Recognition of human speech phonemes using a novel fuzzy approach

, Article Applied Soft Computing Journal ; Volume 7, Issue 3 , 2007 , Pages 828-839 ; 15684946 (ISSN) Halavati, R ; Bagheri Shouraki, S ; Harati Zadeh, S ; Sharif University of Technology

2007

Abstract

Recognition of human speech has long been a hot topic among artificial intelligence and signal processing researches. Most of current policies for this subject are based on extraction of precise features of voice signal and trying to make most out of them by heavy computations. But this focus on signal details has resulted in too much sensitivity to noise and as a result, the necessity of complex noise detection and removal algorithms, which composes a trade-off between fast or noise robust recognition. This paper presents a novel approach to speech recognition using fuzzy modeling and decision making that ignores noise instead of its detection and removal. To do so, the speech spectrogram...

Artificial emotions for artificial systems

, Article 2008 AAAI Spring Symposium, Stanford, CA, 26 March 2008 through 28 March 2008 ; Volume SS-08-04 , 2008 , Pages 46-49 ; 9781577353607 (ISBN) Harati Zadeh, S ; Bagheri Shouraki, S ; Halavati, R ; Sharif University of Technology

2008

Abstract

To produce emotional artificial systems in AI domain, usually a subset of human emotional states are imported to the target domain and the major differences between natural and artificial domains are often ignored. In this paper we will discuss about why such an approach is not useful for all possible applications of emotions and we will show how it is necessary and possible to produce artificial emotion systems based on the target systems goals, abilities and needs

Emotional behavior: a resource management approach

, Article Adaptive Behavior ; Volume 14, Issue 4 , 2006 , Pages 357-380 ; 10597123 (ISSN) Harati Zadeh, S ; Bagheri Shouraki, S ; Halavati, R ; Sharif University of Technology

2006

Abstract

Emotions are the subject of study in many research areas, including psychology, physiology and artificial intelligence. However, there is not yet a general computational definition for emotions and many of the related works in artificial intelligence are based on uncertain assumptions about the origin, features, and applications of emotions. Therefore, we direct our studies toward achieving a better understanding of emotions and generating a computational model that could be a base for further research in the field. As a first step, we present the results of our study into the possible role of emotions in mental resource management. To do so, we will introduce a model of emotions based on...

Evolution of speech recognizer agents by artificial life

, Article Wec 05: Fourth World Enformatika Conference, Istanbul, 24 June 2005 through 26 June 2005 ; Volume 6 , 2005 , Pages 237-240 ; 9759845857 (ISBN) Halavati, R ; Bagheri Shouraki, S ; Harati Zadeh, S ; Lucas, C ; Ardil C ; Sharif University of Technology

2005

Abstract

Artificial Life can be used as an agent training approach in large state spaces. This paper presents an artificial life method to increase the training speed of some speech recognizer agents which where previously trained by genetic algorithms. Using this approach, vertical training (genetic mutations and selection) is combined with horizontal training (individual learning through reinforcement learning) and results in a much faster evolution than simple genetic algorithm. The approach is tested and a comparison with GA cases on a standard speech data base is presented. COPYRIGHT © ENFORMATIKA

A Model for Generating Emotional Behavior

, Ph.D. Dissertation Sharif University of Technology Harati Zadeh, Saman (Author) ; Bagheri Shouraki, Saeeid (Supervisor)

Abstract

After three decades of research, the concept of emotion as an aspect of initelligence in artificial systems, is still unclear. Most of emotion models in AI are aimed to simulate the emotional states of human in differenct levels of abstraction and functionality. Therefore, the concept of emotions in artificial systems is completely dependent on human being’s emotional states and can not be used as a general tool for improving the intellingence of artificial systems. In this thesis, we have tried to show that defining emotion in a more abstract level can expand the domain of its appications in AI. According to some existing theories about emotions, we modeled emotions as local semi-soloutions...

, M.Sc. Thesis Sharif University of Technology Harati, Mojtaba (Author) ; Moghaddam, Hassan (Supervisor)

Abstract

The observed response of medium rise buildings during sever earthquakes worldwide has indicated that RC buildings with shear walls behave considerably better than other buildings. The conviction that shear walls are inherently brittle still prevails amongst engineers, and therefore, they usually prefer to choose moment resisting RC frames without shear walls. In this study, a number of RC frames, with and without shear walls are designed in accordance with the seismic codes, and are then subjected to an assemble of severe earthquakes. The results of timehistory nonlinear analyses of these models are then used to investigate the effect of the presence of shear walls within the framework of...

