Analysis and Improvement of Agile Software Development Process Using Process Mining and Machine Learning Algorithms

, M.Sc. Thesis Sharif University of Technology Fardipour Asl, Mohsen (Author) ; Hassan Nayebi, Erfan (Supervisor)

Abstract

In the competitive world of software development, IT product development teams face numerous challenges and issues within business processes. In recent years, the combination of process mining and machine learning algorithms to optimize software development processes has gained attention. However, there is still a lack of a comprehensive model for identifying and conducting root-cause analysis of problems and providing solutions based on them in agile software development systems. The aim of this research is to find a solution for identifying and addressing issues in the software development process by modifying the change request workflow and examining various aspects of incidents. To...

Band-gap narrowing and electrochemical properties in N-doped and reduced anodic TiO2 nanotube arrays

, Article Electrochimica Acta ; Volume 270 , 2018 , Pages 245-255 ; 00134686 (ISSN) Peighambardoust, N. S ; Khameneh Asl, S ; Mohammadpour, R ; Khameneh Asl, S ; Sharif University of Technology

Elsevier Ltd 2018

Abstract

Electrochemical activity of TiO2 nanotube arrays (NTAs) is restricted by a wide band gap of TiO2. To overcome this restriction, we considered systematic research on two effective methods of doping of TiO2 NTAs such as the N-doping and electrochemical reductive doping and predicting the proper application of them. Band gap narrowing was occurred from 3.16 eV for undoped TiO2 NTAs to 2.9 and 2.7 eV at N-doped and self-doped TiO2 ones respectively. The electrochemical responses of the TiO2 NTAs before and after doping were examined by cyclic Voltammetry (CV) curve. To understand the electrochemical behavior of the undoped and doped TiO2 NTAs, electrochemical impedance spectroscopy (EIS) was...

Improved efficiency in front-side illuminated dye sensitized solar cells based on free-standing one-dimensional TiO2 nanotube array electrodes

, Article Solar Energy ; Volume 184 , 2019 , Pages 115-126 ; 0038092X (ISSN) Peighambardoust, N. S ; Khameneh Asl, S ; Mohammadpour, R ; Khameneh Asl, S ; Sharif University of Technology

Elsevier Ltd 2019

Abstract

Although morphological disorder of nanotube structure is further down than the nanoparticular electrode, its density of traps are the hindering effects in the charge transport. In this study, crack-free TiO2 nanotube membranes, which obtained through a re-anodizing process, are fixed on transparent fluorine–tin-oxide glass by applying a few drops of Titanium Isopropoxide without needing the TiO2 powder paste. Front-side illuminated dye sensitized solar cells fabricated by undoped, N-doped and blue TiO2 nanotube membranes are investigated. The electrical characteristics of TiO2 nanotube based dye sensitized solar cells are followed by theoretical analysis using simple one-diode model....

MMRO: A feature selection criterion for MR images based on alpha stable filter responses

, Article 2011 7th Iranian Conference on Machine Vision and Image Processing, MVIP 2011 - Proceedings ; 2011 ; 9781457715358 (ISBN) Abbasi Asl, R ; Fatemizadeh, E ; Sharif University of Technology

2011

Abstract

In feature-based image registration, feature selection and reduction methods play an important role in decreasing computational burden of these operations. In this paper, a new approach is introduced to reduce the dimension of extracted feature vectors of MR images. This approach is based on the selection of the maximum and minimum responses of the alpha stable filter for the MR images over the extracted features with different orientation in frequency domain. This algorithm selects the rotation invariant features which are suitable for image registration purposes. It has been shown that these features could efficiently describe the image elements. The discriminating ability of the features...

Seismic hazard assessment for two cities in Eastern Iran

, Article Earthquake and Structures ; Volume 8, Issue 3 , 2015 , Pages 681-697 ; 20927614 (ISSN) Farzampour, A ; Kamali Asl, A ; Sharif University of Technology

Techno Press 2015

Abstract

Iran as one of the countries located on the Alpine-Himalayan seismic belt has recently experienced a few number of catastrophic earthquakes. A well-known index of how buildings are affected by earthquakes is through assessment of probable Peak Ground Acceleration (PGA) and structures' response spectra. In this research, active faults around Kerman and Birjand, two major cities in eastern parts of Iran, have been considered. Seismic catalogues are gathered to categorize effects of surrounding faults on seismicity of the region. These catalogues were further refined with respect to time and space based on Knopoff-Gardner algorithm in order to increase statistical independency of events....

