Seismic response of infilled steel braced frames by endurance time analysis

, Article Asian Journal of Civil Engineering ; Volume 21, Issue 4 , 2020 , Pages 611-624 Jamshidi Avanaki, M ; Abedi, M ; Estekanchi, H. E ; Sharif University of Technology

Springer 2020

Abstract

Infill walls are realized to affect the nonlinear response of infilled frames. Yet, due to modeling and analysis complexities, infill walls are usually neglected in the modeling and analysis phase. In this paper, the nonlinear behavior of infilled steel braced frames is investigated using the Endurance Time (ET) method. The ET method is a novel and straightforward approach for the nonlinear analysis of structures under dynamic excitations. Two 2D braced frames, one concentrically braced frame and one eccentrically braced frame, with unreinforced masonry clay brick walls as infills, are considered. The infill panels are macro-modeled using equivalent compressive struts, with appropriate...

Collapse Analysis of Infilled Steel Frames by Endurance Time Method

, M.Sc. Thesis Sharif University of Technology Jamshidi Avanaki, Mohammad (Author) ; Esmaeil Pourestekanchi, Homayun (Supervisor)

Abstract

In many urban and rural areas, steel frames are infilled by masonry materials such as bricks. The resulting structural system is commonly known as an infilled frame. Nonlinear analysis of infilled frames using conventional analysis methods, such as incremental dynamic analysis (IDA), requires high levels of modeling complexity and computational effort, therefore in most practical cases; the infill panel is often neglected. Such an approximation results in a high level of inconsistency in evaluation of the actual behavior (e.g. lateral strength and stiffness) of these frames. Introducing more simple and straightforward methods of analysis and design for these frames, can be a solution to this...

Hierarchical Enhancement of Optical Coherence Tomography Images

, Article 24th Iranian Conference on Biomedical Engineering and 2017 2nd International Iranian Conference on Biomedical Engineering, ICBME 2017, 30 November 2017 through 1 December 2017 ; 2018 ; 9781538636091 (ISBN) Turani, Z ; Fatemizadeh, E ; Nasiri Avanaki, M ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2018

Abstract

Optical coherence tomography (OCT) is a noninvasive imaging modality that provides cross-sectional images from microstructures of tissues. This optical imaging system works based on Michelson interferometry principle and has intermediate resolution and penetration depth which makes it appropriate for imaging thin tissues such as skin and eye. OCT images suffer from three main artifacts that make images difficult to be analyzed. The first one is small grainy structures called speckle which degrade image quality and decreases axial and lateral resolution. The second one is light intensity attenuation which is a function of depth. It happens because of absorbing and scattering nature of tissue...

Comparative assessment of five algorithms to control an SLM for focusing coherent light through scattering media

, Article Photons Plus Ultrasound: Imaging and Sensing 2018, 28 January 2018 through 1 February 2018 ; Volume 10494 , 2018 ; 16057422 (ISSN); 9781510614734 (ISBN) Fayyaz, Z ; Mohammadian, N ; Avanaki, M. R. N ; Sharif University of Technology

SPIE 2018

Abstract

Light propagation in turbid media, such as biological tissues, experience scattering due to inhomogeneous distribution of refractive indices. Control of light scattering is important for focusing the light or imaging through scattering medium. By spatially shaping the wave-front of the incident beam, using spatial light modulator (SLM), the scattered light can be focused to a point. Iterative optimization is a popular way of obtaining the most optimum phase map on the SLM. In this study, we implement six optimization algorithms including continuous sequential, partitioning algorithm, transmission matrix estimation method, genetic algorithms, particle swarm optimization, and simulated...

Wavelet-based unbalanced un-equivalent multiple description coding for P2P networks

, Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 242-247 ; 1424410940 (ISBN); 9781424410941 (ISBN) Firooz, M. H ; Ronasi, K ; Pakravan, M. R ; Nasiri Avanaki, A ; Sharif University of Technology

2007

Abstract

Almost all existing multi-description coding (MDC) schemes are designed for media streaming over Internet. In this work, a wavelet-based video MDC technique is introduced that fits the criteria of media streaming over peer-to-peer networks. Our proposed method assigns descriptions to the senders due to their characteristic (i.e. bandwidth and availability). In contrast to traditional MDC, different descriptions in the proposed method have different importance in remaking the original media. Our simulation results show considerable improvement of video quality at the receiver (up to 10 dB) as compared to the state-of-the-art. ©2007 IEEE

