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Questions tagged [matlab]

High-level language and interactive programming environment for numerical computing developed by MathWorks.

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8 views

Neural Network for sound classification under Matlab [on hold]

I've been through this Matlab exemple on how to train a simple convolutional neural network for deep learning classification. The dataset used in this exemple is a digit image dataset. I've tried to ...
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0answers
8 views

What does this autocovariance of input data set imply? [on hold]

I wonder what this input covariance means. I feel like this is periodic white noise, but I am not sure. Is there any idea about it? Thank you,
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26 views

Naive Bayes where posterior almost always equals prior (in MATLAB)

I have trained a naive Bayes classifier in MATLAB using fitcnb (description link) and 11 variables, seven of which are numeric (normal) and four of which are categorical ("mvmn" distribution name). I ...
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0answers
8 views

Bayesian network (learn_struct_mwst)

I want to modeling a network with bayesian network. for finding the order i want to use learn_struct_mwst from nbt toolbox in matlab. can anybody help me to use this function? The code that i write ...
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0answers
20 views

possible to identify (2 or more) phases (left/right step) with SVM?

I am new to the field of machine learning and I am trying to create a tool which is able to identify if a left or a right step is performed on a wearable sensor which consists out of 3 sensors (...
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0answers
12 views

How to partition the data into 10 folds using MATLAB [closed]

Dears, I have a data that consists of 21 columns and 2376 rows, and I want to apply 10-fold cross validation, but when I used c = cvpartition (x, 'KFold', 10), it didn't work with me because x is a ...
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0answers
16 views

How to read a very huge data in R? [closed]

I have a file of 219 rows and 25172 columns I use R to open this tab-delimited text file ...
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1answer
49 views

Distribution fitted well but kolmogorov -smirnov test not showing right results? Am I doing it right?

I want to do Kolmogorov -Smirnov test to see whether my data follows a particular distribution or not? When I fitted my data to lognormal distribution it fitted well. But When I am doing ks test, it ...
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0answers
9 views

Fluctuation in mean squared error

I am minimizing mean square error to find vector $f$, with some constraints, and my objective function is \begin{equation} E = f^{T}(R_{aa}-R_{ya}^{T}R_{yy}^{-1}R_{ya}^{})f^{} \end{equation} where $...
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0answers
15 views

Explain the results of the 2-sample Kolmogorov-Smirnov test for two random Gaussian sets of numbers

Suppose I have two sets of random numbers drawn from the Gaussian distribution, $\mathbf{r_1}$ and $\mathbf{r_2}$. I then do a 2-sample Kolmogorov-Smirnov test (KS test) between the two to determine ...
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0answers
28 views

Trying to understand the Kolmogorov-Smirnov test in MATLAB

I have two sets of data, $\mathbf{d_1}$ and $\mathbf{d_2}$ which I want to test to see if they are drawn from the same distribution using the two-sample KS test in MATLAB. My understanding of the KS ...
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0answers
28 views

How to understand the results of nonlinear mixed-effects regression model

I have some data, obtained from 4 different groups. Each repeat is some 4 parametric sigmoid. I need to fit the data to sigmoidal function and answer the question, whether sigmoids are different ...
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0answers
14 views

How to obtain the 1D radial correlation function from the 2D ACF

The two-point correlation function Z2 is defined as the probability that two points separated by a distance r will both lie in ...
0
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1answer
32 views

Algorithmic or structural limitations of space-filling Latin hypercube sampling

I'm new to Latin hypercube sampling, and am trying to understand if the somewhat odd sampling that results from the Matlab function lhsdesign is a limitation of the ...
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0answers
33 views

Logistic regression with negative weights in Matlab

I want to apply a logistic regression to a set of data where observations have been assigned weights depending on their "distance" from {0,1}. Most of the observations have weights within [0,1] range, ...
2
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1answer
40 views

Backpropagation in a logarithmic layer of a regression NN

A "logarithmic neuron" is defined as follows [1]: Which for inputs $\left\{ {{x_1},...,{x_n}} \right\}$ yields an output of $z=\prod\limits_{i = 1..n} {x_i^{{w_i}}}$ (in MATLAB, the activation ...
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0answers
26 views

How to calculate ROC curve for linear discriminant analysis?

