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A study of the required sustainability-driven institutional and behavioural mechanisms to tackle the anticipated implications of agricultural water price shocks: a system dynamics approach
, Article Scientific Reports ; Volume 13, Issue 1 , 2023 ; 20452322 (ISSN) ; Razavi, V ; Zahedi, S ; Momeni, F ; Behzadian, K ; Dolatabadi, N ; Sharif University of Technology
Nature Research
2023
Abstract
Economic policies for managing agricultural water use are often complicated by the challenge of using water prices as an efficient economic tool when other non-economic concerns are involved in the decision-making process. This study aims to analyse the impact of water pricing policies on preserving agricultural water resources in Iran. This study applies a system dynamics approach to simulate the system performance and behaviour of stakeholders and the economic implications. Our finding shows that water pricing policies will likely fail due to low water price elasticity and if there are lack of institutional and physical infrastructure, alternative professions, manufacturing technology,...
Predictive equations for drift ratio and damage assessment of RC shear walls using surface crack patterns
, Article Engineering Structures ; Volume 190 , 2019 , Pages 410-421 ; 01410296 (ISSN) ; Dolatshahi, K. M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
The purpose of this paper is to quantify the extent of damage of rectangular reinforced concrete shear walls after an earthquake using surface crack patterns. One of the most important tasks after an earthquake is to assess the safety and classify the performance level of buildings. This assessment is usually performed by visual inspection that is prone to significant errors. In this research, an extensive database on the images of damaged rectangular reinforced concrete shear walls is collected from the literature. This database includes more than 200 images from experimental quasi-static cyclic tests. Using the concept of fractal geometry, several probabilistic models are developed by...
Hot deformation behavior of Fe-29Ni-17Co alloy
, Article Transactions of Nonferrous Metals Society of China (English Edition) ; Volume 23, Issue 11 , 2013 , Pages 3271-3279 ; 10036326 (ISSN) ; Abbasi, S. M ; Taheri, A. K ; Momeni, A ; Sharif University of Technology
2013
Abstract
Hot compression tests were carried out on a Fe-29Ni-17Co alloy in the temperature range of 900 °C to 1200 °C and at strain rates of 0.001-1 s-1. Dynamic recrystallization was found responsible for flow softening during hot compression. The flow behavior was successfully analyzed by the hyperbolic sine equation and the corresponding material constants A, n and α were determined. The value of apparent activation energy was determined as 423 kJ/mol. The peak and steady state strains showed simple power-law dependence on the Zener-Hollomon parameter. The dynamic recrystallization kinetics was analyzed using Avrami equation and the corresponding exponent was determined to be about 2.7. This...
Comparative analysis of agricultural water pricing between Azarbaijan Provinces in Iran and the state of California in the US: A hydro-economic approach
, Article Agricultural Water Management ; Volume 223 , 2019 ; 03783774 (ISSN) ; Zakeri, Z ; Esfandiari, M ; Behzadian, K ; Zahedi, S ; Razavi, V ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Iranian water authority has recently announced that one of the effective ways to avoid unprecedented high water consumption in Iran's agriculture sector is to increase water price. This paper analyzes the feasibility of this policy by using a hydro-economic approach with the aim to consider the role of water pricing in agricultural water management. Such an analysis was conducted through comparing price of water consumed for producing selected agricultural crops (i.e. wheat, sugar beets, onion, tomato, barley, potato, corn, alfalfa hay and watermelon) in a case study on two provinces (East Azarbaijan and West Azarbaijan) in Iran to that in the state of California (CA) in the USA. According...
High-dimensional data analytics for sparse recovery of guided-waves dispersion curves using b-splines
, Article Structural Health Monitoring 2023: Designing SHM for Sustainability, Maintainability, and Reliability - Proceedings of the 14th International Workshop on Structural Health Monitoring ; 2023 , Pages 796-803 ; 978-160595693-0 (ISBN) ; Jeddi, M ; Ebrahimkhanlou, A ; Farhangdoust S ; Guemes A ; Chang F. K ; Sharif University of Technology
DEStech Publications
2023
Abstract
This research presents a technique to recover the dispersion curves of guided-waves by utilizing the inherent sparsity of these signals in the frequency-wavenumber domain. The proposed methodology is a data-driven approach that combines physics-based knowledge with high-dimensional analysis to obtain the dispersion curves of the medium from experimental signals. Initially, a sparse two-dimensional dispersion matrix is constructed using sparse wavenumber analysis. Then, B-splines are fitted to non-zero elements of this matrix to establish an initial estimate of the dispersion curve parameters. These parameters are further optimized using the quasi-Newton algorithm to improve the accuracy of...
