Sharif Digital Repository

As technology shrinks, the static power consumption is getting worse. Moreover, considering high usage of General-Purpose Graphics Processing Units (GPGPU), reducing the static power of GPGPUs is becoming an important issue. Execution units in GPGPUs are one of the most power hungry units that play an essential role in total power consumption of GPGPUs. On the other hand power gating is a promising method to reduce static power consumption. In this project, we propose a novel method to implement power-gating method for execution units with the negligible performance and power overheads. We utilize out of order execution in intra warp to keep the power-gated resources in off state more than... 

As an extension of known project scheduling problems which consider only time-independent costs, this problem includes both time- independent procurement costs and time-dependent renting costs for the resources. Consequently, in addition to projects where all resources are bought, we can deal with projects where resources are rented.
A resource Renting problem is a project-scheduling problem in which the availability levels of the rented resources are considered decision variables and the goal is to find a schedule and resource renting such that some objective function optimizes. In this thesis, we consider a resource renting problem in which the goal is to maximize the net present... 

The Emergency Department is one of the most important departments in a hospital, which is continuously active and plays a crucial role in saving patients' lives. For this reason, using research methods in operations and optimization can greatly help improve the performance of the Emergency Department. In this thesis, the emergency scheduling problem is examined with the objective function of minimizing the total weighted sum of job completion times, considering the random nature of service times. Since the objective function of the problem is to minimize the total job completion time, the job completion time is obtained as the sum of several random variables. Considering the additivity... 

The Operating Room (OR) is one of the most expensive resources of any hospital. Surgical costs typically account for approximately 40% of the total hospital resource costs, while surgeries typically generate around 67% of hospital revenues. Therefore, it is important to control the surgery costs while maintaining a high quality of care. In this study, all the decisions related to the Operating Theatre are being hierarchically considered in strategic, tactical and operational levels. The Operating Theatre consists of operation rooms, a recovery unit, an intensive care unit (ICU), a critical care unit (CCU), and ward units. In this model there exist many uncertainties, which the robust... 

In this research a no-wait flowshop sequence dependent setup time scheduling problem with weighted earliness-tardiness penalties as the criterion (F_m |nwt,S_ijk |∑▒〖w_j^' E_j+w_j^" T_j 〗) is investigated. It is assumed that n jobs are assigned to a flowshop with m machines. The jobs are not allowed to wait between two successive machines according to no-wait requirement. Moreover each machine needs a setup time before processing a new job. The value of this setup time is dependent on the previous processed job on that machine.
A mixed integer linear programming model is proposed to solve the problem. As the problem is shown to be strongly NP-hard, a particle swarm optimization (PSO)... 

Emerging technologies enable a set of distributed resources across a network tobe linked together and used in a coordinated fashion to solve a particular parallel applicationat the same time. Such applications are often abstracted as directed acyclicgraphs (DAGs), in which vertices represent application tasks and edges represent datadependencies between tasks.The problem of scheduling in a distributed environment is that ofdeciding where to place tasks, and when to start execution of the tasks. Effective scheduling mechanisms for DAG applicationsare essential to exploit the potential of computational resources. Fault tolerance is an important requirement in distributed computing systems when... 

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... 

In this thesis departure programming are studied in general state and takeoff programming studied in special state. Departure programming consists of several parts that decisions for each part may influence in the other parts. Because of unforeseen delays this problem is a dynamic problem. Holding area is a part that overtaking operations performance before takeoff. An initial sequence obtained from ground controller. A heuristic algorithm that used in this thesis is a hybrid of constraint satisfaction and dynamic programming for minimizing sum of the total delays. The performance of the heuristic algorithm is compared with tabu search algorithm. The result shows that the proposed algorithm... 

One of the model based control strategies that has been proposed in recent years for the control of process systems is the one based on the economic models, in which objective functions with an economic basis are used along with the equations and constraints to perform control calculations. In this work, the control of a multiproduct continuous stirred reactors is discussed, in which, it is possible to produce different products based on changes in the market demand, the price of the products or the primary raw materials according to a specific schedule. One of the recently used methods is the economic predictive control method based on the Lyapunov function. In this method a quadratic... 

Multi core processors are becoming mainstream in the computation area, wide application of multi core processors in Engineering, Industrial purposes and scientific applications made them popular among users and Manufacturers, cloud computing is a very well known Concept which technically is a Multicore processing environment, most of Businesses, enterprises and engineering works nowadays are getting done by the help of cloud services, hence, to get the best of these multi core cloud computing systems, scheduling of the tasks on the cores and virtual machines(VMs) is necessary, which is the answer to two questions: each task must be assigned to which core(VM)? And What is the order of... 

