In the modern digital era, passwords remain a common yet vulnerable means of user authentication, making them susceptible to many attacks. As a result, Two-Factor Authentication (2FA) emerged, offering heightened security. However, its two-step verification process can discourage widespread adoption. This study explores the potential of Electroencephalography (EEG) signals as an innovative alternative to 2FA by combining the authentication and validation processes into a single step. Our research examines different techniques to extract features from raw EEG signals, including band power extraction, statistical features, wavelet features, and Shannon Entropy, to capture these signals’ unique and intricate patterns. Additionally, we perform a comprehensive comparative analysis of discriminative classifiers such as Support Vector Machines (SVMs), k-Nearest Neighbors (k-NNs), Multilayer Perceptron’s (MLPs), Random Forest, and Gradient Boosting to determine the most effective approach for EEG signal-based authentication. We utilize a user-friendly web application that connects with cloud resources to validate our findings and provide a tangible demonstration. This application securely receives and stores EEG signals, allowing them to be evaluated against pre-trained machine-learning models. Our findings highlight the significant potential of EEG signals as a dependable, robust, and secure approach for user authentication, paving the way toward a future where passwords and complex 2FA processes can be substituted with a more convenient and reliable EEG-based authentication system.

In response to innovations in machine learning (ML) models, production workloads changed radically and rapidly. TPU v4 is the fifth Google domain specific architecture (DSA) and its third supercomputer for such ML models. Optical circuit switches (OCSes) dynamically reconfigure its interconnect topology to improve scale, availability, utilization, modularity, deployment, security, power, and performance; users can pick a twisted 3D torus topology if desired. Much cheaper, lower power, and faster than Infiniband, OCSes and underlying optical components are <5% of system cost and <3% of system power. Each TPU v4 includes SparseCores, dataflow processors that accelerate models that rely on embeddings by 5x--7x yet use only 5% of die area and power. Deployed since 2020, TPU v4 outperforms TPU v3 by 2.1x and improves performance/Watt by 2.7x. The TPU v4 supercomputer is 4x larger at 4096 chips and thus nearly 10x faster overall, which along with OCS flexibility and availability allows a large language model to train at an average of ~60% of peak FLOPS/second. For similar sized systems, it is ~4.3x--4.5x faster than the Graphcore IPU Bow and is 1.2x--1.7x faster and uses 1.3x--1.9x less power than the Nvidia A100. TPU v4s inside the energy-optimized warehouse scale computers of Google Cloud use ~2--6x less energy and produce ~20x less CO2e than contemporary DSAs in typical on-premise data centers.

Many architects believe that major improvements in cost-energy-performance must now come from domain-specific hardware. This paper evaluates a custom ASIC---called a Tensor Processing Unit (TPU) --- deployed in datacenters since 2015 that accelerates the inference phase of neural networks (NN). The heart of the TPU is a 65,536 8-bit MAC matrix multiply unit that offers a peak throughput of 92 TeraOps/second (TOPS) and a large (28 MiB) software-managed on-chip memory. The TPU's deterministic execution model is a better match to the 99th-percentile response-time requirement of our NN applications than are the time-varying optimizations of CPUs and GPUs that help average throughput more than guaranteed latency. The lack of such features helps explain why, despite having myriad MACs and a big memory, the TPU is relatively small and low power. We compare the TPU to a server-class Intel Haswell CPU and an Nvidia K80 GPU, which are contemporaries deployed in the same datacenters. Our workload, written in the high-level TensorFlow framework, uses production NN applications (MLPs, CNNs, and LSTMs) that represent 95% of our datacenters' NN inference demand. Despite low utilization for some applications, the TPU is on average about 15X -- 30X faster than its contemporary GPU or CPU, with TOPS/Watt about 30X -- 80X higher. Moreover, using the CPU's GDDR5 memory in the TPU would triple achieved TOPS and raise TOPS/Watt to nearly 70X the GPU and 200X the CPU.