scholarly journals Dynamic Scheduling Based on Predicted Inventory Variation Rate for Public Bicycle System

2019 ◽  
Vol 11 (7) ◽  
pp. 1885
Author(s):  
Liang Gao ◽  
Wei Xu ◽  
Yifeng Duan
Keyword(s):  
Dynamic Scheduling ◽  
Process Condition ◽  
Mixed Integer ◽  
Scheduling Problem ◽  
Rolling Horizon ◽  
The Public ◽  
Mip Model ◽  
Variation Rate ◽  
Stationary Markov Process

To improve efficiency and reduce the total scheduling cost of the public bicycle system (PBS), dynamic scheduling based on the predicted inventory variation rate (DS-PIVR) is proposed. Regarding a station in the PBS as an inventory system, its inventory variation rate during the scheduling period and its inventory rate at the end of the scheduling period were predicted based on the stationary Markov process condition. A mixed integer programming (MIP) model, whose objective is to minimize the total scheduling distance, was established to describe the dynamic scheduling problem (DSP). Results from Boston and Washington D.C. PBSs show that, when compared to the dynamic scheduling based on the rolling horizon (DS-RH), the DS-PIVR method could at most shorten the routing distance by 62.25% (for Boston) and 74.7% (for Washington D.C.) among all scheduling areas, and could at most shorten the total routing distance for the whole PBS by 21.06% (for Boston) and 17.26% (for Washington D.C.). Moreover, the DS-PIVR method makes the repositioning vehicle journey only once and keeps the inventory rate of each station in balance during the scheduling period. Furthermore, the DS-PIVR method provides a promising reference to improve the operation efficiency by reducing the scheduling cost and the quality of service by satisfying the users’ demand in time during the rush hours for the PBS operators.

scholarly journals Balanced Scheduling of School Bus Trips using a Perfect Matching Heuristic

2018 ◽  
Vol 2672 (48) ◽  
pp. 1-11 ◽  
Author(s):  
Ali Shafahi ◽  
Sanaz Aliari ◽  
Ali Haghani
Keyword(s):  
Heuristic Algorithm ◽  
School Setting ◽  
Mixed Integer ◽  
Scheduling Problem ◽  
School Bus ◽  
Heuristic Solution ◽  
Mip Model ◽  
Bus Scheduling ◽  
Minimum Number ◽  
The Cost

In the school bus scheduling problem, the main contributing factor to the cost is the number of buses needed for the operations. However, when subcontracting the pupils’ transportation, unbalanced tours can increase the costs significantly as the lengths of some tours can exceed the daily fixed driving goal and will result in over-hour charges. This paper proposes a mixed integer programming (MIP) model and a matching-based heuristic algorithm to solve the “balanced” school bus scheduling problem with fixed start times in a multi-school setting. The heuristic solution always has the minimum number of buses as it starts with a minimal number of tours and does not alter the number of tours during its balancing stage. The effectiveness of the heuristic is tested by comparing its solutions with results from solving the MIP using commercial solvers whenever solvers could find a good solution. To illustrate the performance of the MIP and the heuristic, 11 problems were examined with different numbers of trips which are all based on two real-world problems: a California case study with 54 trips and the Howard County Public School System with 994 trips. Our numerical results indicate the proposed heuristic algorithm can find reasonable solutions in a significantly shorter time. The balanced solutions of our algorithm can save up to 16% of school bus operation costs compared with the best solution found by solvers from optimizing the MIP model after 40 hours. The balancing stage of the heuristic decreases the standard deviation of the tour durations by up to 47%.

Tandem Lift Quay Cranes and Yard Trucks Scheduling Problem at Container Terminals

2014 ◽  
Vol 505-506 ◽  
pp. 927-930 ◽  
Author(s):  
Li Hua Chen ◽  
Jin Xin Cao ◽  
Qing Yu Zhao
Keyword(s):  
Integer Programming ◽  
Mixed Integer Programming ◽  
Container Terminals ◽  
Mixed Integer ◽  
Scheduling Problem ◽  
Truck Scheduling ◽  
Mip Model ◽  
Quay Cranes ◽  
Local Sequence ◽  
Cut Method

