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Why Interpretability in Machine Learning? An Answer Using Distributed Detection and Data Fusion Theory
Varshney, Kush R., Khanduri, Prashant, Sharma, Pranay, Zhang, Shan, Varshney, Pramod K.
As artificial intelligence is increasingly affecting all parts of society and life, there is growing recognition that human interpretability of machine learning models is important. It is often argued that accuracy or other similar generalization performance metrics must be sacrificed in order to gain interpretability. Such arguments, however, fail to acknowledge that the overall decision-making system is composed of two entities: the learned model and a human who fuses together model outputs with his or her own information. As such, the relevant performance criteria should be for the entire system, not just for the machine learning component. In this work, we characterize the performance of such two-node tandem data fusion systems using the theory of distributed detection. In doing so, we work in the population setting and model interpretable learned models as multi-level quantizers. We prove that under our abstraction, the overall system of a human with an interpretable classifier outperforms one with a black box classifier.
Learning dynamical systems with particle stochastic approximation EM
Svensson, Andreas, Lindsten, Fredrik
Learning of dynamical systems, or state-space models, is central to many machine learning problems, such as reinforcement learning, sequence modeling, and autonomous systems. Furthermore, state-space models are at the core of recent model developments within the machine learning area, such as Gaussian process state-space models (Frigola et al. 2014a; Mattos et al. 2016; etc.), infinite factorial dynamical models (Gael et al., 2009; Valera et al., 2015), and stochastic recurrent neural networks (Fraccaro et al., 2016, for example). A strategy to learn state-space models, independently suggested by Digalakis et al. (1993) and Ghahramani and Hinton (1996), is the use of the Expectation Maximization (EM, Dempster et al. 1977) method. Even though originally proposed only for maximum likelihood estimation of linear models with Gaussian noise, the strategy can be generalized to the more challenging nonlinear and non-Gaussian cases, as well as the empirical Bayes setting. Many contributions have been made during the last decade, and this paper takes another step along the path towards a more computationally efficient method with a solid theoretical ground for learning of nonlinear dynamical systems.
Correlated pseudo-marginal Metropolis-Hastings using quasi-Newton proposals
Dahlin, Johan, Wills, Adrian, Ninness, Brett
Pseudo-marginal Metropolis-Hastings (pmMH) is a versatile algorithm for sampling from target distributions which are not easy to evaluate point-wise. However, pmMH requires good proposal distributions to sample efficiently from the target, which can be problematic to construct in practice. This is especially a problem for high-dimensional targets when the standard random-walk proposal is inefficient. We extend pmMH to allow for constructing the proposal based on information from multiple past iterations. As a consequence, quasi-Newton (qN) methods can be employed to form proposals which utilize gradient information to guide the Markov chain to areas of high probability and to construct approximations of the local curvature to scale step sizes. The proposed method is demonstrated on several problems which indicate that qN proposals can perform better than other common Hessian-based proposals.
Mimic and Classify : A meta-algorithm for Conditional Independence Testing
Sen, Rajat, Shanmugam, Karthikeyan, Asnani, Himanshu, Rahimzamani, Arman, Kannan, Sreeram
Given independent samples generated from the joint distribution $p(\mathbf{x},\mathbf{y},\mathbf{z})$, we study the problem of Conditional Independence (CI-Testing), i.e., whether the joint equals the CI distribution $p^{CI}(\mathbf{x},\mathbf{y},\mathbf{z})= p(\mathbf{z}) p(\mathbf{y}|\mathbf{z})p(\mathbf{x}|\mathbf{z})$ or not. We cast this problem under the purview of the proposed, provable meta-algorithm, "Mimic and Classify", which is realized in two-steps: (a) Mimic the CI distribution close enough to recover the support, and (b) Classify to distinguish the joint and the CI distribution. Thus, as long as we have a good generative model and a good classifier, we potentially have a sound CI Tester. With this modular paradigm, CI Testing becomes amiable to be handled by state-of-the-art, both generative and classification methods from the modern advances in Deep Learning, which in general can handle issues related to curse of dimensionality and operation in small sample regime. We show intensive numerical experiments on synthetic and real datasets where new mimic methods such conditional GANs, Regression with Neural Nets, outperform the current best CI Testing performance in the literature. Our theoretical results provide analysis on the estimation of null distribution as well as allow for general measures, i.e., when either some of the random variables are discrete and some are continuous or when one or more of them are discrete-continuous mixtures.
