Loading...
Search for: correlation-coefficients
0.009 seconds
Total 83 records

    Comparison of River Daily Runoff Simulation Results using Time Series and IHACRES Rainfall-runoff Model

    , M.Sc. Thesis Sharif University of Technology Rahsepar Tolouei, Talaye (Author) ; Shamsaei, Abolfazl (Supervisor)
    Abstract
    Hydrologic models are the best tools to reduce hydrological uncertainties in rivers runoff estimation. Considering structure of model and calibration of parameters, there are several approaches to extend. In this study, we try to simulate daily river runoff by using two different approaches and then compare the results of them with each other. In first approach, IHACRES model is used to simulate rainfall- runoff, which is a conceptual model based on rainfall, runoff and evapotranspiration or temperature data. This model uses conceptual part to estimate effective rainfall and also it uses a transformation function to transform effective rainfall to output flow. This model works in daily time... 

    Prediction of Lumbar Muscle Forces Due to Applied Externally Moment and Analaysing Coactivation Between Lumbar Muscles

    , M.Sc. Thesis Sharif University of Technology Khodadad Kani, Hadi (Author) ; Parnianpour, Mohammad (Supervisor) ; Shams Al-Allahi, Mohammad Bagher (Co-Advisor)
    Abstract
    The role of the lumbar muscles in maintaining posture and balancing externally applied loads has been studied for many years.preliminary studies used electromyograpy (EMG) to establish a relationship between trunk posture and muscle ativity.so developing a better undrestanding of the functional role of those muscles. Determination of lumbar muscle forces, will have an important role in reducing low back pain I future.For this reason,reaserchers have done many studies for understanding the resistence and function on the musulosketal system bye using of various protocls and have utilized of various biomechanical models for determining the effects of applied externally loads on lumbar... 

    Estimation of Power Peaking Factor (PPF)Parameter in VVER Reactor Using Soft Computing, Case Study: Bushehr Nuclear Power Plant

    , M.Sc. Thesis Sharif University of Technology Sharifi, Saeed (Author) ; Ghofrani, Mohammad Bagher (Supervisor) ; Moshkbar Bakhshayesh, Khalil (Supervisor)
    Abstract
    operation of a nuclear power plant. Therefore, constant monitoring of the reactor core with reliable methods is important. To monitor the reactor heart, it is necessary to estimate and calculate some parameters, with high speed and accuracy, such as power distribution inside the heart, reactivity feedback coefficients, PPF, DNBR, etc. Analytical methods are often used to calculate these parameters, which in case of failure of the sensors, the calculations will be practically disrupted, and the method used in this research can solve these problems by losing a small amount of accuracy.In this study using real data of Bushehr nuclear power plant (BNPP) and by soft computing methods and... 

    Forecasting the Possibility of Agricultural Drought using Markov Chain Based on Satellite data and Standard Precipitation Index

    , M.Sc. Thesis Sharif University of Technology Kolahdouzan, Mohammad Ehsan (Author) ; Abrishamchi, Ahmad (Supervisor)
    Abstract
    In comparison with flood, drought is a phenomenon that happens gradually and causes significant changes in water resources, environmental and economic damages specially farming. Due to random features of involving factors in occurrence and intensity of drought, it is assumed as a random process. Drought forecast has an important role in water resources management and control. Data validation, in drought forecast, is a matter of utmost importance. In recent years, satellite data is a type of data that has been used. Markov chain has been used here because one of the features of this method is that occurrence of each variable in current stage is dependent on its previous stage. On the other... 

    Short Time Effect of Auxetic Shoe on Kinematics and Kinetics of Vertebral Column During Drop Vertical Jump

    , M.Sc. Thesis Sharif University of Technology Rahmani Dahaghani, Mostafa (Author) ; Nourani, Amir (Supervisor) ; Arjmand, Navid (Supervisor)
    Abstract
    Investigating the influence of shoes on variables of human biomechanics is of a high importance. The purpose of this study was to examine the effect of auxetic Nike Free RN shoe on kinematics and kinetics of human body. It was asked from 11 healthy male to perform drop vertical jump in three conditions: with auxetic Nike Free RN, with conventional shoe and barefoot. 3D Cartesian positions of the markers, which were stuck to the subjects’ bodies, were recoeded using Vicon camera system. Ground reaction force and its center of pressure of each foot captured using two force plates. Moreover, activation of rectus abdominis, longissimus, iliocostalis lomburom and multifidus were recorded using... 

