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    Validity and size-dependency of cauchy–born hypothesis with Tersoff potential in silicon nano-structures

    , Article Computational Materials Science ; Volume 63 , October , 2012 , PP. 168–177 Khoei, A. R. (Amir Reza) ; Dormohammadi, H. (Hossein) ; Sharif University of Technology
    One of the most popular constitutive rules that correlate the continuum and atomic properties in multi-scale models is the Cauchy–Born (CB) hypothesis. Based on this constitutive law of continuum media, it assumes that all atoms follow the deformation subjected to the boundary of crystal. In this paper, the validity and failure of CB hypothesis are investigated for the silicon nano-structure by comparison of the continuum and atomic properties. In the atomistic level, the stresses and position of atoms are calculated using the molecular dynamics (MD) simulation based on the Tersoff inter-atomic potential. The stresses and strains are compared between the atomistic and continuous media to... 

    The socioeconomic and demographic determinants of crime in Iran (a regional panel study)

    , Article European Journal of Law and Economics ; Volume 32, Issue 1 , 2011 , Pages 99-114 ; 09291261 (ISSN) Keshavarz Haddad, G ; Markazi Moghadam, H ; Sharif University of Technology
    The raising trend both in violent and property crime are of major concern in Iran. Using a panel data modeling (province wide), the paper provides an econometrics assessment of the relationship between crime against properties and violent crimes as functions of deterrent, social, economic and demographic factors in Iran, in the framework of Becker-Ehrlich crime supply theory. The findings indicate that, although deterrence hypothesis is not confirmed for burglary and assault, it explains the variations of murders and threats. Economic factors play key role in burglary and threat explanation, but they do not affect willful murders, however, Literacy explains both murders and threats. Average... 

    Multi-scale modeling of edge effect on band gap offset in polygonal cross-section silicon nanowires

    , Article Computational Materials Science ; Volume 79 , November , 2013 , PP. 262–275 Khoei, A. R. (Amir Reza) ; DorMohammadi, H ; Aramoon, A ; Sharif University of Technology
    The band gap offset is an effect of coordination numbers (CNs) of atom reduction at the edge of transversal cross-section of Silicon nanowires (SiNWs). In this paper, a hierarchical multi-scale technique is developed to model the edge effect on the band gap shift of SiNWs since the geometric effect is dominant in the energy gap due to the appearance of strain in the self-equilibrium state. The multi-scale model is performed based on the molecular dynamics approach and finite element method for the micro- (atomistic) and macro-scale levels, respectively. The Cauchy–Born (CB) hypothesis is used to relate the atomic positions to the continuum field through the deformation gradient. Finally, the... 

    Effects of applying radio frequency identification in supply chain management: An empirical study of manufacturing enterprises

    , Article International Journal of Business Information Systems ; Volume 23, Issue 1 , 2016 , Pages 97-115 ; 17460972 (ISSN) Pesaran Afsharian, S ; Alizadeh, A ; Chehrehpak, M ; Sharif University of Technology
    Inderscience Enterprises Ltd  2016
    Identifying and tracking goods in the supply chain is one of the most important factors influencing supply chain management. This paper is trying to determine the effects of applying radio frequency identification (RFID) to identify items in the supply chain of manufacturing enterprises. To this aim, in this paper, at first, a comprehensive literature review and experts' judgments are employed to identify possible influential factors, and then a questionnaire is conducted for evaluating these factors. This questionnaire filled by about 200 experts of using RFID in manufacturing enterprise. Filled questionnaire used for examination of statistical hypothesis, which examine the impact of this... 

    Gravitational reduction of the wave function based on bohmian quantum potential

    , Article International Journal of Modern Physics A ; Volume 33, Issue 22 , 2018 ; 0217751X (ISSN) Rahmani, F ; Golshani, M ; Jafari, G ; Sharif University of Technology
    In objective gravitational reduction of the wave function of a quantum system, the classical limit of the system is obtained in terms of the objective properties of the system. On the other hand, in Bohmian quantum mechanics the usual criterion for getting classical limit is the vanishing of the quantum potential or the quantum force of the system, which suffers from the lack of an objective description. In this regard, we investigated the usual criterion of getting the classical limit of a free particle in Bohmian quantum mechanics. Then we argued how it is possible to have an objective gravitational classical limit related to the Bohmian mechanical concepts like quantum potential or... 

