Sharif Digital Repository

Sports scheduling with its interesting theory and application has been the subject of many research recently. Different problems arise from different league structures with different objectives. Inspired by the structure of soccer leagues in Britain and Netherlands, we study structures in which a different permutation of first half-season rounds is played during second half-season. Some leagues like Premier league in addition to this structure have a special property in which two teams may do not play against each other in the first half-season and play twice in the second half-season. Therefore, we study both structures separately. We present a mathematical model to cover both structures.... 

With the increasing development of Internet of Things (IoT) devices, issues such as establishing effective communication, optimizing energy consumption, ensuring reliability and improving the quality of services provided by these devices become more and more complex and critical challenges. With the introduction of fog computing model by Cisco in 2012, some of these challenges were successfully managed. Fog computing is a distributed computing paradigm that acts as a middle layer between cloud data centers and IoT-based devices/sensors. By distributing computing resources closer to edge devices, fog computing enables real-time data processing and analysis. However, one of the key aspects in... 

This research considers coordination of pricing and scheduling decisions in a make-to-order environment. We consider a two machine flowshop environment. The objective is to maximize the total net profit, i.e. revenue minus scheduling cost resulting from pricing and scheduling decisions. Prices of orders are set by the manufacturer and demand is a non-increasing function of price. Two mixed integer linear programming models have been developed for the research problem. As the problem is shown to be NP-Hard, a Metaheuristic algorithm is developed which is combination of two tabu search sub algorithms, one for pricing and the other for scheduling. And to evaluate performance, results from... 

This study focuses on two-machine flow shop problem where processing times are uncertain and the objective function is makespan. All information available about the processing time is an upper and lower bound and also expected value. The min-max and min-max regret version of the problem are adopted. In this study, in order to control the degree of conservatism of the solution, we suppose in each scenario the number of processing times on each machine that can deviate from its expected value is controllable. By considering the duality theorem, we present a mixed-integer programming model for the min-max problem. For each of two problems, we present an algorithm for finding objective value. We... 

A workflow management system is a software system which manages and coordinates the operational tasks of an organization. Typically, the def­ inition of a workflow involves human and computer resources and tools on various geographic locations, and thus the concerns of distributed systems are one of the main challenges in this domain. Following this,allocating various resources to different tasks of a workflow and schedul­ ing them in a manner which satisfies some predefined constraints is one of the new and fundamental challenges in this field.The main goal of this research is to design an agent-oriented workflow system which utilizes a novel method for resource allocation and schedul­ ing... 

Embedded systems usually need to have a Real-time function so that the time constraint has been one of the most essential attributes of these systems. In the design phase of these systems a scheduler must be presented by the designer so that the observance of system deadlines can be guaranteed( Hard Real-time Systems). Safety-critical applications not only must guarantee system deadlines despite the hard timing constraints in the presence of error, but also must operate correctly and tolerate the error. In some of these applications reducing power consumption is one of the most important objectives because of limited supply energy. The purpose of this project is to firstly study the methods... 

Due to increasing competition, Flexible Manufacturing System (FMS) take more attention in the new world. This flexibility is generally considered to fall into two categories, which both contain numerous subcategories. The first category, machine flexibility, covers the system's ability to be changed to produce new product types, and ability to change the order of operations executed on a part. The second category is called routing flexibility. Due to high variation in parts and low production volume, setup times are important. In this research, Flexible Jobshop Scheduling Problem with Sequence Dependent Setup Time (SDST-FJSP), as an extension of classical Jobshop scheduling problem (JSP), is... 

In this research sequence-dependent flowshop and flexible flowshop group scheduling problems are investigated. Several upper and lower bounding methods are proposed for the research problems. Permutation flowshop sequence-dependent group scheduling problem with minimization of total completion time is considered. Since the problem is shown to be strongly NP-hard, a Memetic algorithm (MA) is proposed. A lower bounding method base on the Branch-and-Price algrithm is also proposed. A statistical comparison shows that both the proposed MA and the proposed lower bounding method have better performance than the other methods from the literature with an average 5.96% percentage gap. Flexible... 

