Loading...
Search for:
khanipour-roshan--alireza
0.26 seconds
Total 610 records
Design, Manufacture and Flight Dynamics Analysis of A Handlaunched Solar UAV
, M.Sc. Thesis Sharif University of Technology ; Banazadeh, Afshin (Supervisor)
Abstract
Hand-launched UAVs are type of unmanned aerial vehicles that due to transportability and geometric specification, are operationally valuable and worthy. reconnaissance & surveillance (aerial mapping, aerial filming, inspection, border protection); health care (blood transport, body organ transport, medicine delivery); agriculture (farm monitoring, fertilization, cloud seeding); payload delivery (envelopes posting); network covering (internet supply, telecommunication relay); crisis management (remote area medical) are some of typical applications and missions of this type of aircrafts. These UAVs have almost low altitude short endurance (below 5000 ft. and less than 2 hrs.). To extend their...
Magnetic Field Assistedand Flow Injection μ-Solid Pahse Extraction Techniques
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
The main goal of this thesis was to develop μ-solid extraction techniques using electrspun nanofibers under the influence of magnetic field along with flow injection system. The thesis is divided into two sections:The first chapter deals with the use of magnetic field for improving μ-solid phase extraction efficiencies. After preparing the magnetic-based electrospun nanofibers (PBt/MNPs), sufficient numbers of disc from the prepared electrospun composite mat were cut and used as packing materials in a cartridge. The prepared system was coupled on-line to liquid chromatography for microextraction of selected drugs of furosemide, naproxene, diclofenac and clobetasol propionate. The homogeneity...
HMM based semi-supervised learning for activity recognition
, Article SAGAware'11 - Proceedings of the 2011 International Workshop on Situation Activity and Goal Awareness, 18 September 2011 through 18 September 2011, Beijing ; September , 2011 , Pages 95-99 ; 9781450309264 (ISBN) ; Rabiee, H. R ; Pourdamghani, N ; Khanipour, P ; Sharif University of Technology
2011
Abstract
In this paper, we introduce a novel method for human activity recognition that benefits from the structure and sequential properties of the test data as well as the training data. In the training phase, we obtain a fraction of data labels at constant time intervals and use them in a semi-supervised graph-based method for recognizing the user's activities. We use label propagation on a k-nearest neighbor graph to calculate the probability of association of the unlabeled data to each class in this phase. Then we use these probabilities to train an HMM in a way that each of its hidden states corresponds to one class of activity. These probabilities are used to learn the transition probabilities...
Risk Action Plans’ Cost Optimization by Considering Risks’ Interdependency
, M.Sc. Thesis Sharif University of Technology ; Shadrokh, Shahram (Supervisor)
Abstract
Risk management, one of the knowledge areas in project management, plays a key role in the success of projects in today’s unstable situation. The massive cost reduction achieved by risk management can manifest its importance even more in huge construction projects in gas and oil industry such as developments of power plants and petrochemical complexes. In this research, the effect of considering the correlation between risks and consequently the effect of risk action plans on other risks in their execution cost reductions has been demonstrated. A questionnaire has been designed, many experts have been interviewed, and using statistical methods, the risks’ interdependencies have been...
Developing New Methods for Determining the Compressive Strength of Concrete
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
Believing that the strength obtained from the standard 150300 mm2 cylindrical specimens, introduced by the ACI, cannot be a proper representative of what concrete experiences as part of a structure under loading, in this project an attempt was made to develop new methods for testing concrete specimens to find their strength. In order to avoid making new molds and to use standard 150300 mm2 molds, various innovative measures, proposed by the supervisor of this project, were used to work out the strength of tested concretes. While the results obtained from limited number of tests carried out in this work did not show much difference between the results of the standard ACI test with those of...
Fuzzy Fractional Order PID Design
, M.Sc. Thesis Sharif University of Technology ; Sadati, Naser (Supervisor)
Abstract
In this thesis a novel Fuzzy Fractional Order Controller (FFOPID) is presented. This controller is designed by the means of the combination of a fuzzy system and a fractional order PID. Fractional controllers, especially fractional PIDs, shows their performance in control systems after the advent of fractional calculus. Fractional PID has better flexibility according to the classic PID. As the real control systems are nonlinear actually, so solving the control problem needs a nonlinear controller. Therefore, a fuzzy system is used in this thesis, in order to adapt the controller parameters with different operating points of the system. Fuzzy system design needs the optimal values for...
