Questions tagged [machine-learning]

Machine learning, a branch of artificial intelligence, is the science of getting computer systems to meaningfully act without being explicitly programmed by human.

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Interpolation vs. Neuronal network

I am seeking knowledge from the community. I am solving a transport PDE (conservation of solute mass) using COMSOL. At each Newton-Raphson iteration, I need to update a constant called $Kd$ for some ...
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1answer
46 views

Training accuracy improves but test set accuracy remains the same

I have built an ANN model with 5 hidden layers and 100 nodes in each layer to solve a multilabel classification problem. After the first run, I get a training accuracy of ~66% and a test set accuracy ...
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40 views

Singular Spectrum Analysis Explanation

I need you to help me understand the Singular Spectrum Analysis algorithm. I already read a lot of articles about the subject but they never answered my questions like what is the mathematical reason ...
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92 views

Connection between piecewise linear basis functions and RELU activation function

ReLU activation is defined as follows $$\sigma(x)=\max(0, x).$$ Let's assume that I have deep network of 1 hidden layer, than output from my layer has form $$ f(x)= \sigma(Wx +b), $$ where matrix W ...
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1answer
22 views

Want to make sense of array dimensions in logistic regression algorithms

I am trying to implement a simple logistic regression algorithm from scratch in python (for learning purposes). Every article I've seen online so far presents the following expression for $z$ (...
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1answer
102 views

Artificial neural networks for Temperature prediction

Imagine I want to consider the temperature for a process given several input varibales. The temperature can be anywhere between 400 and 500 K. Consider I have experimental data to train the network ...
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101 views

Are the No Free Lunch Theorems Useful for Anything?

I have been thinking about the No Free Lunch (NFL) theorems lately, and I have a question which probably every one who has ever thought of the NFL theorems has also had. I am asking this question here,...
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3answers
164 views

Optimization of a blackbox function

Let's say that we have an objective function $f(\mathbf x,\mathbf y)$ which has the parameters $\mathbf x=[x_1\ldots x_n]$ and $\mathbf y=[y_1\ldots y_n]$. Here, $\mathbf y$ is a blackbox variable ...
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40 views

What is a performant clustering algorithm for approx 10,000 vectors of approx 30 dimension?

I have a set of real-valed vectors, for example $S = \{v_1, v_2, ..., v_k\}$ $v_i = \begin{pmatrix} age_i \\ height_i \\ weight_i \\ ... \end{pmatrix}$ or whatever. Each vector has on the order of ...
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82 views

Is there any ML solutions for permutations?

In Machine Learning field, is there any work done, or research, or info in general about finding optimal permutations? For eg. to find a number of optimal arrangements of sliced shapes on 2D sheet of ...
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1answer
124 views

Why is FLOP(Floating Point Operations Per Second) mentioned as a specification on every GPU?

Counting FLOP may not be representative of the actual algorithm real world performance but still all the GPU manufacturers mention FLOPS as a metric of Performance on GPU. Is there any way that this ...
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1answer
144 views

Using the PAST algorithm to find eigenvectors

I'm working on trying to extract the eigenvectors from a series of observations from a random variable, by using the PAST algorithm, see e.g. 6.2.3 in this book: Large pdf. I don't understand the ...
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48 views

Update model parameter with new data, discarding old data

I have this dataset, and I am using y = (a * x^n) / (b + x^n) Hill function as the model, where a is the limit of the Hill curve,...
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2answers
189 views

Is there any scalable machine learning tool like molecular dynamics software NAMD?

I work in Molecular dynamics of biomolecules. I am familiar with the software NAMD. We use NAMD in our CPU cluster with the aid of mpirun. Without GPUs can I implement large scale deep learning? ...
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1answer
118 views

Why can't we just use machine learning to select which model to use for a given model?

