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Chaos Control Using Markov Models based on Takens Embedding Theory
, M.Sc. Thesis Sharif University of Technology ; Salarieh, Hassan (Supervisor)
Abstract
Chaos theory examines complex systems whose output results in large changes by applying small changes to the initial conditions. In other words, some seemingly accidental phenomena for which we have not yet found a reason can be justified with the help of chaos theory. The strong dependence of the response to the initial conditions is one of the most important features of turbulent systems, but their quasi-random behavior will be independent of these conditions after some time. Chaotic systems, as an important branch of nonlinear dynamic systems, behave close to stochastic systems. Perhaps the most important similarity between the two systems is the existence of invariant probability density...
Application of Data Mining Techniques in Diagnosis & Prediction of Heart Disease
, M.Sc. Thesis Sharif University of Technology ; Akhavan Niaki, Taghi (Supervisor)
Abstract
Nowadays, data is the most important asset for health organizations in which the process of collecting, storing and analyzing of data leads to success of health organizations. Many companies have turned to data mining for the beneficial use of these data. The main purpose of data mining is to obtain useful knowledge from existing data. One of the diseases that is very significant for data miners is cardiovascular disease. Cardiovascular disease is the most important cause of death in the world. Therefore, it is necessary to improve the diagnostic and predictive measures of these patients. In this study, a database containing of characteristics of patients with chest pain who referred to...
Prediction of Heart Arrhythmias Related to Pramature Beats
, M.Sc. Thesis Sharif University of Technology ; Shamsollahi, Mohammad Bagher (Supervisor)
Abstract
About 42 percent of annual mortality in all around the world is originated from cardiovascular arrhythmias and diseases. One of these arrhythmias is atrial fibrillation whose onset and persistence can produce clot and consequently cause stroke. The basis of our research are upon this idea that dangerous heart arrhythmias do not happen abruptly and there always are some background signs before occurrence of them. In our approach to predict the onset of atrial fibrillation, by analyzing ECG signal in order to extract distinguishing features, we want to classify signals which will terminate Paroxysmal Atrial Fibrillation (PAF) from signals which won’t end with PAF. In this thesis, we propose...
Prediction Using Data Mining Techniques in Healthcare
, M.Sc. Thesis Sharif University of Technology ; Akhavan Niaki, Taghi (Supervisor)
Abstract
Poor decision making in health care has always had irreparable consequences for society. Also, expensive medical tests cause lots of problems for patients. A huge amount of data is produced daily by hospitals, which unfortunately are not used to improve decision making and predicting disease. Data mining can be an appropriate tool for extracting knowledge from a huge amount of data by using a variety of techniques such as prediction. The leading cause of death in the world is heart disease so this study has been designed to predict the incidence of that. Regarding the literature review, the Naïve Bayes method had predicted heart disease accurately. According to the specialist's opinion, some...
Modeling and Intelligent Control of Heart Assist Device
, M.Sc. Thesis Sharif University of Technology ; Jahed, Mehran (Supervisor)
Abstract
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...
Modeling of Different Geometries of Children's Heart Occluder's by Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Arghavani, Jamal (Supervisor)
Abstract
Congenital heart defects are a type of heart diseases that some babies get at birth. These diseases generally have symptoms such as shortness of breath, headache, impaired blood supply, hyperplasia of the lungs, enlarged heart, and so on. In the past, open heart surgery was commonly used to treat such diseases, which was a costly and risky procedure. But over time, occluders made it easier. An occluder is referd to a device that is generally minimally invasive in the area of the fault and could block it. The occluders are usually braided type, with inside polyethylene fibers, where tissues can grow and clogs the defect over time. Although occluders have greatly increased the success rate of...
2-D Modeling of Blood Flow in Mitral Valve During its Closing and Opening
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Saeedi, Mohammad Saeed (Co-Supervisor)
Abstract
Problems with the mitral valve can make the heart less efficient at pumping blood around the body. Severe problems can lead to heart failure if the valve is not surgically repaired or replaced. A simple approximation of the heart geometry is used and the valve dimensions are based on reported measurements. The primary objective for this study is to design and simulate the opening and closing behavior of the mitral valve using 2D fluid-structure interaction (FSI) model using ADINA software in order to evaluate and investigate the hemodynamic performance and problems of mitral valve, in which the blood is described as a viscous incompressible fluid, and the mitral valve is described as an...
