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    Fetal electrocardiogram modeling using hybrid evolutionary firefly algorithm and extreme learning machine

    , Article Multidimensional Systems and Signal Processing ; Volume 31, Issue 1 , 2020 , Pages 117-133 Akhavan Amjadi, M ; Sharif University of Technology
    Springer  2020
    Abstract
    Extraction of fetal electrocardiogram (FECG) from the abdominal region of the mother’s skin is challenge task due to the high overlapping of maternal and fetal signals in this area. To overcome the problem, this paper proposes the utilization of extreme learning model (ELM) as the prediction algorithm to train on the FECG signal extracted by least mean square approach from the input abdominal and thoracic signals. The trained ELM model is used to model the FECG signal for the testing samples. Also, this paper investigates the firefly algorithm (FA) to tune the parameters of ELM and improve its performance. Due to the high complexity and too many parameters of FA, this paper embeds the... 

    Fetal ECG Signal Extraction from Maternal Abdominal Recording Using Source Separation Methods

    , M.Sc. Thesis Sharif University of Technology Akhavan Amjadi, Majid (Author) ; Shamsollahi, Mohammad Bagher (Supervisor)
    Abstract
    Analysis of performance of fetal heart is very important for monitoring its health. In recent years a lot of research is performed on recording electronic signals from mother abdomen which consist of combination of maternal ECG and fetal ECG. Purpose of this thesis is investigating methods. For evaluation of different methods simulated ECG dataset and Dalsy dataset as real data were used. In this thesis Wavelet and EMD denoising as single channel methods and ICA, PiCA and deflation as multichannel methods are used. At last novel combinations of these methods is proposed which outperforms existing methods  

    Town Trip Analysis With Data Mining and Statistical Techniques

    , M.Sc. Thesis Sharif University of Technology Fili, Mohammad (Author) ; Khedmati, Majid (Supervisor) ; Akhavan Niaki, Taghi ($item.subfieldsMap.e)
    Abstract
    One of the most trivial factors for every service company is to fulfill customer demands and to satisfy them. For this purpose, it is needed to explore the business fundamentals. Transportation companies, however seem to be more important, because in one hand, the demand for their services is too many. In the other hand due to the intense competition between rivals, every business tries to stand in the crowd; thus, it is of high importance to correctly predict the travel time as well as fare. The importance of time is not only because of having a fare pricing system, but also it is important for scheduling, assigning drivers, and covering city or a particular district. Travel time... 

    Optimizing a Comprehensive Investment Portfolio Consisting of Different Asset Classes Using Machine Learning Algorithms

    , M.Sc. Thesis Sharif University of Technology Rahimi, Danial (Author) ; Akhavan Niaki, Taghi (Supervisor) ; Khedmati, Majid (Supervisor)
    Abstract
    Portfolio optimization in modern markets faces significant challenges stemming from the dynamic environment and the ever-increasing diversity of assets. Addressing the existing gaps in the literature, this research proposes an innovative framework based on Multi-Agent Deep Reinforcement Learning (MADRL) to manage a comprehensive and constrained investment portfolio. The proposed framework features a hierarchical architecture, decomposing the problem into two sub-problems: asset selection (by independent agents) and weight allocation (by a senior agent). By incorporating real-world market constraints and employing a risk-averse reward function based on the Conditional Value at Risk (CVaR)... 

    Optimizing Efficiency and Forecasting for Blood Bank Centers Using Advanced Deep Learning and Data Envelopment Analysis

    , M.Sc. Thesis Sharif University of Technology Hamisheh Bahar, Mahdi (Author) ; Akhavan Niaki, Taghi (Supervisor) ; Khedmati, Majid (Co-Supervisor)
    Abstract
    This research develops a multi-objective robust data envelopment analysis framework integrated with advanced deep learning techniques to forecast the future performance of decision-making units within blood supply chains. The model significantly advances traditional performance evaluation by incorporating a sophisticated temporal dimension, enabling the assessment of efficiency across multiple periods rather than at a single point in time. This dynamic approach leverages cutting-edge forecasting methodologies, including attention-based Long Short-Term Memory networks for modelling Generalised Autoregressive Conditional Heteroskedasticity parameters and Segmented Recurrent Neural Networks.... 

