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1. A 65nm 63.3µW 15Mbps Transceiver with Switched-Capacitor Adiabatic Signaling and Combinatorial-Pulse-Position Modulation for Body-Worn Video-Sensing AR Nodes

   https://doi.org/10.1109/ISSCC42614.2022.9731793  

   Chatterjee, Baibhab; Datta, Arunashish; Nath, Mayukh; K, Gaurav Kumar; Modak, Nirmoy; Sen, Shreyas (February 2022, 2022 IEEE International Solid- State Circuits Conference (ISSCC))

   Recent advances in audio-visual augmented reality (AR) and virtual reality (VR) demands 1) high speed (>10Mbps) data transfer among wearable devices around the human body with 2) low transceiver (TRX) power consumption for longer lifetime, especially as communication energy/b is often orders of magnitude higher than computation energy/switching. While WiFi can transmit compressed video (HD 30fps, compressed @6-12Mbps), it consumes 50-to-400mW power. Bluetooth, on the other hand, is not designed for video transfer. New mm-Wave links can support the required bandwidth but do not support ultra-low-power (<1mW). In recent years, Human-Body Communication (HBC) [1]–[6] has emerged as a promising low-power alternative to traditional wireless communication. However, previous implementations of HBC transmitters (Tx) suffer from a large plate-to-plate capacitance (C p , between signal electrode and local ground of the transmitter) which results in a power consumption of aC p V2f (Fig. 16.6.1) in voltage-mode (VM) HBC. The recently proposed Resonant HBC [6] tries to overcome this problem by resonating C p with a parallel inductor (L). However, the operating frequency is usually < a few 10's of MHz for low-power Electro-Quasistatic (EQS) operation, resulting in a large/bulky inductor. Moreover, the resonant LC p circuit has a large settling time (≈5Q 2 RC P , where R is the effective series resistance of the inductor) for EQS frequencies which will limit the maximum symbol rate to <1MSps for a 21MHz carrier (the IEEE 802.15.6 standard for HBC), making resonant HBC infeasible for> 10Mb/s applications. 

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2. Learning on the Rings: Self-Supervised 3D Finger Motion Tracking Using Wearable Sensors

   https://doi.org/10.1145/3534587  

   Zhou, Hao; Lu, Taiting; Liu, Yilin; Zhang, Shijia; Gowda, Mahanth (July 2022, Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies)

   This paper presents ssLOTR (self-supervised learning on the rings), a system that shows the feasibility of designing self-supervised learning based techniques for 3D finger motion tracking using a custom-designed wearable inertial measurement unit (IMU) sensor with a minimal overhead of labeled training data. Ubiquitous finger motion tracking enables a number of applications in augmented and virtual reality, sign language recognition, rehabilitation healthcare, sports analytics, etc. However, unlike vision, there are no large-scale training datasets for developing robust machine learning (ML) models on wearable devices. ssLOTR designs ML models based on data augmentation and self-supervised learning to first extract efficient representations from raw IMU data without the need for any training labels. The extracted representations are further trained with small-scale labeled training data. In comparison to fully supervised learning, we show that only 15% of labeled training data is sufficient with self-supervised learning to achieve similar accuracy. Our sensor device is designed using a two-layer printed circuit board (PCB) to minimize the footprint and uses a combination of Polylactic acid (PLA) and Thermoplastic polyurethane (TPU) as housing materials for sturdiness and flexibility. It incorporates a system-on-chip (SoC) microcontroller with integrated WiFi/Bluetooth Low Energy (BLE) modules for real-time wireless communication, portability, and ubiquity. In contrast to gloves, our device is worn like rings on fingers, and therefore, does not impede dexterous finger motion. Extensive evaluation with 12 users depicts a 3D joint angle tracking accuracy of 9.07° (joint position accuracy of 6.55mm) with robustness to natural variation in sensor positions, wrist motion, etc, with low overhead in latency and power consumption on embedded platforms. 