Introducing structural approximation method for modeling nanostructures
, Article Journal of Computational and Theoretical Nanoscience ; Vol. 7, Issue 2 , 2010 , p. 423-428 ; ISSN: 15461955 ; Alasty, A ; Sharif University of Technology
2010
Abstract
In this work a new method for analyzing nanostructured materials has been proposed to accelerate the simulations for solid crystalline materials. The proposed Structural Approximation Method (SAM) is based on Molecular Dynamics (MD) and the accuracy of the results can also be improved in a systematic manner by sacrificing the simulation speed. In this method a virtual material is used instead of the real one, which has less number of atoms and therefore fewer degrees of freedom, compared to the real material. The number of differential equations that must be integrated in order to specify the state of the system will decrease significantly, and the simulation speed increases. To generalize...
Improving a computer networks course using the Partov simulation engine
, Article IEEE Transactions on Education ; Volume 55, Issue 3 , 2012 , Pages 436-443 ; 00189359 (ISSN) ; Kharrazi, M ; Sharif University of Technology
2012
Abstract
Computer networks courses are hard to teach as there are many details in the protocols and techniques involved that are difficult to grasp. Employing programming assignments as part of the course helps students to obtain a better understanding and gain further insight into the theoretical lectures. In this paper, the Partov simulation engine and experience using this engine in a computer networks course are discussed. Since 2009, various programming assignments based on the Partov system have been set to help students in their learning process. Student feedback has been very good; this has been quantified in two surveys in which a majority of students expressed their satisfaction with this...
Partov: A network simulation and emulation tool
, Article Journal of Simulation ; Volume 10, Issue 4 , 2016 , Pages 237-250 ; 17477778 (ISSN) ; Kharrazi, M ; Sharif University of Technology
Palgrave Macmillan Ltd
2016
Abstract
Network protocol design and evaluation requires either full implementation of the considered protocol and evaluation in a real network, or a simulation based on a model. There is also a middle approach in which both simulation and emulation are used to evaluate a protocol. In this article the Partov engine, which provides both simulation and emulation capabilities simultaneously, is presented. Partov benefits from a layered and platform-independent architecture. As a pure simulator, it provides an extensible plugin-based platform that can be configured to perform both real-time and non-real-time discrete-event simulations. It also acts as an emulator, making interaction with real networks...
Introducing structural approximation method for modeling nanostructures
, Article Journal of Computational and Theoretical Nanoscience ; Volume 7, Issue 2 , February , 2010 , Pages 423-428 ; 15461955 (ISSN) ; Alasty, A ; Sharif University of Technology
2010
Abstract
In this work a new method for analyzing nanostructured materials has been proposed to accelerate the simulations for solid crystalline materials. The proposed Structural Approximation Method (SAM) is based on Molecular Dynamics (MD) and the accuracy of the results can also be improved in a systematic manner by sacrificing the simulation speed. In this method a virtual material is used instead of the real one, which has less number of atoms and therefore fewer degrees of freedom, compared to the real material. The number of differential equations that must be integrated in order to specify the state of the system will decrease significantly, and the simulation speed increases. To generalize...
