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asadpour--abdoreza
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Damage Detection and Evaluation of Repair Materials and Techniques for Concrete Bridges
, M.Sc. Thesis Sharif University of Technology ; Joghataie, Abdoreza (Supervisor)
Abstract
Poor maintenance of concrete bridges in the past years in Iran, caused serious damages, so most of them need rehabilitation. The majority of repaired members are exposed to repeated damage because compatibility of repair material to substrate concrete not considered as well as weather and loading conditions. This study attempts to improve the repair achievement and durability of concrete bridges. This investigation contains two phases: preliminary study and experimental phase. Preliminary study attends to detect different types of damages of concrete bridges and their causes along with their propagation. The next part of this study discusses about various types of repair materials. In...
Synthesis and Characterization of ATPEG-PMDA Hydrogels Conjugated with Thermo-Responsive Coated Magnetic Nanoparticles for Cartilage Tissue Engineering
, M.Sc. Thesis Sharif University of Technology ; Simchi, Abdoreza (Supervisor)
Abstract
A novel thermo responsive decorated system is designed by coating Fe3O4 magnetic nanoparticles with conjugated Pluronic-ATPEG copolymer incorporated into the PEG-PMDA Hydrogel for drug delivery to the cartilage tissue. Grafted copolymer was synthesized by reaction between carboxylated Pluronic and amino terminated Poly ethylene glycol (ATPEG) and confirmed by FTIR and NMR analysis. The magnetic nanoparticles were modified with the produced copolymer and characterized by TEM, HRTEM, XRD, DLS, and VSM. A typical product has 13 nm magnetic core and 105 nm hydrodynamic diameter with narrow size distribution. DLS results showed that there was an increase in size by increasing temperature from 25℃...
Modeling Brachial Blood Pressure by Using Finger PPG Signal
, M.Sc. Thesis Sharif University of Technology ; Zahedi, Edmond (Supervisor)
Abstract
Nowadays, all of the devices that measure blood pressure commercially at home are using wrist or arm cuffs preventing the systolic or diastolic blood pressure from being measured continuously. Various parameters such as blood flow with some degree of correlation with blood pressure that can be measured noninvasively have been suggested. However, these parameters do not produce accurate estimates for blood pressure. Pulse Transit Time (PTT) which is defined as the interval between the R peak of ECG signal and the next PPG signal valley has shown to have over 90% correlation with systolic blood pressure in past studies. In this thesis, the relationship between the value of the systolic blood...
Scientific Choice, Its Effects of Values and Its Effects on Science
, M.Sc. Thesis Sharif University of Technology ; Golshani, Mehdi (Supervisor)
Abstract
This thesis seeks to demonstrate the importance (important status) of “subject” and “question” in science and also wants to show that choosing this issue is affected by values. There are various values, especially outside of science, which play role in subject choices made by scientists, scientific institutions and scientific policies, and therefore influence science by this way. So after giving an account of the term “scientific choice”, which has been proposed by Alvin Weinberg in 1963, we try to examine the impact of values on scientific choices and then the impact of these choices on science itself. In order to do this, we introduced choices in science and Weinberg’s index for them in...
Fiber output beam shape study using imaging technique
, Article Journal of Applied Sciences ; Volume 10, Issue 4 , 2010 , Pages 312-318 ; 18125654 (ISSN) ; Golnabi, H ; Sharif University of Technology
2010
Abstract
In this study the output beam profiles of the single mode and multimode optical fibers are investigated by the cross sectional imaging technique. Different experiments are performed for the single mode and multimode fibers and the captured images are compared. The relative near field intensity distribution and their relative changes with respect to the distance is examined and some fiber parameters are obtained. A similar pattern in the real-time image is observed for the two type fibers and major differences are discussed. Using this method it is possible to determine the numerical aperture of the illuminated fiber, which is about 0.22 for the tested fiber. The effect of coherency of the...
Double voting problem of some anonymous E-voting schemes
, Article Journal of Information Science and Engineering ; Volume 25, Issue 3 , 2009 , Pages 895-906 ; 10162364 (ISSN) ; Jalili, R ; Sharif University of Technology
2009
Abstract
In 1998, Mu and Varadharajan proposed an anonymous e-voting scheme to be applied in both small-scale and large-scale elections. They claimed that it protects the anonymity of voters and prevents double voting. They also mentioned that if a malicious voter votes more than once, his identity will be discovered by the election authority. In 2003, Lin et al. demonstrated that the scheme fails to resist double voting and further proposed an enhanced scheme to overcome the weakness. Their scheme has received a much of interest by Yang et al. (2004), Hwang et al. (2005), and Rodriguez-Henriquez et al. (2007). They have improved Lin et al.'s scheme to prevent their proposed weaknesses. This paper...
