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Questions tagged [convolution]

Convolution is a function-valued operation on two functions $f$ and $g$: $\int _{-\infty }^{\infty }f(\tau )g(t-\tau )d\tau$. Often used for obtaining the density of a sum of independent random variables. This tag should also be used for the inverse operation of deconvolution. DO NOT use this tag for convolutional neural networks.

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How should I go about completely decorrelating a digital signal? [closed]

So I'm working on real time signal compression, and I need to come up with the best convolution to minimize the entropy of incoming data (which I will then compress), which I understand is achieved by ...
2 False's user avatar
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1 answer
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Uniform distribution over a triangle

Problem Consider a triangle $T$ with vertices $V_1,V_2,V_3 \in \mathbb{R}^2$ and let \begin{equation*}\begin{aligned} y&=z+v\\ v&\sim\mathcal{N}(0, R)\\ z&\sim\mathcal{U}(T) \end{aligned}\...
matteogost's user avatar
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40 views

Uniform density over 2 segments [duplicate]

Background Let $V_1, V_2 \in \mathbb{R}^2$ be the vertices of a segment and let $z$ be uniformly distributed over that segment. Now consider the random vector \begin{equation*} \begin{aligned} y&=...
matteogost's user avatar
3 votes
1 answer
95 views

Convolution with a pathological distribution

Problem definition Consider the following random bivariate vector \begin{equation} \begin{aligned} y&=z+v \\ z&\sim p_z(z;c) \\ v&\sim p_v(v) \end{aligned} \end{equation} where $p_z$ ...
matteogost's user avatar
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Why does GAP at the end of FCN for MTSC work?

I have a binary MTSC (Multivariate Time Series Classification) problem where i train a CNN, namely a FCN (or Fully Convolutional Network) to predict class 0 or class 1 based on a multivariate time ...
davva's user avatar
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1 answer
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Percentiles of a distribution of weighted summary statistics

Suppose I have a collection of different independent probability distributions, $\{ P_i(X)\}_{i=1}^N$, each with their own support $I_i$. I know that the $10^{th}$ percentile of a given distribution ...
David G.'s user avatar
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What is the variance of convolution of two random variables?

Consider two random variables $Z$ and $W$. Given the variances of $Z$ and $W$, how can we compute the variance of their convolution $Z \circledast W $? As an example, please consider the case of noise ...
user409495's user avatar
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PDF of difference of uniform distributions [duplicate]

Main questions are in bold but feel free to correct me if I'm wrong somewhere else. As far as possible, I need both intuition and formal explanation. Let $X \sim Uniform(a,b)$ and $Y \sim Uniform(c,d)$...
White1Hun's user avatar
25 votes
4 answers
2k views

Probability that sum of binary variables is even

Let $S_i \in \{0,1\}$, $i=1,\dots,N$ be $N$ independent random binary variables, each taking the value 1 with probability $0 \le p_i \le 1$ (and the value 0 with probability $1-p_i$). I am interested ...
a06e's user avatar
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What is the distribution of a RV with the constant random variable? [duplicate]

For random variables (rv) $X$ and $Y$ on a space $\Omega$: Assume the rv $X\sim f_0$ distributed and $Y(t)=c$ is a constant rv, i.e. $Y\sim \delta(t-c)$ using the $\delta$-distribution as a short ...
Christoph's user avatar
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Why is the maximum path length for convolutional layer $O(n/k)$ in attention is all you need paper?

