Sharif Digital Repository

Wireless sensor networks (WSNs) are tiny devices with limited computation and power supply. For such devices, data transmission is a very energy-consuming operation. Data aggregation eliminates redundancy and minimizes the number of transmissions in order to save energy. This research explores the efficiency of data aggregation by focusing on different aspects of the problem such as energy efficiency, latency and accuracy. To achieve this goal, we first investigate data aggregation efficiency with constraint on delay, which can be compatible with other important system properties such as energy consumption and accuracy. By simulation, we will show that, depending on the application, we can... 

Due to increase of industrial plants and development of cities in the world, there is an increase in demand for all types of energy, especially fossil fuels.Consequently, energy related decisions have become an important factor in national and international political decision makings. Regarding to remarkable effects of energy decisions on economical, industrial, political, social and environmental aspects of our country and considering the importance of energy management in our country as an energy-based country, we have focused in this research on studying several energy management systems (national and international systems) and made an assessment on their applicability and effectiveness.... 

WBAN , as one of the most important wireless networks in the near future, has received significant attentions in recent years. The most important designing challenge in these networks is the scarcity of energy resources especially in their sensor nodes. Additionally, special characteristics of these networks have led the other network’s designs, especially the general sensor network protocols to be inefficient for the WBAN. Among others, the existences of recurring patterns in each sensor channel fading and the high correlation among different sensor channels are some of the most important characteristics of WBANs. Considering these characteristics, in this thesis, the MAC sub-layer of... 

The ever increasing density and performance of FPGAs, has increased the importance and popularity of soft processors. One major research concern in this regard lays in the field of energy efficiency of the system on FPGA. This work is particularly focused on the energy efficiency of multiprocessor structures on FPGA using system level techniques. The growing gap between the speed of processors and memories can partly be compensated through memory hierarchy, i.e. caches. Since memory accesses follow a non-uniform distribution, and vary from one application to another, variable set-associative cache architectures have emerged. In this thesis, two novel cache architecture, primarily aimed at... 

As far as reliable supply and cost-effective methods of power delivery to end-users are concerned, new advancements in smart grids and, in particular, smart pricing are of high significance to grid operators. In the recent decade, there has been a considerable raise in penetration of renewable energy resources and also the number of hybrid electric vehicles which can act as a huge mobile storage in the network. Hence, finding a practical and cost-effective method of management of all these new resources and avoiding potential problems associated with them seems to be of high importance. In this study, first, the response of demand to pricing signals has been modeledAfterwards, the response... 

Shortage of energy sources in the new decade along with the increasing level of greenhouse gas emissions urges researchers in the field of energy to explore for the new source of energy as well as seeking for methods for usage of available energy resources more efficiently. Therefore, development of building with low level of energy usage may significantly reduce the need for grid energy. This can be met with new construction materials to reduce the energy consumption, using renewable energies sources such as solar and wind as well as design and development of materials with capability to store energy. The use of materials which can store energy and release it when needed has been considered... 

With a growing concern on the considerable energy consumed by data centers, research efforts are targeting toward green data centers with higher energy efficiency. Networks are essential to today’s highly instrumented and connected society. Currently responsible for a fraction of the energy the IT sector consumes, networks rely on equipments that often use a constant amount of power regardless of their utilization; a worsening scenario as traffic is expected to increase by a factor of three in the next few years. Datacenter networks, for instance, employ devices that consume several kilowatts of power even when idle. This work aims to improve the energy efficiency of datacenter networks by... 

Today, building sectors account for 34% of total energy consumption in Iran. Increasing demand of the comfort level along with population growth necessitates much more attention about energy requirements in the country. Such phenomenon has already raised concerns about the heavy environmental impacts. The present research studies minimization of global warming potential effect for an educational building by developing life cycle optimization model. The Department of Engineering of Sharif University of Technology is selected as the case study and optimal solutions has been achieved for this building. Results state that implementing cogeneration and renewable energies can reduce20 -25% of the... 

Several applications have been envisioned for wireless sensor networks (WSNs). These range in scope from military applications to environment monitoring to biomedical applications. It is a widely accepted fact that the limited energy available at the nodes of a wireless sensor network must be used as efficiently as possible. If energy conservation techniques are used at different levels, the functional lifetime of both individual nodes and the network can be extended considerably.
Energy can be saved if the network topology itself is energy-efficient. The research in topology construction and connectivity has been approached independently along two paths. In one path, researchers aim to... 

Energy efficiency for Iran, which has large reserves of oil and gas but also has a high energy consumption is important because it ensures the country's energy security and saving each energy unit creates energy exports opportunity. Buildings have high energy saving potential; this sector uses about thirty percent of energy consumption (about half the gas and thirty percent of the annual electricity consumption). Households are not motivated in saving energy because government pays energy subsidy. In this research building energy consumption (in Tehran) modeled by bottom up approach. Then the effect of economic incentive tools such as subsidy, loan and tax on motivation in energy saving... 

