Methods and principles of building "computer systems that automatically improve with experience."

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Questions about understanding convolutional neural network (with Tensorflow's example)

I've recently seen tutorials from google's tensor flow. It was about convolutional network and way of convolution way slightly different from what I first learned. ...
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8 views

Neural Network border condition or extrapolation data

I was reading the user guide of NN for Matlab and I found this quote about extrapolation data: It is important that the data cover the range of inputs for which the network will be used. ...
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36 views

Use AUC for model comparison but what is the optimal threshold for final prediction

We can compare the performance of different models using AUC ROC and pick the one with large AUC. Then, we still need to choose and use specific threshold to predict the label for the test data. I ...
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33 views

Independent and conditionally independent

I was wondering if two variables can be independent and conditionally independent. For example, A and D are independent. But are they also independent given the evidence C? I think they are, because ...
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92 views

In TensorFlow's Computational Model, is it possible to implement general machine learning algorithms?

https://www.tensorflow.org/ All the projects on TensorFlow I have seen in GitHub implement some kind of Neural Network model. Given TensorFlow is an improvement over the DAG (it's not acyclic any ...
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32 views

What systems are based on the following paper? [closed]

http://papers.nips.cc/paper/3150-map-reduce-for-machine-learning-on-multicore.pdf This paper has Andrew Ng as one of the authors. I really liked the idea presented in this paper, and when I looked ...
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16 views

Using cross validation to decrease variation in prediction outcomes

Im trying to predict the won category of some soccer matches. I have the following df: ...
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14 views

Evaluating a clustering against multilabels

I have a clustering of text documents, where each document is uniquely assigned to a cluster. I have a set of labels (keywords) attached to each document. That is, each label may be applied to many ...
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28 views

Is it a good idea to use $\eta = \arg \max( L(y, f(x) )$ to choose the step size for stochastic gradient descent (SGD)?

I wanted to have a good (as optimal as possible) automatic way of choosing the step size for minimizing the generalization error $\mathbb{E}_{ (x,y) \sim p_{x,y} }[L(y, f(x))]$, where $L$ is the loss ...
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30 views

Find sample complexity given dataset (hypothesis space)

In preparation for upcoming exams I'm trying to solve some exam questions from previous years. However, I got stuck on this following one: Assume given a dataset with n predictive attributes $x_1 ...
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72 views

When to use RBF networks instead of multilayer percetron?

I understand that a radial basis function neural network (RBF) usually has 1 hidden layer, and it differs from a multi-layer perceptron (MLP) via its activation and combination functions among other ...
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60 views

Find covariance if given mean and variance

I have a signal x that I want to classify in one of the classes A and B in which the means are Ma=[0.5,0.6] and Mb=[2,2] and with variances ...
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1answer
42 views

Text Classification for (Short) Open-Ended Survey Responses?

I am new to text mining/classification, and really want to learn more from this community. My data are open-ended survey responses (n=about 6,000) in which the respondent described what happened at ...
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8 views

Score based training libraries

Suppose I have a machine learning problem. However, the evaluation of the function that we are trying to predict is quadratic weighted kappa and it cannot be evaluated on one single data point. It is ...
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2answers
49 views

How to create a variable that is present in test data set but not in train?

Im try to do a classification but i have a variable production budget which is present in test dataset and not in train. so how do i proceed. could i impute that variable somehow. i dont want to drop ...
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19 views

Probability distribution in RandomForest

I'm trying to build a model with RandomForest in R, but I'm facing some issues. I'am using: ...
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1answer
40 views

Dealing with noisy features in a classification problem

I'm working on a classification problem whose features are very noisy. I have a table with the 'official' feature levels, but the actual data loosely resemble them. For example, to represent a value ...
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14 views

want to evaluate the performance of my model

I have developed a machine learning model to predict outcome of cricket matches and the accuracy I am getting from my model on the test set is 65% and on the training set is 66%. I want to know if it ...
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19 views

Is fitting hyperparameters to data in a Machine Learning model appropriate?

I have constructed a machine learning model (it is similar to Naive Bayes) within the Bayesian framework, and as such, have must select priors. In my brief exposure to Bayesian statistics, I was ...
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35 views

How to detect outliers?

I have a matrix where the rows are the data points (samples) and the columns are the features (predictors). Let's say I have 1000 data points and 20 features, i.e. the matrix is of size 1000 x 20. ...
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28 views

How to combine perceptron weights and probabilities

I am working on machine transliteration using structured perceptron to learn the model parameters at word level. I am using beam-search to extract the top $n$ transliterations of a word and would like ...
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1answer
37 views

Kernel nonparametric regression

One of the methods for nonparametric regression is using kernels. My question is what are the conditions on the kernels functions in this method? In other words how can I decide if a given function ...
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1answer
35 views

Linear Regret for epsilon-greedy algorithm in Multi-Armed Bandit problem

I am reading about $\epsilon$-greedy algorithm in Multi-Armed Bandit (or $K$ armed bandit) problem, as can be seen here: https://en.wikipedia.org/wiki/Multi-armed_bandit#Semi-uniform_strategies. For ...
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31 views

Difference in execution times between caret and randomForest (even with method = “none”)

I have a dataset with 1205 observations and 285 predictors (all but one categorical). It is a binary classification task. When I run randomForest, it executes in less than 1 second. When I run ...
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47 views

Curve Fit with logarithmic Regression in Python

I need to find a model which best fits my data. It's look like this: So I thought about logarithmic regression. But when I try to make a simple fit in python I get the following result: My code ...
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1answer
20 views

On skewed distributions, should the test/train/cross validation set be similar to the real set

On a skewed distribution (say there are two classes and the distribution is 2%-98%), given the small number of examples of one of the classes, would it be correct to have them distributed 50%-50% for ...
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35 views

Matching algorithm using probabilities and counts

I have a data set of id’s with location and time information. I want to determine which location is the home address of the id. For example, Id 1 could have the following data where percentage ...
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29 views

How to understand the result of label propagation algorithm

The graph is an undirected graph, “Protein 4","Protein 5", "Protein 6",... represents the vertex of graph. The value of two vertices with connected is 1 and that without connected is 0 in the ...
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1answer
54 views

Is that correct about dimensionality reduction and clustering?