    Spatial mode control of a CO2 laser by use of controllable back mirror focal length

    , Article Review of Scientific Instruments ; Volume 73, Issue 1 , 2002 , Pages 225- ; 00346748 (ISSN) Amjadi, A ; Sharif University of Technology
    2002

    Using Data Mining in Customer Relationship Management (Case Study of the Insurance Industry)

    , M.Sc. Thesis Sharif University of Technology Khalilpour Darzi, Mohammad Rasoul (Author) ; Akhavan Niaki, Taghi (Supervisor) ; Khedmati, Majid (Co-Supervisor)
    Abstract
    This paper presents some approaches based on data mining techniques to solve the prediction task of Computational Intelligence and Learning (CoIL) Challenge 2000. The prediction task of the contest is a direct mailing problem and the goal is to improve its response rate. The main issue in this competition is the incompatibility of the dataset in which the distribution of the classes of the target attribute is highly unbalanced. This in turn causes high error rate in identifying the minority class samples. Three different level methods including data-level, algorithm-level, and hybrid method are used to overcome this issue. The specificity and sensitivity criteria are employed to compare the... 

    Numerical investigation of fast axial flow high power CW CO2 laser: Considering the effect of intensity variation

    , Article Scientia Iranica ; Volume 10, Issue 4 , 2003 , Pages 443-448 ; 10263098 (ISSN) Amjadi, A ; Imangholi, B ; Sharif University of Technology
    Sharif University of Technology  2003
    Abstract
    The effect of intensity variation on the quantum densities of active medium and thermodynamic characteristics of a high turbulent flow CO2 laser has been investigated. Comparison between the calculation of constant and variant intensity on the quantum densities and thermodynamic characteristics of turbulent gas flow shows a ∼ 10% drop in the output power of the laser, which is only 50 cm long. © Sharif University of Technology, October 2003  

    Thin Film Thickness Measurement Using Colors of Interference Fringes

    , M.Sc. Thesis Sharif University of Technology Sadegh, Sanaz (Author) ; Amjadi, Ahmad (Supervisor)
    Abstract
    There are several methods for measuring thin film thickness, however, for the analysis of liquid film motors [1] we need a method which is capable of measuring the thickness using a single image of the film. In this work, we use the colors that appear on thin films, such as soup bubbles, which is a result of light interference to calculate the thickness of the layer  

    Thermal Relaxation Time Of Healthy and Cancerous Tissue In Pulsed Laser Using Monte Carlo Simulation

    , M.Sc. Thesis Sharif University of Technology Khaze, Mehran (Author) ; Amjadi, Ahmad (Supervisor)
    Abstract
    Thermal relaxation time is the time when maximum temperature of a particle get to 1/e of it’s initial value. The destruction of a tissue depends to this important parameter. This parameter has studied by Monte Carlo simulation of pulsed laser in to environment as healthy and cancerous tissue. The main goal of this method is providing proper temperature in a special area so that minimize thermal destruction around that area. In this thesis, temperature distribution of tissue that is caused by pulsed laser, has solved by new method;in this new method the pulse duration uses for Monte Carlo simulation. Also using the solution of radiation transfer equation by Discretes Ordinate Method, new... 

