Statistical Learning
Generalized vec trick for fast learning of pairwise kernel models
Viljanen, Markus, Airola, Antti, Pahikkala, Tapio
Pairwise learning corresponds to the supervised learning setting where the goal is to make predictions for pairs of objects. Prominent applications include predicting drug-target or protein-protein interactions, or customer-product preferences. Several kernel functions have been proposed for incorporating prior knowledge about the relationship between the objects, when training kernel based learning methods. However, the number of training pairs n is often very large, making O(n^2) cost of constructing the pairwise kernel matrix infeasible. If each training pair x= (d,t) consists of drug d and target t, let m and q denote the number of unique drugs and targets appearing in the training pairs. In many real-world applications m,q << n, which can be used to develop computational shortcuts. Recently, a O(nm+nq) time algorithm we refer to as the generalized vec trick was introduced for training kernel methods with the Kronecker kernel. In this work, we show that a large class of pairwise kernels can be expressed as a sum of product matrices, which generalizes the result to the most commonly used pairwise kernels. This includes symmetric and anti-symmetric, metric-learning, Cartesian, ranking, as well as linear, polynomial and Gaussian kernels. In the experiments, we demonstrate how the introduced approach allows scaling pairwise kernels to much larger data sets than previously feasible, and compare the kernels on a number of biological interaction prediction tasks.
Travel time prediction for congested freeways with a dynamic linear model
Kwak, Semin, Geroliminis, Nikolas
Accurate prediction of travel time is an essential feature to support Intelligent Transportation Systems (ITS). The non-linearity of traffic states, however, makes this prediction a challenging task. Here we propose to use dynamic linear models (DLMs) to approximate the non-linear traffic states. Unlike a static linear regression model, the DLMs assume that their parameters are changing across time. We design a DLM with model parameters defined at each time unit to describe the spatio-temporal characteristics of time-series traffic data. Based on our DLM and its model parameters analytically trained using historical data, we suggest an optimal linear predictor in the minimum mean square error (MMSE) sense. We compare our prediction accuracy of travel time for freeways in California (I210-E and I5-S) under highly congested traffic conditions with those of other methods: the instantaneous travel time, k-nearest neighbor, support vector regression, and artificial neural network. We show significant improvements in the accuracy, especially for short-term prediction.
Supervised Topological Maps
Controlling the internal representation space of a neural network is a desirable feature because it allows to generate new data in a supervised manner. In this paper we will show how this can be achieved while building a low-dimensional mapping of the input stream, by deriving a generalized algorithm starting from Self Organizing Maps (SOMs). SOMs are a kind of neural network which can be trained with unsupervised learning to produce a low-dimensional discretized mapping of the input space. They can be used for the generation of new data through backward propagation of interpolations made from the mapping grid. Unfortunately the final topology of the mapping space of a SOM is not known before learning, so interpolating new data in a supervised way is not an easy task. Here we will show a variation from the SOM algorithm consisting in constraining the update of prototypes so that it is also a function of the distance of its prototypes from extrinsically given targets in the mapping space. We will demonstrate how such variants, that we will call Supervised Topological Maps (STMs), allow for a supervised mapping where the position of internal representations in the mapping space is determined by the experimenter. Controlling the internal representation space in STMs reveals to be an easier task than what is currently done using other algorithms such as variational or adversarial autoencoders.
A Machine Learning Approach to Assess Student Group Collaboration Using Individual Level Behavioral Cues
Som, Anirudh, Kim, Sujeong, Lopez-Prado, Bladimir, Dhamija, Svati, Alozie, Nonye, Tamrakar, Amir
K-12 classrooms consistently integrate collaboration as part of their learning experiences. However, owing to large classroom sizes, teachers do not have the time to properly assess each student and give them feedback. In this paper we propose using simple deep-learning-based machine learning models to automatically determine the overall collaboration quality of a group based on annotations of individual roles and individual level behavior of all the students in the group. We come across the following challenges when building these models: 1) Limited training data, 2) Severe class label imbalance. We address these challenges by using a controlled variant of Mixup data augmentation, a method for generating additional data samples by linearly combining different pairs of data samples and their corresponding class labels. Additionally, the label space for our problem exhibits an ordered structure. We take advantage of this fact and also explore using an ordinal-cross-entropy loss function and study its effects with and without Mixup.
