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Bucharest was the European capital of robotics for #ERF2019
European Robotics Forum, the most influential meeting of the robotics and AI community, held its 10th anniversary edition in Romania. The event was organized Under the High Patronage of the President of Romania and Under the Patronage of the Romanian Presidency of the Council of the European Union. The most advanced prototypes, high end technology projects, financed under Horizon 2020, were exhibited to be admired and analysed at JW Marriott between 20 and 22 March. Among the robots that were displayed one could find: the famous REEM-C โ the humanoid robot that speaks 9 languages and that costs 1 million euro, QT โ the robot especially created to help children who suffer from autism, Trimbot โ the gardening robot that will help cut the roses and the bushes, as well as other prototypes that take innovation to the next level. Among the exhibitors we could also find Romanian companies developing advanced software solutions for international robotics companies.
Survey on Automated Machine Learning
Zรถller, Marc-Andrรฉ, Huber, Marco F.
Machine learning has become a vital part in many aspects of our daily life. However, building well performing machine learning applications requires highly specialized data scientists and domain experts. Automated machine learning (AutoML) aims to reduce the demand for data scientists by enabling domain experts to automatically build machine learning applications without extensive knowledge of statistics and machine learning. In this survey, we summarize the recent developments in academy and industry regarding AutoML. First, we introduce a holistic problem formulation. Next, approaches for solving various subproblems of AutoML are presented. Finally, we provide an extensive empirical evaluation of the presented approaches on synthetic and real data.
Neural Chinese Named Entity Recognition via CNN-LSTM-CRF and Joint Training with Word Segmentation
Wu, Fangzhao, Liu, Junxin, Wu, Chuhan, Huang, Yongfeng, Xie, Xing
Chinese named entity recognition (CNER) is an important task in Chinese natural language processing field. However, CNER is very challenging since Chinese entity names are highly context-dependent. In addition, Chinese texts lack delimiters to separate words, making it difficult to identify the boundary of entities. Besides, the training data for CNER in many domains is usually insufficient, and annotating enough training data for CNER is very expensive and time-consuming. In this paper, we propose a neural approach for CNER. First, we introduce a CNN-LSTM-CRF neural architecture to capture both local and long-distance contexts for CNER. Second, we propose a unified framework to jointly train CNER and word segmentation models in order to enhance the ability of CNER model in identifying entity boundaries. Third, we introduce an automatic method to generate pseudo labeled samples from existing labeled data which can enrich the training data. Experiments on two benchmark datasets show that our approach can effectively improve the performance of Chinese named entity recognition, especially when training data is insufficient.
Efficient Computation of Expected Hypervolume Improvement Using Box Decomposition Algorithms
Yang, Kaifeng, Emmerich, Michael, Deutz, Andrรฉ, Bรคck, Thomas
In the field of multi-objective optimization algorithms, multi-objective Bayesian Global Optimization (MOBGO) is an important branch, in addition to evolutionary multi-objective optimization algorithms (EMOAs). MOBGO utilizes Gaussian Process Models learned from previous objective function evaluations to decide the next evaluation site by maximizing or minimizing an infill criterion. A common criterion in MOBGO is the Expected Hypervolume Improvement (EHVI), which shows a good performance on a wide range of problems, with respect to exploration and exploitation. However, so far it has been a challenge to calculate exact EHVI values efficiently. In this paper, an efficient algorithm for the computation of the exact EHVI for a generic case is proposed. This efficient algorithm is based on partitioning the integration volume into a set of axis-parallel slices. Theoretically, the upper bound time complexities are improved from previously $O (n^2)$ and $O(n^3)$, for two- and three-objective problems respectively, to $\Theta(n\log n)$, which is asymptotically optimal. This article generalizes the scheme in higher dimensional case by utilizing a new hyperbox decomposition technique, which was proposed by D{\"a}chert et al, EJOR, 2017. It also utilizes a generalization of the multilayered integration scheme that scales linearly in the number of hyperboxes of the decomposition. The speed comparison shows that the proposed algorithm in this paper significantly reduces computation time. Finally, this decomposition technique is applied in the calculation of the Probability of Improvement (PoI).
Deep-IRT: Make Deep Learning Based Knowledge Tracing Explainable Using Item Response Theory
Deep learning based knowledge tracing model has been shown to outperform traditional knowledge tracing model without the need for human-engineered features, yet its parameters and representations have long been criticized for not being explainable. In this paper, we propose Deep-IRT which is a synthesis of the item response theory (IRT) model and a knowledge tracing model that is based on the deep neural network architecture called dynamic key-value memory network (DKVMN) to make deep learning based knowledge tracing explainable. Specifically, we use the DKVMN model to process the student's learning trajectory and estimate the student ability level and the item difficulty level over time. Then, we use the IRT model to estimate the probability that a student will answer an item correctly using the estimated student ability and the item difficulty. Experiments show that the Deep-IRT model retains the performance of the DKVMN model, while it provides a direct psychological interpretation of both students and items.
Synthetic Ground Truth Generation for Evaluating Generative Policy Models
Cunnington, Daniel, White, Graham, de Mel, Geeth
Generative Policy-based Models aim to enable a coalition of systems, be they devices or services to adapt according to contextual changes such as environmental factors, user preferences and different tasks whilst adhering to various constraints and regulations as directed by a managing party or the collective vision of the coalition. Recent developments have proposed new architectures to realize the potential of GPMs but as the complexity of systems and their associated requirements increases, there is an emerging requirement to have scenarios and associated datasets to realistically evaluate GPMs with respect to the properties of the operating environment, be it the future battlespace or an autonomous organization. In order to address this requirement, in this paper, we present a method of applying an agile knowledge representation framework to model requirements, both individualistic and collective that enables synthetic generation of ground truth data such that advanced GPMs can be evaluated robustly in complex environments. We also release conceptual models, annotated datasets, as well as means to extend the data generation approach so that similar datasets can be developed for varying complexities and different situations.
