mit machine learning course online

is more than one, the Newton method iterates over the rule:Newton's method usually has a faster convergence rate than the batch gradient, and it takes a much smaller number of iterations to get close to the minimum value. However, when the parameters of the model are many (n), the computational cost of the Hessian matrix will be large, resulting in a slower convergence rate, but when the number of arguments is not long, the Newton method is usually much faster than the gradient descent.Summariz

Model (how to simulate)---strategy (risk function)-algorithm (optimization method)First section:Basic concepts and classifications of machine learningSection II:Linear regression, least squaresBatch gradient descent (BGD) and random gradient descent (SGD)Section III:Over-fitting, under-fittingNon-parametric learning algorithm: Local weighted regressionThe probability angle interprets the linear regression.

Extremely light of a semester finally passed, summer vacation intends to learn the big step down this machine learning techniques.The first lesson is the introduction of SVM, although I have learned it before, but I heard a feeling is very rewarding. The blogger sums up a ballpark figure, and the specifics areTo listen: http://www.cnblogs.com/bourneli/p/4198839.htmlThe blogger sums it up in detail: http://w

Open Course address: https://class.coursera.org/ml-003/class/index INSTRUCTOR: Andrew Ng1. unsupervised learning introduction (Introduction to unsupervised learning) We mentioned one of the two main branches of machine learning-supervised

hypothesis closest to F and F. Although it is possible that a dataset with 10 points can get a better approximation than a dataset with 2 points, when we have a lot of datasets, then their mathematical expectations should be close and close to F, so they are displayed as a horizontal line parallel to the X axis. The following is an example of a learning curve: See the following linear model: Why add noise? That is the interference. The purpose is to

: One-to-multiple ) Sometimes the problem is not as simple as determining whether a patient's tumor is malignant or benign. For example, determining whether the weather is sunny, cloudy, raining, Or snowing is necessary. We can use a line to separate binary classification. What about multiclass classification? There is a simple method, that is, to separate only one category at a time. There are several categories to construct several decision edge, that is, severalH (x): In th

dimension.Finally, we propose a method for solving overfitting, including data cleaning/pruning, data hinting, regularization (regularization), confirmation (validation), andTo drive for example to illustrate the role of these methods, the latter two methods are also the contents of the following two lessons.Data cleaning/pruning is to correct or delete the wrong sample points, processing is simple, but usually such sample points are not easy to find.Data hinting generate more sample numbers by

This section is about regularization, in the optimization of the use of regularization, in class when the teacher a word, not too much explanation. After listening to this class,To understand the difference between a good university and a pheasant university. In short, this is a very rewarding lesson.First of all, we introduce the reason for regularization, simply say that the complex model with a simple model to express, as to how to say, there is a series of deduction hypothesis, very creative

Netfei is a DVD leasing company. by increasing its sales by 10%, it can earn 1 million RMB in revenue, which is very impressive. How to: predict consumers' ratings for movies? (Increase the predicted value by 10 percentage points through their own systems) if the recommendations you provide to consumers are very accurate, the consumers will be very satisfied. The essence of machine learning: 1. An existin

23:55:01 | category: foreign university courses | Tag: machine learning | font size subscription INSTRUCTOR: Andrew Ng Http://see.stanford.edu/see/courseinfo.aspx? Coll = 348ca38a-3a6d-4052-937d-cb017338d7b1 Http://www.stanford.edu/class/cs229/materials.html Lecture Notes 1 (PS) (PDF) Supervised Learning, discriminative algorithms Lecture