Reviewing trends of energy consumption in the world reveals that sooner or later energy resources will be depleted. This concerning rate of consumption has brought about more greenhouse gases (GHG) emission influencing deleteriously on environment and climate. Human has continued energy consumption to maintain and improve the quality of his life through industrial production. Industry as a significant energy user owns considerable contribution to this consumption. Several attempts have been carried out to develop energy management systems in order to improve the energy efficiency of industrial sectors. Whilst they are comprehensive and could be applied to any sector, there is lack of... 

Wireless Sensor Networks (WSNs) have attracted much attention in recent years for their unique characteristics and wide use in many different applications. WSNs are composed of many tiny sensor nodes that have limitations on energy level, bandwidth, processing power and memory. Therefore, reducing energy consumption and the increased network lifetime and scalability are the main routing challenges in sensor networks. Many algorithms were presented for routing in sensor networks; a class of theses algorithms is hierarchical algorithms based on clustering. Their main goals are to reduce energy consumption, distribution energy consumption in the whole network and increasing scalability. There... 

Wireless sensor networks have many applications one of which in linear structure is used to control pipeline infrastructure. This thesis focuses on the routing of oil, gas, and water pipelines using wireless sensor networks. There are two algorithms one of which is Jump Always (JA) Algorithm and the other one is Redirect Always (RA) Algorithm. There are designed in Linear Structure of wireless sensor networks that are presented with a hierarchical addressing scheme. A Redirect Jump (RJ) routing protocol is our method that is designed for the hierarchical addressing scheme too. The RJ routing protocol has many benefits compared to the two methods (JA and RA). The RJ algorithm can increase the... 

Wireless Sensor Network (WSN) is a rapidly growing technology that is used to meet different requirements of a wide range of applications. Energy conservation is one of the main design challenges in WSNs due to limited energy resources. Routing plays a significant role for energy efficient communication in WSNs. Although there are many research studies that utilize energy efficient routing to conserve energy in WSNs, there are a few works that took advantage of machine learning techniques for saving energy through energy efficient routing.The main goal of this thesis is to indicate that machine learning is a functional approach to many problems in WSNs. To fulfill this goal we first... 

Based on fog computing paradigm, new applications have become feasible through the use of hardware capabilities of smart phones. Many of these applications require a vast amount of computing and real-time execution should be guaranteed. Based on fog computing, in order to solve these problems in is necessary to offload heavy computing to servers with adequate hardware capabilities. On the other side, the offloading process causes time overhead and endangers the real-timeliness of the application. Also, because of the limited battery capacity of the handheld devices, energy consumption is very important and should be minimized.The usual proposed solution for this problem is to refactor the... 

Energy constraint is the most critical problem in wireless sensor networks (WSNs). To address this issue, clustering has been introduced as an efficient way for data aggregation and routing. However, there also exist some disadvantages associated with the clustering scheme, such as additional overheads during the cluster-head election and cluster formation process. Most available clustering algorithms do not efficiently take into consideration the geographical information of nodes in the cluster-head election. This leads to uneven distribution of cluster-heads and unbalanced cluster sizes, which brings about uneven energy dissipation in clusters. In this research, an Efficient Distributed... 

Rapid growth and proliferation of cloud computing services around the world has increased the necessity and significance of improving the energy efficiency of could implementations. Virtual machines (VM) comprise the backend of most, if not all, cloud computing services. Several VMs are often consolidated on a physical machine to better utilize its resources. We take into account the network structure of the data center hosting the physical machines when consolidating the VMs so that fewer racks and routers are employed, without compromising the service-level agreements, so that unused routing and cooling equipment can be turned off to reduce energy consumption. Our experimental results,... 

In this thesis the superstructure of continuous monitoring system has been developed to help energy service companies’ network. Suggested superstructure consists of three main sections: data acquisition, data analysis and decision-making, optimizer. Historical data and data which picked up by sensors are imported in decision support tool. Input data are analyzed by technical, economical and environmental models and converted to actionable indicator for best management of the project to promote energy saving project. Because the ESCO income obtained from the energy saving project, development of analytical decision support tool will help ESCO to evaluate the procedure of the project.... 

Due to rapid growth of energy consumption in recent years, extensive efforts to improve energy efficiency in production and consumption sectors have been done in order to reduce energy consumption in these sectors. The primary assumption is that improving energy efficiency has a one-to-one impact on reducing energy consumption, but in practice this is not true in all cases. In fact, by elevating energy efficiency, the cost of energy services is decreased and, thus, remained accessible income is increased. This issue will increase the demand for all energy and non-energy commodities, therefore, it will have influence on their supply. The effects of this variation in supply can be spread in... 

Wireless Sensor Networks (WSNs) have developed in recent years and are used in many different applications such as fire detection, military operations, and healthcare. Sensor nodes can sense an environment, sending and receiving information and forwarding packets from source nodes to a sink. These tasks consume large amounts of energy. In many WSN applications, delay and reliability of data delivery and the energy consumption of nodes are important design metrics. Network protocols such as medium access control (MAC) and routing should be designed to improve these metrics In this thesis, we propose a new cross layer algorithm that improves the performance of WSN networks based on these...