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    Proposing an Empirical Motion-Time Pattern for Human Gaze Behavior in Different Social Situations Using Deep Neural Networks

    , M.Sc. Thesis Sharif University of Technology Tabatabaei Moghaddam, Ramtin (Author) ; Taheri, Alireza (Supervisor) ; Meghdari, Ali (Supervisor)
    Abstract
    A social robot is an artificial intelligence-based system designed for humans and other robots. These robots can be used in various settings. The more closely a robot resembles and behaves like a human, the more attention and popularity it will gain. The aim of this research is to humanize the behavior patterns of the robot, especially its gaze in different social situations. The social situations considered in this study are common in human life. In these situations, the robot should make decisions based on the activities that humans are engaged in. The research consists of three parts that design neural networks using LSTM and Transformers architecture. The first part utilizes data... 

    Short-run process control based on non-conformity degree

    , Article World Congress on Engineering 2010, WCE 2010, London, 30 June 2010 through 2 July 2010 ; Volume 3 , 2010 , Pages 2273-2276 ; 20780966(Online ISSN) ; 9789881821089 (ISBN) Aminnayeri, M ; Torkamani, E. A ; Davodi, M ; Ramtin, F ; IAENG Society of Artificial Intelligence ; Sharif University of Technology
    2010
    Abstract
    Statistical Process Control (SPC) is an approach that uses statistical techniques to monitor the process. The techniques of quality control are widely used in controlling any kinds of processes. One of these processes is the short processes. In short run processes often do not have enough data in each run to produce good estimates of the process parameters. This will cause the reduction of the performance and efficiency of control charts. A common solution to this problem is considering a single machine or process to produce many different parts, or different products. In this paper a new method based on non-conformity degree and fuzzy membership functions has been developed for controlling... 

    Robots’ cooperation for finding a target in streets

    , Article 1st IFIP WG 1.8 International Conference on Topics in Theoretical Computer Science, 26 August 2015 through 28 August 2015 ; Volume 9541 , 2016 , Pages 30-43 ; 03029743 (ISSN) ; 9783319286778 (ISBN) Mehrizi, M. A ; Ghodsi, M ; Tabatabaei, A
    Springer Verlag  2016
    Abstract
    We study the problem of finding a target t from a start point s in street environments with the cooperation of two robots which have a minimal sensing capability; that is, robots do not know any information about the workspace including information on distances, edges, coordinates, angles etc. They just can detect the discontinuities in the visibility region of their location. The robots can detect target point t as soon as it enters their visibility region and have communication peripherals to send messages to each other. Our aim is to minimize the length of the path passed by the robots. We propose an online algorithm for robots such that they move in the workspace and find the target.... 

    Characterization of Warm Mix Asphalt Containing Reclaimed Asphalt Binders

    , M.Sc. Thesis Sharif University of Technology Safazadeh, Faramarz (Author) ; Tabatabaei, Nader (Supervisor)
    Abstract
    Utilization of RAP in HMA reduces the initial costs, conserves natural sources and avoids disposal problems. Aged binder from RAP will have some effects on resultant binder. To date, solvent extraction and recovery is the only method that physically separates the RAP binder from the RAP aggregate for characterization. Time consuming for recovery, altering the physical properties of the recovered asphalt binder like binder hardening and the possibility that Asphalt binder is not completely extracted from the aggregate are the weak points of this method. Addressing the need for non-solvent based RAP binder characterization; procedures for low temperature characterization of RAP binder... 

    Walking in streets with minimal sensing

    , Article Journal of Combinatorial Optimization ; Volume 30, Issue 2 , 2014 , Pages 387-401 ; ISSN: 13826905 Tabatabaei, A ; Ghodsi, M ; Sharif University of Technology
    2014
    Abstract
    We consider the problem of walking a robot in an unknown polygon called “street”, starting from a point (Formula presented.) to reach a target (Formula presented.). The robot is assumed to have minimal sensing capability in a way that cannot infer any geometric properties of the environment, such as its coordinates, angles or distances; but it is equipped with a sensor that can only detect the discontinuities in the depth information (or gaps). Our robot can also locate the target point (Formula presented.) as soon as it enters in robot’s visibility region. In addition, one pebble is assumed to be available to the robot to be used as an identifiable point and to mark any position of the... 

