分离的混合粒子群优化算法

为了解决基本粒子群盲分离算法收敛速度慢、优化精度低的问题,提出用基于群体自适应变异和个体退火操作的混合粒子群优化算法（HPSO）来实现听觉信号盲分离。与模拟退火算法（SA）和基本粒子群算法（PSO）相比,该算法保持了基本粒子群算法简单、容易实现的特点,又能进行自适应变异,改善了其摆脱局部极值点的能力。仿真对比结果表明,基于该改进算法的盲分离效果良好,具有收敛速度快、性能稳定等特点。     

定位-运输路线安排问题的改进离散粒子群优化算法

定位-运输路线安排问题(LRP)是集成物流中的一个NP-hard难题,为求解一类特殊的LRP问题,提出改进的离散粒子群优化算法.该方法采用整体优化的思想,将LAP和VRP集成在一起.通过合适的粒子编码方式,并改进粒子的运动方程,引入相应的变异算子和趋同扰动算子等,使得算法的适用性和性能获得了改善.通过仿真实验及与另2个典型算法的比较分析,证明了该算法的有效性.     

A two-stage heuristic method for vehicle routing problem with split deliveries and pickups

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.     

Solving the multi-stage portfolio optimization problem with a novel particle swarm optimization

Solving the multi-stage portfolio optimization (MSPO) problem is very challenging due to nonlinearity of the problem and its high consumption of computational time. Many heuristic methods have been employed to tackle the problem. In this paper, we propose a novel variant of particle swarm optimization (PSO), called drift particle swarm optimization (DPSO), and apply it to the MSPO problem solving. The classical return-variance function is employed as the objective function, and experiments on the problems with different numbers of stages are conducted by using sample data from various stocks in S&P 100 index. We compare performance and effectiveness of DPSO, particle swarm optimization (PSO), genetic algorithm (GA) and two classical optimization solvers (LOQO and CPLEX), in terms of efficient frontiers, fitness values, convergence rates and computational time consumption. The experiment results show that DPSO is more efficient and effective in MSPO problem solving than other tested optimization tools.     

一种辨识Wiener-Hammerstein模型的新方法

针对非线性Wiener-Hammerstein模型,提出利用粒子群优化算法对非线性模型进行辨识的新方法.该方法的基本思想是将非线性系统的辨识问题转化为参数空间上的优化问题;然后采用粒子群优化算法获得该优化问题的解.为了进一步增强粒子群优化算法的辨识性能,提出利用一种混合粒子群优化算法.最后,仿真结果验证了该方法的有效性和可行性.     

广义粒子群优化模型

粒子群优化算法提出至今一直未能有效解决的离散及组合优化问题．针对这个问题,文中首先回顾了粒子群优化算法在整数规划问题的应用以及该算法的二进制离散优化模型,并分析了其缺陷．然后,基于传统算法的速度一位移更新操作,在分析粒子群优化机理的基础上提出了广义粒子群优化模型（GPSO）,使其适用于解决离散及组合优化问题．GPSO模型本质仍然符合粒子群优化机理,但是其粒子更新策略既可根据优化问题的特点设计,也可实现与已有方法的融合．该文以旅行商问题（TSP）为例,针对遗传算法（GA）解决该问题的成功经验,使用遗传操作作为GPSO模型中的更新算子,进一步提出基于遗传操作的粒子群优化模型,并以Inverover算子作为模型中具体的遗传操作设计了基于GPSO模型的TSP算法．与采用相同遗传操作的GA比较,基于GPSO模型的算法解的质量与收敛稳定性提高,同时计算费用显著降低．     

Parameter extraction for PSP MOSFET model using hierarchical particle swarm optimization

The particle swarm optimization (PSO) algorithm is applied to the problem of MOSFET parameter extraction for the first time. It is shown to perform significantly better than the genetic algorithm (GA). Several modifications of the basic PSO algorithm have been implemented: (a) Hierarchical PSO (HPSO) in which particles are hierarchically arranged and influenced by the positions of the local and global leaders, (b) memory loss operation due to which a particle forgets its past best position, (c) intensive local search in which the solution space around the global leader is searched with a high resolution, and (d) adaptive inertia which causes the inertia of the particles to change adaptively, depending on the fitness of the population. It is demonstrated that the above features improve the performance of the basic PSO algorithm both for the MOSFET parameter extraction problem and for benchmark functions.     

求解整合资源条件下的运输调度问题

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,CPSO)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。