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Incremental Learning Approach in Spam Detection
, M.Sc. Thesis Sharif University of Technology ; Beygi, Hamid (Supervisor)
Abstract
Studies show that a large proportion of sent emails are spam. Spam is one of the major problems of e-mail users that result in wasting time and cost. To overcome this problem different ways are used, one of the best ways is detecting spam based on their contents. Separating legitimate e-mails and spam within their contents can be categorized as text classification. So machine-learning approaches are extremely applied in text classification, that machine-learning algorithms can be used for spam classification. However, in the majority of these algorithms, training phase is in a batch. Whereas using incremental learning algorithms is preferred in many applications, especially spam detections....
Tearing energy of an annealed bilayer sheet through multiple and single tensile tests
, Article Materials Science and Engineering A ; Volume 528, Issue 29-30 , November , 2011 , Pages 8800-8803 ; 09215093 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2011
Abstract
Tearing energies of annealed Al-steel bilayer sheets are investigated through multiple and single tensile tests. Total tearing energy of two layers determined separately by single tensile test is equal to tearing energy of bilayer sheet. It means that the bond between two layers has no effect on tearing energy
Energy absorption mechanism of Alsteel bilayer sheets produced by cold roll welding during wedge tearing
, Article International Journal of Mechanical Sciences ; Volume 52, Issue 12 , December , 2010 , Pages 1613-1619 ; 00207403 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2010
Abstract
The behavior of Alsteel bilayer sheets produced by cold roll welding is investigated through the wedge tearing process. It is observed that through tearing the energy absorbed by cold roll welded bilayer sheets is larger than that of non-welded ones, even though all parameters are identical. Also bilayer sheets with low bond strength have the same energy absorbed by non-welded bilayer sheets. By investigating all contributing mechanisms in tearing and mechanical properties of composite layers and developing theoretical equations, it is concluded that bending of sheets through wedge tearing plays a major role in difference of energy absorbed by welded and non-welded bilayer sheets. Moreover,...
The effects of annealing phenomena on the energy absorption of roll-bonded Al-steel sheets during wedge tearing
, Article Materials Science and Engineering A ; Volume 527, Issue 27-28 , 2010 , Pages 7329-7333 ; 09215093 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2010
Abstract
The purpose of this paper is to investigate the effects of annealing phenomena on the energy absorption of Al-steel bilayer sheets, bonded by cold rolling, through wedge tearing. Tearing by wedge is a dissipating energy system that includes three components: cutting, friction and plastic deformation due to bending. In order to find the bonding and annealing effects on energy absorption, the non-bonded bilayer sheets are prepared in the same condition of bonded ones. The results show that energy absorption of bonded sheets is larger than that of non-bonded ones. This is due to different plastic bending moment of bonded and non-bonded bilayer sheets. Whenever the bond is improved by heat...
Microstructural evolution and fracture behavior of friction-stir-welded Al-Cu laminated composites
, Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Vol. 45, issue. 1 , 2014 , pp. 361-370 ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
2014
Abstract
In this study, we attempt to characterize the microstructural evolution during friction stir butt welding of Al-Cu-laminated composites and its effect on the fracture behavior of the joint. Emphasis is on the material flow and particle distribution in the stir zone. For this purpose, optical microscopy and scanning electron microscopy (SEM) images, energy-dispersive spectroscopy EDS and XRD analyses, hardness measurements, and tensile tests are carried out on the joints. It is shown that intermetallic compounds exist in lamellas of banding structure formed in the advancing side of the welds. In samples welded from the Cu side, the banding structure in the advancing side and the hook...
