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jabbari--fattaneh
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The Role of Symmetry in Quantifying Information
, M.Sc. Thesis Sharif University of Technology ; Shafie, Afshin (Supervisor)
Abstract
In this thesis we want to discuss about a new approach about information. Using this approach, Scott Muller builds his formalism on two basic concepts: distinguishablity and symmetry. His claim is that there is an inverse relation between symmetry and information. It means that if we have a symmetric system we need less information (Than an asymmetric system) to describe it. Here, we are going to explore the role and significance of symmetry in probabilistic distributions of the double-slit experiment, and we want to show if there is a predetermined relation between symmetry and information or not.
Persian Statistical Natural Language Understanding Based on Partially Annotated Corpus
, M.Sc. Thesis Sharif University of Technology ; Sameti, Hossein (Supervisor)
Abstract
Spoken language understanding unit is one of the most important parts of a spoken dialogue system. The input of this system is the output of speech recognition unit. The main function of this unit is to extract the semantic information from the input utterances. There are two main types of approaches to do this task: rule-based approaches, and data-driven approaches. Today data-driven approaches are of more interest because they are more flexible and robust compared to the rule-based approaches. The main drawback of these methods is that they need a large amount of fully annotated or in some cases Treebank data. Preparing such data is time consuming and expensive. The goal of this thesis is...
Design and Optimization of T1 Flip Flop in Bi-Directional RSFQ Logic
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
Superconducting Rapid Single Flux Quantum (RSFQ) Logic, is very fast (up to about THz) and ultra low power circuit technology and is the most recent and fastest superconducting logic family. So far one of the difficulties in RSFQ logic is associated to reading the circuit states in particular flip flops. In prevalent RSFQ logic using T1 Flip Flop gate instead of the T Flip Flop, the non-destructive reading of the registered bit is possible. Through this approach, it also has some limits in particular circuits. Another idea of resolving this issue, is considering the very new bi-directional RSFQ logic, which is based on alternative changing the bias current through the Josephson junctions....
Conventional vs. temperature-gradient transient liquid phase bonding of stainless steel 304 using a multi-component (Fe–Ni–Mo–B) filler metal
, Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 53, Issue 11 , 2022 , Pages 4081-4100 ; 10735623 (ISSN) ; Ekrami, A ; Sharif University of Technology
Springer
2022
Abstract
The application of the multi-component Fe-based filler metals (FMs) for transient liquid phase (TLP) bonding of AISI 304 austenitic stainless steel has been overshadowed by dissimilar interlayers merely due to their shorter isothermal solidification time. However, the latter usually suffers from low efficiency in terms of mechanical properties even after homogenization of heat treatment. This study shows that by imposing a temperature gradient across the bond line during the TLP bonding process (TG-TLP), it is possible to reduce the isothermal solidification time significantly. This renews the interest in utilizing multi-component Fe-based FMs. In this regard, the TG-TLP bonding process was...
A New Robust Fault Detection Approach to Nonlinear Dynamical Systems
, M.Sc. Thesis Sharif University of Technology ; Sadati, Nasser (Supervisor)
Abstract
In this thesis the problem of optimal robust fault detection has been studied. Optimal Fault Detection Filter (FDF) design, by using a Linear Matrix Inequality (LMI) structure for both linear systems with polytopic uncertainties and nonlinear Lipschitz systems has been considered. In this regard, a novel LMI is introduced which is capable of calculating the maximum lower bound of H− index with great accuracy.Then, based on the parameter-dependent Lyapunov function and the property of having convexity in combination of certain state space equations, the result is extended to polytopic uncertain systems. Afterward the design of an optimal observer-based residual generator, in the sense of...
