Combining heuristics and Exact Algorithms: A Review

基于MAXBAND模型的交通灯同步启发式算法

A Heuristic Algorithm for Traffic Light Synchronization Based on the MAXBAND Model

解决交通网络上交通信号灯同步的一种广泛使用的方法是最大化汽车在街道一端启动并可以在不停车红灯的情况下到达另一端的时间（带宽最大化）。在文献中发现的混合整数线性模型，称为MAXBAND，可以通过优化求解器仅针对小的实例来求解。在本文中，我们详细审查了所有的限制，原来的线性模型，包括那些描述所有的循环路线图中，我们推广到目前为止，只提出了整数变量的一些界限，不考虑周期的问题。最后，我们提出了一个解决方案的算法，使用禁忌搜索和可变邻域搜索，我们进行了计算研究表明，它表现得非常好的大型实例。

An (R, S) Based Heuristic Model for the Stochastic Joint Replenishment Problem

This paper considers the periodic-review stochastic joint replenishment problem (JRP) under Bookbinder and Tan's static-dynamic uncertainty control policy. According to a static-dynamic uncertainty control rule, the decision maker fixes timing of replenishments once and for all at the beginning of the planning horizon, the inventory position is then raised to a predefined order-up-to-position at the beginning of each replenishment period. In this policy, freezing the replenishment times ameliorates the inherent difficulties pertinent to replenishment coordination of multiple products, whereas …

Exact and Heuristic Approaches to Drone Delivery Problems

The Flying Sidekick Traveling Salesman Problem (FSTSP) considers a delivery system composed by a truck and a drone. The drone launches from the truck with a single package to deliver to a customer. Each drone must return to the truck to recharge batteries, pick up another package, and launch again to a new customer location. This work proposes a novel Mixed Integer Programming (MIP) formulation and a heuristic approach to address the problem. The proposedMIP formulation yields better linear relaxation bounds than previously proposed formulations for all instances, and was capable of optimally …

Comparing Greedy Constructive Heuristic Subtour Elimination Methods for the Traveling Salesman Problem

This paper further defines the class of fragment constructive heuristics used to compute feasible solutions for the Traveling Salesman Problem into arc-greedy and node-greedy subclasses. Since these subclasses of heuristics can create subtours, two known methodologies for subtour elimination on symmetric instances are reviewed and are expanded to cover asymmetric problem instances. This paper introduces a third novel methodology, the Greedy Tracker, and compares it to both known methodologies. Computational results are generated across multiple symmetric and asymmetric instances. The results d…

Trends in the optimal location and sizing of electrical units in smart grids using meta-heuristic algorithms

The development of smart grids has effectively transformed the traditional grid system. This promises numerous advantages for economic values and autonomous control of energy sources. In smart grids development, there are various objectives such as voltage stability, minimized power loss, minimized economic cost and voltage profile improvement. Thus, researchers have investigated several approaches based on meta-heuristic optimization algorithms for the optimal location and sizing of electrical units in a distribution system. Meta-heuristic algorithms have been applied to solve different probl…

Heuristic Methods and Performance Bounds for Photonic Design

In the photonic design problem, a scientist or engineer chooses the physical parameters of a device to best match some desired device behavior. Many instances of the photonic design problem can be naturally stated as a mathematical optimization problem that is computationally difficult to solve globally. Because of this, several heuristic methods have been developed to approximately solve such problems. These methods often produce very good designs, and, in many practical applications, easily outperform 'traditional' designs that rely on human intuition. Yet, because these heuristic methods do…

具有广义上界约束的集合多重覆盖问题的松弛算法

Relaxation heuristics for the set multicover problem with generalized upper bound constraints

考虑了集合覆盖问题（SCP）的一个推广，引入了（i）多重覆盖和（ii）广义上界（GUB）约束.对于传统的SCP，定价方法已被引入到减少的实例的大小，和一些有效的启发式算法的基础上，这种减少技术已经开发出解决大规模的实例。然而，GUB约束通常使定价方法不那么有效，因为它们通常阻止解决方案包含高度评价的变量。为了克服这个问题，我们开发了启发式算法，以减少实例的大小，其中新的评估计划的变量引入考虑GUB约束。我们还开发了一个有效的实现2翻转邻域局部搜索算法，减少了候选人的数量在附近，而不牺牲解决方案的质量。为了引导搜索访问各种各样的好的解决方案，我们还介绍了一种路径重连方法，通过组合两个或两个以上的解决方案，目前为止获得的新的解决方案。根据基准实例的计算比较，所提出的方法成功地选择了少量的有前途的变量适当，即使是大规模的实例具有硬GUB约束，执行相当有效。

PaNGEA：GPU上的并行节点生成与探索算法

PaNGEA: Parallel Node Generation and Exploration Algorithm on GPU

本文提出PaNGEA，一种GPU友好的混合整数优化原始启发式算法，通过结合线性松弛与局部搜索并利用GPU批处理并行探索多个子问题，在283个实例上相比CPU减少8-18%间隙积分，多节点并行再减少12-19%。

车辆路径问题的启发式算法：序列还是集合optimization？

Heuristics for vehicle routing problems: Sequence or set optimization?

研究了基于车辆到客户“分配”和访问“排序”决策变量的容量约束车辆路径问题（CVRP）的结构分解。我们发现，启发式搜索集中在分配决策与系统的最佳选择的序列（使用协和TSP求解器）在每次移动评估是有希望的，但需要一个令人望而却步的计算工作。因此，我们引入了一个中间搜索空间，基于动态规划过程的Balas和Simonetti，它找到了一个很好的妥协之间的集约化和计算效率。各种加速技术提出了一个快速的探索：邻域减少，动态移动过滤器，内存结构和级联技术。最后，隧道策略的设计，重塑搜索空间的算法的进展。这些技术在经典局部搜索以及统一混合遗传搜索（UHGS）中的组合可以显着提高解的准确性。为只有256个客户的小实例找到了新的最佳解决方案。到目前为止，这些解决方案还没有在经典社区中实现。总的来说，这项研究允许更好地评估各自的影响，序列和分配优化，提出了新的方式相结合的优化这两个决策集，并打开了有前途的研究前景的CVRP及其变种。

强化学习在运筹学中的应用：技术综述与实践路线图

Reinforcement Learning and Operational Research: A Review of Methodological Integration and Research Directions

本文系统综述强化学习赋能运筹学的三种角色：动态序贯决策、组合优化集成及数字孪生扩展现实分析，并展望未来研究路线图。

Valid inequalities, preprocessing, and an effective heuristic for the uncapacitated three-level lot-sizing and replenishment problem with a distribution structure

We consider the uncapacitated three-level lot-sizing and replenishment problem with a distribution structure. In this NP-hard problem, a single production plant sends the produced items to replenish warehouses from where they are dispatched to the retailers in order to satisfy their demands over a finite planning horizon. The goal of the problem is to determine an integrated production and distribution plan minimizing the total costs, which comprehends fixed production and transportation setup as well as variable inventory holding costs. We describe new valid inequalities both in the space of …