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LS-SVR as a Bayesian RBF network
Mesquita, Diego P. P., Freitas, Luis A., Gomes, João P. P., Mattos, César L. C.
Statistical learning theory has been studied for general function estimation from data since the late 1960's [22]. However, it was only widely adopted in practice after the introduction of the learning algorithms known as Support Vector Machines (SVMs) [23]. Using the so-called kernel trick, which replaces dot products between features and model parameters by evaluations of a kernel function, SVMs can learn nonlinear relations from training patterns by solving a convex optimization problem [16]. An important variant of the SVM is the Least Squares Support Vector Machine (LS-SVM) [20], which is obtained by making all data points supportvectors. LS-SVM avoids the constrained quadratic optimization step of standard SVMs by replacing the training procedure with one that reduces to solving a system of linear equations, which can be performed via ordinary least squares. The first SVM formulation was derived for classification tasks, but it has been readily adapted to tackle regression problems, being usually named Support Vector Regression (SVR) [6]. Similarly, the regression counterpart of LS-SVM is the LS-SVR [20]. 1
High-Performance Support Vector Machines and Its Applications
He, Taiping, Wang, Tao, Abbey, Ralph, Griffin, Joshua
The support vector machines (SVM) algorithm is a popular classification technique in data mining and machine learning. In this paper, we propose a distributed SVM algorithm and demonstrate its use in a number of applications. The algorithm is named high-performance support vector machines (HPSVM). The major contribution of HPSVM is two-fold. First, HPSVM provides a new way to distribute computations to the machines in the cloud without shuffling the data. Second, HPSVM minimizes the inter-machine communications in order to maximize the performance. We apply HPSVM to some real-world classification problems and compare it with the state-of-the-art SVM technique implemented in R on several public data sets. HPSVM achieves similar or better results.
Introducing Graph Smoothness Loss for Training Deep Learning Architectures
Bontonou, Myriam, Lassance, Carlos, Hacene, Ghouthi Boukli, Gripon, Vincent, Tang, Jian, Ortega, Antonio
We introduce a novel loss function for training deep learning architectures to perform classification. It consists in minimizing the smoothness of label signals on similarity graphs built at the output of the architecture. Equivalently, it can be seen as maximizing the distances between the network function images of training inputs from distinct classes. As such, only distances between pairs of examples in distinct classes are taken into account in the process, and the training does not prevent inputs from the same class to be mapped to distant locations in the output domain. We show that this loss leads to similar performance in classification as architectures trained using the classical cross-entropy, while offering interesting degrees of freedom and properties. We also demonstrate the interest of the proposed loss to increase robustness of trained architectures to deviations of the inputs.
Surface Type Classification for Autonomous Robot Indoor Navigation
Lomio, Francesco, Skenderi, Erjon, Mohamadi, Damoon, Collin, Jussi, Ghabcheloo, Reza, Huttunen, Heikki
Abstract--In this work we describe the preparation of a time series dataset of inertial measurements for determining the surface type under a wheeled robot. The data consists of over 7600 labeled time series samples, with the corresponding surface type annotation. This data was used in two public competitions with over 1500 participant in total. Additionally, we describe the performance of state-of-art deep learning models for time series classification, as well as propose a baseline model based on an ensemble of machine learning methods. The baseline achieves an accuracy of over 68% with our nine-category dataset.
Model Comparison for Semantic Grouping
Vargas, Francisco, Brestnichki, Kamen, Hammerla, Nils
We introduce a probabilistic framework for quantifying the semantic similarity between two groups of embeddings. We formulate the task of semantic similarity as a model comparison task in which we contrast a generative model which jointly models two sentences versus one that does not. We illustrate how this framework can be used for the Semantic Textual Similarity tasks using clear assumptions about how the embeddings of words are generated. We apply model comparison that utilises information criteria to address some of the shortcomings of Bayesian model comparison, whilst still penalising model complexity. We achieve competitive results by applying the proposed framework with an appropriate choice of likelihood on the STS datasets.
Detecting Adversarial Examples through Nonlinear Dimensionality Reduction
Crecchi, Francesco, Bacciu, Davide, Biggio, Battista
Deep neural networks are vulnerable to adversarial examples, i.e., carefully-perturbed inputs aimed to mislead classification. This work proposes a detection method based on combining non-linear dimensionality reduction and density estimation techniques. Our empirical findings show that the proposed approach is able to effectively detect adversarial examples crafted by non-adaptive attackers, i.e., not specifically tuned to bypass the detection method. Given our promising results, we plan to extend our analysis to adaptive attackers in future work.
Free Gap Information from the Differentially Private Sparse Vector and Noisy Max Mechanisms
Ding, Zeyu, Wang, Yuxin, Zhang, Danfeng, Kifer, Daniel
Noisy Max and Sparse Vector are selection algorithms for differential privacy and serve as building blocks for more complex algorithms. In this paper we show that both algorithms can release additional information for free (i.e., at no additional privacy cost). Noisy Max is used to return the approximate maximizer among a set of queries. We show that it can also release for free the noisy gap between the approximate maximizer and runner-up. Sparse Vector is used to return a set of queries that are approximately larger than a fixed threshold. We show that it can adaptively control its privacy budget (use less budget for queries that are likely to be much larger than the threshold) and simultaneously release for free a noisy gap between the selected queries and the threshold. It has long been suspected that Sparse Vector can release additional information, but prior attempts had incorrect proofs. Our version is proved using randomness alignment, a proof template framework borrowed from the program verification literature. We show how the free extra information in both mechanisms can be used to improve the utility of differentially private algorithms.
