Sharif Digital Repository

During the last few years, utilization of distributed generation (DG) in power systems has been widely increased. This trend has magnified studying the effects and impacts of DG on such systems. One of the benefits of DGs in a power system is loss reduction. If determining DG size and place is done properly, the loss of the network can be minimized. Another way of reducing loss in distribution network is by reconfiguring the network. During the reconfiguration, constraints like being radial, avoiding load isolation as well as voltage/current limitations must be taken into consideration. Taking these constraints into account makes reconfiguration an optimization problem. In this project, the... 

One of the most important technologies in space missions is capability of moving satellites together with a predefined structure (virtual structure). This structure can reconfigure itself to any desired space mission and it is known as reconfiguration maneuver, in this maneuver all of the satellites have to follow needed virtual structure from any initial configuration to any desired second composition. In available virtual structure methods, there are a lot of limitations in maneuver because of algorithm constraints, in this project we try to extend available algorithm in virtual structure method and reach an algorithm which can start from any initial condition and complete the maneuver in... 

Network-on-Chip (NoC) is a promising on-chip communication paradigm which targets the scalability and predictability problems of the traditional on-chip mechanisms. However, it has been shown that, in future technologies (especially 22 nm technology), the power consumption of the current NoCs is about 10 times higher than the power budget can be devoted to them. Application-specific optimization is one of the most effective approaches to bridge the exiting gap between the current and the ideal NoC power consumptions. However, almost all existing application-specific customization methods try to customize NoCs for... 

According to power limitation on a chip and the need to simultaneously access high utilization and low power consumption, Multi-Processor System-on-Chip (MPSoC) architectures have been introduced. The major part of power consumption in a network on chip belongs to interconnects. One of the most important issues is to decrease power consumption while maintaining high utilization. The ability of optical interconnects in decreasing power consumption and increasing utilization has introduced a new architecture called optical network on chip. This architecture uses the benefits of optical signals and elements in order to transfer data. In this thesis, we introduce a new architecture with... 

In this research, it has been trying to implement Virtual Structure method for formation flight of multiple spacecraft. In this method, a virtual solid frame with virtual center of mass is considered and agents are arranged in a formation with respect to the virtual center. In this work, a formation keeping control system is implemented in which a feedback from formation to virtual structure and vice versa is considered. The method is implemented firstly in a nongradient field and then developed into a circular orbit in order to investigate the in-orbital effects. An algorithm for collision avoidance, based on relative distances and relative velocities, was also developed. The algorithm was... 

This project introduces a topology enabling a Low-Noise Amplifier (LNA) not only to attenuate the unwanted signals at the input stage but also to satisfy the input matching requirement in an ultra wide frequency band. Moreover, a single ended to differential signal conversion method is proposed. This method employs a noise reduction idea, so it has a lower noise figure compared to the other introduced methods with the same purpose. The introduced methods have been utilized in designing two 0.18μm reconfigurable CMOS LNAs. One of the designed LNAs covers 2.3-3.6 GHz band width and the other one covers the UHF (470-860MHz) band. Stringent sensitivity requirement, presence of strong in-band... 

The shrinkage of feature sizes has resulted in global wiring delays being the bottleneck in on-chip interconnects. As a consequence, Network-on-Chip (NoC) emerged as a desirable interconnect structure between Processing Elements (PEs) on a chip. On the other hand, due to the non-uniform communication patterns among PEs, it is beneficial for the routers input ports to have a reconfigurable buffer structure. Having this in mind, we proposed a reconfigurable microarchitecture for on-chip routers which is able to reconfigure the Virtual Channels (VCs) in input ports, without lowering the clock frequency of the router. For this purpose, we presented a simple and efficient mechanism for monitoring... 

One of the topics that has been given great consideration after restructuring and smart grid emergence, is loss management. This subject is specifically important in distribution systems, which have been reported to have 70% of the total loss in power systems. In this thesis, distribution loss is studied and its affecting factors are analyzed. Then loss optimization and loss cost allocation to distribution consumers are studeid. In order to acheive these two goals, it is neccessary for the distribution system to have the capabilities of a smart grid. The subjectof distribution reconfiguration is duiscussed as one of the loss reduction methods. Traditional reconfiguration problem trend... 

