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 Decision Tree Learning


Logistic Regression, Decision Tree and Neural Network in R

@machinelearnbot

In this course, we cover two analytics techniques: Descriptive statistics and Predictive analytics. For the predictive analytic, our main focus is the implementation of a logistic regression model a Decision tree and neural network. We well also see how to interpret our result, compute the prediction accuracy rate, then construct a confusion matrix . By the end of this course, you will be able to effectively summarize your data, visualize your data, detect and eliminate missing values, predict futures outcomes using analytical techniques described above, construct a confusion matrix, import and export a data.


Hyperparameter Tuning the Random Forest in Python โ€“ Towards Data Science

#artificialintelligence

I have included Python code in this article where it is most instructive. Full code and data to follow along can be found on the project Github page. The best way to think about hyperparameters is like the settings of an algorithm that can be adjusted to optimize performance, just as we might turn the knobs of an AM radio to get a clear signal (or your parents might have!). While model parameters are learned during training -- such as the slope and intercept in a linear regression -- hyperparameters must be set by the data scientist before training. In the case of a random forest, hyperparameters include the number of decision trees in the forest and the number of features considered by each tree when splitting a node.


Transformation Forests

arXiv.org Machine Learning

Regression models for supervised learning problems with a continuous target are commonly understood as models for the conditional mean of the target given predictors. This notion is simple and therefore appealing for interpretation and visualisation. Information about the whole underlying conditional distribution is, however, not available from these models. A more general understanding of regression models as models for conditional distributions allows much broader inference from such models, for example the computation of prediction intervals. Several random forest-type algorithms aim at estimating conditional distributions, most prominently quantile regression forests (Meinshausen, 2006, JMLR). We propose a novel approach based on a parametric family of distributions characterised by their transformation function. A dedicated novel "transformation tree" algorithm able to detect distributional changes is developed. Based on these transformation trees, we introduce "transformation forests" as an adaptive local likelihood estimator of conditional distribution functions. The resulting models are fully parametric yet very general and allow broad inference procedures, such as the model-based bootstrap, to be applied in a straightforward way.


R Decision Trees - A Tutorial to Tree Based Modeling in R

@machinelearnbot

One of the most intuitive and popular methods of data mining that provides explicit rules for classification and copes well with heterogeneous data, missing data, and nonlinear effects is decision tree. It predicts the target value of an item by mapping observations about the item. You can perform either classification or regression tasks here. For example, identifying fraudulent transactions using credit cards would be a classification task while forecasting prices of stock would be regression task. Decision tree technique is used to detect the criteria for dividing individual items of a group into n predetermined classes (Often, n 2 represents a balanced tree, which means a largest of two child nodes for each parent node.) Firstly, a variable is taken as the root node.


Top 10 Machine Learning Algorithms for Beginners

#artificialintelligence

The study of ML algorithms has gained immense traction post the Harvard Business Review article terming a'Data Scientist' as the'Sexiest job of the 21st century'. So, for those starting out in the field of ML, we decided to do a reboot of our immensely popular Gold blog The 10 Algorithms Machine Learning Engineers need to know - albeit this post is targetted towards beginners. ML algorithms are those that can learn from data and improve from experience, without human intervention. Learning tasks may include learning the function that maps the input to the output, learning the hidden structure in unlabeled data; or'instance-based learning', where a class label is produced for a new instance by comparing the new instance (row) to instances from the training data, which were stored in memory. 'Instance-based learning' does not create an abstraction from specific instances. Supervised learning can be explained as follows: use labeled training data to learn the mapping function from the input variables (X) to the output variable (Y).


A Too-Clever Ranking Method

AI Magazine

I developed what I thought was an extremely clever method for detecting "bad" training instances. Each instance was scored, and those with the lowest scores could be removed before running C4.5 to build a decision tree with the remainder. I ran an experiment in which I removed the bottom 10 percent of the instances in a University of California, Irvine (UCI) data set. The resulting tree was smaller and more accurate (as measured by 10-fold CV) than the tree built on the full data set. Then I removed the bottom 20 percent of the instances and got a tree that was smaller than the last one and just as accurate.


The Strengths and Weaknesses of Modern Machine Learning Algorithms

#artificialintelligence

When it comes to today's machine learning algorithms, they are being used in a variety of ways as well as in different fields. Healthcare, businesses, research are just a few examples where artificial intelligence is being applied to solve problems that either humans could not do by themselves or would take massive amounts of time to solve. However, everything in life has its strengths and weaknesses; modern machine learning algorithms are unfortunately no exception to this rule. Earlier this year, an article posted on the Elite Data Science website focused on several types of today's modern machine learning algorithms as well as their strengths and weakness. Basically, there is no super algorithm that can solve every problem and that it would be an innovative idea to try a variety of algorithms to resolve the problem at hand.


Five steps to build better predictive analytics applications

#artificialintelligence

This approach to predictive analytics applications can be illustrated by an example. Let's consider an e-commerce company that wants to boost its profits by growing sales to existing customers. The objectives might be to increase both the number of items bought by individual customers and the average amount they spend overall in purchase transactions. A typical strategy to accomplish those goals involves using a recommendation engine to try to influence customers to add items to their online cart as they shop. There are a variety of different analytics methods that the online retailer can incorporate into its recommendation engine to assign similar customers to groups so the engine can suggest products that they might be inclined to buy.


Label Distribution Learning Forests

Neural Information Processing Systems

Label distribution learning (LDL) is a general learning framework, which assigns to an instance a distribution over a set of labels rather than a single label or multiple labels. Current LDL methods have either restricted assumptions on the expression form of the label distribution or limitations in representation learning, e.g., to learn deep features in an end-to-end manner. This paper presents label distribution learning forests (LDLFs) - a novel label distribution learning algorithm based on differentiable decision trees, which have several advantages: 1) Decision trees have the potential to model any general form of label distributions by a mixture of leaf node predictions. 2) The learning of differentiable decision trees can be combined with representation learning. We define a distribution-based loss function for a forest, enabling all the trees to be learned jointly, and show that an update function for leaf node predictions, which guarantees a strict decrease of the loss function, can be derived by variational bounding. The effectiveness of the proposed LDLFs is verified on several LDL tasks and a computer vision application, showing significant improvements to the state-of-the-art LDL methods.


Maximum Margin Interval Trees

Neural Information Processing Systems

Learning a regression function using censored or interval-valued output data is an important problem in fields such as genomics and medicine. The goal is to learn a real-valued prediction function, and the training output labels indicate an interval of possible values. Whereas most existing algorithms for this task are linear models, in this paper we investigate learning nonlinear tree models. We propose to learn a tree by minimizing a margin-based discriminative objective function, and we provide a dynamic programming algorithm for computing the optimal solution in log-linear time. We show empirically that this algorithm achieves state-of-the-art speed and prediction accuracy in a benchmark of several data sets.