Percolation theory in reservoir engineering

, Book King, P. R ; Masihi, Mohsen

World Scientific 2018

Integration of the inertial navigation system with consecutive images of a camera by relative position and attitude updating

, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 233, Issue 15 , 2019 , Pages 5592-5605 ; 09544100 (ISSN) Ghanbarpour Asl, H ; Dehghani Firouzabadi, A ; Sharif University of Technology

SAGE Publications Ltd 2019

Abstract

This paper introduces a new method for improving the inertial navigation system errors using information provided by the camera. An unscented Kalman filter is used for integrating the inertial measurement unit data with the features’ constraints extracted from the camera’s image. The constraints, in our approach, comprise epipolar geometry of two consecutive images with more than 65% coverage. Tracking down a known feature in two consecutive images results in emergence of stochastic epipolar constraint. It emerges in the form of an implicit measurement equation of the Kalman filter. Correctly matching features of the two images is necessary for reducing the navigation system errors because...

Synthesis, characterization and fluorescence spectra of mixed ligand Zn(II), Cd(II) and Hg(II) complexes with 1,10-phenanthroline-5,6-dione ligand

, Article Journal of Coordination Chemistry ; Volume 60, Issue 15 , 2007 , Pages 1629-1635 ; 00958972 (ISSN) Boghaei, D. M ; Behzadian Asl , F ; Sharif University of Technology

2007

Abstract

The novel mixed ligand complexes [M(bpy)(phen-dione)](PF6)2 (M = Zn(II), Cd(II) and Hg(II), bpy = 2,2′-bipyridine and phen-dione = 1,10-phenanthroline-5,6-dione) have been synthesized and characterized by elemental analysis, IR, 1H NMR and electronic absorption spectroscopies. The ν(C=O) of coordinated phen-dione in these complexes are very similar to the free phen-dione ligand showing that phen-dione is not coordinated to metal ion from its C=O sites. Absorption spectra of the complexes show two absorption bands for intraligand transitions. These absorption bands show dependence to the dielectric constant of solvent. These complexes exhibit an intensive fluorescence band around 535 nm in...

Synthesis, characterization and fluorescence spectra of mononuclear Zn(II), Cd(II) and Hg(II) complexes with 1,10-phenanthroline-5,6-dione ligand

, Article Journal of Coordination Chemistry ; Volume 60, Issue 3 , 2007 , Pages 347-353 ; 00958972 (ISSN) Boghaei, D. M ; Behzadian Asl, F ; Sharif University of Technology

2007

Abstract

The mononuclear complexes of Zn(II), Cd(II) and Hg(II), [Zn(phen-dione)Cl2], [Cd(phen-dione)Cl2] and [Hg(phen-dione)Cl2], where phen-dione = 1,10-phenanthroline-5,6-dione, have been synthesized and characterized by elemental analysis and IR, 1H NMR and electronic absorption spectroscopies. The ν(C=O) of coordinated phen-dione ligands in these complexes shows that the phen-dione is not coordinated to metal ion from its C=O sites. Electronic spectra of the complexes show two absorption bands for intraligand transitions. These absorption bands show dependence on the dielectric constant of solvents. These complexes exhibit an intense fluorescence band around 545 nm in DMSO when the excitation...

An adaptive unscented Kalman filter for quaternion-based orientation estimation in low-cost AHRS

, Article Aircraft Engineering and Aerospace Technology ; 2007 , Pages 485-493 ; 00022667 (ISSN) ; Volume 79, Issue 5 Pourtakdoust, S. H ; Ghanbarpour Asl, H ; Sharif University of Technology

2007

Abstract

Purpose - This paper aims to develop an adaptive unscented Kalman filter (AUKF) formulation for orientation estimation of aircraft and UAV utilizing low-cost attitude and heading reference systems (AHRS). Design/methodology/approach - A recursive least-square algorithm with exponential age weighting in time is utilized for estimation of the unknown inputs. The proposed AUKF tunes its measurement covariance to yield optimal performance. Owing to nonlinear nature of the dynamic model as well as the measurement equations, an unscented Kalman filter (UKF) is chosen against the extended Kalman filter, due to its better performance characteristics. The unscented transformation of the UKF is shown...

