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Expressivity of Deep Neural Networks

arXiv.org Machine Learning

In this review paper, we give a comprehensive overview of the large variety of approximation results for neural networks. Approximation rates for classical function spaces as well as benefits of deep neural networks over shallow ones for specifically structured function classes are discussed. While the mainbody of existing results is for general feedforward architectures, we also depict approximation results for convolutional, residual and recurrent neural networks.


Innovative And Additive Outlier Robust Kalman Filtering With A Robust Particle Filter

arXiv.org Machine Learning

Anomaly detection is an area of considerable importance and has been subject to increasing attention in recent years. Comprehensive reviews of the area can be found in [1, 2]. The field's growing importance arises from the increasing range of applications to which anomaly detection lends itself: from fraud prevention [1, 2], to fault detection [1, 2], and even the detection of exoplanets [3]. More recently, the emergence of internet of things and the ubiquity of sensors has led to emergence of the online detection of anomalies as an important statistical challenge. Kalman filters [4] provide a convenient framework to detect anomalies within a streaming data context. In particular, they can be updated in a fully online fashion at a fixed computational cost. At each time point, Kalman filters also provide an estimate both for the expectation and variance of the next observation. These can be used to determine whether that observation is anomalous or not. However, the major drawback of Kalman filters is their lack of robustness to outliers: once the filter has encountered an outlier, it will often produce inaccurate predictions for many future time points.


The curious case of developmental BERTology: On sparsity, transfer learning, generalization and the brain

arXiv.org Machine Learning

In this essay, we explore a point of intersection between deep learning and neuroscience, through the lens of large language models, transfer learning and network compression. Just like perceptual and cognitive neurophysiology has inspired effective deep neural network architectures which in turn make a useful model for understanding the brain, here we explore how biological neural development might inspire efficient and robust optimization procedures which in turn serve as a useful model for the maturation and aging of the brain. Hopefully it would inspire the reader in one way or two, or at the very least, kill some boredom during a global pandemic. We are going to touch on the following topics through the lens of large language models: - How do overparameterized deep neural nets generalize? - How does transfer learning help generalization? Before we start, it is prudent to say a few words about the brain metaphor, to clarify this author's position on the issue as it often arises central at debates. The confluence of deep learning and neuroscience arguably took place as early as the conception of artificial neural nets, because artificial neurons abstract characteristic behaviors of biological ones (McCulloch and Pitts, 1943).


Splintering with distributions: A stochastic decoy scheme for private computation

arXiv.org Machine Learning

Performing computations while maintaining privacy is an important problem in todays distributed machine learning solutions. Consider the following two set ups between a client and a server, where in setup i) the client has a public data vector $\mathbf{x}$, the server has a large private database of data vectors $\mathcal{B}$ and the client wants to find the inner products $\langle \mathbf{x,y_k} \rangle, \forall \mathbf{y_k} \in \mathcal{B}$. The client does not want the server to learn $\mathbf{x}$ while the server does not want the client to learn the records in its database. This is in contrast to another setup ii) where the client would like to perform an operation solely on its data, such as computation of a matrix inverse on its data matrix $\mathbf{M}$, but would like to use the superior computing ability of the server to do so without having to leak $\mathbf{M}$ to the server. \par We present a stochastic scheme for splitting the client data into privatized shares that are transmitted to the server in such settings. The server performs the requested operations on these shares instead of on the raw client data at the server. The obtained intermediate results are sent back to the client where they are assembled by the client to obtain the final result.


Deep Learning for Anomaly Detection: A Review

arXiv.org Machine Learning

Anomaly detection has been an active research area for several decades, with early exploration dating back as far as to 1960s [52]. Due to the increasing demand and applications in broad domains, such as risk management, compliance, security, financial surveillance, health and medical risk, and AI safety, anomaly detection plays increasingly important roles, highlighted in various communities including data mining, machine learning, computer vision and statistics. In recent years, deep learning has shown tremendous capabilities in learning expressive representations of complex data such as high-dimensional data, temporal data, spatial data and graph data, pushing the boundaries of different learning tasks.


