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moftakhar-daryaie-nejad--kobra
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Spillover Effects in Returns and Volatilities to Estimate the Value at Risk of Portfolio, Consist of Gold, Foreign Exchange and Stocks
, M.Sc. Thesis Sharif University of Technology ; Keshavarz Haddad, Gholamreza (Supervisor)
Abstract
Accurate modelling of volatility (or risk) is important in finance, particularly as it relates to the modelling and forecasting of value-at-risk (VaR) thresholds. As financial applications typically deal with a portfolio of assets and risk, there are several multivariate GARCH models which specify the risk of one asset as depending on its own past as well as the past behaviour of other assets. So we mustn't ignore return and volatility spillover effects between different assets in the portfolio for estimating the portfolio value at risk. Many studies in financial economics in recent decades investigate the spillover effects and modelling it. In this research we analyze the importance of...
Supersonic Separation
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor) ; Nouri Borujerdi, Ali (Supervisor)
Abstract
Supersonic separators with neither rotating parts nor chemical process, physically separate particles in a multi-phase flow. In comparison with general separation techniques, which are utilized in industries, specifically this equipment is cheaper, smaller and lighter. Condensation and separation at supersonic velocity is the key to achieve a significant reduction in both capital and operating costs. In this study, a two dimensional de Laval nozzle and few three-dimensional supersonic separator have been modeled. The 3D models modified in shape and dimensions. Impellers were created to form swirl flow. The models were simulated by the use of CFD software ANSYS FLUENT. Diverse inlet pressures...
Orderenergetic graphs
, Article Match ; Volume 84, Issue 2 , 2020 , Pages 325-334 ; Ghahremani, M ; Gutman, I ; Koorepazan Moftakhar, F ; Sharif University of Technology
University of Kragujevac, Faculty of Science
2020
Abstract
A graph is said to be orderenergetic if its energy is equal to its order. It is shown that there are infinitely many connected orderenergetic graphs. Some basic properties of these graphs are established. Several open problems and conjectures are pointed out. © 2020 University of Kragujevac, Faculty of Science. All rights reserved
Improving self-care and health literacy in hemodialysis patients: Using software engineering
, Article Proceedings - 2012 7th International Conference on Computing and Convergence Technology (ICCIT, ICEI and ICACT), ICCCT 2012, 3 December 2012 through 5 December 2012 ; December , 2012 , Pages 317-320 ; 9788994364216 (ISBN) ; Edalat-Nejad, M ; Edalat-Nejad, N ; Sharif University of Technology
2012
Abstract
The use of Computer Science in order to categorize and store information, improve diagnostic and therapeutic procedures, patient education and the training of a skilled labor force, has taken important steps and there are constantly new developments in this area
An algorithm for constructing all supercharacter theories of a finite group
, Article Ars Mathematica Contemporanea ; Volume 18, Issue 1 , 2020 , Pages 149-162 ; Ghanbari Maman, L ; Kavousi, K ; Koorepazan Moftakhar, F ; Sharif University of Technology
Society of Mathematicians, Physicists and Astronomers of Slovenia
2020
Abstract
In 2008, Diaconis and Isaacs introduced the notion of a supercharacter theory of a finite group in which supercharacters replace with irreducible characters and superclasses by conjugacy classes. In this paper, we introduce an algorithm for constructing supercharacter theories of a finite group by which all supercharacter theories of groups containing up to 14 conjugacy classes are calculated. © 2020 Society of Mathematicians, Physicists and Astronomers of Slovenia. All rights reserved
Hypoenergetic and nonhypoenergetic digraphs
, Article Linear Algebra and Its Applications ; Volume 618 , 2021 , Pages 129-143 ; 00243795 (ISSN) ; Das, K. C ; Khalashi Ghezelahmad, S ; Koorepazan Moftakhar, F ; Sharif University of Technology
Elsevier Inc
2021
Abstract
