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Optimally Combining Classifiers for Semi-Supervised Learning

arXiv.org Machine Learning

This paper considers semi-supervised learning for tabular data. It is widely known that Xgboost based on tree model works well on the heterogeneous features while transductive support vector machine can exploit the low density separation assumption. However, little work has been done to combine them together for the end-to-end semi-supervised learning. In this paper, we find these two methods have complementary properties and larger diversity, which motivates us to propose a new semi-supervised learning method that is able to adaptively combine the strengths of Xgboost and transductive support vector machine. Instead of the majority vote rule, an optimization problem in terms of ensemble weight is established, which helps to obtain more accurate pseudo labels for unlabeled data. The experimental results on the UCI data sets and real commercial data set demonstrate the superior classification performance of our method over the five state-of-the-art algorithms improving test accuracy by about $3\%-4\%$. The partial code can be found at https://github.com/hav-cam-mit/CTO.


FMA-ETA: Estimating Travel Time Entirely Based on FFN With Attention

arXiv.org Machine Learning

Estimated time of arrival (ETA) is one of the most important services in intelligent transportation systems and becomes a challenging spatial-temporal (ST) data mining task in recent years. Nowadays, deep learning based methods, specifically recurrent neural networks (RNN) based ones are adapted to model the ST patterns from massive data for ETA and become the state-of-the-art. However, RNN is suffering from slow training and inference speed, as its structure is unfriendly to parallel computing. To solve this problem, we propose a novel, brief and effective framework mainly based on feed-forward network (FFN) for ETA, FFN with Multi-factor self-Attention (FMA-ETA). The novel Multi-factor self-attention mechanism is proposed to deal with different category features and aggregate the information purposefully. Extensive experimental results on the real-world vehicle travel dataset show FMA-ETA is competitive with state-of-the-art methods in terms of the prediction accuracy with significantly better inference speed.


Fusion Recurrent Neural Network

arXiv.org Machine Learning

Considering deep sequence learning for practical application, two representative RNNs - LSTM and GRU may come to mind first. Nevertheless, is there no chance for other RNNs? Will there be a better RNN in the future? In this work, we propose a novel, succinct and promising RNN - Fusion Recurrent Neural Network (Fusion RNN). Fusion RNN is composed of Fusion module and Transport module every time step. Fusion module realizes the multi-round fusion of the input and hidden state vector. Transport module which mainly refers to simple recurrent network calculate the hidden state and prepare to pass it to the next time step. Furthermore, in order to evaluate Fusion RNN's sequence feature extraction capability, we choose a representative data mining task for sequence data, estimated time of arrival (ETA) and present a novel model based on Fusion RNN. We contrast our method and other variants of RNN for ETA under massive vehicle travel data from DiDi Chuxing. The results demonstrate that for ETA, Fusion RNN is comparable to state-of-the-art LSTM and GRU which are more complicated than Fusion RNN.


Soft Gradient Boosting Machine

arXiv.org Machine Learning

Gradient Boosting Machine has proven to be one successful function approximator and has been widely used in a variety of areas. However, since the training procedure of each base learner has to take the sequential order, it is infeasible to parallelize the training process among base learners for speed-up. In addition, under online or incremental learning settings, GBMs achieved sub-optimal performance due to the fact that the previously trained base learners can not adapt with the environment once trained. In this work, we propose the soft Gradient Boosting Machine (sGBM) by wiring multiple differentiable base learners together, by injecting both local and global objectives inspired from gradient boosting, all base learners can then be jointly optimized with linear speed-up. When using differentiable soft decision trees as base learner, such device can be regarded as an alternative version of the (hard) gradient boosting decision trees with extra benefits. Experimental results showed that, sGBM enjoys much higher time efficiency with better accuracy, given the same base learner in both on-line and off-line settings.


