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Demand-responsive transport (DRT) could be an alternative for extending the accessibility of high-speed rail (HSR) servicing cities in rural environments, where fixed public transport does not provide efficient services. This paper proposes a method to analyse the factors that influence the implementation of DRT systems for inter-urban mobility, connecting and integrating towns in rural areas. Methodologically, a vehicle routing problem analysis in a GIS-based environment is applied to a theoretical case study to evaluate the factors that influence DRT efficiency in different scenarios, considering the specific singularities of this kind of inter-urban long-distance mobility. The results suggest the optimal DRT solutions in these rural contexts to be those that, after adjusting the fleet to specific demands, use low-capacity vehicles, which are much better adapted to the geography of sparsely populated areas. Moreover, in adapting DRT systems to HSR travellers' needs, windows catering to these needs should incorporate the option of setting the pickup or arrival times. This paper demonstrates that DRT systems could reach significant levels of service in rural areas compared with fixed lines and even private vehicles, especially when evaluating key aspects of the system's efficiency for its implementation. [ABSTRACT FROM AUTHOR]

The School Bus Routing Problem (SBRP) is a challenging optimization problem that has received increasing attention in recent years. The problem is composed of three sub-problems: facility location selection, assignment problem, and vehicle routing problem, which can be solved in a single stage or across multiple stages. In this study, we propose a novel two-stage approach to solve the SBRP that combines Fuzzy C Means (FCM) and K-means clustering algorithms with a Genetic Algorithm (GA). In the first stage, we used FCM and K-means to identify the optimal bus stop locations and assigned students to the nearest stop based on the distance metric. This two-stage approach reduces the search space and improves the efficiency of the GA in the second stage. In the second stage, we employed the GA to generate the optimal vehicle route that minimizes the total distance traveled by all vehicles. We compared our results with those in the literature and found that the K Means-GA approach outperformed the previous results. However, the FCM-GA approach yielded significantly inferior results, indicating that the choice of clustering algorithm plays a crucial role in the performance of the overall system. Our study provides insights into the importance of selecting appropriate clustering algorithms for solving the SBRP and proposes a two-stage solution that can be easily implemented in real-world scenarios. Our approach reduces the computational time and provides an effective solution for reducing the total distance traveled by school buses. [ABSTRACT FROM AUTHOR]

The vehicle routing problem with time windows (VRPTW) is a widely studied combinatorial optimization problem in supply chains and logistics within the last decade. Recent research has explored the potential of deep reinforcement learning (DRL) as a promising solution for the VRPTW. However, the challenge of addressing the VRPTW with many conflicting objectives (MOVRPTW) still remains for DRL. The MOVRPTW considers five conflicting objectives simultaneously: minimizing the number of vehicles required, the total travel distance, the travel time of the longest route, the total waiting time for early arrivals, and the total delay time for late arrivals. To tackle the MOVRPTW, this study introduces the MTMO/DRP-AT, a multi-task multi-objective evolutionary search algorithm, by making full use of both DRL and the multitasking mechanism. In the MTMO/DRL-AT, a two-objective MOVRPTW is constructed as an assisted task, with the objectives being to minimize the total travel distance and the travel time of the longest route. Both the main task and the assisted task are simultaneously solved in a multitasking scenario. Each task is decomposed into scalar optimization subproblems, which are then solved by an attention model trained using DRL. The outputs of these trained models serve as the initial solutions for the MTMO/DRL-AT. Subsequently, the proposed algorithm incorporates knowledge transfer and multiple local search operators to further enhance the quality of these promising solutions. The simulation results on real-world benchmarks highlight the superior performance of the MTMO/DRL-AT compared to several other algorithms in solving the MOVRPTW. [ABSTRACT FROM AUTHOR]

Low-carbon logistics is an emerging and sustainable development industry in the era of a low-carbon economy. The end-to-end deep reinforcement learning (DRL) method with an encoder-decoder framework has been proven effective for solving logistics problems. However, in most cases, the recurrent neural networks (RNN) and attention mechanisms are used in encoders and decoders, which may result in the long-distance dependence problem and the neglect of the correlation between query vectors. To surround this problem, we propose an improved transformer model (TAOA) with both multi-head attention mechanism (MHA) and attention to attention mechanism (AOA), and apply it to solve the low-carbon multi-depot vehicle routing problem (MDVRP). In this model, the MHA and AOA are implemented to solve the probability of route nodes in the encoder and decoder. The MHA is used to process different parts of the input sequence, which can be calculated in parallel, and the AOA is used to deal with the deficiency problem of correlation between query results and query vectors in the MHA. The actor-critic framework based on strategy gradient is constructed to train model parameters. The 2opt operator is further used to optimize the resulting routes. Finally, extensive numerical studies are carried out to verify the effectiveness and operation efficiency of the proposed TAOA, and the results show that the proposed TAOA performs better in solving the MDVRP than the traditional transformer model (Kools), genetic algorithm (GA), and Google OR-Tools (Ortools). [ABSTRACT FROM AUTHOR]

In order to improve the delivery efficiency of logistics, this paper proposed a vehicle routing problem with drone and time window considered by the time window, UAV (unmanned aerial vehicle) power change and multi-point continuous delivery of UAV. Then, this paper proposed a hybrid particle swarm optimization algorithm with local search to solve it. Based on the hybrid particle swarm optimization algorithm, the proposed algorithm transformed the problem solution space into the algorithm search space by constructing an efficient encoding and decoding strategy. Further, the proposed algorithm combined a single point insertion strategy, a vehicle replacement strategy and a UAV replacement strategy to form a local search strategy to improve the optimization ability. The experimental results show that the proposed model is more efficient than the model of pure vehicle distribution and saves 31.51% of the cost. The proposed algorithm is better than the four comparison algorithms, and its highest optimization rate is 82.08%. [ABSTRACT FROM AUTHOR]

