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    A Model to Schedule Hospital Nurses Considering Nurses Preferences

    , M.Sc. Thesis Sharif University of Technology Pourmohsen, Rokhsareh (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    The nurse scheduling problem is an inevitable issue in managing of hospital wards. Maintaining high quality of working in hospitals is too difficult in tense and high-pressure work environment. Manually solving the scheduling problem is time-consuming. It can pose problems to considering individual excellence, personnel requests and distributing shifts in a fair and desirable manner. These problems and the impossibility of considering all conditions together made the nurse scheduling as an important scheduling problem. In this research we propose a model to assign nurses to shifts considering regulations and hospital’s policies. Unlike nurse scheduling literature we consider nurses... 

    A Mathematical Model for Providing Home Care Services by Hospital During COVID-19 Pandemic

    , M.Sc. Thesis Sharif University of Technology Pourbaferani, Mohaddeseh (Author) ; Eshghi, Kourosh (Supervisor)
    Abstract
    In this study, providing home care services by hospitals in the epidemic situations such as COVID-19 is proposed for the first time. Moreover, a mathematical formulation is developed to provide simultaneous decision-making about serving patients without COVID-19, scheduling nurses in the non-COVID-19 wards of hospitals, and scheduling and routing for nurses to serve patients at home. This problem aims to develop essential compatibilities to keep people safe and help continue vital healthcare services during the COVID-19 and similar pandemics. Accordingly, nurses' preferences, the number of available hospital beds, the patient-to-nurse ratio, the Unavailability of some nurses due to COVID-19,... 

    A Rotation-based Branch-and-price for the Nurse Scheduling Problem

    , M.Sc. Thesis Sharif University of Technology Hovsepian, Angineh (Author) ; Mahdavi Amiri, Nezamoddin (Supervisor)
    Abstract
    Here, we explain an algorithm, recently introduced in the literature, for the personalized nurse scheduling problem. In this algorithm the authors focus on the deterministic counterpart of the specific problem that has been described in the second international nurse rostering competition. One specificity of this version is that most constraints are soft, meaning that they can be violated at the price of a penalty. The problem is modeled as an integer program (IP) and is solved using a branch-and-price procedure. In this model, each column of the IP corresponds to a rotation, i.e., a sequence of consecutive working days for a nurse. In contrast, classical models involve individual nurse... 

    Two-Stage Stochastic Programming Model for Nurse Scheduling with Consideration of Work-force Type

    , M.Sc. Thesis Sharif University of Technology Mirzavand Boroujeni, Niloufar (Author) ; Eshghi, Koroush (Supervisor) ; Sadri, Farzaneh (Co-Supervisor)
    Abstract
    The Nurse Scheduling Problem (NSP), is one of the most complicated problem in health care management systems. The problem is to determine a work schedule by considering some requirements such as governmental policies, staff and their managers satisfaction, etc. Nowadays, while the demand of treatment centers for nurses has increased especially in hospitals, the population of qualified nurses has decreased. In such a fuzzy situation, the managers of the treatment centers want a better nurse scheduling in order to increase the quality of giving services to their patients and consequently increase their income. In this thesis, a two-stage nurse scheduling problem with uncertainties in... 

    Developing a Multi-Skilled Project Scheduling Problem Model Considering Costs

    , M.Sc. Thesis Sharif University of Technology Makhan, Mohammad Reza (Author) ; Shadrokh, Shahram (Supervisor)
    Abstract
    This research intends to investigate the multi-skilled project scheduling problems (MSPSP) considering staffs’ dynamic efficiency. In doing so, a mixed-integer nonlinear programming (MINLP) model is proposed, considering the influence of personnel learning and forgetting on activities duration. The more the staff spends time on their various skills, the more learned and efficient they will be on that skill (according to personal learning curves) so that they can complete new tasks less costly and more quickly. Most project-based organizations want to maximize value by finishing the projects efficiently and developing their staff’s competence through projects. Inherently, any... 