Modeling Propagation of Cardiac Action Potential at Cellular Level
, M.Sc. Thesis Sharif University of Technology ; Jahed, Mehran (Supervisor)
Abstract
Heartbeat is the result of contractions of over 10 billion cardiac cells. These cells’ cytoplasms are connected to each other by gap junctions which are arrays of intercellular protein channels. Thus action potential can propagate from one cell to another and cause its contraction. In core-conductor model, one-dimensional microscopic representation of cardiac tissue, cells are attached to each other to form a ladder network. The parallel elements are connected to each other by series resistors which represent gap junctions. These resistors are nearly always considered as static elements. In this thesis I have investigated the effects of incorporating the dynamicity of gap junction resistors...
Modeling the Relationship between Central Aortic Pressure and Radial Photoplethysmogram in Flow-mediated Dilation Test
, Ph.D. Dissertation Sharif University of Technology ; Vosughi Vahdat, Bijan (Supervisor) ; Zahedi, Edmond (Supervisor)
Abstract
According to the World Health Organization, about 35% of deaths worldwide are due to cardiovascular diseases, therefore the evaluation of vascular endothelial function has great prognostic and diagnostic value for cardiovascular diseases. The conventional noninvasive method for endothelial function evaluation is the measurement of flow-mediated dilation in brachial artery using ultrasound imaging (FMD-US). As the accuracy of FMD-US depends on the operator's skill and the resolution of the ultrasound images, this method has not been adopted. In this work, we propose to use a low cost, easily-accessible surrogate signal, the photoplethysmogram (PPG) to implement the FMD test. Whereas previous...
Expansion Modeling of Coronary Stent for Selection of Optimized Stent
,
M.Sc. Thesis
Sharif University of Technology
;
Movahhedy, Mohammad Reza
(Supervisor)
Abstract
Referring to mortality increasment having sprung from atherosclerosis, work on treatment of coronary heart disease seems to be necessary. Stent implementation is one of stenosis treatment. Stent deployment has been done during past two decades, but clinical evidence showed that because of some weakness in designing and implementing, restenosis occurs again. Material, structure and coating texture of stent are the designing criteria beside stent implementation importance. Thus a lot of activities have been done in this area to improve performance of these applications. Nowadays a lot of companies' researchers try the best to get better their products; consequently there is different types of...
The Design of Ventricular Assist Devices and Analysis of Blood Flow Within them
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor) ; Afshin, Hossein (Supervisor)
Abstract
Heart is a muscular organ, which pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste to the lungs. Heart is sort of like a pump, or two pumps in one. The right side of heart receives blood from the body and pumps it to the lungs. The left side of the heart does the exact opposite: It receives blood from the lungs and pumps it out to the body. However, in end-stage heart failure, the heart can no longer pump enough blood to meet the body’s needs, in which case implantable left ventricular assist devices provide support for patients at risk of death from end-stage heart failure.Centrimag...
Design and Efficient Implementation of Deep Learning Algorithm for ECG Classification
, M.Sc. Thesis Sharif University of Technology ; Hashemi, Matin (Supervisor)
Abstract
Cardiovascular diseases are the leading cause of death globally so early diagnosis of them is important. Many researchers focused on this field. First signs of cardiac diseases appear in the electrocardiogram signal. This signal represents the electrical activity of the heart so it’s primarily used for the detection and classification of cardiac arrhythmias. Permanent monitoring of this signal is not possible for specialists so we should do this by means of Artificial Intelligence. In this thesis, we use recurrent neural networks to classify electrocardiogram’s arrhythmias. This deep learning method, use two sources of data to learn from. The first part of data is global for everyone and the...
Design and Efficient Implementation of ECG-based Detection Algorithm for Dangerous Myocardial Problems
, M.Sc. Thesis Sharif University of Technology ; Hashemi, Matin (Supervisor) ; Vosooghi Vahdat, Bizhan (Co-Advisor)
Abstract
Cardiovascular diseases are the first leading cause of death in the world also in IRAN. Early detection of such problems can decrease the costs also can help to cure the patient but it needs continuous monitoring and automated classification of hearbeats. Mobile devices and wearable gadgets are good solutions which can help patients before visiting the doctor.In this research, an algorithm is introduced which with the help of ECG signal detects dangerous myocardial problems. Our approach is using deep learning method which were not considered much before. In the proposed algorithm ECG signal is processed in order to get features and with dimensionality reduction, input of the network gets...
Design and Simulation of Bioimpedance Chip for Monitoring Heart Failure
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
Cardiovascular disease is one of the leading causes of death and mortality. among these diseases, heart muscle inability, especially acute decompensated heart failure is very common. There are several methods to diagnose and monitor this disease, but a method that is accurate, non-invasive, portable and easy to access and easy to measure without multiple visits to the clinic; Priority for use. Early detection and continuous monitoring of fluid status by measuring the bio-impedance (Bio-Z) measurement of thoracic magnitude or phase is critical in reducing the mortality of chronic heart failure (CHF) patients. In this dissertation, for monitoring chronic heart failure, bio-impedance chips with...