Semisolid Stir Joining of AZ91 Alloy to A356 Alloy

, M.Sc. Thesis Sharif University of Technology Harati, Meysam (Author) ; Ashuri, Hossein (Supervisor)

Abstract

Today, Mg and Al as the widely used metals, make a special contribution to automotive, electronics and aerospace industries. Increasing the application of alloys of these metals, has extended the demand for reliable joint between alloys of these two metals. The main problem with the dissimilar joining of A356 alloy and AZ91 alloy is hard and brittle intermetallic compounds formation such as Mg17Al12 and Mg2Si which brings about welding strength reduction. By far, a large number of researches about dissimilar joining of AZ91 alloy and A356 alloy in semi-solid condition have not accomplished. In this method two fragments, one from AZ91 alloy and another from A356 alloy among which was a 2...

On the rectangle escape problem

, Article Theoretical Computer Science ; Volume 689 , 2017 , Pages 126-136 ; 03043975 (ISSN) Ahmadinejad, A ; Assadi, S ; Emamjomeh Zadeh, E ; Yazdanbod, S ; Zarrabi Zadeh, H ; Sharif University of Technology

2017

Abstract

Motivated by the bus escape routing problem in printed circuit boards, we study the following rectangle escape problem: given a set S of n axis-aligned rectangles inside an axis-aligned rectangular region R, extend each rectangle in S toward one of the four borders of R so that the maximum density over the region R is minimized. The density of each point p∈R is defined as the number of extended rectangles containing p. We show that the problem is hard to approximate to within a factor better than 3/2 in general. When the optimal density is sufficiently large, we provide a randomized algorithm that achieves an approximation factor of 1+ε with high probability improving over the current best...

Experimental evaluation of the effect of residual stress field on crack growth behaviour in C(T) specimen

, Article Engineering Fracture Mechanics ; Volume 73, Issue 13 , 2006 , Pages 1772-1782 ; 00137944 (ISSN) Farrahi, G. H ; Majzoobi, G. H ; Hosseinzadeh, F ; Harati, S. M ; Sharif University of Technology

2006

Abstract

The effects of the residual stress field resulting from shot peening and the indentation technique were investigated in relation to fatigue crack closure and crack growth behaviour. Compact Specimens of 20NiCrMo2 were used in this investigation. The regions of residual stress field were located behind the fatigue crack tip. Crack closure behaviour was measured with back face strain and crack mouth opening displacement gauges. Crack length was monitored by the compliance and microscopic methods. Residual stress was measured by the incremental hole-drilling method. Subsequently the closure level, propagation rate and resulting crack growth retardation were studied. Crack closure and attendant...

A probe into the fatigue crack growth in mechanical systems with hyperchaotic/chaotic dynamics

, Article Mechanical Systems and Signal Processing ; Volume 191 , 2023 ; 08883270 (ISSN) Dezfuli, M. A ; Zeinoddini, M ; Nazari, S. A ; Pasand, M. S ; Harati, R. M ; Sharif University of Technology

Academic Press 2023

Abstract

This study presents experimental and analytical fatigue frameworks for the dynamic fatigue life prediction of nonlinear mechanical systems under hyperchaotic oscillations. Fatigue in aluminium notched beams under hyperchaotic/chaotic vibrations is studied using a time-based analytical model. The fatigue lives obtained by the analytical model provided satisfactory correlations with those acquired by the dynamic fatigue experiments conducted on cracked aluminium beams. The model is then used to study the fatigue under Duffing chaotic, Duffing hyperchaotic, and periodic dynamic forcing. Results indicate that the classic linear cumulative damage rule delivers inaccurate high cycle fatigue (HCF)...