    Vulnerability assessment of urban groundwater resources to nitrate: the case study of Mashhad, Iran

    , Article Environmental Earth Sciences ; Volume 76, Issue 1 , 2017 ; 18666280 (ISSN) Asadi, P ; Ataie Ashtiani, B ; Beheshti, A ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    Groundwater vulnerability assessment of urban areas is a challenging task in the fast trend of urbanization around the globe. This study introduces a new approach for modifying well-known parameters of common vulnerability indexes to adjust them for urban areas. The approach is independent of a specific weighting system. The aquifer of Mashhad city, contaminated by domestic wastewater, is selected as a case in this study. In order to evaluate the aquifer vulnerability due to anthropogenic activities, at first, parameters of depth to groundwater, recharge, land use, and soil are modified based on their basic concepts and their influences on contamination attenuation. Then, the modified... 

    fMRI functional connectivity analysis via kernel graph in Alzheimer’s disease

    , Article Signal, Image and Video Processing ; 2020 Ahmadi, H ; Fatemizadeh, E ; Motie-Nasrabadi, A ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2020
    Abstract
    Functional magnetic resonance imaging (fMRI) is an imaging tool that is used to analyze the brain’s functions. Brain functional connectivity analysis based on fMRI signals often calculated correlations among time series in different areas of the brain. For FC analysis most prior research works generate the brain graphs based on linear correlations, however, the nonlinear behavior of the brain can lower the accuracy of such graphs. Usually, the Pearson correlation coefficient is used which has limitations in revealing nonlinear relationships. One of the proper methods for nonlinear analysis is the Kernel trick. This method maps the data into a high dimensional space and calculates the linear... 

    fMRI functional connectivity analysis via kernel graph in Alzheimer’s disease

    , Article Signal, Image and Video Processing ; Volume 15, Issue 4 , 2021 , Pages 715-723 ; 18631703 (ISSN) Ahmadi, H ; Fatemizadeh, E ; Motie Nasrabadi, A ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    Functional magnetic resonance imaging (fMRI) is an imaging tool that is used to analyze the brain’s functions. Brain functional connectivity analysis based on fMRI signals often calculated correlations among time series in different areas of the brain. For FC analysis most prior research works generate the brain graphs based on linear correlations, however, the nonlinear behavior of the brain can lower the accuracy of such graphs. Usually, the Pearson correlation coefficient is used which has limitations in revealing nonlinear relationships. One of the proper methods for nonlinear analysis is the Kernel trick. This method maps the data into a high dimensional space and calculates the linear... 

    fMRI functional connectivity analysis via kernel graph in Alzheimer’s disease

    , Article Signal, Image and Video Processing ; Volume 15, Issue 4 , 2021 , Pages 715-723 ; 18631703 (ISSN) Ahmadi, H ; Fatemizadeh, E ; Motie-Nasrabadi, A ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    Functional magnetic resonance imaging (fMRI) is an imaging tool that is used to analyze the brain’s functions. Brain functional connectivity analysis based on fMRI signals often calculated correlations among time series in different areas of the brain. For FC analysis most prior research works generate the brain graphs based on linear correlations, however, the nonlinear behavior of the brain can lower the accuracy of such graphs. Usually, the Pearson correlation coefficient is used which has limitations in revealing nonlinear relationships. One of the proper methods for nonlinear analysis is the Kernel trick. This method maps the data into a high dimensional space and calculates the linear... 

    Rapid quantitative elemental analysis using artificial neural network for case study of Isfahan Miniature Neutron Source Reactor

    , Article Journal of Radioanalytical and Nuclear Chemistry ; Volume 331, Issue 11 , 2022 , Pages 4479-4487 ; 02365731 (ISSN) Asgari, A ; Hosseini, S. A ; Sharif University of Technology
    Springer Science and Business Media B.V  2022
    Abstract
    In this study, new method for NAA purposes at 30 kW Isfahan MNSR is suggested. An algorithm based on ANN is proposed to quantitatively predict the unknown elements with no need standard sample. A three-layer feed-forward ANN with back-propagation algorithm has been used to determine concentration of selenium and fluorine in Multiple Sclerosis patients and healthy people blood samples. Predicted concentration of elements show good agreement between new method and experiment results. The correlation coefficient between the experimentally determined and predicted values are 0.99104 and 0.99364, respectively. This method is a rapid and precise approach for elemental analysis. © 2022, Akadémiai... 