The Impact of the Complementarity of Factors of Production on the Welfare Gains from International Trade
, M.Sc. Thesis Sharif University of Technology ; Madanizadeh, Ali (Supervisor)
Abstract
To answer how large the welfare gains from international trade are, this thesis uses two main ideas: linkages and complementarity. A problem along the production chain can sharply reduce output under complementarity. In such a circumstance, international trade and importing in the sectors which are the weak links of the production chain, help solve this problem. Using a general equilibrium model, it is shown that, the complementarity of the intermediate goods assumption results in much higher welfare gains from international trade compared to similar international trade models which assume the substitutability of the intermediate goods
Calculation of four-point correlation function of logarithmic conformal field theory using AdS/CFT correspondence
, Article Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics ; Volume 548, Issue 3-4 , 2002 , Pages 237-242 ; 03702693 (ISSN) ; Rouhani, S ; Sharif University of Technology
2002
Abstract
We use the correspondence between scalar field theory on AdS and induced conformal field theory on its boundary to calculate correlation functions of logarithmic conformal field theory in arbitrary dimensions. Our calculations utilize the newly proposed method of nilpotent weights. We derive expressions for the four point function assuming a generic interaction term. © 2002 Elsevier Science B.V. All rights reserved
Using Decentralized Approach in Power Plants Preventive Maintenance Scheduling Problem
, M.Sc. Thesis Sharif University of Technology ; Modarres Yazdi, Mohammad (Supervisor)
Abstract
In this paper, a new method for handling power plants preventive maintenance scheduling problem is proposed in which a decentralized framework is applied in order to help the electricity markets to prevent data sharing. The new approach is the extension of alternating direction method of multipliers (ADMM) along with several heuristics and refinements to omit the effect of non-convexity of the problem. Since, the new methodmerely needs minimal information exchange, it is completely practical. In order to evaluate the performance of the proposed method, a case study based on generating system of Iran is presented. It is shown that the proposed model obtains acceptable results
Solid Mixing in Gas-solid Fluidized Bed with an Inlet Jet
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Because of unique features and numerous advantages, the fluidized bed has been considered as one of the most widely used process equipment in various industries. However, many aspects of the hydrodynamic behavior of the equipment are unknown. In this study, using simulation tool, hydrodynamic behavior and mixing process of binary solids particle mixture in the tapered fluidized bed with a jet at the entrance were studied. Eulerian – Eulerian multifluid model incorporating the kinetic theory of granular flow is used to simulate the gas-solid multiphase flow with open-source MFIX software. To increase the accuracy of the results standard k-ε turbulence model was used. Validation of results was...
Numerical modeling and experimental validation of microstructure in gray cast iron
, Article International Journal of Minerals, Metallurgy and Materials ; Volume 19, Issue 10 , 2012 , Pages 908-914 ; 16744799 (ISSN) ; Davami, P ; Varahram, N ; Sharif University of Technology
Springer
2012
Abstract
To predict the amount of different phases in gray cast iron by a finite difference model (FDM) on the basis of cooling rate (R), the volume fractions of total γphase, graphite, and cementite were calculated. The results of phase composition were evaluated to find a proper correlation with cooling rate. More trials were carried out to find a good correlation between the hardness and phase composition. New proposed formulas show that the hardness of gray cast iron decreases as the amount of graphite phase increases, and increases as the amount of cementite increases. These formulas are developed to correlate the phase volume fraction to hardness. The results are compared with experimental data...
Microstructural and Mechanical Properties of TLP Bonded SS 304 with Fe-base Interlayer
, M.Sc. Thesis Sharif University of Technology ; Ekrami, Ali Akbar (Supervisor)
Abstract
Cooling sandwich panels are one of the components of the heat exchangers used to cool the components of the sandwich panels . One of the applications of TLP Bonding for steel can be called cooling sandwich panels. In this research , TLP of 304 Stainless Steel , using Fe-base interlayer at 1200 C has been investigated . Cross section of bonded samples were examined by optical and scanning electron microscopes. Microscopy results revealed that 2h is sufficient for completion of isothermal solidification and there is no eutectic compound at bonding zone . Bonding in this condition resulted in the free precipitates in the diffusion affected area. By analyzing eutectic phase in bonding areas at...
