125 research outputs found
Special Issue on Wearable Computing and Machine Learning for Applications in Sports, Health, and Medical Engineering
Note: In lieu of an abstract, this is an excerpt from the first page.
Recent advancement in digital technologies is driving a remarkable transformation in sports, health, and medical engineering, aiming to achieve the accurate quantification of performance, well-being, and disease condition, and the optimization of sports, clinical, and therapeutic training and treatment programs. Traditionally, understanding and monitoring of functional performance and capacity has been performed in gait laboratories based on optoelectronic motion capture systems. However, gait laboratories in practical settings are often not readily available because the systems are costly and require trained experts to operate. Most importantly, when assessments are restricted to laboratory settings, they provide a narrow snapshot of function and do not capture functionality in natural free-living settings, thus representing a severely under-sampled view of an individualâs condition. The use of mobile and wearable technologies has been explored in many sports, health, and medical research studies examining individuals in âin-the-wildâ settings. Among the most important drivers of this transformation are (1) wearable sensors and (2) signal processing and machine learning algorithms. Wearable sensors are capable of collecting physical and/or physiological data continuously and seamlessly outside of laboratory settings. Signal processing and machine learning algorithms allow data-driven approaches for analyzing considerable amounts of multidimensional sensory data and for extracting important information relevant to the mentioned application areas (e.g., validating the efficacy of sports training, health benefits, and chronic disease progression). These technologies together would support how sports and clinical professionals understand and interpret individualsâ performance more objectively, and enable proactive, evidence-based, and personalized management systems
Online at Will: A Novel Protocol for Mutual Authentication in Peer-to-Peer Networks for Patient-Centered Health Care Information Systems
Patient-centered health care information systems (PHSs) on peer-to-peer (P2P) networks promise decentralization benefits. P2P PHSs, such as decentralized personal health records or interoperable Covid-19 proximity trackers, can enhance data sovereignty and resilience to single points of failure, but the openness of P2P networks introduces new security issues. We propose a novel, simple, and secure mutual authentication protocol that supports offline access, leverages independent and stateless encryption services, and enables patients and medical professionals to establish secure connections when using P2P PHSs. Our protocol includes a virtual smart card (software-based) feature to ease integration of authentication features of emerging national health-IT infrastructures. The security evaluation shows that our protocol resists most online and offline threats while exhibiting performance comparable to traditional, albeit less secure, password-based authentication methods. Our protocol serves as foundation for the design and implementation of P2P PHSs that will make use of P2P PHSs more secure and trustworthy
How to Learn from Risk: Explicit Risk-Utility Reinforcement Learning for Efficient and Safe Driving Strategies
Autonomous driving has the potential to revolutionize mobility and is hence
an active area of research. In practice, the behavior of autonomous vehicles
must be acceptable, i.e., efficient, safe, and interpretable. While vanilla
reinforcement learning (RL) finds performant behavioral strategies, they are
often unsafe and uninterpretable. Safety is introduced through Safe RL
approaches, but they still mostly remain uninterpretable as the learned
behaviour is jointly optimized for safety and performance without modeling them
separately. Interpretable machine learning is rarely applied to RL. This paper
proposes SafeDQN, which allows to make the behavior of autonomous vehicles safe
and interpretable while still being efficient. SafeDQN offers an
understandable, semantic trade-off between the expected risk and the utility of
actions while being algorithmically transparent. We show that SafeDQN finds
interpretable and safe driving policies for a variety of scenarios and
demonstrate how state-of-the-art saliency techniques can help to assess both
risk and utility.Comment: 8 pages, 5 figure
Estimation of Gait Kinematics and Kinetics from Inertial Sensor Data Using Optimal Control of Musculoskeletal Models
Inertial sensing enables field studies of human movement and ambulant assessment of patients. However, the challenge is to obtain a comprehensive analysis from low-quality data and sparse measurements. In this paper, we present a method to estimate gait kinematics and kinetics directly from raw inertial sensor data performing a single dynamic optimization. We formulated an optimal control problem to track accelerometer and gyroscope data with a planar musculoskeletal model. In addition, we minimized muscular effort to ensure a unique solution and to prevent the model from tracking noisy measurements too closely. For evaluation, we recorded data of ten subjects walking and running at six different speeds using seven inertial measurement units (IMUs). Results were compared to a conventional analysis using optical motion capture and a force plate. High correlations were achieved for gait kinematics (rho \u3e= 0.93) and kinetics (rho \u3e= 0.90). In contrast to existing IMU processing methods, a dynamically consistent simulation was obtained and we were able to estimate running kinetics. Besides kinematics and kinetics, further metrics such as muscle activations and metabolic cost can be directly obtained from simulated model movements. In summary, the method is insensitive to sensor noise and drift and provides a detailed analysis solely based on inertial sensor data