The maximum disjoint routing problem

, Article 22nd International Conference on Computing and Combinatorics, COCOON 2016, 2 August 2016 through 4 August 2016 ; Volume 9797 , 2016 , Pages 319-329 ; 03029743 (ISSN); 9783319426334 (ISBN) Shahmohammadi, F ; Sharif Zadeh, A. S ; Zarrabi Zadeh, H ; Sharif University of Technology

Springer Verlag 2016

Abstract

Motivated by the bus escape routing problem in printed circuit boards, we revisit the following problem: given a set of n axis-parallel rectangles inside a rectangular region R, find the maximum number of rectangles that can be extended toward the boundary of R, without overlapping each other. We provide an efficient algorithm for solving this problem in O(n2 log3 n log log n) time, improving over the current best O(n3)-time algorithm available for the problem

Solute-solvent interaction effects on second-order rate constants of reaction between 1-chloro-2,4-dinitrobenzene and aniline in alcohol-water mixtures

, Article International Journal of Chemical Kinetics ; Volume 37, Issue 2 , 2005 , Pages 90-97 ; 05388066 (ISSN) Harati, M ; Gholami, M. R ; Sharif University of Technology

2005

Abstract

The second-order rate coefficients for aromatic nucleophilic substitution reaction between 1-chloro-2,4-dinitrobenzene and aniline have been measured in aqueous solutions of ethanol and methanol at 25°C. The plots of rate constants versus mole fraction of water show a maximum in all-aqueous solutions. The effect of four empirical solvent parameters including hydrogen bond donor acidity (α), dipolarity/polarizability (π*). normalized polarity (ETN), and solvophobicity (Sp) has been investigated. This investigation has been carried out by means of simple and multiple regression models A dual-parameter equation of log k2 versus Sp and α was obtained in all-aqueous solutions (n = 41, r = 0.962,...

Learning overcomplete dictionaries from markovian data

, Article 10th IEEE Sensor Array and Multichannel Signal Processing Workshop, SAM 2018, 8 July 2018 through 11 July 2018 ; Volume 2018-July , 2018 , Pages 218-222 ; 2151870X (ISSN); 9781538647523 (ISBN) Akhavan, S ; Esmaeili, S ; Babaie Zadeh, M ; Soltanian Zadeh, H ; Sharif University of Technology

IEEE Computer Society 2018

Abstract

We explore the dictionary learning problem for sparse representation when the signals are dependent. In this paper, a first-order Markovian model is considered for dependency of the signals, that has many applications especially in medical signals. It is shown that the considered dependency among the signals can degrade the performance of the existing dictionary learning algorithms. Hence, we propose a method using the Maximum Log-likelihood Estimator (MLE) and the Expectation Minimization (EM) algorithm to learn the dictionary from the signals generated under the first-order Markovian model. Simulation results show the efficiency of the proposed method in comparison with the...

Seismic Performance Evaluation of RC Frames Rehabilitated by Different Techniques Using IDA

, M.Sc. Thesis Sharif University of Technology Mashhadi Harati, Rasoul (Author) ; Khalu, Alireza (Supervisor)

Abstract

Seismic behavior of multi-story frames widely has been studied in recently. So that such studies can lead the earthquakes-resistance system to better performance. The dramatic growth of computer processing power make it possible that nonlinear dynamic analysis of structures with great precision could be done. One of the advantages of nonlinear analysis is achieve behavioral performance of structures during an earthquake. Knowledge of the performance, enables us to identify structural weaknesses result in devising to improve these. The aim of this study is to evaluate the seismic performance of reinforced concrete frames have been improved, using different techniques. The frames are designed...

Experimental study on macro segregation behavior in short and wide range solidification of different aluminum alloys

, Article Materials Science and Technology Conference and Exhibition 2013, MS and T 2013 ; Volume 2 , 2013 , Pages 822-829 ; 9781629933092 (ISBN) Shafiei Zadeh, B ; Mohammad Salehi, E ; Hassan Nejad, H ; Shafiei Zadeh, S ; Sharif University of Technology

2013

Abstract

Data are presented on the solidification of aluminum alloys and their macro segregation behavior. Three alloys with different solidification ranges were prepared in two temperatures. Two types of molds were also prepared by sand and metallic materials. The solidification of Al alloys were studied and the effects of four parameters were determined, including cooling rate, casting temperature, degassing and nucleation effects on solidification and a comparison was conducted to Scheil model performance. Three types of aluminum alloys (Al-12.1%Si, Al-6.9%Si and Al-4.4% Cu) with short, medium and wide solidification ranges were studied and the results showed that degassing, nucleation, increasing...

