Björn Friedrich

Dr. Björn Friedrich

orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 February 2021 in Healthcare
Verified
Journal Article
Open access
PDF file
Björn FriedrichBjörn Friedrich
Björn Friedrich
SLSandra Lau
Sandra Lau
LELena Elgert
Lena Elgert
JBJürgen M. Bauer
Jürgen M. Bauer
AHAndreas Hein
Andreas Hein
Since older adults are prone to functional decline, using Inertial-Measurement-Units (IMU) for mobility assessment score prediction gives valuable information to physicians to diagnose changes in mobility and physical performance at an early stage and increases the chances of rehabilitation. This research introduces an approach for predicting the score of the Timed Up & Go test and Short-Physical-Performance-Battery assessment using IMU data and deep neural networks. The approach is validated on real-world data of a cohort of 20 frail or (pre-) frail older adults of an average of 84.7 years. The deep neural networks achieve an accuracy of about 95% for both tests for participants known by the network.

10 May 2022 in Applied Intelligence
Verified
Journal Article
Open access
PDF file
Björn FriedrichBjörn Friedrich
Björn Friedrich
TSTaishi Sawabe
Taishi Sawabe
AHAndreas Hein
Andreas Hein
Abnormal behaviour can be an indicator for a medical condition in older adults. Our novel unsupervised statistical concept drift detection approach uses variational autoencoders for estimating the parameters for a statistical hypothesis test for abnormal days. As feature, the Kullback–Leibler divergence of activity probability maps derived from power and motion sensors were used. We showed the general feasibility (min. F1-Score of 91 %) on an artificial dataset of four concept drift types. Then we applied our new method to our real–world dataset collected from the homes of 20 (pre–)frail older adults (avg. age 84.75 y). Our method was able to find abnormal days when a participant suffered from severe medical condition.

10 September 2020
Verified
Conference Paper
Open access
Björn FriedrichBjörn Friedrich
Björn Friedrich
CLCarolin Lübbe
Carolin Lübbe
AHAndreas Hein
Andreas Hein
The broad availability of smartphones and Inertial Measurement Units in particular brings them into focus of recent research. Inertial Measurement Unit data is used for a variety of tasks. One important task is the classification of the mode of transportation. In this paper, we present a deep-learning-based algorithm, that combines long-short-term-memory (LSTM) layer and convolutional layer to classify eight different modes of transportation on the Sussex-Huawei Locomotion-Transportation (SHL) dataset. The inputs of our model are the accelerometer, gyroscope, linear acceleration, magnetometer, gravity and pressure values as well as the orientation information. We achieve a F1 score of 98.96 % on our private test set. We participated as team 103114102106|8 in the Sussex-Huawei Locomotion-Transportation (SHL) recognition challenge.

9 September 2019
Verified
Conference Paper
Open access
Björn FriedrichBjörn Friedrich
Björn Friedrich
BCBenjamin Cauchi
Benjamin Cauchi
AHAndreas Hein
Andreas Hein
SFSebastian Fudickar
Sebastian Fudickar
This article introduce the architecture of a Long-Short-Term-Memory network for classifying transportation-modes via smartphone data and evaluates its accuracy. By using a Long-Short-Term-Memory with common preprocessing steps such as normalisation for classification tasks an F1-Score accuracy of 63.68 % was achieved with an internal test dataset. We participated as team "GanbareAMT" in the "SHL recognition challenge".

31 July 2023 in Scientific Reports
Verified
Journal Article
Open access
PDF file
Björn FriedrichBjörn Friedrich
Björn Friedrich
LELena Elgert
Lena Elgert
DEDaniel Eckhoff
Daniel Eckhoff
JBJürgen Martin Bauer
Jürgen Martin Bauer
AHAndreas Hein
Andreas Hein
Functional decline in older adults can lead to an increased need of assistance or even moving to a nursing home. Utilising home automation, power and wearable sensors, our system continuously keeps track of the functional status of older adults through monitoring their daily life and allows health care professionals to create individualised rehabilitation programmes based on the changes in the older adult’s functional capacity and performance in daily life. The system uses the taxonomy of the International Classification of Functioning, Disability and Health (ICF) by the World Health Organization (WHO). It links sensor data to five ICF items from three ICF categories and measures their change over time. We collected data from 20 (pre-)frail older adults (aged $$\ge$$ ≥ 75 years) during a 10-month observational randomised pilot intervention study. The system successfully passed the first pre-clinical validation step on the real-world data of the OTAGO study. Furthermore, an initial test with a medical professional showed that the system is intuitive and can be used to design personalised rehabilitation measures. Since this research is in an early stage further clinical studies are needed to fully validate the system.

29 December 2020 in Sensors
Verified
Journal Article
Open access
PDF file
Björn FriedrichBjörn Friedrich
Björn Friedrich
CLCarolin Lübbe
Carolin Lübbe
AHAndreas Hein
Andreas Hein
The broad availability of smartphones and Inertial Measurement Units in particular brings them into the focus of recent research. Inertial Measurement Unit data is used for a variety of tasks. One important task is the classification of the mode of transportation. In the first step, we present a deep-learning-based algorithm that combines long-short-term-memory (LSTM) layer and convolutional layer to classify eight different modes of transportation on the Sussex–Huawei Locomotion-Transportation (SHL) dataset. The inputs of our model are the accelerometer, gyroscope, linear acceleration, magnetometer, gravity and pressure values as well as the orientation information. In the second step, we analyze the contribution of each sensor modality to the classification score and to the different modes of transportation. For this analysis, we subtract the baseline confusion matrix from a confusion matrix of a network trained with a left-out sensor modality (difference confusion matrix) and we visualize the low-level features from the LSTM layers. This approach provides useful insights into the properties of the deep-learning algorithm and indicates the presence of redundant sensor modalities.