Loading...
Search for:
regression-analysis
0.013 seconds
Total 258 records
, M.Sc. Thesis Sharif University of Technology ; Shafahi, Yousof (Supervisor) ; Tabatabaei, Nader (Supervisor)
Abstract
Fatigue is one of the most common failure modes that reduce the structural integrity of asphalt pavements. Dynamic tests are used as fatigue performance indicators for asphalt mixture. However, these tests are expensive and require special equipment and set up. At this research, the main goal is to develop a fuzzy model which is more efficient than the existing regression model for prediction of the fatigue life. A database from the available data from various research was compiled. For each model, a comparison between Fuzzy and regression output by actual outputs was done and it was seen that the fuzzy modeling can predict fatigue life very closely. Finally, the required software for this...
The Influence of Information Presentation and Risk Attitude on Asset Allocation in Financial Markets
, M.Sc. Thesis Sharif University of Technology ; Akhavan Niaki, Taghi (Supervisor)
Abstract
In this work, effects of information aggregation on risk attitude of Iranian individuals is being studied through two experiments. In these experiments a risk-free asset with a guaranteed revenue and a risky asset is introduced to each individual. Then the individual has to allocate a certain amount of money between two assets. In both experiments three treatments of control, separation and aggregation are defined in a way that the degree of information aggregation increases respectively. Given the specific treatment assigned to each individual, complementary information is presented, in orderto finalize the decision. Next a financial market simulation for a five year horizon is conducted to...
Evaluation and Modeling of Queue Length Resulting from Shock Waves in Freeway Work Zone Areas
, M.Sc. Thesis Sharif University of Technology ; Nassiri, Habibollah (Supervisor)
Abstract
Highway work zone is one of the important factors that create long queues and Delays, increase air population, fuel consumption, and road accident. Since in this zones, one and two or sometimes three lanes may be closed, more careful evaluation of the causes of queue formation seems necessary. The purpose of this research was to develop a method to estimate queue length at work zone in rural freeways, based on its traffic flow characteristics. In this study, traffic data from three work zone locations in Karaj-Qazvin freeway was collected. Results of different modeling show that platooning arrival of vehicles at work zone, increase in percentage of heavy vehicles, high variation of speed and...
Analytical Solution of the Swirl Flow in Combustion Chamber of a Hybrid Rocket Engine
, M.Sc. Thesis Sharif University of Technology ; Farahani, Mohammad (Supervisor) ; Rezayi, Hadi ($item.subfieldsMap.e)
Abstract
Hybrid engines are one of a variety of chemical propulsion systems that have been given special attention in recent years by various industries such as space and defense. The most important reasons for considering this type of system are its high safety, its affordable price compared with liquid fuel propulsion systems, the possibility of switching on and off and changing thrust. This system has a lot of disadvantages as well. This system cannot meet all the needs of different industries due to the low regression rate and, consequently, the limitation of the operating range, thrusts and special impulse. As a result, increasing the fuel regression rate in these engines can greatly expand...
How News Affect the Value of Bitcoin
, M.Sc. Thesis Sharif University of Technology ; Talebian, Masoud (Supervisor) ; Hajizadeh, Iman (Co-Supervisor)
Abstract
This research investigates the impact of Bitcoin and cryptocurrency news along with macroeconomic and financial indicators, on Bitcoin price fluctuations for two years (May 2016-2018). The reason for this examination is due to high variations of Bitcoin price in the late 2017 and beginning of 2018, while academic research focusing on Bitcoin price are mostly conducted before 2017. Findings show that the number of news with positive and negative contexts, and news related to cryptocurrency technology have a direct relationship with Bitcoin price change. The other result shows that among news concentrated on Bitcoin, the most effective is regarding adverse incidents, famous people concerns and...
Controlling the False Discovery Rate Via Knockoffs
, M.Sc. Thesis Sharif University of Technology ; Haji MirSadeghi, Mir Omid (Supervisor)
Abstract
In many fields of science, we observe a response variable together with a large number of potential explanatory variables, and would like to be able to discover which variables are truly associated with the response. At the same time, we need to know that the false discovery rate (FDR)—the expected fraction of false discoveries among all discoveries—is not too high, in order to assure the scientist that most of the discoveries are indeed true and replicable. This paper introduces the knockoff filter, a new variable selection procedure controlling the FDR in the statistical linear model whenever there are at least as many observations as variables. This method achieves exact FDR control in...
