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farahbakhsh-mamaghani--fariba
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Scheduling of Operating Theatre Rooms Considering the Capacity of Post-Operating Rooms
,
M.Sc. Thesis
Sharif University of Technology
;
Salmasi, Nasser
(Supervisor)
Abstract
In this thesis, scheduling of surgery rooms is investigated and the objective is minimizing total patient’s departure time from the ward room in a flexible flow shop manner. Here, some constraints like the capacity of recovery rooms, no-wait motion between the rooms and machine eligibility restrictions ( , Σ ) are considered.For solving this problem,we proposed two mixed integer linear programming models for the research problem. Since the research problem is shown to be NP-complete, we developed several algorithm based on Tabu Search (TS) to heuristically solve it. In TS algorithm two different methods and one neighborhood structures are applied to generate initial solution and...
Cross layering design of IPv6 fast handover in mobile WiMAX
, Article ICT 2010: 2010 17th International Conference on Telecommunications, 4 April 2010 through 7 April 2010, Doha ; April , 2010 , Pages 304-308 ; 9781424452477 (ISBN) ; Sorooshi, M ; Sharif University of Technology
2010
Abstract
Over the past few years, rapid advances in wireless broadband networks have been driving the evolution of communication and network technologies towards new mobile services for users. Handover management is still one of the most challenging issues to be solved for seamless mobility in wireless networks. To support mobility on terminal stations mobile WiMAX has been standardized. Moreover to provide seamless communications for such network Fast Mobile IPv6 (FMIPv6) has been proposed by IETF. But for seamless handover, collaboration of layer 2 and layer 3 is required. Thus, there is a requirement for cross-layering design to support proper behavior of the MIPv6 nodes in WiMAX networks. In this...
Dynamic Portfolio Optimization Using Other Investor’s Portfolios
, M.Sc. Thesis Sharif University of Technology ; Fazli, Mohammad Amin (Supervisor)
Abstract
Portfolio optimization is a crucial concept in financial engineering, focusing on the efficient management of investment portfolios. In the realm of financial markets, a portfolio refers to a collection of investments held by individuals or companies, encompassing diverse assets. Specifically, a stock portfolio consists solely of stocks. The primary objective of portfolio optimization methods is to maximize returns while controlling risks. Within Tehran’s Stock Market, valuable data pertaining to the stock portfolios of big shareholders and their historical changes can be obtained. This dataset contains vital information that can be leveraged to optimize portfolios over time and formulate...
Modeling of Error in Approximate Multipliers for Neural Network Accelerators
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
In recent years, Deep Neural Networks have become essential tools, surpassing human capabilities in various applications, leading to their widespread integration into various everyday applications. However, a fundamental challenge of these networks lies in their substantial energy consumption, particularly concerning constrained electronic devices. To address this issue, numerous solutions have been proposed, encompassing software-based approaches such as network pruning, knowledge distillation, and network quantization. Moreover, hardware-oriented enhancements have also emerged, including the utilization of approximate circuits and approximate calculations within neural network...
Rapid emulation of approximate DNN accelerators
, Article Proceedings - IEEE International Symposium on Circuits and Systems ; 2024 ; 02714310 (ISSN); 979-835033099-1 (ISBN) ; Hosseini, S ; Kachuee, S ; Sharifkhani, M ; Sharif University of Technology
2024
Abstract
In recent years, Deep Neural Networks (DNNs) have become essential tools, surpassing human capabilities in various applications. To address the computational complexity of DNNs, specialized hardware accelerators and Approximate Computing (AC) techniques have emerged. This paper presents a novel stochastic method for efficiently emulating Approximate Multipliers (AMs) within DNNs. This method offers a significant 4× speedup compared to the fastest GPU-based platform and a remarkable 28.25× speedup compared to the latest CPU-based platform with variable bit widths. It serves as a valuable tool for selecting viable AM candidates and provides valuable insights, particularly in scenarios...