An enhanced random-walk method for content locating in P2P networks

, Article 27th International Conference on Distributed Computing Systems Workshops, ICDCSW'07, Toronto, ON, 22 June 2007 through 29 June 2007 ; 2007 ; 0769528384 (ISBN); 9780769528380 (ISBN) Ronasi, K ; Firooz, M. H ; Pakravan, M. R ; Nasiri Avanaki, A ; Sharif University of Technology

2007

Abstract

The important problem of content location in an unstructured distributed network (such as P2P, with no central searching system, graph construction control or file placement regulation) is addressed. The existing methods that are based on either flooding or random walk impose a large traffic load on the network or require a long time to search. In this work, we propose a method that outperforms the existing methods in both of these measures. These advantages are achieved by publishing traces of the contents of each node in its nearby nodes, so that the closer nodes to the target have a stronger trace of it. Such traces are used to rapidly locate the desired content. The superb performance of...

IPROMISE: Reliable multi-sender algorithm for peer-to-peer networks

, Article 2007 2nd International Conference on Communication System Software and Middleware and Workshops, COMSWARE 2007, Bangalore, 7 January 2007 through 12 January 2007 ; 2007 ; 1424406145 (ISBN); 9781424406142 (ISBN) Firooz, M. H ; Ronasi, K ; Pakravan, M. R ; Nasiri Avanaki, A ; Sharif University of Technology

2007

Abstract

Due to the constraints of P2P networks (such as bandwidth limitation) multiple senders should be employed for reliable multimedia streaming. This paper introduces a mathematic approach to select a set of senders among all available senders to provide the most reliable stream for the receiver. This selection is based on upload bandwidths and availability of peers as well as bandwidth of links connecting the senders and the receiver. Our method is called IPROMISE as it is an improved version of the PROMISE algorithm. Simulation results demonstrate improved media quality delivered to the receiver, while the complexity of sender selection remains the same. © 2007 IEEE

A fast algorithm for construction of minimum delay multicast trees in P2P networks

, Article 2006 International Symposium on Communications and Information Technologies, ISCIT, Bangkok, 18 October 2006 through 20 October 2006 ; 2006 , Pages 137-142 Ronasi, K ; Firooz, M. H ; Pakravan, M. R ; Avanaki, A. N ; Sharif University of Technology

2006

Abstract

Peer to Peer networks have received considerable attention during the past decade and have been the focus of many research and development activities. New applications such as video streaming or gaming would benefit from multicast topologies and creating such trees in peer to peer networks is a challenging task. Proper multicast trees should minimize the traffic delay and bandwidth consumption. At the same time, construction of these trees should not be very complicated in terms of the required processing power so they can be implemented easily. The required time for construction of multicast trees should also be minimized and that helps with their adaptation to the dynamics of the network....

A novel multi-sender algorithm based on multi-cast concept for P2P networks

, Article 2006 International Symposium on Communications and Information Technologies, ISCIT, Bangkok, 18 October 2006 through 20 October 2006 ; 2006 , Pages 143-147 Firooz, M. H ; Ronasi, K ; Pakravan, M. R ; Avanaki, A. N ; Sharif University of Technology

2006

Abstract

Unlike those on Internet, the media providers on P2P networks are ordinary nodes whose contribution bandwidth is limited. Multi-sender methods are the best solutions known to video streaming on P2P networks. In this paper, we propose use of a multi-cast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. That is while the existing multi-sender methods maximize the bit-rate delivered to the first receiver and cannot provide acceptable bit-rates to the next requesting nodes. © 2006 IEEE

A fast and reliable multi-sender algorithm for peer-to-peer networks

, Article Journal of Network and Computer Applications ; Volume 32, Issue 3 , 2009 , Pages 733-740 ; 10848045 (ISSN) Firooz, M. H ; Nasiri Avanaki, A. R ; Pakravan, M. R ; Ronasi, K ; Sharif University of Technology

2009

Abstract

Due to special constraints in peer-to-peer (P2P) networks (such as bandwidth limitation) and because of their highly dynamic characteristics, a single node cannot provide a reliable multimedia stream to the receivers. Several multi-sender algorithms are proposed to reliably deliver a media stream to the receiver through the intrinsically unreliable P2P networks. Based on upload bandwidths and availability of peers as well as the bandwidths of the links connecting the senders and the receiver, PROMISE selects a set of active senders to maximize the expected bit-rate delivered to the receiver. By careful investigation of PROMISE, in this paper, we present why and how it deviates from finding...