Piping process is the most important part of industries projects which pay attention to construction and installation of industrial pipelines and its facilities. In the meantime, due to increasing demand of industrial units to construction and development projects, planing and scheduling the piping is necessary. We review and discuss various aspects of the piping process, optimization process and the related scheduling literature that is called Flexible Job Shop Scheduling Problem. Then, to solve the problem, considering the real world assumptions, a mathematical model, is developed and a heuristic algorithm is introduced. Also, in order to determine an appropriate bound for the optimal... 

The main purpose of this research is to consider the operational machine cost in the shop floor scheduling, which is not considered in the literature thoroughly. To this end, four types of problems in the parallel machine environment are studied with the objectives of minimizing makespan and total cost. Accordingly, the problems are as type of multi-objective optimization, so we choose the approach of finding Pareto optimal solutions to solve them. In these problems we have considered unrelated parallel machines, uniform parallel machines, and the cases of existence or non-existence of sequence dependent setup times and costs. In order to solve the problems, various approaches, with respect... 

In recent years, having an efficient supply chain has become an important element in the success of organizations. Attention to different aspects of the supply chain can have a significant impact on gaining a competitive advantage in the market. With the development of global markets, designing resilient supply chains has become a critical issue among businesses. The importance of this topic has prompted researchers and decision-makers to develop quantitative and qualitative models to reduce the damages caused by disruptions to supply chain systems. Various factors, including human and natural elements, can jeopardize the efficiency of supply chain systems. Therefore, supply chain systems... 

Software defined network (SDN) is an emerging network architecture in which the network control is directly programmed and separated from the forwarding plane. The SDN is a suitable and adaptable infrastructure for the requirements of new networks such as the Internet of Things and the fifth generation of mobile phones. In real time systems, tasks that miss their deadline are considered worthless or useless. Nowadays, real time applications in the SDN platform have diversified and will continue to expand in the future. SDN should be able to support real time communications like traditional networks, and even better. Therefore, from a designer’s or analyst’s point of view of such networks, it... 

Todays, given the existence of a strong competitive environment in the industry, supply chains should be quick and reactive, in addition to keeping their costs down. Transit warehouses and warehousing issues are one of the most efficient techniques that reduce inventory costs, while increasing the flow of goods and shorter transport cycles. Regardless of how a warehouse system is designed, the allocation and sequencing of input and output trucks to platforms is considered necessary. The inappropriate sequence of input and output trucks on the platforms increases the completion time of the operation. Also, the uncertainty and unpredictable circumstances of the real world make planning and... 

In recent years, heterogeneous architectures have been widely used in digital system design, so that these heterogeneous platforms are employed to achieve low power consumption, high performance, and high reliability. In other words, heterogeneous multi-core systems are promising solutions to provide a wide range of possibilities in compromising the low power/energy consumption, high reliability, and high performance. Most heterogeneous systems have several different islands (in terms of core types, supply voltage, and frequency) that each of them consists of several homogeneous cores. Due to the heterogeneity, the values of power consumption, and reliability of the tasks are differentt,... 

Access to global memory is one of the bottlenecks in performance and energy in GPUs. Graphical processors uses multi-thread in streaming multiprocessors to reduce memory access latency. However, due to the high number of concurrent memory requests, the memory bandwidth of low level memorties and the interconnection network are quickly saturated. Recent research suggests that adjacent thread blocks share a significant amount of data blocks. If the adjacent thread blocks are assigned to specific streaming multiprocessor, shared data block can be rused by these thread blocks. However the thread block scheduler assigns adjacent thread blocks to different streaming multiprocessors that increase... 

This research deals with a realistic cyclic three-stage supply chin consisting of one supplier, one manufacturer and one or more retailers, in FMCG environment. Orders from retailers are supposed to iterate over cycles and parallel machines are available to process perishable jobs with given release dates, due dates and deadlines. To start process of he jobs, perishable raw material, supplied by an external supplier, is required. Jobs are subject to post-production shelf life limitation and must be delivered to retailers during the corresponding time window bounded by due dates and deadlines. Both early and tardy jobs are penalized by partial weighted earliness/tardiness functions and the... 

Among various types of resources defined in the project scheduling literature, the most studies have been conducted on the renewable and nonrenewable resource types. Definition of different resources in the project scheduling literature is based on the specification of the resources in the real projects. Yet there are some sort of nonrenewable resources in the real projects that are not exactly similar to the type defined in the project scheduling literature. The difference stems from this fact that in the project scheduling literature, it is supposed that the nonrenewable resources required for the execution of the project activities are available in full amount at the beginning of the... 

We examined the Phase-Type distribution to calculate project activity duration and solve the resource constraint project scheduling problem with non-deterministic activity duration through meta-heuristic techniques. The activity usually doesn't have a fixed duration. The problem is caused by numerous factors that exist when carrying out a project, such as a lack of resources, late delivery of resources, and mistakes made by people. The literature review revealed that the scheduling problem had been thoroughly researched. The more accurate and realistic the activity duration estimates, the better the project planning and cost control. For this purpose, in this research, the duration of the...