Reducing material waste and computation time are primary objectives in cutting and packing problems (C &P). A solution to the C &P problem consists of many steps, including the grouping of items to be nested and the arrangement of the grouped items on a large object. Current algorithms use meta-heuristics to solve the arrangement problem directly without explicitly addressing the grouping problem. In this paper, we propose a new pipeline for the nesting problem that starts with grouping the items to be nested and then arranging them on large objects. To this end, we introduce and motivate a new concept, namely the Geometrical Compatibility Index (GCI). Items with higher GCI should be clustered together. Since no labels exist for GCIs, we propose to model GCIs as bidirectional weighted edges of a graph that we call geometrical relationship graph (GRG). We propose a novel reinforcement-learning-based framework, which consists of two graph neural networks trained in an actor-critic-like fashion to learn GCIs. Then, to group the items into clusters, we model the GRG as a capacitated vehicle routing problem graph and solve it using meta-heuristics. Experiments conducted on a private dataset with regularly and irregularly shaped items show that the proposed algorithm can achieve a significant reduction in computation time (30% to 48%) compared to an open-source nesting software while attaining similar trim loss on regular items and a threefold improvement in trim loss on irregular items. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to formulate a new class of vehicle routing problem with an objective to minimise the total cost of raw material collection and derive a new approach to solve optimization problems. This study can help to select the optimum number of suppliers based on cost. Design/methodology/approach: To model the raw material vehicle routing problem, a mixed integer linear programming (MILP) problem is formulated. An interesting phenomenon added to the proposed problem is that there is no compulsion to visit all suppliers. To guarantee the demand of semiconductor industry, all visited suppliers should reach a given raw material capacity requirement. To solve the proposed model, the authors developed a novel hybrid approach that is a combination of block and edge recombination approaches. To avoid bias, the authors compare the results of the proposed methodology with other known approaches, such as genetic algorithms (GAs) and ant colony optimisation (ACO). Findings: The findings indicate that the proposed model can be useful in industries, where multiple suppliers are used. The proposed hybrid approach provides a better sequence of suppliers compared to other heuristic techniques. Research limitations/implications: The data used in the proposed model is generated based on previous literature. The problem derives from the assumption that semiconductor industries use a variety of raw materials. Practical implications: This study provides a new model and approach that can help practitioners and policymakers select suppliers based on their logistics costs. Originality/value: This study provides two important contributions in the context of the supply chain. First, it provides a new variant of the vehicle routing problem in consideration of raw material collection; and second, it provides a new approach to solving optimisation problems. [ABSTRACT FROM AUTHOR]

In this study, we present a framework for optimizing pick-up and delivery operations in bike-sharing systems (BSSs), with particular emphasis on inventory rebalancing and vehicle routing to enhance operational efficiency. By employing a hybrid genetic algorithm (HGA), this study integrates sophisticated predictive models with multi-objective optimization techniques to strike a balance between operational efficiency and demand fulfillment in urban bike-share networks. For probabilistic demand forecasting, the DeepAR model is applied to a large number of bike stations clustered by geological proximity to enable stochastic inventory management. Our proposed HGA approach leverages both the genetic algorithm for generating feasible vehicle routes and mixed-integer programming for bike rebalancing to minimize travel distances while maintaining balanced inventory levels across all clustered stations. Through rigorous empirical evaluations, we demonstrate the effectiveness of our proposed methodology in improving service quality, thus making significant contributions to sustainable urban mobility. This study not only pushes the boundaries of theoretical knowledge in BSS logistics optimization but also offers managerial insights for practical implementation, particularly in densely populated urban settings. [ABSTRACT FROM AUTHOR]

Intelligent scheduling plays a crucial role in minimizing transportation expenses and enhancing overall efficiency. However, most of the existing scheduling models fail to comprehensively account for the requirements of urban development, as exemplified by the vehicle routing problem with time windows (VRPTW), which merely specifies the minimization of path length. This paper introduces a new model of the heterogeneous green city vehicle routing problem with time windows (HGCVRPTW), addressing challenges in urban logistics. The HGCVRPTW model considers carriers with diverse attributes, recipients with varying tolerance for delays, and fluctuating road congestion levels impacting carbon emissions. To better deal with the HGCVRPTW, an adaptive multi-objective genetic algorithm based on the greedy initialization strategy (AMoGA-GIS) is proposed, which includes the following three advantages. Firstly, considering the impact of initial information on the search process, a greedy initialization strategy (GIS) is proposed to guide the overall evolution during the initialization phase. Secondly, the adaptive multiple mutation operators (AMMO) are introduced to improve the diversity of the population at different evolutionary stages according to their success rate of mutation. Moreover, we built a more tailored testing dataset that better aligns with the challenges faced by the HGCVRPTW. Our extensive experiments affirm the competitive performance of the AMoGA-GIS by comparing it with other state-of-the-art algorithms and prove that the GIS and AMMO play a pivotal role in advancing algorithmic capabilities tailored to the HGCVRPTW. [ABSTRACT FROM AUTHOR]

In current research on task offloading and resource scheduling in vehicular networks, vehicles are commonly assumed to maintain constant speed or relatively stationary states, and the impact of speed variations on task offloading is often overlooked. It is frequently assumed that vehicles can be accurately modeled during actual motion processes. However, in vehicular dynamic environments, both the tasks generated by the vehicles and the vehicles' surroundings are constantly changing, making it difficult to achieve real-time modeling for actual dynamic vehicular network scenarios. Taking into account the actual dynamic vehicular scenarios, this paper considers the real-time non-uniform movement of vehicles and proposes a vehicular task dynamic offloading and scheduling algorithm for single-task multi-vehicle vehicular network scenarios, attempting to solve the dynamic decision-making problem in task offloading process. The optimization objective is to minimize the average task completion time, which is formulated as a multi-constrained non-linear programming problem. Due to the mobility of vehicles, a constraint model is applied in the decision-making process to dynamically determine whether the communication range is sufficient for task offloading and transmission. Finally, the proposed vehicular task dynamic offloading and scheduling algorithm based on muti-agent deep deterministic policy gradient (MADDPG) is applied to solve the optimal solution of the optimization problem. Simulation results show that the algorithm proposed in this paper is able to achieve lower latency task computation offloading. Meanwhile, the average task completion time of the proposed algorithm in this paper can be improved by 7.6% compared to the performance of the MADDPG scheme and 51.1% compared to the performance of deep deterministic policy gradient (DDPG). [ABSTRACT FROM AUTHOR]

The Single Source Capacitated Facility Location Problem (SSCFLP) consists of determining locations for facilities to meet customer demands so that each customer must be served by a single facility. This paper proposes a matheuristic algorithm for solving large-scale SSCFLP instances that combines neighborhood-based heuristic procedures with the solution of two binary linear programming sub-problems through a general-purpose solver. The proposed algorithm starts from the optimal solution of the linear relaxation of the SSCFLP to reduce its size and identify promising potential locations for opening facilities. Computational experiments were performed on two benchmark sets of large instances. For one of them, the developed algorithm obtained optimal solutions for all instances. For the other set, it provided average relative deviations slightly lower than those of three relevant algorithms from the literature. These results allow us to conclude that the proposed algorithm generates good-quality solutions and is competitive in solving large-scale SSCFLP instances. [ABSTRACT FROM AUTHOR]

The activities of the traffic department mainly contribute to the generation of greenhouse gas (GHG) emissions. The swift expansion of the traffic department results in a significant increase in global pollution levels, adversely affecting human health. To address GHG emissions and propose impactful solutions for reducing fuel consumption in vehicles, environmental considerations are integrated with the core principles of the vehicle routing problem. This integration gives rise to the pollution-routing problem (PRP), which aims to optimize routing decisions with a focus on minimizing environmental impact. At the same time, the retail distribution system explores the use of an omni-channel approach as a transportation mode adopted in this study. The objectives of this research include minimizing total travel costs and fuel consumption while aiming to reduce GHG emissions, promoting environmental sustainability, and enhancing the convenience of shopping and pickup for customers through the integration of online and offline modes. This problem is NP-hard; therefore, the Non-dominated Sorting Simplified Swarm Optimization (NSSO) algorithm is employed. NSSO combines the non-dominated technique of Non-dominated Sorting Genetic Algorithm II (NSGA-II) with the update mechanism of Simplified Swarm Optimization to obtain a set of Pareto-optimal solutions. Moreover, the NSSO, a multi-objective evolutionary algorithm, is adopted to address multi-objective problems. The PRP benchmark dataset is utilized, and the results are compared with two other multi-objective evolutionary algorithms: NSGA-II and Non-dominated Sorting Particle Swarm Optimization (NSPSO). The findings of the study confirm that NSSO exhibits feasibility, provides good solutions, and achieves faster convergence compared with the other two algorithms, NSGA-II and NSPSO. [ABSTRACT FROM AUTHOR]

