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MIMO Radars Waveform Design
, M.Sc. Thesis Sharif University of Technology ; Behnia, F (Supervisor)
Abstract
MIMO radar is a next generation radar which transmits arbitrary waveforms at each one of its apertures. It has been shown that design of waveforms for MIMO radars in order to synthesize a desired spatial beampattern, is mapped into a waveform correlation matrix (R) design in the narrowband case. Therefore, waveform design in MIMO radar for beamforming could be broken into two steps, namely correlation matrix design and waveform synthesis for achieving given R. As of now, given a desired beampattern or estimated location information of targets, calculating R has been modeled as an optimization problem like SDP. Also, in some special cases like rectangular beampattern, close form solutions for...
MIMO radar beamforming using orthogonal decomposition of correlation matrix
, Article Circuits, Systems, and Signal Processing ; Volume 32, Issue 4 , 2013 , Pages 1791-1809 ; 0278081X (ISSN) ; Behnia, F ; Sharif University of Technology
2013
Abstract
MIMO radar is the next generation radar which transmits arbitrary waveforms at each one of its apertures. It has been shown that the design of waveforms for MIMO radars in order to synthesize a desired spatial beampattern is mapped into a waveform correlation matrix R design in the narrowband case. As of now, given a desired beampattern or estimated locations information of targets, calculating R has been modeled as an optimization problem like semi-definite programming. Also, in some special cases like rectangular beampattern, closed-form solutions for R has been proposed. In this paper, we introduce a fast algorithm which is capable of designing R in order to achieve more arbitrary...
Transmit beampattern synthesis using eigenvalue decomposition in MIMO radar
, Article ICICS 2011 - 8th International Conference on Information, Communications and Signal Processing, 13 December 2011 through 16 December 2011 ; December , 2011 , Page(s): 1 - 5 ; 9781457700309 (ISBN) ; Behnia, F ; Sharif University of Technology
2011
Abstract
MIMO radar is the next generation radar which transmits arbitrary waveforms at each one of its apertures. It has been shown that design of waveforms for MIMO radars in order to synthesize a desired spatial beampattern is mapped into a waveform correlation matrix (R) design in the narrowband case. Searching for desired R has been modeled as a convex optimization problem which demands considerable processing power. There are also some close form solutions for special cases like rectangular beampatterns. Here we deal with the problem from a matrix eigenvalue theory perspective and show how close form solutions can be found for more general cases relaxing high computational power demand. Our...
Fixed-Mix Rules in an Evolutionary Market Using a Factor Model for Dividends
, M.Sc. Thesis Sharif University of Technology ; Zamani, Shiva (Supervisor)
Abstract
In this thesis, we simulate the competition between some investment strategies based on dividends with each other and with mean-variance strategy (Markowitz) in an evolutionary finance framework. We perform simulations by two different approaches. In the first one, we use real dividend data and, in the second one we use dividends that are generated according to a dividend factor model. The dividend factor model which relates the dividends to the macro-economic factors is estimated from data using principal component analysis. Our simulations show that in this competition, the evolutionary portfolio rule will eventually hold the total market wealth. According to this simple rule the portfolio...
Extract Non-Line-of-Sight state of base stations and error mitigation technique for wireless localization in micro-cell networks
, Article Computer Communications ; Volume 35, Issue 7 , 2012 , Pages 885-893 ; 01403664 (ISSN) ; Golmohammadi, S ; Shadi, K ; Sharif University of Technology
2012
Abstract
Non Line of Sight (NLOS) propagation is a challenging issue which the performance of network based wireless localization is limited by errors primarily caused by NLOS corruption. NLOS is inherently a dominant source of errors in metropolitan area wireless networks, like cellular one, so in this paper we discuss our proposed algorithm within cellular network terminology. This paper contributes two novel algorithms. The first one is to extract the NLOS state of base station (BS) and the second one is a correction algorithm to enhance the measurements accuracy. Our proposed algorithm discuses a novel localization technique to estimate true mobile terminal (MT) location from a set of possibly...