Identifying Statistical Bias in Dataset Replication
Engstrom, Logan, Ilyas, Andrew, Santurkar, Shibani, Tsipras, Dimitris, Steinhardt, Jacob, Madry, Aleksander
The primary objective of supervised learning is to develop models that generalize robustly to unseen data. Benchmark test sets provide a proxy for out-of-sample performance, but can outlive their usefulness in some cases. For example, evaluating on benchmarks alone may steer us towards models that adaptively overfit [Reu03; RFR08; Dwo 15] to the finite test set and do not generalize. Alternatively, we might select for models that are sensitive to insignificant aspects of the dataset creation process and thus do not generalize robustly (e.g., models that are sensitive to the exact set of humans who annotated the test set). To diagnose these issues, recent work has generated new, previously "unseen" testbeds for standard datasets through a process known as dataset replication. Though not yet widespread in machine learning, dataset replication is a natural analogue to experimental replication studies in the natural sciences (cf.
Video Captioning Using Weak Annotation
Hou, Jingyi, Jia, Yunde, wu, Xinxiao, Qi, Yayun
Video captioning has shown impressive progress in recent years. One key reason of the performance improvements made by existing methods lie in massive paired video-sentence data, but collecting such strong annotation, i.e., high-quality sentences, is time-consuming and laborious. It is the fact that there now exist an amazing number of videos with weak annotation that only contains semantic concepts such as actions and objects. In this paper, we investigate using weak annotation instead of strong annotation to train a video captioning model. To this end, we propose a progressive visual reasoning method that progressively generates fine sentences from weak annotations by inferring more semantic concepts and their dependency relationships for video captioning. To model concept relationships, we use dependency trees that are spanned by exploiting external knowledge from large sentence corpora. Through traversing the dependency trees, the sentences are generated to train the captioning model. Accordingly, we develop an iterative refinement algorithm that refines sentences via spanning dependency trees and fine-tunes the captioning model using the refined sentences in an alternative training manner. Experimental results demonstrate that our method using weak annotation is very competitive to the state-of-the-art methods using strong annotation.
Learn Data Science, Deep Learning, Machine Learning, NLP & R
Get Udemy Coupon Code New What you'll learn Mathematics and Statistics behind Machine Learning Mathematics and Statistics behind Deep Learning Mathematics and Statistics behind Artificial Intelligence Python Programming Language from Scratch Python with it's Libraries Learn Numpy, Pandas, Matplotlib, Scikit-Learn Learn Natural Language Processing Learn Tokenization in Natural Language Processing Learn Implementation of R Packages and Libraries on Different Data Sets Learn Implementation of Python Libraries on Different Data Sets Algorithms and Models of Machine Learning Algorithms and Models of Deep Learning k-Nearest Neighbors, Naive Bayes etc Supervised and Unsupervised Learning Description DATA SCIENCE Data science continues to evolve as one of the most promising and in-demand career paths for skilled professionals. Today, successful data professionals understand that they must advance past the traditional skills of analyzing large amounts of data, data mining, and programming skills. What Does a Data Scientist Do? In the past decade, data scientists have become necessary assets and are present in almost all organizations. These professionals are well-rounded, data-driven individuals with high-level technical skills who are capable of building complex quantitative algorithms to organize and synthesize large amounts of information used to answer questions and drive strategy in their organization.
Learn Regression Analysis for Business
A complete hands on practical exercises to build regression models that are highly used for business analysis. This course is designed to start with the very basics then add up information gradually. Accordingly students who have fair background in regression analysis can choose to jump to the practical part of the course to learn building regression models in detail. In this course you will learn about different types of regression models and learn to build and use the ones used in business analysis. You will learn step by step how to understand a business problem from data observations and determine the variables you need to include in regression analysis.
Gradient Descent Optimization Techniques.
Gradient descent is one of the most popular algorithms to perform optimization and by far the most common way to optimize neural networks. At the same time, every state-of-the-art Deep Learning library contains implementations of various algorithms to optimize gradient descent . This blog post aims at providing you with intuitions towards the behaviour of different algorithms for optimizing gradient descent that will help you put them to use. Gradient descent is a way to minimize an objective function J(θ) parameterized by a model's parameters by updating the parameters in the opposite direction of the gradient of the objective function .J(θ) w.r.t. to the parameters. The learning rate η determines the size of the steps we take to reach a (local) minimum.
13 Algorithms and 4 Learning Methods of Machine Learning
According to the similarity of the function and form of the algorithm, we can classify the algorithm, such as tree-based algorithm, neural network-based algorithm, and so on. Of course, the scope of machine learning is very large, and it is difficult for some algorithms to be clearly classified into a certain category. Regression algorithm is a type of algorithm that tries to explore the relationship between variables by using a measure of error. Regression algorithm is a powerful tool for statistical machine learning. In the field of machine learning, when people talk about regression, sometimes they refer to a type of problem and sometimes a type of algorithm.