Horst Hellbrück

• Technical University of Applied Sciences Lübeck

The placebo effect, a well-known phenomenon in medical and psychological research, is now being explored in the realm of Cyber-Physical & Human Systems (CPHS) with the introduction of the concept of a Cyber-Placebo. This approach involves simulating the presence and functionality of an artificial intelligence (AI) component within a CPHS, while in...

Among other methods, UWB-based multi-anchor localization systems have been established for industrial indoor localization systems. However, multi-anchor systems have high costs and installation effort. By exploiting the multipath propagation of the UWB signal, the infrastructure and thus the costs of conventional systems can be reduced. Our UWB Sin...

Among others, UWB-based multi anchor localization systems have been established for industrial indoor localization systems. However, multi anchor systems have high costs and installation effort. By exploiting the multipath propagation of the UWB signal, the infrastructure and thus the costs of conventional systems can be reduced. Our UWB Single Anc...

In this paper, we present a low-cost 5G-SA system based on edge-computing hardware with open-source components and off-the-shelf hardware. Our system is suitable for nomadic and ad-hoc 5G-SA use cases that require low power consumption and small space. We show a complete development covering how to prepare the operating system for the installation...

Rescue robots can play an important role in disaster situations, such as locating people for evacuations. This paper demonstrates how to transform an affordable consumer robot, such as the Loomo Segway, into an intelligent rescue robot. Our proof-of-concept shows how LoomoRescue can autonomously browse offices to locate people and how to detect the...

Device-free localization (DFL) systems exploit changes in the radio frequency channel by measuring, for example, the channel impulse response (CIR), to detect and localize obstacles within a target area. However, due to a lack of well-defined interfaces, missing modularization, as well as complex system configuration, it is difficult to deploy DFL...

This paper details the practical deployment of a 5G standalone campus network at TH Lübeck and the experiments which have been conducted in the network with respect to performance and security.

Objective: Due to ongoing technical progress, the ultrasonic measurement of blood pressure (BP) as an alternative to oscillometric measurement (NIBP) or the continuous non-invasive arterial pressure method (CNAP) moves further into focus. The US method offers several advantages over NIBP and CNAP, such as deep tissue penetration and the utilization...

In acoustic underwater communication and sonar applications, obstacles inside and outside the line-of-sight (LOS) affect signal propagation. Both reflection and diffraction occur in underwater communication and measurement systems due to these obstacles. To the best of our knowledge, the influence of diffraction and reflection is neither described...

Indoor positioning approaches are often based on electromagnetic wave signals with high frequency. However, signal reflections and the corresponding signal superpositions are challenging. As a result, there is still no indoor positioning technology established in commercial products, such as smartphones or smartwatches. Recent publications have sho...

Exploration of natural and artificial underwater structures is an actual field in development and research projects. Acoustic detection methods are well known and can be used to create seabed and subbottom profiles. The systems have limitations for detection of small objects, especially in presence of large acoustic reflectors. The detection of fla...

The measurement and analysis of the arterial pulse wave provides information about the state of vascular health. When measuring blood pressure according to Riva-Rocci, the systolic and diastolic blood pressure is measured non-invasively with an inflatable pressure cuff on the upper arm. Today’s blood pressure monitors analyze the pulse wave in refe...

Contact-free detection of human vital signs like heart rate and respiration rate will improve the patients’ comfort and enables long-term monitoring of newborns or bedridden patients. For that, reliable and safe measurement techniques are indispensable. The aim of this work is the development and comparison of novel ultrasonic and capacitive measur...

Short range wireless high data rate underwater communication systems become increasingly important. We provide the implementation, the setup and measurement results of the bit rate of our optical wireless underwater communication system in the Baltic Sea. In contrast to state of the art, our approach uses low frequency analog OFDM modulated light....

Content-Centric Networking (CCN) is a new paradigm for the future Internet where content is addressed by hierarchically organized names with the goal to replace TCP/IP networks. Unlike IP addresses, names have arbitrary length and are larger than the four bytes of IPv4 addresses. One important data structure in CCN is the Forwarding Information Bas...

Ultra-wideband signals have a variety of applications. An upcoming medical application is the detection of the heart rate of patients. However, current UWB systems provide poor resolution and are only able to detect vessels with a large diameter, e.g. the aorta. The detection and quantification of vascular dilation of thinner vessels is essential t...