I am trying to detect a disease using machine learning algorithms. So there are two classes i.e. either disease or non-disease. At first, I calculated some features (273 features) from the data (400 ...
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0answers
9 views

Skewed t copula model for multivariate

I recently try to write the code of multivariate skewed t copula model. but I do not have the right function of the model. may I ask for the right function or the matlab code of the model? thanks a ...
2
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0answers
38 views

Robust Regression in MATLAB's robustfit: what is the optimal weight function to tackle heteroskedasticity?

I'm currently performing a linear regression analysis and encountered a fair amount of heteroskedasticity. Increases in predicted values go along with decreases in residual variance. Otherwise, the ...
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0answers
15 views

How to calculate image similarity between 2 images using DTV?

I try to implement Differential total variation (DTV) as described in (Wu, Y. et al 2017) or (Li, Y. et al 2015). (Wu, Y. et al 2017) describe DTV as following My DTV Matlab function is ...
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1answer
27 views

Tukey-Kramer or Nemenyi following Friedman

I previously asked a question here after discovering an option by MATLAB to run Tukey-Kramer for multiple comparison multcompare following Friedman test and many ...
2
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0answers
34 views

Why Linear Discriminant analysis in MATLAB and R are producing different results

I am applying manova and lda to my data 12 samples (6 groups with 2 samples in each) and 6 measurements. I used lda form MAS5 package in R and different LDA functions in MATLAB. They all gave me ...
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0answers
17 views

Analysing a 3-D Array

I have a 3-D Array. Where first dimmension represents the amount of systems I am analysing. The second one represents 15 Minute time ticks of a day and the last one temperatures between -7°C and 26°C. ...
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0answers
11 views

Find data in an array above certain percentile for consective days

I have a time series for 10 years of observations. i want to find number of events when the values are above 90th and 80th percentile for consecutive three days.Further i need to find the length of ...
1
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1answer
71 views

How to perform kFold cross validation in Libsvm's precomputed kernel in MATLAB?

I understand that Libsvm provides 'v 10' option for 10-fold cross-validation in...
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0answers
17 views

Additive Regression model, General Additive models

After training an additive regression model such as GAM I get a series of smoothened outputs of splines (for each predictor over all points). Now how will I use this data to apply on a test point, ...
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0answers
11 views

Relationship of confidence interval of parameter estimated and regression bounds

I am using Matlab and have fitted a line of the form y=ax+b using the curve fitting tool box. In the output I get the estimates for ...
2
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0answers
28 views

Why does centering the regressor at a nonzero value improve performance? [closed]

I'm trying to understand why centering myregressor at a nonzero value improves the performance. I always thought that the variance of the feature, and its correlation with the labels, would affect ...
0
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0answers
26 views

What are the implications of asymmetry in the Wilcoxon signed-rank test?

I have samples $a$ and $b$ from pre and post treatment conditions on same participants. The empirical distributions of both these samples are skewed positively. The paired differences $a_i-b_i$ do not ...
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0answers
14 views

How to choose the correct sample and hypothesis test for spatiotemporal observations?

Consider the following scenario: There exist $N=10$ participants in a study. Each participant $i$ is monitored under baseline conditions and later under experiment conditions. That is, the baseline ...
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1answer
23 views

Device grouping using k-means to create clusters with overlapping neiborhoods

I want to use k-means to group (cluster) my devices into overlapping regions. For example I randomly generate the locations of my node devices on an $XY$ plane such as $n_1$ at location $(x_1,y_1)$, $...
1
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0answers
13 views

Performing regression with 1-d response and a 2-d predictor?

