Abstract

Maintaining the river water quality has become more prominent these days due to excess pollutants from various sources like industries and domestic sewage discharge. The assessment of river water quality is a significant task for the management and sustainability of the riverine health system for future generations. This study evaluates the water quality of the Bhadra river stretch in India using the water quality index and qual2k model. The water quality index (WQI) is estimated using Weighted Average Water Quality Index (WAWQI) method and water quality indicators like Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO), Electrical Conductivity (Ec), Nitrate (NO3), pH, and Temperature are simulated using Qual2k model. The Qual2k model was calibrated and validated for a period of 91-months (April 2006 to October 2013). The estimated WQI values range from 92.35 to 112, and the quality classification ranges from very poor to unfit for consumption. It was observed that the quality status of the river water was very poor in upstream and downstream segments, while unfit for consumption in the middle segment indicating access to industrial and anthropogenic activities. To conserve river water from pollution, strict laws and regulations must be implemented to improve health and preserve water resources for future generations.

Abstract

After one learns to program in miniKanren, it is natural to want to understand how it is implemented. However, there is no resource to learn how to implement miniKanren with constraints such as =/=, symbolo, numbero, and absento. Furthermore, these are used to implement a wide class of interesting programs such as relational interpreters and relational type inferencers, making the need for such a resource all the more felt. This paper aims to be that resource. Additional Key Words and Phrases: miniKanren implementation, Racket, relational programming

Abstract

Homeostasis represents the idea that a feature may remain invariant despite changes in some external parameters. We establish a connection between homeostasis and injectivity for reaction network models. In particular, we show that a reaction network cannot exhibit homeostasis if a modified version of the network (which we call homeostasis-associated network) is injective. We provide examples of reaction networks which can or cannot exhibit homeostasis by analyzing the injectivity of their homeostasis-associated networks.

Abstract

Autocatalytic systems called hypercycles are very often incorporated in "origin of life" models. We investigate the dynamics of certain related models called bimolecular autocatalytic systems. In particular, we consider the dynamics corresponding to the relative populations in these networks, and show that it can be analyzed using well-chosen autonomous polynomial dynamical systems. Moreover, we use results from reaction network theory to prove persistence and permanence of several families of bimolecular autocatalytic systems called autocatalytic recombination systems. Keywords: Autocatalytic recombination networks; Origin of life; Permanence; Persistence. Copyright © 2022 Elsevier Inc. All rights reserved.

Abstract

Quadrotors are becoming more and more essen- tial for applications such as payload delivery, inspection and search-and-rescue. Such operations pose considerable control challenges, especially when various (a priori unbounded) state- dependent unknown dynamics arises from payload variations, aerodynamic effects and from reaction forces while operating close to the ground or in a confined space. However, existing adaptive control strategies for quadrotors cannot handle un- known state-dependent uncertainties. We address such unsolved control challenge in this work via a novel adaptive method for artificial time delay control, where unknown dynamics is robustly compensated by using input and state measurements collected at immediate past time instant (i.e., artificially delayed). Closed-loop stability is established via Lyapunov theory. The effectiveness of this controller is validated using experimental results

Abstract

This work introduces a new single-stage adaptive controller for Euler-Lagrange systems with nonholonomic con- straints. The proposed mechanism provides a simpler design philosophy compared to double-stage mechanisms (that ad- dress kinematics and dynamics in two steps), while achieving analogous stability properties, i.e. stability of both original and internal states. Meanwhile, we do not require direct access to the internal states as required in state-of-the-art single-stage mechanisms. The proposed approach is studied via Lyapunov analysis, validated numerically on wheeled mobile robot dy- namics and compared to a standard double-stage approach

Abstract

The high maneuverability of fixed-wing un- manned aerial vehicles (UAVs) exposes these systems to several dynamical and parametric uncertainties, severely affecting the fidelity of modeling and causing limited guid- ance autonomy. This article shows enhanced autonomy via adaptation mechanisms embedded in the guidance law: a vector-field method is proposed that does not require a priori knowledge of the UAV course time constant, cou- pling effects, and wind amplitude/direction. Stability and performance are assessed using the Lyapunov theory. The method is tested on software-in-the loop and hardware-in- the-loop UAV platforms, showing that the proposed guid- ance law outperforms state-of-the-art guidance controllers and standard vector-field approaches in the presence of significant uncertainty. Index Terms—Adaptive guidance, adaptive sliding-mode control, fixed-wing unmanned aerial vehicles (UAV), un- known dynamics, vector field (VF).

Abstract

In this work, we describe an end-to-end deep learning architecture for Heart Murmur Detection from Phonocardiogram(PCG) recordings as part of The George B. Moody PhysioNet Challenge 2022. Our team, “Team IIITH” received a weighted accuracy score of 0.708 (ranked 19th out of 40 teams) and Challenge cost of 13264 (ranked 22nd out of 39 teams) on the official hidden test set. In our approach, the PCG recordings are first downsampled to 1000 Hz before being passed through a Butterworth’s low and high pass filter to remove baseline wanders and high-frequency noise present in the recordings. The PCG recordings are then broken down into 10-second segments and normalized to bring all trainable samples to the same size. To extract embeddings more efficiently, we built a custom 1-dimensional Residual Network (ResNet) where the 10-second inputs are passed through variable-sized kernel ResNets in parallel, before being concatenated and passed through the next ResNet layer to account for different length dependencies across the PCG signal. The output of this custom ResNet is then fed to a 2-layer feed-forward network for final classification. Cross-Entropy Loss with class weights was employed to account for class imbalance. Our approach obtained a 5-fold Cross-Validation weighted accuracy score of 0.71 and challenge cost score of 12067 on the training set.

Abstract

Neuroimaging techniques such as fMRI record brain activation while participants experience a stimulus. The concreteness of concepts defines how well our brain is able to imagine them. We hypothesise that brain activation would be distinctly different when participants view stimuli corresponding to concrete words versus abstract words. Specifically, we expect primary sensory areas to engage more in the former. To study this, we used a multi-view dataset with each concept being displayed as a picture, as a word in a sentence and also as a wordcloud [1]. We investigate how well a machine learning-based decoder trained on concrete concepts can decode both concrete and abstract concepts and vice versa for the model trained on abstract concepts. We find that a model trained on stimuli related to concrete concepts yields better accuracy than the model trained on abstract concepts. We also explore the contribution of voxels from different brain regions in this decoding process. Analysis of the contribution of different brain networks reveals exciting cognitive insights.

Abstract

We identify a large family of abelian codes that achieve the capacity of the binary erasure channel (BEC) under bit-MAP decoding. The codes in this family have rich automorphism groups, their lengths are odd integers, and they can asymptotically (in the block length) achieve any code rate. This family contains codes of prime power block lengths that were originally identified by Berman (1967) and later inves- tigated by Blackmore and Norton (2001), and also contains their generalization to any odd block length. We use Rajan and Siddiqi’s (1992) characterization of abelian codes using discrete Fourier transform (DFT) to identify our code family and study their automorphism groups. We then use a result of Kumar, Calderbank and Pfister (2016) that relates the automorphism group of a code to its performance in the BEC to show that this code family achieves BEC capacity. The full version of this paper, including the proofs of all claims and simulation results, is available online