Sharif Digital Repository

Age-related macular degeneration (AMD) is the most common cause of vision loss in those aged over 50. There are two main types of AMD, Wet and Dry form. Wet AMD is more severe though more treatable. There are three conventional treatments for AMD including laser therapy, surgery and intravitreal injection of anti-VEGF into the eye. Delivery of drugs to the posterior segment of the eye is still challenging and several implants and devices are currently under investigation for their ability to stimulate the retina, producing visual percepts. The application of intravitreal bevacizumab (Avastin) has expanded tremendously from the time of its introduction into ophthalmic care since 3 years ago.... 

Age-related macular degeneration (AMD) is the most common cause of vision loss in those aged over 50. There are two main types of AMD, Wet and Dry form. Wet AMD is more severe though more treatable. There are three conventional treatments for AMD including laser therapy, surgery and intravitreal injection of anti-VEGF into the eye. Delivery of drugs to the posterior segment of the eye is still challenging and several implants and devices are currently under investigation for their ability to stimulate the retina, producing visual percepts. The application of intravitreal bevacizumab (Avastin) has expanded tremendously from the time of its introduction into ophthalmic care since 3 years ago.... 

In this project, a comprehensive methodology is developed to present the lifetime management and optimization framework for hybrid renewable energy systems. The main purpose of this work is to minimize the lifetime cost and improve the system reliability based on the interaction between different optimization levels related to different steps in the system lifetime. The proposed methodology is generally presented by providing a connection between the three specified optimization levels: 1) Planning: including design and long-term optimization models which is performed before system operation, 2) Real-time operation: By employing the receding horizon optimization which is applied from the... 

Aging Aircraft with life extension, Conversion or replacing them with new aircrafts are of the decisions in front of airliners after their retirement. Decision making for repairing aircraft to increase its life is depended upon various parameters like its cost and reliability. The thesis evaluated the reliability of the structure of an aircraft before and after life extension. For this purpose, using the statistical data, the predominant failure modes are studied and based on these failure modes the border between fracture and health of the structure which is called limit state function is defined. After this using first order reliability method (FORM), the probability of the failures is... 

Lifetime extension would be a necessary preventive action to halt micro cracks expansion on the airplane external surface. To decide about whether to perform this operation, one should examine technological maturity, costs and technical parameters. Technical status in lifetime extension is one of the major drivers of this decision which should be considered in the first step of technology management process which is known as the technology attractiveness step. In this research, major technologies of rejuvenation is examined and categorized by the technology mapping. Also, key processes of rejuvenation and technological fields ranking has been determined by the procedural view tools of the... 

Currently, the relatively long time of the turbine life passes and their parts and equipment damage are different, that loss optimum performance and thus reducing their efficiency and may lead to faults and other unexpected stops in their production cycle. Process used to estimate the remaining life of the various components of this turbine is an important tool for improving the efficiency of these units to perform preventive maintenance. In the present thesis, the types of damages in different parts of gas turbines and various methods for detection of critical points, particularly finite element method, high cycle fatigue, modal analysis, methods to estimate the lifetime of a gas turbine... 

One of the main problems in the airline industry is that many aircrafts of today's fleet are approaching their calendaring life, and it is impossible to buy new planes and supply previous ones for most of the companies. Therefore, in order to extend the life of these aged planes, some studies have been performed. The purpose of these studies is to discover the causes of aging and removing them. Repairing, replacement and reinforcing some elements of the structure are important parts of this procedure. This process is called aging. One of the requirements of aging technology is the examination of the structural response to the applied external loads and knowledge of the structural design.... 

As aircraft fleets get older, the challenge of Flight Safety gets greater. This Thesis focus on management strategies and principles to keep long-life fleet safe and effective into old age. But the safety and efficacy are not the only ones who are considered at long-life fleet. Here the question arises why the aircraft prior to exposure to the effects of rising life expectancy, are not replaced by other aircraft.The reason is the high cost of the replacement. Aircraft are expensive to design and manufacture. In commercial aviation, extreme competition and miniscule profit force pressures to delay replacement of older aircraft with expensive new types. But in Military aircraft reason for... 

Our country in no measure is considered as an industrial one, despite its chain of small, medium and large industries. The vague, general “developing” term might be the best term to assign to economic-industrial condition of our country. We have a fairly limited number of big industrial firms (BIF) which could continue operation without state’s supports in a world BIFs are considered as the key indices in industrial development. The question comes to mind with reading what came above is this study’s main question, “What went wrong?”. This study follows the historical approach to the question through a comprehensive case study. Historical case-study thus is our main research approach here.... 

This study aims to examine cigarette consumption behavior of younger cohorts in the urban areas of Iran. we use Iranian household's income and expenditures survey over 2007-2012 and a double-hurdle modeling approach to take into account the zero expenditure on cigarette consumption. after controlling for price and demographic factors which determine the demand for cigarettes, we find that the younger cohorts tend to use more cigarettes than the older ones, however the age effects for men aged between 21-45 are positive  

Iran have experienced tangible demographic changes over the recent decades. Fertility rate and marriage rate have declined, but divorce rate has increased remarkably. This research intends to examine the propensity to marry and marriage age in Iran by use of Household expenditure and income survey data (2009-2012) in the framework of search and match model. In the underlying literature, some socioeconomic factors are identified as the main determinants of these changes, particularly labor market prospects and male’s earning structure are considered as the most significant factors among others.The data are pooled and for the study years are merged with cohort data from the labor market to... 