Beam profile and image transfer study in multimode optical fiber coupling
, Article Journal of Applied Sciences ; Volume 8, Issue 22 , 2008 , Pages 4210-4214 ; 18125654 (ISSN) ; Golnabi, H ; Sharif University of Technology
2008
Abstract
In this study the optical beam transfer and imaging in an optical fiber coupling is discussed. In coupling two fibers, some measurements from intensity perspective are performed and intensity profile is investigated. A theoretical model for the power transmission in fiber coupling is developed and theoretical function is compared with the experimental results. The amount of light delivered to the receiving fiber depends on the acceptance angle of the receiving fiber and the core cross sections of both fibers. Intensity profile function obtained theoretically agrees well with the measured results. The intensity variation as a function of the air gap variation is investigated in this article....
Brain waves evaluation of sound therapy in chronic subjective tinnitus cases using wavelet decomposition
, Article Frontiers in Integrative Neuroscience ; Volume 12 , 2018 ; 16625145 (ISSN) ; Jahed, M ; Mahmoudian, S ; Sharif University of Technology
Frontiers Media S.A
2018
Abstract
Management and treatment of subjective tinnitus is an ongoing focus of research activities. One of the most viable assessments of such treatment is the evaluation of brain activity in addition to patient response and clinical assessment. This study focuses on sound therapy and evaluation of patients’ electroencephalogram (EEG) in order to verify the potency of this approach. Broadband sound therapy was applied to nineteen participants aging from 25 to 64 and suffering from chronic subjective tinnitus to study the difference of brain activity, a) before fake treatment, b) after fake treatment and c) after the main treatment, using EEG and Visual Analog Scale (VAS) for evaluating Residual...
Aberrant frequency related change-detection activity in chronic tinnitus
, Article Frontiers in Neuroscience ; Volume 14 , 2020 ; Jahed, M ; Mahmoudian, S ; Sharif University of Technology
Frontiers Media S.A
2020
Abstract
Tinnitus is the perception of sound without the occurrence of an acoustic event. The deficit in auditory sensory or echoic memory may be the cause of the perception of tinnitus. This study considered the mismatch negativity (MMN) to investigate the potential difference between and within groups of persons with normal hearing (NH) and tinnitus. Using an auditory multi-feature paradigm to elicit the MMN, this study considered the MMN peak amplitude at two central frequencies for two MMN subcomponents. These central frequencies were 1 and 5 kHz, which the latter was closer to the perceived tinnitus frequency in the group with tinnitus. The deviants were higher frequency, lower frequency, higher...
Anonymous authentication protocol for GSM networks
, Article International Journal of Security and Networks ; Volume 3, Issue 1 , 2008 , Pages 54-62 ; 17478405 (ISSN) ; Sattarzadeh, B ; Movaghar, A ; Sharif University of Technology
Inderscience Publishers
2008
Abstract
In this paper, we propose a new anonymous channel protocol for authentication in GSM mobile communication networks. The protocol is the result of incorporating our anonymity scheme to an efficient GSM authentication protocol proposed by Chang et al. As a result, our protocol has all the features of their scheme including anonymity. Compared with the most recent protocols in this area, such as those by Peinado and Hwang et al., we show that our scheme generally is more secure and more efficient. © 2008, Inderscience Publishers
Enhanced smart-card-based authentication scheme providing forward-secure key agreement
, Article 1st IFIP International Conference on New Technologies, Mobility and Security, NTMS 2007, Paris, 2 May 2007 through 4 May 2007 ; 2007 , Pages 447-458 ; 9781402062698 (ISBN) ; Sattarzadeh, B ; Jalili, R ; Sharif University of Technology
Kluwer Academic Publishers
2007
Abstract
Many smart-card-based remote authentication schemes have been proposed recently. In 2004, Yoon et al. presented an improved scheme which is the leading of a research track started from Sun, 2000. In this paper, we illustrate that Yoon et al.'s scheme is vulnerable to the parallel session attack and propose an enhancement of the scheme to resist that attack. In our scheme the parties further establish a forward-secure session key by employing only hash functions to protect the subsequent communications. We also demonstrate that our scheme has better security in comparison to other related works, while it does not incur much computational cost © 2007 Springer
Seismic analysis of Tehran Telecommunication Tower using complex fractional modulus
, Article Structural Design of Tall Buildings ; Volume 11, Issue 5 , 2002 , Pages 353-373 ; 10628002 (ISSN) ; Safi, M ; Asadpour, N ; Sharif University of Technology
2002
Abstract
Seismic response of large concrete tower structures with passive or active damping is important in terms of performance under earthquake loads. The conventional finite element method has been used successfully in linear and nonlinear analyses in large concrete structures. The method can be performed by subdividing the large structure into small uniform elements having approximate shape functions. Although this replaces a single complicated structural system with a number of simple uniform elements, in cases of tall concrete tower structures with cracking and crushing behaviour in the concrete material and yielding in the reinforcement, the computer time and memory can be large. Hence, it is...
Global nonlinear dynamic analysis of concrete chimneys in frequency domain
, Article ACI Structural Journal ; Volume 101, Issue 3 , 2004 , Pages 341-350 ; 08893241 (ISSN) ; Safi, M ; Asadpour, N ; Sharif University of Technology
2004
Abstract
The conventional finite element method has been used successfully in linear and nonlinear analyses in concrete chimney structures. The method can be performed by subdividing the large structure into small uniform elements having approximate shape functions. Although this replaces a single complicated structural system into a number of simple uniform elements, in cases of tall concrete chimney structures with cracking and crushing behavior in concrete material and yielding in the reinforcement, the computer time and memory can be large. Hence, it is desirable to search for a procedure requiring a fewer number of elements and also less computer time and effort to model a structure. In this...
