Abstract

Advancements in Deep Reinforcement Learning (DRL) have shown significant promise for the development of self directed Unmanned Aerial Vehicles (UAVs). Our research focuses on examining the impact of time-varying noise such as that present in Inertial Measurement Unit (IMU) sensors on the efficacy of DRL-based waypoint navigation and obstacle avoidance in UAVs. Sensor noise affects localization and obstacle detection, and is assumed to follow a Gaussian probability distribution with an unknown non-zero time varying mean and variance. In this study, we consider environment with static obstacles where noise exhibits a time-varying bias, a characteristic commonly associated with IMU sensors. We evaluate the effectiveness of a DRL agent, trained using the Proximal Policy Optimization (PPO) technique, in the presence of such noise.

Abstract

The complex, glinty appearance of detailed normal-mapped surfaces at different scales requires expensive per-pixel Normal Distribution Function computations. Moreover, large light sources further compound this integration and increase the noise in the Monte Carlo renderer. Specialized rendering techniques that explicitly express the underlying normal distribution have been developed to improve performance for glinty surfaces controlled by a fixed material roughness. We present a new method that supports spatially varying roughness based on a neural histogram that computes per-pixel NDFs with arbitrary positions and sizes. Our representation is both memory and compute efficient. Additionally, we fully integrate direct illumination for all light directions in constant time. Our approach decouples roughness and normal distribution, allowing the live editing of the spatially varying roughness of complex normal-mapped objects. We demonstrate that our approach improves on previous work by achieving smaller footprints while offering GPU-friendly computation and compact representation.

Abstract

In this paper, we propose a novel two-step technique for text classification using autoregressive Language Models (LM). In the first step, a set of perplexity and log-likelihood based numeric features are elicited from an LM for a text instance to be classified. Then, in the second step, a classifier based on these features is trained to predict the final label. The classifier used is usually a simple machine learning classifier like Support Vector Machine (SVM) or Logistic Regression (LR) and it is trained using a small set of training examples. We believe, our technique presents a whole new way of exploiting the available training instances, in addition to the existing ways like fine-tuning LMs or in-context learning. Our approach stands out by eliminating the need for parameter updates in LMs, as required in fine-tuning, and does not impose limitations on the number of training examples faced while building prompts for in-context learning. We evaluate our technique across 5 different datasets and compare with multiple competent baselines.

Abstract

To employ Pre-trained Language Models (PLMs) as knowledge containers in niche domains it is important to gauge the knowledge of these PLMs about facts in these domains. It is also an important pre-requisite to know how much enrichment effort is required to make them better. As part of this work, we aim to gauge and enrich small PLMs for knowledge of world geography. Firstly, we develop a moderately sized dataset of masked sentences covering 24 different fact types about world geography to estimate knowledge of PLMs on these facts. We hypothesize that for this niche domain, smaller PLMs may not be well equipped. Secondly, we enrich PLMs with this knowledge through fine-tuning and check if the knowledge in the dataset is infused sufficiently. We further hypothesize that linguistic variability in the manual templates used to embed the knowledge in masked sentences does not affect the knowledge infusion. Finally, we demonstrate the application of PLMs to tourism blog search and Wikidata KB augmentation. In both applications, we aim at showing the effectiveness of using PLMs to achieve competitive performance.

Abstract

The intricate link between brain textbf{Functional Connectivity (FC)} and textbf{Structural Connectivity (SC)} is explored through models performing diffusion on SC to derive FC, using varied methodologies from single to multiple textbf{Graph Diffusion Kernels}. However, existing studies have not correlated diffusion scales with specific brain Regions of Interest (RoIs), limiting the applicability of graph diffusion. We propose a novel approach using textbf{Graph Diffusion Wavelets} to learn the appropriate diffusion scale for each RoI to accurately estimate the SC-FC mapping. Using the open Human Connectome Project (HCP) dataset, we achieve an average textbf{Pearson's correlation} value of 0.833, surpassing the state-of-the-art methods for prediction of FC. It is important to note that the proposed architecture is entirely linear, computationally efficient, and notably demonstrates the textbf{power-law} distribution of diffusion scales. Our results show that the bilateral frontal pole, by virtue of it having large diffusion scale, forms a large community structure. The finding is in line with the current literature on the role of the frontal pole in resting-state networks. Overall, the results underscore the potential of graph diffusion wavelet framework for understanding how the brain structure leads to functional connectivity.

Abstract

The concept of raga in Indian classical music serves as a complex, multifaceted melodic entity that can be approached through various perspectives. Compositions within a raga act as foundational structures, serving as the bedrock for improvisations. Analyzing their textual notations is easier and more objective in comparison with analyzing audio samples. A significant amount of musical insights can be derived from the discrete swara sequences alone. This paper aims to construct an intuitive visualization of raga space, using swara sequences from raga compositions. Notations from public sources are normalized, and their TF-IDF features are projected into a low-dimensional space. This approach allows for qualitative analysis of both Carnatic and Hindustani ragas, mapping them to known raga theory.

