Tagged Questions

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

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0answers
11 views

How does SARSA handle episode termination

When applied to domains that are episodic and have a "final" state but no final action, like a game, how does SARSA update the Q-values? e.g. A game agent would receive this series: ...
3
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2answers
43 views

Why is the O(nW) algorithm for the Knapsack problem not a polynomial one?

On the wikipedia page for the knapsack problem it says that the runtime is $\mathcal{O} (nW)$ and goes on to say that this doesn't violate its classification as NP because the input size is related to ...
0
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0answers
20 views

Merging two disconnected graphs

Firstly, I'd like to apologize for any misused terms or ways I could have made the description much more succinct. It's been a while since I took machine learning during my bachelor's. I have two ...
0
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0answers
16 views

How can an EE doing a project with large sets of data implement machine learning techniques?

I have a general overview of what machine learning is, but I have no idea how to implement algorithms etc. For ex: If I have a system where I have a sensor system to detect each food item a person ...
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0answers
9 views

How to make logical inference from simulated data

I have data collected from a computer simulation of football games which seem to have recurring patterns of the following form. if madrid plays arsernal and the match ends under 3 goal, then on ...
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0answers
19 views

k means for 2d data [on hold]

I am implementing k-means for 2d data and stuck at the part where we assign centroids and later each instance to the cluster. I wanted to know the next strategy that I should go ahead with ie. how do ...
2
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1answer
14 views

What's the difference between Adaptive Control and Hierarchical Reinforcement Learning?

After watching Travis DeWolf presentation on scaling neural computation, I'm a bit confused about the difference between Reinforcement Learning (whether hierarchical or not) and Adaptive Control. They ...
3
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0answers
16 views

What's the difference between adaptive control and a kalman filter?

From my basic understanding of Adaptive Control, I understand that it uses the error and the velocity of the error to approximate the error in the solution space of a problem, thus allowing for ...
2
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0answers
18 views

Training a model to match two time series

Context I have two related time series, I want to learn to produce one from the other. However, they aren't synchronous, and the lag between the two does not revert to the mean, it accumulates. ...
1
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1answer
28 views

I am having trouble understanding (and implementing) logistic regression for classifying into three classes

(For reference, i am using Kevin P Murphy's Book "Machine Learning: A Probabilistic Perspective" and implementing with MATLAN - without any toolboxes) I have a dataset with 392 samples (rows), each ...
1
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0answers
13 views

backpropagation algorithm seems to be forcing output values to middle than extremes

I have been playing around with artificial neural networks lately, specifically with the prospect of trying to replace the contrastive divergence algorithm with some type of evolutionary metaheuristic ...
3
votes
1answer
45 views

How does the momentum term for backpropagation algorithm work?

When updating the weights of a neural network using the backpropagation algorithm with a momentum term, should the learning rate be applied to the momentum term as well? Most of the information I ...
0
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0answers
13 views

Is this an accepted/valid clustering evaluation metric?

We have a clustering algorithm where the number of clusters isn't known to the algorithm - it iteratively creates clusters out of similar-looking data points. The evaluation metric we're currently ...
4
votes
1answer
47 views

How exactly do you calculate the hidden layer gradients in the backpropagation algorithm?

I have been going through the description of the backpropagation algorithm found here. and I am having a bit of trouble getting my head around some of the linear algebra. Say I have a final output ...
1
vote
1answer
22 views

are the activations of hidden nodes in an ANN binary or real valued?

this may seem to be a pretty basic question, but it is something i have been puzzling over for some time. when calculating the activations of nodes in a hidden layer in an ANN using sigmoid neurons ...
0
votes
1answer
50 views

Which type of randomized algorithm is best suited for web crawling?

I have decided to implement a web crawler for my CS major project. The project is focused towards adaptive search. I want the pages to be as user specific as possible and time efficiency is not much a ...
1
vote
1answer
33 views

In ID3 algorithm, which attribute to choose if information gains are equal?