Butt joining of Al-Cu bilayer sheet through friction stir welding
, Article Transactions of Nonferrous Metals Society of China (English Edition) ; Volume 22, Issue 12 , 2012 , Pages 2925-2929 ; 10036326 (ISSN) ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
2012
Abstract
Butt joining of Al-Cu bilayer sheet produced by cold roll bonding was studied through friction stir welding (FSW). A defect free joint was obtained. Flow patterns and mixing of two layers during FSW were investigated. Microstructural investigations and hardness profile measurements were carried out. It is shown that material flow in stir zone leads to the formation of banding structure in Cu layer at advancing side. Traces of Al particles along with Al-Cu intermetallic compounds exist in the fined grain region of this banding structure which leads to higher hardness values
Impulsive noise removal from images using sparse representation and optimization methods
, Article 10th International Conference on Information Sciences, Signal Processing and their Applications, ISSPA 2010, 10 May 2010 through 13 May 2010 ; May , 2010 , Pages 480-483 ; 9781424471676 (ISBN) ; Kafashan, M ; Marvasti, F ; Sharif University of Technology
2010
Abstract
In this paper, we propose a new method for impulsive noise removal from images. It uses the sparsity of natural images when they are expanded by mean of a good learned dictionary. The zeros in sparse domain give us an idea to reconstruct the pixels that are corrupted by random-value impulse noises. This idea comes from this reality that noisy image in sparse domain of original image will not have a sparse representation as much as original image sparsity. In this method we assume that the proper dictionary to achieve image in sparse domain is available
Driving Behavior Estimation with Smartphone Data
, M.Sc. Thesis Sharif University of Technology ; Samimi, Amir (Supervisor)
Abstract
Identifying driving behaviors and building an efficient and accurate driving behavior recognition model is of paramount importance for improving driving safety. Nowadays, with the ubiquity of smartphone sensors, many researchers are using smartphone sensory data to create models which forecast driving behaviors. This research introduces a logit model that predicts nine types of driving events using accelerometer and gyroscope sensors with an accuracy of 76 percent
Semisolid joining of aluminum A356 alloy by partial remelting and mechanical stirring
, Article Transactions of Nonferrous Metals Society of China (English Edition) ; Volume 20, Issue 9 , September , 2010 , Pages 1792-1798 ; 10036326 (ISSN) ; Aashuri, H ; Kokabi, A ; Beygi, R ; Sharif University of Technology
2010
Abstract
A method to reach the globular weld structure of A356 aluminum alloy using stirring the localized semisolid zone during butt-joining is developed. Since the heat conductivity of this alloy is very high, the accurate controlling of temperature during joining must be considered. A gas heating system was used to heat up the nitrogen gas up to the required temperature. A dried and free oxygen gas was prepared when a stream of nitrogen gas could pass closely around a hot element. Hot and pure nitrogen gas flow through a precise ceramic nozzle was used to create a localized semisolid pool. At this stage a fine stirrer was introduced into the weld seam in order to mix the two sides into a single...
DM Water Plant Sedimentation as a Cheap and Waste Source of Catalyst for Biodiesel Production
, Article International Journal of Chemical Reactor Engineering ; Volume 14, Issue 1 , 2016 , Pages 113-124 ; 15426580 (ISSN) ; Mohadesi, M ; Hosseini, S ; Davood Beygi, Y ; Moradi, R ; Sharif University of Technology
Walter de Gruyter GmbH
2016
Abstract
Transesterification reaction was performed in the presence of soybean oil, methanol, and Demineralized water plant sedimentation catalyst at 60°C for 8 h in this study. Central composite design method was used to study the effect of catalyst concentration and methanol to oil molar ratio on purity and yield of produced biodiesel. The results showed catalyst concentration of 9.08 wt% and methanol to oil molar ratio of 22.49 as the optimum condition in which the values of purity and yield of the produced biodiesel in the second-order models were 99.89% and 81.83%, respectively. Experiments are in good agreement with the mentioned values as corresponded values are 99.95% and 86.68%,...
Fracture properties of steel fiber reinforced high strength concrete using work of fracture and size effect methods
, Article Construction and Building Materials ; Volume 142 , 2017 , Pages 482-489 ; 09500618 (ISSN) ; Golsorkhtabar, H ; Beygi, M. H. A ; Gholamitabar, M ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
This paper deals with investigation of fracture behavior of steel fiber reinforced high strength concrete (SFRHSC) and compare it to plain high strength concrete (HSC). Based on an experimental program, a series of three point bending tests were carried out on 54 notched beams, as recommended by RILEM. The fracture parameters were measured by two methods: work of fracture method (WFM) and size effect method (SEM). Then the fracture parameters obtained from these two methods were compared. The results showed that with increase of steel fibers, fracture energy of GF in WFM and Gf in SEM increase but this increase in work of fracture method is more significant. The effective size of the process...