    Aberrant frequency related change-detection activity in chronic tinnitus

    , Article Frontiers in Neuroscience ; Volume 14 , 2020 Asadpour, A ; Jahed, M ; Mahmoudian, S ; Sharif University of Technology
    Frontiers Media S.A  2020
    Tinnitus is the perception of sound without the occurrence of an acoustic event. The deficit in auditory sensory or echoic memory may be the cause of the perception of tinnitus. This study considered the mismatch negativity (MMN) to investigate the potential difference between and within groups of persons with normal hearing (NH) and tinnitus. Using an auditory multi-feature paradigm to elicit the MMN, this study considered the MMN peak amplitude at two central frequencies for two MMN subcomponents. These central frequencies were 1 and 5 kHz, which the latter was closer to the perceived tinnitus frequency in the group with tinnitus. The deviants were higher frequency, lower frequency, higher... 

    Review of Thermalization in Closed Quantum Systems

    , M.Sc. Thesis Sharif University of Technology Seif, Negar (Author) ; Rezakhani, Ali (Supervisor)
    For a physical system, equilibrium is defined as a state in which the values of macroscopic quantities describing the system do not change in time. We observe systems around us reaching equilibrium every day. Describing such a seemingly simple phenomena has remained as one of the important challenges in theoretical physics. So far, various explanations for thermalization (approach to equilibrium) have been offered within classical and quantum thermodynamics. In classical statistical mechanics, the microcanonical ensemble provides a suitable prediction of the thermal behavior of a closed system. In this ensemble, using ergodic hypothesis and chaos theory one can assume that all microstates... 

    A comprehensive statistical study on daytime surface urban heat island during summer in urban areas, case study: Cairo and its new towns

    , Article Remote Sensing ; Volume 8, Issue 8 , 2016 ; 20724292 (ISSN) Taheri Shahraiyni, H ; Sodoudi, S ; El Zafarany, A ; Abou El Seoud, T ; Ashraf, H ; Krone, K ; Sharif University of Technology
    MDPI AG  2016
    Surface urban heat island (SUHI) is defined as the elevated land surface temperature (LST) in urban area in comparison with non-urban areas, and it can influence the energy consumption, comfort and health of urban residents. In this study, the existence of daytime SUHI, in Cairo and its new towns during the summer, is investigated using three different approaches; (1) utilization of pre-urbanization observations as LST references; (2) utilization of rural observations as LST references (urban-rural difference); and (3) utilization of the SIUHI (Surface Intra Urban Heat Island) approach. A time series of Landsat TM & ETM+ data (46 images) from 1984 to 2015 was employed in this study for... 

    Bayesian hypothesis testing detector for one bit diffusion LMS with blind missing samples

    , Article Signal Processing ; Volume 146 , May , 2018 , Pages 61-65 ; 01651684 (ISSN) Zayyani, H ; Korki, M ; Marvasti, F ; Sharif University of Technology
    Elsevier B.V  2018
    This paper proposes a sparse distributed estimation algorithm when missing data occurs in the measurements over adaptive networks. Two classes of measurement models are considered. First, the traditional linear regression model is investigated and second the sign of the linear regression model is studied. The latter is referred to as one-bit model. We utilize the diffusion LMS strategy, in the proposed methods, where a set of nodes cooperates with each other to estimate a vector model parameter. In both models, it is shown that replacing the missing sample with a simple estimate is equivalent to removing the missing sample from the distributed diffusion algorithm. We consider two cases,... 

    Simultaneous Hypothesis Testing and False Discovery Rate

    , M.Sc. Thesis Sharif University of Technology Shahbazi, Mohammad (Author) ; Alishahi, Kasra (Supervisor)
    The purpose of this thesis is to introduce and review a recent methods in simultaneous hypothesis testing. False discovery rates, Benjamini and Hochberg’s FDR Control Algorithm, is the great success story of the new methodology. Much of what follows is an attempt to explain that success in empirical Bayes terms.The later chapters are at pains to show the limitations of current largescale statistical practice: Which cases should be combined in a single analysis? How do we account for notions of relevance between cases? What is the correct null hypothesis? How do we handle correlations? Some helpful theory is provided in answer, but much of the argumentation is by example, with graphs and... 

