Questions tagged [machine-learning]

Questions about computer algorithms that automatically discover patterns in data and make good decisions based on them.

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3
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1answer
184 views

Using the appropriate machine learning algorithm [duplicate]

I am not sure if this is the right forum to ask this. I have some data of the houses, like their size(in square meters), if they use aircondition, how many residents live in, I have their electricity ...
10
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2answers
227 views

Which classifier is more accurate for a SVM classification?

I am learning the SVM classification and encounter a problem. I am not sure if this dilemma has a terminology for it. Assume we would like to classify patient by SVM given the samples of healthy ...
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2answers
4k views

What can be learned from the weights in a neural network?

I'm very new to neural networks, and have been trying to figure some things out. So, let's say you come across a neural network which has 100 inputs, a hidden layer with 200 nodes, and 32 outputs. ...
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1answer
79 views

What is the Meaning of the Notation [duplicate]

What is meant by saying an algorithm runs in time $Poly(|S|,n,\frac{1}{\epsilon})$. Can somebody explain with an example.
12
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4answers
6k views

Machine Learning vs System Identification?

Could anyone explain to me the differences & similarities between machine learning and system identifications? Are these just two names of the same thing? In this page, they say: Machine ...
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2answers
1k views

Data structure and algorithms for a medical diagnosis software

For an academic question, I plan to design a medical diagnosis system. Given a description of symptoms, produce a list of probable diseases (with closeness matching). I'm having some trouble finding ...
5
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1answer
314 views

What learning algorithm is appropriate for predicting one time-series from another?

I have eye-tracking data on two subjects -- a teacher, and a student. It's in the form (x, y, time), so there is a series of these for each subject. What the teacher looks at influences what the ...
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0answers
107 views

Help understanding an audio processing algorithm

I'm reading “Speech segmentation without speech recognition” by Dong Wang, Lie Lu and Hong-Jiang Zhang. The algorithm I'm looking at is a V/C/P (Vowel/Consonant/Pause) classification algorithm on a ...
1
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1answer
54 views

Pool of photos for term extraction

I need a pool of photos (if possible with description) for my project. I mainly have to perform term extraction for semantic searching. Is there something available out there that is made available ...
3
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3answers
325 views

Handwritten character recognition as characters are being traced

I'm looking for an OCR technique (PCA or SVM or anything else) in a peculiar setting. I want to detect the motion of the finger so that if someone writes something in front of the camera in the air, I ...
3
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2answers
497 views

Construct a context-free grammar for a given set of words

I have seen a few years back a nice and simple algorithm that, given a (finite) set of words in some alphabet, builds a context-free grammar for a language including these words and in some sense "...
3
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2answers
332 views

About the behaviour of multi-layer perceptrons

I have a multilayer perceptron. It has an input layer with two neurons, a hidden layer with an arbitrary number of neurons, and an output layer with two neurons. Given that ...
2
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1answer
120 views

Analyzing rules of articles in languages

I'm interested in finding a solution for the following problem: problem space: any language that has more than 1 article let's take German language as example. So the articles in German are "der", "...
4
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1answer
167 views

What Properties Matter For the Bound on Generalization Error of Hypothesis Set?

As I know, there are several upper bounds on the generalization error of hypothesis set with respect to sample complexity. For hypothesis space $V$, if the learning algorithm output the set of ...
5
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1answer
534 views

k-armed bandit - index policies vs. Q-learning

I am interested in the stateless k-armed bandit problem, where an agent repeatedly chooses one of k independent arms, each with a different distribution of rewards, and tries to maximize its total ...
3
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1answer
162 views

$\ell_1$ Minimization of Probability Distribution and KL-Divergence

Suppose through $\ell_1$ minimization I obtained two sparse probability distributions $P, Q$ which may contain many zero terms. Then I would like to compute the KL-Divergence of them $D(P || Q) = \...
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3answers
4k views

Do linearly dependent features in feature vectors improve the feature vector?

