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NSGAII enhanced with a local search for the vehicle routing problem with time windows and synchronization constraints

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IFAC-PapersOnLine 2016年第12期49卷 1198-1203页

作者： Haddadene, S.R. Ait Labadie, N. Prodhon, C. ICD-LOSI University of Technology of Troyes CNRS-UMR 6281 12 Rue Marie Curie Troyes CedexCS42060-10004 France

In the field of Home Health Care (HHC), the vehicle routing problem with time windows, synchronization, and precedence constraints (VRPTW-SP) involves finding the lowest-cost set of routes to visit patients requesting one or more services in a specific time window and during a fixed time service. Each patient has preference weights associated to the vehicles who are available to provide the requested service. To solve the problem, different variations for multi-objective met a-heuristic based on the Non-dominated Sorting Genetic Algorithm (NSGAII) are proposed. The considered objectives are the minimization of travel costs and the maximization of patients preferences. This problem was solved in a previous work as a single-objective variant, despite the conflicting nature of these two criteria. Numerical results are presented for instances with up to 73 patients. Metrics such as spacing, hyper-volume and the number of non dominated solutions are used to measure the quality of solutions. © 2016

关键词： Problem solving Genetic algorithms Home health care Local search (optimization) Multiobjective optimization synchronization Vehicle routing Vehicles Met a heuristics Non dominated sorting genetic algorithms Nondominated solutions Precedence constraints Quality of solution Routing problems synchronization constraints Vehicle routing problem with time windows

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NSGAII enhanced with a local search for the vehicle routing problem with time windows and synchronization constraints

NSGAII enhanced with a local search for the vehicle routing ...

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8th IFAC Conference on Manufacturing Modelling, Management and Control (MIM)

作者： Haddadene, S. R. Ait Labadie, N. Prodhon, C. Univ Technol Troyes CNRS UMR 6281 ICD LOSI 12 Rue Marie CurieCS 42060 F-10004 Troyes France

In the field of Florae Health Car vehicle rot problem time windows, synchronization, and precedence constraints (VRPTW-SP) involves finding- the I cost set of routes to visit patients requesting one or more services in a specific time window are during a fixed time service. Each patient has preference weights associated to the vehicles who are available to provide the requested service. To solve the problem, different variations for multi objective meta-heuristic based on the Non-dominated Sorting Genetic Algorithm (NSGAII) are proposed. The considered objectives are the minimization of travel costs and the maximization of patients preferences. This problem was solved in a previous work as a single-objective variant, despite the conflicting nature of these two Criteria Numerical results are presented for instances with up to 73 patients. Metrics such as spacing, hyper-volume and the number of non dominated solutions are used to measure the quality of solutions. (C) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All right reserved.

关键词： Multi-Objective Optimization Meta-heuristics Routing Problem Home Health Care synchronization constraints Precedence constraints

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A Robust Home Health Care Scheduling and Routing Approach with Time Windows and synchronization constraints Under Travel Time and Service Time Uncertainty

A Robust Home Health Care Scheduling and Routing Approach wi...

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IFIP WG 5.7 International Conference on Advances in Production Management Systems (APMS)

作者： Makboul, Salma Kharraja, Said Abbassi, Abderrahman Alaoui, Ahmed El Hilali SMBA Univ Modelling & Math Struct Lab FST Fez Fes Morocco Univ Lyon LASPI UJM St Etienne Roanne France Fac Sci Marrakech Morocco Euromed Univ 32 Rue Meknes Fes Morocco

