Nearest Neighbor Methods
Recommender Systems from Learned Embeddings
We will use Movie ID and User ID to generate their corresponding embeddings. These embeddings are generated through the model training process along with other parameters. Once we have the embeddings, we build a K-Nearest Neighbor (KNN) model. Then whenever there is a user, we can get that user's embedding from our Neural Network model. We use this embedding to lookup in the KNN database and recommend top -- K movies to this user.
Overcoming an Imbalanced Dataset using Oversampling.
How oversampling yielded great results for classifying cases of Sexual Harassment. When it comes to data science, sexual harassment is an imbalanced data problem, meaning there are few (known) instances of harassment in the entire dataset. An imbalanced problem is defined as a dataset which has disproportional class counts. Oversampling is one way to combat this by creating synthetic minority samples. SMOTE -- Synthetic Minority Over-sampling Technique -- is a common oversampling method widely used in machine learning with imbalanced high-dimensional datasets using Oversampling.
9 Key Machine Learning Algorithms Explained in Plain English
Machine learning [https://gum.co/pGjwd] is changing the world. Google uses machine learning to suggest search results to users. Netflix uses it to recommend movies for you to watch. Facebook uses machine learning to suggest people you may know. Machine learning has never been more important. At the same time, understanding machine learning is hard. The field is full of jargon. And the number of different ML algorithms grows each year. This article will introduce you to the fundamental concepts
K-Nearest Neighbors (KNN) Algorithm In Machine Learning
K-Nearest Neighbors (KNN) Algoritm in Machine Learning will help you to master all the concepts of KNN. KNN algorithm is one of the simplest, non-parametric, lazy classification learning algorithm. Its purpose is to use a dataset in which the data points are separated into several classes to predict the classification of a new sample point. This tutorial on "KNN Algoritm in Machine Learning" will help you to master all the concepts of K-nearest neighbors. Its purpose is to use a dataset in which the data points are separated into several classes to predict the classification of a new sample point.
An Efficient Data Imputation Technique for Human Activity Recognition
Pires, Ivan Miguel, Hussain, Faisal, Garcia, Nuno M., Zdravevski, Eftim
The tremendous applications of human activity recognition are surging its span from health monitoring systems to virtual reality applications. Thus, the automatic recognition of daily life activities has become significant for numerous applications. In recent years, many datasets have been proposed to train the machine learning models for efficient monitoring and recognition of human daily living activities. However, the performance of machine learning models in activity recognition is crucially affected when there are incomplete activities in a dataset, i.e., having missing samples in dataset captures. Therefore, in this work, we propose a methodology for extrapolating the missing samples of a dataset to better recognize the human daily living activities. The proposed method efficiently pre-processes the data captures and utilizes the k-Nearest Neighbors (KNN) imputation technique to extrapolate the missing samples in dataset captures. The proposed methodology elegantly extrapolated a similar pattern of activities as they were in the real dataset.
Understanding Machine learning
Artificial intelligence is everywhere in the press. Machine learning is everywhere in companies. What is the link between these three disciplines, and above all, what differentiates them? Indeed, in the common imagination, when we talk about artificial intelligence, we mean by this a program that can perform human tasks, learning on its own. However, AI as defined in the industry is rather "more or less advanced algorithms which imitate human actions".
Missing Features Reconstruction Using a Wasserstein Generative Adversarial Imputation Network
Friedjungovรก, Magda, Vaลกata, Daniel, Balatsko, Maksym, Jiลina, Marcel
Missing data is one of the most common preprocessing problems. In this paper, we experimentally research the use of generative and non-generative models for feature reconstruction. Variational Autoencoder with Arbitrary Conditioning (VAEAC) and Generative Adversarial Imputation Network (GAIN) were researched as representatives of generative models, while the denoising autoencoder (DAE) represented non-generative models. Performance of the models is compared to traditional methods k-nearest neighbors (k-NN) and Multiple Imputation by Chained Equations (MICE). Moreover, we introduce WGAIN as the Wasserstein modification of GAIN, which turns out to be the best imputation model when the degree of missingness is less than or equal to 30%. Experiments were performed on real-world and artificial datasets with continuous features where different percentages of features, varying from 10% to 50%, were missing. Evaluation of algorithms was done by measuring the accuracy of the classification model previously trained on the uncorrupted dataset. The results show that GAIN and especially WGAIN are the best imputers regardless of the conditions. In general, they outperform or are comparative to MICE, k-NN, DAE, and VAEAC.
