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379
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Citations since 2017
Publications
Publications (60)
High-performance Mass Memory Units are a key factor to process the vast amount of data of todays and upcoming space missions. In this work we present a high-performance but reliable mass memory unit for next generation satellite systems and deep space explorer missions. Peak data rates of up to 20 Gbps are targeted. To this end, a novel architectur...
This paper describes the protocol of the microgravity experiment BEAT (Ballistocardiography for Extraterrestrial Applications and Long-Term Missions). The current study makes use of signal acquisition of cardiac parameters with a high-precision Ballistocardiography (BCG)/Seismocardiography (SCG) measurement system, which is integrated in a smart sh...
For a decade, seismocardiography (SCG) on smartphones has been an interesting topic within the technical community, but mobile applications for this topic are rare on the market. The transition from laboratory to bedside application seems to have not yet been completed. To possibly increase the chances of a successful implementation, the added valu...
For cardiological datasets acquired via different methodologies, ECG signals that are recorded in parallel allow for relatively accurate matching. Some research issues, e.g., the identification of timings of the cardiac cycle in seismocardiography, require higher temporal resolutions. Therefore, we introduce a method derived from a feasibility stud...
We propose a comprehensive health monitoring of
astronauts which is based on Ballistocardiography (BCG). BCG
uses high-precision accelerometers to measure the motion of the
heart at the body surface. In contrast to conventional methods
(e.g. Electrocardiography (ECG)), BCG enables the derivation
of heart-related parameters that can otherwise only b...
Comprehensive health monitoring is highly relevant
for the safety of manned spaced missions. Ballistocardiography
(BCG) is a method for providing information of the heart
physiology by measuring accelerations on the body surface that
are caused by forwarded heart and blood movements in the
vascular system. In order to provide a sensor system with a...
This paper introduces Wireless Compose-2 (WICO2), which is an experiment for the International Space Station (ISS) in order to demonstrate the provision of a flexible and adaptable wireless network infrastructure integrated into a commodity item to conduct and execute low-power, low-weight and wireless experiments in the scientific and medical doma...
We present
ns-3-leo
, a module for the discrete event network simulator
ns-3
, which includes models for the network mobility and link characteristics of Low Earth Orbit (LEO) satellite mega-constellations. The initial goal has been to create a simulation environment in which existing routing protocols from the Wireless Sensor Network (WSN) and...
This paper introduces Wireless Compose-2, which is an experiment for the International Space Station (ISS) in order to demonstrate the provision of a flexible and adaptable wireless network infrastructure integrated in a commodity item to conduct and execute low-power, low-weight and wireless experiments in the scientific and medical domain. Recent...
Efficient data and signal processing is a key enabler in several space-related application areas. Within the last years complex applications like machine-learning-based earth observation, satellite-based quantum communications or 5G non-terrestrial networks have become very popular, but require a significant increase of the currently available proc...
The demand for satellites and space systems with ever-increasing avionics requirements is constantly growing, whether in the field of satellite communications or earth observation. Traditional architectures for Data Handling Systems (DHS) on satellites are reaching their limits in terms of flexibility, interoperability and reusability, while slowin...
Efficient data processing is a key enabler to compete with the excessive requirements of next generation satellite systems. In particular, connecting LEO satellite-constellations to existing terrestrial mobile communication services becomes increasingly important as this measure allows truly ubiquitous connectivity, but comes at the cost of signifi...
Dependability is a keyword within the recent discussion about the operation of Wireless Sensor Network (WSN) as a vital part of the ever-growing Internet of Things (IoT). However, while focusing on, e.g., reliable routing it is often neglected that the energy supply is an important factor to enable dependable WSN, and thus IoT operation. Using the...
Ballistocardiography (BCG) is the measurement of heart and cardiovascular related acceleration of the body. Due to the availability of inexpensive and small accelerometers, scientific interest in BCG increased in recent years. A variety of different measurement systems have emerged. Many of them lack on data quality, such as resolution and temporal...
Simulation is a common technique for the evaluation of new approaches and protocols in networked systems and provides many benefits. However, it is also well known that the relevance of the simulation results for real-world applications depends on the various models which are used within the simulation, e.g., for the characteristics of the radio co...
Ballistocardiography is a method to gain detailed information about body movements imparted by the ballistic forces associated with cardiac contraction. We measured using different setups and sensor positions to gain information of a reference signal of healthy adults. We used two resting state recordings and two recordings under physical stress (e...
Ballistocardiography (BCG) has gained more attention due to the fundamental goal of medical intervention in diagnostics and follow-up. BCG is particularly suitable for the study of heart failure, which a recent study has shown. The results of this working group shall be validated and reproduced with another study trial. Therefore, acceleration sens...
DUO is a co-processor-based energy harvesting solution that integrates the existing undervolting approach IdealVolting into the RIOT operating system. By integrating the existing approach into an operating system, the benefits of undervolting can be used in regular applications. The user can use IdealVolting along with existing applications and tak...
In research and education, a Wireless Sensor Network (WSN) may exist for its own sake and also the specific nodes used in such networks might be considered as study objects. However, in real applications the networks and the nodes are applied to solve real-world issues and, hence, have to be designed for their specific purpose. Since WSNs and accor...
The project SCARAB2 (Scalable, Robust and Adaptive on Board Ballistocardiography) aims to use Ballistocardiography (BCG) to monitor flight passengers. In order to show that recorded BCG data from flights give evaluable information even in the noisy environment of an airplane, we monitored a heart-healthy passenger using BCG. Furthermore, we show th...
With regard to the growing number of older adults, it needs smart solutions for fall prevention. Especially at geriatric institutions, the risk of falling is very high and frequently leads to injuries, resulting in serious consequences. We present the Inexpensive Node for Bed Exit Detection (INBED), a comprehensive signaling system for fall prevent...
