Sharif Digital Repository

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... 

Train scheduling is one of the most complicated stages of railway planning. In this stage, the arrival and departure times of trains at stations are determined. In this thesis, we studied train scheduling on a two-way and single track railway in order to minimize the total travel times of trains subject to a set of operational constraints and prayer time related constraints that determines the optimal station for prayer. In this project, we tried to simulate the real constraints exist in IRAN railway network and the objective function considers customer’s and railway management’s satisfaction, simultaneously. First, a mathematical programming is proposed for this problem. After demonstrating... 

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... 

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.... 

Network coding as an efficient approach for performance improvement of communication networks has been introduced by Ahlswede et al. Despite simple forwarding schemes, in network coding scenarios, intermediate nodes forward the encoded version of their received packets. In wireless Networks, resource allocation includes routing, network coding, flow control, scheduling and power control.In this dissertation a joint scheduling, routing, flow control and Inter-session NC formulation based on a convex optimization problem is studied. Our formulation integrates the optimal scheduling, flow control and Inter-session network coding with a modified version of minimum delay routing. We propose a way... 

This study addresses the simultaneous berth and quay crane (QC) scheduling problem in a container terminal. The berths are considered as a continuous area and the vessels arrive dynamically. QCs are allowed to move to other vessels before completing the process on an assigned vessel.The objective function is determined based on the practical applications of the problem. It deals with minimization of sum of the completion time of vessels. In this research, a mathematical model has been developed for the research problem. According to NP-hardness of the research problem, two meta heuristic algorithms based on Tabu Search are proposed. To solve the problem, these methods have two layers with... 

In this thesis, a multi-stage project portfolio selection and scheduling problem in an uncertain environment is modeled, analyzed and solved. Moreover, we investigate the situations in which a project manager is confronted to a large number of projects to be selected and scheduled while the required resources of the projects are limited and renewable. The aim is to maximize objective function which is the net present value of the profit of the projects. To solve the mentioned problem, we introduce a multi-stage stochastic programming. For the reason that, in real problems, optimization problems that included all restraints are large scale and have computational complexity, these problems are... 

This research deals with the problem of scheduling independent preemptive jobs on identical parallel machines, to minimize the total completion time (makespan). The transportation of an interrupted job from a machine to another machine requires considering a constant transportation delay i.e., Pm|prmp(delay)| Cmax. This delay is called transportation delay. We propose a Mixed Integer Linear Programming formulation for the research problem in case of two machines i.e., P2|prmp(delay)| Cmax. Since the research problem is shown to be NP-hard, a particle swarm optimization (PSO) algorithm is applied to solve the problem approximately. Based on the frequency of using local search procedure, three... 

One of the main applications of revenue management is in healthcare industry. By combining these two concepts, subjects such as patient allocation and scheduling and no-show rates were developed in the literature. Up until now, allocation and scheduling were considered separately in the literature. Also, no-show rates were predicted using regression models and data mining tools and these predictions were rarely used in scheduling systems. In this thesis, we combined allocation based on patients’ insurance type with scheduling based on patients’ no-show rates. Also, patients’ no-show rates were predicted and these rates were used in the proposed scheduling model. Firstly, the integrated... 

Reliable forecasting is a fundamental element of successful project management. Construction managers regularly control and monitor their project in order to ensure that their project performance is under control and within the acceptable control limits. Conventionally, the earned value method (EVM) is used to monitor project cost performance. However, its application to schedule performance using schedule performance index (SPI) has been widely questioned both by practitioners and researchers particularly due to poor accuracy early in the project. This study presents a novel activity-based framework, namely Weibull Evaluation and Forecasting Method (WEFM), for stochastic evaluation and... 

Using the cross docking is a strategy that plays inventory coordinating role in the supply chain. At the cross docking, products of inbound trucks are unloaded, sorted, moved and loaded onto outbound trucks for delivery to different destinations. In this concept, coordination between inbound and outbound trucks considering a cross-dock system with multiple receiving and shipping dock doors. Moreover, due to justifiability of all trucks to carry multiple product types, product assignment from inbound trucks to outbound trucks is determined simultaneous to scheduling. As an exact solution approach a MIP model is presented and since the problem is shown to be NP-hard, it can only be used to... 

