Scheduling
Saeideh Naderi; Mohsen Vaez-Ghasemi; farzad movahedi sobhani
Abstract
The Resource-Constrained Project Scheduling Problem (RCPSP) is a general one in scheduling which possesses various applications in production, production scheduling, project managing and other criteria. This issue has been studied since 1960 and is very complicated. In this study, the common presuppositions ...
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The Resource-Constrained Project Scheduling Problem (RCPSP) is a general one in scheduling which possesses various applications in production, production scheduling, project managing and other criteria. This issue has been studied since 1960 and is very complicated. In this study, the common presuppositions and limitations regarding such problems will be investigated in addition to their reliability in modelization in order to investigate the possibility of availability of renewable resources using a new attitude. The objective of modelization of RCPSP is quantification of total costs and minimization of delays in projects. Therefore, in order to mathematically modelize RCPSP, non-linear complex integer math programming which transforms into a linear programming model using the features of exponential functions is used. In order to solve the final linear math problem, some experimental examples will be designed in different dimensions, so that the performance and efficiency of the designed model are studied. For solving problems with low dimensions , the Epsilon Constraint multi-objective optimization method is used in an exact optimization software like Lingo. In order to find out the solutions of the ones whose dimensions are high, which exact methods can not solve,the meta-heuristic algorithm called NSGA-II which is a strong one to optimize multi objective problems is used. The results of using these algorithms and the statistical analysis which shows their reliability as 95 percent , indicates that the performance is suitable for genetic algorithms. Therefore this meta-heuristic algorithm has more efficiency and more apposite performance for the recommended model compared with the software of exact optimization. Using the designed math model ,this study can result in decreasing the times of delay in projects and the costs in the scheduling problem and also increasing the reliability when activities are multi-mode.
Scheduling
Esmaeil Mehdizadeh; Fatemeh Soleimaninia
Abstract
The Flexible Job shop Scheduling Problem (FJSP), as a Production Scheduling Problem (PSP), is generally an extension of the Job shop Scheduling Problem (JSP). In this paper, the FJSP with reverse flow consisting of two flows of jobs (direct and reverse) at each stage is studied; the first flow initiates ...
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The Flexible Job shop Scheduling Problem (FJSP), as a Production Scheduling Problem (PSP), is generally an extension of the Job shop Scheduling Problem (JSP). In this paper, the FJSP with reverse flow consisting of two flows of jobs (direct and reverse) at each stage is studied; the first flow initiates in Stage 1 and goes to Stage C (the last stage), and the second flow starts with Stage c and ends up in Stage 1. The aim is to minimize the makespan of the jobs (the maximum completion time). A Mixed Integer Programming (MIP) is presented to model the problem and the Branch and Bound (B&B) method is used to solve the problem. A numerical small-size problem is presented to demonstrate the applicability, for which the Lingo16 software is employed for a solution. Due to the NP-hardness of the problem, a meta-heuristic, namely the Vibration Damping Optimization (VDO) algorithm with tuned parameters using the Taguchi method, is utilized to solve large-scale problems. To validate the results obtained using the proposed solution algorithm in terms of the solution quality and the required computational time, they are compared with those obtained by the Lingo 16 software for small-size problems. Finally, the performance of the proposed algorithm is compared with a Genetic Algorithm (GA) by solving some randomly generated larger-size test problems, based on which the results are analyzed statistically. Computational results confirm the efficiency and effectiveness of the proposed algorithm and show that the VDO algorithm performs well.
Scheduling
N. MD. Sarfaraj; Md. L. R. Lingkon; N. Zahan
Abstract
The continuous growth of the population causes an increased demand for our healthcare services. Insufficient hospitals face challenges to serve the patient within a preferable duration. Long lines in front of counters increase the processing time of a patient. From the entry to the completion, plenty ...