To effectively solve the reverse logistics distribution problem caused by the increasing number of scrapped parts in the automotive market, this study constructs a multi-trip green vehicle routing problem model with time windows by comprehensively considering the coordination between carbon dioxide emissions and cost efficiency. A hybrid adaptive genetic algorithm is proposed to solve this problem, featuring innovative improvements in the nearest neighbor rule based on minimum cost, adaptive strategies, bin packing algorithm based on the transfer-of-state equation, and large-scale neighborhood search. Additionally, to efficiently obtain location data for supplier factory sites in the distribution network, a coordinate extraction method based on image recognition technology is proposed. Finally, the scientific validity of this study is verified based on the actual case data, and the robust optimization ability of the algorithm is verified by numerical calculations of different examples. This research not only enriches the study of green vehicle routing problems but also provides valuable insights for the industry to achieve cost reduction, efficiency enhancement, and sustainable development in reverse logistics. [ABSTRACT FROM AUTHOR]

Studying the order delivery strategy considering urban traffic restrictions to reduce the average delivery time of orders, improve the consistency of delivery time and customer satisfaction is of great significance. A steering-restricted distribution network was constructed by setting up steerable nodes. And with the goal of minimizing the average delivery time, a multi-vehicle real-time pickup and delivery path optimization model was established considering the dynamics of the orders based on the turn restriction network. And two delayed distribution strategies, IGNORE and wait & return (W&R), were designed to solve the problem. In the study analysis, the number and distance of steerable nodes were adjusted to simulate two kinds of road networks: dense and sparse. Through numerical simulation and genetic algorithm solution, the stability of the model and the applicability of the strategy were verified, the average delivery time of IGNORE and W&R strategies under these two networks, different order quantities, the number of delivery personnel and lengths of rolling time domains were obtained, and the reasons for the fluctuation of the average delivery time were analyzed. The results show that the IGNORE strategy is applicable to the case of small network with few orders, and the average delivery time of orders decreases as the rolling time domain time shortens. The W&R strategy is suitable for larger distribution networks, and the more the number of steerable nodes in the network, the average delivery time of orders decreases. The research conclusion has certain reference significance for the real-time delivery platform to optimize the delivery strategy and improve customer satisfaction. [ABSTRACT FROM AUTHOR]

In this article, a single-server Markovian queueing model with balking is closely considered. Balking refers to a particular behavior of an impatient customer. Upon arrival, if the queue is too long, a customer may join the queue or leave the system without getting served. If he decides not to join the queue and leaves the system without getting served, this phenomenon is called as balking. In this article, balking probability is treated as a function rather than a constant, which depends on the number of customers present in the system. The emphasis of this article will mainly be placed on maximum likelihood and Bayesian estimation of traffic intensity ( ρ), average size of system ( L s ), and average size of queue ( L q ). In addition, a simulation study has also been performed to support our findings. [ABSTRACT FROM AUTHOR]

In the context of the carbon trading mechanism, this study investigated a multi-visit vehicle routing problem with a truck-drone collaborative delivery model. This issue involves the route of a truck fleet and drones, each truck equipped with a drone, allowing drones to provide services to multiple customers. Considering the carbon emissions during both the truck's travel and the drone's flight, this study established a mixed integer programming model to minimize the sum of fixed costs, transportation costs, and carbon trading costs. A two-stage heuristic algorithm was proposed to solve the problem. The first stage employed a "Scanning and Heuristic Insertion" algorithm to generate an initial feasible solution. In the second stage, an enhanced variable neighborhood search algorithm was designed with problem-specific neighborhood structures and customized search strategies. The effectiveness of the proposed algorithm was validated with numerical experiments. Additionally, this study analyzed the impact of various factors on carbon trading costs, revealing that there exists an optimal combination of drones and trucks. It was also observed that changes in carbon quotas do not affect carbon emissions but do alter the total delivery costs. These results provide insights for logistics enterprise operations management and government policy-making. [ABSTRACT FROM AUTHOR]

In order to improve the transportation efficiency of cold chain logistics and achieve the low-carbon goal of energy saving and emission reduction, this paper discusses the multi-objective low- carbon cold chain vehicle routing problem in cold-chain logistics distribution (MOLCVRPCLD). Compared with the existing literature, this paper considers a more low-carbon mixed fleet of electric vehicles and fuel vehicles, and establishes an optimization model with the goal of optimal comprehensive cost and minimum carbon emissions. Comprehensive cost includes fixed cost of vehicles, time window cost, cargo damage cost, fuel consumption cost and power consumption cost. Carbon emissions includes fuel emissions and refrigeration emissions. According to the characteristics of the model, a non-dominated sorting genetic algorithm II (NSGA-II) is designed to solve the model. And genetic algorithm (GA) is used to optimize the two targets respectively to verify the effectiveness of the model and algorithm. [ABSTRACT FROM AUTHOR]

This research delves into the dynamic landscape of transportation systems, with a specific focus on the integration of drones and conventional vehicles. The study presents a Mixed Integer Programming (MIP) model for the Capacitated Multi-Drone Assisted Vehicle Routing Problem (mDroneCVRP), aiming to minimize the time of the last vehicle's arrival at the warehouse. It is essential to highlight that the proposed model was effectively solved using the CPLEX algorithm within the GAMS framework, underscoring the sophistication of the solution approach. The integration of multiple drones into the routing process proves to be instrumental in significantly reducing service time, demonstrating the efficacy of synergizing drone and truck operations. As the number of nodes escalates, emphasizing the necessity for heuristic approaches to address larger instances, the study provides valuable insights into the judicious use of drones in synchronized routing operations. Furthermore, the research challenges conventional assumptions by permitting drones to take off from and land on different vehicles, thereby augmenting operational capabilities and adeptly tackling contemporary transportation challenges. [ABSTRACT FROM AUTHOR]

A recent study on the classical capacitated vehicle routing problem (CVRP) introduced an adaptive version of the widely used iterated local search paradigm, hybridized with a path-relinking (PR) strategy. The solution method, called adaptive iterated local search (AILS)-PR, outperformed existing meta-heuristics for the CVRP on benchmark instances. However, tests on large-scale instances suggest that PR is too slow, making AILS-PR less advantageous in this case. To overcome this challenge, this paper presents an AILS combined with mechanisms to handle large CVRP instances, called AILS-II. The computational cost of this implementation is reduced, whereas the algorithm also searches the solution space more efficiently. AILS-II is very competitive on smaller instances, outperforming the other methods from the literature with respect to the average gap to the best-known solutions. Moreover, AILS-II consistently outperforms the state of the art on larger instances with up to 30,000 vertices. History: Accepted by Ted Ralphs, Area Editor for Software Tools. This paper has been accepted for the INFORMS Journal on Computing Special Issue on Software Tools for Vehicle Routing. Funding: This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo [Grants 2013/07375-0, 2019/22067-6, and 2022/05803-3] and the Conselho Nacional de Desenvolvimento Científico e Tecnológico [Grants 309385/2021-0 and 403735/2021-1]. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information (https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2023.0106) as well as from the IJOC GitHub software repository (https://github.com/INFORMSJoC/2023.0106). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/. [ABSTRACT FROM AUTHOR]

