Sharif Digital Repository

In the modern world today, the increasing need for transfering data in high speeds and long distances has encouraged the investors of this area to use more efficient technologies of this field. With regard to the need for extensive and scalable communication networks, reusing the bandwidth in closer distances seems to be inevitable. Hence, finding an optimal way of using resources like bandwidth and power is necessary. In OFDMA-based networks there is no intra-cell interference due to using orthogonal subbands and the most important limiting factor in designing these networks is inter-cell interference. Therefore in this thesis we are gonig to analyase the partial frequency reuse method... 

Due to the physical limitations of the conventional 2D ICs at Giga-Scale Integration, modern technologies have been emerged. Among them, through silicon via (TSV) - based 3D ICs have been used to continue Moore’s law in the interconnect era. In these systems, dies are stacked at z-direction after wafer thinning. Electrical connections between stacked dies are done by TSVs. One important advantage of 3D integration technology is their ability to stack heterogeneous systems with different technologies on a single chip. This will not only increase interconnect density but also will reduce the delay and power consumption. However, nowadays, fabrication and optimum design of TSVs are still big... 

Based on International Energy Agency studies, achievement of 450 ppm CO2-equivalent emission target in global emission means that the CO2 emissions in 2050 must be reduced to %50 of 2005 level, and this implies that a portfolio of emission reduction policies and strategies need to be exploited through current century.
At the present time, Carbon Capture and Storage (CCS) Technology is a dominant strategy among all the long-term carbon abatement strategies in many countries. Nevertheless, its potential as a climate mitigating option will be proved, only if it is implemented in the countries which are developing at a great pace and taking advantage of fossil fuels in order to afford their... 

Today, considering the global demand for reducing greenhouse gas emissions, rechargeable batteries are considered as a source of energy in electric vehicles, hybrid electric vehicles and smart grids. In all these applications for secondary batteries, the battery management system requires an accurate estimate state of charge of each cell. However, this estimate is difficult particularly for battery aging. In this study, a lithium-ion battery is modeled by using multidimensional multiphysics modeling and simulated in a comsol. In this simulation, the effect of the thermal conductivity coefficient on the battery temperature, initial salt concentration in electrolyte and the rate of discharge... 

The main goal of partake quake-attenuating in buildings is to absorb energy and to attenuate the exerted forces into structures as a result of ground motions. Notwithstanding achievements and developments in the field of dampers production, applying of dampers in structures is proportional to following complicated technology and subtle engineering. Installation and initiation of dampers depend on educated and expert crew; moreover, such attenuating systems need maintenance and repair during the useful structural life time. Therefore, nowadays civil engineering suffers from the lack of such quake-attenuating systems to be able to respond simply but applicable mechanism at the same time for... 

Scientific studies, conducted over the world, show that an immense portion of pollutants and greenhouse gases emission to the atmosphere are the direct result of the incineration of fossil fuels in industrial units. These industrial units include chemical industries, power plants, metal industry, etc. Therefore, there is a tremendous necessity to reduce the pollutants emission from these industries immediately and effectively. Meanwhile, in order to mitigate the emission to the atmosphere, there should be a meticulous estimation of pollutants emission from various sources. Hence, in a project called "standardization of emission of pollutants from diverse industrial units in Iran", the... 

Climate change and energy security are key drivers for future energy policy. While energy security has been a pillar of energy policy for about a century, concern about climate change is more recent and is bound to radically change the landscape of energy policy. Policy makers are now under increasing pressure to address these twin challenges: to develop cost-effective policies that will both ensure the security of our energy system and reduce greenhouse gas emissions.
Main Effort in this Project is to construct an integrated model of Iran’s energy system to serve as a policy analysis tool, by which policymakers are able to identify the future effects of a wide range of policies in... 

Evaporative cooling systems are of most common cooling systems which their electricity consumption is much lower than vapor compression cooling systems. Enhancement of these system’s performance could help to propagate these systems and also decrease the electricity consumption and corresponding emissions in large scale. In this thesis, first a modified cycle is proposed for evaporative cooling. Then, in order to use evaporative cooling in humid climates, a desiccant wheel is implemented in this modified evaporative cooler. As using evaporative cooling will cause high water consumption, a novel cycle is proposed for desiccant based evaporative cooling which is able to cover system water... 

Globally energy system is the main source of green house gas emission. 60-90 percent of manmade CO2 is due to energy sector. Pollutants like NOx, CO, Non Methane Hydrocarbons which may cause indirect effect on climate system are mainly emitting from energy sector. Gas, Oil and Coal extraction and transmission are responsible for more than 15% of Methane emission globally. Therefore it is important to consider all types of GHGs emission as well as all sectors of energy system to assess the GHGs mitigation potential throughout the energy system. Considering the significance of energy sector in GHGs emission, in this study we developed an optimized model for Iran’s energy sector in which we ran... 

The release of toxic materials causes tragic accidents every year. There are various techniques in order to mitigate the release effect of these materials such as Application of air jets, steam curtains and water curtains. In this study first, previous works are reviewed in order to select the best technique for the mitigation of heavy toxic gas release. Then CFD modeling is used to simulate this technique.
A field situation in which chlorine gas was released upwind of water spray was simulated using the open-source software FDS (Fire Dynamic Simulator), a CFD model. Only mechanical effects of water sprays are considered; hence the effect of absorbtion is neglected. Finally tha... 