Well-conditioned sensor placement for range-only localization
, Article 2011 4th IFIP International Conference on New Technologies, Mobility and Security, NTMS 2011 - Proceedings, 7 February 2011 through 10 February 2011 ; February , 2011 , Page(s): 1 - 5 ; ISSN : 21574952 ; 9781424487042 (ISBN) ; Dehghani, H. L ; Gholampour, I ; Sharif University of Technology
2011
Abstract
This paper addresses the optimality of Network topology for localization purposes when measurements are range-only. Localization procedures based on TOA and TDOA range measurements are considered in this paper. As of now, the optimal placement of fixed terminals to locate mobile terminals has been studied based on Cramer-Rao Lower Bound (CRLB). CRLB is a universal bound on the variance of a general unbiased estimator and therefore is not dependent to the estimator and methods of localization. Here we introduce another algorithm dependent criterion, based on perturbation theory of linear equations. Different optimal topologies are presented using the new criterion. These optimal topologies,...
Inverse design of compact power divider with arbitrary outputs for 5G applications
, Article Scientific Reports ; Volume 12, Issue 1 , 2022 ; 20452322 (ISSN) ; Tavakol, M. R ; Atlasbaf, Z ; Sharif University of Technology
Nature Research
2022
Abstract
Since the recent on-demand applications need more sophisticated circuits and subsystems, components with configurable capabilities attract attention more than before in commercial systems, specifically the fifth generation (5G). Power dividers play a crucial role in 5G phased array systems, and their role becomes more significant if the output powers ratio is adjustable. Here, we suggest a design methodology by which planar power splitters with arbitrary output power levels can be designed in light of very simple perturbations, i.e., vias. Through our design procedure, we find an optimized pattern for hybrid vias-some of them are made of PEC, and others are dielectric, e.g., air,...
Joint Modelling of Telecommuting’s Feasibility and Freguency for Employees, Application of Copula Models
, M.Sc. Thesis Sharif University of Technology ; Kermanshah, Mohammad (Supervisor)
Abstract
Since expansion of communication technology, telecommuting has gained attention from transportation planners as an approach in field of demand management. In this research, joint effects of feasibility of telecommuting for the employees of each organization and the relevant frequency of employees have been evaluated by using the copula model as the most recent conventional way of developing a joint model since the last few years. The result of telecommuting acceptance is that after presenting the project to each organization, the head employer measures the appropriateness of the project for employees and if he reaches a consensus on the success of the project, the employees get involved and...
Studying the Effect of Applying Different Refrigerants in Ground Source Heat Exchangers
, M.Sc. Thesis Sharif University of Technology ; Hakkaki-Fard, Ali (Supervisor)
Abstract
Economical strategy of developed countries imposes to improve energy efficiency and a rational renewable energies usage in the buildings. Ground source heat pumps are one of the most important tools in the way moving toward this goal. This study focuses on studying the effect of applying different refrigerants in the direct expansion ground source heat exchangers. In order to compare the performance of the ground source heat pumps using different refrigerants, a specific methodology is presented and implemented. First on this study, the thermal performance of a geothermal borehole filled with both CO2 and a zeotropic mixture of CO2 and R32 (20/80) is studied and the quality, temperature, and...
Immobilization of α -chymotrypsin on the surface of magnetic/gold core/shell nanoparticles
, Article Journal of Nanotechnology ; Volume 2013 , 2013 ; 16879503 (ISSN) ; Vossoughi, M ; Sharif University of Technology
Hindawi Publishing Corporation
2013
Abstract
Over the last decade, nanoparticles used as protein carriers have opened new avenues for a variety of biomedical applications. The main concern for these applications is changes in biological activity of immobilized proteins due to conformational changes on the surface of the carrier. To evaluate this concern, the preparation and biocatalyst activity of α-chymotrypsin-Fe 3O4 @ Au core/shell nanoparticles were investigated. First, Fe3O4 @ Au core/shell nanoparticles were synthesized by coprecipitation method and citrate reduction of HAuCl 4. TEM imaging revealed a core size of 13 ± 3 nm and a shell thickness of 4 ± 1 nm for synthesized nanoparticles. X-ray diffraction (XRD) was used to study...