We introduce RoutingBlocks, a versatile open-source Python package designed to simplify the development of algorithms for vehicle routing problems with intermediate stops (VRPIS). The package offers a variety of modular algorithmic components and optimized data structures crafted specifically to address key challenges of VRPIS, such as a lack of exact constant-time move evaluations and difficult station visit decisions. By using a unified solution and instance representation that abstracts problem-specific behavior (for example, constraint checking, move evaluation, and cost computation) into well-defined interfaces, RoutingBlocks maintains a clear separation between algorithmic components and specific problem configurations, thus allowing the application of the same algorithm to a variety of problem settings. Leveraging an efficient C++ implementation for performance-critical core elements, RoutingBlocks combines the high performance of C++ with the user-friendliness and adaptability of Python, thereby streamlining the development of effective metaheuristic algorithms. As a result, researchers using RoutingBlocks can focus on their algorithms' core features, allocating more resources to innovation and advancement in the VRPIS domain. History: Accepted by Ted Ralphs, Area Editor for Software Tools. This paper has been accepted for the INFORMS Journal on Computing Special Issue on Software Tools for Vehicle Routing. [ABSTRACT FROM AUTHOR]

The optimization community has made significant progress in solving vehicle routing problems (VRPs) to optimality using sophisticated branch-cut-and-price (BCP) algorithms. VRPSolver is a BCP algorithm with excellent performance in many VRP variants. However, its complex underlying mathematical model makes it hardly accessible to routing practitioners. To address this, VRPSolverEasy provides a Python interface to VRPSolver that does not require any knowledge of mixed integer programming modeling. Instead, routing problems are defined in terms of familiar elements, such as depots, customers, links, and vehicle types. VRPSolverEasy can handle several popular VRP variants and arbitrary combinations of them. History: Accepted by Ted Ralphs, Area Editor for Software Tools. This paper has been accepted for the INFORMS Journal on Computing Special Issue on Software Tools for Vehicle Routing. Funding: This work was supported by Faperj [Grant E-26/202.887/2017] and Conselho Nacional de Desenvolvimento Científico e Tecnológico [Grant 305684/2022-1]. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information (https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2023.0103) as well as from the IJOC GitHub software repository (https://github.com/INFORMSJoC/2023.0103). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/. [ABSTRACT FROM AUTHOR]

We introduce PyVRP, a Python package that implements hybrid genetic search in a state-of-the-art vehicle routing problem (VRP) solver. The package is designed for the VRP with time windows (VRPTW) but can be easily extended to support other VRP variants. PyVRP combines the flexibility of Python with the performance of C++ by implementing (only) performance-critical parts of the algorithm in C++ while being fully customizable at the Python level. PyVRP is a polished implementation of the algorithm that ranked first in the 2021 DIMACS VRPTW challenge and, after improvements, ranked first on the static variant of the EURO meets NeurIPS 2022 vehicle routing competition. The code follows good software engineering practices and is well documented and unit tested. PyVRP is freely available under the liberal MIT license. Through numerical experiments, we show that PyVRP achieves state-of-the-art results on the VRPTW and capacitated VRP. We hope that PyVRP enables researchers and practitioners to easily and quickly build on a state-of-the-art VRP solver. History: Accepted by Ted Ralphs, Area Editor for Software Tools. This paper has been accepted for the INFORMS Journal on Computing Special Issue on Software Tools for Vehicle Routing. Funding: Funding was provided by TKI Dinalog, Topsector Logistics, and the Dutch Ministry of Economic Affairs and Climate Policy. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information (https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2023.0055) as well as from the IJOC GitHub software repository (https://github.com/INFORMSJoC/2023.0055). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/. There is a video associated with this paper. Click here to view the Video Overview. To save the file, right click and choose "Save Link As" from the menu. [ABSTRACT FROM AUTHOR]

The cutting plane method is a key technique for successful branch-and-cut and branch-price-and-cut algorithms that find the exact optimal solutions for various vehicle routing problems (VRPs). Among various cuts, the rounded capacity inequalities (RCIs) are the most fundamental. To generate RCIs, we need to solve the separation problem, whose exact solution takes a long time to obtain; therefore, heuristic methods are widely used. We design a learning-based separation heuristic algorithm with graph coarsening that learns the solutions of the exact separation problem with a graph neural network (GNN), which is trained with small instances of 50 to 100 customers. We embed our separation algorithm within the cutting plane method to find a lower bound for the capacitated VRP (CVRP) with up to 1,000 customers. We compare the performance of our approach with CVRPSEP, a popular separation software package for various cuts used in solving VRPs. Our computational results show that our approach finds better lower bounds than CVRPSEP for large-scale problems with 400 or more customers, whereas CVRPSEP shows strong competency for problems with less than 400 customers. History: Accepted by Andrea Lodi, Area Editor for Design & Analysis of Algorithms–Discrete. Funding: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) [RS-2023-00259550] and the Institute of Information & Communications Technology Planning & Evaluation (IITP) grant funded by the Korean government (MSIT) [2022-0-01032, Development of Collective Collaboration Intelligence Framework for Internet of Autonomous Things]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/ijoc.2022.0310. [ABSTRACT FROM AUTHOR]

In urban environments, the bicycle-sharing system (BSS) has emerged as a vital complement to public transportation, effectively bridging gaps in urban mobility. The successful operation of these systems is contingent upon ensuring the timely availability of bicycles and docking spaces, a challenge particularly pronounced during peak hours. Addressing this, our study introduces a novel approach for optimizing the rebalancing of BSS. We have developed a time-windowed rebalancing request generator, which, in conjunction with a route planning algorithm based on variable neighborhood search (VNS), provides a robust solution to this issue. This iterative evolutionary algorithm not only refines solutions progressively but also incorporates a shaking process to enhance the possibility of achieving global optimization. Our methodology further includes an algorithm for generating initial solutions, alongside two shaking processes designed to improve efficiency. We validate our approach using real-world data from Taipei's Youbike system, demonstrating superior performance in rebalancing efficiency compared to existing algorithms. Our study contributes to the optimization of BSS rebalancing, offering practical insights for urban transportation planning. [ABSTRACT FROM AUTHOR]