The effect of direct and cross-rolling on mechanical properties and microstructure of severely deformed aluminum
, Article Journal of Materials Engineering and Performance ; Vol. 23, Issue 1 , 2014 , pp. 115-124 ; ISSN: 10599495 ; Kazeminezhad, M ; Sharif University of Technology
2014
Abstract
Severely deformed commercial pure aluminum sheets by constrained groove pressing are direct and crossrolled. The grain size evolution and dislocation density during rolling are studied using Williamson-Hall analysis on x-ray diffraction patterns of the deformed samples. These results and optical microscopy observations show that subsequent direct or cross-rolling of constrained groove pressed aluminum can produce elongated fine grains. The minimum crystallite size is achieved after cross-rolling of constrained groove pressed samples. By direct-rolling or cross-rolling of annealed sheet, the maximum intensity in x-ray diffraction patterns remains on (200) like annealed aluminum but...
Seismic behavior of concrete moment frame reinforced with GFRP bars
, Article Composites Part B: Engineering ; Volume 163 , 2019 , Pages 324-338 ; 13598368 (ISSN) ; Khaloo, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this research, four types of concrete moment frame were designed with glass fiber reinforced polymer (GFRP) bars according to ACI 440.1R-15 and the seismic behavior was assessed using pushover analysis. The frames were three and five stories with two and three bays. A computer code was developed to calculate the amount of fiber reinforced polymer bars in beams of the frames. In order to evaluate nonlinear behavior in plastic hinge regions, sections of beams and columns were analyzed on the basis of moment-curvature diagram and also P-M interaction curve for columns. Performance levels of frames were determined considering ATC-40 criteria. Behavior of concrete moment frames reinforced with...
Covariance Statistic and a Significance Test for Selecting All Active Variables
in Lasso
,
M.Sc. Thesis
Sharif University of Technology
;
Abstract
Testing the significance of the predictor variables and finding an appropriate method for inference on the coefficients is an important question in the sparse linear regression setting. Covariance statistic is a new method that tries to give an answer to this question. This statistic is defined based on lasso fitted values, and when the true model is linear, this statistic has an Exp(1) asymptotic distribution under the null hypothesis (the null being that all truly active variables are contained in the current lasso model). From classical statistics, we have known some methods like chi-squared test for testing the significance of an additional variable between two nested linear models. But...
Fabrication and Optimization of Organic Inorganic Perovskite Solar Cells Using Vapor Phase Deposition
, Ph.D. Dissertation Sharif University of Technology ; Taghavinia, Nima (Supervisor) ; Tajabadi, Fariba (Supervisor)
Abstract
In this research, we focus on study and fabrication of organic inorganic solar cells. We use and optimize various methods such as one-step spin-coating, two-step sequential deposition and vapor-assisted solution process (VASP), to prepare high quality perovskite films. One-step deposition is simplest method for deposition of perovskite films. Although perovskite deposition by this method is very simple, the control of uniformity and surface film morphology is difficult. Chlorine inclusion, optimization of annealing conditions, and a sequential solution-based deposition method have been demonstrated to increase film coverage and uniformity. Hence, we use sequential deposition method for...
Investigation of Quantum States of Light (Generation and Utilization Their Special Properties) in Quantum Information Science and Precision Measurements
, M.Sc. Thesis Sharif University of Technology ; Karimipour, Vahid (Supervisor)
Abstract
Quantum entanglement and superposition are wonderful and mysterious phenomena of quantum mechanics. By means of quantum entanglement, two or more systems become partner in state of each other . As a result, measurements on each of these systems affect the status of other systems. Quantum superposition allows a system inhabits several of its possible quantum states simultaneously. These two features are applicable in many technologies in present age. Photons, as an quantum unit of light, are appropriate candidate for utilization these properties. Because they are robust to decoherence and for their preparation exist various methods. Hence, we interested to generation of quantum states of...