The energy of a graph G, E(G), is the sum of absolute values of the eigenvalues of its adjacency matrix. This concept was extended by Nikiforov to arbitrary complex matrices. Recall that the trace norm of a digraph D is defined as, N(D)=∑i=1nσi, where σ1≥⋯≥σn are the singular values of the adjacency matrix of D. In this paper we would like to present some lower and upper bounds for N(D). For any digraph D it is proved that N(D)≥rank(D) and the equality holds if and only if D is a disjoint union of directed cycles and directed paths. Finally, we present a lower bound on σ1 and N(D) in terms of the size of digraph D. © 2021 Elsevier Inc
Hypoenergetic and nonhypoenergetic digraphs
, Article Linear Algebra and Its Applications ; Volume 618 , 2021 , Pages 129-143 ; 00243795 (ISSN) ; Das, K. C ; Khalashi Ghezelahmad, S ; Koorepazan Moftakhar, F ; Sharif University of Technology
Elsevier Inc
2021
Abstract
The energy of a graph G, E(G), is the sum of absolute values of the eigenvalues of its adjacency matrix. This concept was extended by Nikiforov to arbitrary complex matrices. Recall that the trace norm of a digraph D is defined as, N(D)=∑i=1nσi, where σ1≥⋯≥σn are the singular values of the adjacency matrix of D. In this paper we would like to present some lower and upper bounds for N(D). For any digraph D it is proved that N(D)≥rank(D) and the equality holds if and only if D is a disjoint union of directed cycles and directed paths. Finally, we present a lower bound on σ1 and N(D) in terms of the size of digraph D. © 2021 Elsevier Inc
Energy of graphs containing disjoint cycles
, Article Match ; Volume 86, Issue 3 , 2021 , Pages 543-547 ; 03406253 (ISSN) ; Das, K. C ; Ghahremani, M ; Koorepazan Moftakhar, F ; Raou, E ; Sharif University of Technology
University of Kragujevac, Faculty of Science
2021
Abstract
Let G be a graph. The energy E(G) is the sum of the absolute values of the eigenvalues of the adjacency matrix of G. In [Energy, matching number and odd cycles of graphs, Linear Algebra Appl. 577 (2019) 159{167] it has been proved that for a graph G whose cycles are odd and vertex disjoint, if from each cycle of G, we remove an arbitrary edge to obtain a tree T, then E(G) ≥ E(T). There is a gap in the proof. In this paper, we correct the proof and generalize this result by showing that if G is a graph all of whose cycles are vertex disjoint and the length of each cycle is not 0, modulo 4, then for any spanning tree of G, E(G) ≥ E(T). Finally we give an upper bound on E(G) of a graph G all of...
Energy of graphs containing disjoint cycles
, Article Match ; Volume 86, Issue 3 , 2021 , Pages 543-547 ; 03406253 (ISSN) ; Das, K. C ; Ghahremani, M ; Koorepazan Moftakhar, F ; Raou, E ; Sharif University of Technology
University of Kragujevac, Faculty of Science
2021
Abstract
Let G be a graph. The energy E(G) is the sum of the absolute values of the eigenvalues of the adjacency matrix of G. In [Energy, matching number and odd cycles of graphs, Linear Algebra Appl. 577 (2019) 159{167] it has been proved that for a graph G whose cycles are odd and vertex disjoint, if from each cycle of G, we remove an arbitrary edge to obtain a tree T, then E(G) ≥ E(T). There is a gap in the proof. In this paper, we correct the proof and generalize this result by showing that if G is a graph all of whose cycles are vertex disjoint and the length of each cycle is not 0, modulo 4, then for any spanning tree of G, E(G) ≥ E(T). Finally we give an upper bound on E(G) of a graph G all of...
Introduction of clinical, simulation-based software for medical sciences teachings
, Article Procedia Engineering ; Volume 29 , 2012 , Pages 43-47 ; 18777058 (ISSN) ; Edalat-Nejad, M ; Edalat Nejad, N ; Edalatnejad, M ; Sharif University of Technology
2012
Abstract
Simulation is the gold standard for training in aviation and trauma medicine. Now it is available for diseases diagnosis and treatment. With simulation, clinicians can practice their art in a realistic, consequence free environment, combining both theory and practice in a comprehensive program. Method and materials - In the virtual clinical environment of "VPsoft mentor" software, the practitioner reviews a patient's history, orders laboratory tests and procedures, interprets findings, renders diagnoses, and prescribes medication. Every diagnostic or treatment decision the clinician makes for the patient is analyzed by E-mentor, providing instant feedback.Results - This software have been...