SWALP : Stochastic Weight Averaging in Low-Precision Training
Yang, Guandao, Zhang, Tianyi, Kirichenko, Polina, Bai, Junwen, Wilson, Andrew Gordon, De Sa, Christopher
Low precision operations can provide scalability, memory savings, portability, and energy efficiency. This paper proposes SWALP, an approach to low precision training that averages low-precision SGD iterates with a modified learning rate schedule. SWALP is easy to implement and can match the performance of full-precision SGD even with all numbers quantized down to 8 bits, including the gradient accumulators. Additionally, we show that SWALP converges arbitrarily close to the optimal solution for quadratic objectives, and to a noise ball asymptotically smaller than low precision SGD in strongly convex settings.
Sample Amplification: Increasing Dataset Size even when Learning is Impossible
Axelrod, Brian, Garg, Shivam, Sharan, Vatsal, Valiant, Gregory
Given data drawn from an unknown distribution, $D$, to what extent is it possible to ``amplify'' this dataset and output an even larger set of samples that appear to have been drawn from $D$? We formalize this question as follows: an $(n,m)$ $\text{amplification procedure}$ takes as input $n$ independent draws from an unknown distribution $D$, and outputs a set of $m > n$ ``samples''. An amplification procedure is valid if no algorithm can distinguish the set of $m$ samples produced by the amplifier from a set of $m$ independent draws from $D$, with probability greater than $2/3$. Perhaps surprisingly, in many settings, a valid amplification procedure exists, even when the size of the input dataset, $n$, is significantly less than what would be necessary to learn $D$ to non-trivial accuracy. Specifically we consider two fundamental settings: the case where $D$ is an arbitrary discrete distribution supported on $\le k$ elements, and the case where $D$ is a $d$-dimensional Gaussian with unknown mean, and fixed covariance. In the first case, we show that an $\left(n, n + \Theta(\frac{n}{\sqrt{k}})\right)$ amplifier exists. In particular, given $n=O(\sqrt{k})$ samples from $D$, one can output a set of $m=n+1$ datapoints, whose total variation distance from the distribution of $m$ i.i.d. draws from $D$ is a small constant, despite the fact that one would need quadratically more data, $n=\Theta(k)$, to learn $D$ up to small constant total variation distance. In the Gaussian case, we show that an $\left(n,n+\Theta(\frac{n}{\sqrt{d}} )\right)$ amplifier exists, even though learning the distribution to small constant total variation distance requires $\Theta(d)$ samples. In both the discrete and Gaussian settings, we show that these results are tight, to constant factors. Beyond these results, we formalize a number of curious directions for future research along this vein.
Neural Chinese Word Segmentation with Lexicon and Unlabeled Data via Posterior Regularization
Liu, Junxin, Wu, Fangzhao, Wu, Chuhan, Huang, Yongfeng, Xie, Xing
Existing methods for CWS usually rely on a large In recent years, neural network based methods have been widely number of labeled sentences to train word segmentation models, used for CWS [1, 17, 23, 26]. Most of these methods model CWS as which are expensive and time-consuming to annotate. Luckily, the a sequence labeling problem [22, 30], and utilize neural networks unlabeled data is usually easy to collect and many high-quality to learn the hidden character features [2, 32]. For example, Chen et Chinese lexicons are off-the-shelf, both of which can provide useful al. [2] used LSTM [8] to learn character features by capturing the information for CWS. In this paper, we propose a neural approach global information of sentence. Peng and Dredze [18] proposed to for Chinese word segmentation which can exploit both lexicon use LSTM for character feature learning and CRF [9] for character and unlabeled data. Our approach is based on a variant of posterior label decoding. However, these methods usually rely on a large regularization algorithm, and the unlabeled data and lexicon number of labeled sentences to train word segmentation models, are incorporated into model training as indirect supervision by which are expensive and time-consuming to annotate.
Adversarial Attacks on Deep Neural Networks for Time Series Classification
Fawaz, Hassan Ismail, Forestier, Germain, Weber, Jonathan, Idoumghar, Lhassane, Muller, Pierre-Alain
Time Series Classification (TSC) problems are encountered in many real life data mining tasks ranging from medicine and security to human activity recognition and food safety. With the recent success of deep neural networks in various domains such as computer vision and natural language processing, researchers started adopting these techniques for solving time series data mining problems. However, to the best of our knowledge, no previous work has considered the vulnerability of deep learning models to adversarial time series examples, which could potentially make them unreliable in situations where the decision taken by the classifier is crucial such as in medicine and security. For computer vision problems, such attacks have been shown to be very easy to perform by altering the image and adding an imperceptible amount of noise to trick the network into wrongly classifying the input image. Following this line of work, we propose to leverage existing adversarial attack mechanisms to add a special noise to the input time series in order to decrease the network's confidence when classifying instances at test time. Our results reveal that current state-of-the-art deep learning time series classifiers are vulnerable to adversarial attacks which can have major consequences in multiple domains such as food safety and quality assurance.