Frequency limitation due to switching transition of the bias current in bidirectional RSFQ logic
, Article Journal of Superconductivity and Novel Magnetism ; Volume 30, Issue 12 , 2017 , Pages 3619-3624 ; 15571939 (ISSN) ; Zandi, H ; Fardmanesh, M ; Sharif University of Technology
2017
Abstract
Switching time limitations of the ac bias current of Josephson junctions in bidirectional rapid single flux quantum (RSFQ) logic circuits are investigated in order to determine the limits to the maximum possible operating frequency. We introduce a new approach based on modifying the bias current parameters and determining the inductance values in the circuit for reducing the switching transition time of the bias current through the junctions. We have simulated and optimized the timing and the operation of the bidirectional nondestructive readout and Josephson transmission line cells in this respect to demonstrate the results of utilizing the proposed approach. We successfully reduced the...
Classification of all 1/2 BPS solutions of the tiny graviton matrix theory
, Article Journal of High Energy Physics ; Issue 4 , 2005 , Pages 1-35 ; 10298479 (ISSN) ; Torabian, M ; Sharif University of Technology
2005
Abstract
The tiny graviton Matrix theory [1] is proposed to describe DLCQ of type IIB string theory on the maximally supersymmetric plane-wave or AdS5 × S5 background. In this paper we provide further evidence in support of the tiny graviton conjecture by focusing on the zero energy, half BPS configurations of this matrix theory and classify all of them. These vacua are generically of the form of various three sphere giant gravitons. We clarify the connection between our solutions and the half BPS configuration in script N sign = 4 SYM theory and their gravity duals. Moreover, using our half BPS solutions, we show how the tiny graviton Matrix theory and the mass deformed D = 3,script N sign = 8...
Persian language understanding using a two-step extended hidden vector state parser
, Article IEEE International Workshop on Machine Learning for Signal Processing, 18 September 2011 through 21 September 2011 ; September , 2011 , Page(s): 1 - 6 ; 9781457716232 (ISBN) ; Sameti, H ; Hadi Bokaei, M ; Sharif University of Technology
2011
Abstract
The key element of a spoken dialogue system is a spoken language understanding (SLU) unit. Hidden Vector State (HVS) is one of the most popular statistical approaches employed to implement the SLU unit. This paper presents a two-step approach for Persian language understanding. First, a goal detector is used to identify the main goal of the input utterance. Second, after restricting the search space for semantic tagging, an extended hidden vector state (EHVS) parser is used to extract the remaining semantics in each subspace. This will mainly improve the performance of semantic tagger, while reducing the model complexity and training time. Moreover, the need for large amount of data will be...
Mechanical and thermal stresses in FGPPM hollow cylinder due to radially symmetric loads
, Article Journal of Pressure Vessel Technology, Transactions of the ASME ; Volume 138, Issue 1 , 2016 ; 00949930 (ISSN) ; Meshkini, M ; Eslami, M. R ; Sharif University of Technology
2016
Abstract
In this paper, the general solution of steady-state 1D radially symmetric mechanical and thermal stresses and electrical and mechanical displacements for a hollow thick cylinder made of fluid-saturated functionally graded poro piezoelectric materials (FGPPMs) is developed. The general form of thermal and mechanical boundary conditions is considered on the inside and outside surfaces. A direct method is used to solve the heat conduction equation and nonhomogenous system of partial differential Navier equations, using complex Fourier series and power law functions method. The material properties, except the Poisson ratio, are assumed to depend on the radial variable r and they are expressed as...
A new semi-analytical modeling of steam-assisted gravity drainage in heavy oil reservoirs
, Article Journal of Petroleum Science and Engineering ; Volume 69, Issue 3-4 , 2009 , Pages 261-270 ; 09204105 (ISSN) ; Pishvaie, M. R ; Jabbari, H ; Sharif University of Technology
2009
Abstract
Thermal recovery by steam injection has proven to be an effective means of recovering heavy oil. Forecasts of reservoir response to the application of steam are necessary before starting a steam drive project. Thermal numerical models are available to provide forecasts. However, these models are expensive and consume a great deal of computer time. An alternative to numerical modeling is to use a semi-analytical model. The objective of the current study was to investigate thermal applications of horizontal wells for displacement and gravity drainage processes using analytical modeling as well as reservoir simulation. The main novelties presented in the paper are: a) the transient temperature...