An Interior Needle Electropolymerized Pyrrole-Based Coating for Headspace Solid-Phase Dynamic Extraction of Chlorophenols
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
Nowadays, the inside needle capillary adsorption trap (INCAT) technique as a solventless sample preparation approach and alternative extraction method derived from SPME is gaining rising attentions. The INCAT and needle-trap devices are inexpensive, robust, reusable, and are applicable for sampling and analyzing suitable organic compounds from many different sample matrices. Compared to the fragile silica-based SPME fiber, the needle device is nearly impossible to break mechanically. In addition, the extraction medium possesses quite a large extraction phase volume and a powerful preconcentration capability. Similar to SPME, needle-like devices are particularly convenient for automation and...
GPH: A group-based partitioning scheme for reducing total power consumption of parallel buses
, Article Microprocessors and Microsystems ; Volume 35, Issue 1 , 2011 , Pages 68-80 ; 01419331 (ISSN) ; Koohi, S ; Hessabi, S ; Sharif University of Technology
2011
Abstract
Two main sources for power dissipation in parallel buses are data transitions on each wire and coupling between adjacent wires. So far, many techniques have been proposed for reducing the self and coupling powers. Most of these methods utilize one (or more) control bit(s) to manage the behavior of data transitions on the parallel bus. In this paper, we propose a new coding scheme, referred to as GPH, to reduce power dissipation of these control bits. GPH coding scheme employs partitioned Bus Invert and Odd Even Bus-Invert coding techniques. This method benefits from Particle Swarm Optimization (PSO) algorithm to efficiently partition the bus. In order to reduce self and coupling powers of...
Control of Nonlinear Systems With Predefined Output Transient Performance
, M.Sc. Thesis Sharif University of Technology ; Shahrokhi, Mohammad (Supervisor)
Abstract
This project is aimed to design a controller for nonlinear systems that satisfy a prescribed performance while guaranteeing close-loop stability. To do this, the controller must be designed in such a way that the transient response of the system has had these performance indices and does not exceed them. These performance indices predefine some constraints for systems’ output.A comprehensive form for the model system, the unknown dynamics of the system, consideration of a variety of constraints on the system input, usage of the time-finite method for the residence time and consideration of just one tuning parameter to reduce the computation load, are among the other benefits for the proposed...
Role of Base Metal Composition in Isothermal Solidification Time During Diffusion Brazing of Nickelbased Superalloys
, M.Sc. Thesis Sharif University of Technology ; Pouranvari, Majid (Supervisor)
Abstract
The nickel-based superalloys play a key role in the development of aircraft and power-generation turbines due to their exceptional properties of high temperature strength, toughness, crack growth resistance and resistance to degradation corrosive and oxidisation environment.In this thesis, the role of base metal composition in isothermal solidification time during diffusion brazing of Nickel-based super alloys was investigated. To achieve this aim, four different super alloys Hynes230, Hastalloy X, Nimonic 263 and Monel were used in similar joining systems. Systems of H230/H230, HX/HX, C263/C263, and Monel/Monel were joined by BNi2 interlayer at 1323K and for different times, until the...
A novel partitioned encoding scheme for reducing total power consumption of parallel bus
, Article 13th International Computer Society of Iran Computer Conference on Advances in Computer Science and Engineering, CSICC 2008, Kish Island, 9 March 2008 through 11 March 2008 ; Volume 6 CCIS , 2008 , Pages 90-97 ; 18650929 (ISSN); 3540899847 (ISBN); 9783540899846 (ISBN) ; Koohi, S ; Hessabi, S ; Sharif University of Technology
2008
Abstract
Two main sources for power dissipation in parallel buses are data transitions on each wire and coupling between adjacent wires. There are many techniques for reducing the transition and coupling powers. These methods utilize extra control bits to manage the behavior of data transitions on parallel bus. In this paper, we propose a new coding scheme which tries to reduce power dissipation of control bits. The proposed method employs partitioned Bus Invert and Odd Even Bus Invert coding techniques. This method benefits from Particle Swarm Optimization (PSO) algorithm to efficiently partition the bus. In order to reduce transition and coupling power of control bits, it finds partitions with...