    Nurse Scheduling of an Emergency Department in Order to Decreasing Patients Waiting Time Using Simulation and Genetic Algorithm

    , M.Sc. Thesis Sharif University of Technology Fazeli, Sajjad (Author) ; Mahlooji, Hashem (Supervisor)
    Abstract
    This work attempt to analyze the impact of changes in nurse scheduling on quality of services at emergency department of Emam Khomeini Hospital Complex. In nurse scheduling some constraints such as maximum working hours per week and unacceptable working sequences must be considered. A simulation model is developed to cover the complete flow for the patient through the emergency department. Emergency department of Emam Khomeini is simulated in order to obtain the patient average waiting time for each nurse roster. Then a genetic algorithm is integrated with the simulation model. In each iteration genetic algorithm produces many nurse rosters . For each roster the patient average waiting time... 

    Periodic Train Timetabling In Double-Way Railways By Considering The Praying Constraint

    , M.Sc. Thesis Sharif University of Technology Shekarchian, Sajjad (Author) ; Kianfar, Freydoon (Supervisor)
    Abstract
    Train timetabling is one of the most important problems in the railway scheduling field. It concerns with determining the trians’ arrival and departure times to/from each station so that some constraints are satisfied and some objectives are met. The objective in this thesis is to minimize the summation of dwell times of all trains. The timetables which are offered in this thesis are periodic. It means that each event repeats after a period time. The events are arrivals and departures of trains to/ from stations. In this timetable, the praying constraint is considered as wellso that after Azan time, the train has to dwell in the first station which has enough place for praying. So an integer... 

    Developing Mathematical Model and a Meta-Heuristic Algorithm for Nurse Scheduling Problem

    , M.Sc. Thesis Sharif University of Technology Jafari, Hamed (Author) ; Salmasi, Naser (Supervisor)
    Abstract
    Nurse scheduling problem has received a great amount of attention during recent years. In this problem number of needed nurses from different skill levels is given for each Location-shift during planning horizon, and the goal is to allocate each nurse to shifts, such that the demand of each location-shift is satisfied. Many researches have been done with the aim of minimizing the number of needed nurses to satisfy the demand of locationshifts or maximizing nurses preferences to work in desired shifts. In this research an integer programming model is proposed to minimize the number of needed nurses and maximize nurses preferences simultaneously. The proposed mathematical model is appropriate... 

    Fast aggregation scheduling in wireless sensor networks

    , Article IEEE Transactions on Wireless Communications ; Volume 14, Issue 6 , 2015 , Pages 3402-3414 ; 15361276 (ISSN) Yousefi, H ; Malekimajd, M ; Ashouri, M ; Movaghar, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    Data aggregation is a key, yet time-consuming functionality introduced to conserve energy in wireless sensor networks (WSNs). In this paper, to minimize time latency, we focus on aggregation scheduling problem and propose an efficient distributed algorithm that generates a collision-free schedule with the least number of time slots. In contrast to others, our approach named FAST mainly contributes to both tree construction, where the former studies employ Connected 2-hop Dominating Sets, and aggregation scheduling that was previously addressed through the Competitor Sets computation. We prove that the latency of FAST under the protocol interference model is upper-bounded by 12R+Δ-2, where R... 

    An efficient hybrid genetic algorithm to solve assembly line balancing problem with sequence-dependent setup times

    , Article Computers and Industrial Engineering ; Volume 62, Issue 4 , 2012 , Pages 936-945 ; 03608352 (ISSN) Yolmeh, A ; Kianfar, F ; Sharif University of Technology
    2012
    Abstract
    In this paper the setup assembly line balancing and scheduling problem (SUALBSP) is considered. Since this problem is NP-hard, a hybrid genetic algorithm (GA) is proposed to solve the problem. This problem involves assigning the tasks to the stations and scheduling them inside each station. A simple permutation is used to determine the sequence of tasks. To determine the assignment of tasks to stations, the algorithm is hybridized using a dynamic programming procedure. Using dynamic programming, at any time a chromosome can be converted to an optimal solution (subject to the chromosome sequence). Since population diversity is very important to prevent from being trapped in local optimum... 