Objective: In geriatric institutions, the risk of falling of patients is very high and frequently leads to fractures of the femoral neck, which can result in serious consequences and medical costs. With regard to the current numbers of elderly people, the need for smart solutions for the prevention of falls in clinical environments as well as in ev...
With regard to the growing number of wireless sensor network (WSN) and IoT long-term applications, energy harvesting becomes more and more popular i.a. due to the economical advantages compared to classical energy sources. Outdoor deployments for e.g. smart farming applications usually rely on solar-powered harvesters but this is not sufficient in...
Both reliability and robustness are required for applicationsin the field of wireless sensor networks and the internet ofthings. Testbeds are a usefool tool to verify both hardwareand software concepts under realistic conditions. However,existing testbeds often are fitted to specific use cases. Thispaper presents a software framework to build testb...
We describe a testbed for studying battery discharge behavior and the lifetime of wireless devices under controlled temperature conditions and present preliminary measurement results.
The Ballistocardiography (BCG) aims to analyze the ballistic forces on the heart in terms of vibrations that are transmitted to the body's surface. These vibrations can be measured by accelerometers. But instead of highly specialized analog sensors, we propose BCG based on commercially available digital accelerometers. To achieve this, we performed...
While success stories are likely to be reported, failures are rarely published -- even if a lot can be learned from them. In this paper we present experiences and findings from our testbed and WSN deployments. Our PotatoNet has been deployed on an agricultural area in 2015 to perform several WSN outdoor experiments while measuring the stress of pot...
Age-related falls are a widespreaded and expensive issue of society and with this a big challenge of gerontological research. Hence we present INBED - an inexpensive, modular and body-worn (medio-femoral) fall prevention system. Compared to existing solutions, INBED offers a more proper solution to prevent falls in clinical and elderly care environ...
The energy consumption of Wireless Sensor Networks (WSNs) correlates with the voltage level at which the nodes are powered—a lowered voltage leads to a prolonged lifetime of nodes and networks. Operating nodes at voltage levels below the recommendation—so-called undervolting—saves energy but is accompanied by an increased risk of failures.
In this...
It is a well-known fact that Wireless Sensor Networks (WSNs) that are exposed to real environmental conditions suffer from harsh temperatures. Yet, the temperature does not only have negative impact as the energy efficiency of processing units benefits from higher temperatures. The minimal voltage for correct operation of CMOS circuits is bounded b...
We present PotatoNet, an outdoor testbed for Wireless Sensor Networks (WSNs). Its primary focus is robustness, reliability and flexibility. PotatoNet is designed to operate without on-site maintenance for extended periods of time. It can withstand heat, dust and rain and has already been tested running outside for several months.
Adapting the voltage level of a processing unit to the actual system load leads to an increased energy efficiency. The aim is to extend the battery lifetime, but existing voltage scaling approaches still act with reserve. To reduce the energy consumption even further, it is possible to power the electric circuits below the specified voltage levels....
Much effort has been put into optimizing the energy-efficiency of wireless sensor nodes, but existing work exclusively focuses on the transceiver and the processing unit. Nevertheless, the peripheral energy consumption may dominate that of the entire node. We introduce the concept of a dynamically scalable peripheral voltage supply: Even for periph...
The energy consumption of electric circuits depends on the applied voltage level. This is used by dynamic voltage scaling approaches where the voltage is lowered up to a datasheet specified level. To reduce the energy consumption even further, it would be possible to power the electric circuits below the specified voltage levels. Considering Wirele...
In mobile applications, like wireless sensor networks, it is often inevitable to use a location-independent source of energy. Wherever the batteries capacity or inefficient energy harvesting limits the lifetime, other solutions have to be implemented to increase the energy efficiency. Dynamic Voltage Scaling (DVS) is a well known technique with the...
In mobile applications, like wireless sensor networks, it is often inevitable to use a location-independent source of energy. Wherever the batteries capacity or inefficient energy harvesting limits the lifetime, other solutions have to be implemented to increase the energy efficiency. Dynamic Voltage Scaling (DVS) is a well known technique with the...
INGA is a cost-efficient and universal wireless sensor node for activity monitoring and for general applications. INGA's architecture bases on an 8-bit Atmel microcontroller and runs Contiki OS and TinyOS "out of the box". The motivation to develop INGA was driven by the need for a reasonable, cheap and expandable node for several use cases: On the...
Fall detection, gait analysis and context recognition are examples of applications where capacitive accelerometers are widely used in health care. In most of the existing work, algorithms were developed for a specific platform and accelerometers were used without explicitly choosing a specific type. With this work we present an inexpensive and prac...
In this demo, we present some exemplary applications for INGA, a new and affordable wireless sensor node for general applications. INGA's hardware design is completely under open source license and it runs the open source operating system Contiki "out of the box". Several up-to-date sensors are included in the basic design and we developed it for r...
Nachdem wir einige Erfahrung auf dem Gebiet der drahtlosen Sensornetze gesammelt haben, haben wir uns entschieden, einen weiteren – eigenen – Sensorknoten zu entwick-eln. Ziel war es dabei, die Stärken vorhandener Sensorknoten möglichst zu kombinieren und die Schwächen zu minimieren. Außerdem war es uns wichtig, ein Set an aktuellen Sensoren anzubi...
Projects
Projects (3)
The objective of the project is to reduce the number of falls on geriatric wards. To archive this goal a sensor system based is developed and evaluated. The system is able to detect attempts to get up and informs nurses that can offer assistance. A prototype has been successfully evaluated in a pilot clinical trial over one year with 98 patients. The next steps are the development of a custom tailored sensor-node and a multi-center trial to fortify the first results.