The reasonable dispatching and scheduling of the Tandem Quay Cranes and trucks is the foundation to improve the efficiency of the container terminals. Under the base of single lift quay cranes research, a research on Tandem Lift Quay Cranes and Yard Trucks scheduling is carried on in this paper. A mixed integer programming (MIP) model can be built to solve an integrated tandem lift quay crane and yard truck scheduling problem (i-TLQCYT). A Local Sequence-cut Method is applied to solve the model. Then the shortest time to complete the unloading operations can be got.

scholarly journals MILP Model and a Rolling Horizon Algorithm for Crane Scheduling in a Hybrid Storage Container Terminal

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Kai Yu ◽  
Jingcheng Yang
Keyword(s):  
Container Terminal ◽  
Computation Time ◽  
Mixed Integer ◽  
Scheduling Problem ◽  
Rolling Horizon ◽  
Crane Scheduling ◽  
Storage Container ◽  
Hybrid Storage ◽  
Yard Crane Scheduling ◽  
Milp Model

This paper investigates the yard crane scheduling problem of a hybrid storage container terminal whose import containers and export containers are stored together in each block. The combination of containers improves the space utilization of a container terminal while it also creates new challenges for the yard crane scheduling. To formulate this problem, we propose a mixed integer linear programming (MILP) model, which jointly optimizes trucks’ waiting costs and penalty costs caused by exceeding waiting time thresholds. Considering the NP-completeness of this scheduling problem, we develop an efficient rolling horizon algorithm based on some heuristics to reduce the computation time. Finally, computational studies are carried out to evaluate the performance of our method and the solutions obtained by CPLEX solver are used for benchmarking purposes.

scholarly journals Efficient algorithms to minimize Makespan of the unrelated parallel Batch-processing machines scheduling problem with unequal job ready times

2021 ◽  
Author(s):  
yaser zarouk ◽  
javad rezaeian ◽  
iraj mahdavi ◽  
Masoud Yaghini
Keyword(s):  
Processing Speed ◽  
Mixed Integer Linear Programming ◽  
Processing Time ◽  
Original Problem ◽  
Batch Processing ◽  
Mixed Integer ◽  
Scheduling Problem ◽  
Batch Processing Machines ◽  
Ready Time

This paper considers the minimization of makespan in the unrelated parallel batch processing machines scheduling problem with considering non-identical job size and dynamic job ready time. The considered unrelated machines have different capacity and different processing speed. Each machine processes a number of the jobs as a batch at the same time so that the machine’s capacity is not exceeded. The batch processing time and the batch ready time are equal to the largest processing time and the largest ready time of jobs in the same batch, respectively. In this paper, a Mixed Integer Linear Programming (MILP) model, two categories of the heuristic procedures (six heuristics) and a meta-heuristic algorithm are proposed to solve the problem. A lower bound is also presented by relaxing of the original problem to evaluate the quality of the proposed algorithms. The computational experiments show the performance of the proposed algorithms under the considered measures.

scholarly journals A Dynamic Scheduling Method for Carrier Aircraft Support Operation under Uncertain Conditions Based on Rolling Horizon Strategy

2018 ◽  
Vol 8 (9) ◽  
pp. 1546 ◽  
Author(s):  
Peilong Yuan ◽  
Wei Han ◽  
Xichao Su ◽  
Jie Liu ◽  
Jingyu Song
Keyword(s):  
Renewable Resources ◽  
Large Scale ◽  
Dynamic Scheduling ◽  
Dynamic Environment ◽  
Optimization Method ◽  
Scheduling Problem ◽  
Rolling Horizon ◽  
Scheduling Strategy ◽  
Mutation Strategy ◽  
Event Driven

The efficient scheduling of carrier aircraft support operations in the flight deck is important for battle performances. The supporting operations and maintenance processes involve multiple support resources, complex scheduling process, and multiple constraints; the efficient coordination of these processes can be considered a multi-resource constrained multi-project scheduling problem (MRCMPSP), which is a complex non-deterministic polynomial-time hard (NP-hard) problem. The renewable resources include the operational crews, resource stations, and operational spaces, and the non-renewable resources include oil, gas, weapons, and electric power. An integer programming mathematical model is established to solve this problem. A periodic and event-driven rolling horizon (RH) scheduling strategy inspired by the RH optimization method from predictive control technology is presented for the dynamic scheduling environment. The periodic horizon scheduling strategy can track the changes of the carrier aircraft supporting system, and the improved event-driven mechanism can avoid unnecessary scheduling with effective resource allocation under uncertain conditions. The dual population genetic algorithm (DPGA) is designed to solve the large-scale scheduling problem. The activity list encoding method is proposed, and a new adaptive crossover and mutation strategy is designed to improve the global exploration ability. The double schedule for leftward and rightward populations is integrated into the genetic process of alternating iterations to improve the convergence speed and decrease the computation amount. The computational results show that our approach is effective at solving the scheduling problem in the dynamic environment, as well as making better decisions regarding disruption on a real-time basis.