SysML: The New Frontier of Machine Learning Systems
Ratner, Alexander, Alistarh, Dan, Alonso, Gustavo, Andersen, David G., Bailis, Peter, Bird, Sarah, Carlini, Nicholas, Catanzaro, Bryan, Chayes, Jennifer, Chung, Eric, Dally, Bill, Dean, Jeff, Dhillon, Inderjit S., Dimakis, Alexandros, Dubey, Pradeep, Elkan, Charles, Fursin, Grigori, Ganger, Gregory R., Getoor, Lise, Gibbons, Phillip B., Gibson, Garth A., Gonzalez, Joseph E., Gottschlich, Justin, Han, Song, Hazelwood, Kim, Huang, Furong, Jaggi, Martin, Jamieson, Kevin, Jordan, Michael I., Joshi, Gauri, Khalaf, Rania, Knight, Jason, Konečný, Jakub, Kraska, Tim, Kumar, Arun, Kyrillidis, Anastasios, Lakshmiratan, Aparna, Li, Jing, Madden, Samuel, McMahan, H. Brendan, Meijer, Erik, Mitliagkas, Ioannis, Monga, Rajat, Murray, Derek, Olukotun, Kunle, Papailiopoulos, Dimitris, Pekhimenko, Gennady, Rekatsinas, Theodoros, Rostamizadeh, Afshin, Ré, Christopher, De Sa, Christopher, Sedghi, Hanie, Sen, Siddhartha, Smith, Virginia, Smola, Alex, Song, Dawn, Sparks, Evan, Stoica, Ion, Sze, Vivienne, Udell, Madeleine, Vanschoren, Joaquin, Venkataraman, Shivaram, Vinayak, Rashmi, Weimer, Markus, Wilson, Andrew Gordon, Xing, Eric, Zaharia, Matei, Zhang, Ce, Talwalkar, Ameet
Machine learning (ML) techniques are enjoying rapidly increasing adoption. However, designing and implementing the systems that support ML models in real-world deployments remains a significant obstacle, in large part due to the radically different development and deployment profile of modern ML methods, and the range of practical concerns that come with broader adoption. We propose to foster a new systems machine learning research community at the intersection of the traditional systems and ML communities, focused on topics such as hardware systems for ML, software systems for ML, and ML optimized for metrics beyond predictive accuracy. To do this, we describe a new conference, SysML, that explicitly targets research at the intersection of systems and machine learning with a program committee split evenly between experts in systems and ML, and an explicit focus on topics at the intersection of the two.
Regularity Normalization: Constraining Implicit Space with Minimum Description Length
Inspired by the adaptation phenomenon of biological neuronal firing, we propose regularity normalization: a reparameterization of the activation in the neural network that take into account the statistical regularity in the implicit space. By considering the neural network optimization process as a model selection problem, the implicit space is constrained by the normalizing factor, the minimum description length of the optimal universal code. We introduce an incremental version of computing this universal code as normalized maximum likelihood and demonstrated its flexibility to include data prior such as top-down attention and other oracle information and its compatibility to be incorporated into batch normalization and layer normalization. The preliminary results showed that the proposed method outperforms existing normalization methods in tackling the limited and imbalanced data from a non-stationary distribution benchmarked on computer vision tasks. As an unsupervised attention mechanism given input data, this biologically plausible normalization has the potential to deal with other complicated real-world scenarios as well as reinforcement learning setting where the rewards are sparse and non-uniform. Further research is proposed to discover these scenarios and explore the behaviors among different variants.
TimbreTron: A WaveNet(CycleGAN(CQT(Audio))) Pipeline for Musical Timbre Transfer
Huang, Sicong, Li, Qiyang, Anil, Cem, Bao, Xuchan, Oore, Sageev, Grosse, Roger B.
In this work, we address the problem of musical timbre transfer, where the goal is to manipulate the timbre of a sound sample from one instrument to match another instrument while preserving other musical content, such as pitch, rhythm, and loudness. In principle, one could apply image-based style transfer techniques to a time-frequency representation of an audio signal, but this depends on having a representation that allows independent manipulation of timbre as well as high-quality waveform generation. We introduce TimbreTron, a method for musical timbre transfer which applies "image" domain style transfer to a time-frequency representation of the audio signal, and then produces a high-quality waveform using a conditional WaveNet synthesizer. We show that the Constant Q Transform (CQT) representation is particularly well-suited to convolutional architectures due to its approximate pitch equivariance. Based on human perceptual evaluations, we confirmed that TimbreTron recognizably transferred the timbre while otherwise preserving the musical content, for both monophonic and polyphonic samples.