    Fast correlation attacks on the summation generator

    , Article Journal of Cryptology ; Volume 13, Issue 2 , 2000 , Pages 245-262 ; 09332790 (ISSN) Golić, J. D ; Salmasizadeh, M ; Dawson, E ; Sharif University of Technology
    Springer New York  2000
    Abstract
    Abstract. The linear sequential circuit approximation method for combiners with memory is used to find mutually correlated linear transforms of the input and output sequences in the well-known summation generator with any number of inputs. It is shown that the determined correlation coefficient is large enough for applying a fast correlation attack to the output sequence to reconstruct the initial states of the input linear feedback shift registers. The proposed attack is based on iterative probabilistic decoding and appropriately generated low-weight parity-checks. The required output sequence length and the computational complexity are both derived. Successful experimental results for the... 

    Introducing a response-based duration metric and its correlation with structural damages

    , Article Bulletin of Earthquake Engineering ; Volume 17, Issue 11 , 2019 , Pages 5987-6008 ; 1570761X (ISSN) Mashayekhi, M ; Harati, M ; Ashoori Barmchi, M ; Estekanchi, H. E ; Sharif University of Technology
    Springer Netherlands  2019
    Abstract
    This study proposes a response-based parameter for strong motion duration which is computed for structures and is the total time they are nonlinear during an earthquake. Correlation between structural response and duration for structures, subjected to a set of spectrum matched ground motions, is employed to examine the efficiency of the proposed method. The spectral matching procedure ensures that the influence of amplitude and frequency content of motions on structural response variability is significantly removed. Four concrete building type systems are studied and correlation coefficients of structural response with the proposed duration definition are examined. Comparison of the proposed... 

    Feasibility of imperialist competitive algorithm to predict the surface settlement induced by tunneling

    , Article Engineering with Computers ; 2018 ; 01770667 (ISSN) Tashayo, B ; Behzadafshar, K ; Soltani Tehrani, M ; Afkhami Banayem, H ; Hashemi, M. H ; Taghavi Nezhad, S. S ; Sharif University of Technology
    Springer London  2018
    Abstract
    Surface settlement is considered as an adverse effect induced by tunneling in the civil projects. This paper proposes the use of the imperialist competitive algorithm (ICA) for predicting the maximum surface settlement (MMS) resulting from the tunneling. For this work, three forms of equations, i.e., linear, quadratic and power are developed and their weights are then optimized/updated with the ICA. The requirement datasets were collected from the line No. 2 of Karaj urban railway, in Iran. In the ICA models, vertical to horizontal stress ratio, cohesion and Young’s modulus, as the effective parameters on the MSS, are adopted as the inputs. The statistical performance parameters such as root... 

    Feasibility of imperialist competitive algorithm to predict the surface settlement induced by tunneling

    , Article Engineering with Computers ; Volume 35, Issue 3 , 2019 , Pages 917-923 ; 01770667 (ISSN) Tashayo, B ; Behzadafshar, K ; Soltani Tehrani, M ; Afkhami Banayem, H ; Hashemi, M. H ; Taghavi Nezhad, S. S ; Sharif University of Technology
    Springer London  2019
    Abstract
    Surface settlement is considered as an adverse effect induced by tunneling in the civil projects. This paper proposes the use of the imperialist competitive algorithm (ICA) for predicting the maximum surface settlement (MMS) resulting from the tunneling. For this work, three forms of equations, i.e., linear, quadratic and power are developed and their weights are then optimized/updated with the ICA. The requirement datasets were collected from the line No. 2 of Karaj urban railway, in Iran. In the ICA models, vertical to horizontal stress ratio, cohesion and Young’s modulus, as the effective parameters on the MSS, are adopted as the inputs. The statistical performance parameters such as root... 

    Re-construction of the shut-down PM10 monitoring stations for the reliable assessment of PM10 in Berlin using fuzzy modelling and data transformation

    , Article Environmental Monitoring and Assessment ; Volume 189, Issue 3 , 2017 ; 01676369 (ISSN) Taheri Shahraiyni, H ; Sodoudi, S ; Kerschbaumer, A ; Cubasch, U ; Sharif University of Technology
    Springer International Publishing  2017
    Abstract
    A dense monitoring network is vital for the reliable assessment of PM10 in different parts of an urban area. In this study, a new idea is employed for the re-construction of the 20 shut-down PM10 monitoring stations of Berlin. It endeavours to find the non-linear relationship between the hourly PM10 concentration of both the still operating and the shut-down PM10 monitoring stations by using a fuzzy modelling technique, called modified active learning method (MALM). In addition, the simulations were performed by using not only raw PM10 databases but also log-transformed PM10 databases for skewness reduction. According to the results of hourly PM10 simulation (root mean square error about... 