Exact solution for the massless cylindrically symmetric scalar field in general relativity, with cosmological constant
, Article International Journal of Modern Physics A ; Volume 24, Issue 31 , 2009 , Pages 5991-6000 ; 0217751X (ISSN) ; Miraghaei, H ; Sharif University of Technology
2009
Abstract
In this paper we present a new exact solution for scalar field with cosmological constant in cylindrical symmetry Associated cosmological models including a model that describes a cyclic universe are discussed
LDMBL: An architecture for reducing code duplication in heavyweight binary instrumentations
, Article Software - Practice and Experience ; Volume 48, Issue 9 , 2018 , Pages 1642-1659 ; 00380644 (ISSN) ; Kharrazi, M ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
Emergence of instrumentation frameworks has vastly contributed to the software engineering practices. As the instrumentation use cases become more complex, complexity of instrumenting programs also increases, leading to a higher risk of software defects, increased development time, and decreased maintainability. In security applications such as symbolic execution and taint analysis, which need to instrument a large number of instruction types, this complexity is prominent. This paper presents an architecture based on the Pin binary instrumentation framework to abstract the low-level OS and hardware-dependent implementation details, facilitate code reuse in heavyweight instrumentation use...
Designing an intelligent controller for a molecular valve
, Article 2008 Proceedings of the ASME - 2nd International Conference on Integration and Commercialization of Micro and Nanosystems, MicroNano 2008, 3 June 2008 through 5 June 2008, Kowloon ; 2008 , Pages 195-201 ; 0791842940 (ISBN); 9780791842942 (ISBN) ; Alasty, A ; Sharif University of Technology
2008
Abstract
Too much effort has been done for manipulating individual atoms, using nano-manipulators and Scanning Tunneling Microscopes (STM). On the other hand, characterization and manipulation of nano-flows is of great concern. In the current work a molecular valve has been considered, which is made up of six atoms placed on the circumstance of a circle. A fuzzy controller has been designed for controlling the diameter of this molecular valve. The designed fuzzy controller used singleton fuzzifier, Mamdani inference engine, center average defuzzifier and exponential membership functions. A model based on the classical Molecular Dynamics (MD) is used for modeling the nano-system and passing the states...
Stress distribtuion on open-ended carbon nanotubes
, Article 2008 Proceedings of the ASME - 2nd International Conference on Integration and Commercialization of Micro and Nanosystems, MicroNano 2008, 3 June 2008 through 5 June 2008, Kowloon ; 2008 , Pages 343-351 ; 0791842940 (ISBN); 9780791842942 (ISBN) ; Alasty, A ; Sharif University of Technology
2008
Abstract
The stress distribution on open-ended Carbon Nanotubes (CNTs) embedded in a composite material is considered in this work and an analytical solution for the stress distribution has been obtained. The effects of CNT's thickness and CNT's length on the distribution of stress have been investigated. To find the governing relations, continuity equations of the axisymmetric problem in cylindrical coordinate (r,o,z) are used. Under some assumptions, the governing equations are solved and by using constitutive equations and applying the boundary conditions, an equation which relates the stress applied to the representative volume element with the stress distribution on the CNT, has been found. The...
Pure coupled mode analysis of diffraction by isotropic transmission volume gratings
, Article IEEE Transactions on Antennas and Propagation ; Volume 52, Issue 12 , 2004 , Pages 3304-3311 ; 0018926X (ISSN) ; Rashidian, B ; Sharif University of Technology
2004
Abstract
The idea of pure coupled mode approach is extended to the analysis of volume grating structures. In this approach, diffraction orders inside the grating are expanded over TE and TM components and unperturbed wavevectors are used instead of Floquet wavevectors of conventional coupled wave approach. Coupling between these orders are considered to model the diffraction. Three-dimensional grating structures are analyzed, and comparisons with rigorous coupled wave analysis are made to verify the accuracy and determine the range of applicability of the proposed method. © 2004 IEEE
Improved coupled wave analysis of two-dimensional planar multiple gratings
, Article IEEE Transactions on Antennas and Propagation ; Volume 52, Issue 1 , 2004 , Pages 165-171 ; 0018926X (ISSN) ; Rashidian, B ; Sharif University of Technology
2004
Abstract
An improved coupled wave approach is presented for the analysis of diffraction behavior of a two-dimensional spatially periodic or almost periodic dielectric layer illuminated by TE polarized plane waves. This method applies to any simultaneous composition of arbitrarily modulated planar transmission gratings with any permittivity in neighboring regions. Two major improvements have been made. In the first part, the eigenvalues and eigenvectors of coupled wave system of equations are first-order corrected to reduce the inherent errors generated by neglecting second-order derivatives. In the second part, a scattering matrix method is used to model the effect of boundaries. Using this method,...