Natural disasters take many lives each year and leave many others homeless, thereby occupy governments to restore previous conditions rather than deal with progress. Iran has also a worrisome record of natural disasters, and the unpreparedness of the parties involved turn each of such event into a disaster. The purpose of this study is to estimate more accurately the outcomes of severe earthquakes, and show its effect on the decisions which are made to mitigate them. The losses are classified into three groups of immediate, short-run and long-run, which are then measured by some common quantities. Using the 2003 Bam Earthquake as a reference, these quantities are used to measure the... 

Oil and gas industries are always considered as one of the most polluting industries in the world. Many pollutants are emitted from the industry into the environment every year. Equipment’s leak and flaring off additional gases produced by various processes of oil and gas production are the main sources of waste in these industries. In order to control these hazardous wastes, it is necessary to provide effective solutions and make appropriate decisions so policymakers will be able to implement policies in order to reduce the emissions of air pollutants. In order to reduce the emissions, it is necessary to conduct the correct and reliable methods and have sufficient information about the... 

The release of toxic materials causes tragic accidents every year. There are various techniques in order to mitigate the release effect of these materials such as Application of air jets, steam curtains and water curtains. This study presents numerical calculations to reproduce the continuous ammonia release dispersion with and without the mitigating influence of a downwind water curtain using computational fluid dynamic (CFD) software ANSYS Fluent 15.0. The RNG model coupled with Lagrangian discrete phase model (DPM) was used to simulate the dilution effectiveness of the water curtain system. The ammonia absorption was taken into account by means of user-defined functions (UDF). The... 

Expansion of using social networks for reading and sharing news on the one hand, allows for quick and easy access to the news, but on the other hand, increases the spread of fake news and misleads many users. Therefore, identifying the fake news and attempting to mitigate its spreading on social networks is one of the major research areas in recent years. An important issue in this regard is reducing the time gap between news release time and identifying it as fake and starting to take action. Many researches has been done on detection of fake news, but since there is a trade-off between minimizing the time gap and maximizing accuracy, work on these models continues. There are also different... 

Earthquake is one of the deadliest natural hazards that has taken more than 400 thousand lives, only in the last decade. Iran is one of the countries that are at high risk of potential death toll resulting from such hazards, firstly because it is located in a potentially high-risk zone, the so-called earthquake belt and, secondly because of its problems in the management of disastrous situations (especially, pre-disaster management). Bam 2003 earthquake is one of the most painful experiences in this context. So, in this research, emphasizing on the practical use of optimization models, an existing model is applied on the damaged area of the Bam earthquake. The mentioned model considers the... 

Release of toxic gases and hazardous materials is very dangerous for health of people that presence in near of release places. Whereas if the concentration of some toxic materials is more than a definite limit, it may cause of irreparable hurt to health of people in very short times, hence reduce the concentration of released materials can get the time for refuge in safe sites for people that presence in released site in initial times.
In this paper with use the Computational Fluid Dynamics models the effect of fence in reduce the concentration of dense gases and delay the distribution of these gases has been studied. The two toxic gas (chlorine and methyl-isocyanate ) have been... 

Annually Natural disasters make tremendous impacts on societies. Fatality rate of earthquake in Iran is almost more than all other disasters. There are numerous problems in disaster Management's of Iran and other countries. One of the disaster Management's phases is response phase which mostly depends on emergency processes, so most of papers working on this phase, plan for emergency state by using different techniques.All the studies seeking the response phase, try to reduce the loss of disaster by the use of immediate response to earthquake, pointing the disaster after occurrence. But Another point of view is to make loss reduction by precautious activities and plans. Actually, the loss... 

Nowadays, Information Security is one of the most challenging issues in organizations. With the development of technology and the Internet, people insist on greater access to information and data. In addition to creating value-added for the organization, collecting a huge amount of data in the organization's database and using IT tools threat it by losing the funds and credibility obtained from customer confidence in different ways. Therefore, managing information security is necessary due to the current competitive environment. In spite of the advancement of technology, the existence of many complexities in this subject led to the growth of security incidents. Hence, the organizations’... 

The objective of this thesis is to prioritize a portfolio of buildings for seismic retrofit. A new set of sensitivity measures is proposed to rank the buildings in accordance with the reduction in the loss of the entire portfolio. To this end, various risk measures are differentiated with respect to the cost of retrofit for each building. These risk measures are the moments of the portfolio cost probability distribution which imply the risk-neutral and risk-averse decision making. Two costs are considered: Construction cost due to retrofit and repair cost due to structural and non-structural damage. To quantify the risk, reliability methods are employed in which many interacting... 

Use of nano-scale VLSI technologies in the fabrication of System-on-Chips (SoCs) makes reliability as one of the major issues in the design and implementation of these products. SoCs are susceptible to several fault sources such as crosstalks, cosmic particle strikes, electromagnetic interferences, and power supply disturbances. Among the mentioned fault sources, crosstalks have the major contribution in threatening the reliability of SoCs. This thesis addresses the modeling and mitigation of crosstalk faults. In this regard, two analytical models and three crosstalk reduction methods have been introduced. The proposed analytical models, which have been introduced in the fourth chapter of...