This research addresses the Inventory-Routing Problem (IRP) with priority customers under conditions of uncertainty. The problem involves devising a plan to supply a set of customers from a facility, establishing precedence rules, and making transportation and inventory management decisions while considering uncertainty in customer demand. Priority in deliveries is assigned to customers in the health sector in accordance with government regulations. Companies must uphold product quality for health sector customers while simultaneously aiming to minimize total costs. We propose a fuzzy mixed-integer linear programming model to solve the IRP with priority customers and uncertainty in demand rates, modeled using triangular fuzzy numbers. To convert the fuzzy linear programming model into a deterministic one, an ordering method for fuzzy numbers is applied. The model is implemented using CPLEX, and a set of benchmark instances is solved. The primary results indicate that prioritizing customers leads to an increase in total costs due to visiting these customers first on each route created. Additionally, routes without priority customers exhibit higher average vehicle capacity utilization. In most cases, the solutions obtained maintain quality within the specified time limits. [ABSTRACT FROM AUTHOR]

Bolt links and riveted joints, although widely used in aerospace and other mechanical systems, are susceptible to stress concentrations and fatigue cracks, which are undesirable. The flexible rosette eddy current sensor is typically used for the structural monitoring of bolt connections and riveted joints. This study proposes a method to improve the sensitivity of a flexible rosette eddy current sensor by reducing the cloud zenith angle of the pickup coil. First, the effect of the cloud zenith angle upon the sensitivity of the flexible rosette eddy current sensor is analyzed theoretically; the results show that a larger cloud zenith angle corresponds to a larger background signal. This diminishes the relative rate of change of the crack signal when the sensitivity of the sensor is evaluated based upon the maximum rate of change of the output. Therefore, the sensitivity is optimized by reducing the cloud zenith angle. Subsequently, through simulation and experimental methods, the relationship between sensor sensitivity and cloud zenith angle was studied. The results indicate that the cloud zenith angle significantly affects the sensitivity and that reducing the cloud zenith angle effectively reduces the background and improves the sensitivity. [ABSTRACT FROM AUTHOR]

Motivated by operational problems in click-and-collect systems, such as curbside pickup programs, we study a joint admission control and capacity allocation problem. We consider systems where customers have preferred service delivery times and can be of different priority classes. The service provider can reject customers upon arrival or serve jobs via overtime when service capacity is insufficient. The service provider's goal is to find the minimum-cost admission and capacity allocation policy to dynamically decide when to serve and whom to serve. We model this problem as a Markov Decision Process and present structural results to partially characterize suboptimal solutions. We then develop a linear programming-based exact solution method using these results. We also present a problem-specific approximation method using a new state aggregation rule to address computational challenges faced due to large state and action spaces. Finally, we develop heuristic policies for large instances based on the behavior of optimal policies in small problems. We evaluate our methods through extensive computational experiments where we vary the service capacity, arrivals, associated service costs, customer segmentation, and order patterns. Our solution methods perform significantly better than several benchmarks in managing the tradeoff between the computation time and solution quality. [ABSTRACT FROM AUTHOR]

This study focuses on the lateral safety of autonomous vehicles. The aim is to provide greater safety margins for the motion controller under hazardous conditions by improving the planning methods. The proposed lateral planning method employs a hierarchical structure. First, a graph search method that considers road curvature is presented. This method benefits from the design of jump nodes and can generate a safe corridor in real-time by backtracking. Next, a concise and effective optimization problem is constructed in the Frenet frame. It is designed to optimize the path by incorporating the peak, integral, and differential of curvature into the objective function. By solving this problem using CasADi, the path within the safe corridor is obtained. Finally, the proposed planning method is combined with a model predictive motion controller and tested through simulation and experimentation on a real vehicle platform. This planning method has good scalability, adaptability, and real-time performance. Simulation and experimental results show that this method can help avoid exceeding lateral limits of road surface friction, improve path-following accuracy, and enhance the safety of autonomous vehicles in dangerous conditions. [ABSTRACT FROM AUTHOR]

Edge-cloud computing has been widely adopted to provision abundant resources for latency-sensitive and computation-intensive vehicular applications in Internet of vehicles (IoV), bringing more entertainment, security, and efficiency on the road. Generally, the applications in real world are composed of massive subtasks with dependent relationships which are commonly modelled as directed acyclic graphs (DAGs), and thus fine grained offloading and parallel computing are imperative during offloading to promote the quality of service. However, due to the diversity of DAG-based applications and the complexity of dynamic edge-cloud environment, the vehicle intelligent management system is incapable of scheduling offloading with effect, resulting in additional transmission latency and energy expenditure on wireless channels and backhaul links. To reduce application response time and meanwhile save the energy consumption, a markov decision process is formulated based on the fine grained offloading with the intention of obtaining an optimal policy. Besides, to make offloading more adaptive to various application scales, a learning-aided fine grained offloading for real-time applications, named LFGO, is designed with deep q-learning in edge-cloud empowered IoV. Eventually, experiments are conducted with generated DAGs based on real-world applications, covering a wide range of subtask numbers, transmission rate and computing capability, to verify the efficiency of LFGO. [ABSTRACT FROM AUTHOR]

In real-life, green logistics is prevalent with the advent of pollution reduction; therefore, electric vehicle routing problem (EVRP) gains more focus. However, nonlinear charging technique has not obtained adequate attention for EVRP with time windows. In this study, an improved differential evolution (IDE) algorithm is introduced to address a variant of EVRP, which involves time windows and partial recharging policy with nonlinear charging. In IDE, a productive approach is developed to instruct the electric vehicle to charge in advance. A modified crossover operator is proposed to make populations more diverse. Five local neighborhood operators and a simulated annealing algorithm are embedded to enhance search quality. Further, we generate 55 instances based on Solomon benchmark and Analysis of Variance is leveraged to manifest the efficacy. Similarly, three algorithms are selected for comparison, i.e., genetic algorithm, artificial bee colony algorithm, and adaptive large neighborhood search. Experimental comparisons reveal that IDE outperforms others. [ABSTRACT FROM AUTHOR]

Bike-sharing system has become an indispensable element of sustainable urban transportation, effectively resolving the "last mile" transportation challenge for city dwellers. A major daily operational task in these systems is planning a fleet to rebalance the bikes over time, ensuring the optimal availability of bikes and docks to users. Recycling is also a daily work with the an increase in the number of broken bikes. However, rebalancing or recycling operation is always regarded as an independent tasks. They are separately studied in existing papers. Thus, this paper develops an operational strategy for recycling broken bikes during the rebalancing process, and studies the combination of the station inventory and vehicle routing problems. First, an inventory routing model is constructed with the aim of minimizing the total costs including procurement, expected user loss, inventory and transportation costs. Then, a two-stage iterative algorithm is developed with both exact and heuristic algorithms. We use real-world data from Capital Bikeshare to test our proposed model and approach, which shows the two-stage iterative algorithm is efficient and outperforms existing solutions in reducing total costs. Finally, the sensitivity analysis is performed on key parameters such as the vehicle's capacity, unit penalty costs for customer dissatisfaction events, unit inventory holding costs and the observation period of rebalancing. It shows that enterprises can reduce the total cost by altering vehicle's capacity, reducing the unit inventory holding costs or changing the observation period of rebalancing. [ABSTRACT FROM AUTHOR]