Dex-Net AR uses Apple's ARKit to train robots to grasp objects
UC Berkeley AI researchers are using an iPhone X and Apple's ARKit to train a robotic arm how to grasp an object. ARKit creates point clouds from data generated by moving an RGB camera around an object for two minutes. Robotic grasping is a particular robotics subfield focused on the challenge of teaching a robot to pick up, move, manipulate, or grasp an object. The Dexterity Network, or Dex-Net, research project at UC Berkeley's Autolab dates back to 2017 and includes open source training data sets and pretrained models for robotic grasping in an ecommerce bin-picking scenario. The ability for robots to quickly learn how to grasp objects has a big impact on how automated warehouses like Amazon fulfillment centers can become.
Smartphone Transportation Mode Recognition Using a Hierarchical Machine Learning Classifier and Pooled Features From Time and Frequency Domains
Ashqar, Huthaifa I., Almannaa, Mohammed H., Elhenawy, Mohammed, Rakha, Hesham A., House, Leanna
This paper develops a novel two-layer hierarchical classifier that increases the accuracy of traditional transportation mode classification algorithms. This paper also enhances classification accuracy by extracting new frequency domain features. Many researchers have obtained these features from global positioning system data; however, this data was excluded in this paper, as the system use might deplete the smartphone's battery and signals may be lost in some areas. Our proposed two-layer framework differs from previous classification attempts in three distinct ways: 1) the outputs of the two layers are combined using Bayes' rule to choose the transportation mode with the largest posterior probability; 2) the proposed framework combines the new extracted features with traditionally used time domain features to create a pool of features; and 3) a different subset of extracted features is used in each layer based on the classified modes. Several machine learning techniques were used, including k-nearest neighbor, classification and regression tree, support vector machine, random forest, and a heterogeneous framework of random forest and support vector machine. Results show that the classification accuracy of the proposed framework outperforms traditional approaches. Transforming the time domain features to the frequency domain also adds new features in a new space and provides more control on the loss of information. Consequently, combining the time domain and the frequency domain features in a large pool and then choosing the best subset results in higher accuracy than using either domain alone. The proposed two-layer classifier obtained a maximum classification accuracy of 97.02%.
Towards Certified Robustness of Metric Learning
Yang, Xiaochen, Guo, Yiwen, Dong, Mingzhi, Xue, Jing-Hao
Metric learning aims to learn a distance metric such that semantically similar instances are pulled together while dissimilar instances are pushed away. Many existing methods consider maximizing or at least constraining a distance "margin" that separates similar and dissimilar pairs of instances to guarantee their performance on a subsequent k-nearest neighbor classifier. However, such a margin in the feature space does not necessarily lead to robustness certification or even anticipated generalization advantage, since a small perturbation of test instance in the instance space could still potentially alter the model prediction. To address this problem, we advocate penalizing small distance between training instances and their nearest adversarial examples, and we show that the resulting new approach to metric learning enjoys a larger certified neighborhood with theoretical performance guarantee. Moreover, drawing on an intuitive geometric insight, the proposed new loss term permits an analytically elegant closed-form solution and offers great flexibility in leveraging it jointly with existing metric learning methods. Extensive experiments demonstrate the superiority of the proposed method over the state-of-the-arts in terms of both discrimination accuracy and robustness to noise.