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    Existence and continuity of differential entropy for a class of distributions

    , Article IEEE Communications Letters ; Volume 21, Issue 7 , 2017 , Pages 1469-1472 ; 10897798 (ISSN) Ghourchian, H ; Gohari, A ; Amini, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    Abstract
    In this letter, we identify a class of absolutely continuous probability distributions, and show that the differential entropy is uniformly convergent over this space under the metric of total variation distance. One of the advantages of this class is that the requirements could be readily verified for a given distribution. © 1997-2012 IEEE  

    How compressible are innovation processes?

    , Article IEEE Transactions on Information Theory ; Volume 64, Issue 7 , 2018 , Pages 4843-4871 ; 00189448 (ISSN) Ghourchian, H ; Amini, A ; Gohari, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    The sparsity and compressibility of finite-dimensional signals are of great interest in fields, such as compressed sensing. The notion of compressibility is also extended to infinite sequences of independent identically distributed or ergodic random variables based on the observed error in their nonlinear $k$ -term approximation. In this paper, we use the entropy measure to study the compressibility of continuous-domain innovation processes (alternatively known as white noise). Specifically, we define such a measure as the entropy limit of the doubly quantized (time and amplitude) process. This provides a tool to compare the compressibility of various innovation processes. It also allows us... 

    Ionic liquid/graphene oxide as a nanocomposite for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase

    , Article Journal of Solid State Electrochemistry ; Volume 17, Issue 1 , January , 2013 , Pages 183-189 ; 14328488 (ISSN) Tasviri, M ; Ghasemi, S ; Ghourchian, H ; Gholami, M. R ; Sharif University of Technology
    2013
    Abstract
    By combination of 1-ethyl-3-methyl immidazolium ethyl sulfate as a typical room temperature ionic liquid (IL) and graphene oxide (GO) nanosheets, a nanocomposite was introduced for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase (GOx). The enzyme on the IL-GO-modified glassy carbon electrode exhibited a quasireversible cyclic voltammogram corresponding to the flavine adenine dinucleotide/FADH2 redox prosthetic group of GOx. At the scan rate of 100 mV s-1, the enzyme showed a peak-to-peak potential separation of 82 mV and the formal potential of -463 mV (vs Ag/AgCl in 0.1 M phosphate buffer solution, pH 7.0). The kinetic parameters of the charge transfer... 

    Erratum to: The Electrochemical study of glucose oxidase on gold_coated magnetic iron oxide nanoparticles (journal of analytical chemistry, (2015), 70, 10, (1254-1260), 10.1134/S1061934815100123)

    , Article Journal of Analytical Chemistry ; Volume 77, Issue 5 , 2022 , Pages 640- ; 10619348 (ISSN) Eskandari, K ; Zarei, H ; Ghourchian, H ; Amoozadeh, S. M ; Sharif University of Technology
    Pleiades journals  2022
    Abstract
    The affiliation and indication of affiliation for author Seyed-Mostafa Amoozadeh should read as follows: e Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran The original article can be found online at https://doi.org/10.1134/S1061934815100123 © 2022, Pleiades Publishing, Ltd  

    Evaluating the Rate of Compressibility of Sparse Stochastic Processes

    , M.Sc. Thesis Sharif University of Technology Ghourchian, Hamid (Author) ; Amini, Arash (Supervisor) ; Aminzadeh Gohari, Amin (Supervisor)
    Abstract
    In most stochastic models with uncountable cardinality of sample space with non-trivial probability measures, the inherent information is infinite. The continuous-valued random variables and continuous-domain random processes are among such objects. Therefore, a fidelity criterion must be defined between the stochastic subject and its estimated version. Although there are some criteria for of stochastic continuous signals, based on quantizing the signal in both time and amplitude domains, we are going to define a criterion which is for stochastic processes in bounded time domain. Next, the criterion will be expressed in general sources perspective and the optimum rate of coding will be... 