Contrastive Language-Image Pretrained Models are Zero-Shot Human Scanpath Predictors
Understanding the mechanisms underlying human attention is a fundamental
challenge for both vision science and artificial intelligence. While numerous
computational models of free-viewing have been proposed, less is known about
the mechanisms underlying task-driven image exploration. To address this gap,
we present CapMIT1003, a database of captions and click-contingent image
explorations collected during captioning tasks. CapMIT1003 is based on the same
stimuli from the well-known MIT1003 benchmark, for which eye-tracking data
under free-viewing conditions is available, which offers a promising
opportunity to concurrently study human attention under both tasks. We make
this dataset publicly available to facilitate future research in this field. In
addition, we introduce NevaClip, a novel zero-shot method for predicting visual
scanpaths that combines contrastive language-image pretrained (CLIP) models
with biologically-inspired neural visual attention (NeVA) algorithms. NevaClip
simulates human scanpaths by aligning the representation of the foveated visual
stimulus and the representation of the associated caption, employing
gradient-driven visual exploration to generate scanpaths. Our experimental
results demonstrate that NevaClip outperforms existing unsupervised
computational models of human visual attention in terms of scanpath
plausibility, for both captioning and free-viewing tasks. Furthermore, we show
that conditioning NevaClip with incorrect or misleading captions leads to
random behavior, highlighting the significant impact of caption guidance in the
decision-making process. These findings contribute to a better understanding of
mechanisms that guide human attention and pave the way for more sophisticated
computational approaches to scanpath prediction that can integrate direct
top-down guidance of downstream tasks
Active Learning of Ordinal Embeddings: A User Study on Football Data
Humans innately measure distance between instances in an unlabeled dataset
using an unknown similarity function. Distance metrics can only serve as proxy
for similarity in information retrieval of similar instances. Learning a good
similarity function from human annotations improves the quality of retrievals.
This work uses deep metric learning to learn these user-defined similarity
functions from few annotations for a large football trajectory dataset. We
adapt an entropy-based active learning method with recent work from triplet
mining to collect easy-to-answer but still informative annotations from human
participants and use them to train a deep convolutional network that
generalizes to unseen samples. Our user study shows that our approach improves
the quality of the information retrieval compared to a previous deep metric
learning approach that relies on a Siamese network. Specifically, we shed light
on the strengths and weaknesses of passive sampling heuristics and active
learners alike by analyzing the participants' response efficacy. To this end,
we collect accuracy, algorithmic time complexity, the participants' fatigue and
time-to-response, qualitative self-assessment and statements, as well as the
effects of mixed-expertise annotators and their consistency on model
performance and transfer-learning.Comment: 23 pages, 17 figure
An Overview of Smart Shoes in the Internet of Health Things: Gait and Mobility Assessment in Health Promotion and Disease Monitoring
New smart technologies and the internet of things increasingly play a key role in healthcare and wellness, contributing to the development of novel healthcare concepts. These technologies enable a comprehensive view of an individualâs movement and mobility, potentially supporting healthy living as well as complementing medical diagnostics and the monitoring of therapeutic outcomes. This overview article specifically addresses smart shoes, which are becoming one such smart technology within the future internet of health things, since the ability to walk defines large aspects of quality of life in a wide range of health and disease conditions. Smart shoes offer the possibility to support prevention, diagnostic work-up, therapeutic decisions, and individual disease monitoring with a continuous assessment of gait and mobility. This overview article provides the technological as well as medical aspects of smart shoes within this rising area of digital health applications, and is designed especially for the novel reader in this specific field. It also stresses the need for closer interdisciplinary interactions between technological and medical experts to bridge the gap between research and practice. Smart shoes can be envisioned to serve as pervasive wearable computing systems that enable innovative solutions and services for the promotion of healthy living and the transformation of health care
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