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noise-levels
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Indoor Noise Pollution Modeling: A Case Study on Resalat Tunnel
, M.Sc. Thesis Sharif University of Technology ; Vaziri, Manouchehr (Supervisor)
Abstract
Noise or noise pollution, is defined as an unwanted sound, produced mostly by motor vehicles in urban areas. If the noise exceeds its limit, adverse effects on users and citizens are expected. Thus the assessment of the noise level and its comparison with allowable values is mandatory. Traffic induced noise depends upon different factors such as traffic, weather, and, sound barriers. Noise pollution study has a long history all over the world. Many studies, mostly representing the outdoor noise pollution models, have been done in recent years. This paper presents an assessment of traffic-induced noise in a heavily traveled tunnel, locally referred to as Resalat tunnel, which is located in...
Experimental and numerical investigation of the effect of a speed bump on car noise emission level
, Article Applied Acoustics ; Volume 68, Issue 11-12 , 2007 , Pages 1346-1356 ; 0003682X (ISSN) ; Hodaei, M ; Alimohammadi, I ; Sharif University of Technology
2007
Abstract
The noise emission level associated with two types of speed reducers has been investigated numerically and experimentally for different dimensions and different speeds of vehicle (20, 40 and 60 km/h) and zero acceleration. Numerical analysis has been performed using an FEM method in the ANSYS environment. The experiments show that for a bump of height 0.04 m, the peak noise level is increased by between 1 and 14 dB (A) whereas, for bump of height 0.055 m, the peak noise level increases by between 1 and 19 dB (A). There is an excellent agreement between the numerical and experimental results. © 2006 Elsevier Ltd. All rights reserved
UMP, ALR and GLR tests and some applications to coherent radar detection
, Article 2000 IEEE International Symposium on Information Theory, Serrento, 25 June 2000 through 30 June 2000 ; 2000 , Pages 388- ; 21578095 (ISSN) ; Nayebi, M. M ; Sharif University of Technology
2000
Abstract
A necessary and sufficient condition for the equivalence of two test functions is stated, also a necessary and sufficient condition for the existance of UMP test is proposed. Then it is shown, for the first time, that in coherent radar detection, UMP test does not exist and ALR and GLR detectors are not equivalent
Design and Fabrication of Electrical Field Sensor for Biological and Corrosion Currents Application
, M.Sc. Thesis Sharif University of Technology ; Simchi, Abdolreza (Supervisor) ; Fardmanesh, Mehdi (Supervisor)
Abstract
Electric field sensors are one of the common types of sensors that are widely used today to record changes in the electric field in underwater environments, also record pH changes in different materials. This type of sensor is inspired by the shark mucous membrane. In this study, silver / silver chloride silver (Ag / AgCl) was used for three methods of silver filtration directly in electrolyte containing chloride ion, Electrophoretic electrode method and electrode making method using silver oxide adhesive. Part of the electrodes manufacturing method involves converting part of silver into silver chloride. The made electrode has a length of 7 cm and a diameter of 0.5 mm, with its core made of...
Fundamental mode fluxgate magnetometers for active magnetic shielding
, Article 2011 19th Iranian Conference on Electrical Engineering, ICEE 2011, 17 May 2011 through 19 May 2011 ; May , 2011 , Page(s): 1 ; ISSN : 21647054 ; 9789644634284 (ISBN) ; Eshraghi, M. J ; Forooghi, F ; Sarreshtedari, F ; Fardmanesh, M ; Sharif University of Technology
2011
Abstract
Fluxgate magnetometers with different design and core materials have been made. The sensors have been characterized and the frequency responses of the sensors have been measured. The fluxgate magnetometer based on orthogonal design and amorphous wire core working in fundamental mode reaches 30pT/Hz noise level and 40μV/nT sensitivity. Finally an active magnetic shield constructed based on the amorphous core fluxgate magnetometer reaches more than 60dB field attenuation for DC field and has a good response for frequencies below 100Hz
Transmission of non-linear binary input functions over a CDMA system
, Article IEEE International Symposium on Information Theory - Proceedings, 1 July 2012 through 6 July 2012 ; July , 2012 , Pages 1401-1405 ; 9781467325790 (ISBN) ; Gohari, A ; Aghaeinia, H ; Sharif University of Technology
2012
Abstract
We study the problem of transmission of binary input non-linear functions over a network of mobiles based on CDMA. Motivation for this study comes from the application of using cheap measurement devices installed on personal cellphones to monitor environmental parameters such as air pollution, temperature and noise level. Our model resembles the MAC model of Nazer and Gastpar except that the encoders are restricted to be CDMA encoders. Unlike the work of Nazer and Gastpar whose main attention is transmission of linear functions, we deal with non-linear functions with binary inputs. A main contribution of this paper is a lower bound on the computational capacity for this problem. While in the...