    Amine functionalized TiO2 coated on carbon nanotube as a nanomaterial for direct electrochemistry of glucose oxidase and glucose biosensing

    , Article Journal of Molecular Catalysis B: Enzymatic ; Volume 68, Issue 2 , 2011 , Pages 206-210 ; 13811177 (ISSN) Tasviri, M ; Rafiee Pour, H. A ; Ghourchian, H ; Gholami, M. R ; Sharif University of Technology
    2011
    Abstract
    A nano-composite material consisting of amine functionalized TiO 2-coated carbon nanotubes was prepared and used for glucose oxidase (GOx) absorption. The GOx bearing nanomaterial was fixed on a glassy carbon electrode to construct a novel biosensor for glucose determination. The direct electrochemistry of immobilized GOx and its electron transfer parameters at the modified glassy carbon electrode were reported. The apparent heterogeneous electron transfer rate constant (ks) of GOx was estimated to be 3.5 s-1, which is higher than those reported previously. Amperometric detection of glucose resulted in a rapid (3 s) and stable response in the linear concentration range from 1.8 to 266 μM.... 

    On the capacity of a class of signal-dependent noise channels

    , Article IEEE Transactions on Information Theory ; Volume 64, Issue 12 , 2018 , Pages 7828-7846 ; 00189448 (ISSN) Ghourchian, H ; Aminian, G ; Gohari, A ; Mirmohseni, M ; Nasiri Kenari, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    In some applications, the variance of additive measurement noise depends on the signal that we aim to measure. For instance, additive signal-dependent Gaussian noise (ASDGN) channel models are used in molecular and optical communication. Herein, we provide lower and upper bounds on the capacity of additive signal-dependent noise (ASDN) channels. The first lower bound is based on an extension of majorization inequalities, and the second lower bound utilizes the properties of the differential entropy. The lower bounds are valid for arbitrary ASDN channels. The upper bound is based on a previous idea of the authors ('symmetric relative entropy') and is applied to the ASDGN channels. These... 

    Synthesis of Nanocomposites based on Carbon nanotubes and Graphene/Ionic Liquid for Construction of Biosensors

    , Ph.D. Dissertation Sharif University of Technology Tasviri, Mahboubeh (Author) ; Gholami, Mohammad Reza (Supervisor) ; Ghourchian, Hedayatollah (Co-Advisor)
    Abstract
    In this project during 2 sections the synthesis and application of nanomaterials based on carbon nanotubes and graphene oxide for immobilization of Glucose oxide and Horseradish peroxidase enzymes for construction of effective biosensors were investigated. In section 1, we introduce a new nanomaterial in which TiO2-coated carbon nanotubes were functionalized with amine groups (NH2-TiO2-CNTs). This nanomaterial was fixed on a glassy carbon electrode surface and then its ability for direct electron transfer of Glucose oxidase (GOx) and Horseradish peroxidase (HRP) on the modified electrode was investigated. The direct electrochemistry of immobilized GOx and its electron transfer parameters at... 

    Ionic liquid/graphene oxide as a nanocomposite for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase

    , Article Journal of Solid State Electrochemistry ; Vol. 17, Issue 1 , January , 2013 , pp 183-189 ; ISSN: 1432-8488 Tasviri, M (Mahboubeh) ; Ghasemi, S. (Shahnaz) ; Ghourchian, H. (Hedayatollah) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
    2013
    Abstract
    By combination of 1-ethyl-3-methyl immidazolium ethyl sulfate as a typical room temperature ionic liquid (IL) and graphene oxide (GO) nanosheets, a nanocomposite was introduced for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase (GOx). The enzyme on the IL–GO-modified glassy carbon electrode exhibited a quasireversible cyclic voltammogram corresponding to the flavine adenine dinucleotide/FADH2 redox prosthetic group of GOx. At the scan rate of 100 mV s−1, the enzyme showed a peak-to-peak potential separation of 82 mV and the formal potential of −463 mV (vs Ag/AgCl in 0.1 M phosphate buffer solution, pH 7.0). The kinetic parameters of the charge transfer... 