Experimental and analytical model analysis of Babolsar's steel arch bridge
, Article 3rd International Conference on Bridge Maintenance, Safety and Management - Bridge Maintenance, Safety, Management, Life-Cycle Performance and Cost, Porto, 16 July 2006 through 19 July 2006 ; 2006 , Pages 235-237 ; 0415403154 (ISBN); 9780415403153 (ISBN) ; Kazemi, M. T ; Lark, B ; Tabrizian, Z ; Sharif University of Technology
Taylor and Francis/ Balkema
2006
Abstract
The paper presents the experimental and analytical model analysis of a steel-girder arch bridge. The field test is carried out by ambient vibration testing under traffic excitations. Both the peak picking method in the frequency domain and the stochastic subspace identification method in the time domain are used for the output-only model identification. A good agreement in identified frequencies has been found between the two methods. It is further demonstrated that the stochastic subspace method provides better mode shapes. The three-dimensional finite element models are constructed and an analytical model analysis is then performed to generate natural frequencies and mode shapes in the...
Effect of Friction Stir Welding on the Micro-Structure and Mechanical Properties of Al-Cu Bilayer Sheets Produced by Roll Welding
, Ph.D. Dissertation Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor) ; Kazeminezhad, Mohsen (Supervisor)
Abstract
Nowadays, bilayer sheets are increasingly used in various industries due to high mechanical properties, high corrosion resistance and low weight. Hence, it seems important to investigate welding of these materials. The main object of this study is to investigate mechanical properties and microstructure of friction stir butt welded Al-Cu bilayer sheets. For this purpose, tensile tests, microhardness measurements, metallographic images, SEM, EDS and XRD analyses have been carried out from the joints. The results show that contact condition between the shoulder and bilayer material (slipping or sticking), plays an important role in material flow during welding and weld quality. Also the...
Friction stir butt welding of Al-Cu bilayer laminated composites: analysis of force, torque, and temperature
, Article International Journal of Advanced Manufacturing Technology ; Volume 88, Issue 1-4 , 2017 , Pages 393-400 ; 02683768 (ISSN) ; Kazeminezhad, M ; Zarezadeh Mehrizi, M ; Eisaabadi, B. G ; Loureiro, A ; Sharif University of Technology
2017
Abstract
The effect of the layer in contact with tool (Al or Cu) and the depth of plunge on friction stir butt welding of Al-Cu bilayer laminated composites produced by cold roll welding were studied. The measurement of weld cross sections and variations of the axial load and torque during welding process showed that material flow is influenced by the material which is in contact with the shoulder. Being Al layer in contact with the shoulder led to higher force and torque during welding, and a defect-free weld could be obtained in this manner. By welding from Cu side, a higher plunge depth was needed to develop enough force and torque and thereby a defect-free weld. The amount of material swept by...
The effect of aging on the fracture characteristics and ductility of self-compacting concrete
, Article Materials and Design ; Volume 55 , March 2014 , Pages 937-948 ; Kazemi, M. T ; Nikbin, I. M ; Vaseghi Amiri, J ; Sharif University of Technology
March 2014
Abstract
Good knowledge of fracture parameters and cracking behavior of self-compacting concrete (SCC) from early ages until the SCC becomes mature plays an important role in design of SCC structure and also in evaluation of durability and consequently prevention of damage. In this paper, variation of fracture parameters and corresponding ductility behavior of SCC at different ages (e.g. 3days, 7days, 28days and 90days) for SCC mixes with w/c ratios of 0.45 and 0.65 have been experimentally studied. To do so, three-point bending tests were carried out on 120 notched beams. Then, size effect method (SEM) and work of fracture method (WFM) were applied to interpret the results. The results of analyses...