In the table-1 third row it is being mentioned. Why is it $O(n/k)$? Take for example 1d convolution of 2 over 9 tokens with stride $1$. It won't be $n/k$ or $9/2=4.5$ rather it would be roughly $n-1$ ...
user404316's user avatar
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Inference on latent variable with observation of its convolution with itself

Problem I have an inference problem where the data observed are univariate random numbers whose distribution is obtained as follows. A latent random variable X is first sampled from a parametric ...
Riccardo Buscicchio's user avatar
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Weighted Average of Uniformly Distributed RV [duplicate]

Let $x \sim U[0,1]$ and $y\sim U[0,1]$. Let $z= \omega\, x+ (1-\omega)\,y$, where $\omega\in[0,1]$. The pdf of $z$ is a trapezoidal distribution over $[0,1]$: \begin{equation*} \begin{aligned} f(z)&...
Philipponat's user avatar
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1 answer
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Convolutional Neural Networks - Flattening with multiple feature maps

I have a very simple question about CNNs, which I unfortunately couldn't find an explanation for. Imagine we have a CNN, that has four filters (eg right, left, top, bottom edges) each of those outputs ...
Michal Gally's user avatar
3 votes
1 answer
118 views

How to obtain the last convolutional layer of a model in torchvision for applying grad cam?

I'm using efficient net b0 from torchvision for training a classifier for cifar10. I would like to apply grad cam for generating saliency maps for explaining the predictions. However, I'm not sure ...
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Empirical Mode Decomposition(EMD) + CNN for time series forecasting

I'm currently working on a time series project, and I intend to employ the EMD+CNN technique for forecasting the output. Upon applying EMD to the training data, I obtained a total of 14 Intrinsic Mode ...
Shahin's user avatar
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CNN regression: output mimic the input test data

I am working on convolutional neural network regression problem using U-Net architecture for computing poisson equations. The input data is particle distribution (rho) and the output is electrical ...
samueljohlal's user avatar
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21 views

Why do causal convolutions require positional encoding for image generation?

I'm following this course on deep learning. In lecture 10.2 (page 23 in the handout for the lecture) causal convolutions are introduced as a method for image generation. A bit later it is said, that ...
Cipollino's user avatar
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Computing an integral that reduces to $\mathbb{P}[X>Y]$

Problem Evaluate $$I=\int_{-\infty}^\infty \frac{e^{-\frac{1}{2}\left(\frac{x-\mu)}{\sigma} \right)^2}}{\sigma \sqrt{2 \pi}}\frac{1}{1+e^{-x}}\, \mathrm{d}x$$ My attempt Now the first part of the ...
Bhoris Dhanjal's user avatar
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Exact Successor State Distribution for a Pendulum

I want to solve the following problem. Suppose we have a simple pendulum, which follows the differential equation \begin{equation} \dot{x} = f(x) = [x_2, -\sin(x_1)]^T, \text{with } x=[x_1, x_2]^T. \...
Looper's user avatar
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1 answer
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No activation function between two convolutional layers in MUNIT?

I'm reading the code of NVIDIA's MUNIT, the code of the resnet is as follows: ...
James's user avatar
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1 vote
1 answer
157 views

Is it wrong to view convolution as template matching?

I am reading about the convolution operation but I can't see how it can be seen as template matching. Suppose that we convolve the input $\mathbf{X}$: $$ \begin{bmatrix} 1 & 0 & 0 & 0 \\ 0 ...
ado sar's user avatar
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2 votes
1 answer
221 views

Why convolving a function with a Gaussian kernel is the same as adding a Gaussian noise to the input? [duplicate]

I am implementing accelerated Langevin Dynamics (LD) for posterior estimation with prior presented with deep autoregressive network from paper [1]. I have a question about the prior smoothing ...
ane4ka's user avatar
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4 votes
1 answer
127 views

Probability Density of the Sum of Two Un-identical Uniform Random Variables

Let $X$ ~ Uniform$[a,b]$ and $Y$ ~ Uniform$[c,d],$ where $a\le b\le c\le d.$ Find the probability density of $Z = X + Y.$ I know I have to use the convolution formula $$f_Z(z) = \int_{-\infty}^\...
mathboyexpert1010's user avatar
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Cannot apply simple OLS model in the case of low resolution devices resulting in Fourier space convolution

There's a problem which often comes up within my field and doesn't seem to be approachable analytically. Any suggestions or direction towards the class of problems this falls under would be helpful. ...
Seb's user avatar
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1 vote
1 answer
182 views

When is a conditional hazard rate increasing?