Identifiability of location and magnitude of flow barriers in slightly compressible flow
, Article SPE Journal ; Volume 21, Issue 3 , 2016 , Pages 899-908 ; 1086055X (ISSN) ; Mansoori Habibabadi, M ; Joosten, G. J. P ; Van Den Hof, P. M. J ; Jansen, J. D ; Sharif University of Technology
Society of Petroleum Engineers
Abstract
Classic identifiability analysis of flow barriers in incompressible single-phase flow reveals that it is not possible to identify the location and permeability of low-permeability barriers from production data (wellbore pressures and rates), and that only averaged reservoir properties in between wells can be identified. We extend the classic analysis by including compressibility effects. We use two approaches: a twin experiment with synthetic production data for use with a time-domain parameter-estimation technique, and a transfer-function formalism in the form of bilaterally coupled four-ports allowing for an analysis in the frequency domain. We investigate the identifiability, from noisy...
Analysis of nonlinear oscillations in spur gear pairs with approximated modelling of backlash nonlinearity
, Article Mechanism and Machine Theory ; Volume 51 , 2012 , Pages 14-31 ; 0094114X (ISSN) ; Salarieh, H ; Sharif University of Technology
2012
Abstract
Due to international competition and strict limitations of standards regarding the noise level, investigation of gear vibration is of great importance. In this paper, nonlinear oscillations of spur gear pairs including the backlash nonlinearity is studied. Dynamic system is described through the classical single degree of freedom (SDOF) model in terms of dynamic transmission error (DTE). Using multiple scale method, forced vibration responses of the gear system including primary, super-harmonic and sub-harmonic resonances are investigated. In each case, the jump phenomenon and stability analysis are studied. In addition, the effect of dynamic and manufacturing parameters of the gear system...
Comparison of noise reduction techniques in RF SQUID magnetic detection systems
, Article Proceedings - 2010 18th Iranian Conference on Electrical Engineering, ICEE 2010, 11 May 2010 through 13 May 2010 ; 2010 , Pages 446-449 ; 9781424467600 (ISBN) ; Sarreshtedari, F ; Forooghi, F ; Fardmanesh, M ; Schubert, J ; Banzet, M ; Sharif University of Technology
Abstract
The noise level of the magnetometer and gradiometer RF SQUIDs were investigated using different shielding methods. The used methods include different active and passive shielding, such as Helmholtz configurations, locally compensation coils, superconducting bulks and μ-metal shields. For the passive shielding approach, using FEM simulation we have investigated the shielding effectiveness of superconducting bulks versus the use of μ-metal shielding. The superconducting shield is a YBCO circular bulk, which was made using melt-texture method and located in a distance in front of the SQUID. In this work the results of these shielding methods are presented and compared, while their effectiveness...
Exact solution for elliptic localization in distributed MIMO radar systems
, Article IEEE Transactions on Vehicular Technology ; Volume 67, Issue 2 , February , 2018 , Pages 1075-1086 ; 00189545 (ISSN) ; Behnia, F ; Maleki Sadr, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Elliptic localization is a range-based positioning technique exploiting multiple transmitter-receiver pairs, each of which provides separate bistatic range (BR) measurements. In this paper, a novel computationally efficient solution for locating a single target from BR measurements in distributed MIMO radar systems is proposed. Due to nonconvex nature of the associated maximum likelihood (ML) estimation problem, its globally optimal solution is difficult to obtain. We first reformulate the ML estimation as a nonconvex constrained weighted least squares problem. Owing to special structure of the resulting problem, it is recast as a convex problem, whose exact solution can be obtained in...
A novel method for measuring the MTF of CT scanners: A phantom study
, Article 2019 IEEE International Symposium on Medical Measurements and Applications, MeMeA 2019, 26 June 2019 through 28 June 2019 ; 2019 ; 9781538684276 (ISBN) ; Hosseini, S. A ; Reza Ay, M ; Safarzadehamiri, A ; Ghafarian, P ; Zaidi, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
The modulation transfer function (MTF) is well known as a crucial parameter in quality assurance of computed tomography (CT) scanners, which provides detailed information of both contrast and resolution of CT images. Different methods have been introduced and developed to calculate the MTF of CT scanners. However, a robust methodology which accurately estimates the MTF of CT scanners under the use of every range of object electron density and tube current-time product (mAs) has not been reported so far. To this aim, a new wavelet-based circular edge method for MTF measurement has been presented in this work. Owning to the edge spread function (ESF) susceptibility to noise, the approach was...