Resonant reconciliation of convex-potential inflation models and the Planck data
, Article Physical Review D ; Volume 100, Issue 10 , 2019 ; 24700010 (ISSN) ; Sheikh Jabbari, M. M ; Sharif University of Technology
American Physical Society
2019
Abstract
We consider single field chaotic inflationary models plus a cosine modulation term, as in axion monodromy models, and augment them by a light scalar field with similar cosine coupling. We show that the power spectrum of curvature perturbations of this model is dominated by the one-loop contribution to the inflaton two-point function which is enhanced due to resonant interactions. This allows us to disentangle the scale of the scalar and tensor perturbations and hence, to suppress the ratio of tensor-to-scalar power spectra and alter the expression of the scalar spectral tilt from the simple chaotic models. Thus, our resonating module opens the way to reconcile chaotic models with convex...
Observable quantum loop effects in the sky
, Article Journal of Cosmology and Astroparticle Physics ; Volume 2020, Issue 6 , 2020 ; Sheikh Jabbari, M. M ; Sharif University of Technology
Institute of Physics Publishing
2020
Abstract
Expanding on [1], we analyze in detail the single field chaotic inflationary models plus a cosine modulation term, augmented by a light scalar field with inflaton dependent oscillatory mass term. We work out in detail the Feynman diagrams and compute one, two and in general estimate higher loop two and three point functions in the in-in formulation. We explicitly establish how the oscillatory mass term can amplify one-loop effects to dominate over the tree as well as the higher loop contributions. The power spectrum of curvature perturbations of this model is hence enhanced compared to the simple single field chaotic model. As a consequence, one can suppress the tensor to scalar ratio r and...
Two-dimensional numerical solution of steady withdrawal from the lens of freshwater in a tropical Island
, Article 2006 ASME Joint U.S.- European Fluids Engineering Division Summer Meeting, FEDSM2006, Miami, FL, 17 July 2006 through 20 July 2006 ; Volume 1 SYMPOSIA , 2006 , Pages 627-633 ; 0791847500 (ISBN); 9780791847503 (ISBN) ; Mohammadi, M. H ; Saeedpanah, I ; Sharif University of Technology
American Society of Mechanical Engineers
2006
Abstract
The work presented here is a study of the steady withdrawal of water from the lens of freshwater situated above the ocean's salt water and within the island. It is the aim of this paper to investigate the process of withdrawal from the lens of freshwater with a view to establishing the critical flow values for withdrawal and the effects of sink location and density differences on these values, and also to determine the effects of relative density differences.Steady solutions are found for the shape of the interface between salt and freshwater beneath a tropical island. A Green_s function approach is used and proves to be much more robust than spectral methods. Computations of the surface...
Electrified BPS giants: BPS configurations on giant gravitons with static electric field
, Article Journal of High Energy Physics ; Volume 2007, Issue 10 , 2007 ; 11266708 (ISSN) ; Sheikh Jabbari, M. M ; Sharif University of Technology
2007
Abstract
We consider D3-brane action in the maximally supersymmetric type IIB plane-wave background. Upon fixing the light-cone gauge, we obtain the light-cone Hamiltonian which is manifestly supersymmetric. The 1/2 BPS solutions of this theory (solutions which preserve 16 supercharges) are either of the form of spherical three branes, the giant gravitons, or zero size point like branes. We then construct specific classes of 1/4 BPS solutions of this theory in which static electric field on the brane is turned on. These solutions are deformations about either of the two 1/2 BPS solutions. In particular, we study in some detail 1/4 BPS configurations with electric dipole on the three sphere giant,...