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Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Reinforcement Learning For Zone Based Multiagent Pathfinding Under Uncertainty, Jiajing Ling, Tarun Gupta, Akshat Kumar
Reinforcement Learning For Zone Based Multiagent Pathfinding Under Uncertainty, Jiajing Ling, Tarun Gupta, Akshat Kumar
Research Collection School Of Computing and Information Systems
We address the problem of multiple agents finding their paths from respective sources to destination nodes in a graph (also called MAPF). Most existing approaches assume that all agents move at fixed speed, and that a single node accommodates only a single agent. Motivated by the emerging applications of autonomous vehicles such as drone traffic management, we present zone-based path finding (or ZBPF) where agents move among zones, and agents' movements require uncertain travel time. Furthermore, each zone can accommodate multiple agents (as per its capacity). We also develop a simulator for ZBPF which provides a clean interface from the …
Online Traffic Signal Control Through Sample-Based Constrained Optimization, Srishti Dhamija, Alolika Gon, Pradeep Varakantham, William Yeoh
Online Traffic Signal Control Through Sample-Based Constrained Optimization, Srishti Dhamija, Alolika Gon, Pradeep Varakantham, William Yeoh
Research Collection School Of Computing and Information Systems
Traffic congestion reduces productivity of individuals by increasing time spent in traffic and also increases pollution. To reduce traffic congestion by better handling dynamic traffic patterns, recent work has focused on online traffic signal control. Typically, the objective in traffic signal control is to minimize expected delay over all vehicles given the uncertainty associated with the vehicle turn movements at intersections. In order to ensure responsiveness in decision making, a typical approach is to compute a schedule that minimizes the delay for the expected scenario of vehicle movements instead of minimizing expected delay over the feasible vehicle movement scenarios. Such …
Review On Agv Scheduling Optimization, Jianlin Fu, Hengzhi Zhang, Zhang Jian, Liangkui Jiang
Review On Agv Scheduling Optimization, Jianlin Fu, Hengzhi Zhang, Zhang Jian, Liangkui Jiang
Journal of System Simulation
Abstract: AGV scheduling plays an important role in improving the efficiency and reducing manufacturing cost, but it is also a very complex combinatorial optimization procedure. AGV scheduling optimization is divided into three types, AGV static scheduling, AGV dynamic scheduling and AGV simultaneous scheduling with other resources scheduling. Various methods are summarized and listed, including traditional analysis method, modeling and simulation method, intelligent optimization algorithm and hybrid optimization method, and the advantages and disadvantages of each method are also analyzed. The deficiencies of AGV scheduling research are pointed out and the research directions for future are presented.
Research Overview On Modeling And Solution Of Aerospace Tt&C Scheduling Problem, Qingqing Yan, Huairong Shen, Qiongling Shao
Research Overview On Modeling And Solution Of Aerospace Tt&C Scheduling Problem, Qingqing Yan, Huairong Shen, Qiongling Shao
Journal of System Simulation
Abstract: The research of Aerospace TT&C Scheduling (ATT&CS) is very important, because of its support for TT&C scheme decision-making and TT&C resource net constructing. The classification and resolution flow of the ATT&CS problem were introduced. Then, the modeling methods and related key techniques, such as designing of object function, analysis of constraints, and priority determining, were analyzed. The solving algorithms and conflict resolution methods were summed up, and the major categories of algorithm were evaluated. The main content of scheduling evaluation research was summarized. The possible future researches for related techniques were discussed based on the analysis of development and …
Simulation And Optimization For Bulk Terminal Yard Scheduling, Dongbo Hu, Li Pan, Binbin Zhang, Guozhi Liang
Simulation And Optimization For Bulk Terminal Yard Scheduling, Dongbo Hu, Li Pan, Binbin Zhang, Guozhi Liang
Journal of System Simulation
Abstract: Yard is the central part of the operation process of the whole terminal. In fact, the operation of lots of bulk terminal is unscientific, which severely restricts the turnover efficiency and the throughput of the terminal. Taking the coal terminal as an example and based on its operation process, the dispatching simulation model involving all parts of the operation was established and the rules of use of the yard grids was brought forward. By optimizing the operation strategy and related parameters, it is significant to improve the input quantity of bulk terminal and the turnover efficiency.