    Assessment of Effectiveness of the “Physical Asset Management Model” in Productivity of Maintenance System, Using ERP

    , M.Sc. Thesis Sharif University of Technology Amjadi, Ali (Author) ; Mostafavi, Mostafa (Supervisor)
    Abstract
    People in the organization who are influential, opinion leaders, decision-makers and approvers need to be incorporated into the entire Strategic Planning process at some levels .The Management of these Stakeholders involves identifying their organizational roles and their disposition towards and understanding of Strategic Planning, then to work with them throughout the process to improve or maintain their opinion of the value of Strategic Planning through continuous updating and addressing of their issues, concerns and questions. Physical asset practitioners apply the physical asset management framework and policies to ensure the performance and output potential of physical assets through... 

    Effect of Amplitude of Electric Field on the Rotation of Liquid Film

    , M.Sc. Thesis Sharif University of Technology Mashhadi, Meysam (Author) ; Amjadi, Ahmad (Supervisor)
    Abstract
    By direct and alternating electric field applied to thin film of liquid suspended in the air we can spin out and control it. Rotation pattern depends on the geometry of the electrodes and the applied magnetic field. This is called a rotating liquid film (Liquid Film Motor). To determine the cause of rotation, different models have been proposed. In this project we have tried to check the accuracy of any of the models. Using particle velocimetry using the photo, we calculate the velocity pattern. Then, using the Navier-Stokes equation calculate the acceleration and viscosity from the velocity. Then, for a special arrangement using a finite diffrent method, electric potential and the electric... 

    Design and Build an Acoustic Tweezers and Move up the Polystyrene Particles

    , M.Sc. Thesis Sharif University of Technology Ghavidel, Amir (Author) ; Amjadi, Ahmad (Supervisor)
    Abstract
    Ultrasound waves have attracted substantial attention due to their potential for trapping the small particles, which cannot be handled by usual tweezers. The acoustic tweezer is a technology that is able to tarp and control the movement of micrometer to millimeter objects by standing or focused sound waves. Acoustic tweezers are the subject of many researches around the world, due to simplicity, cost-effective, biocompatibility and most important better performance in non-transparent optical environments, compared with optical tweezers.In this project, by using a ring piezoelectric and a power amplifier, an acoustic tweezer was designed and constructed. Moreover, the polystyrene particles... 

    The Effects of Intentional Process Models on Goal Modeling and Process Conformance Checking

    , M.Sc. Thesis Sharif University of Technology Farsayyad, Nazi (Author) ; Rafiei, Majid (Supervisor) ; Khedmati, Majid (Supervisor)
    Abstract
    In recent years, requirement engineering and goal modeling have gained more attention among different organisations. Therefore, different methods have been designed to discover stakeholders’ requirements and translate them into process and organizational goals. Various goal models have been introduced to represent these goals and their relations towards each other. Still, these methods are manual representations of different process scenarios and do not relate to the actual behavior. In 2014, Map Miner Method (MMM) was introduced to discover intentional process models from event logs. MMM uses Hidden Markov Model (HMM) as a means to represent the process as a map model of strategies and... 

    Computer Simulation of Ultrasonic Waves in Cybernetic Glasses in Order to Increasing Spatial Resolution of Blinds

    , M.Sc. Thesis Sharif University of Technology Monajatipour, Fahimeh (Author) ; Amjadi, Ahmad (Supervisor)
    Abstract
    Eyesight is one of the most important tools for humans to communicate with environment and consequently, blindness or poor eyesight results in unsatisfactory effect on life quality. Owing to the importance of the sense and to assist to the patients, this thesis aims to design and assemble cybernetic glasses using ultrasound waves. To this end, firstly, the notion of waves focusing on ultrasound waves is described and reactions of human hearing system to the waves are studied. Then, the transducers as a key device are introduced. Afterward, bat sense system to communicate with environment which is based ultrasound waves is described. Next, attenuation effects on ultrasound wave pressures are... 