Train scheduling is a significant issue in the railway industry in recent years because it has an important role in railway infrastructure. In this paper, the timetabling problem of a multiple tracked railway network is discussed. More specifically, a general model with specific attention to “Tehran Metro” is presented here in which a set of operational and safety requirements are also considered. The model handles the trains overtaking in a station and innovatively considers the capacity of stations. An objective function is to minimize the total travel time. The problem is NP-hard so the real size problem cannot be solved in acceptable amount of time. In order to reduce the processing time... 

This study strives to minimize a two-criterion objective function of a flexible flow shop scheduling problem with receipt and delivery of jobs in groups and processing them individually. Every group of jobs has a release time, which means that all jobs are not available at the beginning of the planning horizon. Moreover, due to the special characteristics of every job in a group, only a subset of machines at each stage are eligible to process that job. This problem has many applications in production and service industries, such as restaurants and ceramic tile manufacturing companies. The objective function is determined based on the practical applications of the problem. It deals with... 

Finding a proper and fair schedule for sport competitions has been an important issue, especially these days which professional sports has became a large scale business and profitability of sport competitions depends on the quality of the schedule.
Hence in the last three decades sport scheduling has been considered by computer science and operation research scientists.
Professional soccer league consists of many teams which compete in one round or double round robin tournament every year. In round robin tournaments each team has two matches, one at their own place and the other one at the competitors place. The main issues of the sport scheduling are the round and the host of... 

Increasing demand for higher data rates and more reliable communications along with growing applications of multimedia networks in everyday life on one hand, and limited resources on the other, have given rise to researches investigating spectrum efficiency enhancement techniques, among which multiuser diversity has always been of considerable importance. This thesis is a study on utilization of multiuser diversity in wireless LANs via scheduling. Where throughput and Quality of Service (QoS) in communication networks are being investigated, it is mostly advantageous to describe the traffic behavior of resources by greedy or non-greedy models. So far, there are plenty of investigations on... 

In this thesis, we consider the problem of scheduling parallel batching machines with different machine capacity and jobs of arbitrary sizes and processing times. The machines have identical processing velocity. The jobs are processed in batches given that the total size of jobs in a batch cannot exceed the machine capacity. Once a batch starts processing, no interruption is allowed until all the jobs are completed. First we present a mixed integer programming model of the problem. We show the computational complexity of the problem, and then we propose two heuristics, LPT-BF and LPT-FF with regard to constraints of problem. Finally, we generate different scales of instances to test the... 

The applications that consist ofprecedence-constrained parallel taskshave used in business activities and scientific projects and the energy consumption of these application has become a major concern in datacenters. At the software level, energy-aware task scheduling algorithmsare an effective technique for energy reduction and optimizing performance in data centers. The related works in this areahave traditionally ignore the utilization value of physical machines (PMs) and while the main reason of the energy inefficiency in datacenters is low average utilization of the PMs.In this paper, we propose a new energy-aware scheduling (EASy) algorithm forprecedence-constrained parallel taskswith... 

Increasing complexity of embedded systems and the need for more computation powerhave directed designers toward using of multiprocessors. SRAM-based FPGAs are suitable platforms for implementation of multiprocessors due to thier low cost, fast time-to-market and re-configurability. FPGA-based multiprocessors are known as soft multiprocessors. The large area of SRAM-based FPGAs is occupied by configuration bits. Configuration bits are vulnerable to high energy particles that can lead to soft errors. In this regards, it is of decisive importance to protect soft multiprocessors against soft errors. This thesis proposes a fault-tolerant method for soft multiprocessors that can detect and... 

High reliability by fault tolerance mechanisms and low energy consumption are two essential requirements for the major category of hard real-time systems that are used in safety-critical applications. Therefore many of previous researches in the safety-critical applications have presented various solutions to achieve these properties. Time and hardware redundancy techniques have been used extensively to achieve fault tolerance in the design of the hard real-time¬¬ systems. To achieve a high level of reliability, the time redundancy techniques are dependent on slack time. Therefore in some cases using the hardware redundancyto achieve the fault tolerance is inevitable. But the redundancy... 

In this Thesis pricing has been used in Job-shop scheduling problem in detailed scheduling point of view. Also, in this study, due date is price-dependent variable in wich the manufacturer has the ability to choose one item from some pairs of prices and due dates for every jobs in order to maximize the total profit, i.e. revenue less scheduling cost. In this problem, total weighted tardiness has been choosen for scheduling cost. In this research, pairs of prices and due dates has been studied. According to the complexity of this problem, a Genetic algorithm has been proposed to solving the problem. As a managerial insight, it shown that joint optimization of pricing and scheduling decisions...