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Applying Deep Reinforcement Learning for Task Offloading and Resource Allocation in Fog-Based Infrastructures
, M.Sc. Thesis Sharif University of Technology ; Izadi, Mohammad (Supervisor)
Abstract
In cloud computing, serving applications is often done by sending data to data centers and servers. This centralized processing model, especially in the field of the Internet of Things (IoT), where the number of devices is very large and their geographical distribution is significant, brings challenges such as limited bandwidth, high latency, and privacy issues. In this context, fog computing, as an efficient solution, organizes devices in a layered manner from the proximity of users to cloud processing centers. This layered structure allows for the distribution of resources and data processing across different regions of the network, tailored to the needs of users and their proximity to...
Experimental Study on the Effects of Initial Suction and Particle Shape on Consolidation and Shear Behavior of Unsaturated Sandy Soils
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Particle morphology refers to the dimensions, shape, surface texture, roundness, and form of the particles. Morphology has a direct impact on the interaction between soil particles. Friction, particle rearrangement, dilation, and interlocking are influenced by the shape and size of the particles. The extensive impact of morphology on soil properties and behavior necessitates a comprehensive examination by geotechnical engineers to predict the behavior of granular materials accurately. Morphology significantly affects soil behavior under shear, volumetric changes, dilative behavior, shear strength, and soil behavior during consolidation testing, as well as changes in void ratio and...
Improvement in Reinforced Concrete Beam-Column Connections Behavior using Steel Plates
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Ali Reza (Supervisor)
Abstract
Performance of reinforced concrete frames is highly dependent on detailing of the joint connections between its members, such as beams and columns. To have a good structural behavior, joints must show ductile behavior and designed based on the philosophy of strong column-weak beam. In the case of sever lacking ductility, strength or even rigidity of the connections, or having a weak column-strong beam, in the existing structures, there is a need for seismic upgrading of the connection. There are several ways for seismic upgrading of this type of connections.In this research, using steel plates for seismic upgrading of Concrete Beam-Column connections subjected to axial and cyclic loads has...
Applications of Statistical Learning in Dynamic Pricing
, M.Sc. Thesis Sharif University of Technology ; Haji Mir Sadeghi, Mir Omid (Supervisor)
Abstract
In the era of the internet and with the emergence of online stores, the possibility of changing prices for these e-commerce platforms has become simple and virtually cost-free. This allows them to adjust prices optimally in response to environmental and surrounding factors, maximizing their revenue from product sales. This development has led to numerous applications of statistical learning methods, particularly online learning, in these markets. In this thesis, we explore the issue of online pricing from various perspectives. One aspect is that product pricing is based on their features, which can be numerous. This leads us to the use of online learning methods and statistical learning in...
Single-Source Capacitated Multi-Facility Weber Problem - An iterative two phase heuristic algorithm
, Article Computers and Operations Research ; Volume 39, Issue 7 , 2012 , Pages 1465-1476 ; 03050548 (ISSN) ; Torabi, S. A ; Eshghi, K ; Sharif University of Technology
2012
Abstract
Multi-Facility Weber Problem (MFWP), also known as continuous locationallocation problem, entails determining the locations of a predefined number of facilities in a planar space and their related customer allocations. In this paper, we focus on a new variant of the problem known as Single-Source Capacitated MFWP (SSCMFWP). To tackle the problem efficiently and effectively, an iterative two-phase heuristic algorithm is put forward. At the phase I, we aim to determine proper locations for facilities, and during the phase II, assignment of customers to these facilities is pursued. As an alternative solution method, a simulated annealing (SA) algorithm is also proposed for carrying out the...
Mesoporous silica nanoparticles (MCM-41) coated PEGylated chitosan as a pH-Responsive nanocarrier for triggered release of erythromycin [electronic resource]
, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; 2014, Volume 63, Issue 13, Pages 692-697 ; Mazaheri Tehrani, Zahra ; Sharif University of Technology
Abstract
A pH-responsive drug delivery system based on core shell structure of mesoporous silica nanoparticle (MSN) and chitosan-PEG copolymer was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and high-resolution transmission microscope (HR-TEM) techniques. In order to improve compatibility MSN and drug, mesoporous nanosilica was modified by 3-aminopropyl triethoxysilane. The release of erythromycin (a macrolide antibiotic) as a model drug was investigated in two pHs, 7.4 and 5.5
Thermo-mechanical behavior of functionally graded circular sector plates
, Article Acta Mechanica ; Volume 226, Issue 1 , 2014 , Pages 37-54 ; 00015970 ; Nosier, A ; Sharif University of Technology
2014
Abstract
By reformulating the governing equations of the first-order theory into those describing the interior and edge-zone problems of the plate, closed-form solutions are presented for analysis of functionally graded circular sector plates with vertex angle (Formula presented.) whose radial edges are simply supported and subjected to transverse loading and heat conduction through the plate thickness. Various types of clamped, simply supported, and free-edge boundary supports are considered on the circular edge of the plate. The material properties are graded through the plate thickness according to a power-law distribution of the volume fraction of the constituents. The effects of material...