The effect of water to cement ratio on fracture parameters and brittleness of self-compacting concrete
, Article Materials and Design ; Volume 50 , 2013 , Pages 267-276 ; 02613069 (ISSN) ; Kazemi, M. T ; Nikbin, I. M ; Amiri, J. V ; Sharif University of Technology
Elsevier Ltd
2013
Abstract
The paper describes an experimental research on fracture characteristics of self-compacting concrete (SCC). Three point bending tests conducted on 154 notched beams with different water to cement (w/c) ratios. The specimens were made from mixes with various w/c ratios from 0.7 to 0.35. For all mixes, common fracture parameters were determined using two different methods, the work-of-fracture method (WFM) and the size effect method (SEM). Test results showed that with decrease of w/c ratio from 0.7 to 0.35 in SCC: (a) the fracture toughness increases linearly: (b) the brittleness number is approximately doubled: (c) the effective size of the process zone cf in SEM and the characteristic...
Optimizing Transmisson from Distant Wind Farms
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Hamid (Supervisor)
Abstract
Wind power is site dependent and is by nature partially dispatchable. Furthermore, good wind sites are far from grid. Due to these problems, and along with the existing limitations in the transmission networks, a comprehensive analysis over an extended time is needed to properly explore all potential wind sites for wind capacity allocation. This problem is computationally expensive and decomposition methods are required to break down this problem. Here Benders decomposition approach is used, which is a popular technique for solving large-scale problems, to decompose the original problem into a master and a subproblem. The master problem is a linear problem, which allocates wind capacity to...
Influence of tool geometry and contact condition on friction stir welding of Al-Cu laminated composites
, Article Advanced Materials Research ; Vol. 856 , 2014 , pp. 16-21 ; ISSN: 10226680 ; Kazeminezhad, M ; Kokabi, A. H ; Alvani, S. M. J ; Verdera, D ; Loureiro, A ; Sharif University of Technology
2014
Abstract
In this study friction stir welding of Al-Cu laminated composites were carried out by two different tool geometries. Welding procedure was carried out from both sides of Al and Cu. Analyzing cross section of welds showed that different contact conditions between shoulder and material, offers different material flow behavior which is dependent on the tool geometry. SEM analyses showed that mixing of materials in nugget region is more pronounced in the advancing side. Also XRD results indicated that welding from Cu side, leads to intermetallic formation in mixed regions
Identification of the Set of Single Nucleotide Variants in Genome Responsible for the Differentiation of Expression of Genes
, M.Sc. Thesis Sharif University of Technology ; Rabiee, Hamid Reza (Supervisor) ; Beigi, Hamid (Supervisor)
Abstract
Single nucleotide polymorphs, There are changes caused by a mutation in a nucleotide in the Dena sequence. Mononucleotide polymorphisms are the most common type of genetic variation. Some of these changes have little or no effect on cells, while others cause significant changes in the expression of cell genes that can lead to disease or resistance to certain diseases. Because of the importance of these changes and their effect on cell function, the relationships between these changes are also important. Over the past decade, thousands of single disease-related mononucleotide polymorphisms have been identified in genome-related studies. Studies in this field have shown that the expression of...
Synthesis & Characterization of Au-HKUST-1 Nanocomposite and Evaluation of Plasmonic Properties of Gold Nanoparticles in this Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Madaah Hosseini, Hamid Reza (Supervisor)
Abstract
In the past few years, many research works on the controllable integration of metal nanoparticles and metal-organic frameworks were done, since the obtained composite material shows a synergism effect in catalysis and photocatalysis, drug delivery applications, gas, and energy storage, as well as sensing. For the first time, in this study, we employed template-assisted growth to synthesize Au-HKUST-1 Nanocomposite. XRD analysis entirely confirms that employing this strategy in synthesizing Au-HKUST-1 was wholly successful, and the plasmonic properties of this nanostructure were studied via UV-visible spectroscopy. In the course of synthesis, gold nanoparticles with 70nm diameter were...