Abstract

Edge–cloud coordination offers the chance to mitigate the enormous storage and processing load brought on by a massive increase in traffic at the network’s edge. Though this paradigm has benefits on a large scale, outsourcing the sensitive data from the smart devices deployed in an Internet of Things (IoT) application may lead to privacy leakage. With an attribute-based keyword search (ABKS), the search over ciphertext can be achieved; this reduces the risk of sensitive data explosion. However, ABKS has several issues, like huge computational overhead to perform multi-keyword searches and tracing malicious users. To address these issues and enhance the performance of ABKS, we propose a novel traceable and lightweight attribute-based keyword search technique in an Edge–cloud-assisted IoT, named TL-ABKS, using edge–cloud coordination. With TL-ABKS, it is possible to do effective multi-keyword searches and implement fine-grained access control. Further, TL-ABKS outsources the encryption and decryption computation to edge nodes to enable its usage to resource-limited IoT smart devices. In addition, TL-ABKS achieves tracing user identity who misuse their secret keys. TL-ABKS is secure against modified secret keys, chosen plaintext, and chosen keyword attacks. By comparing the proposed TL-ABKS with the current state-of-the-art schemes, and conducting a theoretical and experimental evaluation of its performance and credibility, TL-ABKS is efficient.

Abstract

Voltage-Controlled Oscillator (VCO) is a crucial component of a Phase-Locked Loop (PLL) system. However, the frequency of a typical Ring-Oscillator-based VCO varies by about 2–3 times across its frequency tuning range and process, voltage and temperature (PVT) conditions. The gain of a Ring-VCO is another crucial parameter that is significantly affected by PVT variations, thereby impacting the stability and loop bandwidth of the PLL. This paper describes a compensation technique to minimize variations in Ring-VCO gain across PVT conditions. A Charge-Pump PLL operating at 4 GHz is implemented in a 28nm CMOS process. The gain of the Ring-VCO varies by ±27% across PVT at 4 GHz. This gain variation of Ring-VCO combined with other PVT-dependent blocks of PLL lead to a deviation of ±60% in Loop Bandwidth and ±21 % in Phase-Margin (PM). Process trimming reduces the VCO gain variation to ±25 %. Subsequently, the temperature compensation technique reduces the VCO gain variation by 3 times to ±8 %, over a temperature range −40∘C to 125∘C . The resulting variations in Loop Bandwidth and Phase-Margin are reduced to ±34%” and ±l5%” respectively.

Abstract

In this work, we introduce an innovative approach to estimate the vital signs of multiple human subjects simultaneously in a non-contact way using a Frequency Modulated Continuous Wave (FMCW) radar-based system. Traditional vital sign monitoring methods often face significant limitations, including subject discomfort with wearable devices, challenges in calibration, and the risk of infection transmission through contact measurement devices. To address these issues, this research is motivated by the need for versatile, non-contact vital monitoring solutions applicable in various critical scenarios. This work also explores the challenges of extending this capability to an arbitrary number of subjects, including hardware and theoretical limitations. Supported by rigorous experimental results and discussions, the paper illustrates the system’s potential to redefine vital sign monitoring. An FPGA-based implementation is also presented as proof of concept for a hardware-based and portable solution, improving upon previous works by offering 2.7x faster execution and 18.4% less Look-Up Table (LUT) utilization, as well as providing over 7400x acceleration compared to its software counterpart.

Abstract

Addressing blockchain's insufficient throughput and scalability is imperative for practical viability. Off-chain approaches, such as state channels (including Hash Time Lock Contract (HTLC), virtual channels), demonstrate enhanced throughput by enabling parallel transaction processing. While virtual channels introduce execution complexity, HTLC suffers from high update delays. Moreover, existing methods face network attacks. We present Sharding-based Hybrid State Channel (SharHSC) to address these issues. Firstly, we introduce a novel off-chain sharding architecture, which partitions proxy nodes into multiple shards. Thus, when the off-chain node count increases, adding shards enhances system throughput. Secondly, each shard establishes a supervisory committee to record latest channel statuses to ensure accurate fund distribution upon channel closure. Thirdly, we combine the strengths of HTLC and virtual channels. In particular, SharHSC constructs a single virtual channel across all the nodes involved in the payment by treating the nodes between payer and payee as an intermediate entity, which utilizes HTLC for fund routing. This realizes both low latency and streamlined complexity. Finally, our work is substantiated by security analysis and experiments. As the node number varies, compared with HTLC and virtual channels, the latency is reduced by 49.32% and 31.82%, and the throughput is increased by 8.93 and 1.89 times.