Optimal Control of Switched Systems
, M.Sc. Thesis Sharif University of Technology ; Mahdavi-Amiri, Nezam (Supervisor)
Abstract
We consider the problem of optimal control of switched systems. In order to solve this problem, by using the Lagrange interpolation, we transform it into an equivalent nonlocal optimal control problem, and then by applying several conditions we transform it into a moment problem. This way, a nonlinear and non-convex optimal control problem is converted to an equivalent optimal control problem with linear and convex structure, which allows us to obtain an equivalent convex formulation of the problem. So we obtain an approximation of the unknown function by using the Lagrange interpolation, and an approximation of the integral term by using the trapezoidal method. Finally, we solve the problem...
A Study on Action Selection Deficits in Schizophrenic Patients Using Computational Modeling in Reniforcement Learning Framework
, M.Sc. Thesis Sharif University of Technology ; Vosoughi Vahdat, Bijan (Supervisor) ; Bahrami, Fariba (Supervisor)
Abstract
Schizophrenia is a devastating disorder that steals the opportunity of having a normal life from the sufferers. Drugs used in treating this disorder usually target psychotic symptoms and do not affect negative symptoms effectively. One of the deficits falling into this category is the impaired reversal learning. These patients usually learn the rules but do not renounce them after the contingencies of reward have been reversed. To investigate the reasons of this impairment, first a hypothesis of how different parts of the brain communicate during reversal learning is proposed using the physiological evidence. Then considering the known relation between the actor-critic model of the...
Can a multi-hop link relying on untrusted amplify-and-forward relays render security?
, Article Wireless Networks ; Volume 27 , November , 2020 , pages 795–807 ; Kuhestani, A ; Behroozi, H ; Sharif University of Technology
Springer
2020
Abstract
Cooperative relaying is utilized as an efficient method for data communication in wireless sensor networks and the Internet of Things. However, sometimes due to the necessity of multi-hop relaying in such communication networks, it is challenging to guarantee the secrecy of cooperative transmissions when the relays may themselves be eavesdroppers, i.e., we may face with the untrusted relaying scenario where the relays are both necessary helpers and potential adversary. To obviate this issue, a new cooperative jamming scheme is proposed in this paper, in which the data can be confidentially communicated from the source to the destination through multiple untrusted relays. In our proposed...
Can a multi-hop link relying on untrusted amplify-and-forward relays render security?
, Article Wireless Networks ; Volume 27, Issue 1 , 2021 , Pages 795-807 ; 10220038 (ISSN) ; Kuhestani, A ; Behroozi, H ; Sharif University of Technology
Springer
2021
Abstract
Cooperative relaying is utilized as an efficient method for data communication in wireless sensor networks and the Internet of Things. However, sometimes due to the necessity of multi-hop relaying in such communication networks, it is challenging to guarantee the secrecy of cooperative transmissions when the relays may themselves be eavesdroppers, i.e., we may face with the untrusted relaying scenario where the relays are both necessary helpers and potential adversary. To obviate this issue, a new cooperative jamming scheme is proposed in this paper, in which the data can be confidentially communicated from the source to the destination through multiple untrusted relays. In our proposed...
Pricing of Service Advance Sale System with Risk Consideration
, M.Sc. Thesis Sharif University of Technology ; Sheikhzadeh, Mehdi (Supervisor)
Abstract
Today service sector is an important part of economy in many countries and it accounts for a great portion of GDP in developed countries. The importance of the service sector has led to an expansion in research worldwide on services. Service has some unique specifications that make it different from product and research in this field is more challenging than production field. Pricing is one of the great challenges in service sector. Due to its intangibility and perishability, managing and pricing of service is complicated and ervice firms consistently seek for method and approaches to better manage their demand, capacity and prices. Advance sale is an effective approach which is commonly...