Damped spectral element method for global dynamic analysis of chimneys
, Article Advances in Structural Engineering ; Volume 7, Issue 1 , 2004 , Pages 33-47 ; 13694332 (ISSN) ; Safi, M ; Asadpour, N ; Sharif University of Technology
Multi-Science Publishing Co. Ltd
2004
Abstract
Conventional finite element method has been used successfully in linear and nonlinear analyses in tall chimney structures. The method can be performed by subdividing the large structure with small uniform elements having approximate shape functions. Although this replaces a single complicated structural system with the number of simple uniform elements, in cases of tall concrete chimney structures with cracking and crushing behavior in concrete material and yielding in the reinforcement, the computer time and memory can be large. Hence, it is desirable to search for a procedure requiring lesser number of elements and also less computer time and effort to model a structure. In this respect,...
Cognitive memory comparison between tinnitus and normal cases using event-related potentials
, Article Frontiers in Integrative Neuroscience ; Volume 12 , 2018 ; 16625145 (ISSN) ; Alavi, A ; Jahed, M ; Mahmoudian, S ; Sharif University of Technology
Frontiers Media S.A
2018
Abstract
About 20 percent of people above 60 years old suffer from tinnitus though no definitive treatment has been found for it. Evaluation of electrical brain activity using Event-Related Potentials (ERPs) is one of the methods to investigate the underlying reasons of tinnitus perception. Previous studies using ERPs suggest that the precognitive memory in tinnitus groups is negatively affected in comparison to the normal hearing groups. In this study, cognitive memory has been assessed using visual and auditory P300 response with oddball paradigm. Fifteen chronic tinnitus subjects and six normal hearing subjects participated in the experiment. T-test with significance level of 0.05 was applied on...
Design and operation of an evanescent optical fiber sensor
, Article Optics and Lasers in Engineering ; Volume 45, Issue 1 , 2007 , Pages 12-18 ; 01438166 (ISSN) ; Bahar, M ; Razani, M ; Abrishami, M ; Asadpour, A ; Sharif University of Technology
2007
Abstract
Design and operation of an optical fiber sensor based on the intensity modulation is reported in this article. Two distinct mechanisms are considered for the optical power loss and the sensor operation is explained in terms of these effects. The dominant loss mechanism is found to be the evanescent loss and based on this phenomenon the optical fiber sensor is designed. Performance of this sensor is tested as a liquid level sensor for water and the experimental results are reported. The dry and wet signals for this probe are measured for a series of measurements and important factors concerning the design and operation of sensor are described. The precision of measured values, reproducibility...
Enhancement of Kerr nonlinearity at long wavelength in a quantum dot nanostructure
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 43, Issue 10 , August , 2011 , Pages 1759-1762 ; 13869477 (ISSN) ; Sahrai, M ; Sadighi Bonabi, R ; Soltani, A ; Mahrami, H ; Sharif University of Technology
2011
Abstract
The giant Kerr nonlinearity with reduced linear and nonlinear absorption in a four-level quantum dot by employing the tunnel coupling is investigated. It is shown that by enhancement of tunnel coupling value the Kerr nonlinearity increases and at the same time linear and nonlinear absorption reduces at the long wavelength which is very important for communicational applications. Enhanced of Kerr nonlinearity in a double quantum dots is investigated. It is found that the electron tunneling has an essential role to reducing the linear absorption and increasing the Kerr nonlinearity at long wavelength
The potential role of auditory prediction error in decompensated tinnitus: An auditory mismatch negativity study
, Article Brain and Behavior ; Volume 9, Issue 4 , 2019 ; 21623279 (ISSN) ; Daneshi, A ; Asadpour, A ; Mohsen, S ; Farhadi, M ; Mahmoudian, S ; Sharif University of Technology
John Wiley and Sons Ltd
2019
Abstract
Introduction: Some tinnitus subjects habituate to their tinnitus but some others do not and complain of its annoyance tremendously. Normal sensory memory and change detection processes are needed for detecting the tinnitus signal as a prediction error and habituation to tinnitus. The purpose of this study was to compare auditory mismatch negativity as the index of sensory memory and change detection among the studied groups to search for the factors involving in the perception of tinnitus and preventing habituation in decompensated tinnitus subjects. Methods: Electroencephalography was recorded from scalp electrodes in compensated tinnitus, decompensated tinnitus, and no tinnitus control...
Analysis of rTMS in Improvement of Tinnitus using EEG and fMRI
, M.Sc. Thesis Sharif University of Technology ; Jahed, Mehran (Supervisor) ; Asadpour, Abdureza (Co-Supervisor) ; Hani Tabatabaei, Mozhgan (Co-Supervisor) ; Mehrkian, Saiedeh (Co-Supervisor)
Abstract
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...