Vibration transfer path analysis and path ranking for NVH optimization of a vehicle interior
, Article Shock and Vibration ; Vol. 2014, issue , 2014 ; ISSN: 10709622 ; Durali, M ; Sharif University of Technology
Abstract
By new advancements in vehicle manufacturing, evaluation of vehicle quality assurance has got a more critical issue. Today noise and vibration generated inside and outside the vehicles are more important factors for customers than before. So far several researchers have focused on interior noise transfer path analysis and the results have been published in related papers but each method has its own limitations. In present work, the vibration transfer path analysis and vibration path ranking of a car interior have been performed. As interior vibration is a source of structural borne noise problem, thus, the results of this research can be used to present the structural borne noise state in a...
A genetic algorithm for solving fuzzy shortest path problems with mixed fuzzy arc lengths
, Article Mathematical and Computer Modelling ; Volume 57, Issue 1-2 , January , 2013 , Pages 84-99 ; 08957177 (ISSN) ; Mahdavi, I ; Mahdavi Amiri, N ; Tajdin, A ; Sharif University of Technology
2013
Abstract
We are concerned with the design of a model and an algorithm for computing the shortest path in a network having various types of fuzzy arc lengths. First, a new technique is devised for the addition of various fuzzy numbers in a path using α-cuts by proposing a least squares model to obtain membership functions for the considered additions. Due to the complexity of the addition of various fuzzy numbers for larger problems, a genetic algorithm is presented for finding the shortest path in the network. For this, we apply a recently proposed distance function for comparison of fuzzy numbers. Examples are worked out to illustrate the applicability of the proposed approach
Self-organization of developing embryo using scale-invariant approach
, Article Theoretical Biology and Medical Modelling ; Volume 8, Issue 1 , 2011 ; 17424682 (ISSN) ; Tiraihi, M ; Tiraihi, T ; Sharif University of Technology
2011
Abstract
Background: Self-organization is a fundamental feature of living organisms at all hierarchical levels from molecule to organ. It has also been documented in developing embryos. Methods. In this study, a scale-invariant power law (SIPL) method has been used to study self-organization in developing embryos. The SIPL coefficient was calculated using a centro-axial skew symmetrical matrix (CSSM) generated by entering the components of the Cartesian coordinates; for each component, one CSSM was generated. A basic square matrix (BSM) was constructed and the determinant was calculated in order to estimate the SIPL coefficient. This was applied to developing C. elegans during early stages of...
Innovative performance of Iranian knowledge-based firms: Large firms or SMEs?
, Article Technological Forecasting and Social Change ; May , 2016 ; 00401625 (ISSN) ; Bagheri Nasrabadi, M ; Yazdi, N ; Babakhan, A. R ; Sharif University of Technology
Elsevier Inc
2016
Abstract
The debate over innovativeness of large firms and SMEs, which was bolded by Schumpeter, still continues under mixed empirical evidences. There are several implications for this debate including policy orientation in support of large firms or SMEs. But there is a scarce of studies in developing countries and no such study in Iran yet. The present study has explored the proportionality of increase of innovation activity versus firm size within 522 Iranian knowledge-based firms categorized in 9 industries. Innovation activity was measured by R&D expenditure while firm size stood for number of employees. Using log-log regression in the first phase, it was found that R&D expenditure confirms a...
Improving reliability in multistage processes with autocorrelated observations
, Article Quality Technology and Quantitative Management ; Volume 12, Issue 2 , 2015 , Pages 143-157 ; 16843703 (ISSN) ; Aghaie, A ; Shahriari, H ; Akhavan Niaki, S. T ; Sharif University of Technology
Abstract
Multistage process surveillance is considered to effectively improve the product reliability in manufacturing or service operations. To this end, the process output is commonly inspected under specific conditions and the values of the reliability-related quality characteristic are measured. However, in some cases, the observations from the process output are autocorrelated. This brings about the situation where the use of existing monitoring schemes is futile. Therefore, a class of survival analysis regression models called the proportional hazards (PH) model has been modified to justify the effect of cascade property in line with the autocorrelation issue. Subsequently, three monitoring...