Design and Manufacturing of Left Ventricular Assist Device for Patients Undergoing Cardiac Surgery
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor) ; Firouzbakhsh, Keikhosrow (Supervisor)
Abstract
The heart is a powerful muscle whose primary function is to pump blood into the body. many cardiac patients reach a stage that can no longer be kept function of their heart to a satisfactory level by using medication thus doctors undergo surgery. The common problem occurs to most patients undergoing cardiac surgery is that after the surgery, the patient's heart during a short period of time is unable to supply blood with the flow rate and pressure required for all organs, especially the end organs of the body. In this conditions, ventricular assist device help the patients. These devices are used parallel with patient’s heart and supply the large portion of blood that patient’s body needs....
Designing and Manufacturing of an Electrospinning Machine and Prediction of Mechanical Responses of Artificial Blood Vessels Using Neural Networks and Finite Element Analysis
, M.Sc. Thesis Sharif University of Technology ; Nourani, Amir (Supervisor) ; Chizari, Mahmoud (Co-Supervisor)
Abstract
Cardiovascular disease is one of the most leading causes of death in the world and one of the common methods for treating such diseases is replacing damaged blood vessels with artificial ones. Electrospinning, which is a method of producing polymer fibers, is one of the best and common methods of producing synthetic vessels. The first goal in this study was to create a suitable structure for fiber production; therefore, first, an electrospinning device and environmental chamber were designed and built. Then, the effect of alternative and uniform flow on the diameter and structure of the fibers was investigated using 15% wt. Polycaprolactone solution. The results of this study showed that the...
Design and Implementation of Wearable Device for Stress Level Measurement
, M.Sc. Thesis Sharif University of Technology ; Fakharzadeh, Mohammad (Supervisor)
Abstract
An inseparable problem from human daily life is stress that causes problems such as heart disease and depression, so stress management and control is essential for the health of the individual and society. This thesis explores the possibility of stress detection using vital signs and machine learning algorithms. First, by examining the potential of unsupervised learning algorithms for stress detection, a general method is developed and the accuracy of the algorithm is evaluated with the ECG signals of a smart wristband made in Sharif University of Technology Biosen group as well as WESAD data set. The self-organizing map structure is created based on stress-related features and final result...
Design an Analysis of a Heartbeat Motion Compensation Controller in a Robotic Coronary Artery Bypass Graft Surgery
, M.Sc. Thesis Sharif University of Technology ; Behzadipour, Saeed (Supervisor)
Abstract
The Coronary artery bypass grafting surgery is one of the most complicated and invasive surgeries, in which the chest is cleaved up to 20 cm. Also, heart motion with 1-2Hz frequency bothers surgeons to perform on. This leads surgeons to get interested in minimally invasive robotic surgery methods. The idea is to synchronize the robot motion with heart, in order for surgeons to perceive it stationary. This needs 3 major stages: online taking of data, estimate the future heart motion, and control the robot. First studies employ visual seroving for control demand. Later studies, although differ in data collection methods, rely on classic error-based feedback controllers, such as PID. Fast...
Design and Optimization of Channeled Hydrogel Scaffold Based on Extracellular Matrix of Heart Tissue with Oxygen Release Capability
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohreh (Supervisor) ; Khorshidi, Sajedeh (Co-Supervisor)
Abstract
Despite the increase in the number of cardiovascular diseases worldwide, the number of new drugs to treat these diseases has been decreasing in the last decade. Current preclinical drug evaluation strategies, which use cell cultures and oversimplified animal models, cannot meet the growing demand for new and effective drugs. In the last decade, the development of microfluidic bioreactors and organ-on-chip systems to improve the drug screening process has been increasing significantly. These systems have shown many advantages over previous preclinical models. Despite all these advantages, keeping the oxygen concentration at the optimal physiological level in microfluidic systems has its own...
Design of Amniotic Membrane-based Hydrogel for Cardiac Tissue Engineering Application
, M.Sc. Thesis Sharif University of Technology ; Yaghmaei, Sohila (Supervisor) ; Saadatmand, Maryam (Supervisor)
Abstract
Mammalian cardiac tissue lacks the ability to effectively self-regenerate following severe damage. The application of external therapeutic agents with strong mechanical properties is needed to restore its function. Even though conventional therapies have several challenges and limitations, injectable hydrogels, with minimally invasive, can significantly improve cardiac tissue regeneration. Extracellular matrices are the most appropriate biomaterials for synthesizing cardiac scaffolds. The human amniotic membrane obtained from the amniotic sac is a readily available, abundant, and inexpensive candidate that has been successfully utilized for the clinical treatment of cardiac diseases....