    A Trajectory Recommendation System for Efficient Finding of Passengers

    , M.Sc. Thesis Sharif University of Technology Aledavood, Ebrahim (Author) ; Khedmati, Majid (Supervisor) ; Rafiee, Majid (Supervisor)
    Abstract
    Recommending routes to city taxis in order to improve their performance in finding passengers can reduce traffic, pollution and waiting time for passengers, as well as this, increasing the efficiency of taxis can increase their income. In this study, by analyzing trajectory data obtained from 536 taxis in San Francisco over a period of one month, we generated networks of cells, each of which has time-dependent characteristics such as the probability of finding a passenger, the capacity of each cell, or the amount of demand exists is in the cell and the average speed of passing through that cell. also, the connections between these cells in order to make more use of the experiences of taxi... 

    Improving Artificial Neural Network Predictive Performance Using Panel Data

    , M.Sc. Thesis Sharif University of Technology Alirezaei, Hamid Reza (Author) ; Khedmati, Majid (Supervisor) ; Rafiee, Majid (Supervisor)
    Abstract
    The purpose of the present study is to develop neural network estimation method for hybrid or panel data which have a combination of two cross-sectional and time series structures and because of the features of both structures, their use in different sciences offers many advantages; and the analytical methods for this data structure are also different from other one-dimensional structures, so different and specific regression models are presented for this data structure. However, in the artificial neural network method, modeling the development for this data structure is neglected, so in the present study, using the concepts of panel regression methods and their application to the... 

    An in-vitro measurement of temperature changes in phacoemulsification system during different modes

    , Article 2nd International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2008, Shanghai, 16 May 2008 through 18 May 2008 ; 2008 , Pages 1569-1574 ; 9781424417483 (ISBN) Tahvildari, R ; Fattahi, H ; Amjadi, A ; Sharif University of Technology
    IEEE Computer Society  2008
    Abstract
    Ultrasound waves have been used in these days for most surgeries. They are applied to remove body tissues through surgery, for example in removing eye lens in cataract surgery. In a nutshell, a 3mm incision near cornea has been created and then after, a folded lens will be implanted and the patient can be released soon after the operation. The process is done by a vibrating metal tip in order to emulsify the lenses and the small particles will aspirate the debris through the hollow center of the tip. The problem of this procedure in some cases is thermal damage. This research addresses the aforementioned problem through an important parameter, different operating modes of the system. The... 

    Second Harmonic Generation (SHG) measurement affected by electric field

    , Article Scientia Iranica ; Volume 14, Issue 3 , 2007 , Pages 236-239 ; 10263098 (ISSN) Amjadi, A ; Rajai, P ; Latifi, H ; Sharif University of Technology
    Sharif University of Technology  2007
    Abstract
    A type II (eoe: extraordinary-ordinary-extraordinary) phase matching condition in a 2nd Harmonic Generation of Nd-YAG laser under a high electric field in a uniaxial KDP crystal has been measured. Type II phase matching takes place when the two mixing waves are of orthogonal polarizations (extraordinary-ordinary) and the 2nd harmonic radiation corresponds to an extraordinary wave. By applying an electric field along the X(Y) axes of the crystal, a new phase-matching angle was measured under the influence of different electric fields. The deflection angle of the SHG beam was measured as a function of the applied voltage. An optical collector will focus the 1st harmonic and a fraction of its... 

    The Effect of Polarization in Edge detection in Dispersive Medium

    , M.Sc. Thesis Sharif University of Technology Feiz, Mohammad Sadegh (Author) ; Amjadi, Ahmad (Supervisor)
    Abstract
    Introduction: Today, backward and forward scattering tomography of dispersive medium is of great interest because of its broad applications, especially in medical imaging, of breast cancer, Distinguishing different tissues of the body from each other is one of the necessities. Increasing the quality of the image by just a few percents has great improvement on the tomography resolution.
    Materials and Methods: In this project we made phantom of the tissue and tumor from Intralipid 10% plus Agarose and Indian ink for soft tissue and plastic fibers as tumor having birefringence factor of 0.001.After putting the plastic tumor in soft tissue phantom, the polarized white light and a digital...