Modeling And Simulation On Railway Bulk Oil Transit Operations, Jingheng Ma, Xingchang Liu, Youhong Fan, Kang Jin
Modeling And Simulation On Railway Bulk Oil Transit Operations, Jingheng Ma, Xingchang Liu, Youhong Fan, Kang Jin
Journal of System Simulation
Abstract: The railway bulk oil transit operation is a hybrid (discrete/continuous) system because of the main body of the continuous flow oil and a variety of discrete events. According to the system’s characteristics of complex process, great difficulty, high risk, the oil transit operation model was established based on discrete rate simulation and system’s continuity, predict events, emergencies were analyzed. The model was converted into linear programming, the effective rate was calculated under constraints, and the operation process and event scheduling was simulated. It was verified that the model is feasible. By obtaining the dynamic behavior and real-time data, its …
Research On Modeling And Scheduling Of Cluster Tools With Reentrant Process, Chunrong Pan, Li Liang
Research On Modeling And Scheduling Of Cluster Tools With Reentrant Process, Chunrong Pan, Li Liang
Journal of System Simulation
Abstract: Cluster tools reconfigured are increasingly adopted in wafer fabrication. With single-wafer processing technology, the productivity and quality of semiconductor manufacturing have been improved. The configurations of cluster tools and constraints of operation processes were proposed. Due to the increase of processing requirements of wafer revisiting, the scheduling of cluster tools becomes more complicated. Thus, modeling, performance analyzing and scheduling of cluster tools with reentrant process were reviewed. Meanwhile, an illustrative example was given to show the feasibility of simulation scheduling. By analyzing the advantages and disadvantages of research methods available, approaches and future directions which would be effective for …
Adaptive Large Neighborhood Search For Vehicle Routing Problem With Cross-Docking, Aldy Gunawan, Audrey Tedja Widjaja, Pieter Vansteenwegen, Vincent F. Yu
Adaptive Large Neighborhood Search For Vehicle Routing Problem With Cross-Docking, Aldy Gunawan, Audrey Tedja Widjaja, Pieter Vansteenwegen, Vincent F. Yu
Research Collection School Of Computing and Information Systems
Cross-docking is considered as a method to manage and control the inventory flow, which is essential in the context of supply chain management. This paper studies the integration of the vehicle routing problem with cross-docking, namely VRPCD which has been extensively studied due to its ability to reducethe overall costs occurring in a supply chain network. Given a fleet of homogeneous vehicles for delivering a single type of product from suppliers to customers through a cross-dock facility, the objective of VRPCD is to determine the number of vehicles used and the corresponding vehicle routes, such that the vehicleoperational and transportation …
Scheduling Problem Of Unidirectional Material Handling System With Short-Cut, Juntao Li, Kun Xia, Kise Hiroshi
Scheduling Problem Of Unidirectional Material Handling System With Short-Cut, Juntao Li, Kun Xia, Kise Hiroshi
Journal of System Simulation
Abstract: Unidirectional circulation-type material handling system on a single loop with a shortcut is a typical and basic unit in a flexible manufacturing system or logistics system. It is widely used in semiconductor wafer fabrication system. Superposition efficiency of the basic unit often determines the one of the whole system. Different scheduling rules impact the interference between AGVs and then have an important effect on the efficiency of the whole system. To decrease the interference and improve performance of the system, a mathematical model of this system was made, analyzing this system by simulation and comparing the merits and …
A Matheuristic Algorithm For Solving The Vehicle Routing Problem With Cross-Docking, Aldy Gunawan, Audrey Tedja Widjaja, Pieter Vansteenwegen, Vincent F. Yu
A Matheuristic Algorithm For Solving The Vehicle Routing Problem With Cross-Docking, Aldy Gunawan, Audrey Tedja Widjaja, Pieter Vansteenwegen, Vincent F. Yu
Research Collection School Of Computing and Information Systems
This paper studies the integration of the vehicle routing problem with cross-docking, namely VRPCD. The aim is to find a set of routes to deliver single products from a set of suppliers to a set of customers through a cross-dock facility, such that the operational and transportation costs are minimized, without violating the vehicle capacity and time horizon constraints. A two-phase matheuristic approach that uses the routes of the local optima of an adaptive large neighborhood search (ALNS) as columns in a set-partitioning formulation of the VRPCD is designed. This matheuristic outperforms the state-of-the-art algorithms in solving a subset of …