A state-of-knowledge review on the endurance time method

, Article Structures ; Volume 27 , 2020 , Pages 2288-2299 Estekanchi, H. E ; Mashayekhi, M ; Vafai, H ; Ahmadi, G ; Mirfarhadi, S. A ; Harati, M ; Sharif University of Technology

Elsevier Ltd 2020

Abstract

The endurance time method is a time history dynamic analysis in which structures are subjected to predesigned intensifying excitations. This method provides a tool for response prediction that correlates structural responses to the intensity of earthquakes with a considerably less computational demand as compared to conventional time history analysis. The endurance time method is being used in different areas of earthquake engineering, such as performance-based assessment and design, life-cycle cost-based design, value-based design, seismic safety, seismic assessment, and multi-component seismic analysis. Successful implementation of the endurance time method relies heavily on the quality of...

The Minimum vulnerability problem

, Article Algorithmica ; Volume 70, Issue 4 , 2014 , pp 718-731 ; ISSN: 14320541 Assadi, S ; Emamjomeh-Zadeh, E ; Norouzi-Fard, A ; Yazdanbod, S ; Zarrabi-Zadeh, H ; Sharif University of Technology

2014

Abstract

We revisit the problem of finding (Formula presented.) paths with a minimum number of shared edges between two vertices of a graph. An edge is called shared if it is used in more than one of the (Formula presented.) paths. We provide a (Formula presented.)-approximation algorithm for this problem, improving the best previous approximation factor of (Formula presented.). We also provide the first approximation algorithm for the problem with a sublinear approximation factor of (Formula presented.), where (Formula presented.) is the number of vertices in the input graph. For sparse graphs, such as bounded-degree and planar graphs, we show that the approximation factor of our algorithm can be...

The minimum vulnerability problem

, Article Algorithmica ; Volume 7676 LNCS , 2012 , Pages 382-391 ; 14320541(ISSN) ; 9783642352607 (ISBN) Assadi, S ; Emamjomeh Zadeh, E ; Norouzi Fard, A ; Yazdanbod, S ; Zarrabi Zadeh, H ; Sharif University of Technology

2012

Abstract

We revisit the problem of finding k paths with a minimum number of shared edges between two vertices of a graph. An edge is called shared if it is used in more than one of the k paths. We provide a ⌊k/2⌋-approximation algorithm for this problem, improving the best previous approximation factor of k - 1. We also provide the first approximation algorithm for the problem with a sublinear approximation factor of O(n3/4), where n is the number of vertices in the input graph. For sparse graphs, such as bounded-degree and planar graphs, we show that the approximation factor of our algorithm can be improved to O(√n). While the problem is NP-hard, and even hard to approximate to within an O(log n)...

Seismic reliability assessment of structures using artificial neural network

, Article Journal of Building Engineering ; Volume 11 , 2017 , Pages 230-235 ; 23527102 (ISSN) Vazirizade, S. M ; Nozhati, S ; Allameh Zadeh, M ; Sharif University of Technology

Elsevier Ltd 2017

Abstract

Localization and quantification of structural damage and estimating the failure probability are key outputs in the reliability assessment of structures. In this study, an Artificial Neural Network (ANN) is used to reduce the computational effort required for reliability analysis and damage detection. Toward this end, one demonstrative structure is modeled and then several damage scenarios are defined. These scenarios are considered as training data sets for establishing an ANN model. In this regard, the relationship between structural response (input) and structural stiffness (output) is established using ANN models. The established ANN is more economical and achieves reasonable accuracy in...

Using decision trees to model an emotional attention mechanism

, Article Frontiers in Artificial Intelligence and Applications ; Volume 171, Issue 1 , Volume 171, Issue 1 , 2008 , Pages 374-385 ; 09226389 (ISSN); 9781586038335 (ISBN) Zadeh, S. H ; Bagheri Shouraki, S ; Halavati, R ; Sharif University of Technology

IOS Press 2008

Abstract

There are several approaches to emotions in AI, most of which are inspired by human emotional states and their arousal mechanisms. These approaches usually use high-level models of human emotions that are too complex to be directly applicable in simple artificial systems. It seems that a new approach to emotions, based on their functional role in information processing in mind, can help us to construct models of emotions that are both valid and simple. In this paper, we will try to present a model of emotions based on their role in controlling the attention. We will evaluate the performance of the model and show how it can be affected by some structural and environmental factors. © 2008 The...