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Failure analysis of a first stage gas turbine blade
, Article Engineering Failure Analysis ; 2010 ; 13506307 (ISSN) ; Abouali, S ; Akbari Garakani, M
2010
Spatiotemporal dynamics of chlorophyll-a in the Gorgan Bay and Miankaleh Peninsula biosphere reserve: Call for action
, Article Remote Sensing Applications: Society and Environment ; Volume 30 , 2023 ; 23529385 (ISSN) ; Danesh Yazdi, M ; Sharif University of Technology
Elsevier B.V
2023
Abstract
Gorgan Bay (GB) and Miankaleh Peninsula biosphere reserve has faced an endangering condition because of a significant water loss and quality degradation due to intensive eutrophication. However, a synoptic view of the spatiotemporal dynamic of eutrophication is missing. In this study, we first used MODIS data to trace the long-term trend of eutrophication in GB between 2003 and 2021. To investigate the intra-annual variability of Chl-a in GB at a much higher spatial resolution, we developed an Artificial Neural Network (ANN) algorithm that uses Sentinel-2 imagery to map monthly Chl-a in the water year 2020–2021. Finally, we explored the major physical controls on eutrophication in GB....
Experimental Study of Mechanical Behavior of a Particular Metallic Material under Cyclic Loading
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
One of the requirements of designing structures is the properties of their materials. The behavior of the material should be studied under the same conditions (loading regime) as it would be in practice. Regarding the structures which are subjected to cyclic loading, usually the results of monotonic tests on their material are used for their analysis under cyclic loads. Taking this fact into account that the behavior of materials under cyclic loading is normally much different from that under monotonic loading, one should doubt the results of the analyses of structures subjected to cyclic loading for which monotonic test results are used. In this project, the properties of steel rebars under...
New techniques for localization based information theoretic secret key agreement
, Article 2017 14th International ISC (Iranian Society of Cryptology) Conference on Information Security and Cryptology, ISCISC 2017, 6 September 2017 through 7 September 2017 ; 2018 , Pages 70-76 ; 9781538665602 (ISBN) ; Mirmohseni, M ; Aref, M. R ; Sharif University of Technology
2018
Abstract
We consider a source model for information theoretic secret key agreement based on the distance among the nodes, in a basic system consisting of two legitimate users and an eavesdropper. The legitimate nodes try to agree on a reliable and secure key based on their noisy observation of distance between them. We propose two methods to enhance system utility: 1) Artificial Noise Forwarding (ANF), 2) transmission in different beam directions (multi-antenna transmission). In the first method artificial noise is used to worsen e a vesdropper's distance estimation and in the second method beacon signals are sent in different directions and the virtual distances in different beam directions are used...
Private authentication: optimal information theoretic schemes
, Article 2019 IEEE Information Theory Workshop, ITW 2019, 25 August 2019 through 28 August 2019 ; 2019 ; 9781538669006 (ISBN) ; Mirmohseni, M ; Aref, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
The main security service in the connected world of cyber physical systems necessitates to authenticate a large number of nodes privately. In this paper, the private authentication problem is considered, that consists of a certificate authority, a verifier, many legitimate users (prover) and any arbitrary number of illegitimate users. Each legitimate user wants to be authenticated (using his personal key) by the verifier, while simultaneously wants to stay completely anonymous (even to the verifier and the CA). On the other hand, an illegitimate user must fail to authenticate himself. We analyze this problem from an information theoretical perspective. First, we propose a general interactive...
Anonymous Mutual Authentication: An Information Theoretic Framework
, Article 9th Iran Workshop on Communication and Information Theory, IWCIT 2021, 19 May 2021 through 20 May 2021 ; 2021 ; 9781665400565 (ISBN) ; Mirmohseni, M ; Aref, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
We consider the anonymous mutual authentication problem, which consists of a certificate authority, single or multiple verifiers, many legitimate users (provers) and any arbitrary number of illegitimate users. The legal verifier and a legitimate user must be mutually authenticated to each other using the user's key, while the identity of the user must stay unrevealed. An attacker (illegitimate prover) as well as an illegal verifier must fail in authentication. A general interactive information theoretic framework in a finite field is proposed, where the normalized total key rate as a metric for reliability is defined. Maximizing this rate has a trade-off with establishing anonymity. The...
