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How IIT Guwahati Leads Cutting-Edge Research In AI & Data Science

#artificialintelligence

The Indian Institute of Technology, Guwahati (IITG), established in 1994, has a vision: "To be recognised globally for excellence in education, research and innovation, and nurture future leaders, to serve the society at large." Analytics India Magazine got in touch with three IITG professors, namely Ratnajit Bhattacharjee, Siddhartha Pratim Chakrabarty, and Ashok Singh Sairam, to understand IITG's contributions to the burgeoning field of AI and Data Science in India. Professors: IITG faculty members are currently engaged in research activities in different topics in the field of AI and Machine Learning (ML), particularly their applications. Recently, IITG, in collaboration with several other leading institutes and organisations, has submitted a proposal for a Centre of Excellence (CoE) on the topic of Deep Learning for geo-hazards prediction to the Science and Engineering Research Board (SERB) for possible funding. If this CoE gets established, there will be cutting edge research activities in the application of Deep Learning and the emerging Internet of Things (IoT) technologies.


Impulse Response -- data augmentation for audio deep learning

#artificialintelligence

In recent years, deep learning for audio has come a long way with models beating traditional signal processing techniques in many of the downstream tasks. However, many such solutions are trained on "homogeneous" datasets -- datasets where there is little variability in the recording conditions (noise, accent, language, etc.). Many such models do not perform very well (especially audio conversion/synthesis tasks) when used on real world "audio events" which can contain short burst, environment noises, background speakers, poor microphones, etc. While there are many techniques address them, here we concern ourselves with data augmentation with impulse responses, which at times can be really powerful since it simulates different recording environments. An impulse response of a dynamic system describes how it reacts when presented with a brief input signal called the impulse.


How to Select an Initial Model for your Data Science Problem - KDnuggets

#artificialintelligence

This post is meant for new and or aspiring data scientists trying to decide what model to use for a problem. This post will not be going over data wrangling. Which hopefully, you know, is the majority of the work a data scientist does. I'm assuming you have some data ready, and you want to see how you can make some predictions. There are many models to choose from with seemingly endless variants.


Evolutionary Ensemble Learning for Multivariate Time Series Prediction

arXiv.org Artificial Intelligence

Multivariate time series (MTS) prediction plays a key role in many fields such as finance, energy and transport, where each individual time series corresponds to the data collected from a certain data source, so-called channel. A typical pipeline of building an MTS prediction model (PM) consists of selecting a subset of channels among all available ones, extracting features from the selected channels, and building a PM based on the extracted features, where each component involves certain optimization tasks, i.e., selection of channels, feature extraction (FE) methods, and PMs as well as configuration of the selected FE method and PM. Accordingly, pursuing the best prediction performance corresponds to optimizing the pipeline by solving all of its involved optimization problems. This is a non-trivial task due to the vastness of the solution space. Different from most of the existing works which target at optimizing certain components of the pipeline, we propose a novel evolutionary ensemble learning framework to optimize the entire pipeline in a holistic manner. In this framework, a specific pipeline is encoded as a candidate solution and a multi-objective evolutionary algorithm is applied under different population sizes to produce multiple Pareto optimal sets (POSs). Finally, selective ensemble learning is designed to choose the optimal subset of solutions from the POSs and combine them to yield final prediction by using greedy sequential selection and least square methods. We implement the proposed framework and evaluate our implementation on two real-world applications, i.e., electricity consumption prediction and air quality prediction. The performance comparison with state-of-the-art techniques demonstrates the superiority of the proposed approach.


Document-level Relation Extraction as Semantic Segmentation

arXiv.org Artificial Intelligence

Document-level relation extraction aims to extract relations among multiple entity pairs from a document. Previously proposed graph-based or transformer-based models utilize the entities independently, regardless of global information among relational triples. This paper approaches the problem by predicting an entity-level relation matrix to capture local and global information, parallel to the semantic segmentation task in computer vision. Herein, we propose a Document U-shaped Network for document-level relation extraction. Specifically, we leverage an encoder module to capture the context information of entities and a U-shaped segmentation module over the image-style feature map to capture global interdependency among triples. Experimental results show that our approach can obtain state-of-the-art performance on three benchmark datasets DocRED, CDR, and GDA.


