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pourebrahim--majid
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Designing a LQR controller for an electro-hydraulic-actuated-clutch model
, Article Proceedings of 2016 2nd International Conference on Control Science and Systems Engineering, ICCSSE 2016, 27 July 2016 through 29 July 2016 ; 2016 , Pages 82-87 ; 9781467398725 (ISBN) ; Selk Ghafari, A ; Pourebrahim, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
During the past decade, Electro-Hydraulic system has performed a significant role in industrial engineering as an actuator for high performance and precision positioning applications. In this case, many control methods have been developed for an electro-hydraulic actuated clutch. In this paper a Linear Quadratic Regulators (LQR) is proposed to trajectory control of a wet clutch actuated by a hydraulic servo valve mechanism. Simulation study was performed using linearized mathematical model of the system implemented in MATLAB software. Based on the simulation results performance of the proposed controller was evaluated and discussed
Heat and Cooling Load Management through Minimizing the Heat Transfer and Utilizing the Storage Potential of Materials and Equipment Inside a Building
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor)
Abstract
Buildings are responsible for 40% of total energy consumption worldwide. A significant portion of this energy contributes to building temperature control, and energy storage is an effective way to reduce energy consumption and to levelize the supply of heat load. A solution for reducing energy consumption in the building is to increase the thermal inertia of the building and to store energy using smart materials in the building components. Materials with phase change can stabilize the internal temperature of the building.In the present study, model is exmined with the help of modeling the thermal behavior of a room in Tehran in summer, using MATLAB software. The problem is solved by the...
Design and Implementat of a Navigating Procedure for Robotic-assisted Fracture Reduction of Long Bones
, M.Sc. Thesis Sharif University of Technology ; Farahmand, Farzam (Supervisor)
Abstract
During femur fracture reduction surgery, both patients and surgeons are exposed to a great amount of radiation, which is harmful to their health. Computer-assisted orthopaedic surgery (CAOS) is a less invasive approach for its ability to reduce the usage of image intensifiers. Various robots have been developed for femur fracture reduction surgery. Most of these robots are based on serial architectures. Both low load-carrying capacity and poor accuracy are inherent to serial robots, which makes them inappropriate for femur fracture reduction. Some parallel robots using the “Stewart platform” have also been developed for femur fracture reduction, but their restricted workspace limits their...
Semi-supervised parallel shared encoders for speech emotion recognition
, Article Digital Signal Processing: A Review Journal ; Volume 118 , 2021 ; 10512004 (ISSN) ; Razzazi, F ; Sameti, H ; Sharif University of Technology
Elsevier Inc
2021
Abstract
Supervised speech emotion recognition requires a large number of labeled samples that limit its use in practice. Due to easy access to unlabeled samples, a new semi-supervised method based on auto-encoders is proposed in this paper for speech emotion recognition. The proposed method performed the classification operation by extracting the information contained in unlabeled samples and combining it with the information in labeled samples. In addition, it employed maximum mean discrepancy cost function to reduce the distribution difference when the labeled and unlabeled samples were gathered from different datasets. Experimental results obtained on different emotional speech datasets...
Fairness in Machine Learning
, M.Sc. Thesis Sharif University of Technology ; Foroughmand Araabi, Mohammad Hadi (Supervisor)
Abstract
As machine learning continues to be used extensively in all aspects of human life, especially social and legal decision making; Concerns have been raised about data-driven software and services biasing against certain demographic groups. Machine learning fairness, which refers to methods for correcting algorithmic bias in automated decision-making systems, is not only a social concern but also an industry need for developing human-centered tools.The study reviews studies on bias, fairness definitions, and attempts to reduce bias in machine learning models. Eventually, we suggest a method for reducing bias in imbalanced datasets
On the use of compressive sensing for image enhancement
, Article Proceedings - 2016 UKSim-AMSS 18th International Conference on Computer Modelling and Simulation, UKSim 2016, 6 April 2016 through 8 April 2016 ; 2016 , Pages 167-171 ; 9781509008889 (ISBN) ; Ghorshi, S ; Khoshnevis, S. A ; Pourebrahim, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Compressed Sensing (CS), as a new rapidly growing research field, promises to effectively recover a sparse signal at the rate of below Nyquist rate. This revolutionary technology strongly relies on the sparsity of the signal and incoherency between sensing basis and representation basis. Exact recovery of a sparse signal will be occurred in a situation that the signal of interest sensed randomly and the measurements are also taken based on sparsity level and log factor of the signal dimension. In this paper, compressed sensing method is proposed to reduce the noise and reconstruct the image signal. Noise reduction and image reconstruction are formulated in the theoretical framework of...