This paper reviews the research methodologies used in earlier years on the benefits and traits reflected by multi-depot vehicle routing problem (MDVRP) instances and assesses the efficacy of various improvised techniques to improve the current recurrent problems in routing procedures. Management of logistics involves moving finished goods from depots to end-user clients. Routing and scheduling systems that are improved will be able to serve a more significant number of customers in a shorter amount of time while also increasing customer satisfaction. To thoroughly discuss the current state of MDVRP implementation in routing heuristics, an analysis of the selected approaches involving multi-depot task distribution under VRP incorporations is further extrapolated. These approaches address the most common routing issues involving constraints like cost optimality, time window impositions, and load capacity flexibility. Recent research focuses on the advantages, proficiency, problem magnitude, and adaptability in MDVRP. The MDVRP framework can still be significantly improved by reducing routing costs with efficient heuristics to generate optimized solutions. [ABSTRACT FROM AUTHOR]

This paper introduces the three‐dimensional case picking problem (3D‐CPP) and proposes a multistart biased‐randomized algorithm (BRA) to solve it. The 3D‐CPP combines two important topics in modern warehouse logistics: the pallet loading problem and the routing of pickers in manual warehouses. The proposed optimization procedure aims at minimizing the overall distance traveled by the pickers, and is achieved by combining a routing problem (i.e., the order in which picking positions are visited) with a loading problem (i.e., the way in which cases are placed onto the pallet). We also consider additional constraints regarding the weight, vertical support, and strength of the cases. In order to solve this problem, we first propose a constructive heuristic which combines routing and packing procedures. This initial heuristic is then extended into a multistart BRA by employing a skewed probability distribution to introduce a certain degree of randomness during the solution‐construction process. A series of computational experiments allow us to assess the quality of the proposed approach, through a comparison with other algorithms as well as using real‐life data provided by an industrial partner. [ABSTRACT FROM AUTHOR]

The Vehicle Routing Problem belongs to graph optimization and its goal is to find shortest routes visiting a given set of customers with additional constraints present. The article presents the ant colony optimization metaheuristic which solves vehicle routing problems and its real-life application in transport logistics (finding routes for delivery companies). The metaheuristic generated high-quality solutions (superior to compared methods). Our tool is flexible and enables us to solve various variants of routing problems so it is well suited to specific needs of transportation companies. [ABSTRACT FROM AUTHOR]

Understanding the connection between how consumers perceive sustainability and how they experience the offered products or services can make a big difference for companies to stay ahead of the competition. When companies work to make their products and services align with what their customers value, like being eco‐friendly and socially responsible, it may not only draw in new customers but also make the existing ones stick around. Using behavioral reasoning theory, we attempt to explore the impacts of perceived benefits and skepticism on attitude toward sustainability and the moderating role of customer experience on the relationship between these variables and loyalty. Findings (n = 660) showed that attitude toward sustainability mediates the relationship between perceived benefits, skepticism, and customer loyalty. Furthermore, our findings highlighted that customer experience moderates the relationship between attitude toward sustainability and loyalty. The details of the moderation analysis suggest that cognitive, affective, physical, and social experiences have a stronger effect than sensory experiences in reinforcing the impact of perceived benefits and attitude on consumer loyalty in a sustainability context. The article concludes with implications and research directions for further investigation. [ABSTRACT FROM AUTHOR]

The surge in online shopping has increased the demand for home delivery, leading to a shortage of delivery drivers. This situation compels logistics companies to devise efficient delivery routes, considering delivery times, number of vehicles, and fuel costs. This issue is called the Vehicle Routing Problem with Time Windows (VRPTW). Recent research indicates that the chaotic search (CS) method with adaptive penalty coefficients (APCs) can efficiently solve VRPTW. The CS method with APCs (CS-APC) achieves an efficient solution search by diversifying and centralizing solutions in accordance with the search situation. However, when the solution diversifies towards the end of the search, the variance of solutions obtained by CS-APC increases. In this study, we propose a CS method using APCs based on temperature annealing (APCT). The use of APCT strengthens solution centralization via the search time temperature, thereby improving the quality of solutions. Numerical experiments confirm that our proposed method finds solutions with fewer vehicles and shorter travel distances than when using the conventional method. [ABSTRACT FROM AUTHOR]

This article describes the development of a decision support tool for a Rich Vehicle Routing Problem (R-VRP) of a major European do-it-yourself (DIY) retailer. The tool enables more comprehensive and structured planning at the retailer and an average of 8% transportation cost savings, translating to total savings of more than € 1 million per year for this specific retailer compared with the status quo. This article describes the development of a decision support tool for a Rich Vehicle Routing Problem (R-VRP) of a major do-it-yourself (DIY) retailer supplying its stores across Europe from multiple depots. The retailer uses external logistic service providers (LSPs) for the delivery to its stores and has two modes to choose from. In the first mode, the retailer proposes delivery tours to LSPs for execution. These tours are billed according to a nonlinear tariff with volume discounts depending on the delivery zones visited and the load carried. The LSPs accept the retailer's tour proposal only if tour duration and distance restrictions are kept. The latter is ensured by a relative detour limit. In the second mode, the retailer assigns single shipments to common carriers that consolidate them with shipments from other customers and bill this based on load and destination. The resulting problem represents an open VRP with two delivery modes, carrier selection and a heterogeneous fleet. Multiple delivery modes are standard in DIY retailing and constitute a general industry problem. The literature on VRPs and current software applications in the industry predominantly considers modeling and solution approaches that rely on linear distance costs, neglecting that nonlinear zone-based tariffs with volume discounts are standard in the freight forwarding business. Our work addresses this issue by developing a decision support tool for the retailer based on an exact algorithm for solving R-VRPs with a nonlinear zone-based tariff scheme and a relative detour limit. The tool is based on an innovative three-component set partitioning algorithm working on a complete set of feasible tours to solve the problem. We show that our approach optimally solves the daily distribution problem of the industry partner with up to 150 stores. Furthermore, implementing the tool enables more comprehensive and structured planning for the retailer and an average of 8% transportation cost savings, translating to total savings of more than €1 million per year for this specific retailer compared with the status quo. History: This paper was refereed. [ABSTRACT FROM AUTHOR]

The path planning problem is an important issue in maritime search and rescue. This paper models the path planning problem as a dynamic vehicle routing problem. It first designs a dynamic generator that transforms the existing benchmark sets for the static vehicle routing problem into dynamic scenarios. Subsequently, it proposes an effective Dynamic Ant Colony Optimization (DACO) algorithm, whose novelty lies in that it dynamically adjusts the pheromone matrix to efficiently handle customers' changes. Moreover, DACO incorporates simulated annealing to increase population diversity and employs a local search operator that is dedicated to route modification for continuous performance maximization of the route. The experimental results demonstrated that the proposed DACO outperformed existing approaches in generating better routes across various benchmark sets. Specifically, DACO achieved significant improvements in the route cost, serviced customer quantity, and adherence to time window requirements. These results highlight the superiority of DACO in the dynamic vehicle routing problem, providing an effective solution for similar problems. [ABSTRACT FROM AUTHOR]