Could you please help me to understand it because I'm not sure if I got it correctly. Let's say I have a dataset, of persons, with 100 features, various characteristics like height, weight, age, etc. ...
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14 views

Inference in Bayesian network Using bnlearn package

In this link Prediction of continuous variable using "bnlearn" package in R , the author talk about how I can find the conditionl probability of P(node(C)\ the rest node)=P(C\A,B,D,E,F,G) ...
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23 views

What is the “expressive power” of the composition function in a Recursive Neural Tensor Network?

I wasn't entire sure if this question belongs here or on math.stackexchange, since it's only partially about machine learning, but perhaps more of a conceptual question about linear algebra (or ...
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19 views

Continuous HMM library/Tool for continuous gesture recognition

There are many HMM tools, but most of them only support discrete density HMM (like Matlab). even the tools that support continuous density HMM can only be used for discontinuous gesture recognition. ...
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1answer
32 views

How the Markov Chain Monte Carlo ensure the stationary distribution converge to the target distribution?

I am reading about the MCMC but now I got a lot of questions. Firstly, It says we could construct a markov chain which satisfy the detailed balance:...
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160 views

XG Boost vs Random Forest for Time Series Regression Forecasting

I am using R's implementation of XGboost and Random forest to generate 1-day ahead forecasts for revenue. I have about 200 rows and 50 predictors. (As I go further in time I have more data so more ...
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51 views

Accuracy of training sample in Random Forest model in R

I'm using a Random Forest algorithm in order to construct a classification model, and I HAVE to check the accuracy of my rf model in the training sample, but as you can see in this answers : ...
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2answers
56 views

What algorithm should I try to predict number of tweets

Background I have been collecting data of each tweet being sent out for each article. The data is like this. created_at, user_id, article_id xxx, x, x y, y, y ...
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1answer
46 views

How to train a neural network on large images?

I am working through ideas for a computer vision problem, and most of the examples I see online use extremely small images, often 32x32 pixels. Does it make sense to try to train a neural network on ...
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1answer
39 views

How to combine two accuracy results?

If I am doing a machine learning experiment A and my accuracy lies in the interval of 0.8 +/-0.03 and I have a machine learning experiment B with an accuracy in the interval of 0.9 +/-0.1, how can I ...
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46 views

How to predict with the known information in an undirected graph

Protein-protein interaction networks are known. It is an undirected graph. Each row of the networks is like this (Protein 2 - Protein 6), and It represents the interaction between Protein 2 and ...
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1answer
34 views

Is validation set important in SVM regression analysis

I am new to machine learning and currently reading a paper about a ANN modelling in which they have divided their dataset into Training , validation and testing set. I have carried out some minor SVM ...
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12 views

Derivation of bias-variance decomposition expression for K-nearest neighbor regression

In the Elements of statistical learning it is written that the bias-variance decomposition takes the simple form in case of K-nearest neighbor regression fit $$ Err(x_o)= ...
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1answer
47 views

Calculating Neural Network Error

I am confused with these two error formulas for artificial neural networks: \begin{align} \text{Error} &= {\rm target} - {\rm output} \\[7pt] \text{Mean Square Error} &= ...
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1answer
35 views

Oscillating validation accuracy for a convolutional neural network?

My CNN training gives me weird validation accuracy result. When it comes to 2.5,3.5,4.5 epochs, the validation accuracy is higher (meaning only need to go over half of the batches and I can reach ...
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19 views

Loopy belief propagation on non-factor graph

I implemented loopy belief algorithm on a graph that is not a factor graph, but I cannot figure out how to normalize the messages so that I do not end up with underflow. What is the correct way to ...
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1answer
49 views

two ways of predicting a categorical variable?

I'm working on a machine learning problem where I have to predict a categorical variable that has 12 different values, lets say A, B, C and so on.. (one thing I should mention is that one of the ...
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34 views

Comparing learning methods for facial recognition

I'm studying machine learning for a final exam and I'm trying to solve an example exam question where you need general knowledge of various machine learning methods. The question goes as follows: ...
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1answer
28 views

Producing samples from exponential family when sufficient statistics are known

Suppose I have a distribution which belongs to an exponential family, of the form $$p(x) = \frac{\exp(-\sum_k \eta_k T_k(x))}{Z},$$ where $T_k(x)$ are a fixed set of sufficient statistics, $\eta_k$ ...
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69 views

Deep Learning for Regression

I have dataset of 15 features and the goal is to estimate a best fitting curve (regression). Now I want to use a deep learning technique for this purpose. Now I see that there are many architectures ...
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55 views

Important questions regarding the methodology for constructing classifiers with R package caret and tree based algorithms

I'm currently playing with caret R package, with one merged microarray affymetrix dataset(paired tissue samples), in order to build and test various classifiers, mostly based on trees-such as random ...
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Is it a good practice to always scale/normalize data for machine learning?

My understanding is that when some features have different ranges in their values (for example, imagine one feature being the age of a person and another one being their salary in USD) will affect ...