Paper Digest: ACL 2020 Highlights – Paper Digest

#artificialintelligence

Readers can also choose to read this highlight article on our console, which allows users to filter out papers using keywords and find related papers. Annual Meeting of the Association for Computational Linguistics (ACL) is one of the top natural language processing conferences in the world. In 2020, it is to be held online due to covid-19 pandemic. There were 3,429 paper submissions, of which 778 were accepted. To help the community quickly catch up on the work presented in this conference, Paper Digest Team processed all accepted papers, and generated one highlight sentence (typically the main topic) for each paper.


Global Artificial Intelligence (AI) As a Service Market Forecast 2020-2025 Research Report …

#artificialintelligence

The Global Artificial Intelligence (AI) As a Service Market report gives a detailed overview of the key market drivers, restraints, and trends and analyzes …


Solving Bayesian Network Structure Learning Problem with Integer Linear Programming

arXiv.org Artificial Intelligence

This dissertation investigates integer linear programming (ILP) formulation of Bayesian Network structure learning problem. We review the definition and key properties of Bayesian network and explain score metrics used to measure how well certain Bayesian network structure fits the dataset. We outline the integer linear programming formulation based on the decomposability of score metrics. In order to ensure acyclicity of the structure, we add ``cluster constraints'' developed specifically for Bayesian network, in addition to cycle constraints applicable to directed acyclic graphs in general. Since there would be exponential number of these constraints if we specify them fully, we explain the methods to add them as cutting planes without declaring them all in the initial model. Also, we develop a heuristic algorithm that finds a feasible solution based on the idea of sink node on directed acyclic graphs. We implemented the ILP formulation and cutting planes as a \textsf{Python} package, and present the results of experiments with different settings on reference datasets.


Deep Contextual Embeddings for Address Classification in E-commerce

arXiv.org Machine Learning

E-commerce customers in developing nations like India tend to follow no fixed format while entering shipping addresses. Parsing such addresses is challenging because of a lack of inherent structure or hierarchy. It is imperative to understand the language of addresses, so that shipments can be routed without delays. In this paper, we propose a novel approach towards understanding customer addresses by deriving motivation from recent advances in Natural Language Processing (NLP). We also formulate different pre-processing steps for addresses using a combination of edit distance and phonetic algorithms. Then we approach the task of creating vector representations for addresses using Word2Vec with TF-IDF, Bi-LSTM and BERT based approaches. We compare these approaches with respect to sub-region classification task for North and South Indian cities. Through experiments, we demonstrate the effectiveness of generalized RoBERTa model, pre-trained over a large address corpus for language modelling task. Our proposed RoBERTa model achieves a classification accuracy of around 90% with minimal text preprocessing for sub-region classification task outperforming all other approaches. Once pre-trained, the RoBERTa model can be fine-tuned for various downstream tasks in supply chain like pincode suggestion and geo-coding. The model generalizes well for such tasks even with limited labelled data. To the best of our knowledge, this is the first of its kind research proposing a novel approach of understanding customer addresses in e-commerce domain by pre-training language models and fine-tuning them for different purposes.


Multi-Kernel Fusion for RBF Neural Networks

arXiv.org Machine Learning

A simple yet effective architectural design of radial basis function neural networks (RBFNN) makes them amongst the most popular conventional neural networks. The current generation of radial basis function neural network is equipped with multiple kernels which provide significant performance benefits compared to the previous generation using only a single kernel. In existing multi-kernel RBF algorithms, multi-kernel is formed by the convex combination of the base/primary kernels. In this paper, we propose a novel multi-kernel RBFNN in which every base kernel has its own (local) weight. This novel flexibility in the network provides better performance such as faster convergence rate, better local minima and resilience against stucking in poor local minima. These performance gains are achieved at a competitive computational complexity compared to the contemporary multi-kernel RBF algorithms. The proposed algorithm is thoroughly analysed for performance gain using mathematical and graphical illustrations and also evaluated on three different types of problems namely: (i) pattern classification, (ii) system identification and (iii) function approximation. Empirical results clearly show the superiority of the proposed algorithm compared to the existing state-of-the-art multi-kernel approaches.