In the ID3 algorithm for building a decision tree, you pick which attribute to branch off on by calculating the information gain. What happens if the calculated information gain is equal for two ...
2
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0answers
24 views

Reinforcement learning - state space and action space

I am working on a reinforcement learning strategy for parameter control of a local search heuristic. The complete state for this RL problem can be defined as $S = \{s, p\}$, where $s$ and $p$ ...
2
votes
2answers
42 views

Combining multiple HMM models

Is there any way to combine multiple Hidden Markov Models trained from different sets of data? For example, I want to detect the phases of a sequential activity. I collect two sets of data by using ...
0
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1answer
50 views

Find pixel mapping matrix with minimum iterations

The Situation I am an electronics engineer and on a volunteer team that have built a prototype eye that has 200*200 sensors that are mapped to the optic nerve, the connection to the optic nerve is ...
3
votes
2answers
48 views

How do I measure the reliability of a confidence value in a predictive algorithm?

Supposing I have some algorithm that is able to provide me with a confidence value for some event occurring. Let's say on day 1 it tells me that there is a 80% chance it will rain, on day 2 it tells ...
0
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0answers
24 views

How to discern devices based on their traces?

I would greatly appreciate your advice on following machine learning problem: I need to train a classifier to learn a device's behavior. The device itself can be observed under different ...
0
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0answers
19 views

What math is required for machine learning, neural networks etc.? [duplicate]

I'm planning to start learning more in depth about neural networks and machine learning. Can someone tell me which math will I need the most, and also recommend me good books or internet lessons in ...
6
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2answers
97 views

Are there ways to automatically (no human testing) measure a $9 \times 9$ Sudoku puzzle's average hardness for a human to solve?

So most resources providing Sudoku puzzles assign a difficulty category to each puzzle, even some I've seen with 15 or more difficulty categories. But what is a good way to assign these difficulty ...
1
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0answers
49 views

Improving MSE as fitness function for a genetic algorithm

I am implementing an autoencoder neural network in matlab, the weights of which are being optimised by a genetic algorithm. At the moment I am working on the first layer, trying to get an improved ...
1
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0answers
29 views

Disadvantages to using simple step functions for activation in neural networks?

From what I have read, the main advantage to using tanh(x) or sigmoid(x) as an activation function for neural networks is that it is very easily differentiable. I am trying to implement a neural ...
0
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1answer
56 views

How to reconstruct the image from a neural network output?

I am trying to use the genetic algorithm to optimise a multi-layered neural network for image classification (i am using a subset of the MNIST handwritten digit data set as my initial dataset, but ...
1
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0answers
27 views

Detect bad acceleration deceleration of car [closed]

I am working on aggressive driving behavior android application. This will be implemented via supervised learning, wrong actions will be recognized and added while driving the car. To check ...
0
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0answers
40 views

Sample Complexity for Real-Valued PAC-Learnable Functions

Can anyone shed some light on how the VC Dimension affects the sample complexity bounds of infinite hypothesis classes with real-valued outputs in PAC learning, or how to calculate the sample ...
3
votes
1answer
56 views

How can we combine badly trained decision trees to a good one?

I was reading about decision trees and this is what I understood: We build decision trees by choosing an attribute and building subtrees (which are also decision trees) as children of the node ...
2
votes
5answers
179 views

Machine Learning and Neural Networks for High School Students

I hope this question is appropriate for this forum. In this summer I am giving a 3-day workshop on machine learning and neural networks for advanced and very enthusiastic high school students which ...
0
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0answers
49 views

Activity prediction in a kitchen

Here is the scenario: There are three chefs(A- main chef, B and C- assistant) working together to prepare a diner set. The sequence of the event is as following. Start: The three chefs enter the ...
0
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0answers
14 views

What are Pairwise intensity comparison in binary image descriptors?

Recently many binary descriptors have come u like BRIEF, ORB etc. A common ste in such descriptors is to chose a sampling pattern and perform pairwise intensity comparisons for constructing the binary ...
2
votes
3answers
135 views

Does programming language detection need more input than natural language detection?