Pitch extraction using dyadic wavelet transform and modified higher order moment
, Article International Conference on Communication Technology Proceedings, ICCT, 11 November 2010 through 14 November 2010, Nanjing ; 2010 , Pages 833-836 ; 9781424468690 (ISBN) ; Ghorshi, S ; Mortazavi, M ; Sepehrband, F ; Sharif University of Technology
2010
Abstract
Pitch detection is the process of determining the period of the vocal cords closure or in another word the time duration of one glottal closed, open and returning phase. Dyadic wavelets transform (DyWT) and modified higher order moment, which is based on the autocorrelation function, are two pitch detection methods. DyWT is an accurate pitch detection method, however it has less accuracy compared to modified higher order moment. On the other hand modified higher order moment has high computational complexity and is time consuming. In this paper, we propose a pitch detection method based on DyWT which has use modified higher order moment. Modified higher order moment is applied only in some...
An experimental investigation on the bridge effect in sound produced by Setar
, Article 2009 ASME International Mechanical Engineering Congress and Exposition, 13 November 2009 through 19 November 2009 ; Volume 15 , 2010 , Pages 491-495 ; 9780791843888 (ISBN) ; Arzanpour, S ; Alghassi, H ; Behzad, M ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
Abstract
This study aims to evaluate the amount of energy transfers through the bridge in Setar, a Persian long-necked lute, Stringed musical instruments are among the most complicated acoustical systems. When the string is plucked, its vibration distributes into the entire vibrating system (i.e. body, string, air enclosure) and produces sound. The resultant sound consists of three parts: the first is the string's direct sound; the second is that part of sound-box vibration being excited by string's direct sound, and the third is the part of sound-box vibration being excited by string force passing through bridge. The last part believed to have the major share and the others have minor effect. For...
Higher order spectral regression discriminant analysis (HOSRDA): a tensor feature reduction method for ERP detection
, Article Pattern Recognition ; Volume 70 , 2017 , Pages 152-162 ; 00313203 (ISSN) ; Shamsollahi, M. B ; Hajipour Sardouie, S ; Sharif University of Technology
Abstract
Tensors are valuable tools to represent Electroencephalogram (EEG) data. Tucker decomposition is the most used tensor decomposition in multidimensional discriminant analysis and tensor extension of Linear Discriminant Analysis (LDA), called Higher Order Discriminant Analysis (HODA), is a popular tensor discriminant method used for analyzing Event Related Potentials (ERP). In this paper, we introduce a new tensor-based feature reduction technique, named Higher Order Spectral Regression Discriminant Analysis (HOSRDA), for use in a classification framework for ERP detection. The proposed method (HOSRDA) is a tensor extension of Spectral Regression Discriminant Analysis (SRDA) and casts the...
A joint dictionary learning and regression model for intensity estimation of facial AUs
, Article Journal of Visual Communication and Image Representation ; Volume 47 , 2017 , Pages 1-9 ; 10473203 (ISSN) ; Fatemizadeh, E ; Mahoor, M. H ; Sharif University of Technology
Abstract
Automated intensity estimation of spontaneous Facial Action Units (AUs) defined by Facial Action Coding System (FACS) is a relatively new and challenging problem. This paper presents a joint supervised dictionary learning (SDL) and regression model for solving this problem. The model is casted as an optimization function consisting of two terms. The first term in the optimization concerns representing the facial images in a sparse domain using dictionary learning whereas the second term concerns estimating AU intensities using a linear regression model in the sparse domain. The regression model is designed in a way that considers disagreement between raters by a constant biasing factor in...
