Dimitri Kraft

Proceedings of the 9th International Conference on Sensor Network

International Joint Conference on Computer Vision and Computer Graphics Theory and Applications (VISIGRAPP) <15, 2020, Valetta, Malta>

Natural and artificial joints of a human body are emitting vibration and sound during the movement. The sound and vibration pattern of a joint is characteristic and changes due to damage, uneven tread wear, injuries, or other influences. Hence, the vibration and sound analysis enables an estimation of the joint condition. This kind of analysis, vibroarthrography (VAG), allows the analysis of diseases like arthritis or osteoporosis and might determine trauma, inflammation, or misalignment. The classification of the vibration and sound data is very challenging and needs a comprehensive annotated data base. Current existing data bases are very limited and insufficient for deep learning or artificial intelligent approaches. In this paper, we describe a new concept of the design of a vibroarthrography system using a sensor network. We discuss the possible improvements and we give an outlook for the future work and application fields of VAG.

2020 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings

45th International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2020) <45, 2020, Barcelona, Spain>

Electrocardiograms constitute the key diagnostic tool for cardiologists. While their diagnostic value is yet unparalleled, electrode placement is prone to errors, and sticky electrodes pose a risk for skin irritations and may detach in long-term measurements. Heart.AI presents a fundamentally new approach, transforming motion-based seismocardiograms into electrocardiograms interpretable by cardiologists. Measurements are conducted simply by placing a sensor on the user’s chest. To generate the transformation model, we trained a convolutional autoencoder with the publicly available CEBS dataset. The transformed ECG strongly correlates with the ground truth (r=.94, p<.01), and important features (number of R-peaks, QRS-complex durations) are modeled realistically (Bland-Altman analyses, p>0.12). On a 5- point Likert scale, 15 cardiologists rated the morphological and rhythmological validity as high (4.63/5 and 4.8/5, respectively). Our electrodeless approach solves crucial problems of ECG measurements while being scalable, accessible and inexpensive. It contributes to telemedicine, especially in low-income and rural regions worldwide.

iWOAR 2019

International Workshop on Sensor-based Activity Recognition (iWOAR) <6, 2019, Rostock, Germany>

ACM International Conference Proceedings Series

The knee is the largest joint in the human body. Unfortunately, some hips or knee joints suffer on inflammation, misalignment, degeneration, trauma as well as diseases like arthritis or osteoporosis. Modern medicine can measure the joint condition or, if the joint is worn out, even exchange the joint with an implant. Endoprosthetic implants are artificial devices that replaces a weak body part such as osteoarthritic knee or hip joints. The lifespan of joint endoprostheses are also limited and depend on several factors, and it varies for each patient. In most cases total knee or hip endoprostheses need to be replaced after approximately 15 to 20 years, but some implants need an exchange after a few years due to several causes. Current methods to examine the condition of joint endoprostheses and natural joints are X-ray, Computed tomography (CT) and Magnetic Resonance Imaging (MRI). In rare cases implant integrated sensors were used. The usage of these methods and the analysis of the assessed data require medical and data experts. However, a vague estimation of the joint condition can also be performed by external vibration and sound analysis of the endoprosthesis and natural joint during movements. This paper describes several approaches of external vibration and sound analysis as a survey

Rostock, Univ., Master Thesis, 2019