Feeder reconfiguration is one of the most prominent tasks for loss reduction, reliability improvement and also congestion alleviation in distribution networks. Besides improving abovementioned operational issues, during a long period of time, proper switching in appropriate times can causes a lot of economic savings. Furthermore, it can be intensified when capacitors are implemented and controlled in the network. To reach this purpose, most of the previous literature focuses merely on the power grid reconfiguration. Few of these researches have considered this problem as a dynamic one and studied that in a period of time, e.g. one day, considering fixed level of loads despite the others that... 

Nowadays, in the presence of different types of computer attacks and different methods of eavesdropping on network communications, nobody can deny the importance of cryptography. Hardware Security Modules that are specifically designed for this purpose are widely used as a fast and reliable tool for encrypting data in computer networks. In this project, using the common and well-known FPGA platform and by leveraging the reconfigurability feature of this platform and also by adding a network protocol detection module to the traditional architecture of Hardware Security Modules, a novel module has been designed and implemented that can encrypt and decrypt data in a communication network, at... 

Graphics Processing Units (GPUs) employ a scratch-pad memory (a.k.a., shared memory) in each streaming multiprocessor to accelerate data sharing among the threads in a thread block and provide a software-managed cache for the programmers.However, we observe that about 60% of GPU workloads of several well-known benchmark suites do not use shared memory. Morever, among those workloads that use shared memory, about 42% of shared memory is not utilized, on average. On the other hand, we observe that many general purpose GPU applications suffer from the low hit rate and limited bandwidth of L1 data cache.We aim to use shared memory space and its corrsponding bandwidth for improving L1 data cache,... 

In this dissertation, the value of distribution network reconfiguration in presence of distributed generation is investigated. In the first step, a mathematical optimization model is devised to minimize daily network losses via applying hourly reconfigurations. The results show that the hourly reconfiguration reduces the losses. Then, sensitivity analyses on the renewable penetration, wind and load correlation, switching cost and wind power prediction are conducted and discussed. The switching cost analysis revealed that a great amount of loss reduction could be attained with a small number of switching operations. The worthiness of reconfiguration becomes more in systems with high... 

Today with the deployment of cloud computing and web applications; We need to have powerful datacenters with provisioning high bandwidth. Current data centers with electronic network interconnects, using excessive power to provisioning requisite bandwidth. Nevertheless, interconnecting networks in data centers isn’t in maximum efficiency and many components of them aren't used efficiently. So it is necessary to use an optical network with dynamic provisioning variable bandwidth and energy management. In this approach, our proposed architecture is designing topology with adopting dynamically for energy management in optical interconnect networks in data centers. To achieve this we can study... 

Necessity of uninterruptable electricity supply is one of the most fundamental needs nowadays. To achieve this, power system are designed and operated based on adequacy and security metrics which are based on reliability. Despite efficient influence of these metrics in normal condition, they do not have appropriate function while facing natural weather disasters. Since these events are low probability, these event do not affect adequacy metrics incredibly. Additionally, reliability metrics are compute base on intrinsic failure rate of component while each weather disaster causes specific failure rate. Furthermore, number of failures in such events is too many to be handled by N-1 operation... 

Proliferation of distributed energy resources and the developing of smart grid concepts are of a great importance. This, however, influences the future of power systems and necessitates more studies in order to cope with the changes. In this regard, uncontrollability issues are arised by introducing the renewable energy resources in the power systems. To address this issue, energy storage systems are used to mitigate negative consequences of using renewable energy resources. Accordingly, in this thesis, a new framework for determining the capacity and location of the energy storage systems is proposed. In addition, reconfiguration of distribution network is also concerned in order to... 

Deep Neural Networks (DNNs) are widly used in various domains, such as medicine, engineering, industry, financial markets, mathematics and management. DNNs are composed of several layers, such as convolutional and fully connected layers. Increasing the number of layers in DNNs provides different application with their required accuracy. In recent years, there have been many accelerator aiming to execute DNNs. However, the high computation and memory demands in DNNs are the main challenges to execute DNNs. To reduce computation and memory requirements, various methods such as pruning and quantization, have been proposed. Pruning and quantization methods make the DNNs sparse and increase the...