Quantifying the Relative Share of Factors in Drying Gorgan Bay and Miankaleh Peninsula by Studying Long-Term Water Balance
, M.Sc. Thesis Sharif University of Technology ; Danesh Yazdi, Mohammad (Supervisor)
Abstract
GB and Miankale Wetland are one of the most valuable water areas in the country from an ecological perspective, providing a habitat for a wide range of aquatic species and birds as well as providing a platform for fishing and tourism for locals. Recently, this wildlife refuge has experienced a crisis of reduced water levels and degraded water quality. Past studies have examined how fluctuations in the Caspian Sea water level affect GB's water quantity and quality. Due to the critical situation of Gorgan Bay, other factors affecting its water balance and upstream basin need to be examined, such as ground water flow and consumption, precipitation, and evaporation, and how they all affect the...
User and Data Privacy: An Information-Theoretic Approach
, Ph.D. Dissertation Sharif University of Technology ; Aref, Mohammad Reza (Supervisor)
Abstract
Today, ensuring privacy alongside other security features is essential for many services, and with the advancement of various technologies, different aspects of privacy are emerging. In most systems, establishing privacy is a challenging issue that may conflict with other system features or reduce the effectiveness of other system parameters. This dissertation studies privacy from the perspective of information theory in authentication as one of the significant security challenges. Applications of this issue include vehicular networks, sensor networks, and services based on blockchain technology. We consider various privacy features in the authentication problem, which includes a certificate...
A utilization of wireless sensor network in smart homes, reviewing its combination with modern cellular networks
, Article Proceedings of the 2011 International Conference on Communication and Industrial Application, ICCIA 2011, 26 December 2011 through 28 December 2011 ; December , 2011 , Page(s): 1 - 5 ; 9781457719172 (ISBN) ; Rafiei Sakhaei, M. H ; Sharif University of Technology
2011
Abstract
In this paper, after reviewing the basic structure for implementing WSN in smart grid, we would give a case study for implementation of such a structure in a smart home. It will be shown that using new generation cellular network structure, gives a basic improvement the infrastructure needed for gathering the information and taking a real time monitoring and control of a simplified model of a smart grid executed as a smart home. We will take the advantage of computer simulations to show the reliability of this method and finally, we will analyze the advantages of using this proposed structure in a smart grid. [1, 4]
Failure analysis of a repaired gas turbine nozzle
, Article Engineering Failure Analysis ; 13506307 (ISSN) ; Abouali, S ; Akbari Garakani, M ; Sharif University of TechnologyThe Study of the Effect of Surfactant on the Liquid Drop Motion In Fluid
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Co-Supervisor)
Abstract
The drop motion in fluid and the mass transfer is one of the most interesting and favorite topics that has attracted the attention of many researchers. Knowing the functions of the factors affecting the deformation and the process of mass transfer and the effects of the addition of the surfactant, improve the efficiency of the related industrial processes.In this regard, the present study examines how the shape and speed of a moving Newtonian drop in a Newtonian fluid, the mass transfer of soluble material from inside the drop to the surrounding fluid and also the study of the effect of surfactant on the dynamics of moving droplet is studied numerically. During the drop movement, the...
Down from the pedestal: Revisiting the exploit of literature in EFL language classes
, Article International Journal of Applied Linguistics and English Literature ; Volume 4, Issue 2 , 2015 , Pages 158-168 ; 22003592 (ISSN) ; Lari, Z ; Mosalli, Z ; Sharif University of Technology
Australian International Academic Centre PTY LTD
2015
Abstract
According to Arthur (2006, p. 200), “Through the use of literature, a language learning experience might become at the same time a source of immediate pleasure and satisfaction for the student. This possibility makes literature an appealing teaching device for ESL teachers”. However, numerous factors may contribute to the teachers’ lack of interest in using literary texts as a teaching tool. This study was an attempt to investigate Iranian EFL teachers’ attitude toward using literature in language classes and their perception toward the probable reasons of some teachers’ lack of interest in doing so. Altogether forty-four language teachers (19 females and 25 males, with a mean age of 26)...