Cross posted from Mathoverflow Let $X$ and $Y$ be two random variables such that $X\sim Exp(\lambda)$ and $Y$ have positive support and (strictly) increasing hazard rate $h_Y$. $X$ and $Y$ are ...
Robin_oud's user avatar
3 votes
2 answers
121 views

Convolution of two functions doesn't fit my data as I thought it would

I have simulated a Gaussian curve in 50 bins of data. I have then repeated this many times, drawing the amplitude of the Gaussian from a log-normal distribution. Here are a 10 realizations: (IMAGE 1) ...
user1551817's user avatar
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Estimating the distribution of a sum of two random variables if the family of one of the variables is known

Assume I have a random variable $Y=X_1+X_2$. I want to estimate the distribution $f$ of $Y$ given a sample $y_1,\ldots,y_N$. If this was all that is known about $Y$ the best way would probably be to ...
LiKao's user avatar
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2 votes
0 answers
106 views

Calculating convolution in R [closed]

I am struggling to get the correct answer for the simple calculation of convolution in R. The convolution of $f(t) = e^{-t}$ and $g(t) = \sin(t)$ is: $$ (f * g)(t) = 1/2 \left( e^{-t} + \sin(t) - \cos(...
s5s's user avatar
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0 votes
1 answer
163 views

How to backpropagate transposed convolution?

I'm currently learning Convolutional Neural Networks and am stuck on trying to figure out how to compute gradients in a layer that uses transposed convolution. Also, how do I calculate the gradients ...
Jakob's user avatar
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3 votes
4 answers
667 views

Probability of a given result with multiples of mixed dice with different number of faces

What is the formula to calculate the probability of getting 41 when I throw two 10-sided dice and four 8-sided dice? I’m looking for an algorithm for the general case of throwing multiples of two sets ...
Cel's user avatar
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3 votes
2 answers
224 views

Calculating the distribution of $X-Y$

One can find the distribution of $X+Y$ where $X$ and $Y$ are independent random variables using this formula $$f_{X+Y}(a)=\int_{-\infty}^\infty f_X(a-y) f_Y(y) dy$$ I'm wondering how to adapt this ...
John Davies's user avatar
5 votes
1 answer
75 views

what are the differences between receptive field (RF) and field-of-views (FOV) in DeepLab papers?

I am learning the deeplab models. However, some concepts in the papers made me confused. Receptive field (RF) and field-of-views (FOV) are two concepts mentioned in the Deeplabv1 paper. I know that ...
kevin lee's user avatar
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9 votes
3 answers
375 views

Density of $|t_1 - t_2|$ where $t_1$ and $t_2$ are iid with $P(t) = \alpha e^{-t\alpha}$

I am trying to answer the following question from my quantum mechanics textbook and my probability theory is admittedly rusty (this is not schoolwork as should be clear from my post history on Phys ...
EE18's user avatar
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1 vote
0 answers
67 views

Order Statistics - Percentile Range of Normal Mixture of Normals

Say I have draw N values from a normal distribution [$\mu_1$, $\sigma_1$]. Below are 10 sampled points compared to the normal distribution they're sampled from I then create a normal mixture of ...
Hunty2312's user avatar
4 votes
0 answers
115 views

Distribution closed under convolution and truncation followed by convolution

Let $D(\theta)$ denote an absolutely continuous distribution on $\mathbb{R}$. (The finite dimensional vector $\theta$ collects the parameters of the distribution.) Assume that the p.d.f. of $D(\theta)$...
cfp's user avatar
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1 vote
1 answer
181 views

How can I build a 6D Convolution Layer in a CNN, using R or Python? [closed]

As stated in the title, I would like to build an N-dimensional Convolutional Layer as part of a Convolution Neural Network, without doing dimensionality reduction on my data; because I have multiple ...
David's user avatar
  • 111
0 votes
0 answers
26 views

Unclear Architecture of MNIST Neural Network

I am trying to reproduce a Neural Network trained to detect whether there is a 0-3 digit in an image with another confounding image. The paper I am following lists the corresponding architecture: A ...
Hustler885's user avatar
1 vote
1 answer
82 views

What "Convolution filters along the time axis" means?