Growing Together: Modeling Human Language Learning With n-Best Multi-Checkpoint Machine Translation

arXiv.org Machine Learning

We describe our submission to the 2020 Duolingo Shared Task on Simultaneous Translation And Paraphrase for Language Education (STAPLE) (Mayhew et al., 2020). We view MT models at various training stages (i.e., checkpoints) as human learners at different levels. Hence, we employ an ensemble of multi-checkpoints from the same model to generate translation sequences with various levels of fluency. From each checkpoint, for our best model, we sample n-Best sequences (n=10) with a beam width =100. We achieve 37.57 macro F1 with a 6 checkpoint model ensemble on the official English to Portuguese shared task test data, outperforming a baseline Amazon translation system of 21.30 macro F1 and ultimately demonstrating the utility of our intuitive method.


Sharp Representation Theorems for ReLU Networks with Precise Dependence on Depth

arXiv.org Machine Learning

We prove sharp dimension-free representation results for neural networks with $D$ ReLU layers under square loss for a class of functions $\mathcal{G}_D$ defined in the paper. These results capture the precise benefits of depth in the following sense: 1. The rates for representing the class of functions $\mathcal{G}_D$ via $D$ ReLU layers is sharp up to constants, as shown by matching lower bounds. 2. For each $D$, $\mathcal{G}_{D} \subseteq \mathcal{G}_{D+1}$ and as $D$ grows the class of functions $\mathcal{G}_{D}$ contains progressively less smooth functions. 3. If $D^{\prime} < D$, then the approximation rate for the class $\mathcal{G}_D$ achieved by depth $D^{\prime}$ networks is strictly worse than that achieved by depth $D$ networks. This constitutes a fine-grained characterization of the representation power of feedforward networks of arbitrary depth $D$ and number of neurons $N$, in contrast to existing representation results which either require $D$ growing quickly with $N$ or assume that the function being represented is highly smooth. In the latter case similar rates can be obtained with a single nonlinear layer. Our results confirm the prevailing hypothesis that deeper networks are better at representing less smooth functions, and indeed, the main technical novelty is to fully exploit the fact that deep networks can produce highly oscillatory functions with few activation functions.


Future Tense Newsletter: A Very Tense Present

Slate

This past week, we witnessed wrenching debates over speech--involving protesters on the street, our Twitterer-in-chief, and aspiring New York Times op-ed writers. Some of the best tools we have to inspire and contextualize social movements are books and film, and in the next week, we will host conversations with some of the most interesting leaders in the book industry and Hollywood. We hope you'll join us: After a man is injured in a forklift accident, he takes on a lucrative offer to "raise" a robot. After a jarring first impression (imagine a toddler in the body of a massive robot), the relationship makes the protagonist rethink much of his life. In the response essay, John Frank Weaver, author of Robots Are People Too warns about the manipulative capabilities of all-too-human robots: "A company that records all your interactions raising a child--the stress, the exhaustion, the jubilation, the love--has a treasure trove of information about what makes you tick as a person, even when the child is a robot."


Free data science ebooks for June 2019

#artificialintelligence

The book is about quickly entering the world of creating machine learning models in R. The theory is kept to minimum and there are examples for each of the major algorithms for classification, clustering, features engineering and association rules. The book is a compilation of the leaflets the authors give to their students during the practice labs, in the courses of Pattern Recognition and Data Mining, in the Electrical and Computer Engineering Department of the Aristotle University of Thessaloniki.


Latam artificial intelligence startups in the fight against more than Covid-19

#artificialintelligence

Don't worry, we speak: Espaรฑol (Spanish), too! Contxto โ€“ Artificial intelligence (AI) technology was already quite the sought-after technology of 2020. Examples included the launch of SoftBank's program to train professionals across Latin America in data science and AI. Not to mention the multiple cases of funding for AI startups like Brazilian Kzas and Colombian VOIQ. However coronavirus (Covid-19) has further illustrated the use of AI in an array of ways.


Autonomous AI, the new necessity - JAXenter

#artificialintelligence

Autonomous IT processes are attractive for their ability to save money and create greater efficiencies. However, as issues with self-driving cars have made clear, automated technologies still need work. Organizations may want to reap the benefits of such technology but are wary of implementing it for fear that it will hinder rather than help. In this light, there are several important elements to consider. SEE ALSO: "Julia is comparable to Python for simple machine learning tasks and better for complex ones" The data deluge continues to hit organizations hard.