Lateral dispersion in deflected emergent aquatic canopies
, Article Environmental Fluid Mechanics ; Volume 19, Issue 4 , 2019 , Pages 833-850 ; 15677419 (ISSN) ; Davari, H ; Shoaei, F ; Sharif University of Technology
Springer Netherlands
2019
Abstract
Understanding the mechanism of dispersion within plants is essential for proper operation of natural and constructed treatment wetlands. Plant deflection induced by the current drag modifies the flow and dispersion within an aquatic canopy. In this study, we look at the effect of the deflection angle of the plants on transverse dispersion. Experiments were carried out in a current flume on an array of inclined solid rods representing a deflected emergent canopy. The stem Reynolds number varied between 90 and 360, normalized stem densities between 0.011 and 0.033, and the inclination angles between 0° and 45°. The plume development was recorded using image processing technique. A special...
Introducing a novel SEMG ANN-based regression approach for elbow motion interpolation
, Article 4th IEEE International Conference on Computer and Communication Systems, ICCCS 2019, 23 February 2019 through 25 February 2019 ; 2019 , Pages 77-80 ; 9781728113227 (ISBN) ; Jahed, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Surface electromyogram (sEMG) signals are extensively used for rehabilitation and control purposes. However due to their intrinsic complexities and intense sensor crosstalk, feature classification and pattern recognition of sEMG signals especially for motion analysis are quite challenging. This study proposes a versatile sEMG Artificial Neural Network based regression approach to evaluate a simple elbow motion with respect to a reference frame. The proposed approach attempts to appropriately interpolate intermediate position angles in an attempt to evaluate and substantiate a continuous motion of the forearm. Results show that based on the proposed algorithm, with a correlation of about 91%...
Robust multi-response surface optimization: a posterior preference approach
, Article International Transactions in Operational Research ; Volume 27, Issue 3 , Volume 27, Issue 3 , 2020 , Pages 1751-1770 ; Moslemi, A ; Akhavan Niaki, S. T ; Sharif University of Technology
Blackwell Publishing Ltd
2020
Abstract
This paper discusses the use of multi-response surface optimization (MRSO) to select the preferred solutions from among various non-dominated solutions (NDS). Since MSRO often involves conflicting responses, the decision-maker's (DM) preference information should be included in the model in order to choose the preferred solutions. In some approaches this information is added to the model after the problem is solved. In contrast, this paper proposes a three-stage method for solving the problem. In the first stage, a robust approach is used to construct a regression model. In the second phase, non-dominated solutions are generated by the ε-constraint approach. The robust solutions obtained in...
Face virtual pose generation using multi resolution subspaces
, Article 2008 International Symposium on Telecommunications, IST 2008, Tehran, 27 August 2008 through 28 August 2008 ; 2008 , Pages 629-633 ; 9781424427512 (ISBN) ; Rabiee, H. R ; Khansari, M ; Sharif University of Technology
2008
Abstract
In this paper a new method for face virtual pose generation is presented. The proposed method uses subspace image representation. The general problem of blurring is addressed by introducing a multi resolution time-frequency analysis to subspace image representation. The training gallery contains face images in two different poses. Undecimated Wavelet Transform is applied on all training face images in first pose and the corresponding images in the second pose to produce image subbands. Then, a new subspace is constructed for each subband in both poses. The mapping between two corresponding subbands of two poses is learnt using linear regression. The resulted mapping matrix is used to...
General regression neural network application to axial compressor performance map
, Article 45th AIAA Aerospace Sciences Meeting 2007, Reno, NV, 8 January 2007 through 11 January 2007 ; Volume 20 , 2007 , Pages 13962-13971 ; 1563478900 (ISBN); 9781563478901 (ISBN) ; Gholamrezaei, M ; Sharif University of Technology
2007
Abstract
General regression neural network (GRNN) is employed to reconstruct the compressor performance map. Two different models are adopted to examine the accuracy of the GRNN technique. The results indicate that the GRNN predictions for both models are very sensitive to the width of the probability a. Further, since the distribution of data is multimodal with large variance differences modes, two solutions are suggested: a locally optimized value for the probability, and the second one is rotated general regression neural network (RGRNN) providing a more accurate result compared to an overall value for the probability. The results show that as the number of samples is reduced to about 70% of the...