I have a dataset I'm trying to figure out how to properly analyze. I'm exploring both how hours spent studying and timing of preparation correlate with test outcomes. The model is as such: response =...
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0answers
15 views

multivariate multiple regression, testing if a variable leads y's at the same time

I have a what I understand to be a multivariate multiple predictive regression. The y's are different variables and I am attempting to see if these are lead by w at the same time. I use the standard ...
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0answers
18 views

Decision tree probability score in MATLAB

How does 'predict' function in MATLAB compute probability scores for predictions for binary classification trees?
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0answers
40 views

Which features to extract from circular shape like blobs for classification of objects

I have circular like objects in raw images (first image attached) and there are three object size of these similar shapes. I want to classify them as small-size, medium-size and large-size using ...
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0answers
14 views

Confidence intervals for estimated means in multimodal Gaussian Mixed model

I am trying to define animal behaviors by using a distribution of turn angles from 0-180 obtained from animal locomotion. My plan is to use the angle distribution to determine a range of angles to use ...
0
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0answers
7 views

Deconvolution of 2 vectors (1 know + 1 unknown)

I am currently trying to deconvolute 2 vectors (a & b) from 1 (c). Actually, I have access to the recorded data of (a) & (c) but not (b). All are signal vs time with signal totally random. I ...
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1answer
46 views

Clustering visited vertex in a graph

I would like to know can anyone introduce me an algorithm to cluster multiple sequence of visited vertices in a graph. For example assume your graph has 6 nodes. following might be 3 different ...
0
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1answer
44 views

Educational purpose :Calculation of sensitivity and specificity from confusion matrix for this example

Consider a case where the number of labelled data as 0 = 1400 and labelled as 1 =100. The data labelled as 0 denote normal operating conditions and data labelled as ...
1
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1answer
76 views

Matlab Classification Learner App vs. own code: Why is there a difference between Leave-One-Person-Out and 10-fold Crossvalidation?

I am trying to find a good model to explain my dataset. The problem is that I want to do leave-one-person-out cross validation which is not available in the Matlab Classification Learner App. So I ...
0
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0answers
23 views

autoencoder parameters effect matlab

i'm new in autoencoders and matlab i'm applying this tutorial https://www.mathworks.com/help/nnet/ug/construct-deep-network-using-autoencoders.html after extrating the features i'm trying to check ...
2
votes
1answer
46 views

How can we determine where the relationship is not linear anymore?

My data look like the following figure. I want to figure out at which point the relationship between y and x starts to become linear. Let’s call this point $x_0$. Let me divide my question into three ...
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1answer
65 views

Why isn't Matlab's Classification Learner the End All? [closed]

After building some machine learning models in Python, R and Matlab, I found the latter's Classification Learner App to be immensely powerful. In the time it took me to build a single model in Python ...
1
vote
1answer
83 views

Regression: very basic questions [closed]

I am about to implement the regression. Since I am analyzing on my own, and have almost zero practical know-how of statistics, I doubt myself a lot (plus the results I have obtained so far look 'weird'...
1
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0answers
30 views

Finding an Analytical Relationship Between Variables

I have a spreadsheet read from a metheorological system with a simple model embedded. I solved the most variables by simple inspection and through related literature, but unfortunately, the literature ...
0
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0answers
46 views

Kernel regression: Bandwidth selection on subsample

I have two columns of data which I sort by size (ascending) of the second column. I now want to execute a kernel regression on the first column (Nadaraya-Watson estimator) and I am interested in only ...
7
votes
1answer
137 views

Confidence bounds for an ECDF

I'm attempting to create an ECDF (and a confidence bound) from data in Python. I can generate the ECDF fairly easily with numpy by sorting and using ...
0
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1answer
35 views

How can I test PCR model?

I'm new to modeling principle component regression. I used MATLAB documentation to see an example on how to do it using the built-in functions. I just want to know how to test the model to try other ...
0
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1answer
86 views

Automatic relevance determination Kernel for GPR in sklearn

I have checked the performance of my model with the different kernel and seems ARD kernels, where each estimator has different length scale performance better than normal kernels. ARD kernels are not ...
0
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0answers
21 views

ARMA / ARMAX with nonlinear cross terms

Assume I have a multi variable ARMAX model. I would like to evaluate the influence of including cross products of the inputs. I could just calculate the cross products and include them as inputs for ...