Average of females’ age in the first marriage was increasing in Iran, in the last two decade from 20.9 in 1991 To 22.7 in 2010. It is well accepted that labor market condition and the males’ wage structure are the main determinants of preference toward marriage among others. Making use of a provinces-wide panel data 1991 To 2010 and micro individualized data (Household income and expenditure survey) for all the provinces, this research aims to assess the role of males’ wage inequality in the marriage rate in provinces and the probit cross-section models of preferences toward marriage in Iran. In the frame work of search and match theory of marriage our findings reveal that wage inequality... 

The most common form of communication on the internet and social network websites is text messages. normally communication on social media or even on the web is by posting some sort of text. usually, these messages or posts are short and text used in them may not follow any language standards, this makes it very difficult to process them. Different age groups use a certain language differently and this is shown in the way, each of them writes texts. The advancements made in the field of natural language processing and computational linguistics makes it possible to predict, text authors age groups by analyzing the way they write. This study focuses on ways to automatically recognize the age... 

Due to reduced Non-Recurring Engineering (NRE) costs, shorter time to market, design flexibility, and reprogramming capability of Field-Programmable Gate Arrays (FPGAs) as compared to Application-Specific Integrated Circuits (ASICs), FPGAs has been raised as a suitable substrate for implementation of digital systems. However, the high flexibility of reconfigurable devices leads to great power consumption, chip area, and reliability difference between ASICs and FPGAs. In addition, with the advent of multi-tenant FPGAs in cloud computing environments, it has been shown that crosstalk side-channel attack, which can be used by a malicious IP to leak valuable information, has become an urgent... 

High reliability and low power consumption are two crucial requirements of embedded systems. To do this, embedded systems exploit fault-tolerant techniques to keep reliability at a guaranteed level and power management methods to reduce power consumption. However, the inherent redundancy of the fault-tolerant techniques increases the power consumption and, consequently, the system temperature, which leads to an increase in the rate of the aging phenomenon. Power management methods increase the system's lifetime by reducing the system temperature. However, some power management methods (e.g., Dynamic Voltage and Frequency Scaling) increase the fault rate. Recently, heterogeneous multicore... 

Shrinking the dimensions of transistors in recent fabrication technologies has led to an increase in the aging rate of chips, as the most important challenge in reliability of new processors. Bias Temperature Instability (BTI) and Hot Carrier Injection (HCI) are amongst the most important adverse effect of transistor shrinkage. These two effects decrease the switching speed of transistors by increasing its threshold voltage over time. Threshold voltage shift causes timing violation in combinational parts of circuit and decreases the robustness of sequential parts against soft errors. Between different units of a processor, Arithmetic and Logic Unit (ALU) is one of the most susceptible units... 

Despite the advantages of shrinking transistors’ dimensions, e.g. decrease in power consumption and fabrication cost and increase in their switching speed, it has an adverse impact on some characteristics of nano-scale (less than 130nm) transistors that can reduce the system lifetime. Bias Temperature Instability (BTI) and Hot Carrier Injection (HCI) are amongst the most important adverse effects of transistor shrinkage. These two effects, are known as transistor aging, decrease the switching speed of the transistors by increasing the threshold voltage and decreasing the charge carriers’ mobility in the channel of transistors. Temperature, operating voltage, and the size of transistors have... 

Reducing the size of transistors has dramatically increased the impacts of NBTI, HCI, and EM phenomena in comparison with decade ago. These phenomena are able to have influence on properties of different parts of a chip to make it changed gradually; including threshold voltage of a transistor and electrical conductivity of interconnections. These changes are known as the aging of a transistors that diminish the performance and reliability of a chip. A common reason that plays a significant role in all these phenomena is temperature. The temperature becomes more important when the power density increases per unit area due to decreased size of transistors, which is a trend in multi-core... 

Today's latest technology integrated circuits are manufactured for a wide range of applications. With the constant increase in the usage rate of integrated circuits, designing a high reliable system is of utmost importance. The avoidance of counterfeit components is a major challenge of hardware security and trust. Counterfeit components cause lower performance and reduced life span. They are of great concern to the manufacturers and consumers of electronic systems, impacting the security and reliability of these systems. If these parts end up in critical applications like medical systems, satellites, aerospace, or power plants, the results could be catastrophic. So far, there are different... 

Signifcant downscaling of CMOS technology to provide high performance along with low power consumption has been accompanied by reliability degradations such as increased noise sensitivity and reliability concern due to aging phenomena (transient and permanent failuers). In this regard, with huge number of configuration bits, Field-Programmable Gate Arrays (FPGAs) are more susceptible to aging since aging not only degrades the performance, but also it may additionally result in corrupting the configuration cells and thus causing permanent circuit malfunctioning. While several works have investigated the aging effects in Look-Up Tables (LUTs), the routing fabric of these devices is seldom...