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3. A Miniature Potentiostat for Impedance Spectroscopy and Cyclic Voltammetry in Wearable Sensor Integration

   Franulovic, Franci; Tabassum, Shawana (October 2024, arXivorg)

   A potentiostat is an analytical device and a crucial component in electrochemical instruments used for studying chemical reaction mechanisms, with potential applications in early diagnosis of disease or critical health conditions. Conventional potentiostats are typically benchtop devices designed for laboratory use, whereas a wearable potentiostat can be interfaced with biochemical sensors for disease diagnostics at home. This work presents a low-power potentiostat designed to connect with a sensor array consisting of eight to ten working electrodes. The potentiostat is capable of running Electrochemical Impedance Spectroscopy and Cyclic Voltammetry. The system is powered by lithium-ion batteries and uses Bluetooth for data transmission to the user. A single ARM M4 microcontroller, integrated with a Bluetooth low-energy radio module, controls the entire system. The accuracy, reliability, and power efficiency of the potentiostat were evaluated and compared against existing commercial benchtop potentiostats. Additionally, we have outlined future steps to enhance circuit miniaturization and power efficiency, aiming to develop fully integrated wearable sensing devices comparable in size to a wristwatch. 

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4. Collaborative Fall Detection using a Wearable Device and a Companion Robot

   Liang, Fei; Hernandez, Ricardo; Lu, Jiaxing; Moore, Jackson; Sheng, Weihua; Zhang, Senlin (June 2021, IEEE International Conference on Robotics and Automation)

   null (Ed.)

   Older adults who age in place face many health problems and need to be taken care of. Fall is a serious problem among elderly people. In this paper, we present the design and implementation of collaborative fall detection using a wearable device and a companion robot. First, we developed a wearable device by integrating a camera, an accelerometer and a microphone. Second, a companion robot communicates with the wearable device to conduct collaborative fall detection. The robot is also able to contact caregivers in case of emergency. The collaborative fall detection method consists of motion data based preliminary detection on the wearable device and video-based final detection on the companion robot. Both convolutional neural network (CNN) and long short-term memory (LSTM) are used for video-based fall detection. The experimental results show that the overall accuracy of video-based algorithm is 84%. We also investigated the relation between the accuracy and the number of image frames. Our method improves the accuracy of fall detection while maximizing the battery life of the wearable device. In addition, our method significantly increases the sensing range of the companion robot. 

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5. SAGE: A Split-Architecture Methodology for Efficient End-to-End Autonomous Vehicle Control

   https://doi.org/10.1145/3477006  

   Malawade, Arnav; Odema, Mohanad; Lajeunesse-degroot, Sebastien; Al Faruque, Mohammad Abdullah (October 2021, ACM Transactions on Embedded Computing Systems)

   Autonomous vehicles (AV) are expected to revolutionize transportation and improve road safety significantly. However, these benefits do not come without cost; AVs require large Deep-Learning (DL) models and powerful hardware platforms to operate reliably in real-time, requiring between several hundred watts to one kilowatt of power. This power consumption can dramatically reduce vehicles’ driving range and affect emissions. To address this problem, we propose SAGE: a methodology for selectively offloading the key energy-consuming modules of DL architectures to the cloud to optimize edge, energy usage while meeting real-time latency constraints. Furthermore, we leverage Head Network Distillation (HND) to introduce efficient bottlenecks within the DL architecture in order to minimize the network overhead costs of offloading with almost no degradation in the model’s performance. We evaluate SAGE using an Nvidia Jetson TX2 and an industry-standard Nvidia Drive PX2 as the AV edge, devices and demonstrate that our offloading strategy is practical for a wide range of DL models and internet connection bandwidths on 3G, 4G LTE, and WiFi technologies. Compared to edge-only computation, SAGE reduces energy consumption by an average of 36.13% , 47.07% , and 55.66% for an AV with one low-resolution camera, one high-resolution camera, and three high-resolution cameras, respectively. SAGE also reduces upload data size by up to 98.40% compared to direct camera offloading. 

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