    Horseradish peroxidase immobilization on amine functionalized carbon nanotubes: direct electrochemistry and bioelectrocatalysis

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 37, Number 2 , 2012 , pp. 161-172 Tasviri, M. (Mahboubeh) ; Ghourchian, H. (Hedayatollah) ; Gholami, M. R. (Mohammad Reza) ; Rafieepour, H. A. (Hossain Ali) ; Sharif University of Technology
    2012
    Abstract
    Horseradish peroxidase (HRP) was successfully immobilized on amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2 – TiO2 – CNTs) by a convenient and efficient method. Electrochemical impedance spectroscopy, cyclic voltammetry and amperometry were applied to characterize the HRP/NH2 – TiO2 – CNT nano-composite. These techniques showed that the NH2 – TiO2 – CNTs greatly enhance the electron transfer between HRP and the modified electrode. Owing to the redox reaction of the electroactive centre of HRP, the HRP = NH2 – TiO2 – CNTs modified electrode exhibited a pair of quasi-reversible peaks with a peak-to-peak separation (ΔEp) of 70.6 mV and a formal potential (E 0′) of 367.65 mV... 

    Optimizing Transmisson from Distant Wind Farms

    , M.Sc. Thesis Sharif University of Technology Abdollahi Mansourkhani, Hamid Reza (Author) ; Hosseini, Hamid (Supervisor)
    Abstract
    Wind power is site dependent and is by nature partially dispatchable. Furthermore, good wind sites are far from grid. Due to these problems, and along with the existing limitations in the transmission networks, a comprehensive analysis over an extended time is needed to properly explore all potential wind sites for wind capacity allocation. This problem is computationally expensive and decomposition methods are required to break down this problem. Here Benders decomposition approach is used, which is a popular technique for solving large-scale problems, to decompose the original problem into a master and a subproblem. The master problem is a linear problem, which allocates wind capacity to... 

    Identification of the Set of Single Nucleotide Variants in Genome Responsible for the Differentiation of Expression of Genes

    , M.Sc. Thesis Sharif University of Technology Khatami, Mahshid (Author) ; Rabiee, Hamid Reza (Supervisor) ; Beigi, Hamid (Supervisor)
    Abstract
    Single nucleotide polymorphs, There are changes caused by a mutation in a nucleotide in the Dena sequence. Mononucleotide polymorphisms are the most common type of genetic variation. Some of these changes have little or no effect on cells, while others cause significant changes in the expression of cell genes that can lead to disease or resistance to certain diseases. Because of the importance of these changes and their effect on cell function, the relationships between these changes are also important. Over the past decade, thousands of single disease-related mononucleotide polymorphisms have been identified in genome-related studies. Studies in this field have shown that the expression of... 

    Synthesis & Characterization of Au-HKUST-1 Nanocomposite and Evaluation of Plasmonic Properties of Gold Nanoparticles in this Nanocomposite

    , M.Sc. Thesis Sharif University of Technology Moazzeni, Hamid Reza (Author) ; Madaah Hosseini, Hamid Reza (Supervisor)
    Abstract
    In the past few years, many research works on the controllable integration of metal nanoparticles and metal-organic frameworks were done, since the obtained composite material shows a synergism effect in catalysis and photocatalysis, drug delivery applications, gas, and energy storage, as well as sensing. For the first time, in this study, we employed template-assisted growth to synthesize Au-HKUST-1 Nanocomposite. XRD analysis entirely confirms that employing this strategy in synthesizing Au-HKUST-1 was wholly successful, and the plasmonic properties of this nanostructure were studied via UV-visible spectroscopy. In the course of synthesis, gold nanoparticles with 70nm diameter were... 

    Synthesis of Magnetite (Fe3O4)-Avastin Nanocomposite as a Potential Drug for AMD Treatment

    , M.Sc. Thesis Sharif University of Technology Zargarzadeh, Mehrzad (Author) ; Maddah Hosseini, Hamid Reza (Supervisor) ; Delavary, Hamid (Co-Advisor)
    Abstract
    Age-related macular degeneration (AMD) is the most common cause of vision loss in those aged over 50. There are two main types of AMD, Wet and Dry form. Wet AMD is more severe though more treatable. There are three conventional treatments for AMD including laser therapy, surgery and intravitreal injection of anti-VEGF into the eye. Delivery of drugs to the posterior segment of the eye is still challenging and several implants and devices are currently under investigation for their ability to stimulate the retina, producing visual percepts. The application of intravitreal bevacizumab (Avastin) has expanded tremendously from the time of its introduction into ophthalmic care since 3 years ago.... 