    Sequence-dependent flow shop scheduling problem minimising the number of tardy jobs

    , Article International Journal of Production Research ; Volume 50, Issue 20 , 2012 , Pages 5843-5858 ; 00207543 (ISSN) Varmazyar, M ; Salmasi, N ; Sharif University of Technology
    2012
    Abstract
    Flow shop scheduling problems with sequence-dependent setup times and minimising the number of tardy jobs as the criterion (F m |prmu, S ijk |∑U j) are considered in this research. A mixed-integer linear programming model is developed for the research problem. Since the proposed research problem has been proven to be NP-hard, several meta-heuristic algorithms based on tabu search (TS) and the imperialist competitive algorithm (ICA) are proposed to heuristically solve the problem. In order to find the best meta-heuristic algorithm, random test problems, ranging in size from small, medium, to large, are generated and solved by the meta-heuristic algorithms. Then, a detailed statistical... 

    Minimizing the number of tardy jobs in flow shop sequence dependent setup times scheduling problem

    , Article Applied Mechanics and Materials ; Volume 110-116 , 2012 , Pages 4063-4069 ; 16609336 (ISSN) ; 9783037852620 (ISBN) Varmazyar, M ; Salmasi, N ; Sharif University of Technology
    2012
    Abstract
    This paper investigates permutation flow shop scheduling problems with sequencedependent setup times with minimizing the number of tardy jobs as criterion (F m|prmu, S ijk|σU j). Since the proposed research problem has been proven to be NP-hard, three different meta heuristic algorithms based on tabu search (TS) has been proposed to solve the problem. These three algorithms are different based on their tabu list characteristics. In order to evaluate the performance of the proposed TS algorithms, test problems in different ranges are generated to find the best algorithm. The comparison shows that the TS algorithm which its tabu list keeps track of the slots that the jobs are assigned has a... 

    A Hybrid PSO-SA algorithm for the traveling tournament problem

    , Article 2009 International Conference on Computers and Industrial Engineering, CIE 2009, 6 July 2009 through 9 July 2009, Troyes ; 2009 , Pages 512-518 ; 9781424441365 (ISBN) Tajbakhsh, A ; Eshghi, K ; Shamsi, A ; Sharif University of Technology
    Abstract
    Sports scheduling has become an important area of applied operationsresearch in recent years, since satisfying the fans and teams' requests andrevenues of a sports league and TV networks may be affected by the quality ofthe league schedule. While this type of scheduling problem can be solvedtheoretically by mathematical methods, it computationally leads to hardproblems. The Traveling Tournament Problem (TTP) is defined as minimizing totaltraveling distance for all teams in the league. In this study, a newmathematical model for the TTP with no-repeater constraint is presented. Inaddition, a very fast hybrid metaheuristic algorithm is proposed, which combinesParticle Swarm Optimization (PSO)... 

    A two-criteria objective function flexible flowshop scheduling problem with machine eligibility constraint

    , Article International Journal of Advanced Manufacturing Technology ; Volume 64, Issue 5-8 , April , 2013 , Pages 1001-1015 ; 02683768 (ISSN) Tadayon, B ; Salmasi, N ; Sharif University of Technology
    2013
    Abstract
    This research deals with a flexible flowshop scheduling problem with the arrival and delivery of jobs in groups and processing them individually. Each group of jobs has a specific release time. Due to the special characteristics of each job, only a specific group of machines in each stage are eligible to process that job. All jobs in a group should be delivered at the same time after processing. The objectives of the problem are the minimization of the sum of the completion time of groups on one hand and the minimization of sum of the differences between the completion time of jobs and the delivery time of the group containing that job (waiting period) on the other hand. The problem can be... 

    Branch and bound algorithms for resource constrained project scheduling problem subject to nonrenewable resources with prescheduled procurement

    , Article Mathematical Problems in Engineering ; Vol. 2014, issue , 2014 ; ISSN: 1024123X Shirzadeh Chaleshtarti, A ; Shadrokh, S ; Fathi, Y ; Sharif University of Technology
    Abstract
    A lot of projects in real life are subject to some kinds of nonrenewable resources that are not exactly similar to the type defined in the project scheduling literature. The difference stems from the fact that, in those projects, contrary to the common assumption in the project scheduling literature, nonrenewable resources are not available in full amount at the beginning of the project, but they are procured along the project horizon. In this paper, we study this different type of nonrenewable resources. To that end, we extend the resource constrained project scheduling problem (RCPSP) by this resource type (RCPSP-NR) and customize four basic branch and bound algorithms of RCPSP for it,... 