Suppose that I have a tensor of height:25 and width:50. Height is my temporal axis, therefore I have a window of 25 time steps. Therefore my input tensor is: I want to extract temporal features / ...
Mas A's user avatar
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1 vote
0 answers
41 views

Relationship between convolutions in neural nets and probabilistic convolution

In probability theory, convolution extends to produce the distribution of the sum of two independent random variables. I've only ever seen this in the context of univariate random variables. However, ...
Victor M's user avatar
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1 vote
0 answers
14 views

Are Class Activated Maps an example of backpropagated Explainable AI?

Class Activated Maps (NOT GradCAM) is listed in van der Velden et al as a back-propagation approach in table 1, but that is not actually true, is it? CAM doesn't use back-propagation in the method, ...
Stani Petrov's user avatar
1 vote
0 answers
23 views

How to calculate how much each error source contributes to an overall accuracy metric?

I am building a model of overall accuracy for a robotic system, I have various error sources from assembly, calibrations, measurements, imaging, for each error I have a PDF of the error it induces on ...
MedicalClown's user avatar
0 votes
2 answers
106 views

How to average multiple non-normal distributions?

I have the following statistics of two independent random variables: First random variable: ...
Hossein's user avatar
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1 vote
0 answers
41 views

Mean conditional on sum

Let $X$ and $Y$ be two random variables. I am interested in how $\mathrm{E}[X | X + Y = z]$ changes as $z$ changes. Intuitively, if $X$ and $Y$ are independent, the conditional mean should be ...
user36357's user avatar
4 votes
3 answers
4k views

How to determine the no of multiplication operations in convolution operation?

Let's say We have an input of size 28×28×192. We apply 32, 5×5 convolution filters with padding "same". How many multiplication operations will be there in total? I know there will be ...
Sushil Khadka's user avatar
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0 answers
65 views

How to take 1000 samples from distribution X and then use MLE to prove they came from distribution X?

I am trying to do: find 1000 points that represent samples from distribution X with parameters $(a,b,c,\ldots, d)$ be guaranteed that the MLEs for those 1000 points are $(a,b,c,\ldots, d)$ with $99\%$...
Alexander Mills's user avatar
0 votes
0 answers
12 views

What is difference between the joint probability distribution and the sum/convolution, of 2 dists? [duplicate]

Google is coming up a bit short when I searched for "joint vs sum random variables". Perhaps someone can provide an authoritative answer to compare and contrast the sum/convolution of 2 ...
Alexander Mills's user avatar
5 votes
2 answers
2k views

Why does a 1D convolution increase the size of the output, while a 2D convolution tends to decrease (such as in a CNN?)

The function np.convolve is a 1D convolution (e.g. when both inputs are 1D). It results in a larger output size. ...
z611's user avatar
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0 votes
1 answer
86 views

Convolution of two multivariate guassian distribution for the posterior predictive distribution

To find the full conditional distribution of $\eta$ for a Gibbs sampling algorithm , I have to show that $$ p(\eta|-) \propto \int N(\eta;\Omega(\Lambda+\Delta^{-1}\mu),\Omega) N(\mu;\hat{\mu},\Delta/\...
Seth22's user avatar
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3 votes
0 answers
136 views

How to incorporate prior knowledge into a CNN?

I'm pretty new to Bayesian inference and machine learning, so I think I'm just lacking the right words to search for a paper that addresses this topic, so here goes: I'm trying to do image ...
amstrudy's user avatar
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