Ductility evaluation of confined high-strength concrete flexural members

, Article Iranian Journal of Science and Technology, Transaction B: Technology ; Volume 25, Issue 1 , 2001 , Pages 129-131 ; 03601307 (ISSN) Khaloo, A. R ; Tariverdilu Asl, S ; Sharif University of Technology

2001

Abstract

The influence of concrete strength on the ductility of RC flexural members is investigated. Tests were carried out on beams with three ranges of concrete strengths, and moment-curvature and deflection curves obtained. It is concluded that when the concrete is laterally confined by closed steel ties beams with various levels of concrete strength and very high tensile strength steel exhibit high ductility

Nonlocal hcp kernel functions based on ab initio calculations: Pertinent dislocation problems revisited

, Article Mechanics of Materials ; Volume 160 , 2021 ; 01676636 (ISSN) Shahvaghar Asl, S ; Shodja, H. M ; Sharif University of Technology

Elsevier B.V 2021

Abstract

Eringen's nonlocal theory and an accurate determination of the nonlocal kernel functions for hexagonal close-packed (hcp) crystals are of interest. The kernel functions are closely related to the anisotropy as well as any crystalline symmetries. To this end, five new distinct nonlocal kernel functions which have the characteristics of discrete atomistic Green's functions in the stress space are obtained through consideration of the nonlocal dispersion relations associated with certain directions combined with ab initio Density Functional Perturbation Theory (DFPT) calculations of the pertinent phonon frequencies. This is the first work which provides the nonlocal hcp kernel functions...

Discrete kernel functions for fcc crystals within eringen’s nonlocal theory of elasticity

, Article Journal of Elasticity ; Volume 143, Issue 1 , 2021 ; 03743535 (ISSN) Shodja, H. M ; Shahvaghar Asl, S ; Sharif University of Technology

Springer Science and Business Media B.V 2021

Abstract

The dilemma with the deficiencies of the nonlocal kernel functions as the building blocks of the Eringen’s nonlocal theory has been of concern. The aim of the current work is to provide a remedy for the calculation of the components of the nonlocal moduli tensor pertinent to face center cubic (fcc) crystals accounting for their true symmetry group. To this end, three new distinct nonlocal kernel functions which are the discrete atomistic Green’s functions in the stress space are obtained through the nonlocal dispersion relations associated with the longitudinal and shear waves in fcc crystals combined with the corresponding ones calculated via ab initio based on density functional...

Synthesis of Nano Porous Mixed Matrix Polymeric Membranes by TIPS Method for Gas Separation Application

, M.Sc. Thesis Sharif University of Technology Jahanbakhsh Asl, Hannaneh (Author) ; Soltanie, Mohammad (Supervisor)

Abstract

Mixed matrix membranes (MMMs) are new generation of membranes which possess simple processability of polymeric membranes and high separation ability of zeolitic membranes. The present study, concentrates on the fabrication of MMM for CO2/CH4 separation in a combined method as encompasses not only higher permeability but also superior selectivity in comparison with conventional polymeric membranes. The most appropriate technique for MMM making, is the process which provides participation of distributed zeolite particles in separation efficiently while the polymeric matrix acts just like a particle support and dose not play an effective role in separation. Investigations demonstrates that...

Autonomous Attitude and Position Determination of Satellites Using Earth Imagery

, M.Sc. Thesis Sharif University of Technology Samsami, Kiarash (Author) ; Ghanbarpour Asl, Habib (Supervisor)

Abstract

An autonomous method for attitude and position determination of a satellite without using data from ground stations and also without the need for human interference is proposed using the image that the satellite has taken at each moment. The proposed method is based on recognition of stable features in the image and using them in order to match the satellite image with a source image from the Earth and the latitude and longitude of the features become known.SIFT and SURF algorithms have been examined. Using the perspective equation and camera coordinate system, a model has been developed that relates the coordinates of a point in the image with its equivalent coordinates in the real world....