The Effects of Intentional Process Models on Goal Modeling and Process Conformance Checking
, M.Sc. Thesis Sharif University of Technology ; 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...
A Trajectory Recommendation System for Efficient Finding of Passengers
, M.Sc. Thesis Sharif University of Technology ; 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 ; 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...
Impelementation of Numerical Method For Hydrodynamic Behavior for Salvage of a Sunken Ship
, M.Sc. Thesis Sharif University of Technology ; Abbaspour, Majid (Supervisor)
Abstract
One of the utmost important factors during salvage operation of drowned ships is raising velocity. Uncontrolled raise is a dynamic phenomenon which can lead to the sudden tensions, collapse in airbags or ships. Studing this issue helps the engineers which kinds of problems are more important during salvage operations. This study focus on modeling and analysis of raising movment of the ship with FLOW-3D and ABAQUS software.
In FLOW-3D environment, hydrodynamic analysis of rising movment of drowned ship has been done. We should mention that applied forces and velocities and other parameters from the FLOW-3D output should be passed IMCA Criteria to avoid uncontrollable raise. In ABAQUS...
In FLOW-3D environment, hydrodynamic analysis of rising movment of drowned ship has been done. We should mention that applied forces and velocities and other parameters from the FLOW-3D output should be passed IMCA Criteria to avoid uncontrollable raise. In ABAQUS...
The Application of Profile Monitoring in Healthcare for Disease Monitoring- case Study
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
Profile Monitoring is a new research topics in the field of statistical process control. In many applications of statistical quality control, sometimes quality of a process or product described by a relationship between a response variable and one or more independent variables.The researchers call this relationship profile. The study seeks to demonstrate that monitoring profiles In addition, the industry can be effective in medical field and improves control of the patient's condition by a doctor. Profiles are usually modeled with a linear regression equation, non-linear or polynomial. finally, the results of this study, using actual data, models and methods to predict and control...
Experimental Study on Extracting Clean Energy from Vortex Induced Vibration
, M.Sc. Thesis Sharif University of Technology ; Abbaspour, Majid (Supervisor)
Abstract
Two experimental models were designed and tested to extract energy from vortex induced vibrations of a elastically mounted one degree of freedom rigid cylinder in the Reynolds range of 120000 < Re <220000. In the first model the amplitude and frequency of the movement was measured then a second model was designed to be tested in the Emam Hossein marine laboratory. The model was designed in a way that many of its properties like mass ratio, spring constant and damping coefficient were able to be altered. In this study the vortex induced vibration of an elastically mounted cylinder was scrutinized in high Reynolds and very low mass ratios for the first time and an amplitude ratio of 2.49 were...
Optimization of Radiotherapy Plan under Uncertainty
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
As a method of cancer treatment or improvement of cancer-related complications, external radiation therapy is prescribed by physicians, in case of detection of a tumor in a region of patient’s body. Over time, various techniques have been developed for external beam radiation therapy. Among which, Intensity Modulated Radiation Therapy (IMRT), due to its ability to adjust the intensity of radiation beams, has a higher capacity to generate appropriate dose distribution based on tumor size and volume and it is one of the most widely used techniques in cancer treatment centers.The core process in treatment planning is using appropriate computer algorithms which results in posing enough damage to...
Location and Relocation of Ambulances under Uncertainty Conditions
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
The aim of Emergency Medical Services (EMS) is to provide fast medical care and to transport patients to hospitals at the earliest possible time, so as to reduce injury and fatality rate. Healthcare managers try to improve healthcare systems by reducing the response time to demands. In this thesis, we present mathematical models for the problem of location and relocation of emergency vehicles after the end of their service time or after they have returned to a hospital. We believe that implementing these models can help managers improve the performance of emergency medical services. In the first part of this study, we present a two-level deterministic optimization model considering demand...