Inclusion of carbon nanotubes in a hydroxyapatite sol-gel matrix
, Article Ceramics International ; Volume 35, Issue 7 , 2009 , Pages 2987-2991 ; 02728842 (ISSN) ; Nemati, Z. A ; Sadeghian, Z ; Sharif University of Technology
2009
Abstract
In this study, the inclusion of multi-walled carbon nanotubes as the second phase in the hydroxyapatite matrix, in order to improve the mechanical strength, has been performed via the sol-gel process. The stability of carbon nanotube sol with the changes of pH and dispersant values (sodium dodecyl sulfate) was evaluated by zeta potential analysis. The results indicated that synthesis of hydroxyapatite particles in the presence of the carbon nanotubes had the best result in homogenization of the carbon nanotube dispersion and faster crystallization of hydroxyapatite. The crystallization of hydroxyapatite phase was investigated with differential scanning calorimetry (DSC) and X-ray diffraction...
Fourier optics approach in evaluation of the diffraction and defocus aberration in three-dimensional integral imaging
, Article Computational Modelling of Objects Represented in Images: Fundamentals, Methods and Applications III - Proceedings of the International Symposium, CompIMAGE 2012 ; 2012 , Pages 81-84 ; 9780415621342 (ISBN) ; Kavehvash, Z ; Mehrany, K ; Sharif University of Technology
CRC
2012
Abstract
The unwanted effects of diffraction and defocus aberration in three-dimensional integral imaging are taken into account by using the Fourier optics approach. The concepts of point spread function and optical transfer function widely in use for conventional two-dimensional imaging are generalized and applied to three-dimensional integral imaging systems. The effects of diffraction and defocus aberration are then studied and the performance of the conventional single lens imaging system is compared against that of the integral imaging
Multi-target sputter deposition of Ni50Ti 50 - XHfx shape memory thin films for high temperature microactuator application
, Article Sensors and Actuators, A: Physical ; Volume 121, Issue 2 , 2005 , Pages 543-548 ; 09244247 (ISSN) ; Cao, Y. Z ; Barber, Z. H ; Sharif University of Technology
2005
Abstract
High temperature shape memory NiTiHf thin films with varying hafnium contents up to 28.7 at.% were fabricated by DC magnetron sputtering using simultaneous sputter deposition from separate elemental targets. The required film composition was achieved by adjusting the power ratio to the targets. The as-deposited films were amorphous; a post deposition annealing was performed at 550 °C to crystallize the films. Two-micron thick films were characterized by energy dispersive spectroscopy in a scanning electron microscope, temperature controlled X-ray diffraction, differential scanning calorimetry, and atomic force microscopy. The results showed that above 10 at.% Hf additions the transformation...
Strong Revenue (Non-)Monotonicity of Single-parameter Auctions
, Article EC 2023 - Proceedings of the 24th ACM Conference on Economics and Computation ; 2023 , Pages 452-471 ; 979-840070104-7 (ISBN) ; Huang, Z ; Majdi, D ; Yan, Z ; Sharif University of Technology
Association for Computing Machinery, Inc
2023
Abstract
Consider Myerson's optimal auction with respect to an inaccurate prior, e.g., estimated from data, which is an underestimation of the true value distribution. Can the auctioneer expect getting at least the optimal revenue w.r.t. the inaccurate prior since the true value distribution is larger? This so-called strong revenue monotonicity is known to be true for single-parameter auctions when the feasible allocations form a matroid. We find that strong revenue monotonicity fails to generalize beyond the matroid setting, and further show that auctions in the matroid setting are the only downward-closed auctions that satisfy strong revenue monotonicity. On the flip side, we recover an approximate...