Modeling, Identification and Control of an Electrostatically Suspended Gyroscope

, M.Sc. Thesis Sharif University of Technology Siahatgar, Mohammad (Author) ; Ghanbarpour Asl, Habib (Supervisor)

Abstract

This paper presents a novel method for satellite attitude determination, using Electrostatically Suspended gyroscope (ESG). In this method, two superconducting rings rotated around a spherical rotor, which causes a variable flux in rings. So according to faraday’s law of induction, a voltage will be induced in the rings. Using this voltage and a kalman filter, attitude of satellite will be determined. ESG works precisely, when the rotor is maintain at the center of gyroscope cavity, between three pairs of circular electrode, so a backstepping control algorithm will be designed In order to this purpose. The performance of attitude determination using this ESG and designed control algorithm is...

Hybrid Design of Recommender Systems

, M.Sc. Thesis Sharif University of Technology Ahmadzadeh Asl, Ali (Author) ; Izadi, Mohammad (Supervisor)

Abstract

Nowadays recommender systems are one of the most important parts of big websites. These systems help users to find their intended items among enormous amounts of data. Traditionally, recommender systems are designed and implemented using different methods such as content based, collaborative and demographic filtering. Each of these methods had some problems that lead to emergence of a new kind of recommender systems called hybrid recommender systems. This kind of recommender systems try to combine the other methods and make them better. In this thesis, we have selected some previous recommender systems and then, we have made a new system by combining and reforming them. The resulted...

Production and Properties of Reduced Graphene Oxide- Zinc Nanocomposite Coating on Steel

, M.Sc. Thesis Sharif University of Technology Moshgi Asl, Somayyeh (Author) ; Afshar, Abdollah (Supervisor)

Abstract

In this project, graphene oxide was produced by chemical method (modified hummers method) because of simplicity and reproductiblity in the manufacuring process. Zinc nanoparticles were produced from pure zinc anode in the graphene oxide solution (anodic dissolution). Nanocomposite coating of reduced graphene oxide – zinc was created by electrochemical reduction with voltage pulse. Optimization of corrosion current density of the coating was done by design of experiments software (central composite design). To achieve this goal, several parameters such as cycles of zinc dissolution, frequency, duty cycle, total time of coating and applied voltage were examined. Using analysis of variance...

Structural and Computational Studies of Intra- and Intermolecular Interactions in Some New Chloro- and Nitro-cobaloxime Complexes

, M.Sc. Thesis Sharif University of Technology Alikhah Asl, Shervin (Author) ; Kia, Reza (Supervisor)

Abstract

In this study, a number of chloro and nitro cobaloxime complexes with triphenylarsine and triphenylstibine synthesized from dichloro precursor and their structure were studied. These complexes were identified by FT-IR and 1H-NMR methods also their solid state structure studied by X-ray crystallography of single crystals. Intramolecular interactions of these complexes analyzed and studied by NCIPLOT 3.0 and VMD 1.9.3 programs which has different kind of intramolecular interactions which can be identified by their colors. All these complexes have strong hydrogen bond between hydrogen of oxime group and oxygen of other dimethylglyoxime ligand. Also coordinate covalent bond among ligands and...

Direct Path Cancellation in Satellite Signal Based Forward Scattering Radar

, M.Sc. Thesis Sharif University of Technology Esmaeili Asl, Amin (Author) ; Behroozi, Hamid (Supervisor)

Abstract

Passive bistatic radars (PBR) using transmitters of opportunity have attracted a lot of attention recently. Advantages of these radars include the covert operation as well as the low cost of their building and maintenance. Such radars are intended to use signals in the environment as transmitters. These transmitters can be terrestrial transmitters such as TV broadcasts or even satellite transmitters such as global positioning system (GPS) satellites.Satellite transmitters have global coverage and their signal is available at all times, but the design of these transmitters for non-radar applications causes the reduction of the reception power at receivers. So BR systems have attempted to use...