This paper presents a novel enhanced adaptive-convergence in Harris' hawks optimization algorithm (EAHHO). In EAHHO, considering that Harris' hawks will adopt different perching strategies and chasing styles according to the value of the escaping energy parameter E, nonlinear adaptive-convergence factor a is designed and adjusted to enhance the convergence and robustness of the algorithm. Moreover, the convergence and stability of EAHHO are proved mathematically by using the Markov chain theory and Lyapunov stability theory respectively. Moreover, numerical simulation results of 14 HHOs with different nonlinear convergence factors on 23 benchmark functions show that the nonlinear convergence factor of EAHHO is applicable to challenging problems with unknown search spaces, and the comparisons with the selected well-established algorithms on 56 test functions demonstrate that EAHHO performs competitively and effectively. Finally, the experiment results show that EAHHO algorithm also has a good performance to solve the optimization problems with relatively high dimensions and graph size of Internet of Vehicles routing problem. [ABSTRACT FROM AUTHOR]

The Vehicle Routing Problem is about optimizing the routes of vehicles to meet the needs of customers at specific locations. The route graph consists of depots on several levels and customer positions. Several optimization methods have been developed over the years, most of which are based on some type of classic heuristic: genetic algorithm, simulated annealing, tabu search, ant colony optimization, firefly algorithm. Recent developments in machine learning provide a new toolset, the rich family of neural networks, for tackling complex problems. The main area of application of neural networks is the area of classification and regression. Route optimization can be viewed as a new challenge for neural networks. The article first presents an analysis of the applicability of neural network tools, then a novel graphical neural network model is presented in detail. The efficiency analysis based on test experiments shows the applicability of the proposed NN architecture. [ABSTRACT FROM AUTHOR]

Recognizing consumer interests and satisfaction is crucial for organizations to thrive in a competitive market. A strong marketing strategy aids companies in reaching customers and building a reputation for their products. Presently, numerous internet platforms employ recommender systems on a commercial basis. Customer preferences are generally obtained behaviours of users from online shopping which is used to recommend the products. Deep Learning (DL) models have been used for efficient customer preference recommendation, but these models don't consider secondary information such as Knowledge Graph (KG) and comment information. Hence, in this paper, Time Aware Attention and KG embedded Deep Network for Recommendation (TAK-DepNR) is proposed by combining Convolutional Neural Network (CNN) and Graph Convolutional Network (GCN). In this method, the user similarity, item similarity and latent period are modelled using Matrix Factorization (MF) model. The MF generates long and short preferences which are then fed into the CNN and GCN models to produce dynamic user preferences. The CNN extracts higher-level characteristics among the user and item from MF, then reduces to lower-order features. The GCN aids to train the interpretation of each node and encodes the KG based Global Convolutional Feature Map (KGGCFM) for CNN through the shared features. This creates a major link between the products and allowing for more extensive item feature description for user preference graph. The CNN will be integrated with GCN using its squeezed units to learn the high-level feature relations between recommendation systems and KG entities. Finally, dynamic user preferences from CNN and GCN are passed into Fully Connected (FC) layer constructed network to recommend the items. The experimental results show that the TAK-DepNR realizes average precision of 89% and 88% compared to the other models like Immersive Graph Neural Network (IGNN), Attentional Factorization Machine with Review- Based User-Item Interaction (AFMRUI), Item Collaborative Filtering with RNN (ICFRNN), Deep Reinforcement Recommender System with Maximum pooling layers (DRR-Max) and Sentiment Analysis with Bidirectional Long Short Term Memory (SA-BiLSTM) on Amazon Digital Music Dataset and Book Crossing Dataset. [ABSTRACT FROM AUTHOR]

Machine learning techniques have advanced rapidly, leading to better prediction accuracy within a short computational time. Such advancement encourages various novel applications, including in the field of operations research. This study introduces a novel way to utilize regression machine learning models to predict the objectives of vehicle routing problems that are solved using a genetic algorithm. Previous studies have generally discussed how (1) operations research methods are used independently to generate optimized solutions and (2) machine learning techniques are used independently to predict values from a given dataset. Some studies have discussed the collaborations between operations research and machine learning fields as follows: (1) using machine learning techniques to generate input data for operations research problems, (2) using operations research techniques to optimize the hyper-parameters of machine learning models, and (3) using machine learning to improve the quality of operations research algorithms. This study differs from the types of collaborative studies listed above. This study focuses on the prediction of the objective of the vehicle routing problem directly given the input and output data, without optimizing the problem using operations research algorithms. This study introduces a straightforward framework that captures the input data characteristics for the vehicle routing problem. The proposed framework is applied by generating the input and output data using the genetic algorithm and then using regression machine learning models to predict the obtained objective values. The numerical experiments show that the best models are random forest regression, a generalized linear model with a Poisson distribution, and ridge regression with cross-validation. [ABSTRACT FROM AUTHOR]

In metropolitan cities, it is very complicated to govern the optimum routes for garbage collection vehicles due to high waste production and very dense population. Furthermore, wrongly designed routes are the source of wasting time, fuel and other resources in the collection of municipal trash procedure. The Vehicle Routing Problem (VRP) published between 2011 and 2023 was systematically analysed. The majority of the surveyed research compute the waste collecting problems using metaheuristic approaches. This manuscript serves two purposes: first, categorising the VRP and its variants in the field of waste collection; second, examining the role played by most of the metaheuristics in the solution of the VRP problems for a waste collection. Three case study of Asia continent has been analysed and the results show that the metaheuristic algorithms have the capability in providing good results for large-scale data. Lastly, some promising paths ranging from highlighting research gap to future scope are drawn to encourage researchers to conduct their research work in the field of waste management route problems. [ABSTRACT FROM AUTHOR]

This study delves into the critical need for generating real-world compatible data to support the application of deep reinforcement learning (DRL) in vehicle routing. Despite the advancements in DRL algorithms, their practical implementation in vehicle routing is hindered by the scarcity of appropriate real-world datasets. Existing methodologies often rely on simplistic distance metrics, failing to accurately capture the complexities inherent in real-world routing scenarios. To address this challenge, we present a novel approach for generating real-world compatible data tailored explicitly for DRL-based vehicle routing models. Our methodology centers on the development of a spatial data extraction and curation tool adept at extracting geocoded locations from diverse urban environments, encompassing both planned and unplanned areas. Leveraging advanced techniques, the tool refines location data, accounting for unique characteristics of urban environments. Furthermore, it integrates specialized distance metrics and location demands to construct vehicle routing graphs that represent real-world conditions. Through comprehensive experimentation on varied real-world testbeds, our approach showcases its efficacy in producing datasets closely aligned with the requirements of DRL-based vehicle routing models. It's worth mentioning that this dataset is structured as a graph containing location, distance, and demand information, with each graph stored independently to facilitate efficient access and manipulation. The findings underscore the adaptability and reliability of our methodology in tackling the intricacies of real-world routing challenges. This research marks a significant stride towards enabling the practical application of DRL techniques in addressing real-world vehicle routing problems. [ABSTRACT FROM AUTHOR]

