Sharif Digital Repository

According to epidemiological studies conducted in Iran, nowadays, about 200 to 300 people in Iran suffer from stroke. The hands, including fingers, are the most injured and cause one’s disability and creates many direct and indirect costs for the person and the government. In addition to stroke, injuries caused by the use of various apparatus are responsible for hands disruption. It is usually referred to a physiotherapist for the physical disabilities treatment, the treatment process is quite long and time-consuming (usually a one-year physiotherapy). After this treatment, the physiotherapist will prescribe exercise and radiation therapies for the patient. Therefore, in recent years the... 

Increasing demand of bandwidth in wireless communications systems led to excessive congestion in frequency spectrum. Since radio spectrum is an expensive and rare source, its efcient use is an important challenge. These limitations as well as increasing number of communications service users,necessitate the use of newer technologies that work efciently with numerous users. Device-to-Device (D2D) communications, full-duplex capability and cognitive radio systems are introduced for this reason. In the previous technologies, due to excessive self-interference (SI), full-duplex transmission has not been implemented. However nowadays technology allows self-interference to be attenuated up to 100... 

Co-culture of different cells is necessary for cancer spheroid formation in preclinical drug tests. It is possible to produce thousands of micro-droplets containing different cells, i.e. microcapsules, in a short time, using droplet microfluidics. However the homogeneity of the cell numbers in the droplets has remained as an unsolved problem.Despite the large amount of experimental efforts to reduce the number of undesirable microcapsules, no one tried to utilize the ease of computer aided simulation for investigating different parameters. In this study, we develop a novel method for capturing cell encapsulation using CFD simulations. The effect of the cell suspension inhomogeneity and... 

A Lab-On-a-Chip (LOC) is a device which can integrate one or many laboratory functions on a small chip with millimeters to few square centimeters in size. LOC is a subset of MEMS devices and known as “Micro Total Analysis Systems” (µTAS) as well. LOC technology is closely related to microfluidics which primarily describes the physics, manipulation and study of minute amount of fluids.In this research we tried to simulate the performance of a microfluidic device for counting blood cells to find main factors of it for design and manufacturing. This research has two main sections, hydrodynamics of fluid inside the microchannels and finding electrical performance of designed Coulter counter for... 

Execution speed seriously bothers application developers and users for wearable devices such as Google Glass. Intensive applications like Mobile Augmented Reality (MAR) suffer from significant delays when CPU is busy. Energy is another concern when the devices are in low battery level but users need them for urgency use. To ease such pains, one approach is to expand the computational power by cloud offloading. This paradigm works well when the available Internet access has enough bandwidth. Another way, however, is to leverage nearby devices for computation offloading, which is known as device-to-device (D2D) offloading. In this paper, we present Dandelion, a unified code offloading system... 

Renal diseases and consequently kidney failure is one of the important death factors around the world in recent years. It causes hundreds of thousands die every year and is in progress. Researchers believe that increasing chemical and nonchemical materials density in the blood which is the air pollution, use of tobacco and other parameters cause renal cells misfunction in urine filtration and regulation of blood pressure. The goal of this work is design and fabrication of a microfluidic device which provides different cell types to be cultured and imposed pressure. To do this, a high throughput microfluidic device is needed to mimic kidney biologically. Having such a device helps to analyze... 

Characterization of local magnetic activity of the heart muscles is named magnetocardiography (MCG), which measures magnetic field generated by electrical activity around heart. RF SQUID sensors are appropriate choice for measuring magnetic activity of the heart muscles. Because squid detects weak signals as low as fTesla, while heart magnetic field is near 50 pt which is one millionth of earth magnetic field and thousands of time weaker than the environment noise. One of the problems of mcg system is its urgency to shielding of unwanted magnetic field. In this project design of holders and resonators for well coupled input coil with RF SQUID is improved. As a result, at the first stage... 

Memories today expose an all-or-nothing correctness model thatincurs significant costs in performance, energy, area, and designcomplexity. But not all applications need high-precision storagefor all of their data structures all of the time. This these proposesmechan-isms that enable applications to store data approximately in a phase change memory main memoryand shows that doing so can improve the performance and reduce the power consumption by proposing two mechanisms. The First allows errors in multi-level cells by reducing the number ofprogramming pulses used to write them. The second mechanism reduces the number of error-prone patterns in the content of data block through a lightweith... 

The increase in mobile data traffic adversely affects the quality of service experienced by mobile users. Moreover, the cost incurred by developing infrastructure exceeds its profit. Therefore, there is a trend toward finding cost effective schemes to cope with increase in mobile data traffic. One of the recent elegant solutions is mobile data offloading based on D2D communications. In this thesis, we propose a new offloading scheme using D2D communications for delay-tolerant services. In this regard, we assume a common file is demanded by a subset of users in different time instances and we accumulate demands to serve them in a scheme where devices are divided into non-overlapping... 

Nowadays, electrical energy is a necessity and the use of intelligent power equipment is expanding. Of course, having a protocol for communicating between such equipment is not only useful but sometimes mandatory. In the past, each equipment manufacturer used its own method for communication, hence, the "IEC 61850" standard was proposed as a solution to solve the problem of communication between different equipment. In this research, we intend to design a tester to perform a performance test with for GOOSE messages. These messages are based on the IEC 61850 data set and have the ability to quickly and securely distribute input and output values at the system level, which are transmitted by a... 