Comparing Mathematical and Heuristic Rules for Solving Single Machine Scheduling Problem with Release and due Date Constraints

2014 ◽  
Vol 635-637 ◽  
pp. 1707-1710
Author(s):  
Yong Zhan ◽  
Hai Tao Zhu ◽  
Yu Guang Zhong
Keyword(s):  
Single Machine ◽  
Numerical Experiments ◽  
Machine Scheduling ◽  
Single Machine Scheduling ◽  
Mixed Integer ◽  
Scheduling Problem ◽  
Heuristic Rules ◽  
Due Date ◽  
Mip Model ◽  
Accuracy Of Results

The purpose of this paper is to compare a mixed integer programming (MIP) model, and heuristic rules based on their practical efficiency and the accuracy of results to tackle the minimum lateness single machine scheduling problem with release and due date constraints. Extensive numerical experiments are carried out on randomly generated testing instances in order to evaluate the performance of the MIP model and heuristic rules.

scholarly journals A Dynamic Scheduling Method of Earth-Observing Satellites by Employing Rolling Horizon Strategy

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Qiu Dishan ◽  
He Chuan ◽  
Liu Jin ◽  
Ma Manhao
Keyword(s):  
Integer Programming ◽  
Dynamic Scheduling ◽  
Heuristic Algorithms ◽  
Programming Model ◽  
Scheduling Algorithms ◽  
Scheduling Problem ◽  
Rolling Horizon ◽  
Static Scheduling ◽  
Event Triggering ◽  
Scheduling Method

Focused on the dynamic scheduling problem for earth-observing satellites (EOS), an integer programming model is constructed after analyzing the main constraints. The rolling horizon (RH) strategy is proposed according to the independent arriving time and deadline of the imaging tasks. This strategy is designed with a mixed triggering mode composed of periodical triggering and event triggering, and the scheduling horizon is decomposed into a series of static scheduling intervals. By optimizing the scheduling schemes in each interval, the dynamic scheduling of EOS is realized. We also propose three dynamic scheduling algorithms by the combination of the RH strategy and various heuristic algorithms. Finally, the scheduling results of different algorithms are compared and the presented methods in this paper are demonstrated to be efficient by extensive experiments.

Assessments of User Comments With “Alternative Views” as a Function of Media Trust

2020 ◽  
pp. 1-12
Author(s):  
Marlene Kunst
Keyword(s):  
Online Discussions ◽  
Future Research ◽  
Political Issues ◽  
Argument Quality ◽  
The Public ◽  
Mainstream Media ◽  
User Comments ◽  
Media Trust ◽  
Heuristic Information Processing

Abstract. Comments sections under news articles have become popular spaces for audience members to oppose the mainstream media’s perspective on political issues by expressing alternative views. This kind of challenge to mainstream discourses is a necessary element of proper deliberation. However, due to heuristic information processing and the public concern about disinformation online, readers of comments sections may be inherently skeptical about user comments that counter the views of mainstream media. Consequently, commenters with alternative views may participate in discussions from a position of disadvantage because their contributions are scrutinized particularly critically. Nevertheless, this effect has hitherto not been empirically established. To address this gap, a multifactorial, between-subjects experimental study ( N = 166) was conducted that investigated how participants assess the credibility and argument quality of media-dissonant user comments relative to media-congruent user comments. The findings revealed that media-dissonant user comments are, indeed, disadvantaged in online discussions, as they are assessed as less credible and more poorly argued than media-congruent user comments. Moreover, the findings showed that the higher the participants’ level of media trust, the worse the assessment of media-dissonant user comments relative to media-congruent user comments. Normative implications and avenues for future research are discussed.

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