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 Statistical Learning


Transferable Neural Processes for Hyperparameter Optimization

arXiv.org Artificial Intelligence

Automated machine learning aims to automate the whole process of machine learning, including model configuration. In this paper, we focus on automated hyperparameter optimization (HPO) based on sequential model-based optimization (SMBO). Though conventional SMBO algorithms work well when abundant HPO trials are available, they are far from satisfactory in practical applications where a trial on a huge dataset may be so costly that an optimal hyperparameter configuration is expected to return in as few trials as possible. Observing that human experts draw on their expertise in a machine learning model by trying configurations that once performed well on other datasets, we are inspired to speed up HPO by transferring knowledge from historical HPO trials on other datasets. We propose an end-to-end and efficient HPO algorithm named as Transfer Neural Processes (TNP), which achieves transfer learning by incorporating trials on other datasets, initializing the model with well-generalized parameters, and learning an initial set of hyperparameters to evaluate. Experiments on extensive OpenML datasets and three computer vision datasets show that the proposed model can achieve state-of-the-art performance in at least one order of magnitude less trials.


From the Token to the Review: A Hierarchical Multimodal approach to Opinion Mining

arXiv.org Artificial Intelligence

The task of predicting fine grained user opinion based on spontaneous spoken language is a key problem arising in the development of Computational Agents as well as in the development of social network based opinion miners. Unfortunately, gathering reliable data on which a model can be trained is notoriously difficult and existing works rely only on coarsely labeled opinions. In this work we aim at bridging the gap separating fine grained opinion models already developed for written language and coarse grained models developed for spontaneous multimodal opinion mining. We take advantage of the implicit hierarchical structure of opinions to build a joint fine and coarse grained opinion model that exploits different views of the opinion expression. The resulting model shares some properties with attention-based models and is shown to provide competitive results on a recently released multimodal fine grained annotated corpus.


Diabetes Prediction with Ensemble Techniques

#artificialintelligence

Here, for this data we will build models to predict the "Outcome" i.e. Diabetes Yes or No and we will perform Ensemble techniques to better our predictions. We will be using several techniques to do that, each technique is briefed as we keep building our codes below. Here is the link to this data from where it can be downloaded.


Python Libraries for Interpretable Machine Learning

#artificialintelligence

As concerns regarding bias in artificial intelligence become more prominent it is becoming more and more important for businesses to be able to explain both the predictions their models are producing and how the models themselves work. Fortunately, there is an increasing number of python libraries being developed that attempt to solve this problem. In the following post, I am going to give a brief guide to four of the most established packages for interpreting and explaining machine learning models. The following libraries are all pip installable, come with good documentation and have an emphasis on visual interpretation. This library is essentially an extension of the scikit-learn library and provides some really useful and pretty looking visualisations for machine learning models.


Exercise Classification with Machine Learning (Part I)

#artificialintelligence

The first post will focus on a more algorithmic approach using k-Nearest Neighbors to classify an unknown video, and in the second post, we'll look at an exclusively machine learning (ML) approach. Code for everything we're going to cover can be found on this GitHub repository. The algorithmic approach (Part I) is written in Swift and is available as a CocoaPod. The ML approach (Part II) is written in Python/TensorFlow and can be found as part of the GitHub repository. We want to build a system which takes as input a video of a person performing an exercise and outputs a class label which describes the video.


On Education A-Z Machine Learning using Azure Machine Learning (AzureML) - all courses

#artificialintelligence

Understand the concepts and intuition of Machine Learning algorithms Build Machine Learning models within minutes Choose the correct Machine Learning Algorithm using the cheatsheet Deploy production grade Machine Learning algorithms Deploy Machine Learning webservices in the simplest form possible including excel Bring in great value to business you manage Basic Math is good enough. This course does not require background in Data Science. Will be great if you have one. Free or paid subscription to Microsoft Azure is required. It may ask for Phone and/or Credit Card for verification Machine Learning is one of the hottest and top paying skills.