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The continuous growth of the population causes an increased demand for our healthcare services. Insufficient hospitals face challenges to serve the patient within a preferable duration. Long lines in front of counters increase the processing time of a patient. From the entry to the completion, plenty of time waste just for unscheduled hospital management system. Job shop scheduling is an optimization process in which jobs are assigned with maintain a particular sequence. In this paper, we proposed flexible job shop scheduling to solve this type of problem by considering patients as job and test counter as machine for the optimization of the processing time and increase the efficiency of a hospital or a clinic. Genetic Algorithm was used to analyze the processing time for multiple counter of a hospital for a stable and effective scheduling. The results showed that an optimized makespan was generated and patients could fulfill their needs much quickly after applying flexible job shop scheduling.
Scheduling
M. Hamid; R. Tavakkoli-Moghaddam; B. Vahedi-Nouri; H. Arbabi
Abstract
Operating rooms (ORs) are among the most influential departments of a hospital that a major portion of its expenditures and revenues originate from it. Due to the limited resources and the presence of different stockholders, effective management, and the optimal planning of this department are challenging. ...
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Operating rooms (ORs) are among the most influential departments of a hospital that a major portion of its expenditures and revenues originate from it. Due to the limited resources and the presence of different stockholders, effective management, and the optimal planning of this department are challenging. This paper develops a mathematical model to address the integrated problem of the operating room and surgical member scheduling with the objective of makespan minimization. In the proposed model, several aspects, including the availability and necessity of surgical members and equipment, and lunch break consideration, are incorporated. Finally, a case study related to an OR department in a general hospital is provided to assess the applicability and performance of the proposed model.
Scheduling
T. Chawasemerwa; I. W. Taifa; D. Hartmann
Abstract
Doctor scheduling is a complex, costly and time-consuming exercise. This study develops a constraint satisfaction and penalty minimisation scheduling model for meeting ‘hard constraints’ and minimises the cost of violating ‘soft constraints’, i.e. the user inputs, the total number ...
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Doctor scheduling is a complex, costly and time-consuming exercise. This study develops a constraint satisfaction and penalty minimisation scheduling model for meeting ‘hard constraints’ and minimises the cost of violating ‘soft constraints’, i.e. the user inputs, the total number of doctors to be scheduled, the maximum penalty to be met, and the minimum number of doctors to be assigned per shift. The algorithm creates a schedule which checks against all the constraints. The total schedule penalty associated with the constraint violations should be less than or equal to the user input penalty. If this condition is met, the schedule gets produced as the final and near-optimal solution. The model is managed to create a near optimal schedule with the minimal rule violations. However, it is challenging to provide a schedule with no rule violations. Such a situation is shown by the amount of computational time required to create a zero-penalty schedule, hours or even days needed to create a zero-penalty schedule. The system creates a schedule for a short period (weekly schedule) to promote flexibility; however, such a system does not promote fairness. Fairness is achieved through a cyclic schedule with rotations equal to the total number of doctors being scheduled. The system is managed to create a streamlined and flexible working environment and helped to improve the quality of healthcare. An optimization protocol can be incorporated into the system to reduce the search space and get the best optimal schedule since it is possible to get many schedules under the same user-defined parameters.
Scheduling
B. Naderi
Abstract
This paper considers the problem of university course timetabling. In this problem, there are a set of courses, lecturers and classrooms. The objective is to assign schedule courses so as to maximize the total preference of lecturer-course, lecturer-day and course-day. The paper first formulates the ...
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This paper considers the problem of university course timetabling. In this problem, there are a set of courses, lecturers and classrooms. The objective is to assign schedule courses so as to maximize the total preference of lecturer-course, lecturer-day and course-day. The paper first formulates the problem in form of linear integer programming model. Using the model and commercial software, the small sized instances are optimally solved. Then, the paper proposes three different algorithms based on imperialist competitive algorithm, simulated annealing and variable neighborhood search. The algorithms employ several novel procedures such as encoding scheme, move operator, crossing operators. The algorithms are tuned and evaluated with optimal solutions found by the model. Then, they are evaluated by comparing their performance. The results show that imperialist competitive algorithm outperforms the other algorithms.