A Botnet Detection Technique
, M.Sc. Thesis Sharif University of Technology ; Kharrazi, Mehdi (Supervisor)
Abstract
A set of infected computers which are coordinated in some manner by one’s willingness and can perform malicious activities and provide threats in the cyberspace forms a network of bots, namely botnet. Botnet threats are more important and significant than other malwares due to their huge scale. A lot of computers coming together in a network obeying one’s commands allows their controller to conduct, for example, DoS attacks larger than ever seen incidents. This thesis, introduces botnets, their various threats, and an effective technique for detecting them. For this reason, different probable states of bots will be studied and modeled as a coherent bot life-cycle. The bot life-cycle allows...
Software De-Obfuscation and its Applications to Malware Analysis
, Ph.D. Dissertation Sharif University of Technology ; Kharrazi, Mehdi (Supervisor)
Abstract
Obfuscation transformations complicate a software and make it incomprehensible via syntactical changes. This provides high incentive for malware authors to employ different obfuscation techniques. The practical nature of this problem and lack of common definitions in this area have limited the encountering fronts. Whenever a new obfuscation method becomes known in the wild, ad-hoc deobfuscation solutions follow it, trying to recognize it in details and reverse it step by step. As more obfuscation transformations become readily available for malware developers, this approach becomes more costly and impractical. This rises the perceived need for automated deobfuscation. For example, the...
Reciprocal metasurfaces for on-axis reflective optical computing
, Article IEEE Transactions on Antennas and Propagation ; Volume 69, Issue 11 , 2021 , Pages 7709-7719 ; 0018926X (ISSN) ; Rajabalipanah, H ; Rahmanzadeh, M ; Abdolali, A ; Achouri, K ; Asadchy, V. S ; Fleury, R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Analog computing has emerged as a promising candidate for real-time and parallel continuous data processing. This article presents a reciprocal way for realizing asymmetric optical transfer functions (OTFs) in the reflection side of the on-axis processing channels. It is rigorously demonstrated that the presence of cross-polarization exciting normal polarizabilities (CPENPs) of a reciprocal metasurface circumvents the famous challenge of Green's function approach in implementation of on-axis reflective optical signal processing while providing dual computing channels under orthogonal polarizations. Following a comprehensive theoretical discussion and as a proof of concept, an all-dielectric...
Numerical and experimental analysis of drug inhalation in realistic human upper airway model
, Article Pharmaceuticals ; Volume 16, Issue 3 , 2023 ; 14248247 (ISSN) ; Babamiri, A ; Biglarian, M ; Ramiar, A ; Tabe, R ; Inthavong, K ; Farnoud, A ; Sharif University of Technology
MDPI
2023
Abstract
The demand for a more efficient and targeted method for intranasal drug delivery has led to sophisticated device design, delivery methods, and aerosol properties. Due to the complex nasal geometry and measurement limitations, numerical modeling is an appropriate approach to simulate the airflow, aerosol dispersion, and deposition for the initial assessment of novel methodologies for better drug delivery. In this study, a CT-based, 3D-printed model of a realistic nasal airway was reconstructed, and airflow pressure, velocity, turbulent kinetic energy (TKE), and aerosol deposition patterns were simultaneously investigated. Different inhalation flowrates (5, 10, 15, 30, and 45 L/min) and...
A study on a grade-one type of hypo-elastic models
, Article ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis, ESDA 2014 ; Vol. 1 , 2014 ; Asghari, M ; Sharif University of Technology
2014
Abstract
In Hypo-elastic constitutive models an objective rate of the Cauchy stress tensor is expressed in terms of the current state of the stress and the deformation rate tensor D in a way that the dependency on the latter is a homogeneously linear one. In this work, a type of grade-one hypo-elastic models (i.e. models with linear dependency of the hypo-elasticity tensor on the stress) is considered for isotropic materials based on the objective corotational rates of stress. A positive real parameter denoted by n is involved in the considered type. Different values can be selected for this parameter, each selection leads to a specific model within the class of grade-one hypo-elasticity. The spin of...