ISBN: (纸本)9783030859022;9783030859015

Home health care (HHC) services represent a set of medical services given to patients at their homes. The patients require a set of care that must be coordinated and treated by skilled caregivers corresponding to their needs. This study proposes an HHC routing and assignment approach based on a mixed-integer linear programming model that aims to minimize total route cost. The HHC approach takes into account a set of HHC specific constraints and criteria. Secondly, we propose a new robust counterpart HHC model under uncertainty based on the well-known budgeted uncertainty set. The robust counterpart HHC model deals with travel and service times uncertainty. The computational results compare the deterministic model with its robust counterpart model. The small and medium instances have been solved using TSP benchmarks with specific data concerning HHC problems. The models have been implemented using ILOG CPLEX Optimization Studio. The computational results of small and medium instances indicated the efficiency of the proposed approach. Robustness analysis of the obtained results was conducted using a Monte Carlo simulation and indicated the price of robustness. The increase of route cost in comparison with the risk of infeasibility shows the importance of the designed robust routes for HHC routing and scheduling problems.

关键词： Home health care Uncertainty Mixed integer linear programming Routing problem Precedence constraints synchronization constraints

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A GRASP x ILS for the vehicle routing problem with time windows, synchronization and precedence constraints

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EXPERT SYSTEMS WITH APPLICATIONS 2016年 66卷 274-294页

作者： Haddadene, Syrine Roufaida Ait Labadie, Nacima Prodhon, Caroline Univ Technol Troyes CNRS UMR 6281 ICD LOSI 12 Rue Marie CurieCS 42060 F-10004 Troyes France

Efficient use of resources while ensuring quality services points the attention of Home Health Care structures (HHC). HHC structures propose keeping at home patients who do not necessarily need full hospitalization, and enabling people who suffered serious illnesses to follow the care from their own home. Habitually, asked services have to be performed at specific times, and may require the intervention of several qualified caregivers related by precedence constraints. These structures have the concern to reduce product consumption costs, limit losses and provide high quality services. Their main budgetary item is defined by the personal salary, which is incompressible. So, costs should be reduced on other posts. In this context, personal travel cost has a major importance in the spending of the institutions, which seems necessary to optimize. Moreover, patient satisfaction is also a significant criterion in improving the service quality of such structures. Therefore, developing an effective caregivers planning require the use of optimization methods and decision tools. In this article, this issue is modeled as a particular variant of vehicle routing problem with time windows and timing constraints, where some patients ask for more than one visit simultaneously or in a given priority order, called as the VRPTW-SP. Timing constraints handled in this paper make the problem realistic that are more difficult to solve than VRPTW. The VRPTW-SP is a challenging and novel optimization problem, whose objective is the minimization of the caregivers travel cost added to the non preferences toward caregivers. To solve this problem, a Mixed Integer Linear Program, a greedy heuristic, two local search strategies and three metaheuristics are proposed, one being a hybridization of the two others. Experiments are conducted on new instances derived from the literature. As the metaheuristics share the same components the positive contribution of the hybridization is proved on the VRPT

关键词： Vehicle routing problem synchronization constraints Precedence constraints MILP Metaheuristic

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Rehabilitation therapy scheduling accounting for teaming requirements and therapist shortages: a branch and price approach

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FLEXIBLE SERVICES AND MANUFACTURING JOURNAL 2025年 1-32页

作者： Kling, Sebastian Schiffels, Sebastian Brunner, Jens O. Univ Augsburg Fac Business & Econ Augsburg Germany Tech Univ Denmark Dept Technol Management & Econ Kongens Lyngby Denmark Ctr Excellence Healthcare Operat Planning Next Generat Technol Hillerod Denmark

Physical therapy in acute care hospitals plays an important role for the rehabilitation of patients. Nevertheless, the profession must deal with staff shortages caused by a lack of qualified employees and stress-induced absenteeism. Both are results of high physical and mental workloads as well as a lack of employee retention strategies. A therapist shortage negatively affects the total number of appointments the department can fulfill daily. Furthermore, severe cases where patients require two therapists at the same time are common in acute care hospitals and contribute to the scheduling complexity. Here, one therapist takes charge of the appointment (lead), while a second therapist fulfills a support function role. This paper develops a multi-criteria optimization model for the daily rehabilitation therapy scheduling problem subject to teaming aspects and appointment priorities. We minimize preference penalties for lead and support visits and the total priority-based violation for unscheduled appointments. The problem is modeled as a vehicle routing problem with time windows and synchronization constraints. We solve the problem using a branch-and-price approach with different visit clustering methods and speed-up techniques. Computational results show the effectiveness of a randomized greedy heuristic implemented to enhance performance for generating new columns. Besides, a problem-specific clustering approach is integrated to speed up subproblems' solution times. Our results show its high effectiveness when compared to a state-of-the-art approach derived from literature.