Using three-dimensional finite element analysis for simulation of residual stresses in railway wheels
, Article Engineering Failure Analysis ; Vol. 45, issue , October , 2014 , p. 449-455 ; Sharif University of Technology
2014
Abstract
One of the most important issues in railway wheels is residual stresses. It is desirable to produce less residual stresses when possible and to decrease the remaining residual stresses in the wheels. The objective of this paper is to provide an estimation of the residual stresses in the rail wheel caused by the stress field from heat treatment process of a railway wheel. A three-dimensional nonlinear stress analysis model has been applied to estimate stress fields of the railway mono-block wheel in heat treatment process. After forging or casting, railway wheels are heat-treated to induce the desirable circumferential compressive residual stress in the upper rim. Finite element analysis...
On the minimum energy of regular graphs
, Article Linear Algebra and Its Applications ; Volume 581 , 2019 , Pages 51-71 ; 00243795 (ISSN) ; Akbari, S ; Ghasemian, E ; Ghodrati, A. H ; Hosseinzadeh, M. A ; Koorepazan Moftakhar, F ; Sharif University of Technology
Elsevier Inc
2019
Abstract
The energy of a graph G, E(G), is the sum of absolute values of the eigenvalues of its adjacency matrix. Gutman et al. proved that for every cubic graph of order n, E(G)≥n. Here, we improve this result by showing that if G is a connected subcubic graph of order n≥8, then E(G)≥1.01n. Also, we prove that if G is a traceable subcubic graph of order n≥8, then E(G)>1.1n. Let G be a connected cubic graph of order n≥8, it is shown that E(G)>n+2. It was proved that if G is a connected cubic graph of order n, then E(G)≤1.65n. Also, in this paper we would like to present the best lower bound for the energy of a connected cubic graph. We introduce an infinite family of connected cubic graphs whose for...
Equations of motion of a ring-like robot with a flexible body and creeping-rolling motion
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings ; 2010 , pp. 191-197 ; ISBN: 9780791843833 ; Alasty, A ; Sharif University of Technology
2010
Abstract
The robots that can move on rough terrains are very important especially in Rescue operation, exploration, etc. In this research, a mechanism is introduced for a ring-like robot with a flexible body. This robot is moved by arms which are placed radially and have Reciprocating motion in this direction. By controlling the contraction and the extension of the arms which contact lhe ground, the robot will be forced to move which is called rolling-creeping motion. The robot is stable in stationary state.; also the maximum angle which it can be stable is determined. Considering the speed of contracted arm is the input parameter, the speed of the extended arm for locomotion of the robot has been...
Optimization of platinum extraction by Trioctylphosphine oxide in the presence of alkaline-metal salts
, Article Procedia Engineering, 25 August 2012 through 29 August 2012 ; Volume 42 , August , 2012 , Pages 1302-1312 ; 18777058 (ISSN) ; Kazemeini, M ; Sharif University of Technology
2012
Abstract
Effect of alkaline metal salts on the solvent extraction of platinum from leached spent dehydrogenation catalysts (Pt/Al2O3) in aqua-regia by the Trioctylphosphine oxide (TOPO) has been investigated. Best salting out effect was achieved using KCl as the additive salt in which process upto 90% of Platinum extraction achieved. Response Surface methodology utilized in order to design the experiments, model the extraction process for platinum and aluminum as well as; optimize the whole process. It was shown that solvent extraction of platinum by TOPO was kinetically fast and the needed equilibrium time for it was less than 30 seconds. In the present study, proposed models for platinum and...
A novel overlap-based logic cell: An efficient implementation of flip-flops with embedded logic
, Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume 18, Issue 2 , 2010 , Pages 222-231 ; 10638210 (ISSN) ; Maymandi Nejad, M ; Sharif University of Technology
2010
Abstract
This paper presents several efficient architectures of dynamic/static edge-triggered flip-flops with a compact embedded logic. The proposed structure, which benefits from the overlap period, fixes most of the drawbacks of the dynamic logic family. The design issues of setting the appropriate overlap period for this architecture are explained. The proposed overlap-based approach is compared with several state-of-the-art dynamic/static logic styles in implementing a 4-bit shift register and an odd-even sort coprocessor using different CMOS technologies. The simulation results showed that the overlap-based logic cells become much more efficient when the complexity of their embedded logic...
