Questions tagged [machine-learning]

How can we build computer systems that automatically improve with experience, and what are the fundamental laws that govern all learning processes?

From The Discipline of Machine Learning by Tom Mitchell:

The field of Machine Learning seeks to answer the question "How can we build computer systems that automatically improve with experience, and what are the fundamental laws that govern all learning processes?" This question covers a broad range of learning tasks, such as how to design autonomous mobile robots that learn to navigate from their own experience, how to data mine historical medical records to learn which future patients will respond best to which treatments, and how to build search engines that automatically customize to their user's interests. To be more precise, we say that a machine learns with respect to a particular task T, performance metric P, and type of experience E, if the system reliably improves its performance P at task T, following experience E. Depending on how we specify T, P, and E, the learning task might also be called by names such as data mining, autonomous discovery, database updating, programming by example, etc.

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Supported Vector Machine constraint condition.

I think I can follow the following statement, but I can't reach the conclusion "subject to $\sum_{i=1}^n c_i y_0 = 0$". Could someone give me a pointer from which to reach this constraint? Thank you! Consider a constrained optimisation problem: For…
WishingFish
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SVM algorithm for machine learning. Algebra in which it was constructed and description?

As I understood this is a simple full description of SVM algorithm: There are set of elements (mathematically points). These elements describe as ordered pairs of Cartesian product of two sets X and Y. The approach is to draw a line in the "plane"…
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Machine learning: overfitting phenomena

Please explain why we should avoid "overfitting phenomena" in training a learning model and how to detect it?
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System of equations for non linear functions

Im readign a book about Deep learning and in this book the author states something like the following when explaining why we need an error function. A neural net can bee seen as a system of equations. We have a bunch of unknowns (the weights) and a…
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Defining Classes for Maximum Likelihood Classifier

I am doing a course in Machine Learning, and I am having some trouble getting an intuitive understanding of maximum likelihood classifiers. What I am trying to do is to perform Principal Component Analysis on the Iris Flower Data Set, and then…
casper
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Scaling and cross-validation in statistical models

Let's say i have a two dimensional dataset (X and Y variables). My goal is to fit a model that best describes the X-Y relationship Using a training subset of the dataset and then evaluate the performance using another test subset. and let's say i…
rodrigo
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GMM EM-algorithm VS the Multinomial Logit/Probit Model of Discrete Choice Modeling

I am taking two courses where I learn GMM and MNL separately. However, I do see some similarities between they two: like we need indicator variable for discrete choice modeling when using the MLE, while we also need the categorical variable for…
DQ_happy
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What does it mean for a probability model to be parametric?

Our course slides offer the following definition: "A parametric probabilistic model is a set of probability distributions indexed by a finite-dimensional parameter vector." This description defines "parametric probabilistic model" in terms of…
Dan Barowy
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reinforcement learning as an observer

My task is to build a system that can make predictions about a player's future in-game actions by observing his/her history of interaction with the environment. Reinforcement learning is about observing the state, s, acting (which takes you to…
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Least mean squares (machine learning algorithm)

This is the rule: \begin{align*} \theta_j:=\theta_j+\alpha\sum_{i=1}^{m}(y^{(i)}-h_\theta(x^{(i)}))x_j^{(i)} \space (\forall j) \end{align*} I can't get the correct thetas, they quickly get to infinity or some very large numbers. My question is, for…
Andrew
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Question on understanding Dirichlet process

I have questions on understanding this article about Dirichlet process. If you look at the beginning of section 2.1, it shows three equations 2.1, 2.2, 2.3. The question is I don't understand what exactly those probabilities represents and why we…
eChung00
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4 points not separable by SVM

We know in a support vector machine: Considering we have a linear feature mapping $\phi(x_n)=x_n$ and the XOR problem. We have 2 classes in $R^2$, class 1 $ t_+=+1$ and class 2 $t_-=-1$ and 4 points where $x_1, x_2$ are from class1 and $x_3, x_4$…
user136542
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Why do polynomial sequences have the coefficient $\sqrt2$ in front of them as in $\phi(x) = [x_1, x_2, \sqrt2x_1x_2, x_1^2, x_2^2]$

Why do polynomial sequences have the coefficient $\sqrt2$ in front of them as in $\phi(x) = [x_1, x_2, x_1x_2, x_1^2, x_2^2]$? For example if our original feature space is: $$x = [x_1, x_2]$$ Then why do we have $\sqrt2$ in the following polynomial…
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Why is the constraint for SVM with offset the way it is? $\sum^{n}_{t=1}\alpha_ty^{(t)} = 0$

When doing the dual formulation of the SVM we get the lagrangian: $$L(\theta, \alpha) = \frac{1}{2}||\theta||^2 + \sum_{t=1}^n{ \alpha_t(1-y^{(t)}(\theta \cdot x^{(t)} + \theta_0) )}$$ and then by lagrange multipliers we get that one of the…
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SVM primal formulation, does the constants constraints matter/

When finding the maximum margin separator in the primal form we have the quadratic program: $$min\frac{1}{2}||\theta||^2$$ $$\text{ subject to: } y^{(t)}(\theta \cdot x^{(t)} + \theta_0) \geq 1, \ t=1,...,n$$ Saying basically to find the maximum…