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 Nearest Neighbor Methods


K-Nearest Neighbor classification using python

@machinelearnbot

A number of open-source communities are using python to make available artificial intelligence and machine learning related packages and libraries. In this blog I will use libraries from scikit-learn. Project scikit-learn is a Machine Learning Project in Python. It has a good collection of algorithms for some of the well known data-mining and data analysis jobs such as for Classification, Regression, Clustering, Dimensionality reduction and Model Selection. These algorithms are constructed on a stack of NumPy, SciPy library, and matplotlib.


Handling imbalanced dataset in supervised learning using family of SMOTE algorithm.

#artificialintelligence

The algorithm adaptively updates the distribution and there are no assumptions made for the underlying distribution of the data. The algorithm uses Euclidean distance for KNN Algorithm. The key difference between ADASYN and SMOTE is that the former uses a density distribution, as a criterion to automatically decide the number of synthetic samples that must be generated for each minority sample by adaptively changing the weights of the different minority samples to compensate for the skewed distributions. The latter generates the same number of synthetic samples for each original minority sample.


Faiss: A library for efficient similarity search

#artificialintelligence

This month, we released Facebook AI Similarity Search (Faiss), a library that allows us to quickly search for multimedia documents that are similar to each other -- a challenge where traditional query search engines fall short. We've built nearest-neighbor search implementations for billion-scale data sets that are some 8.5x faster than the previous reported state-of-the-art, along with the fastest k-selection algorithm on the GPU known in the literature. This lets us break some records, including the first k-nearest-neighbor graph constructed on 1 billion high-dimensional vectors. Traditional databases are made up of structured tables containing symbolic information. For example, an image collection would be represented as a table with one row per indexed photo.


A to Z of Analytics

@machinelearnbot

Artificial Intelligence:: AI is the capability of a machine to imitate intelligent human behavior. BMW, Tesla, Google are using AI for self-driving cars. AI should be used to solve real world tough problems like climate modeling to disease analysis and betterment of humanity. Boosting and Bagging: it is the technique used to generate more accurate models by ensembling multiple models together Crisp-DM: is the cross industry standard process for data mining. It was developed by a consortium of companies like SPSS, Teradata, Daimler and NCR Corporation in 1997 to bring the order in developing analytics models.


Adaptive Neighboring Selection Algorithm Based on Curvature Prediction in Manifold Learning

arXiv.org Machine Learning

Recently manifold learning algorithm for dimensionality reduction attracts more and more interests, and various linear and nonlinear, global and local algorithms are proposed. The key step of manifold learning algorithm is the neighboring region selection. However, so far for the references we know, few of which propose a generally accepted algorithm to well select the neighboring region. So in this paper, we propose an adaptive neighboring selection algorithm, which successfully applies the LLE and ISOMAP algorithms in the test. It is an algorithm that can find the optimal K nearest neighbors of the data points on the manifold. And the theoretical basis of the algorithm is the approximated curvature of the data point on the manifold. Based on Riemann Geometry, Jacob matrix is a proper mathematical concept to predict the approximated curvature. By verifying the proposed algorithm on embedding Swiss roll from R3 to R2 based on LLE and ISOMAP algorithm, the simulation results show that the proposed adaptive neighboring selection algorithm is feasible and able to find the optimal value of K, making the residual variance relatively small and better visualization of the results. By quantitative analysis, the embedding quality measured by residual variance is increased 45.45% after using the proposed algorithm in LLE.


Machine Learning in R for beginners

#artificialintelligence

Machine learning is a branch in computer science that studies the design of algorithms that can learn. Typical machine learning tasks are concept learning, function learning or "predictive modeling", clustering and finding predictive patterns. These tasks are learned through available data that were observed through experiences or instructions, for example. Machine learning hopes that including the experience into its tasks will eventually improve the learning. The ultimate goal is to improve the learning in such a way that it becomes automatic, so that humans like ourselves don't need to interfere any more. This small tutorial is meant to introduce you to the basics of machine learning in R: more specifically, it will show you how to use R to work with the well-known machine learning algorithm called "KNN" or k-nearest neighbors. Additionally, this tutorial also covers how to use caret do to machine learning in R. If you're interested in following a course, consider checking out our Introduction to Machine Learning with R or DataCamp's Unsupervised Learning in R course! The KNN or k-nearest neighbors algorithm is one of the simplest machine learning algorithms and is an example of instance-based learning, where new data are classified based on stored, labeled instances.


K-Nearest Neighbors on Wisconsin Breast Cancer Data

#artificialintelligence

First, let's set things up in R by loading the necessary package and importing the data into R. the class package will be used to run the k-nearest neighbors algorithm. We will also use a specific seed so that you can reproduce this in R yourself. Importing the data, let's take a look at the basic structure of the dataset. The first variable, id, is there simply as a unique identifier for each observation. We will take it out for the purposes of our analysis.


Fast k-Nearest Neighbour Search via Dynamic Continuous Indexing

arXiv.org Artificial Intelligence

Existing methods for retrieving k-nearest neighbours suffer from the curse of dimensionality. We argue this is caused in part by inherent deficiencies of space partitioning, which is the underlying strategy used by most existing methods. We devise a new strategy that avoids partitioning the vector space and present a novel randomized algorithm that runs in time linear in dimensionality of the space and sub-linear in the intrinsic dimensionality and the size of the dataset and takes space constant in dimensionality of the space and linear in the size of the dataset. The proposed algorithm allows fine-grained control over accuracy and speed on a per-query basis, automatically adapts to variations in data density, supports dynamic updates to the dataset and is easy-to-implement. We show appealing theoretical properties and demonstrate empirically that the proposed algorithm outperforms locality-sensitivity hashing (LSH) in terms of approximation quality, speed and space efficiency.


A Bayes consistent 1-NN classifier

arXiv.org Machine Learning

We show that a simple modification of the 1-nearest neighbor classifier yields a strongly Bayes consistent learner. Prior to this work, the only strongly Bayes consistent proximity-based method was the k-nearest neighbor classifier, for k growing appropriately with sample size. We will argue that a margin-regularized 1-NN enjoys considerable statistical and algorithmic advantages over the k-NN classifier. These include user-friendly finite-sample error bounds, as well as time- and memory-efficient learning and test-point evaluation algorithms with a principled speed-accuracy tradeoff. Encouraging empirical results are reported.


Doing Machine Learning (K Nearest Neighbors) in a Messenger Chatbot

#artificialintelligence

Chatbots are taking over the world. Companies want them, developers are creating them, and more important, people are eager to try them. The use cases and experiences a chatbot can bring seem to be unlimited -- there are bots for managing group purchases, bots for helping people to obtain their immigration visas, and even bots for tracking flights. So, eventually the hype got me and I decided to build my first chatbot. My idea for this chatbot was to see how I could manually train and use a machine learning model through a chat-based interface, while trying several ideas and concepts that could enhance the experience of using a machine learning model in this way.