Suppose you have a classification problem, now what if I implement and train all classification models like logistic regression, KKN, naive Bayes, decision tree or random forest on the training data ...
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2answers
72 views

Using low rank property for maximal/minimal value search (or sorting)

I was thinking about the following problem: Suppose there is a positive semidefinite matrix $X$ of size $n$ (for example, a kernel). Suppose $X$ can be approximated as a low rank matrix, $X\approx ...
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0answers
48 views

The right algorithm to predict from selected data samples [closed]

I'm trying to come up with the right algorithm for a system in which the user enters a few symptoms and the system has to predict or determine the likelihood that a few selected symptoms are ...
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0answers
14 views

Optimizing estimator of composed functions when function is known

Note: This was cross-posted from comp-sci, as I didn't know this community existed! I have a problem which I'm looking to see if there is literature on: Consider three types of actors, a Director, ...
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2answers
97 views

Learning computational science through guided discovery

I am currently trying to get through Pattern Classification by Duda et al (for a course). However, the book seems too dense for me. Pattern recognition seems like a topic that could be better learned ...
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188 views

Generalization error and Sample Complexity estimation for Least Squares

I am wondering how to draw a sample complexity plot similar to the following figure which shows the estimated number of samples to incur no more than 10 percent generalisation error on average for the ...
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124 views

Machine Learning and predictive maintenance

I am looking for a paper or return on experience regarding the use of Machine Learning in predictive maintenance in the context of data center?
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2answers
39 views

How are the outcomes that generated from different predictive models combined to get more accurate predictions?

The simple average is commonly used to combine the predictions out of different predictive models. Apart form the simple average, what are the other methods that can be used for combining the ...
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0answers
62 views

How to make the following data separable for the classification into three classes?

The figure below shows the PCA projections of inputs which are 14 meteorological features, (i.e. wind, temperature, humidity, pressure, and so on.) I would like to use any technique to make it more ...
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1answer
1k views

Why am I not seeing faster neural network training after upgrading to a vastly better GPU?

I was previously running my neural networks using the Lasagne library to build and train neural networks in Theano on an NVIDIA GTX 750 Ti. I'm using a genetic algorithm to tune the hyperparameters of ...
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1answer
27 views

What is the Best and easiest way to create a Classifer for Sentiment Analysis

Sentiment analysis using Machine Learning is a hot topic. Which is the best classifier to use based on the amount of training data available?
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75 views

Calculus of Variations with unknown cost function but some data

I have a problem that I've framed out in a particular way, but I don't know if I'm re-inventing the wheel here. Is there an existing literature base in this problem? Does it have a corresponding term ...
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1answer
634 views

Open source tool comparable to MATLAB Neural Network Tool Box?

Background I am a graduate student and a researcher. I do not like to rely on commercial products due to cost and also because I feel more comfortable in using and extending existing tools based on ...
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2answers
2k views

Markov (Chain) image generators?

Markov Chains can be used to generate, or auto-complete, text. https://en.wikipedia.org/wiki/Markov_chain#Markov_text_generators Training text is read, and some information about the text is ...
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30 views

How to find active region in treepartition Matlab object

I am trying to identify a non-linear plant using the identification toolbox of Matlab. In particular I would like to identify a non-linear arx model, where the nonlinearities are expressed by means ...
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1answer
101 views

Using kalman filter when samples don't have time index

Assume $X$ and $N$ are two sets of observations from two different normal distribution, where $X$ represents clean data and $N$ represents noise; and $A$ a projection matrix of a filter and the ...
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2answers
214 views

Learning parameters of noise and filter coefficients from data where data and noise both have Gaussian distributions

Assume $X$ and $N$ are two sets of vectors (observations) from two different normal distributions, where $X$ represents clean data and $N$ represents noise; and $A$ a projection matrix of a filter. ...
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0answers
150 views

scipy.linalg.sparse.eigsh does not work for generalised eigenvalues

I asked this question over at StackOverflow and someone told me that I'd get a better answer here. So here's my problem: I'm working on a machine learning project which involves doing a Principal ...
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2answers
2k views

Are there tasks in machine learning which require double precision floating points?

Double-precision calculations are significantly slower or more expensive than single-precision calculations. For example, the NVidia Tesla which performs well on doubles is much more expensive then ...
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1answer
131 views

How to train a model to classify object trajectories?