A Framework for Evaluating the Effect of Queue on Customer Perception
, M.Sc. Thesis Sharif University of Technology ; Najmi, Manouchehr (Supervisor)
Abstract
Queue is crucial in new atmosphere of business. Firms and people see the dark side of this phenomenon. Investigation on The other side of queue is our main purpose of this study. Examining the relationship between queue and Perceived Quality, Price, Sacrifice, Value, and willingness to buy that make our conceptual framework and hypotheses is our primary objective.Questionnaire designed for evaluating construct. For each construct, standard scale was used. A survey was conducted in Iranian universities. The final sample includes 295 respondents. Regression analyses were performed.Results show significant relationship between our construct that confirm the other side of queue. Results show...
GABIST: A new methodology to find near optimal LFSR for BIST structure
, Article 14th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2007, Marrakech, 11 December 2007 through 14 December 2007 ; 2007 , Pages 1107-1110 ; 1424413788 (ISBN); 9781424413782 (ISBN) ; Salmani Jelodar, M ; Hessabi, S ; Sharif University of Technology
2007
Abstract
Fault coverage and test time have important roles in using Built in self-test (BIST). Two parameters are crucial and effective in BIST design: LFSR's polynomial (or configuration) and its initial seed. In this paper we propos a practical method for finding near optimal LFSR with genetic algorithm (GA) and show that LFSR is a good TPG compared with other TPGs. In this method, the candidate seeds are achieved through a deterministic approach, and an evolutionary approach is employed to obtain the LFSR configurations for the desired fault coverage under test time constraint. The configurations are encoded in binary chromosomes. The evolution process evolves the fittest configurations to achieve...
Elastic Responses of a Half-Space Reinforced by a Buried Extensible Membrane under Internal Loading
, M.Sc. Thesis Sharif University of Technology ; Eskandari, Morteza (Supervisor)
Abstract
In order to improve mechanical properties and increase the load capacity of soil so many different methods are innovated and utilized. Through This variety we can mention cement and asphalt concrete pavements which are the most common methods, cement sprinkling for consolidation of inclined surfaces and utilizing geotextiles and geomembranes which are recent methods. As far as a method becomes more common in industry, analytical study on effect of these methods on soil properties drew more attention in researches.In this research a homogenous elastic half-space is reinforced by an extensible thin plate and studied under various loads. The plate is considered as a buried infinite plane with...
A stability-based model of a growing spine with adolescent idiopathic scoliosis: A combination of musculoskeletal and finite element approaches
, Article Medical Engineering and Physics ; Volume 64 , 2019 , Pages 46-55 ; 13504533 (ISSN) ; Rouhi, G ; Arjmand, N ; Adeeb, S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Using a combined musculoskeletal and finite element (FE) approach, this study aimed to evaluate stability-based muscle forces in a spine with adolescent idiopathic scoliosis (AIS) as compared to a normal spine; and subsequently, determine the effects of stress distribution on the growth plates (GPs) of the growing spine. For this purpose a nonlinear 3D FE model of one normal and one scoliotic thoracolumbar spine, consisting of GPs attached to rigid L1 to L4 vertebrae, were developed using computed tomography images coupled with a growth modulation using the Stokes’ model. Corresponding well with recent in-vivo and in-vitro studies, results of the models predicted intradiscal pressures at the...
Degradation of benzene, toluene, and xylene (BTX) from aqueous solution by isolated bacteria from contaminated sites
, Article Research on Chemical Intermediates ; Volume 41, Issue 1 , January , 2015 , Pages 265-275 ; 09226168 (ISSN) ; Yaghmaei, S ; Vafaei, F ; Khataee, A. R ; Hejazi, M. S ; Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
The present study was carried out to evaluate the degradation efficiency of benzene, toluene, and xylene (BTX) by isolated bacteria from various petroleum-hydrocarbons contaminated sites. Five isolated bacteria were selected for testing BTX biodegradation from liquid culture media. Each of these bacteria was able to degrade BTX but with different efficiencies. Maximum biodegradation efficiency for benzene (more than 70 %) was obtained by Gram-positive coccobacillus, Gram-positive coccus and Gram-negative bacillus bacteria, for toluene (60 %) and xylene (70 %) by Gram-positive coccobacillus and Gram-negative coccobacillus. It was found that the presence of xylene in the substrate mixture...