I was reading Wiki on feature vectors, and as far as I can see, it suggests creating new features from already existing features: Higher-level features can be obtained from already available ...
3
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1answer
3k views

Machine Learning: how to correctly calculate gradient descent for simple linear problem

So, I was trying to learn machine learning, and, after watching a couple of Andrew Ng's lectures decided to try and write a simple piece of code to determine what someone's salary would be based on ...
3
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1answer
133 views

Why use joint trees in Graphical Models?

I am wondering why some methods transform the underlying graphical model (Bayesian Network for example) to a junction tree¹? What are the advantages? Also what are the limitations? I believe it's ...
7
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2answers
227 views

Building probability distribution functions from observation

There are N players and M objects, each of the objects has a value. Each player has a strategy in choosing an object. Each round a player will choose an object, many players can choose the same object....
9
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1answer
208 views

Fixed-length decision-tree-like feature selection to minimize average search performance

I have a complex query $Q$ used to search a dataset $S$ to find $H_\text{exact} = \{s \in S \mid \text{where $Q(s)$ is True}\}$. Each query takes on average time $t$ so the overall time in the linear ...
2
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2answers
444 views

Unsupervised anomaly detection: assigning the clusters to normal and anomaly

Having a unsupervised algorithm done on a dataset (e.g. K-means), how can I determine which cluster is normal and which is anomalous (for 30 clusters, for example)? If the dataset contains normal ...
10
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0answers
1k views

Alternatives to SVD for rank factorization

I have rank-deficient matrix $M \in \mathbb{R}^{n\times m}$ with $\text{rank}(M) = k$ and I want to find a rank factorization $M = PQ$ with $P \in \mathbb{R}^{n \times k}$ and $Q \in \mathbb{R}^{k \...
5
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2answers
487 views

Algorithm to find the probability of a given text to be about a large topic

I want the conditional probability for each topic (being the word that we give as input). For example, the text being have seen and reviewed your requirements you posted here. If you can give me ...
2
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1answer
4k views

Using Funk SVD with SGD?

I work on a recommender system framework which is implemented with a variant on Funk SVD (See his explanation of his algorithm here). However the framework that we are trying to integrate doesn't ...
6
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5answers
580 views

Machine Learning - Support Vector Machines

I'm looking for good resources regarding Support Vector Machines, or suggestions where to start learning SVM. Already used references: Stanford ML course by Andrew Ng is great place to star A ...
2
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1answer
1k views

What are the mathematical prerequisites for adaptive machine learning algorithms?

I am a PhD student in Computer Science who switched his PhD a little bit towards ML algorithms combined with something else... I am an expert in that something else, say image processing, but not an ...
5
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3answers
206 views

How can lazy learning systems simultaneously solve multiple problems?

On the english Wikipedia it says about lazy learning systems: Because the target function is approximated locally for each query to the system, lazy learning systems can simultaneously solve ...
3
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2answers
344 views

What could you learn from studying player movement and behaviour on online FPS games?

Just thinking of Counter Strike as a canonical example, if you have a coordinate representation of the map and for every player you have a complete history of everything you might need for every ...
3
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1answer
149 views

Which Is a Better Way of Obtaining Scales, Gaussian Blur or Down Sampling?

In computer vision, scales are important when we carry out a scene analysis. Choosing different scales affect the result of the analysis. For example, if a face is relatively small in the scene, then ...
5
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1answer
319 views

Why does the experience propagation rule for checkers work in Tom Mitchell's book?

In Tom Mitchell's book "Machine Learning", Chap.1, a checkers game is used to illustrate how machine learning can be applied solve problems. An experience propagation rule is described for iterative ...
3
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2answers
161 views

Analyzing Twitter Relationships

I'm not even sure if this is the right StackExchange to post this, but it seems like sentiment analysis would go here. What would be the best approach to determine if two people on Twitter are ...
13
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1answer
15k views

Smoothing in Naive Bayes model

A Naive Bayes predictor makes its predictions using this formula: $$P(Y=y|X=x) = \alpha P(Y=y)\prod_i P(X_i=x_i|Y=y)$$ where $\alpha$ is a normalizing factor. This requires estimating the parameters ...
29
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4answers
69k views

What exactly is the difference between supervised and unsupervised learning?

