Nils Yannick Hammerla

Nils Yannick Hammerla
Newcastle University | NCL · School of Computing Science

Diplom Informatik

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37
Publications
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2,453
Citations

Publications

Publications (37)
Article
Full-text available
BACKGROUND: Physical activity has not been objectively measured in prospective cohorts with sufficiently large numbers to reliably detect associations with multiple health outcomes. Technological advances now make this possible. We describe the methods used to collect and analyse accelerometer measured physical activity in over 100,000 participants...
Data
Minimum wear time criterion. One challenge is to determine the minimum amount of time participants should wear an accelerometer to get a reliable measure of their physical activity status. Therefore, using 29 765 participants who had complete wear time compliance, we simulated the effect of only having 24–168 hours of data (1–7 days). Using intracl...
Article
Full-text available
Background Late-life depression (LLD) is associated with a decline in physical activity. Typically this is assessed by self-report questionnaires and, more recently, with actigraphy. We sought to explore the utility of a bespoke activity monitor to characterize activity profiles in LLD more precisely. Method The activity monitor was worn for 7 day...
Conference Paper
Expressiveness, which we define as the extent to which rich and complex intent can be conveyed through action, is a vital aspect of many human interactions. For instance, paint on canvas is said to be an expressive medium, because it affords the artist the ability to convey multifaceted emotional intent through intricate manipulations of a brush. T...
Conference Paper
We present a video demonstration of how information about hand movements, generated from a wrist-worn IMU (inertial measurement unit), can be used to provide expressiveness to touch-based interactions. The IMU identifies features that were not previously accessible, such as instantaneous force, wrist roll and pitch. We demonstrate a range of applic...
Conference Paper
We present an interactivity demonstration of Expressy. A system that augments existing touchscreen devices with a variety of continuous expressive interaction capabilities, using movement data from a wrist-worn IMU. Our demonstration comprises a set of applications that show how the expressive touch interaction capabilities, offered by Expressy, ca...
Conference Paper
Human activity recognition (HAR) in ubiquitous computing is beginning to adopt deep learning to substitute for well-established analysis techniques that rely on hand-crafted feature extraction and classification techniques. From these isolated applications of custom deep architectures it is, however, difficult to gain an overview of their suitabili...
Article
Full-text available
Human activity recognition (HAR), i.e., the automated detection and classification of specific activities that a person pursues, is one of the core concerns of mobile and ubiquitous computing. Multimodal sensing facilities of modern mobile devices allow for detailed capture of contextual information, most importantly movement data recorded with ine...
Conference Paper
Full-text available
Upper limb weakness is one of the most distressing, long-term consequences of stroke and can be difficult to rehabilitate due to an overreliance on the opposing limb in everyday life. Previous studies have shown potential for cueing to improve upper limb rehabilitation, although these have been conducted in clinical settings. In this paper we descr...
Article
Management of Parkinson's Disease (PD) could be improved significantly if reliable, objective information about fluctuations in disease severity can be obtained in ecologically valid surroundings such as the private home. Although automatic assessment in PD has been studied extensively, so far no approach has been devised that is useful for clinica...
Conference Paper
Objective: There is great need for an objective method of symptom assessment in Parkinson's disease (PD) to enable better treatment decisions and to assist evaluation of new therapies. In this work we present the use of wrist-worn accelerometers and artificial neural networks (ANN) to evaluate patients' motor symptoms during a prolonged period of u...
Conference Paper
Objective: Remote, prolonged monitoring of symptoms in Parkinson's disease (PD) would assist treatment decisions and evaluation of new treatments. It is unknown whether symptom monitoring with body-worn sensors is acceptable to PD patients due to a lack of high quality previous research. Background: Previously, van Someren et al. (JNS 1993. 117(1-2...
Conference Paper
The assessment of surgical skills is an essential part of medical training. The prevalent manual evaluations by expert surgeons are time consuming and often their outcomes vary substantially from one observer to another. We present a video-based framework for automated evaluation of surgical skills based on the Objective Structured Assessment of Te...
Article
We propose a sparse-coding framework for activity recognition in ubiquitous and mobile computing that alleviates two fundamental problems of current supervised learning approaches. (i) It automatically derives a compact, sparse and meaningful feature representation of sensor data that does not rely on prior expert knowledge and generalizes extremel...
Conference Paper
Full-text available
It is challenging to precisely identify the boundary of activities in order to annotate the activity datasets required to train activity recognition systems. This is the case for experts, as well as non-experts who may be recruited for crowd-sourcing paradigms to reduce the annotation effort or speed up the process by distributing the task over mul...
Conference Paper
Full-text available