Nonlinear behavior of functionally graded circular plates with various boundary supports under asymmetric thermo-mechanical loading
, Article Composite Structures ; Volume 94, Issue 9 , 2012 , Pages 2834-2850 ; 02638223 (ISSN) ; Nosier, A ; Sharif University of Technology
2012
Abstract
The equilibrium equations of the first-order nonlinear von Karman theory for FG circular plates under asymmetric transverse loading and heat conduction through the plate thickness are reformulated into those describing the interior and edge-zone problems of the plate. A two parameter perturbation technique, in conjunction with Fourier series method is used to obtain analytical solutions for nonlinear behavior of functionally graded circular plates with various clamped and simply-supported boundary conditions. The material properties are graded through the plate thickness according to a power-law distribution of the volume fraction of the constituents. The results are verified with known...
Thermo-mechanical behavior of functionally graded circular sector plates
, Article Acta Mechanica ; Volume 226, Issue 1 , January , 2015 , Pages 37-54 ; 00015970 (ISSN) ; Nosier, A ; Sharif University of Technology
Springer-Verlag Wien
2015
Abstract
By reformulating the governing equations of the first-order theory into those describing the interior and edge-zone problems of the plate, closed-form solutions are presented for analysis of functionally graded circular sector plates with vertex angle (Formula presented.) whose radial edges are simply supported and subjected to transverse loading and heat conduction through the plate thickness. Various types of clamped, simply supported, and free-edge boundary supports are considered on the circular edge of the plate. The material properties are graded through the plate thickness according to a power-law distribution of the volume fraction of the constituents. The effects of material...
On the nonlinear bending and post-buckling behavior of laminated sandwich cylindrical shells with FG or isogrid lattice cores
, Article Acta Mechanica ; 2019 ; 00015970 (ISSN) ; Taati, E ; Sharif University of Technology
Springer-Verlag Wien
2019
Abstract
The nonlinear governing equations of three shell theories (Donnell, Love, and Sanders) with first-order approximation and von Kármán’s geometric nonlinearity for laminated sandwich cylindrical shells with isotropic, functionally graded (FG) or isogrid lattice layers are decoupled. This uncoupling makes it possible to present a semi-analytical solution for the nonlinear bending and post-buckling behavior of short and long doubly simply supported, doubly clamped, and cantilever laminated sandwich cylindrical shells subjected to various types of thermo-mechanical loadings. The results for deflection, stress, critical axial traction, and mode shapes in FG shells are verified with those obtained...
On an extended Kantorovich method for the mechanical behavior of functionally graded solid/annular sector plates with various boundary conditions
, Article Acta Mechanica ; Volume 228, Issue 7 , 2017 , Pages 2655-2674 ; 00015970 (ISSN) ; Khakbaz, A ; Sharif University of Technology
Springer-Verlag Wien
2017
Abstract
Based on the first-order shear deformation plate theory, two approaches within the extended Kantorovich method (EKM) are presented for a bending analysis of functionally graded annular sector plates with arbitrary boundary conditions subjected to both uniform and non-uniform loadings. In the first approach, EKM is applied to the functional of the problem, while in the second one EKM is applied to the weighted integral form of the governing differential equations of the problem as presented by Kerr. In both approaches, the system of ordinary differential equations with variable coefficients in r direction and the set of ordinary differential equations with constant coefficients in θ direction...
On the nonlinear bending and post-buckling behavior of laminated sandwich cylindrical shells with FG or isogrid lattice cores
, Article Acta Mechanica ; 2019 ; 00015970 (ISSN) ; Taati, E ; Sharif University of Technology
Springer-Verlag Wien
2019
Abstract
The nonlinear governing equations of three shell theories (Donnell, Love, and Sanders) with first-order approximation and von Kármán’s geometric nonlinearity for laminated sandwich cylindrical shells with isotropic, functionally graded (FG) or isogrid lattice layers are decoupled. This uncoupling makes it possible to present a semi-analytical solution for the nonlinear bending and post-buckling behavior of short and long doubly simply supported, doubly clamped, and cantilever laminated sandwich cylindrical shells subjected to various types of thermo-mechanical loadings. The results for deflection, stress, critical axial traction, and mode shapes in FG shells are verified with those obtained...
Non-linear thermo-mechanical cylindrical bending of functionally graded plates
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 222, Issue 3 , 2008 , Pages 305-318 ; 09544062 (ISSN) ; Nosier, A ; Sharif University of Technology
2008
Abstract
Based on the first-order non-linear von Karman theory, cylindrical bending of functionally graded (FG) plates subjected to mechanical, thermal, and combined thermo-mechanical loadings are investigated. Analytical solutions are obtained for an FG plate with various clamped and simply-supported boundary conditions. The closed form solutions obtained are very simple to be used in design purposes. The material properties are assumed to vary continuously through the thickness of the plate according to a power-law distribution of the volume fraction of the constituents. The effects of non-linearity, material property, and boundary conditions on various response quantities are studied and...