I wonder which one of the two needs a larger input to achieve a decent accuracy: programming language detection or natural language detection? More details: Definition of Language detection: ...
2
votes
1answer
37 views

Closed form solution for a single layer linear perceptron

Let f be a one-layer neural network which is linear (ie. no activation function). Let it have $p$ inputs and $q$ outputs. These are fully connected by weights $W$. We have $n$ inputs $x \in ...
1
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0answers
17 views

Baseline approaches for likes prediction

I have a small user-item matrix (25k x 1.8k) describing how users liked or disliked some of the items. Users don't have any attributes but items have several features. I would like to be able to ...
2
votes
1answer
42 views

Generative Machine Learning algorithms on tree structure

I'm looking into PCFG sentence grammar dependency structure parsing using StanfordNLP PCFG parser. It generates tree structures represented as a string like this: ...
0
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0answers
46 views

Where to start studying about HTM?

I am looking for references (pedagogic and beginner friendly!) to these two topics, hierarchical temporal memory algorithms applied to deep planning problems (multi-layer) neural networks trained ...
1
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0answers
46 views

Two classes of documents. Find weighted relations between them

I have an NLP problem and a potential solution, but I’m a bit green here, so I’m looking for some validation or alternative suggestions. Background I have two types of documents: one is a set of ...
2
votes
1answer
35 views

Why does ε-greedy $Q$-learning not oscillate?

I have a intuitive question on the convergence of $Q$- learning. In $Q$ learning for each step a $Q$- value is learned for the state-action pair where the action is selected according to the ...
3
votes
1answer
74 views

Extracting features for texture classification

I m a beginner in the field of pattern recognition and computer vision. I m working on a project right now to classify t-shirt patterns into three categories i.e. solids, stripes and checks. I have ...
1
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0answers
29 views

What is the difference between “objective function”, “error function”, “criterion function” and “cost function” in the context of neural networks?

The title says it all: I have seen three functions so far, that seem to be the same / similar: error function criterion function cost function objective function I am currently working on ...
1
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1answer
62 views

How to implement the regret matching algorithm?

My question is the following: How to calculate the regret in practice? I am trying to implement the regret matching algorithm but I do not understand how to do it. First, I have $n$ players with ...
3
votes
1answer
31 views

Training given pairs of similar values, not labels

I have pairs of "similar" values $(x_i, y_i)$ drawn from a space $x_i, y_i \in S$, and want to train a neural network $N$ such that $N(x_i)$ would be "close" to $N(y_i)$ for all $i$, yet, to make it ...
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votes
1answer
17 views

Training Error & Convergence to True Error

I Take some online class for Machine Learning. one of teacher say this sentence. if we have m data points, the training error converges to the true error as m → ∞. i thought, this sentence not ...
0
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1answer
34 views

VC Dimension Calculation for Intervals

As i See in ML Course a VC dimension calculation is very theoretical. What is the VC-dimension of intervals in R? The target function is specifieed by an interval, and labels any example positive ...
1
vote
3answers
159 views

Over-fitting Always Occurs?

i get stuck in one sentence in machine learning. i read tom Mitchel book on ML, and some other materials. if we have small training set, always over-fit can occurs? or is likely to occurs? i read ...
-1
votes
1answer
40 views

Policy function π in Reinforcement learning unclear

I have one question about policy function in Reinforcement learning. in fact this function indicates which action should be done in each state? Or this function indicate for get the ...
-2
votes
1answer
48 views

Neural Network Design Challenge

i'm studying for PHD Entrance Exam on Stanford. one of previous material exam designed very challenging. i want to design a NN for classifying following 2-class problem. 1) output should be -1 or ...
1
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0answers
17 views

basic doubt on policy iteration

consider the policy iteration algorithm for a finite state MDP. Suppose the initial policy is a stochastic policy. Now, can the optimal policy be deterministic after improvements ? Or, can we say that ...