关键词： OR in health services Physical therapy Vehicle routing problem Time windows synchronization constraints Workforce shortages

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Local Search Analysis for a Vehicle Routing Problem with synchronization and Time Windows constraints in Home Health Care Services

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IFAC-PapersOnLine 2016年第12期49卷 1210-1215页

作者： En-nahli, Laila Afifi, Sohaib Allaoui, Hamid Nouaouri, Issam EA 3926 BéthuneF-62400 France

This paper presents the vehicle routing problem with time windows and synchronization constraints (VRPTWSyn) in the context of home health care services. We propose a new approach for solving the considered problem. To build an initial solution, we develop a constructive heuristic based on the best insertion heuristic, taking in consideration the synchronization constraints. In order to improve the initial solution, we propose an Iterated Local Search (ILS) metaheuristic coupled with a variant of the Random Variable Neighborhood Descent method (RVND) which uses a random ordering of neighborhoods in local search phase (RVND-ILS algorithm). Computational experiments have been conducted on 15 benchmark instances from the literature. The proposed algorithm, obtains solutions as good as any reported results. In this paper, we propose many neighborhood structures for the problem, and a study of these operators has been conducted as well. © 2016

关键词： Home health care Benchmarking Decision support systems Local search (optimization) Problem solving synchronization Vehicle routing best insertion Computational experiment Iterated local search Routing problems synchronization constraints Variable neighborhood descents Vehicle routing problem with time windows Vehicle Routing Problems

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A matheuristic solution for efficient scheduling in dynamic truck-drone collaboration

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EXPERT SYSTEMS WITH APPLICATIONS 2025年 267卷

作者： Zhao, Jinqiu Long, Yuying Xie, Binglei Xu, Gangyan Liu, Yongwu Harbin Inst Technol Shenzhen Sch Architecture Shenzhen 518000 Guangdong Peoples R China Hong Kong Polytech Univ Fac Engn Dept Aeronaut & Aviat Engn Hong Kong 999077 Peoples R China

Unmanned aerial vehicles (UAVs), or drones, have great potential for emergency response operations in areas with vulnerable road networks and infrastructure. However, the low battery capacity restricts their quick, cost-effective, and efficient aerial transportation capabilities. To overcome this drawback, hybrid systems that combine trucks and drones have emerged as a promising solution. Nevertheless, the fixed- binding mode between trucks and drones inmost studies tends to impair efficiency by limiting drones' operational flexibility. This paper investigates a dynamic truck-drone collaboration (DTDC) strategy for efficient and flexible emergency response. This strategy enables drones to dynamically change take-off and landing locations on different trucks, which is beneficial in emergency scenarios with common road network disruptions. Despite its advantages, the DTDC strategy introduces additional complexity to the scheduling problem, resulting in a time-consuming solution. To enhance solution efficiency and improve the application prospects of this strategy, we propose a matheuristic to decouple DTDC's multiple synchronization constraints, separating the scheduling problem into three decision-making processes: demand allocation, truck routing, and drone scheduling. Additionally, two alternative matheuristic algorithms are designed to target accuracy and computing efficiency, respectively. The empirical results indicate that the proposed heuristics outperform the state-of-the-art solver and several metaheuristics. A sensitivity analysis confirms that improvements in drone endurance and the strategic reservation of drone parking slots on trucks can significantly improve the DTDC strategy's performance.