    Characterization of RAP Binder and Warm Mix Asphalt Containing High RAP Percentage and Crumb Rubber

    , M.Sc. Thesis Sharif University of Technology Morsali, Atefeh (Author) ; Tabatabaei, Nader (Supervisor)
    Abstract
    Increased environmental concerns and high oil prices have encouraged highway agencies to maximize the use of recycled materials like Reclaimed Asphalt Pavements (RAP) in pavement construction. However, utilization of RAP has limited to low percentage, generally less than 25%. This is due aged, stiffer, and less strain tolerant asphalt binder in RAP. As the RAP proportion increases, a large amount of the aged binder will be introduced into the mixture. The excessive stiffness of HMA mixture tends to lead to less workable mixture. Studies were conducted to examine the effect of Sasobit on the workablility of high RAP mixtures. The results indicated while the utilization of Sasobit had improved... 

    Study of the Effects of Rrest Time and Loading Time on Viscoplastic Strain of Asphalt Concrtee

    , M.Sc. Thesis Sharif University of Technology Jahangiri, Behnam (Author) ; Tabatabaei, Nader (Supervisor)
    Abstract
    Asphalt concrete exhibits viscoelastic and viscoplastic behavior which is dependent on rate and temperature. To model this behavior, various mechanical modelshave been presented in which total strain, as the response of the applied stress, is decomposed by various researchers to recoverable and permanent strains.Accumulation and expansion of permanent response result in rutting which is a dominant and prevalent distress in hot mixed asphalt (HMA) in hot climates. The available models are not capable of accurately calculate the viscoplastic strain under cyclic loading.
    To close this gap, recovered viscoelastic strain at rest (unloading) period was introduced. This parameter accounted for... 

    Discrete Element Simulation of Creep Behavior in Asphalt Mixtures

    , M.Sc. Thesis Sharif University of Technology Estaji, Mostafa (Author) ; Tabatabaei, Nader (Supervisor)
    Abstract
    Composite nature of asphalt mixtures necessitates a micromechanical scheme which depends on distinctive characteristics of various constitutive phases. In this regard, discrete element method was utilized to predict the creep behavior of asphalt mixtures and strain response in primary, secondary and tertiary stages. In this research, a modified mixture modeling procedure was considered to better simulate permanent deformation response of asphalt mixtures under creep loading. A random distribution of mastic and aggregate particles with respect to a typical dense gradation was implemented to reconstruct cylindrical specimens. A bonding model represented the cohesion effect in mastic... 

    Optimal strategy for walking in streets with minimum number of turns for a simple robot

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Vol. 8881, issue , 2014 , p. 101-112 Tabatabaei, A ; Ghodsi, M ; Sharif University of Technology
    2014
    Abstract
    We consider the problem of walking a simple robot in an unknown street. The robot that cannot infer any geometric properties of the street traverses the environment to reach a target t, starting from a point s. The robot has a minimal sensing capability that can only report the discontinuities in the depth information (gaps), and location of the target point once it enters in its visibility region. Also, the robot can only move towards the gaps while moving along straight lines is cheap, but rotation is expensive for the robot. We maintain the location of some gaps in a tree data structure of constant size. The tree is dynamically updated during the movement. Using the data structure, we... 

    Walking in streets with minimal sensing

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Chengdu ; Volume 8287 LNCS , 2013 , Pages 361-372 ; 03029743 (ISSN); 9783319037790 (ISBN) Tabatabaei, A ; Ghodsi, M ; Sharif University of Technology
    2013
    Abstract
    We consider the problem of walking in an unknown street, starting from a point s, to reach a target t by a robot which has a minimal sensing capability. The goal is to decrease the traversed path as short as possible. The robot cannot infer any geometric properties of the environment such as coordinates, angles or distances. The robot is equipped with a sensor that can only detect the discontinuities in the depth information (gaps) and can locate the target point as soon as it enters in its visibility region. In addition, a pebble as an identifiable point is available to the robot to mark some position of the street. We offer a data structure similar to Gap Navigation Tree to maintain the... 