Subsidy cut and its effect on tehran electricity company: A system dynamics approach
, Article Proceedings of the 2012 - Summer Computer Simulation Conference, SCSC 2012, Part of SummerSim 2012 Multiconference ; Volume 44, Issue 10 , 2012 , Pages 113-120 ; 9781618399847 (ISBN) ; Fard, S. Z
2012
Abstract
In recent years, subsidy payment has been made a main challenge for governments due to growth of population and energy price in global markets. Targeted subsidy plan has been implemented in Iran since last year, and this article discusses its effects on costs and revenues of Tehran Electricity Company as one of the major subdivisions of Iran's electricity industry. In the new system, structural changes have been made in electricity tariffs, so it is not possible to predict the future trends in electricity consumption only based on the past consumptions. In order to model the decision making structure in the recent conditions, a system dynamics method is applied. In addition to modeling the...
Interactions of coinage metal clusters with histidine and their effects on histidine acidity; Theoretical investigation
, Article Organic and Biomolecular Chemistry ; Volume 10, Issue 47 , Oct , 2012 , Pages 9373-9382 ; 14770520 (ISSN) ; Jamshidi, Z ; Tehrani, Z. A ; Fattahi, A ; Sharif University of Technology
2012
Abstract
Understanding the nature of interaction between metal nanoparticles and biomolecules such as amino acids is important in the development and design of biosensors. In this paper, binding of M3 clusters (M = Au, Ag and Cu) with neutral and anionic forms of histidine amino acid was studied using density functional theory (DFT-B3LYP). It was found that the interaction of histidine with M3 clusters is governed by two major bonding factors: (a) the anchoring N-M and O-M bonds and (b) the nonconventional N-H⋯M and O-H⋯M hydrogen bonds. The nature of these chemical bonds has been investigated based on quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analyses. In the next...
Can anion interaction accelerate transformation of cytosine tautomers? Detailed view form QTAIM analysis
, Article Structural Chemistry ; Volume 23, Issue 6 , 2012 , Pages 1843-1855 ; 10400400 (ISSN) ; Tehrani, Z. A ; Fattahi, A ; Jamshidi, Z ; Sharif University of Technology
2012
Abstract
The relative stabilities and noncovalent interactions of the six low-lying energy tautomers of cytosine nucleobase with some biological anions (such as F-, Cl-, and CN-) have been investigated in gas phase by density functional theory (DFT) method in conjunction with 6-311++G (d,p) atomic basis set. Furthermore, to systematically investigate all possible tautomerisms from cytosine induced by proton transfer, we describe a study of structural tautomer interconversion in the gas phase and in a continuum solvent using DFT calculation. We carried out geometrical optimizations with the integral equation formalism of polarizable continuum (IEF-PCM) model to account for the solvent effect, and the...
Interactions of glutathione tripeptide with gold cluster: Influence of intramolecular hydrogen bond on complexation behavior
, Article Journal of Physical Chemistry A ; Volume 116, Issue 17 , 2012 , Pages 4338-4347 ; 10895639 (ISSN) ; Jamshidi, Z ; Javan, M. J ; Fattahi, A ; Sharif University of Technology
2012
Abstract
Understanding the nature of the interaction between metal nanoparticles and biomolecules has been important in the development and design of sensors. In this paper, structural, electronic, and bonding properties of the neutral and anionic forms of glutathione tripeptide (GSH) complexes with a Au 3 cluster were studied using the DFT-B3LYP with 6-31+G**-LANL2DZ mixed basis set. Binding of glutathione with the gold cluster is governed by two different kinds of interactions: Auâ€"X (X = N, O, and S) anchoring bond and Au··•·•H-X nonconventional hydrogen bonding. The influence of the intramolecular hydrogen bonding of glutathione on the interaction of this peptide with the gold cluster has been...