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    Active distance-based clustering using k-medoids

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 19 April 2016 through 22 April 2016 ; Volume 9651 , 2016 , Pages 253-264 ; 03029743 (ISSN) ; 9783319317526 (ISBN) Aghaee, A ; Ghadiri, M ; Soleymani Baghshah, M ; Sharif University of Technology
    Springer Verlag  2016
    k-medoids algorithm is a partitional, centroid-based clustering algorithm which uses pairwise distances of data points and tries to directly decompose the dataset with n points into a set of k disjoint clusters. However, k-medoids itself requires all distances between data points that are not so easy to get in many applications. In this paper, we introduce a new method which requires only a small proportion of the whole set of distances and makes an effort to estimate an upperbound for unknown distances using the inquired ones. This algorithm makes use of the triangle inequality to calculate an upper-bound estimation of the unknown distances. Our method is built upon a recursive approach to... 

    Scalable feature selection via distributed diversity maximization

    , Article 31st AAAI Conference on Artificial Intelligence, AAAI 2017, 4 February 2017 through 10 February 2017 ; 2017 , Pages 2876-2883 Abbasi Zadeh, S ; Ghadiri, M ; Mirrokni, V ; Zadimoghaddam, M ; Sharif University of Technology
    Feature selection is a fundamental problem in machine learning and data mining. The majority of feature selection algorithms are designed for running on a single machine (centralized setting) and they are less applicable to very large datasets. Although there are some distributed methods to tackle this problem, most of them are distributing the data horizontally which are not suitable for datasets with a large number of features and few number of instances. Thus, in this paper, we introduce a novel vertically distributable feature selection method in order to speed up this process and be able to handle very large datasets in a scalable manner. In general, feature selection methods aim at... 

    Effect of porosity on buckling and vibrational characteristics of the imperfect GPLRC composite nanoshell

    , Article Mechanics Based Design of Structures and Machines ; Volume 49, Issue 6 , 2021 , Pages 811-840 ; 15397734 (ISSN) Habibi, M ; Mohammadi, A ; Safarpour, H ; Ghadiri, M ; Sharif University of Technology
    Bellwether Publishing, Ltd  2021
    Due to rapid development of manufacturing process, composite materials with porosity have attracted commercially notices in advanced engineering applications. For this regard, buckling and vibrational characteristics of a porous composite cylindrical nanoshell reinforced with GPLs is investigated in this paper. The material properties of piece-wise graphene-reinforced composites (GPLRC) are assumed to be graded in the thickness direction of a cylindrical nanoshell and are estimated using a nanomechanical model. The novelty of our work is including the effects of porosity and GPLRC on natural frequency, critical axial load and critical temperature of the GPLRC cylindrical nanoshell. The... 

    Amperometric sulfide detection using Coprinus cinereus peroxidase immobilized on screen printed electrode in an enzyme inhibition based biosensor

    , Article Biosensors and Bioelectronics ; Volume 35, Issue 1 , 2012 , Pages 297-301 ; 09565663 (ISSN) Savizi, I. S. P ; Kariminia, H. R ; Ghadiri, M ; Roosta Azad, R ; Sharif University of Technology
    In the present work, an amperometric inhibition biosensor for the determination of sulfide has been fabricated by immobilizing Coprinus cinereus peroxidase (CIP) on the surface of screen printed electrode (SPE). Chitosan/acrylamide was applied for immobilization of peroxidase on the working electrode. The amperometric measurement was performed at an applied potential of -150. mV versus Ag/AgCl with a scan rate of 100. mV in the presence of hydroquinone as electron mediator and 0.1. M phosphate buffer solution of pH 6.5. The variables influencing the performance of sensor including the amount of substrate, mediator concentration and electrolyte pH were optimized. The determination of sulfide... 

    Wave propagation analysis of the laminated cylindrical nanoshell coupled with a piezoelectric actuator

    , Article Mechanics Based Design of Structures and Machines ; Volume 49, Issue 5 , 2021 , Pages 640-658 ; 15397734 (ISSN) Habibi, M ; Mohammadi, A ; Safarpour, H ; Shavalipour, A ; Ghadiri, M ; Sharif University of Technology
    Bellwether Publishing, Ltd  2021
    In this article, wave propagation characteristics of a size-dependent laminated composite nanostructure coupled with a piezoelectric actuator (PA) is investigated. In order to consider the effects of small scale, the governing equations of the laminated composite nanostructure coupled with PA are derived using Hamilton’s principle based on the nonlocal strain gradient theory (NSGT). The differential equations of motion are solved with the assistance of the analytical method. Afterward, a parametric study is carried out to investigate the effects of the PA thickness, wave number, angular velocity and the ply angle on the value of phase velocity. The results show that the ply angle plays an... 

    Structure of human errors in tasks of operators working in the control room of an oil refinery unit

    , Article Indian Journal of Science and Technology ; Volume 5, Issue 2 , Feb , 2012 , Pages 2065-2070 ; 09746846 (ISSN) Gholi Nejad, N. S ; Jafari, M. J ; Ghalehnoi, M ; Mehrabi, Y ; Ghadiri, M ; Nikbakht, M ; Sharif University of Technology
    In the present research, human errors existed in tasks of operators working in two control rooms (Northern and Southern control rooms) in the Tehran oil refinery are identified and evaluated. Then, corrective strategies and actions are advised to decrease errors. At first, using hierarchical task analysis (HTA) method, four positions including shift controller, head operators, control room's operators, and outside operators are analyzed. Afterwards, human errors in the considered positions are identified and assessed using technique for retrospective and predictive analysis of cognitive errors (TRACEr). Results present 670 internal errors and 738 external errors in the Northern sector while... 

    Providing a methodology to codify regulations for private parking in tehran city

    , Article International Conference on Transportation and Development 2016: Projects and Practices for Prosperity, 26 June 2016 through 29 June 2016 ; 2016 , Pages 353-364 ; 9780784479926 (ISBN) Khalili, M ; Nickkar, A ; Ghadiri, M ; The Transportation and Development Institute (T and DI) of the American Society of Civil Engineers (ASCE) ; Sharif University of Technology
    American Society of Civil Engineers (ASCE)  2016
    One of the methods for providing private parking is to use the mechanized parking within neighborhoods or housing units that are common in today's world. But, unfortunately, due to lack of appropriate rules and technical, administrative and legal guidelines, this approach has not yet been used. Hence the necessity of investigating and formulating laws, programs and specific criteria for mechanized private parking in terms of legal, technical, traffic, urbanization aspects (location, neighborhood, architecture, building standards and national regulations, economic aspects, etc.) have been a motivation for conducting this study. In this research, after studying and investigating previous...