A multi-sender multicast algorithm for media streaming on peer-to-peer networks

, Article Computer Communications ; Volume 30, Issue 10 , 2007 , Pages 2191-2200 ; 01403664 (ISSN) Firooz, M. H ; Ronasi, K ; Pakravan, M. R ; Nasiri Avanaki, A. R ; Sharif University of Technology

2007

Abstract

Unlike those on Internet, the media providers on P2P networks are ordinary nodes with limited shared resources such as bandwidth. Multi-sender methods are the best existing solutions to video streaming on P2P networks. In this paper, we propose use of a multicast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. Experimental results, derived from implementation of the proposed algorithm on Pastry P2P network confirm our claim. Another advantage of our method over the existing methods is its scalability with the number of receivers. © 2007 Elsevier B.V. All rights reserved

Modeling of point and non-point source pollution of nitrate with SWAT in the Jajrood river watershed, Iran

, Article International Agricultural Engineering Journal ; Volume 19, Issue 2 , 2010 , Pages 23-31 ; 08582114 (ISSN) Jamshidi, M ; Tajrishy, M ; Maghrebi, M ; Sharif University of Technology

2010

Abstract

The Latian dam reservoir is one of the most important drinking water sources for Tehran, Iran. Nitrate is a major water quality problem in this reservoir. The Jajrood River, the most important water source for the reservoir, discharges large amounts of nutrients to it every year including high levels of nitrate, a pollutant of particular concern. This study presents the results obtained from simulating different point source and nonpoint source impacts on the fate and transport of nitrate in the 470 km2 Jajrood watershed using the Soil and Water Assessment Tool (SWAT) model version 2000 (SWAT2000). The SWAT model was calibrated and validated over an extended time period (1997-2005) for this...

Assessment of jajrood river watershed microbial pollution: Sources and fates

, Article Environmental Engineering and Management Journal ; Volume 9, Issue 3 , 2010 , Pages 385-391 ; 15829596 (ISSN) Maghrebi, M ; Tajrishy, M ; Jamshidi, M ; Sharif University of Technology

2010

Abstract

The Jajrood River watershed is on of the main drinking water resurces of Tehran, the capital city of Iran. In addition it provides many recreational usages. However, a variety of microbial pollutions is commonly perecived in the Jajrood River, among them a high concentration of coliform group bacteria that has caused strong concerns. In this article, different aspects of microbial pollution as well as the main microbial pollution sources in the region are discussed. Coliform group bacterial die-off rates have been evaluated as the key parameters that govern bacterial fate in the watershed and were estimated using both laboratory and field data investigations. The high values of the bacterial...

Photoacoustic signal enhancement: Towards utilization of low energy laser diodes in real-time photoacoustic imaging

, Article Sensors (Switzerland) ; Volume 18, Issue 10 , 2018 ; 14248220 (ISSN) Manwar, R ; Hosseinzadeh, M ; Hariri, A ; Kratkiewicz, K ; Noei, S ; Avanaki, M. R. N ; Sharif University of Technology

MDPI AG 2018

Abstract

In practice, photoacoustic (PA) waves generated with cost-effective and low-energy laser diodes, are weak and almost buried in noise. Reconstruction of an artifact-free PA image from noisy measurements requires an effective denoising technique. Averaging is widely used to increase the signal-to-noise ratio (SNR) of PA signals; however, it is time consuming and in the case of very low SNR signals, hundreds to thousands of data acquisition epochs are needed. In this study, we explored the feasibility of using an adaptive and time-efficient filtering method to improve the SNR of PA signals. Our results show that the proposed method increases the SNR of PA signals more efficiently and with much...

A comparative study of optimization algorithms for wavefront shaping

, Article Journal of Innovative Optical Health Sciences ; Volume 12, Issue 4 , 2019 ; 17935458 (ISSN) Fayyaz, Z ; Mohammadian, N ; Rahimi Tabar, M. R ; Manwar, R ; Avanaki, K ; Sharif University of Technology

World Scientific Publishing Co. Pte Ltd 2019

Abstract

By manipulating the phase map of a wavefront of light using a spatial light modulator, the scattered light can be sharply focused on a specific target. Several iterative optimization algorithms for obtaining the optimum phase map have been explored. However, there has not been a comparative study on the performance of these algorithms. In this paper, six optimization algorithms for wavefront shaping including continuous sequential, partitioning algorithm, transmission matrix estimation method, particle swarm optimization, genetic algorithm (GA), and simulated annealing (SA) are discussed and compared based on their efficiency when introduced with various measurement noise levels

