Sharif Digital Repository

Congestive heart Failure (CHF) which occurs when the heart is no longer able to pump the blood sufficiently is a worldwide growing health concern. In the U.S. alone, an estimated 8 million people will be diagnosed with heart failure by 2030.Cardiac transplantation with limitations in donor availability, cannot solely resolve this global health concern. Therefore many patients must use alternative remedies, namely Artificial Heart and Ventricle Assist Device (VAD). The Left Ventricular Assist Device (LVAD) is a mechanical pump that is implanted in patients with congestive heart failure to help the left ventricle in pumping blood to the circulatory system. They are known to... 

Learning disability (LD) is a neurological condition that interferes with an individual’s ability to store, process, or produce information. There are different types of learning disabilities affecting reading, writing, speaking, spelling, etc. Based on a study conducted by National Center for Learning Disabilities, 2.4 million American public school students are diagnosed with learning disability. They attend school in order to learn and be successful while they do not know their learning process is different from their peers. LD diagnosis in children is especially important as such cases must be identified early enough in order to provide them with proper education.This project targets LD... 

Robust detection of human eye has attracted interest during the past decade. Certain research studies have focused on the capability of determining the location of the human eyes while few have been focused on its tracking. The main task in this study is not only a system with eye detection capability but also a robust and non-intrusive eye tracker system of the eye movement using the iris as a trace element within the image captured through the camera. Such utilization is particularly applicable in diagnosing of certain abnormalities such as Autism which result in distinct abnormal movement and behavior in the eyes. Proposed eye tracker algorithm was implemented using the Kalman filter. The... 

Triple Module redundancy (TMR) is a commonly used approach to increase reliability in space applications. Applying this method, triple modules and voting circuits are implemented in a field programmable gate array (FPGA). In TMR systems when a single event upset (SEU) occurs, the voting circuit neglects the failure value of a module receiving the SEU and takes a correct value from the other two modules. The present TMR approach utilized for the combinational and sequential logic on the gate level shows that it is possible to write hardware description language (VHDL) code in a structured yet high level coding style to obtain the required redundancy. However using VHDL, the level of required... 

Gesture and motion evaluation are needed for a variety of applications. The use of human hand motions as a natural interface tool has motivated researchers to conduct research in the modeling, analysis and evaluation of various hand movements. In particular, human-computer intelligent interaction has been a focus of research in vision-based gesture recognition. In this work, we introduce a 3-D hand model evaluation method that offers flexible and elaborate representation of hand motion. We used landmarked points on tips and joints of the fingers and calculated the 3-D coordinates of these points through a stereo vision system followed by an HMM (Hidden Markov Model) to recognize hand... 

Control of parallel robots continues to be a challenging research topic. The structural variety of such robots dictated by the application and function makes such control strategies even more unique. As these robots often require nonlinear control schemes, such research has been focused towards two general controlling computational intelligent methods, namely adaptive (and optimal) control and artificial intelligence (e.g. fuzzy and Neural Net) based control. This study considers Neural Net (NNs) and fuzzy control method in order to propose a control scheme for a newly introduced 5-link parallel robot which has 3 degrees of freedom operating in a single plane environment (i.e. two... 

Conventional MRI has been used to diagnose different types of brain injuries. However these methods have generally failed to diagnose mild types of injury. We are working on the specification of mild traumatic brain injury, using diffusion MRI data, based on a multi compartment simulation of white matter tissue. This effort is essential for better understanding of underlying tissue micro-structure changes in patients with trauma. Some studies have been used in similar data fitting approaches in order to estimate axon diameter distribution. Specifically, a comparative study between different Compartment Models has shown that “ActiveAx” model has the best agreement with underlying tissue... 

With advancements in control and robotics technology, wearable robots have gained multiple applications in rehabilitation and power augmentation. In robots developed for power augmentation purposes, human decisions are combined with robot power to enhance the human ability to perform various activities, such as carrying heavy loads and walking for a long time. In cases where robots are designed to help humans to carry heavy loads, the robot control strategy should minimize the human-robot interaction forces. In this case, heavy loads influence the robot and the user no longer need to use more energy than normal walking, and the robot works following human intentions. Where the robot works to... 

Tinnitus means hearing a sound without an external source. Despite the research done in relation to it, it is still an unknown phenomenon and no method has been introduced to treat it. Repetitive transcranial magnetic stimulation is one of the methods that its effectiveness in decreasing tinnitus sound is still under investigation. This technology is a non-invasive method to stimulate the brain, which modulates the activity of neurons by applying successive electromagnetic pulses on the scalp. Most of the studies conducted in this field have used clinical evaluations to investigate the effect of stimulation. Relying on this method alone to evaluate the effect of stimulation cannot take a... 

Tinnitus is variety of sounds heard when no corresponding external sound is present. To remedy this condition, various methods have been proposed, however none have resulted in systematic and lasting results. This study aims to investigate the efficacy of non-invasive electrical stimulation techniques (tES) in the treatment of tinnitus. Stimulation parameters, including intensity, frequency, duration, and session frequency, are tailored to the individual's subjective tinnitus characteristics and treatment goals. Specifically, transcranial direct current stimulation (tDCS) is explored as a non-invasive method of electrical stimulation. In the tDCS method, electrodes are strategically... 

