Sharif Digital Repository

Data transmission consumes most of the power resources in wireless sensor networks. Con-sequently, a large number of methods have been devised to cope with this problem. In this thesis, we propose a data reduction algorithm based on the transmission workload of interme-diate nodes. We aggregate the incoming packets to the intermediate nodes into one packet by employ ing the Principal Component Analysis (PCA). Therefore, each intermediate node only sends one packet in stead of relaying all the incoming packets and hence we achieve consid-erable reduction in power consumption at those nodes. Although this approach imposes some delay for buffering the incoming packets, but extending the... 

Limitations of fossil energy resources and environmental factors such as gas emission and global warming, forces human being to tend to apply renewable energies especially solar energy resource. Iran, which is located in yellow belt of the earth, has a high potential to be benefited from solar energy. Since more than 40 percent of energy resources are consumed in the building section, using solar energy I buildings can help the country to reduce the energy consumption. Space Cooling and heating and water heating are some examples of solar energy applications in buildings. Because, there are various types of climates in the world, there is not a unified code and guideline to design and... 

Electric Arc Furnaces" are of the most important industries in energy field. High energy consumption leads us to improve model for optimizing energy demand in electric arc furnaces. Melting and refining are two processes which need high amounts of energy. There are several different energy resources in electric arc furnaces. Materials can receive energy from electric arc or from chemical reactions that takes place between molten steel and slag. In addition, some slag formers should be added to the furnace. There are complicated relations between mass transfers, heat transfer and energy balance in EAF. In order to solve energy conservation problem in EAF, we should first extract equations to... 

Reducing energy consumption is one of the challenges facing wireless sensor networks with many solutions introduced for them with each having advantages and disadvantages. Some of the solutions introduced are based on using movable sinks. In this project, we attempt at proposing a place for the establishment of sinks using genetic algorithm that can reduce energy consumption in the net knots and increase the net life. This work should be done after reviewing the results of past researches and introduced methods. We will analyze the practicality of the proposed model using simulation and will show their advantages over the previous mentioned methods  

Energy management in buildings play an important role in minimizing the global energy consumption. Providing an optimal temperature in buildings and workplaces is a significant step toward the energy management, regardless of the local climate. Buildings account for 20-40% of the world’s total energy consumption, and this consumption is increasing in developed countries at 0.5-5% per annum.In various studies, energy consumption potential has been investigated using model predictive control (MPC) and system identification.In this paper, the building system is modeled as a gray-box model in which the formulas are developed using the heat transfer equation and the solar radiation heat is... 

IoT-based systems use cloud computing servers that are generally far away from them to perform tasks. Whenever there is a computational task that requires heavy and complex processing, the problem of offloading decision is to identify the best computing server to perform the processing related to this task. Numerous dynamic factors affect the solution to this problem.Optimization in energy consumption of the device that has generated a task alongside reducing its calculation delay can be applied in solving the offloading problem. The optimization problem that is formed to minimize the energy consumption in the offloading decision is an integer programming problem that is generally difficult... 

One of the main challenges in the design of wireless sensor networks (WSNs) is minimizing the energy consumption while simultaneously maximizing the performance of sensors. In this thesis, we have considered WSNs based on beacon enabled IEEE 802.15.4/Zigbee Standards with low rate applications like temperature, humidity and light sensing, which mainly have been used in a smart home environment, and proposed a cross-layer design to overcome this challenge. The design involves an optimizer module that captures the application layer and MAC sub layer behaviors. Based on these behaviors, the optimizer dynamically changes the rate of node’s traffic at the application layer and the priority of... 

Solar panels are still rather expensive equipments. At current electricity prices, it takes several years to return the investment made to install them in a household. Smarter use of their produced energy can help reduce this break-even time, and hence, would motivate more households to be willing to install and use them which would finally result in a more sustainable society with less reliance on fossil fuels. Electricity prices usually differ at different times of day with the common, but unfortunate, property that the price is maximized at evenings when the solar energy production is minimal or non-existent while at the peak production of the solar panels, i.e., around noon, the price is... 

Virtualization has provided good and efficient use of resources in today datacenters. In this environment, modules of multi-tier applications can run on several Virtual Machines (VMs). VMs that are dedicated to a module often need to transfer data among themselves, and also to the VMs in other modules, and hence, the overall application runtime may be increased if the communicating VMs are put on far physical machines; consequently, servers must be up for a longer time and will consume more energy. Consolidating several VMs on a single Physical Machine (PM) effectively reduces the total computing power consumption, but we show that it is also important to consider the above inter-VM... 

Wireless Body Area Networks(WBAN) consist of some sensor nodes placed in or inside the body and reportmedical data to a central node. The most important application of WBANs will be in medicine for monitoring of patients. In this applicationthe battery not only occupies a significant volume in the node but also itcan’t be changed easily,specially in implanted nodes case. On the other handas WBAN is used to report vital information, it should be reliable. Hence, the most important issues in WBAN design are both energy constraint and reliability requirement. Most of works in the literature, utilize Time Division Multiple Access (TDMA) with a central node to dynamically control the transmission... 