RANS simulations of the stepped duct effect on the performance of ducted wind turbine
, Article Journal of Wind Engineering and Industrial Aerodynamics ; Volume 145 , October , 2015 , Pages 270-279 ; 01676105 (ISSN) ; Alimirzazadeh, S ; Rad, M ; Sharif University of Technology
Elsevier
2015
Abstract
With the rise in oil price and population growth, renewable energies are assumed to be the main source of energies for the next generation. Wind as a natural, eco-friendly and renewable source of energy has been at the center of concentration for decades. Recently there has been some ideas regarding the self-regulating urban wind turbines. Researchers have shown that a proper enclosure increases the wind velocity and therefore more torques can be exerted on the rotors, therefore more power can be generated. These enclosures are light and cheap, therefore they are applicable and effective. In the present study, an enclosure was modified to increase the exerted torque with implementing a step...
Recognition and the Nature of Self-consciousness in Fichte and Hegel
, M.Sc. Thesis Sharif University of Technology ; Abazari, Arash (Supervisor)
Abstract
For both Fichte and Hegel, self-consciousness is an intersubjective concept; that is, for them, self-consciousness is necessarily constituted between, at least, two subjects. In Foundations of Natural Right, Fichte introduces summons and recognition as necessary conditions of self-consciousness, without which, i.e. an other who is calling upon the subject, the subject cannot be conscious at all. Hegel, in Phenomenology of Spirit, also says self-consciousness is desire which is satisfied only in another (self-) consciousness. Based on these ideas, I try to show that self-consciousness can be defined as having the both in view; the self (I) and the other (not-I), at the same time. In this...
Unsteady RANS simulation of a surface piercing propeller in oblique flow
, Article Applied Ocean Research ; Volume 56 , 2016 , Pages 79-91 ; 01411187 (ISSN) ; Zabihzade Roshan, S ; Seif, M. S ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Conventional propellers might undergo severe cavitation at high speeds and this phenomenon not only affects the efficiency of the propeller, but also may result in serious damages in propulsion system. Due to their special geometries, surface piercing propellers (SPPs) overcome this problem and achieve high efficiencies in high speeds. Therefore, SPPs are one of the popular propulsors for high-speed crafts. The present research is aimed to pursue SPP's performance in the off-design conditions. URANS method was used to study the performance of the 841-SPP (case with some available experimental results; Olofsson, 1996) in several immersion ratios (= 33%, 50%, 75% and 100%) and maneuvering...
Discovering and Improving the Processes of an Iranian Psychiatric Hospital Using Process Mining
, M.Sc. Thesis Sharif University of Technology ; Hassan Nayebi, Erfan (Supervisor)
Abstract
Providing quality hospital services depends on the efficient and correct implementation of processes. Therapeutic care processes are a set of activities that are carried out with the aim of diagnosing, treating and preventing any disease in order to improve and promote the patient's health. The purpose of this study is to use process mining techniques to discover and improve healthcare processes. The case study of this research is a psychiatric hospital in Shiraz. The approach implemented in this research consists of three main stages including data pre-processing, model discovery phase, and analysis phase. Three algorithms including Heuristic Miner, Inductive Miner, and ILP Miner were used...
Crystallization of hydroxyapatite during hydrothermal treatment on amorphous calcium phosphate layer coated by PEO technique
, Article Ceramics International ; Volume 39, Issue 2 , 2013 , Pages 1793-1798 ; 02728842 (ISSN) ; Arbabi, A ; Mehdinezhad Roshan, A ; Sharif University of Technology
2013
Abstract
Surface modification of titanium implants is recently considered by several researchers. In this study, PEO was performed over commercially Ti-6Al-4V alloy pellets in an aqueous electrolyte containing calcium acetate (C.A.) and calcium glycerphosphate (Ca-GP) with a Ca/P molar ratio of 6.8, and applying current density of 0.212 A/cm2, frequency of 100 Hz and duty ratio of 60% for 4 min. In the next step, hydrothermal treatments were carried out for various durations and at different temperatures inside an autoclave chamber containing a NaOH solution with pH of 11.5. XRD and SEM results confirmed formation of needle-shaped HAp after all hydrothermal conditions. Maximum intensity of HAp peaks...