Selection of Resilience Supply Portfolio with Uncertainties
, M.Sc. Thesis Sharif University of Technology ; Rafie, Majid (Supervisor)
Abstract
Supplier selection and order quantity allocation problem is one of the most complex making decision problems comes into account. In the past, supplier selection done based on criteria such as price, quality and delivery time. Today's supply chains with the aim of expanding business activities and improving their performances, Follow process such as outsourcing, product development, and selection of multi-supplier strategies. This conditions will bring opportunities and threats for supply chains. One of the possible risks to supply chains are disruption risks and disruption has been a great concern in the past decade and disruption of suppliers are one of the new topics that have recently...
Transplant Process Optimization in Kidney Donation Problem
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
At the present, End-stage renal disease(ESRD) is the ninth-leading cause of death in the USA.according methods of medical treatment for End-stage renal disease (ESRD), transplantation is the most viable renal replacement therapy for ESRD patients, there is a disparity between the demand for kidneys for transplantion and the supply. Incompatible inblood-type and antigen matching between patient-donor pairs is cause of shortage in disparity between the demand and the supply.paired kidney exchange of kidney among incompatible patient-donor pairs.PKE can be solve many difficulties in matching patient with incompatible donors. Kidney transplant surgeries in PKE must take place simultaneously...
Optimal Design of Hydrofoil for Marine Current Turbine
, M.Sc. Thesis Sharif University of Technology ; Abbaspour, Majid (Supervisor)
Abstract
Marine current power has been utilized in recent years as one of the most foreseeable renewable energy sources. In this study a multi-objective hydrofoil optimal design is carried out for use in marine current turbine in order to improve hydrodynamic performance due to low speed current in Qeshm channel. A particle swarm optimization code using FORTRAN is developed and coupled with XFoil software as flow solver that is based on panel method. B-spline curve is used to parameterize the hydrofoil shape and the coordinates values of the control points are designated to act as optimization parameters. Validity of flow solver examined by comparison made between computed data against experimental...
Proposing a Solution Algorithm for Operating Room Scheduling Problem Using Open Scheduling and Elective Patient Strategy
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
Operating rooms have always been the most expensive and also the most profitable section in hospitals which include approximately one third of cost and two third of income. The management always wants to decrease the cost of hospitals. On the other hand, usually this goal stands against other goals such as patient’s satisfaction. So the manager should make a balance between these goals. In this research, we will propose an integer programming model for operating room scheduling problem without uncertainty for elective patients. In order to make the model more realistic, we want to make connection between operating room theatre and intensive care units. Also, we will consider desirable...
Fluence Map Optimization in IMRT Planning under Uncertainty
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
Cancer is one of the main causes of death among all people around the world. This shows that more and more attention should be paid to cure cancer. One of the most common cancer treatments is radiation therapy. Among all radiation therapy treatments, Intensity-Modulated Radiation Therapy is a very effective and flexible ways to treat cancer. There are numerous mathematical problems to find the perfect treatment plan. One of these mathematical problems is Fluence Map Optimization in which we try to find the best dose intensity for each tumor and surrounding organs. The main purpose in this problem is to minimize the number of cancerous cells which are being destroyed while minimizing the...
Development of a Model to Investigate Energy Production Potential from Sea Applying GIS Technique
, M.Sc. Thesis Sharif University of Technology ; Abbaspour, Majid (Supervisor)
Abstract
The growing requirements for renewable energy production lead to the development of a new series of systems, including wave and tidal energy conversion systems. Due to their sensitivity and the impact of the aggressive marine environment, the selection of the most adequate location for these systems is a major and very important task. Several factors, such as technological limitations, environmental conditions, administrative and logistic conditions, have to be taken into account in order to support the decision for best location. The aim of the present study is to provide an Atlas of IRAN Offshore Renewable Energy Resources (hereafter called ‘the Atlas’) to map out wave and tidal resources...