Machine learning accelerates parameter optimization and uncertainty assessment of a land surface model

arXiv.org Machine Learning

The performance of land surface models (LSMs) strongly depends on their unknown parameter variables so that it is necessary to optimize them. Here I present a globally applicable and computationally efficient method for parameter optimization and uncertainty assessment of the LSM by combining Markov Chain Monte Carlo (MCMC) with machine learning. First, I performed the long-term ensemble simulation of the LSM, in which each ensemble member has different parameters' variables, and calculated the gap between simulation and observation, or the cost function, for each ensemble member. Second, I developed the statistical machine learning based surrogate model, which is computationally cheap but accurately mimics the relationship between parameters and the cost function, by applying the Gaussian process regression to learn the model simulation. Third, we applied MCMC by repeatedly driving the surrogate model to get the posterior probabilistic distribution of parameters. Using satellite passive microwave brightness temperature observations, both synthetic and real-data experiments were performed to optimize unknown soil and vegetation parameters of the LSM. The primary findings are (1) the proposed method is 50,000 times as fast as the direct application of MCMC to the full LSM; (2) the skill of the LSM to simulate both soil moisture and vegetation dynamics can be improved; (3) I successfully quantify the characteristics of equifinality by obtaining the full non-parametric probabilistic distribution of parameters.


Super learning for daily streamflow forecasting: Large-scale demonstration and comparison with multiple machine learning algorithms

arXiv.org Machine Learning

Daily streamflow forecasting through data-driven approaches is traditionally performed using a single machine learning algorithm. Existing applications are mostly restricted to examination of few case studies, not allowing accurate assessment of the predictive performance of the algorithms involved. Here we propose super learning (a type of ensemble learning) by combining 10 machine learning algorithms. We apply the proposed algorithm in one-step ahead forecasting mode. For the application, we exploit a big dataset consisting of 10-year long time series of daily streamflow, precipitation and temperature from 511 basins. The super learner improves over the performance of the linear regression algorithm by 20.06%, outperforming the "hard to beat in practice" equal weight combiner. The latter improves over the performance of the linear regression algorithm by 19.21%. The best performing individual machine learning algorithm is neural networks, which improves over the performance of the linear regression algorithm by 16.73%, followed by extremely randomized trees (16.40%), XGBoost (15.92%), loess (15.36%), random forests (12.75%), polyMARS (12.36%), MARS (4.74%), lasso (0.11%) and support vector regression (-0.45%). Based on the obtained large-scale results, we propose super learning for daily streamflow forecasting.


DensePoint: Learning Densely Contextual Representation for Efficient Point Cloud Processing

arXiv.org Artificial Intelligence

Point cloud processing is very challenging, as the diverse shapes formed by irregular points are often indistinguishable. A thorough grasp of the elusive shape requires sufficiently contextual semantic information, yet few works devote to this. Here we propose DensePoint, a general architecture to learn densely contextual representation for point cloud processing. T echnically, it extends regular grid CNN to irregular point configuration by generalizing a convolution operator, which holds the permutation invariance of points, and achieves efficient inductive learning of local patterns. Architecturally, it finds inspiration from dense connection mode, to repeatedly aggregate multilevel and multi-scale semantics in a deep hierarchy. As a result, densely contextual information along with rich semantics, can be acquired by DensePoint in an organic manner, making it highly effective. Extensive experiments on challenging benchmarks across four tasks, as well as thorough model analysis, verify DensePoint achieves the state of the arts.


Predicting intelligence based on cortical WM/GM contrast, cortical thickness and volumetry

arXiv.org Machine Learning

We propose a four-layer fully-connected neural network (FNN) for predicting fluid intelligence scores from T1-weighted MR images for the ABCD-challenge. In addition to the volumes of brain structures, the FNN uses cortical WM/GM contrast and cortical thickness at 78 cortical regions. These last two measurements were derived from the T1-weighted MR images using cortical surfaces produced by the CIVET pipeline. The age and gender of the subjects and the scanner manufacturer are also used as features for the learning algorithm. This yielded 283 features provided to the FNN with two hidden layers of 20 and 15 nodes. The method was applied to the data from the ABCD study. Trained with a training set of 3736 subjects, the proposed method achieved a MSE of 71.596 and a correlation of 0.151 in the validation set of 415 subjects. For the final submission, the model was trained with 3568 subjects and it achieved a MSE of 94.0270 in the test set comprised of 4383 subjects.