Dielectrophoretic cell sorting via sliding cells on 3D silicon microelectrodes
, Article Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 22 January 2017 through 26 January 2017 ; 2017 , Pages 147-150 ; 10846999 (ISSN) ; 9781509050789 (ISBN) ; Chan, M. L ; Roshan, K. A ; Yobas, L ; Sharif University of Technology
2017
Abstract
This work presents an innovative design for a flow-through dielectrophoretic cell sorting based on silicon bulk microelectrodes featuring sidewall undercuts. The microelectrodes are configured into an interdigitated array with digits extending across the flow chamber at an oblique angle against the flow stream. Target cells under dielectrophoretic forces and hydrodynamic drag can slide along the digits to a dedicated outlet. The design has been showcased for continuous-flow sorting of viable and non-viable mammalian cells, achieving a throughput of 16,600 cells/min, an order of magnitude higher than those reported for existing continuous-flow cell sorting designs using thin-film or...
Estimation of modal parameters using bilinear joint time-frequency distributions
, Article Mechanical Systems and Signal Processing ; Volume 21, Issue 5 , 2007 , Pages 2125-2136 ; 08883270 (ISSN) ; Shamsollahi, M. B ; Mobed, M ; Behzad, M ; Sharif University of Technology
2007
Abstract
In this paper, a new method is proposed for modal parameter estimation using time-frequency representations. Smoothed Pseudo Wigner-Ville distribution which is a member of the Cohen's class distributions is used to decouple vibration modes completely in order to study each mode separately. This distribution reduces cross-terms which are troublesome in Wigner-Ville distribution and retains the resolution as well. The method was applied to highly damped systems, and results were superior to those obtained via other conventional methods. © 2006 Elsevier Ltd. All rights reserved
Modal parameters identification using bilinear joint time-frequency analysis
, Article International Conference on Noise and Vibration Engineering 2006, ISMA 2006, Heverlee, 18 September 2006 through 20 September 2006 ; Volume 5 , 2006 , Pages 2907-2919 ; Mobed, M ; Shamsollahi, M. B ; Behzad, M ; Sharif University of Technology
Katholieke Universiteit Leuven
2006
Abstract
In this paper, a new method for modal parameter estimation using time-frequency representations is presented. Smoothed Pseudo Wigner-Ville representation which is a member of the Cohen's class distributions is used that reduces cross-terms in time-frequency plane dramatically and holds resolution as well. The method was applied to systems with high damping, and the results were superior to other conventional methods. © (2006) by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved
Investigating the effect of ultrasound intensity on the magnetic properties of magnetite nanostructures synthesized by sonochemical method
, Article International Journal of Engineering, Transactions B: Applications ; Volume 36, Issue 6 , 2023 , Pages 1034-1039 ; 1728144X (ISSN) ; Vaezi, M. R ; Koohestani, H ; Cheraghi, F ; Sharif University of Technology
Materials and Energy Research Center
2023
Abstract
In this article, the synthesis of magnetite nanostructures was successfully carried out by the sonochemical process. In this method, stoichiometric amount of iron chlorides (FeCl3.6H2O and FeCl2.4H2O), ammonia (NH3) and polyvinylpyrolidone (PVP) were used to synthesize pure Fe3O4 nanoparticles. The effect of initial sonication power of the ultrasonic device on the size and morphology of the final products as one of the effective parameters was investigated. For this, the initial power of the sonicator was evaluated at 90, 70, 50 and 30 W at 40°C. Characterization of Fe3O4 nanoparticles was done by transmission electron microscope (TEM) and X-ray powder diffraction (XRD) and its magnetic...