    Auxiliary unscented particle cardinalized probability hypothesis density

    , Article 2013 21st Iranian Conference on Electrical Engineering, ICEE 2013, Mashhad ; 2013 ; 9781467356343 (ISBN) Danaee, M. R ; Behnia, F ; Sharif University of Technology
    The probability hypothesis density (PHD) filter has been recently introduced by Mahler as a relief for the intractable computation of the optimal Bayesian multi-target filtering. It propagates the posterior intensity of the random finite set (RFS) of targets in time. Despite serving as a powerful decluttering algorithm, PHD filter still has the problem of large variance of the estimated expected number of targets. The cardinalized PHD (CPHD) filter overcomes this problem through jointly propagating the posterior intensity and the posterior cardinality distribution. Unfortunately, the particle filter implementation of the CPHD filter suffers from lack of an efficient method for boosting its... 

    Solving Simulation Optimization Problems Using Artificial Bee Colony and Ranking and Selection Methods

    , M.Sc. Thesis Sharif University of Technology Firooze, Hamid Reza (Author) ; Akhavan Niaki, Taghi (Supervisor)
    In this thesis the simulation optimization problems are solved by using Artificial Bee Colony (ABC). The main objective is to improve and adapt the ABC algorithm for solving the optimization problems in deterministic and stochastic environments. For solving deterministic problems, directed search in neighborhood and Nelder-Mead algorithm are combined with ABC algorithm to improve the convergence rate and solutions. Moreover; in stochastic environment, hypothesis test and Kim-Nelson (KN) indifference zone ranking and selection procedure are helping bees to produce solutions with better confidence level on the quality of the solution. Results of optimizing an extensive complex benchmark... 

    An Empirical Research on the Task-Induced Involvement Load Hypothesis: A Case for International Learning

    , M.Sc. Thesis Sharif University of Technology Zare, Mousa (Author) ; Jahangard, ALi (Supervisor) ; Salehi, Mohammad (Co-Advisor)
    Laufer and Hulstijn (2001) proposed the Task-Induced Involvement Load Hypothesis stating that in the retention of new words in an incidental context, tasks with higher involvement load will be more effective than tasks with lower involvement load. The present study aimed to examine whether the retention of vocabulary is enhanced with an increase in the amount of task-induced involvement load in an intentional learning environment. Moreover, it was investigated whether proficiency level of learners had a role in the effectiveness of the vocabulary tasks with different involvement loads. Four groups of university students, male and female, participated in the study. They were given a TOEFL... 

    From-Focused Second Language Vocabulary Learning: A Case for Translation and Dictionary Search

    , M.Sc. Thesis Sharif University of Technology Akbari, Somayeh (Author) ; Jahangard, Ali (Supervisor)
    The purpose of the study was four-fold: first to investigate the predictive adequacy of the Task-Induced Involvement Load Hypothesis which contends that higher-load inducing tasks yield better retention rates in incidental learning situations, second, to examine whether type of dictionary search could affect vocabulary retention, third, to investigate the effect of translation direction on retention rate, and finally to determine the most effective tasks. To meet these ends, six groups of EFL learners - all male, aging 19-25, majoring in various fields of engineering sciences were assigned to the study. Each one of the groups performed distinct tasks which were as follow: reading... 

    Covariance Statistic and a Significance Test for Selecting All Active Variables
    in Lasso

    , M.Sc. Thesis Sharif University of Technology Isakhani Mamaghani, Arman (Author) ;
    Testing the significance of the predictor variables and finding an appropriate method for inference on the coefficients is an important question in the sparse linear regression setting. Covariance statistic is a new method that tries to give an answer to this question. This statistic is defined based on lasso fitted values, and when the true model is linear, this statistic has an Exp(1) asymptotic distribution under the null hypothesis (the null being that all truly active variables are contained in the current lasso model). From classical statistics, we have known some methods like chi-squared test for testing the significance of an additional variable between two nested linear models. But... 