    A hybrid genetic and Lagrangian relaxation algorithm for resource-constrained project scheduling under nonrenewable resources

    , Article Applied Soft Computing Journal ; Volume 94 , 2020 Shirzadeh Chaleshtarti, A ; Shadrokh, S ; Khakifirooz, M ; Fathi, M ; Pardalos, P. M ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Scheduling under nonrenewable resources is one of the challenging issues in project scheduling problems. There are many cases where the projects are subject to some nonrenewable resources. In most of the literature, nonrenewable resources are assumed to be available in full amount at the beginning of the project. However, in practice, it is prevalent that these resources are procured along the project horizon. This paper studies the generalized resource-constrained project scheduling problem (RCPSP) where, in addition to renewable resources, nonrenewable resources are considered, such as budget or consuming materials by the project activities. As the problem is NP-hard, some sub-algorithm... 

    Statistical design of genetic algorithms for combinatorial optimization problems

    , Article Mathematical Problems in Engineering ; Volume 2011 , 2011 ; 1024123X (ISSN) Shahsavar, M ; Najafi, A. A ; Niaki, S. T. A ; Sharif University of Technology
    2011
    Abstract
    Many genetic algorithms (GA) have been applied to solve different NP-complete combinatorial optimization problems so far. The striking point of using GA refers to selecting a combination of appropriate patterns in crossover, mutation, and and so forth and fine tuning of some parameters such as crossover probability, mutation probability, and and so forth. One way to design a robust GA is to select an optimal pattern and then to search for its parameter values using a tuning procedure. This paper addresses a methodology to both optimal pattern selection and the tuning phases by taking advantage of design of experiments and response surface methodology. To show the performances of the proposed... 

    Three self-adaptive multi-objective evolutionary algorithms for a triple-objective project scheduling problem

    , Article Computers and Industrial Engineering ; Volume 87 , September , 2015 , Pages 4-15 ; 03608352 (ISSN) Shahsavar, A ; Najafi, A. A ; Niaki, S. T. A ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    Finding a Pareto-optimal frontier is widely favorable among researchers to model existing conflict objectives in an optimization problem. Project scheduling is a well-known problem in which investigating a combination of goals eventuate in a more real situation. Although there are many different types of objectives based on the situation on hand, three basic objectives are the most common in the literature of the project scheduling problem. These objectives are: (i) the minimization of the makespan, (ii) the minimization of the total cost associated with the resources, and (iii) the minimization of the variability in resources usage. In this paper, three genetic-based algorithms are proposed... 

    Project scheduling and equipment planning with random breakdowns

    , Article RAIRO - Operations Research ; Volume 51, Issue 4 , 2017 , Pages 1189-1209 ; 03990559 (ISSN) Shafikhani, A ; Najafi, A. A ; Akhavan Niaki, S. T ; Sharif University of Technology
    Abstract
    Most of the research works conducted on Project Scheduling Problem (PSP) especially Resource Constrain Project Scheduling Problem (RCPSP) either ignore equipment planning or schedule the activities first, and then plan for the required equipment. Moreover, little works that consider simultaneous PSP and Equipment Planning (EP) are based on the assumption that the equipment is continuously available. However, in reality, equipment is subject to either random breakdowns or deterministic maintenance programs that make it not being available all the time. In this paper, the PSP and EP problems are simultaneously considered in closer to reality situations in which the equipment is not always... 

    Job shop scheduling with the option of jobs outsourcing

    , Article International Journal of Production Research ; Volume 57, Issue 10 , 2019 , Pages 3255-3272 ; 00207543 (ISSN) Safarzadeh, H ; Kianfar, F ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Abstract
    Incorporating outsourcing in scheduling is addressed by several researchers recently. However, this scope is not investigated thoroughly, particularly in the job shop environment. In this paper, a new job shop scheduling problem is studied with the option of jobs outsourcing. The problem objective is to minimise a weighted sum of makespan and total outsourcing cost. With the aim of solving this problem optimally, two solution approaches of combinatorial optimisation problems, i.e. mathematical programming and constraint programming are examined. Furthermore, two problem relaxation approaches are developed to obtain strong lower bounds for some large scale problems for which the optimality is...