Performance characterization of a low-cost dual-channel camera-based microarray scanner
, Article 24th Iranian Conference on Electrical Engineering, ICEE 2016, 10 May 2016 through 12 May 2016 ; 2016 , Pages 1534-1538 ; 9781467387897 (ISBN) ; Ghobeh, M ; Ghiasvand, E ; Akbari Roshan, K ; Motahari, S. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper, we have proposed, designed, implemented, and characterized a low-cost camera-based microarray scanner which is capable of imaging fluorescently-labeled DNA or Protein microarrays. The proposed system is designed to simultaneously measure two different fluorescent dyes using two parallel channels which increase the overall scan speed. We have shown that the wide dynamic range of system makes it able to detect fluorophore densities from 100-106 molecule/μm2. In each capture, a 5.6 mm × 3.7 mm field is imaged on a 22.3 mm × 14.9 mm (18 megapixels) CMOS sensor. Therefore, the microarray can be scanned with ∼ 1μm2 spatial resolution which is high enough to distinguish borders of...
Energy- and Reliability-Aware Active Strategies for Mixed-Criticality Cyber-Physical Systems
, M.Sc. Thesis Sharif University of Technology ; Ansari, Mohsen (Supervisor) ; Hessabi, Shaahin (Supervisor)
Abstract
The expansion of Cyber-Physical Systems (CPSs) in diverse domains, including automotive, aerospace, and healthcare, has led to increased challenges for these systems in the last decade. With the increasing complexity of the functions performed by these systems, Mixed-Criticality Systems (MCSs) that integrate tasks with different criticality levels have attracted much attention. These systems often have a heterogeneous multiprocessor architecture and use Directed Acyclic Graphs (DAGs) to model task dependencies. This paper proposes a fault-tolerant scheduling algorithm that manages energy consumption and reliability while considering the Deadline Miss Ratio (DMR) in heterogeneous...
Rcci Curvature for Metric-Measure Space via Optimal Transport
, M.Sc. Thesis Sharif University of Technology ; Bahraini, Alireza (Supervisor) ; Ranjbar Motlagh, Alireza (Co-Advisor)
Abstract
One of the important questions in mathematics is generalized. In case of metric spaces, one of the questions is: Can we extend notions of Riemannian geometry to arbitrary metric spaces smoothly? Ricci curvature is one of the most important concepts in differential geometry. Ricci curvature is defined for the Riemannian manifold and has many applications in mathematics and physics like Einstein’s equation in relativity theory. There is a good notion for a metric space having “sectional curvature bounded below by K” or “sectional curvature bounded above by K”, due to Alexandrov. Can we define the concept of Ricci curvature in metric space? A motivation for this question comes from Gromov’s...
Slope variation effect on large deflection of compliant beam using analytical approach
, Article Structural Engineering and Mechanics ; Volume 44, Issue 3 , 2012 , Pages 405-416 ; 12254568 (ISSN) ; Ganji, D. D ; Roshan, N ; Moheimani, R ; Hatami, M ; Hasanpour, A ; Sharif University of Technology
2012
Abstract
In this study the investigation of large deflections subject in compliant mechanisms is presented using homotopy perturbation method (HPM). The main purpose is to propose a convenient method of solution for the large deflection problem in compliant mechanisms in order to overcome the difficulty and complexity of conventional methods, as well as for the purpose of mathematical modeling and optimization. For simplicity, a cantilever beam of linear elastic material under horizontal, vertical and bending moment end point load is considered. The results show that the applied method is very accurate and capable for cantilever beams and can be used for a large category of practical problems for the...
Isograph: Neighbourhood graph construction based on geodesic distance for semi-supervised learning
, Article Proceedings - IEEE International Conference on Data Mining, ICDM, 11 December 2011 through 14 December 2011 ; December , 2011 , Pages 191-200 ; 15504786 (ISSN) ; 9780769544083 (ISBN) ; Mahdieh, M ; Rabiee, H. R ; Roshan, P. K ; Rohban, M. H ; Sharif University of Technology
2011
Abstract
Semi-supervised learning based on manifolds has been the focus of extensive research in recent years. Convenient neighbourhood graph construction is a key component of a successful semi-supervised classification method. Previous graph construction methods fail when there are pairs of data points that have small Euclidean distance, but are far apart over the manifold. To overcome this problem, we start with an arbitrary neighbourhood graph and iteratively update the edge weights by using the estimates of the geodesic distances between points. Moreover, we provide theoretical bounds on the values of estimated geodesic distances. Experimental results on real-world data show significant...