In the research, the order acceptance and scheduling problem is integrated with pricing in order to maximize the net profit. Two mixed linear integer programming models have been proposed for the problem. A two level tabu search algorithm is proposed to solve the model. The suitable structure is determined for the algorithm based on numerical experiments. Based on experimental design results, the hybrid of random initial solutions and swap move in neighborhoods determination is the best structure for the algorithm. Numerical analysis shows the reasonable performance of proposed algorithm  

Computational grids enabling resource sharing and coordination are now one of the common and acceptable technologies used for solving computational intensive applications rising in scientific and industrial problems. Nevertheless, due to the heterogeneity, dynamicity and autonomy of the grid resources, task scheduling within these systems has become a challenging research area. Applying the market model to the grids is a good approach which can easily take the dynamic characteristics of the grid resources into account and simplify the scheduling problem considering user-centric factors.In this thesis a two level market-based model for task scheduling problem in grid environment is presented.... 

With the proliferation of data centers, their ever-growing energy consumption has gained lots of attention from both academy and industry . Two primary parts that use majority of energy in data centers are IT equipment and cooling system or Computing Room Air Conditioning (CRAC) unit. Energy consumption of cooling system strongly relies on thermal performance of data center. Therefore, applying thermal management techniques for decreasing energy consumption of CRAC is a common practice. Moreover, the energy consumption of IT equipment affects the energy consumption of CRAC directly. Demand for more computing resources in data centers and their physical limits has, motivated the use of FPGAs ... 

Due to the undeniable importance and applicability of both "batch processing" and "parallel machines" in service and industry, this survey strives to solve a real-world problem in which some identical parallel machine, capable of processing jobs in batches, are available. In batch processing the process of jobs starts and ends simultaneously. In real world the processing time of the batch is a function of some characteristics of the jobs in the batch. in this survey, for simplicity (as calculating the mentioned function is so difficult), we assume that the processing time of a batch equals the sum of the processing time of the jobs in the batch. we also have assumed that the capacity of a... 

The traditional point of view on the scheduling of the healthcare systems, which is in common with the scheduling of other service and manufacturing systems, has contributed to inattention to patients’ psychological status and has given rise to many negative effects not only on them, but also on hospitals. However, this perspective has not been modified yet with respect to the features of healthcare systems, in which patients, rather that machines, are the main entities of the system. In this study, to address this draw back, a new concept, psyche-based optimization, as well as a new scheduling problem, anxiety-based scheduling of operating rooms, as the advent of this concept, have been... 

Multimedia applications which exploit the network resources are best provided in broadband networks. Additionally, broadband wireless access systems enable broadband access in places where the wired solutions are not applicable. The IEEE 802.16 standard is designed to provide broadband wireless access and addresses the PHY and MAC layers of wireless metropolitan area networks. This standard has been designed to support quality of service for different applications, and due to their various requirements has considered four classes of service for connections. However, quality of service support mechanisms (such as admission control and packet scheduling), are out of the scope of the standard.... 

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... 

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,... 

The project scheduling problem is one of the classic problems in project management that includes a range of optimization problems. One of the limitations we face in project scheduling problem is the resource constraint limitation. In many studies in the literature review, problems are based on the false assumption that a resource can be transferred between activities of a project or different projects without spending time and cost. The resource availability method in many fundamental researches in the context of resource constrained project scheduling problem (RCPSP) is considered as resource investment problems (RIP); while in many real world projects resources are rented for projects and... 

Project scheduling problems can be divided into different categories which one of the most important of them is resource investment problem. In this problem we are faced with a time limit for completion but resources are available unlimitedly and can be allocated to the project by specific cost. One of the most important constraints in real problems is the times that resources are available. In this research, resource investment problem considering calendar for resources has been investigated. Since resource investment problem is NP-Hard, after a brief overview of the different solutions, we used genetic algorithm to solve this problem. For this purpose, after determining chromosome... 

This thesis has developed a novel platform for digital dentistry which facilitates the interoperability among different digital components and improves digital workflow in a collaborative environment. The platform is inspired by the cloud manufacturing paradigm for enabling the interoperability and collaboration management and also applies the DICOM standard to improve the integration for the coordination among the different stakeholders for better sharing of their resources while they are geographically distributed. The paper has proposed the application of the PACS concept to include design, implant planning, process planning and production workstations. The paper has conducted a... 

Shipment of hazardous materials has got an important role in the world of today. Nowadays, sustainable development has got serious attention, and human health and environment are one of the sustainable development bases. The risk of hazardous materials for human health and environment, and also importance of this kind of materials in the industrial economy, make necessity of programming for shipment of hazardous materials more serious. This thesis, presents an optimiziation model for routing and scheduling for shipment of hazardous materials. This model is a multi criteria time varing mixed integer programming (MIP). The presented model, finds the optimal routs and scheduling of movement...