This thesis activities, consists of three main parts. The first part is, manufacturing and optimization of the electrical part of blood glucose measurement devices, based on electrochemical sensors. In this part, design of blood glucose measurement systems based on two and three electrode electrochemical sensors are proceeded and the accuracy of the electrical block, is increased up to 1mg/dl according to sensor current range. The second part, is related to the design of different probes for blood electrical characteristics (impedance magnitude) measurements, at low frequencies. Measurements with these probes show, first the blood impedance magnitude range at low frequencies and moreover,... 

Automatic Speech Recognition (ASR) systems are a significant part of Personal Assistants in mobile phones. But because of the time-dependent nature of ASR systems, they are computation and memory-intensive tasks. On the other hand, mobile devices utilize a Low-Power design to extend battery life and improve user experience, making them incompatible with heavy-loaded tasks such as ASR systems. For instance, if we run an inference with a 60 seconds audio file on a well-known open-sourced Speech Recognition System named DeepSpeech, it will only take 49 seconds for a desktop PC to generate the results. Still, a mobile phone with ARM64 architecture with the same input file will take 92 seconds to... 

Graphene -a two-dimensional monolayer of graphite- was realized for the first time in 2004.Owing to its physical extra ordinary properties, graphene has attracted growing interest in research from fundamental physics to electronics, spintronics, and thermoelectrics. Importantly, it is an attractive material for electronics and spintronics due to its specific physical properties such as high electron mobility and gate tunable carrier concentration. Furthermore,achievement of room-temperature spin transport with relatively long spin relaxation time makes graphene nanoribbons the best candidate for spintronics. Based on the theoretical predictions, the weak spin-orbit interaction in graphene... 

Depletion of the fossil fuel resources along with the environmental concerns have led to a significant growth in utilization of Renewable Energy Resources (RERs). Among different kinds of RERs, wind energy due to maturity of its associated conversion technologies and also its widespread presence in different regions has experienced a more rapid usage in generation sector of power systems. Despite numerous benefits of this environmentally-friendly energy, uncontrollability and uncertainty in output power of wind turbines has resulted in many technical issues for operators of power systems. However, it has been shown that the presence of various storage system technologies can alleviate these... 

The expansion of technology and the increasing use of mobile devices and smartphones have aected various aspects of personal and social life. These include the use of personal mobile devices in enterprise environments called BYODs have a number of positive and negative eects. On the one hand, it would be more cost-eective for an organization or business environment for users to use their own devices, but on the other hand, it poses numerous security and information challenges that are important to manage. These include disrupting the user’s privacy or disseminating organization information to personal devices and thus violating the organization’s security policies. In this study, a model is... 

Nowadays, separation and filtration of particles has many industrial applications in biology and medicine. In this thesis, passive microfluidics are designed and simulated which are able to separate and filter particles. Although particles aer generally expected to follow laminar flow streamlines in the absence of external forces, inertial forxes van cause particles to migrate across mictochannels in an accurate and predictable manner. The effect of these forces is invedtigated, and by using previous research, a model is developed to predict these forces. First design is a microchannel with Archimedean spiral which utilizes both inertial forces and Dean flow to separate particles in the... 

In this research, the surface of cellulose paper was modified with Hexadecyltrimethoxysilane, Phenyltriethoxysilane, (3-Aminopropyl)triethoxysilane and 3-(2,3-epoxypropoxy)propyltrimethoxysilane via chemical bonding. Afterwards, the prepared papers were placed in the microfluidic device as sorbent in a sandwiched format. A syringe pump was used to drive the sample into the microfluidic channel. In order to investigated the performance of these sorbents, two types of anlaytes including toxins and antidepressant drugs were chosen as target analytes. In the case of toxins, ethion, fenthion, profenfose, diazinon, atrazine and ametryn were studied. among the antidepressant drugs,... 

The increasing gap between performance of Hard Disk Drives (HDDs) and processors has made storage subsystem as the performance bottleneck of computer systems. Solid-State Drives (SSDs) due to having no mechanical parts provide higher performance compared to HDDs. However, the high price of SSDs compared to HDDs prevents them from replacing HDDs. Employing SSDs as a caching layer for HDDs is a cost-efficient solution for designing high-performance storage subsystems. Previous studies on SSD caching neglected to simultaneously consider performance, endurance, and reliability in their architectures. In this thesis, Three-level I/O Cache Architecture (TICA) is proposed, which tries to improve... 

Nowadays, cancer, which has been mentioned as the disease of the century, is the second leading cause of death throughout the world, and its incidence is constantly increasing. Isolation of circulating tumor cells is one of the most critical steps in diagnosing and controlling cancer progression. Due to the rarity of cancer cells compared to other cells in the blood sample, the isolation process requires optimal and high-precision devices. With the advent of inertial microfluidics, the ability to control the particles movement, the processing of blood samples as quickly and accurately as possible, and the viability of cells with a high percentage, introduced microfluidic systems as a... 

Exoskeleton is a newborn technology for disabled people. Personal exoskeleton is a type that is suitable for replacement of wheelchair. Exoped, the first Iranian exoskeleton made by Pedasys company, was a rehabilitation one. The purpose of this research was enhancing the design of its actuators to accomplish lighter, smaller and cheaper one. At first we identified the different loads that are applied to actuators of exoskeleton and we tried to decrease the number of actuators needed, as more as possible. Then we modeled the exoskeleton-user system to measure the required parameters. Using this model, we conducted an algorithm to design appropriate gait cycle for walking with the help of...