Electroencephalogram Signal Processing with Independent Component Analysis and Cognitive Stress Classification using Convolutional Neural Networks

arXiv.org Artificial Intelligence

Electroencephalogram (EEG) is the recording which is the result due to the activity of bio-electrical signals that is acquired from electrodes placed on the scalp. In Electroencephalogram signal(EEG) recordings, the signals obtained are contaminated predominantly by the Electrooculogram(EOG) signal. Since this artifact has higher magnitude compared to EEG signals, these noise signals have to be removed in order to have a better understanding regarding the functioning of a human brain for applications such as medical diagnosis. This paper proposes an idea of using Independent Component Analysis(ICA) along with cross-correlation to de-noise EEG signal. This is done by selecting the component based on the cross-correlation coefficient with a threshold value and reducing its effect instead of zeroing it out completely, thus reducing the information loss. The results of the recorded data show that this algorithm can eliminate the EOG signal artifact with little loss in EEG data. The denoising is verified by an increase in SNR value and the decrease in cross-correlation coefficient value. The denoised signals are used to train an Artificial Neural Network(ANN) which would examine the features of the input EEG signal and predict the stress levels of the individual.


Long-term, Short-term and Sudden Event: Trading Volume Movement Prediction with Graph-based Multi-view Modeling

arXiv.org Artificial Intelligence

Trading volume movement prediction is the key in a variety of financial applications. Despite its importance, there is few research on this topic because of its requirement for comprehensive understanding of information from different sources. For instance, the relation between multiple stocks, recent transaction data and suddenly released events are all essential for understanding trading market. However, most of the previous methods only take the fluctuation information of the past few weeks into consideration, thus yielding poor performance. To handle this issue, we propose a graphbased approach that can incorporate multi-view information, i.e., long-term stock trend, short-term fluctuation and sudden events information jointly into a temporal heterogeneous graph. Besides, our method is equipped with deep canonical analysis to highlight the correlations between different perspectives of fluctuation for better prediction. Experiment results show that our method outperforms strong baselines by a large margin.


New Trends in Quantum Machine Learning

arXiv.org Machine Learning

Here we will give a perspective on new possible interplays between Machine Learning and Quantum Physics, including also practical cases and applications. We will explore the ways in which machine learning could benefit from new quantum technologies and algorithms to find new ways to speed up their computations by breakthroughs in physical hardware, as well as to improve existing models or devise new learning schemes in the quantum domain. Moreover, there are lots of experiments in quantum physics that do generate incredible amounts of data and machine learning would be a great tool to analyze those and make predictions, or even control the experiment itself. On top of that, data visualization techniques and other schemes borrowed from machine learning can be of great use to theoreticians to have better intuition on the structure of complex manifolds or to make predictions on theoretical models. This new research field, named as Quantum Machine Learning, is very rapidly growing since it is expected to provide huge advantages over its classical counterpart and deeper investigations are timely needed since they can be already tested on the already commercially available quantum machines.


An Efficient Mini-batch Method via Partial Transportation

arXiv.org Machine Learning

Mini-batch optimal transport (m-OT) has been widely used recently to deal with the memory issue of OT in large-scale applications. Despite their practicality, m-OT suffers from misspecified mappings, namely, mappings that are optimal on the mini-batch level but do not exist in the optimal transportation plan between the original measures. To address the misspecified mappings issue, we propose a novel mini-batch method by using partial optimal transport (POT) between mini-batch empirical measures, which we refer to as mini-batch partial optimal transport (m-POT). Leveraging the insight from the partial transportation, we explain the source of misspecified mappings from the m-OT and motivate why limiting the amount of transported masses among mini-batches via POT can alleviate the incorrect mappings. Finally, we carry out extensive experiments on various applications to compare m-POT with m-OT and recently proposed mini-batch method, mini-batch unbalanced optimal transport (m-UOT). We observe that m-POT is better than m-OT deep domain adaptation applications while having comparable performance with m-UOT. On other applications, such as deep generative model, gradient flow, and color transfer, m-POT yields more favorable performance than both m-OT and m-UOT.


DTWSSE: Data Augmentation with a Siamese Encoder for Time Series

arXiv.org Artificial Intelligence

Access to labeled time series data is often limited in the real world, which constrains the performance of deep learning models in the field of time series analysis. Data augmentation is an effective way to solve the problem of small sample size and imbalance in time series datasets. The two key factors of data augmentation are the distance metric and the choice of interpolation method. SMOTE does not perform well on time series data because it uses a Euclidean distance metric and interpolates directly on the object. Therefore, we propose a DTW-based synthetic minority oversampling technique using siamese encoder for interpolation named DTWSSE. In order to reasonably measure the distance of the time series, DTW, which has been verified to be an effective method forts, is employed as the distance metric. To adapt the DTW metric, we use an autoencoder trained in an unsupervised self-training manner for interpolation. The encoder is a Siamese Neural Network for mapping the time series data from the DTW hidden space to the Euclidean deep feature space, and the decoder is used to map the deep feature space back to the DTW hidden space. We validate the proposed methods on a number of different balanced or unbalanced time series datasets. Experimental results show that the proposed method can lead to better performance of the downstream deep learning model.