关键词： Vehicle routing problem with drone Truck-drone collaboration synchronization constraints Matheuristic Column generation

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Reasoning about synchronization in GALS systems

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FORMAL METHODS IN SYSTEM DESIGN 2006年第2期28卷 153-169页

作者： Chakraborty, Supratik Mekie, Joycee Sharma, Dinesh K. Indian Inst Technol Bombay 400076 Maharashtra India

Correct design of interface circuits is crucial for the development of System-on-Chips (SoC) using off-the-shelf IP cores. For correct operation, an interface circuit must meet strict synchronization timing constraints, and also respect sequencing constraints between events dictated by interfacing protocols and rational clock relations. In this paper, we propose a technique for automatically analyzing the interaction between independently specified synchronization constraints and sequencing constraints between events. We show how this analysis can be used to derive delay constraints for correct operation of interface circuits in a GALS system. Our methodology allows an SoC designer to mix and match different interfacing protocols, rational clock relations and synchronization constraints for communication between a pair of modules, and automatically explore their implications on correct interface circuit design.

关键词： symbolic timing analysis synchronization constraints sequencing constraints GALS systems multi-clocked systems symbolic delay constraints

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Improving the State Space Computation of the Time Stream Petri Nets Model

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COMPUTER JOURNAL 2015年第7期58卷 1607-1627页

作者： Abdelli, Abdelkrim USTHB Univ LSI Lab Dept Comp Sci Babezzouar Algiers Algeria

An enumerative technique is presented allowing the reachability analysis of weakly synchronous systems modeled using time stream Petri net (TSPN). In a TSPN, time constraints are associated with incoming arcs, whereas synchronization rules are associated with transitions, thus allowing the violation of time constraints. We propose an approach to contract the TSPN state space by building its state class graph. Each class therein is a pair (M, D), where M is a marking and D is a system that can be encoded in a difference bound matrix, as long as no arc's time constraint violation is reported. Hence, each reachable class is computed by applying an optimal algorithm in a square complexity time. For this effect, efficient conditions for the consistency, firing and equivalence tests are provided to ensure a finite graph construction when the model is bounded. Finally, in order to validate our approach, experimental results are reported.

关键词： weakly synchronous systems time stream petri net state class graph lip synchronization multimedia systems synchronization constraints

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The Tiny-Tasks Granularity Trade-Off: Balancing Overhead Versus Performance in Parallel Systems

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2023年第4期34卷 1128-1144页

作者： Bora, Stefan Walker, Brenton Fidler, Markus Leibniz Univ Hannover Inst Commun Technol Hannover 30167 Germany

of parallel processing systems typically assume that one has l workers and jobs are split into an equal number of k = l tasks. Splitting jobs into k > l smaller tasks, i.e. using tiny tasks, can yield performance and stability improvements because it reduces the variance in the amount of work assigned to each worker, but ask increases, the overhead involved in scheduling and managing the tasks begins to overtake the performance benefit. We perform extensive experiments on the effects of task granularity on an Apache Spark cluster, and based on these, develop a four parameter model for task and job overhead that, in simulation, produces sojourn time distributions that match those of the real system. We also present analytical results which illustrate how using tiny tasks improves the stability region of split-merge systems, and analytical bounds on the sojourn and waiting time distributions of both split-merge and single-queue fork-join systems with tiny tasks. Finally we combine the overhead model with the analytical models to produce an analytical approximation to the sojourn and waiting time distributions of systems with tiny tasks which include overhead. We also perform analogous tiny-tasks experiments on a hybrid multi-processor shared memory system based on MPI and OpenMP which has no load-balancing between nodes. Though no longer strict analytical bounds, our analytical approximations with overhead match both the Spark and MPI/OpenMP experimental results very well.

关键词： Task analysis Sparks Servers Analytical models Cluster computing Parallel processing synchronization Network calculus parallel processing performance bounds processing overhead Spark synchronization constraints task granularity tiny-tasks

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