    CRA based Control of non-minimum phase fractional order systems

    , Article Proceedings of the IEEE International Conference on Control Applications ; 2012 , Pages 855-858 ; 9781467345033 (ISBN) Tabatabaei, M ; Haeri, M ; Sharif University of Technology
    2012
    Abstract
    In this paper the characteristic ratio assignment (CRA) method is employed to control transient response of a class of non-minimum phase fractional order systems. Since fractional order all-pass filter could not be realized, the fractional unstable zeros are converted to integer unstable zeros by multiplying complementary polynomials to numerator and denominator polynomials of system's transfer function. Doing so, the closed loop system would be an integer order all-pass filter multiple an all-pole fractional transfer function determined from CRA method. Computer simulation results are presented to illustrate the performance of the proposed method. m  

    Sensitivity analysis of CRA based controllers in fractional order systems

    , Article Signal Processing ; Volume 92, Issue 9 , September , 2012 , Pages 2040-2055 ; 01651684 (ISSN) Tabatabaei, M ; Haeri, M ; Sharif University of Technology
    Elsevier  2012
    Abstract
    This paper focuses on robust performance analysis of a closed loop fractional order system through a sensitivity approach. The characteristic ratio assignment method is selected to attain a desired closed loop transient response. Then, we compute the sensitivity of such a desired transfer function with respect to its characteristic ratio and we explore its specifications. The relation between the coefficient diagram shape and the relative stability of the closed loop system is discussed. Also, the closed loop poles variations due to the changes in the characteristic ratios are investigated. Finally, we study a pseudo second order process to verify the robust performance of the characteristic... 

    CRA based control of fractional order systems subject to control signal constraint

    , Article International Conference on Control, Automation and Systems ; 2011 , Pages 268-272 ; 15987833 (ISSN) ; 9781457708350 (ISBN) Tabatabaei, M ; Haeri, M ; Sharif University of Technology
    2011
    Abstract
    An approach is proposed to control transient response of fractional order systems with maximum permissible control signal. This goal is achieved using a newly suggested characteristic ratio assignment method. Based on the proposed method, the generalized time constant τ and the characteristic ratios including their pattern, an adjustable parameter β, and the product of two successive characteristic ratios ρ are determined such that predefined level of overshoot and time specification of closed loop step response are obtained while the control signal is confined to a pre assigned maximum magnitude. The raised issue is solved by defining an optimization problem in which the design parameters... 

    Design of fractional order proportional-integral-derivative controller based on moment matching and characteristic ratio assignment method

    , Article Proceedings of the Institution of Mechanical Engineers. Part I: Journal of Systems and Control Engineering ; Volume 225, Issue 8 , December , 2011 , Pages 1040-1053 ; 09596518 (ISSN) Tabatabaei, M ; Haeri, M ; Sharif University of Technology
    2011
    Abstract
    This paper presents a new analytical method to design fractional-order proportional- integral-derivative (PID) controllers. The control parameters are calculated so that the closedloop system approximates a desired transfer function with transient response requirements. This function is determined based on the characteristic ratio assignment method. The control parameters are calculated by matching the first three moments of the closed-loop transfer function with the corresponding values of the desired system. Furthermore, to ensure closed-loop stability the proposed method is improved by using the shifted moments around the crossover frequency. Illustrative examples are given to show the... 

    Characteristic ratio assignment in fractional order systems (case 0 < v ≤ 0.5)

    , Article Transactions of the Institute of Measurement and Control ; Volume 35, Issue 3 , 2013 , Pages 360-374 ; 01423312 (ISSN) Tabatabaei, M ; Haeri, M ; Sharif University of Technology
    2013
    Abstract
    Five different approaches are presented to assign characteristic ratios for commensurate fractional order systems having order in (0,0.5]. Through the indirect methods, a closed-loop or plant transfer function is converted to a commensurate order one with an order greater than 0.5 so that the previously designed CRA method by the authors is applicable. The first method among the proposed direct ones is based on increasing the order of the desired closed-loop transfer function that allows the employment of positive characteristic ratios. In the second method the closed-loop response is sped up by augmenting an appropriate zero. The final method uses negative characteristic ratios to reach the... 