Time-indexed Mathematical Models for Order Acceptance and Scheduling Problems
, M.Sc. Thesis Sharif University of Technology ; Kianfar, Farhad (Supervisor)
Abstract
Scheduling has been an active area of research for decades. A substantial amount of work has been done to define, classify, and solve scheduling problems. Most of these problems are computationally difficult to solve, and incorporating other decisions into them increases the complexity of these problems. This thesis focuses on order acceptance and scheduling (OAS) problems, and proposes time-indexed mixed integer and linear programming (MILP) models for the first time. An OAS problem can be defined with parameters of processing time, release date, due date, and deadline for each order. There are also a maximum revenue that will be brought by each order and an importance weight of each order....
The Effect of Heat Treatment on Microstructure and Mechanical Properties of Directionally Solidified Nickel-based Superalloy GTD-111
, M.Sc. Thesis Sharif University of Technology ; Varahram, Naser (Supervisor)
Abstract
The Ni-based superalloy GTD-111 possesses excellent hot corrosion resistance, high stability and strength at elevated temperature; accordingly, the alloy is used in manufacturing of the first stage blades of powerful gas turbines. In this study, effect of withdrawal rate from Bridgman furnace and precipitation hardening on the microstructure and microhardness of this superalloy were investigated. To this end, several experiments were carried out under growth rates of 1, 6 and 10 mm/min using Bridgman process under vacuum. Afterwards, the effects of homogenization treatment, partial dissolution with two different cooling rates (air and water) along with aging on the microstructure were...
The Motility of Lipid Vesicles Due to Phase Transition in Transmemerance Proteine
, M.Sc. Thesis Sharif University of Technology ; Jalali, Mir Abbas (Supervisor)
Abstract
Phospholipid vesicles are able to carry drugs or DNA to infected or cancerous cells. The blood flow can carry them to their target positions but their performance will be enhanced if they complete their attack by swimming in final stages of their journey. Vesicles built only by lipid molecules have rotational symmetry and undergo a random motion in their solvents without having a preferred direction. In this project, we break the symmetrical shape of phospholipid vesicles by a cluster of transmembrane proteins. We use a triangulated model of the membrane, apply the method of multi-particle collision dynamics to the motion of solvent particles, and simulate the motility of vesicles for...
Control of Chaotic Waves in Hard Disk Drives
, M.Sc. Thesis Sharif University of Technology ; Jalali, Mir Abbas (Supervisor)
Abstract
Hard disk drives are the main component of computers for permanent data storage. The security of the stored data is related closely to the air gap between the read-write head and the surface of disk. This gap which is created by the aerodynamic force between head and the disk is altered continually by lateral oscillations of disk. In the extreme condition of zero gap and contact between the protective coating layer and subsequently the magnetic material of the disk with the head, the disk will be scratched and damaged. Therefore, the active or passive control of these vibrations has a particular importance in the technology of manufacturing of hard disks. The first step in active control...
A Study of the Phase Diagram of the Hubbard Model Using Modern Numerical Methods
, M.Sc. Thesis Sharif University of Technology ; Vaezi, Mir Abolhassan (Supervisor)
Abstract
The Hubbard model is one of the simplest interacting models in theoretical physics, especially condensed matter physics which despite its simplicity, its solutions are highly nontrivial and intractable. After 5 decades since its introduction, its phase diagram is not fully understood and whether or not, it has a high-temperature superconducting phase. In this thesis, we aim to employ the recent advances in machine learning and GPU programming to accelerate the QMC method. By accelerated QMC methods, we can explore the Hubbard model's phase diagram more efficiently. Using massive parallelization of the GPUs can speed up the measuring process by several times. The self-learning quantum...
Experimental Investigation into the Behaviour of Moment-Resisting Frames under Fire
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
As it is known, one of the dangerous consequences of the earthquake is the possibility of fire. In recent years in our country special attention have been paid to design and retrofit buildings against earthquakes, but have not done to understand the behavior and design concepts of structures against fire. One of the reasons is the lack of information and the absence of a specific standard for design of structures against fire. Since the beam-to-column connections play an important role in the performance of structures, in this study, the behavior of the moment frame with flush end plate was investigated by testing on a small scale structural model (half scale). It is observed that, the test...
Theoretical and Computational Investigation of Quantum Plasmonic Properties of Nanocluster Dimers
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Zahra (Supervisor)
Abstract
In today's era, metal nanoparticles play an important role in technologies emerging from different sciences, such as chemistry, physics, optics, material science, due to their unique characteristics. In the development of nanooptics science, it can be said that metal nanoparticles play an important role. The ability of conductive electrons collective oscillation causes surface charge density fluctuations in nanoparticles, this phenomenon is known as surface plasmons. Surface plasmons are surprisingly coupled with light and cause the significant increase in the intensity of optical fields induced in nanoparticles. Therefore, with the presence of localized surface plasmons or plasmon...