Health and wellbeing of dogs, either domesticated pets or service animals, are major concerns that are taken seriously for ethical, emotional, and financial reasons. Welfare as- sessments in dogs rely on objective observations of both fre- quency and variability of individual behaviour traits, which is often difficult to obtain in a dog’s everyday...
Conference Paper
The majority of activity recognition systems in wearable com- puting rely on a set of statistical measures, such as means and moments, extracted from short frames of continuous sensor measurements to perform recognition. These features implicitly quantify the distribution of data observed in each frame. However, feature selection remains challengin...
Conference Paper
Full-text available
In recent years the sport of climbing has seen consistent in- crease in popularity. Climbing requires a complex skill set for successful and safe exercising. While elite climbers re- ceive intensive expert coaching to refine this skill set, this progression approach is not viable for the amateur popu- lation. We have developed ClimbAX – a climbing...
Conference Paper
Full-text available
We present a novel approach to graspable interfaces using Touchbugs, actuated physical objects for interacting with interactive surface computing applications. Touchbugs are active tangibles that are able to move across surfaces by employing vibrating motors and can communicate with camera based multi-touch surfaces using infrared LEDs. Touchbug's...
Conference Paper
Online gaming is very popular and has gained some recognition as the so called e-sport over the last decade. However, in particular First Person Shooter (FPS) games suffer from the development of sophisticated cheating methods such as aiming robots (aimbot), which can boost the players ability to acquire and track targets by the illicit use of inte...
Conference Paper
Full-text available
Severe behavior problems of children with developmental disabilities often require intervention by specialists. These specialists rely on direct observation of the behavior, usu- ally in a controlled clinical environment. In this paper, we present a technique for using on-body accelerometers to as- sist in automated classification of problem behavi...
Conference Paper
Full-text available
The common practice of manual synchronization of body- worn, logging accelerometers and video cameras is imprac- tical for integration into everyday practice for applications such as real-world behavior analysis. We significantly ex- tend an existing technique for automatic cross-modal syn- chronization and evaluate its performance in a realistic e...
Conference Paper
First Person Shooter (FPS) is a popular genre in online gaming, unfortunately not everyone plays the game fairly, and this hinders the growth of the industry. The aiming robot (aimbot) is a common cheating mechanism employed in this genre, it differs from many other common online bots in that there is a human operating alongside the bot, and thus t...
Conference Paper
Background: Behavior problems such as destructive behaviors, aggression, and self-injury are part of the clinical picture of autism (Hartley et al., 2008), and thus represent the targets of many intervention efforts (Horner et al., 2002). Accurate data on the frequency and intensity of these behaviors is key to understanding why and when they occur...
Conference Paper
Full-text available
We present GymSkill, a personal trainer for ubiquitous monitoring and assessment of physical activity using standard fitness equipment. The system records and analyzes exercises using the sensors of a personal smartphone attached to the gym equipment. Novel fine-grained activity recognition techniques based on pyramidal Principal Component Breakdow...
Article
Full-text available
We report on our research on GymSkill, a smartphone system for com- prehensive physical exercising support, from sensor data logging, activity recognition to on-top skill assessment, using the phones built-in sensors. In two iterations, we used principal component breakdown analysis (PCBA) and criteria-based scores for individualized and personaliz...
Conference Paper
Full-text available
We present the development of a socially acceptable cueing device for drooling in Parkinson's disease (PD). Sialorrhea, or drooling, is a significant problem associated with PD and has a strong negative emotional impact on those who experience it. Previous studies have shown the potential for managing drooling by using a cueing device. However, the...
Article
Full-text available
Statistical modelling techniques for automatic reading systems substantially rely on the availability of compact and meaningful feature representations. State-of-the-art feature extraction for offline handwriting recognition is usually based on heuristic approaches that describe either basic geometric properties or statistical distributions of raw...
Conference Paper
Full-text available
Feature extraction for activity recognition in context-aware ubiquitous computing applications is usually a heuristic process, informed by underlying domain knowledge. Relying on such explicit knowledge is problematic when aiming to generalize across different application domains. We investigate the potential of recent machine learning methods for...
Conference Paper
Full-text available
Information about the motor performance, i.e. how well an activity is performed, is valuable information for a variety of novel applications in Activity Recognition (AR). Its as- sessment represents a significant challenge, as requirements depend on the specific application. We develop an approach to quantify one aspect that many domains share – th...
Conference Paper
We present the development of a socially acceptable cueing device for drooling in Parkinson’s disease (PD). Sialorrhea, or drooling, is a significant problem associated with PD and has a strong negative emotional impact on those who experience it. Previous studies have shown the potential for managing drooling by using a cueing device. However, the...

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