Search for: sources-identification
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    Pattern recognition analysis of gas chromatographic and infrared spectroscopic fingerprints of crude oil for source identification

    , Article Microchemical Journal ; Volume 153 , 2020 Hashemi Nasab, F. S ; Parastar, H ; Sharif University of Technology
    Elsevier Inc  2020
    In this study, a chemometric strategy was developed for analysis of gas chromatographic (GC) and infrared spectroscopic (FT-IR) fingerprints of nine crude oil samples from the main oil wells of Iran to classify them and to find their origins. In this regard, a fractionation method based on saturated, aromatic, resin, and asphaltene (SARA) test was used. Then, these fractions were analyzed by GC-FID and GC–MS. Also, nine crude oil samples were analyzed by FT-IR. The obtained GC fingerprints were aligned using correlation optimized warping (COW) and auto-scaled, and then analyzed using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Evaluation of PCA scores plot... 

    Variation source identification of multistage manufacturing processes through discriminant analysis and stream of variation methodology: A case study in automotive industry

    , Article Journal of Engineering Research ; Volume 3, Issue 2 , July , 2015 , Pages 96-108 ; 23071885 (ISSN) Bazdar, A ; Baradaran Kazemzadeh, R ; Akhavan Niaki, S. T ; Sharif University of Technology
    University of Kuwait  2015
    Product quality problem is a critical issue for multistage manufacturing processes, especially in continuous production lines whereby quality characteristics are measured at the end of the line. Therefore, it is important to reduce process variation by identifying its sources and eliminating its causes. In this regard, a novel approach, to identify the source of variation in multistage manufacturing processes through integration of the Fisher's linear discriminant analysis and the stream of variation methodology, is proposed. Linear discriminant analysis is used to separate the variation of quality characteristics through the different stages of the manufacturing processes while the stream... 

    Newly desertified regions in Iraq and its surrounding areas: Significant novel sources of global dust particles

    , Article Journal of Arid Environments ; Volume 116 , May , 2015 , Pages 1-10 ; 01401963 (ISSN) Moridnejad, A ; Karimi, N ; Ariya, P. A ; Sharif University of Technology
    Academic Press  2015
    Using the newly developed Middle East Dust Index (MEDI) applied to MODIS satellite data, we consider a relationship between the recent desertified regions, over the past three decades, and the dust source points identified during the period of 2001-2012. Results indicate that major source points are located in Iraq and Syria, and by implementing the spectral mixture analysis on the Landsat TM images (1984 and 2012), a novel desertification map was extracted. Results of this study indicate for the first time that c.a., 39% of all detected source points are located in this newly anthropogenically desertified area. Using extracted indices for Deep Blue algorithm, dust sources were classified... 

    Design and Efficient Implementation of Neural Networks for Solving Graph-based Problems

    , M.Sc. Thesis Sharif University of Technology Mahdipour Araste, Payam (Author) ; Hashemi, Matin (Supervisor)
    The extraordinary ability of the human brain to solve various problems has led scientists to simulate models of the human brain. One of these simulated models is artificial neural networks. Today, the power of artificial neural networks is not overlooked. The ability of artificial neural networks to solve various types of issues led us to use the thesis to solve some of the graph-based problems. Quite accurately, this graph-based problem is a matter of identifying the source of rumor in a network. In many graph networks, whether natural networks such as the network of neurons in the human brain or synthetic ones such as the types of social networks, it is possible that a rumor spreads across... 

    Source Enumeration and Identification in Array Processing Systems

    , Ph.D. Dissertation Sharif University of Technology Yazdian, Ehsan (Author) ; Bastani, Mohammad Hasan (Supervisor)
    Employing array of antennas in amny signal processing application has received considerable attention in recent years due to major advances in design and implementation of large dimentional antennas. In many applications we deal with such large dimentional antennas which challenge the traditional signal processing algorithms. Since most of traditional signal processing algorithms assume that the number of samples is much more than the number of array elements while it is not possible to collect so many samples due to hardware and time constraints.
    In this thesis we exploit new results in random matrix theory to charachterize and describe the properties of Sample Covariance Matrices... 

    Investigating the Propagation Noise in PWRs via Coupled Neutronic and Thermal-Hydraulic Noise Calculations

    , Ph.D. Dissertation Sharif University of Technology Malmir, Hessam (Author) ; Vosoughi, Naser (Supervisor)
    In operating nuclear reactor core, fluctuations (deviations from normal operating conditions) are usually produced and propagated. These fluctuations can be due to control rod vibrations, inlet coolant temperature fluctuations, inlet coolant velocity fluctuations and so on. The induced neutron noise can be detected by in-core neutron detectors. Noise source identifications (such as the type, location and propagating velocity) as well as the calculation of the dynamical parameters (such as moderator temperature coefficient in PWRs and Decay Ratio in BWRs) are of the main applications of the neutron noise analysis in power reactors.
    Investigating the propagation noise in PWRs (specifically... 

    Simulation of Power Reactor Noise Based on Transport Equation

    , Ph.D. Dissertation Sharif University of Technology Bahrami, Mona (Author) ; Vosoughi, Naser (Supervisor)
    In every nuclear reactor core, there are neutron flux fluctuations around the mean value. The neutron noise is the deviation between the time-dependent neutron flux and its expected value, assuming that all process is stationary and ergodic in time. These fluctuations can be caused by the stochastic nature of neutron interactions or mechanical oscillations in the reactor cores. In a reactor working at a high-power level, mechanical fluctuations are the major cause of the fluctuations measured by the detectors. These mechanical vibrations include control rod or fuel rod vibrations, changes in the incoming coolant speed, or changes in the coolant temperature. These perturbations are seen as... 

    Fault diagnosis within multistage machining processes using linear discriminant analysis: a case study in automotive industry

    , Article Quality Technology and Quantitative Management ; Volume 14, Issue 2 , 2017 , Pages 129-141 ; 16843703 (ISSN) Bazdar, A ; Baradaran Kazemzadeh, R ; Akhavan Niaki, S. T ; Sharif University of Technology
    Taylor and Francis Ltd  2017
    Statistical process control provides useful tools to improve the quality of multistage machining processes, specifically in continuous manufacturing lines, where product characteristics are measured at the final station. In order to reduce process errors, variation source identification has been widely applied in machining processes. Although statistical estimation and pattern matching-based methods have been utilized to monitor and diagnose machining processes, most of these methods focus on stage-by-stage inspection using complex models and patterns. However, because of the existence of high rate alarms and the complexity of the machining processes, a surrogate modelling is needed to solve...