I have a tracker that outputs the trajectory $(x,y,z)$ of an object (e.g., a can). I want to use these trajectories to train a classifier (i.e., SVM) in order to infer the activity that the person ...
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1answer
118 views

Correct Weights Neural Network

I'm trying to make a neural network using MATLAB. But I'm finding that many problems do not get solved. These are the formulas on which I based: $$ Layers\ in\ Neural\ Network = [0, ..., i, ..., out] ...
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2answers
7k views

Use of machine learning in computational fluid dynamics

Background: I have only built one working numeric solution to 2d Navier-Stokes, for a course. It was a solution for lid-driven cavity flow. The course, however, discussed a number of schemas for ...
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1answer
37 views

Interpolation of Data Value using Optimized Weighting of Its Features

Assume I have a data set $ { \left\{ {x}_{i} \right\} }_{i = 1}^{N} $ which represents the value of each data point. For each data we have its features $ {f}_{i} \in {\mathbb{R}}^{d} $. The model I ...
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1answer
66 views

Feedforward net lagged prediction

I am trying to predict y(t+1) of a function by using a feedforward neural network with Matlab. The inputs are the previous 3 previous values (y(t-2), y(t-1), y(t)) and the training output is the ...
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0answers
37 views

What library can you use to detect personalities from comments? [closed]

I have a bunch of comments from my website that I want to use to build a profile of someone's personality based on the topics they chose to write in and the their specific comments. I know that this ...
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2answers
164 views

Algorithms for searching in high-dimensional binary data spaces

Is there any algorithm that can learn/search efficiently the best sequence of 1's and 0's of length $n$ to fulfill certain performance? The search is performed in a high-dimensional binary data space. ...
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0answers
65 views

approximation of nonlinear time-dependent system with history

I have two time-dependent coupled equations. One of which is several orders of magnitude more computationally demanding than the other. I am trying to use machine learning to reproduce the behavior of ...
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5answers
2k views

Seeking a free symbolic regression software

Now that Formulize / Eureqa started charging $2500 a year for using it and having crippled the trial version, does anyone know of any replacements that can do similar things like find an equation ...
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1answer
373 views

Neural Network - single layer perceptron for multiple classes

For activation function in neural network, I have used the function $$\frac{1}{2}(\sin x +1) \enspace .$$ But this will give me the value of either 1 or 0, allowing me to classify only 2 classes. ...
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3answers
361 views

Algorithm: Extracting motion frequency from video

I was wondering if anyone knows of any algorithms or projects that can detect the frequency of a motion from a video clip. Like if I had a video of a bouncing ball with constant frequency, could an ...
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1answer
2k views

How to detect smiles using OpenCV and IntraFace?

I have installed OpenCV and IntraFace, now the code can detect landmarks on the face, like this : Now how can I convert this to a smile detector? I have the landmark points as an array, so I should ...
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2answers
75 views

Neural Networks: what's the point of learning features that don't linearly separate?

Unless I'm mistaken, deep neural networks are good for learning functions that are nonlinear in the input. In such cases, the input set is linearly inseparable, so the optimisation problem that ...
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1answer
67 views

SVM Math Question

I'm studying support vector machines and came across this paper. The following equation doesn't make sense to me, especially the part with the 0 ∀i. Any help understanding the basics of SVMs? yi * (...
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1answer
290 views

How could I implement this neural network in R? [closed]

In Establishing, versus maintaining, brain function: a neurocomputational model of cortical reorganisation after injury to the immature brain, Varier et al develop a neural network model of motor ...
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1answer
1k views

A Filter is Sum normalized to 0 and square normalized to 1

Firstly, About the Hierarchical Model And X (HMAX model), i still don't understand what is the difference between the "Original model" and "Standard model". Does in Standard, we use imfilter not conv2 ...
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1answer
157 views

Support Vector Machines as Neural Nets?

This is more of a conceptual question. I have learned about Neural Nets, and I have some clue as to how Support Vector Machines work. I read somewhere however that given the appropriate kernel (is ...