(\theta) =-\frac{1}{m} \sum\limits_{i=1}^{m}\left[y^{(i)}\log (H_\theta (x^{(i)}) + (1-y^{(i)}) \log (1-h_\ Theta (x^{(i)})) \right] + \frac{\lambda}{2m}\sum\limits_{j=1}^{n}\theta_j^{2}$$Gradient Descent parameter update:$$\theta_0 = \theta_0-\alpha\frac{1}{m}\sum\limits_{i=1}^{m} (H_\theta (x^{(i)})-y^{(i)}) x_0^{(i)}; j = 0$$$$\theta_j = \theta_j-\alpha \left[\frac{1}{m}\sum\limits_{i=1}^{m} (H_\theta (x^{(i)})-y^{(i)}) x_j^{(i)} + \frac{\ Lambda}{m}\theta_j \right]; J > 1$$Reference documen

Translator Note : This article is translated from the Stanford cs231n Course Note convnet notes, which is authorized by the curriculum teacher Andrej Karpathy. This tutorial is completed by Duke and monkey translators, Kun kun and Li Yiying for proofreading and revision.The original text is as follows Content list: structure Overview A variety of layers used to build a convolution neural networkThe dimension setting regularity of the arrangement law l

I've been talking about why machines can learn, and starting with this lesson are some basic machine learning algorithms, i.e. how machines learn.This lesson is about linear regression, starting with the minimization of Ein, introducing the Hat Matrix to understand the geometric meaning. Finally, the linear regression and binary classification are compared, and the reason why linear regression can be used t

reduced after removing the label, (2) using the data of the reduced dimension to train the model, (3) for the new data points, the PCA reduced dimension to obtain the dimensionality reduction data, and the model to obtain the predicted value. Note : You should only use the training set data for PCA dimensionality reduction get Map $x^{(i)}\rightarrow z^{(i)}$, and then apply the mapping (PCA-selected principal matrix $u_reduce$) to the validation set and test set do not use PCA to block ove

ADD1 () DROP1 () 9. Regression Diagnostics Does the sample conform to the normal distribution? Normality test: function shapiro.test (X$X1) The distribution of normality Learning set/Is there outliers? How to find Outliers is the linear model reasonable? Maybe the relationship between nature is more complicated. Whether the error satisfies the independence, equal variance (the error is no

classifier will be severely affected, as shown in:To solve the above two problems, we adjust the optimization problem to:Note: When ξ>1, it is possible to allow the classification to be wrong, and then we add the ξ as a penalty to the target function.Using Lagrange duality again, we get the duality problem as:Surprisingly, after adding the L1 regularization item, only a αi≤c is added to the like limit in the dual problem. Note that the b* calculation needs to be changed (see Platt's paper)KKT d

This is what we have learned (except decision tree)Here is a typical decision tree algorithm, with four places to choose from:Then introduced a cart algorithm: By decision Stump divided into two categories, the criterion for measuring subtree is that the data are divided into two categories, the purity of these two types of data (purifying).The following is a measure of purity:Finally, when to stop:Decision tree may be overfitting, reducing the number of Ein and leaves (indicating the complexity

In this section, a linear model is introduced, and several linear models are compared, and the linear regression and the logistic regression are used for classification by the conversion error function.More important is this diagram, which explains why you can use linear regression or a logistic regression to replace linear classificationThen the stochastic gradient descent method is introduced, which is an improvement to the gradient descent method, which greatly improves the efficiency.Finally

This section is about the nuclear svm,andrew Ng's handout, which is also well-spoken.The first is kernel trick, which uses nuclear techniques to simplify the calculation of low-dimensional features by mapping high-dimensional features. The handout also speaks of the determination of the kernel function, that is, what function K can use kernel trick.In addition, the kernel function can measure the similarity of two features, the greater the value, the more similar.Next is the polynomial Kernel, w

slowly; conversely, if it is too large, the algorithm may miss the minimum value, or even not converge. Another thing to note is that, above $\theta_0, \theta_1$ 's update formula uses all the data in the dataset (called "Batch" Gradient descent), which means that for every update, we have to scan the entire data set, Causes the update to be too slow.Review of linear algebra Matrix and Vector definitions Matrix addition and multiplication Matrix-Vector Product Matrix-matrix