I am trying to understand clustering methods. What I I think I understood: In supervised learning, the categories/labels data is assigned to are known before computation. So, the labels, classes or ...
3
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2answers
153 views

Finding Feature Representation Such That Two Samples Are Similar in Feature Space

Consider one specific useful function of our human brain: abstraction of object. Take the example of two pictures: if we are told the pictures are similar, we actually make conclusion about the ...
4
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1answer
354 views

Is there a search engine over Artificial Intelligence and Machine Learning -related sites?

Sometimes it is necessary to dig into Artificial Intelligence or specifically Machine Learning problems to make a research. Common googling (in my own experience) usually doesn't help much due to a ...
3
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1answer
171 views

Improve Markov Chain results

Apologies for another Markov Chain question but this one is best given its own question to avoid confusion. I am using a Markov Chain to get the 10 best search results from the union of 3 different ...
16
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2answers
10k views

Must Neural Networks always converge?

Introduction Step One I wrote a standard backpropegating neural network, and to test it, I decided to have it map XOR. It is a 2-2-1 network (with tanh activation function) ...
9
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1answer
634 views

Machine Learning algorithms based on “structural risk minimization”?

Which machine learning algorithms (besides SVM's) use the principle of structural risk minimization?
8
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1answer
499 views

Vapnik-Chervonenkis Dimension: why cannot four points on a line be shattered by rectangles?

So I'm reading "Introduction to Machine Learning" 2nd edition, by Bishop, et. all. On page 27 they discuss the Vapnik-Chervonenkis Dimension which is, "The maximum number of points that can be ...
2
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1answer
3k views

Nilsson's sequence score for 8-puzzle problem in A* algorithm

I am learning the A* search algorithm on an 8-puzzle problem. I don't have questions about A*, but I have some for the heuristic score - Nilsson's sequence score. Justin Heyes-Jones web pages - A* ...
10
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2answers
351 views

How do I classify my emulator input optimization problem, and with which algorithm should I approach it?

Due to the nature of the question, I have to include lots of background information (because my question is: how do I narrow this down?) That said, it can be summarized (to the best of my knowledge) ...
19
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3answers
7k views

Line separates two sets of points

If there is a way to identify if two sets of points can be separated by a line? We have two sets of points $A$ and $B$ if there is a line that separates $A$ and $B$ such that all points of $A$ and ...
19
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1answer
879 views

Efficiently computing or approximating the VC-dimension of a neural network

My goal is to solve the following problem, which I have described by its input and output: Input: A directed acyclic graph $G$ with $m$ nodes, $n$ sources, and $1$ sink ($m > n \geq 1$). Output: ...
6
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1answer
162 views

How to represent the interests of a Facebook user

I'm trying to figure out a way I could represent a Facebook user as a vector. I decided to go with stacking the different attributes/parameters of the user into one big vector (i.e. age is a vector of ...
15
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4answers
4k views

How to devise an algorithm that suggests feasible cooking recipes?

I once had a veteran in my course that created an algorithm that would suggest cooking recipes. At first, all sort of crazy recipes would come out. Then, she would train the cooking algorithm with ...
14
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2answers
8k views

Machine learning algorithm to play Connect Four

I'm currently reading about machine learning and wondered how to apply it to playing Connect Four. My current attempt is a simple multiclass classificator using a sigmoid function model and the one-...
11
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2answers
206 views

Non-Parametric Methods Like K-Nearest-Neighbours in High Dimensional Feature Space

The main idea of k-Nearest-Neighbour takes into account the $k$ nearest points and decides the classification of the data by majority vote. If so, then it should not have problems in higher ...
2
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1answer
200 views

Pattern classification: what goes into the sample?

I am trying to compare the performance of a classification result with Bayes classifier, K-NN, Piece wise component analysis (PCA). I have doubts regarding the following (please excuse my lack of ...
7
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2answers
205 views

Issue in comparing classifiers for pattern recognition

I have designed a classifier M which recognizes gestures and classifies it under any category always. A gesture is classified based on the hamming distance between the sample time series y and the ...