Significant enhancement in the efficiency of photoconductive antennas using a hybrid graphene molybdenum disulphide structure
, Article Journal of Nanophotonics ; Volume 10, Issue 3 , 2016 ; 19342608 (ISSN) ; Safian, R ; Sharif University of Technology
SPIE
2016
Abstract
We propose a hybrid graphene molybdenum disulphide-based photoconductive antenna to overcome the restrictions of metallic photoconductive antennas and graphene-based photoconductive antennas, simultaneously. The structure is composed of a hybrid graphene-MoS2 strip as the antenna deposited on a low-temperature gallium arsenide substrate. A full-wave electromagnetic solver, namely, high frequency structural simulator (HFSS) is used to analyze the whole structure. It is shown that the proposed photoconductive antenna provides us with not only high input impedance and reconfigurability but also high values of matching efficiency and radiation efficiency. The impact of increasing MoS2 layers on...
A graphene-based THz ring resonator for label-free sensing
, Article IEEE Sensors Journal ; Volume 16, Issue 11 , 2016 , Pages 4338-4344 ; 1530437X (ISSN) ; Safian, R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper, we report on a novel resonant THz sensor for label-free analysis. The structure consists of a silicon nitride dielectric ring resonator vertically coupled to a thin layer of graphene strip ring resonator on top. The cladding is assumed to be porous alumina on the top of the graphene strip, which enhances the interaction of the surface plasmon wave and the target molecules. Finite difference time domain analysis is used to systematically design the structure and to investigate the performance of the sensor. Our simulations show that the proposed structure has larger refractive index sensitivity and lower intrinsic quality factor with respect to the similar optical structure. It...
Investigation and modeling of the thermal conductivity of PP/clay nanocomposites and PP/MWCNT nanocomposites
, Article E-Polymers ; Dec , 2010 ; 16187229 (ISSN) ; Golzary, A ; Sharif University of Technology
2010
Abstract
In this study, polypropylene/clay nanocomposites were prepared by melt blending method and their thermal conductivity and the thermal conductivity of polypropylene/multi-wall carbon nanotube (MWCNT) nanocomposites were investigated and modeled. It is found that the thermal conductivity of the PP/Clay and PP/MWCNT nanocomposites is increased with increasing temperature. The thermal conductivity of the nanocomposites is improved due to incorporation of nanoclay and MWCNT compared with pure PP matrix
Toward a collaborative method for knowledge management of software architectural decisions based on trust
, Article 12th International Conference on Fuzzy Systems and Knowledge Discovery, 15 August 2015 through 17 August 2015 ; 2015 , Pages 828-834 ; 9781467376822 (ISBN) ; Moaven, S ; Habibi, J ; Alidousti, R
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Design and implementation of Architecture is a knowledge-driven process. Evaluation and verification the knowledge, in order to ensure its quality, have important role in improving overall design process. Furthermore, Architectural decision making is a complex and multi-criteria decision making problem in which multiple stakeholders make decisions from their perspectives causing overlaps and conflicts in the adopted decisions. Therefore, the requirement for strategies to manage these issues and also to improve coordination and cooperation among the various stakeholders to improve the overall process design is necessary. In this regard, there have been several activities that focus on...
Spatial integration by a dielectric slab and its planar graphene-based counterpart
, Article Optics Letters ; Volume 42, Issue 10 , 2017 , Pages 1954-1957 ; 01469592 (ISSN) ; Khavasi, A ; Sharif University of Technology
2017
Abstract
In this contribution a new approach to perform spatial integration is presented using a dielectric slab. Our approach is indeed based on the fact that the transmission coefficient of a simple dielectric slab at its mode excitation angle matches the Fourier-Green's function of first-order integration. Inspired by the mentioned dielectric-based integrator, we further demonstrate its graphene-based counterpart. The latter is not only reconfigurable but also highly miniaturized in contrast to the previously reported designs [Opt. Commun. 338, 457 (2015)]. Such integrators have the potential to be used in ultrafast analog computation and signal processing. © 2017 Optical Society of America