    Improving the Performance of Distributed Fusion for PHD Filter in Multi-Object Tracking

    , M.Sc. Thesis Sharif University of Technology Khazaei, Mohammad (Author) ; Jamzad, Mansour (Supervisor)
    The Gaussian mixture (cardinalized) probability hypothesis density (GM-(C)PHD) filter is a closed form approximation of multi-target Bayes filter which can overcome most of multi-target tracking problems. Limited field of view, decreasing cost of cameras and its advances induce us to use large-scale camera networks. Increasing the size of camera networks make centralized networks practically inefficient. On the other hand, scalability, simplicity and low data transmission cost has made distributed networks a good replacement for centralized networks. However, data fusion in distributed network is sub-optimal due to unavailable cross-correlation.Among data fusion algorithms which deal with... 

    On The Weil Conjectures

    , M.Sc. Thesis Sharif University of Technology Rezaee, Fatemeh (Author) ; Jafari, Amir (Supervisor)
    ” The story of the "Weil conjectures" is a marvelous example of mathematical imagination, and one of the most striking instances exhibiting the fundamental unity of mathematics.”In 1949,Andre Weil stated some conjectures on the zeta function of Algebraic varieties over finite fields .These conjectures were analogue of the properties of Riemann zeta function ,in particular Riemann hypothesis.In fact ,Weil built a bridge between Diophantine structure on varieties over finite fields (Counting of rational points on varieties) and cohomological structure of them over the field of complex numbers(topology of variety).In this thesis, first we state Weil’s motivations for these conjectures and state... 

    Evaluating the Performance of Quantitative Trading Strategies in the Gold Coin futures Maket of Iran Merchantile Exchange

    , M.Sc. Thesis Sharif University of Technology Saleh, Armin (Author) ; Bahramgiri, Mohsen (Supervisor)
    Along with the development of electronic exchanges, accessibility to various data streams, increasing computing power, decreasing trading costs, and growing competition in financial investment industry, quantitative trading strategies or quantitative trading rules have developed rapidly in the recent decades. These strategies try to forecast the future price movements of risky assets from the historical market information in algorithmic ways or statistical ways and thus challenge the Efficient Market Hypothesis.
    The increasing attention to these strategies and lack of related empirical studies in the financial markets of Iran, motivate the research in this area. Furthermore, despite its... 

    Distributed binary majority voting via exponential distribution

    , Article IET Signal Processing ; Volume 10, Issue 5 , 2016 , Pages 532-542 ; 17519675 (ISSN) Salehkaleybar, S ; Golestani, S. J ; Sharif University of Technology
    Institution of Engineering and Technology 
    In the binary majority voting problem, each node initially chooses between two alternative choices. The goal is to design a distributed algorithm that informs nodes which choice is in majority. In this study, the authors formulate this problem as a hypothesis testing problem and propose fixed-size and sequential solutions using classical and Bayesian approaches. In the sequential version, the proposed mechanism enables nodes to test which choice is in majority, successively in time. Hence, termination of the algorithm is embedded within it, contrary to the existing approaches which require a monitoring algorithm to indicate the termination. This property makes the algorithm more efficient in... 

    Cooperative abnormality detection in fluidic medium molecular communication

    , Article 2020 Iran Workshop on Communication and Information Theory, IWCIT 2020 ; 26-28 May , 2020 Khaloopour, L ; Mirmohseni, M ; Nasiri Kenari, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    In this paper, we study the problem of cooperative abnormality detection using mobile sensors in a fluidic medium, based on a molecular communication setup. The sensors are injected into the medium to search the environment for the abnormality. To reduce the effects of sensor imperfection, we propose a cooperative scheme where the sensors activate each other by releasing some molecules (i.e., markers), into the medium after they sense an abnormality. A number of fusion centers (FC) are placed at specific locations in the medium, which absorb all sensors arrived at their locations. By observing the states of the received sensors, each FC decides whether an abnormality exists in its...