    Path Planning in Unknown Environment with Minimal Sensing

    , Ph.D. Dissertation Sharif University of Technology Tabatabaei, Azadeh (Author) ; Ghodsi, Mohammad (Supervisor)
    Abstract
    In this research, path planning in unknown environment is considered. It is assumed that the robot’s sensors are the only tools to collect information from the scene. Volume of the information gathered from the environment depends on the capability of the sensor. So, a detour from the optimal path is unavoidable. In this research, the basic robot is equipped with a minimal sensing system that only detects the iscontinuities in depth information (gaps). We present some online search strategies that guide such a robot to navigate unknown streets from a start point s to reach a target point t. Then, we empower the robot by adding a compass to patrol more general classes of polygons. We present... 

    Characteristic ratio assignment in fractional order systems

    , Article ISA Transactions ; Volume 49, Issue 4 , October , 2010 , Pages 470-478 ; 00190578 (ISSN) Tabatabaei, M ; Haeri, M ; Sharif University of Technology
    2010
    Abstract
    In this paper the characteristic ratios and generalized time constant are defined for all-pole commensurate fractional order systems. The sufficient condition for stability of these systems in terms of their characteristic ratios is obtained. Also an analytical approach for characteristic ratio assignment (CRA) to have a non-overshooting fast closed loop step response is introduced. The proposed CRA method is then employed to design a fractional order controller. Computer simulation results are presented to illustrate the performance of the CRA based designed fractional order controllers  

    Laboratory Performance Evaluation of Warm Mix Asphalt with Reclaimed Asphalt Pavement

    , M.Sc. Thesis Sharif University of Technology Danaei, Masoud (Author) ; Tabatabaei, Nader (Supervisor)
    Abstract
    Recycled materials have been very much taken into consideration in recent years due to economic issues and the preservation of natural resources. Warm Mix Asphalt (WMA) is also of particular importance due to less energy use in construction and environmental compatibility. This study examines the compressive workability and resistance to low temperature crackings of warm mixt asphalt containing reclaimed asphalt pavement (up to 30% by weight of aggregate). Sasobit was used as an organic additive in 1.5% by weight of bitumen in warm mix asphalt. Two additives of crumb rubber modifiers (9, 15 and 18% by weight of bitumen) and hydrated lime (1.5 and 2% by weight of aggregate) were also used to... 

    Low Temperature Performance Evaluation of Modified Asphalt Binders

    , M.Sc. Thesis Sharif University of Technology Jahanbakhsh, Hamid (Author) ; Tabatabaei, Nader (Supervisor)
    Abstract
    Low temperature cracking is the most important type of asphalt pavement distress that occurs in cold climates. Up until the development of performance grading (PG) based binder specification, there was no irect indication of low temperature suitability of asphalt binders. PG specification was mainly developed for and validated by neat binders.
    With increased use of modified asphalt binders in recent years, some of the limitations and shortcomings of the original PG specifications have surfaced.Considering that low temperature cracking is a fracture failure, it was hypothesized that tests based on the fracture mechanics and fracture energy parameter can lead to better classification of... 

    Facile synthesis of monodisperse thermally immiscible Ag-Ni alloy nanoparticles at room temperature

    , Article Bulletin of Materials Science ; Vol. 37, issue. 6 , 2014 , pp. 1447-1452 Tabatabaei, S ; Sadrnezhaad, S. K ; Sharif University of Technology
    2014
    Abstract
    Ag and Ni are immiscible, mainly due to their large lattice mismatch. This paper reports on their nanoscale formation of solid solution at room temperature by simple reduction reactions which lead to the amorphous Ag-Ni alloy nanoparticles (ANPs) with mono-disperse distribution. Microscopic and spectroscopic studies confirmed dependence of the alloy composition on size of nanoparticles. In the presence of different ligands such as sodium citrate, polyvinyl alcohol and potassium carbonate a mixture of silver oxide and Ag-Ni ANPs was achieved. Stoichiometry of the Ag-Ni ANPs was also found to be strongly dependent on ligands of the reduction reaction and further study shows without any ligand...