Optical coherence tomography confirms non-malignant pigmented lesions in phacomatosis pigmentokeratotica using a support vector machine learning algorithm

, Article Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI) ; Volume 29, Issue 6 , 2023 , Pages e13377- ; 16000846 (ISSN) Lee, J ; Beirami, M.J ; Ebrahimpour, R ; Puyana, C ; Tsoukas, M ; Avanaki, K ; Sharif University of Technology

NLM (Medline) 2023

Abstract

INTRODUCTION: Phacomatosis pigmentokeratotica (PPK), an epidermal nevus syndrome, is characterized by the coexistence of nevus spilus and nevus sebaceus. Within the nevus spilus, an extensive range of atypical nevi of different morphologies may manifest. Pigmented lesions may fulfill the ABCDE criteria for melanoma, which may prompt a physician to perform a full-thickness biopsy. MOTIVATION: Excisions result in pain, mental distress, and physical disfigurement. For patients with a significant number of nevi with morphologic atypia, it may not be physically feasible to biopsy a large number of lesions. Optical coherence tomography (OCT) is a non-invasive imaging modality that may be used to...

Wall stress estimation of human heart under the effect of high accelerations

, Article ASME 2013 Summer Bioengineering Conference, SBC 2013 ; Volume: 1 , 2013 ; 9780791855614 (ISBN) Jamshidi, M ; Ahmadian, M. T ; Sharif University of Technology

2013

Abstract

Human body is constantly under the influence of acceleration loads in environments such as combat flying. This study investigates the effect of body acceleration on human heart function by using finite element analysis. The nonlinear mechanical behavior of myocardium is modeled by Yeoh hyperelastic model. Stress-strain curves of myocardium are determined based on uniaxial compression tests on bovine heart samples. Nonlinear least square curve fitting is conducted in order to obtain material parameters. Heart geometrical modeling in threedimension is done by segmentation of cardiac MRI images. Obtained material coefficients are assigned to the constructed heart model and appropriate pressure...

Investigation of the effect of high +Gz accelerations on human cardiac function

, Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 27 , 2013 , Pages 54-63 ; 17516161 (ISSN) Jamshidi, M ; Ahmadian, M. T ; Sharif University of Technology

2013

Abstract

This study investigates the effect of body acceleration on human cardiac function. Finite element analysis is conducted to simulate geometrical and mechanical properties of human heart. Heart geometrical modeling in three-dimension is performed by segmentation of cardiac MRI images. The nonlinear mechanical behavior of myocardium is modeled by Mooney-Rivlin, Polynomial, Ogden and Yeoh hyperelastic material models. Stress-strain curves of myocardial tissue are obtained from experimental compression tests on bovine heart samples. The experimental results are employed for the evaluation of material coefficients by the nonlinear least squares method. Among hyperelastic models, the Yeoh model...

A new coded cooperation scheme for wireless communications and its performance analysis

, Article International Journal of Wireless Information Networks ; Volume 15, Issue 1 , 2008 , Pages 43-52 ; 10689605 (ISSN) Jamshidi, A ; Nasiri Kenari, M ; Sharif University of Technology

2008

Abstract

We propose a new coded cooperation scheme for wireless communications to obtain transmit diversity in the scenarios that agents such as mobile handsets, sensor network nodes and etc., due to size, power or other constraints, cannot utilize multiple antennas. New scheme supports more than two cooperative users with a relatively low cooperation level. We evaluate the performance of the proposed scheme in a frequency nonselective slow fading channel. For two cooperative users, we provide the exact analytical analysis. However, for more than two users, as the analytical analysis is very complicated, our performance evaluation is based on computer simulations. Our numerical results show that each...

Performance analysis of transmitter-side cooperation-receiver-side-relaying schemes for heterogeneous sensor networks

, Article IEEE Transactions on Vehicular Technology ; Volume 57, Issue 3 , 2008 , Pages 1548-1563 ; 00189545 (ISSN) Jamshidi, A ; Nasiri Kenari, M ; Sharif University of Technology

2008

Abstract

In this paper, we present two physical layer cooperative protocols for heterogeneous sensor networks. There is one cooperator near the transmitter and a second cooperator (as a relay) near the receiver. Although the focus is on heterogeneous sensor networks, the methods can be applied to homogeneous sensor networks as well. Analytical and simulation results show that, under an additive white Gaussian noise channel assumption for the links between the transmitter and its partner and between the receiver and its partner, the proposed protocols achieve a diversity order of three or four by using the amplify-and-forward cooperation strategy and maximal ratio combining in the receiver. In...