The proliferation of hydrogen fuel cell vehicles calls for effective planning of hydrogen supply facilities. This paper focuses on renewable energy-based distributed hydrogen supply networks (DHSNs), with on-site production and vehicle-based transport. To explore the energy synergism effect, we propose multinetwork constrained planning of hydrogen-power supplying facilities. Considering the double-layer coupling mechanism (DCM), multiple DHSN equipment planning is coordinated with the generation planning of the power distributed networks (PDN). Firstly, the DCM is proposed considering structured multi-component equipment, inter-layer hydrogen couplings, and cross-network power couplings. Secondly, to formulate the DCM, we develop a structured deployment model for DHSN equipment to enhance system integrality and non-redundancy. Specially, to release more flexibilities, inter-layer transport is modeled by proposing a spatiotemporal extended vehicle routing problem model incorporating multiple loading stations with trip coordination. Thirdly, a planning method is proposed to coordinate the planning of hydrogen-power supply facilities in coupled networks, incorporating the double-layer coupling constraints, station operation constraints, and PDN constraints. Test systems are employed to verify the effectiveness of the proposed method. • The double-layer coupling mechanism is proposed for distributed hydrogen supply network (DHSN) and power distribution network. • A structured deployment model is proposed for the DHSN equipment. • Inter-layer hydrogen transport is modeled by extended vehicle routing. • A coordinated planning method is established for the distributed generators and DHSN facilities. [ABSTRACT FROM AUTHOR]

Logistics and transportation industry is not only a major energy consumer, but also a major carbon emitter. Developing green logistics is the only way for the sustainable development of the logistics industry. One of the main factors of environmental pollution is caused by carbon emissions in the process of vehicle transportation, and carbon emissions of vehicle transportation are closely related to routing, road conditions, vehicle speed, and speed fluctuations. The low-carbon vehicle routing problem with high granularity time-dependent speeds, speed fluctuations, road conditions, and time windows is proposed and formally described. In order to finely evaluate the effects of vehicle speed and speed fluctuations on carbon emissions, a graph convolutional network (GCN) is used to predict the high granularity time-dependent traffic speeds. To solve this complicated low-carbon vehicle routing problem, a hybrid genetic algorithm with adaptive variable neighborhood search is proposed to obtain vehicle routing with low carbon emissions. Finally, this method is validated using a case study with the logistics and traffic data in Jingzhou, China, and also the results show the effectiveness of this proposed method. [ABSTRACT FROM AUTHOR]

In this paper, we investigate a scenario in which protected and unprotected services coexist in an elastic optical network under dynamic traffic. In the investigated scenario, unprotected services can reuse the reserved idle bandwidth to provide protection to the protected services. Under this scenario, we propose a new heuristic algorithm that enables such reuse as well as define and introduce a new assignment problem in elastic optical networks, named a Transmission Spectrum Assignment (T-SA) problem. In this paper, we consider a scenario in which services may be routed using the multipath routing approach. Additionally, protection using bandwidth squeezing is also considered. We assess our proposal through simulations on three different network topologies and compare our proposal against the classical protection approach, in which bandwidth reuse is not allowed. For the simulated range of network loads, the maximum (minimum) blocking probability reduction obtained by our proposal is approximately 48% (10%) in the European topology, 46% (7%) in the NSFNET topology, and 32% (6%) in the German topology. [ABSTRACT FROM AUTHOR]

A battery track engineering vehicle faces challenges such as derailment and other safety concerns when navigating an R20m minimum radius curve, primarily owing to its low vertical and horizontal stabilities. To address these issues, a methodology integrating genetic optimization algorithms with a rigid and flexible coupled multi-body dynamics simulation is proposed to optimize the primary suspensions of the bogie of the vehicle. Initially, a multi-objective optimization model combining rigid and flexible coupled multi-body dynamics of battery track engineering vehicles with a genetic optimization algorithm was formulated. Subsequently, the optimal Latin hypercube design was applied to analyze the sensitivity of vertical and horizontal stability to various suspension parameters. Finally, a non-dominated sorting genetic algorithm (NSGA-II) and an archive-based micro genetic algorithm (AMGA) were applied to optimize the primary suspensions to enhance stability. Consequently, a set of optimal suspension parameter combinations was obtained. A notable enhancement was observed in the lateral stability of the optimized battery track engineering vehicles by 23.33% and in the vertical stability by 3.5% when traversing the R20m minimum radius curve, thereby establishing a theoretical foundation for further improving the running safety of railway vehicles and resolving the shortcomings of less research on the smallest radius curve. [ABSTRACT FROM AUTHOR]

The split delivery vehicle routing problem (SDVRP) is a classic combinatorial optimization problem, which is usually solved using a heuristic algorithm. The ant colony optimization algorithm is an excellent heuristic algorithm that has been successfully applied to solve various practical problems, and it has achieved good results. However, in the existing ant colony optimization algorithms, there are issues with weak targeting of different customer selection strategies, difficulty in balancing convergence speed and global search ability, and a predisposition to become trapped in local optima. To solve these problems, this paper proposes an improved ant colony algorithm (IACA). First, in terms of customer point selection, the initial customer and noninitial customer selection strategies are proposed for different customers, and the adaptive selection threshold is designed. Second, in terms of pheromone processing, an initial pheromone distribution method based on a greedy strategy, a pheromone backtracking mechanism, and an adaptive pheromone volatile factor are proposed. Finally, based on the 2-opt local search method, vehicle path self-search and intervehicle path search are proposed to further improve the quality of the solution. This paper tests the performance of the IACA on datasets of different scales. The experimental results show that compared with the clustering algorithm, artificial bee colony algorithm, particle swarm optimization algorithm, traditional ant colony algorithm, and other algorithms, the IACA can achieve more competitive results. Specifically, compared to the path length calculated by other algorithms, the path length calculated by IACA decreased by an average of 1.58%, 4.28%, and 3.64% in small, medium, and large-scale tests, respectively. [ABSTRACT FROM AUTHOR]

In the last two decades or so, a large number of image ciphers have been written. The majority of these ciphers encrypt only one image at a time. Few image ciphers were written which could encrypt multiple images in one session. The current era needs speedy multiple image ciphers to address its varied needs in different settings. Motivated by this dictation, the current study has ventured to write a multi-image cipher based on the fleet of pawns walking in the large hypothetical chessboard. This walk of pawns on the chessboard has been ingeniously linked with transferring the pixels from the plain image to the scrambled image. The confusion effects have been realized through the XOR operation between the scrambled image and the key image. The plaintext sensitivity has been incorporated by embedding the SHA-384 hash codes of the given large combined plain image. Moreover, the Henon map has been employed to spawn the streams of random numbers. Besides, Blum Blum Shub random number generator has been used to further cement the security of the proposed cipher. We got a computational time of 0.2278 seconds and an encryption throughput of 5.5782 MBit/seconds by using the four images with a size of 256×256. Apart from that, the information entropy gained is 7.9993. Lastly, the cipher has been subjected to an array of validation metrics to demonstrate its aversion to the myriad threats from the cryptanalysis savvy. We contend that the proposed work has great potential for some real-world applications. [ABSTRACT FROM AUTHOR]