    Improving data protection in BSS based secure communication: mixing matrix design

    , Article Wireless Networks ; Volume 27, Issue 7 , 2021 , Pages 4747-4758 ; 10220038 (ISSN) Aslani, M. R ; Shamsollahi, M. B ; Nouri, A ; Sharif University of Technology
    Springer  2021
    Abstract
    Abstract: In this paper, a secure and efficient Blind Source Separation (BSS) based cryptosystem is presented. The use of BSS in audio and image cryptography in wireless networks has attracted more attention. A BSS based cryptosystem consists of three main parts: secret data, secret keys, and mixing matrix. In this paper, we propose a new design to create a proper mixing matrix in BSS based cryptosystem. We offer a mathematical criterion to select mixing matrix elements before encryption. The proposed criterion gives a simple way to attach the secret sources to keys, which makes source separation very hard for the adversary. Versus, we show that using the random mixing matrix can lead to... 

    Correlation between trunk-pelvis inter-segmental coordination parameters during walking and disability level in chronic low back pain patients

    , Article Journal of Biomedical Physics and Engineering ; Volume 8, Issue 2 , 2018 , Pages 193-202 ; 22517200 (ISSN) Ebrahimi, S ; Kamali, F ; Razeghi, M ; Haghpanah, A ; Sharif University of Technology
    Shiraz University of Medical Sciences  2018
    Abstract
    Background: Chronic low back pain (CLBP) disability has been particularly frustrating because its treatment has been a great therapeutic challenge. Disability has been suggested to depend on different factors that should be found and considered in the medical management. The inter-segmental coordination is often impaired in CLBP subjects; however, to the best of our knowledge, there is no evidence about the relationship between the existence of coordination problems and disability in CLBP patients. Objective: To evaluate the correlation between sagittal plane trunk-pelvis intersegmental coordination parameters during walking and disability level in CLBP patients. Methods: Kinematic data were... 

    Design and evaluation of a novel triaxial isometric trunk muscle strength measurement system

    , Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 223, Issue 6 , 2015 , Pages 755-766 ; 09544119 (ISSN) Azghani, M. R ; Farahmand, F ; Meghdari, A ; Vossoughi, G ; Parnianpour, M ; Sharif University of Technology
    SAGE Publications Ltd  2015
    Abstract
    Maximal strength measurements of the trunk have been used to evaluate the maximum functional capacity of muscles and the potential mechanical overload or overuse of the lumbar spine tissues in order to estimate the risk of developing musculoskeletal injuries. A new triaxial isometric trunk strength measurement system was designed and developed in the present study, and its reliability and performance was investigated. The system consisted of three main revolute joints, equipped with torque sensors, which intersect at L5 - S1 and adjustment facilities to fit the body anthropometry and to accommodate both symmetric and asymmetric postures in both seated and standing positions. The dynamics of... 

    A new deep convolutional neural network design with efficient learning capability: Application to CT image synthesis from MRI

    , Article Medical Physics ; Volume 47, Issue 10 , 2020 , Pages 5158-5171 Bahrami, A ; Karimian, A ; Fatemizadeh, E ; Arabi, H ; Zaidi, H ; Sharif University of Technology
    John Wiley and Sons Ltd  2020
    Abstract
    Purpose: Despite the proven utility of multiparametric magnetic resonance imaging (MRI) in radiation therapy, MRI-guided radiation treatment planning is limited by the fact that MRI does not directly provide the electron density map required for absorbed dose calculation. In this work, a new deep convolutional neural network model with efficient learning capability, suitable for applications where the number of training subjects is limited, is proposed to generate accurate synthetic computed tomography (sCT) images from MRI. Methods: This efficient convolutional neural network (eCNN) is built upon a combination of the SegNet architecture (a 13-layer encoder-decoder structure similar to the... 

    The highest inhibition coefficient of phenol biodegradation using an acclimated mixed culture

    , Article Water Science and Technology ; Volume 73, Issue 5 , 2016 , Pages 1033-1040 ; 02731223 (ISSN) Mohseni, M ; Sharifi Abdar, P. S ; Borghei, S. M ; Sharif University of Technology
    IWA Publishing  2016
    Abstract
    In this study a membrane biological reactor (MBR) was operated at 25±1 °C and pH = 7.5±0.5 to treat synthetic wastewater containing high phenol concentrations. Removal efficiencies of phenol and chemical oxygen demand (COD)were evaluated at four various hydraulic retention times (HRTs) of 24, 12, 8, and 4 hours. The removal rate of phenol (5.51 kg-Phenol kg-VSS-1 d-1), observed at HRT of 4 h,was the highest phenol degradation rate in the literature.According toCODtests, therewere no significant organic matter in the effluent, and phenol was degraded completely by mixed culture. Substrate inhibition was calculated from experimental growth parameters using the Haldane, Yano, and Edward...