The Effect of Direct and Cross Rolling on Mechanical Properties and Microstructure of Severely Deformed Aluminium
, M.Sc. Thesis Sharif University of Technology ; Kazeminezhad, Mohsen (Supervisor)
Abstract
Recently, the severe plastic deformation (SPD) is known as one of the most used methods in decreasing the grain size and increasing the strength of metals. In this study, aluminum 1100was subjected toconstrained groove pressing (CGP) at room temperature. The CGPed samples in nanoscale structure, with different CGPed passes were direct rolled and cross-rolled in different rolling strains. Finally, all of the samples were annealed at temperatures of 100, 200 and 300 ° C for 30 min. It was observed that with increasing number of CGP passes and rolling strain the structure became more laminate and finer. With increasing rolling strain, the cross-rolling had greater effect on the microstructure...
Improvment of Perovskite Layer and Perovskite/Hole Transport Layer Interface to Inhance Perovskite Solar Cell Performance
, Ph.D. Dissertation Sharif University of Technology ; Taghavinia, Nima (Supervisor) ; Tajabadi, Fariba (Supervisor)
Abstract
The use of renewable energy sources has received much attention due to the increasing need for energy, limited energy resources and the pollution of fossil fuels. Among all types of solar energy conversion technology, photovoltaics has the highest technical potential and Iran’s geographical location is very suitable for benefiting from this energy. So, in this thesis, the fabrication and characterization of nanostructured solar cells based on organic-inorganic perovskites have been investigated. Many research goups have tried to increase the efficiency of perovskite solar cells. The efficiency of this kind of solar cells depends mainly on the light-absorbing layer (perovskite) and its...
Magneto-mechanical stability of axially functionally graded supported nanotubes
, Article Materials Research Express ; Volume 6, Issue 12 , 2019 ; 20531591 (ISSN) ; Mirtalebi, H ; Ahmadian, M. T ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
In this paper, size-dependent vibration analysis of axially functionally graded (AFG) supported nanotubes conveying nanoflow under longitudinal magnetic fields are performed, aiming at performance improvement of fluid-interaction nanosystems. Either the density or the elastic modulus of the AFG nanotube varies linearly or exponentially along the axial direction. Based on the nonlocal continuum theory, the higher-order dynamical equation of motion of the system is derived considering no-slip boundary condition. Galerkin discretization technique and eigenvalue analysis are implemented to solve the modeled equation. The validity of the simplified model is justified by comparing the results with...
Magneto-mechanical stability of axially functionally graded supported nanotubes
, Article Materials Research Express ; Volume 6, Issue 12 , 2019 ; 20531591 (ISSN) ; Mirtalebi, H ; Ahmadian, M. T ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
In this paper, size-dependent vibration analysis of axially functionally graded (AFG) supported nanotubes conveying nanoflow under longitudinal magnetic fields are performed, aiming at performance improvement of fluid-interaction nanosystems. Either the density or the elastic modulus of the AFG nanotube varies linearly or exponentially along the axial direction. Based on the nonlocal continuum theory, the higher-order dynamical equation of motion of the system is derived considering no-slip boundary condition. Galerkin discretization technique and eigenvalue analysis are implemented to solve the modeled equation. The validity of the simplified model is justified by comparing the results with...
Vibration control and manufacturing of intelligibly designed axially functionally graded cantilevered macro/micro-tubes
, Article 13th IFAC Workshop on Intelligent Manufacturing Systems, IMS 2019, 12 August 2019 through 14 August 2019 ; Volume 52, Issue 10 , 2019 , Pages 382-387 ; 24058963 (ISSN) ; Ebrahimi Mamaghani, A ; Ahmadian, M. T ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In the last decade, extensive attention is devoted to intelligibly designed materials of macro/micro-structures containing the fluid flow. In this study, intelligent control and vibrational stability of cantilevered fluid conveying macro/micro-tubes utilizing axially functionally graded (AFG) materials are considered. The governing equation of motion of the system is derived based on modified couple stress theory and then is discretized using Galerkin method. A detailed investigation is carried out to elaborate the influence of various parameters such as material properties, axial compressive load, and Pasternak foundation on the dynamical behavior of the system, all of which are influential...