EmbNum: Semantic labeling for numerical values with deep metric learning
Nguyen, Phuc, Nguyen, Khai, Ichise, Ryutaro, Takeda, Hideaki
Semantic labeling is a task of matching unknown data source to labeled data sources. The semantic labels could be properties, classes in knowledge bases or labeled data are manually annotated by domain experts. In this paper, we present EmbNum, a novel approach to match numerical columns from different table data sources. We use a representation network architecture consisting of triplet network and convolutional neural network to learn a mapping function from numerical columns to a transformed space. In this space, the Euclidean distance can be used to measure "semantic similarity" of two columns. Our experiments on City-Data and Open-Data demonstrate that EmbNum achieves considerable improvements in comparison with the state-of-the-art methods on effectiveness and efficiency.
Diversified Late Acceptance Search
Namazi, Majid, Sanderson, Conrad, Newton, M. A. Hakim, Polash, M. M. A., Sattar, Abdul
The well-known Late Acceptance Hill Climbing (LAHC) search aims to overcome the main downside of traditional Hill Climbing (HC) search, which is often quickly trapped in a local optimum due to strictly accepting only non-worsening moves within each iteration. In contrast, LAHC also accepts worsening moves, by keeping a circular array of fitness values of previously visited solutions and comparing the fitness values of candidate solutions against the least recent element in the array. While the straightforward strategy followed by LAHC has proven effective, there are nevertheless situations where LAHC can unfortunately behave in a similar manner to HC, even when using a large fitness array. For example, when the same fitness value is stored many times in the array, particularly when a new local optimum is found. To address this shortcoming, we propose to improve both the diversity of the accepted solutions and the diversity of values in the array through new acceptance and replacement strategies. The proposed Diversified Late Acceptance Search approach is shown to outperform the current state-of-the-art LAHC method on benchmark sets of Travelling Salesman Problem and Quadratic Assignment Problem instances.
The Emotional Voices Database: Towards Controlling the Emotion Dimension in Voice Generation Systems
Adigwe, Adaeze, Tits, Noรฉ, Haddad, Kevin El, Ostadabbas, Sarah, Dutoit, Thierry
In this paper, we present a database of emotional speech intended to be open-sourced and used for synthesis and generation purpose. It contains data for male and female actors in English and a male actor in French. The database covers 5 emotion classes so it could be suitable to build synthesis and voice transformation systems with the potential to control the emotional dimension in a continuous way. We show the data's efficiency by building a simple MLP system converting neutral to angry speech style and evaluate it via a CMOS perception test. Even though the system is a very simple one, the test show the efficiency of the data which is promising for future work.
AI Weekly: The growing importance of clear AI ethics policies
A little over a week after the fervor surrounding Google's involvement in the Department of Defense's Project Maven, an autonomous drone program, showed signs of abating, another machine learning controversy returned to the headlines: local law enforcement deploying Amazon's Rekognition, a computer vision service with facial recognition capabilities. In a letter addressed to Amazon CEO Jeff Bezos, 19 groups of shareholders expressed concerns that Rekognition's facial recognition capabilities will be misused in ways that "violate [the] civil and human rights" of "people of color, immigrants, and civil society organizations." And they said that it set the stage for sales of the software to foreign governments and authoritarian regimes. Amazon, for its part, said in a statement that it will "suspend โฆ customer's right to use โฆ services [like Rekognition]" if it determines those services are being "abused." It has so far declined, however, to define the bright-line rules that would trigger a suspension.
Human IQ and Artificial Intelligence Can Work Together, Business Professor Says
With the advent of new technologies, experts now say the definition of intelligence is changing. Smart people are not just individuals capable of solving complicated problems on their own, but also those who understand the way artificial intelligence, or AI, can best serve them. Simply put, understanding technology is essential. Yet technology and artificial intelligence often scare people who get tangled in complicated explanations of what AI is and how it works. Two professors, Nick Polson from the University of Chicago Booth School of Business and James Scott from the University of Texas at Austin, tried to put a face on the technology by writing a book that illustrates the beginning of AI through several examples of historical figures and other individuals who developed algorithms for humanity's different problems.