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Pavia Bera

Publications and source records attributed to Pavia Bera.

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Distributed Hierarchical Temporal Memory with Shared Associative Memory for Cross-Entity Preemptive Warning

Anomaly detection in multivariate time series remains a critical challenge in large-scale distributed systems, where related entities may exhibit transferable precursor behavior prior to anomaly onset. Existing methods typically operate independently on each data stream and therefore remain fundamentally reactive. To address this limitation, we introduce Distributed Hierarchical Temporal Memory (D-HTM), a neuromorphic framework that enables cross-entity preemptive warning through a Shared Associative Memory (SAM). D-HTM combines a Spatial Pooler (SP) that projects observations into a common Sparse Distributed Representation (SDR) space, Temporal Memory (TM) modules that learn entity-specific dynamics online, and a Shared Associative Memory that stores recurring pre-anomaly signatures. By reusing precursor knowledge across related entities, D-HTM can issue warnings prior to local anomaly onset while preserving HTM's online learning capabilities. We evaluate D-HTM on the Server Machine Dataset (SMD), the Soil Moisture Active Passive (SMAP) dataset, the Mars Science Laboratory (MSL) dataset, and a synthetic cascade benchmark designed to isolate precursor transfer. Experimental results demonstrate effective cross-entity warning propagation while maintaining competitive reactive anomaly detection performance. Across the real-world datasets, D-HTM provides an average warning lead time of 8.1 samples prior to anomaly onset. These findings demonstrate that transferable precursor structure can emerge within a shared SDR space and be reused for preemptive warning generation, extending HTM beyond isolated reactive detection toward distributed predictive reasoning.

cs.NE

Enhancing Biologically Inspired Hierarchical Temporal Memory with Hardware-Accelerated Reflex Memory

The rapid expansion of the Internet of Things (IoT) generates zettabytes of data that demand efficient unsupervised learning systems. Hierarchical Temporal Memory (HTM), a third-generation unsupervised AI algorithm, models the neocortex of the human brain by simulating columns of neurons to process and predict sequences. These neuron columns can memorize and infer sequences across multiple orders. While multiorder inferences offer robust predictive capabilities, they often come with significant computational overhead. The Sequence Memory (SM) component of HTM, which manages these inferences, encounters bottlenecks primarily due to its extensive programmable interconnects. In many cases, it has been observed that first-order temporal relationships have proven to be sufficient without any significant loss in efficiency. This paper introduces a Reflex Memory (RM) block, inspired by the Spinal Cord's working mechanisms, designed to accelerate the processing of first-order inferences. The RM block performs these inferences significantly faster than the SM. The integration of RM with HTM forms a system called the Accelerated Hierarchical Temporal Memory (AHTM), which processes repetitive information more efficiently than the original HTM while still supporting multiorder inferences. The experimental results demonstrate that the HTM predicts an event in 0.945 s, whereas the AHTM module does so in 0.125 s. Additionally, the hardware implementation of RM in a content-addressable memory (CAM) block, known as Hardware-Accelerated Hierarchical Temporal Memory (H-AHTM), predicts an event in just 0.094 s, significantly improving inference speed. Compared to the original algorithm \cite{bautista2020matlabhtm}, AHTM accelerates inference by up to 7.55x, while H-AHTM further enhances performance with a 10.10x speedup.

cs.LG

Quantification of Uncertainties in Probabilistic Deep Neural Network by Implementing Boosting of Variational Inference

Modern neural network architectures have achieved remarkable accuracies but remain highly dependent on their training data, often lacking interpretability in their learned mappings. While effective on large datasets, they tend to overfit on smaller ones. Probabilistic neural networks, such as those utilizing variational inference, address this limitation by incorporating uncertainty estimation through weight distributions rather than point estimates. However, standard variational inference often relies on a single-density approximation, which can lead to poor posterior estimates and hinder model performance. We propose Boosted Bayesian Neural Networks (BBNN), a novel approach that enhances neural network weight distribution approximations using Boosting Variational Inference (BVI). By iteratively constructing a mixture of densities, BVI expands the approximating family, enabling a more expressive posterior that leads to improved generalization and uncertainty estimation. While this approach increases computational complexity, it significantly enhances accuracy an essential tradeoff, particularly in high-stakes applications such as medical diagnostics, where false negatives can have severe consequences. Our experimental results demonstrate that BBNN achieves ~5% higher accuracy compared to conventional neural networks while providing superior uncertainty quantification. This improvement highlights the effectiveness of leveraging a mixture-based variational family to better approximate the posterior distribution, ultimately advancing probabilistic deep learning.

cs.LG