    Detection of Central Nodes in Social Networks

    , Ph.D. Dissertation Sharif University of Technology Mahyar, Hamid Reza (Author) ; Movaghar, Ali (Supervisor) ; Rabiee, Hamid Reza (Supervisor)
    Abstract
    In analyzing the structural organization of many real-world networks, identifying important nodes has been a fundamental problem. The network centrality concept deals with the assessment of the relative importance of network nodes based on specific criteria. Central nodes can play significant roles on the spread of influence and idea in social networks, the user activity in mobile phone networks, the contagion process in biological networks, and the bottlenecks in communication networks. High computational cost and the requirement of full knowledge about the network topology are the most significant obstacles for applying the general concept of network centrality to large real-world social... 

    Cost-Sensitive Classifiers and Their Applications

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Zahra (Author) ; Beigy, Hamid (Supervisor)
    Abstract
    Decision making often has different effects and results with unequal importance. Most of classifiers try to minimize the rate of misclassified instances. These classifiers assume equal costs for different misclassification types. However, this assumption is not true in many real world problems and different misclassification types have different costs. These differences can be applied by introducing the cost in the process of learning. In this manner, total cost of misclassification will be the evaluation metric of classification. In order to apply this metric to the problems, new learning algorithms are needed. Cost-sensitive learning is the related area of machine learning which deals with... 

    Data Stream Classification in Presence of Concept Drift Using Ensemble Learning

    , M.Sc. Thesis Sharif University of Technology Sobhani, Parinaz (Author) ; Beigy, Hamid (Supervisor)
    Abstract
    Traditional classification techniques of machine learning assume that data have stationary distributions. This assumption for recent challenges where tremendous amount of data are generated at unprecedented rates with evolving patterns, is not true anymore. Classification of data streams has become an important area of machine learning, as the number of applications facing these challenges increases. Examples of such data streams applications include text streams, surveillance video streams, credit card fraud detection, market basket analysis, information filtering, computer security, etc. An appropriate method for such problems should adapt to drifting concepts by revising and refining the... 

    Using Transductive Learning Classification in Bioinformatics

    , M.Sc. Thesis Sharif University of Technology Tajari, Hossein (Author) ; Beigy, Hamid (Supervisor)
    Abstract
    Classification is one of the most important problems in machine learning area. Reliable and successful classification is essential for diagnosing patients for further treatment. In many applications such as bioinformatics unlabeled data is abundant and available. However labeling data is much more difficult and expensive to obtain. This dissertation presents a novel transductive approach for the development of robust microarray data classification. The transduction problem is to estimate the value of classification function at the given points in the working set. This contrasts with the standard inductive learning problem of estimating the classification method at all possible values and... 

    Concept Drift Detection in Data Streams Using Ensemble Classifiers

    , M.Sc. Thesis Sharif University of Technology Dehghan, Mahdie (Author) ; Beigy, Hamid (Supervisor)
    Abstract
    Concept drift is a challenging problem in the context of data stream processing. As a result of increasing applications of data streams, including network intrusion detection, weather forecasting, and detection of unconventional behavior in financial transactions; numerous studies have been conducted in the field of concept drift detection. In order to solve the problem of concept drift detection, an ideal method should be able to quickly and correctly identify a variety of changes, adapt quickly to new concepts, in the presence of limitations of memory and processing power. In this thesis, a new explicit concept drift detection method based on ensemble classifiers has been proposed for data... 

    Call Admission Control Schemes in WiMAX Networks

    , M.Sc. Thesis Sharif University of Technology Mokhtari, Zeinab (Author) ; Beigy, Hamid (Supervisor)
    Abstract
    The rapid growth of broadband wireless access (BWA) has increased the demand of new  application  such  as  VoIP,  video  conferencing,  online  gaming  each  of  which  has  different requirement for quality of service. Due to limited bandwidth provided for these networks,  one  of  the  most  important  issues  is  how  effective  we  manage  bandwidth  in  order to support requests. The quality of service is an important indicator of the effective management  of  bandwidth.  Using  mechanisms  of  call  admission  control is  a  commonly  accepted method for balance between quality of service and increase of utilization resource  in  cellular  mobile  networks.  In  fact, ...