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Negative Log Likelihood Ratio Loss for Deep Neural Network Classification

arXiv.org Machine Learning

Deep neural network (DNN) has achieved remarkable success in classification tasks such as image classification [1]. The network output can mimic the posterior probabilities of target classes for the input observation when the nonlinear activation function in the output layer is defined as a soft-max function [2]. The learning objective is to minimize the difference between the predicted distribution and the true datagenerating distribution. In information theory, the cross entropy between two probability distributions over a common event set of events measures the average number of bits needed to identify an event if coding follows a learned probability distribution rather than the true but unknow distribution [3]. Therefore, cross entropy is a reasonable loss function for the DNN-based classification. However, in practice the true data-generating probability distribution is unknown and replaced by the empirical probability distribution over a training set where each sample is drawn independently and identically distributed (i.i.d.) from the data space [4]. Under assumptions of uniform distributions of feature and label spaces, minimizing cross-entropy is equivalent to maximum likelihood, i.e., the learning problem aims to maximize likelihood of correct class for each of training samples [2]. Maximum likelihood is a generative training criterion by which the model learns the likelihood of correct class for the observation. The model makes predictions by using Bayes rules to calculate posterior probabilities of target classes for the observation and then select the most likely class.


What You Must Know Before You Dive Into Machine Learning - DZone AI

#artificialintelligence

Machine learning refers to the process of enabling computer systems to learn with data using statistical techniques without being explicitly programmed. It is the process of active engagement with algorithms in order to enable them to learn from and make predictions on data. Machine learning is closely associated with computational statistics, mathematical optimization, and data learning. It is associated with predictive analysis, which allows producing reliable and fast results by learning from historical trends. Supervised learning: The computer is presented with some example inputs, based on which the desired outputs are to be formed.


Ethics Education in Data Science: Classroom Topics and Assignments

#artificialintelligence

The creation of ethics modules that can be inserted into a variety of classes may help ensure that ethics as a subject is not marginalized and enable professors with little experience in philosophy or with fewer resources to incorporate ethics into their more technical classes. This post will outline some of the topics that professors have decided to cover in this field, as well as suggestions for types of assignments that may be useful. We hope that readers will consider ways to add these into their classes, and we welcome comments with further suggestions of topics or assignments. With regards to ethics, some of the key topics that professors have taught about include: deontology, consequentialism, utilitarianism, virtue ethics, moral responsibility, cultural relativism, social contract, feminist ethics, justice consequentialism, the distinction between ethics and law, and the relationship between principles, standards, and rules. Using these frameworks, professors can discuss a variety of topics, including: privacy, algorithmic bias, misinformation, intellectual property, surveillance, inequality, data collection, AI governance, free speech, transparency, security, anonymity, systemic risk, labor, net neutrality, accessibility, value-sensitive design, codes of ethics, predictive policing, virtual reality, ethics in industry, machine learning, clinical versus actuarial reasoning, issue spotting, and basic social science concepts.


Belgium is right to legislate against video game 'loot boxes'

The Guardian

Yesterday, the Belgian minister of justice, Koen Greens, announced the result of an investigation that the country's Gaming Commission conducted into video game "loot boxes", a mechanic that lets players pay real money for a chance at winning virtual items. It found that three popular games โ€“ Overwatch, Counter-Strike: Global Offensive and Fifa 18 โ€“ were in violation of gambling legislation. This is a significant finding, because controversy over loot boxes has been raging for at least six months: are they actually a form of gambling? Worse, are they a form of gambling that is particularly appealing to children? Belgium's Gaming Commission has decided that, yes, they are, and the publishers in question should remove loot boxes from their games or face fines.


Scalable, Distributed, Deep Machine Learning for Big Data

#artificialintelligence

Apache Thrift The Thrift stack is a common class hierarchy implemented in each language that abstracts out the tricky details of protocol encoding and network communication 26. Chukwa A data collection system for monitoring large distributed systems; Provides flexible/powerful toolkit to display, monitor, and analyze results; Architecture: Agents - run on each machine and emit data; Collectors - receive data from the agent and write it to stable storage; MapReduce jobs - parsing and archiving the data; Hadoop Infrastructure Care Center - a web-portal style interface.


Machine Learning with TensorFlow on Google Cloud Platform Coursera

#artificialintelligence

What is machine learning, and what kinds of problems can it solve? What are the five phases of converting a candidate use case to be driven by machine learning, and why is it important that the phases not be skipped? Why are neural networks so popular now? How can you set up a supervised learning problem and find a good, generalizable solution using gradient descent and a thoughtful way of creating datasets? Learn how to write distributed machine learning models that scale in Tensorflow, scale out the training of those models.


Britain Pumps Cash Into Artificial Intelligence Before Brexit

U.S. News

Those funds will be matched by more than 300 million pounds of public funding, on top of an existing 400 million pound budget. The funds will be spent on teacher training, research and developing regional technology hubs to explore how AI can be used in industries such as law and insurance.


Handling Missing Values using Decision Trees with Branch-Exclusive Splits

arXiv.org Machine Learning

In this article we propose a new decision tree construction algorithm. The proposed approach allows the algorithm to interact with some predictors that are only defined in subspaces of the feature space. One way to utilize this new tool is to create or use one of the predictors to keep track of missing values. This predictor can later be used to define the subspace where predictors with missing values are available for the data partitioning process. By doing so, this new classification tree can handle missing values for both modelling and prediction. The algorithm is tested against simulated and real data. The result is a classification procedure that efficiently handles missing values and produces results that are more accurate and more interpretable than most common procedures.


Interactive Language Acquisition with One-shot Visual Concept Learning through a Conversational Game

arXiv.org Artificial Intelligence

Building intelligent agents that can communicate with and learn from humans in natural language is of great value. Supervised language learning is limited by the ability of capturing mainly the statistics of training data, and is hardly adaptive to new scenarios or flexible for acquiring new knowledge without inefficient retraining or catastrophic forgetting. We highlight the perspective that conversational interaction serves as a natural interface both for language learning and for novel knowledge acquisition and propose a joint imitation and reinforcement approach for grounded language learning through an interactive conversational game. The agent trained with this approach is able to actively acquire information by asking questions about novel objects and use the just-learned knowledge in subsequent conversations in a one-shot fashion. Results compared with other methods verified the effectiveness of the proposed approach.


Decentralized learning with budgeted network load using Gaussian copulas and classifier ensembles

arXiv.org Artificial Intelligence

We examine a network of learners which address the same classification task but must learn from different data sets. The learners can share a limited portion of their data sets so as to preserve the network load. We introduce DELCO (standing for Decentralized Ensemble Learning with COpulas), a new approach in which the shared data and the trained models are sent to a central machine that allows to build an ensemble of classifiers. The proposed method aggregates the base classifiers using a probabilistic model relying on Gaussian copulas. Experiments on logistic regressor ensembles demonstrate competing accuracy and increased robustness as compared to gold standard approaches. A companion python implementation can be downloaded at https://github.com/john-klein/DELCO