Medical ultrasound imaging is one of the common imaging methods in modern medicine, which is used to diagnose and even treat some diseases due to its cheapness and harmlessness. Medical ultrasound transducer arrays have a significant error rate. They are a major cause of failure in ultrasound imaging systems. This problem causes a noticeable decrease in the quality of the images and medical misdiagnoses. The topics of accurate detection of the location and severity of the error or failure, as well as the compensation for weak transducers by signal processing methods, have received less attention from predecessor researchers. In this thesis, an innovative method for accurate error detection... 

Subcutaneous needle insertion is one of the key methods of limited invasive surgery in medical diagnosis and treatment. However, errors in needle targeting can reduce the effectiveness of such efforts. One of the main factors of errors is due to the human guidance of the needle, which many researches have approached in recent years, and among the suggested solutions is the use of automatic or semi-automatic assist systems. Considering the treatment of prostate cancer by brachytherapy method, this research has developed a semi-automatic physician assistance system using navigation based on the potential field method and ultrasound images of the needle location, and sliding mode fuzzy... 

Humans, as a diploid species, have two nucleotide sequences of homologous chromosomes in their genomes, where one set is inherited from the mother, and the other comes from the father. The Single Individual Haplotype assembly problem (SIH) refers to the reconstruction of these two distinct nucleotide sequences of a chromosome from the sequencing reads, and it is currently considered one of the most important issues in the field of computational genomics, which plays an essential role in solving various genetic and medical problems.Nowadays direct experimental methods are not welcomed due to their high cost, and labor intensity, and are limited to certain regions of the genome, therefore,... 

The quantity and quality of information extracted from the brain, in addition to data collection methods, is also related to the statistical tools used. As extracting maximum information in both temporal and spatial dimension require electrophysiological approaches on the physical side, the statistical methods should be optimized to that end, on the theoretical side. The time histogram method is the most basic tool for capturing a time-dependent rate of neuronal spikes. Generally, in the neurophysiological literature, the bin size that critically determines the goodness of the fit of the time histogram to the underlying spike rate has been subjectively selected by individual researchers.... 

Wireless area body networks (WBANs) are a set of sensors designed to monitor an individual’s health remotely. These networks are required to transfer the data properly to the healthcare professional. Since there is no guarantee that no faults might occur, these networks should have fault tolerance capability such that they can maintain their main function properly. In this thesis, a method for fault tolerance in WBANs is proposed.In this research, to test the proposed method, a case study on sleep apnea disorder is selected for monitoring patients who experience sleep apnea. To this end, the Apnea-ECG dataset from the PhysioNet repository was considered which contains five different types of... 

Identifying and interpreting standard fetal plates in first trimester examinations with two-dimensional ultrasound is a very complex task that requires years of experience. Aside from the challenge to position and direct the probe to required positions, there is an understandable difficultly for inexperienced sonologists to identify the corresponding structures in the emerging images. Automated image processing can be helpful both to the experienced as well as inexperienced operators to confront these challenges. In this study, we used data from three different devices SAMSUNG WS80A, VOLUSON E6, VOLUSON E8, which includes a total of 2230 images to measure the thickness of the space behind... 

Ultrasound imaging is one of the most widely used diagnostic methods in medicine due to its safety, cost-effectiveness and small and portable size of equipment. In this imaging method, line-by-line scanning is used to create the image, which has limitations in speed and resolution. To deal with these limitations, new methods have been proposed, such as plane-wave imaging with the possibility of increasing the imaging speed and synthetic apertures with the possibility of increasing the quality of images. By combining these two methods, high quality and speed can be achieved simultaneously. Therefore, in this research, based on previous studies, a number of elements were activated each time,... 

Extensive studies have been performed on the genetic variations involved in common neurodegenerative diseases such as Alzheimer's, macular degeneration, and Parkinson's. In most cases, no specific gene has been identified pointing to a distinct pathogenic pathway, therefore, this study mainly aims to find common genes among aforementioned diseases according to determination of a specific pathogenic protein pathway.In this study, we reached a deep understanding of the function of nervous system and the discovery of causative agents of the diseases by applying the sources of information from genome datasets in bioinformatics analysis. The utilized database comprises the classification of... 

According to clinical surveys, it is estimated that chronic tinnitus is experienced by 10 to 15% of the adult population. Tinnitus is defined as the conscious and involuntary perception of noise or ringing without involvement of either mechanical or external audio source. In recent years, a limited number of studies have investigated the effects of applying transcranial magnetic stimulation (TMS) to ameliorate this condition. TMS is a noninvasive intervention in which magnetic pulses are applied by a coil adjacent to the individual's head. In this study, electroencephalogram (EEG) signals are recorded concurrent and as a follow-up to TMS. This makes it possible to study changes caused by... 

LFP characteristics have been shown to be informative of sensory stimuli and influenced by attention. We show the gamma power in area MT is selective to motion direction showing a Gaussian tuning curve. Here we show for the first time, some evidence based on a single monkey’s data that spatial attention enhances the tuning curve based on gamma power.The synchronization of activity across neurons has been a focus in many recent studies of information processing in networks of cortical cells and areas. One aspect of such inter-neuronal synchrony is the locking of spiking activity to local field potentials (LFPs). Such an interaction has been observed between the timing of individual action...