Smart consumers have a major role in the development of the smart grid. On the other hand, increasing need for more flexibility in DGs highlights the consumer’s role. This is possible with the development of smart appliance and appropriate communications infrastructure to active consumers. Today, with the development of smart grids, it is possible to control different parts of home energy systems and manage energy consumption. In this project a comprehensive model has been developed to optimize energy consumption in smart home. In the next phase of the thesis, due to the random nature of solar energy and electric vehicles, stochastic model of smart home energy system is discussed. At this... 

The exit flue gas temperature of conventional gas fired boiler is generally high and considerable energy is lost to environment. Therefore, new methods are needed to recover water and heat from boiler flue gas in order to reduce overall plant water consumption as well as to increase energy efficiency and mitigate detrimental emissions. This project involved design of a heat and water recovery system including condensing heat exchangers to be used in residential buildings. In this project based on simulation of heat and water recovery system the recoverable amount of heat and efficiency improvement potential at various conditions such as different exit flue gas temperatures and different... 

Optimization of energy consumption is generally important in mobile networks and in particular in automotive networks. One of the challenges of installing roadside units in automotive case networks is to provide energy to the equipment assigned to these units. In some cases, power is easily available, but in many places, the cost of energy is very high and does not have economic justification. Therefore, optimization of energy consumption in roadside unit is of great importance. Typically, vehicles limitations in terms of energy consumption for communications are far lower than that of a roadside unit. In this dissertation, part of roadside communication to vehicles is shifted to the... 

The energy consumed by lighting, heating, ventilating, and air conditioning (LHVAC) systems have been increasing over the last decades. Thus, improving the efficiency of LHVAC systems has gained the attention of industry and academia. This concern has posed challenges for controlling and optimizing LHVAC systems. The traditional methods, such as on/off and PID approaches, usually involve conditions and parameters that may not hold in practice since LHVAC systems are complex, nonlinear, and dynamic. Also, controllers are one of the important components of a method for its efficiency. This research focuses on controlling LHVAC systems. Fuzzy logic controllers one of the best controller for... 

Buildings account for more than 30% of the world’s total energy consumption. Among building end-uses, air conditioning and in particular cooling systems have a major share of more than 50%. Therefore, design of optimal controllers for AC systems has become increasingly important. Classical and model-free control methods typically lack the ability to optimize energy consumption. On the other hand, model-based optimal control methods rely on precise modeling, which is difficult to acquire due to the complexity of the AC system dynamics.In recent years, deep reinforcement learning has become a popular choice for optimal control of systems with complex dynamics. In this thesis, a deep... 

Abstract In this study, by using panel instrumental variable quantile regression method (IVQP) and household budget data during the years 2011-2018, income elasticity of Housing energy has been estimated at different levels of energy expenditure. This method helps to study the whole energy expenditure distribution instead of focusing on the average effects. The study results show that income elasticity has a downward trend with increasing energy consumption quantiles. In other words, households with higher consumption have less income elasticity, so that the income elasticity is estimated for 10, 90 percentage, 0.47, and 0.32 quantiles, respectively. Also, in another part of the research,... 

One of the main methods to reduce fuel consumption and emissions is using renewable energy resources. This research proposes a hybrid renewable energy system on a container ship which includes one photovoltaic solar system, and one kite system. The photovoltaic system produces a part of the ship's electric power consumption and the kite system produces propulsion force using wind energy and transmitting this force to the ship through towing rope. Different components of these renewable energy systems are connected with the internet of things technology. In the internet of things structure design section, in addition to the conceptual design of different layers with emphasis on the processing... 

With the expansion of industrial Internet of Things systems in automation, control, and monitoring processes, the need for powerful servers for real-time processing, calculations, and decision-making in large-scale applications was felt, and implementation and use of this in such applications was one of the problems in this field. The base of this problem was also caused by its central structure, where processing, calculations, and decision-making took place in a central server, which even caused the existence of other risks like security and resilience problems against disconnecting the server layer with sensor and actuator layer and also hacker attacks on the central server.To come over... 

This research aims to explore the effectiveness of past tariff evolutions in shaping firms' response to current input prices. Additionally, it investigates how asymmetric fuel pricing across different industries influences overall industry efficiency and prosperity. Furthermore, the study examines the impact of fuel subsidies on the equilibrium distribution of companies independent of welfare decline. In Chapter 1, utilizing microdata from Iranian industrial workshops between 1386-1396 (2007-2017) A key finding is that new firms exhibit a significant and stronger reaction to energy price variations compared to other firms when it comes to technology choices.Chapter 2 presents a structural...