Name-centric approaches provide maximum flexibility for applications, as a result, the future of Internet services is heading towards the increased importance of name-centric approaches. However, for the Internet of Things to become more name-centric, implementations of resource-constrained devices are required. Although there have been advances in...

The development process of short-range underwater communication systems consists of different phases. Each phase comprises a multitude of specific requirements to the development platform. Typically, the utilized hardware and software is custom-built for each phase and wireless technology. Thus, the available platforms are usually not flexible and...

Localization systems for mobile robots are a trade-off between accuracy, robustness and costs. Current solutions for landmark based indoor localization are either expensive or inaccurate and unreliable. Accurate solutions for instance require costly infrastructure and/or high computational power. Additionally, self-balancing robots have particular...

Linear and nonlinear filtering for state estimation (e.g. position estimation or sensor fusion) for indoor positioning and navigation applications is a challenging task. Sensor fusion becomes more important with cost-effective sensors being readily available. However, state estimation with recursive Bayesian filters for sensor fusion and filtering...

Standard medium access schemes sense the channel immediately prior transmission, but are blind during the transmission. Therefore, standard transceivers have limited cognitive capabilities which are important for operation in heterogeneous radio environments. Specifically, mobile interferers move gradually into the reception range before actually c...

The development process of an intelligent autonomous underwater vehicle (AUV) is based on experiential knowledge leading to uncertainty in the software development for the intelligent AUV control. In this work we suggest an expert system to implement the AUV control software because expert systems handle uncertainty during the development process b...

In range-based positioning systems, an altitude difference between tag and reference plane causes errors in two- and three-dimensional positioning. We analyze how these errors reduce accuracy of Local Positioning Systems (LPS) and show how compensation of the altitude difference improves performance of positioning. In this paper, we consider the av...

Development of underwater vehicles is a complex and challenging task. Especially the integration of components like sensors and actuators in a control loop is difficult and costly and requires many experiments. One of the difficulties is the lack of debugging facilities underwater. In this paper, we suggest a distributed system architecture and a t...

For development of an intelligent unmanned autonomous underwater vehicle (AUV), sensor data needs to be processed online for navigation and mission planning. In this work, we suggest a complete workflow and a processing chain to retrieve multibeam sonar data for AUV control. Our approach is based on the well-known image processing library OpenCV wh...

Localization is a key aspect of emergent applications in the medical, industrial and consumer field. In this article we survey state of the art, identify current challenges and issues for localization systems and suggest a unified layered architecture. The analysis reveals that challenges cannot be addressed in an isolated manner for example, energ...

Spectrum Sensing is one of the important tasks for wireless devices. By sensing the spectrum, wireless devices sense their radio environment and perform spectrum access accordingly to reduce collisions. Due to radio propagation effects and inherent noise in the measurements, performance of todays wireless technologies with individual spectrum sensi...

With anchor positions and measurements of distances between an object and anchors, positioning algorithms calculate the position of an object, e.g. via lateration. Positioning systems require calibration and configuration prior to operation. In the past, approaches employed reference nodes with GPS or other reference location systems to determine a...

Underwater communication gains increasing importance with rising need for autonomous underwater vehicles (AUV) and underwater infrastructure. Many applications require only a short range link up to a few meters, but high data rates up to several megabit per second. Optical communication is a promising solution for these applications. However, the p...

Wireless medical sensors are an emerging technology. Wireless sensors form networks and are placed in an unknown environment. For indoor scenarios context detection of medical sensors, e.g. removal of sensors from a specific room, is important. Current algorithms for context detection of wireless sensors are based on RF signals, but RF signal propa...

Indoor localization is important for medical and industrial application as well as for wireless emergency and security systems. For such applications an accuracy within a few meters is desired. Available radio based systems within that accuracy are neither cost effective nor easy to deploy. In this work, we suggest an approach called bi-phase measu...

Spectrum Sensing is one of the important tasks for the wireless devices but due to fading, shadowing and noise the performance of individual spectrum sensing devices is not ideal. Cooperative Sensing is seen as a way to improve the performance of individual spectrum sensing devices resultantly improving the efficient utilization of radio bandwidth...

In this paper, we motivate the need for a flexible and robust system architecture for autonomous underwater vehicles. We present a novel concept for integrating the expert system CLIPS into an AUV navigation environment DUNE. Our approach provides complete tool support for automatic source code generation and therefore allows fast and target-orient...

In standard medium access, transmitters perform spectrum sensing. Information about concurrent interferers is gained mainly during this sensing period. Especially during transmission respectively reception there is a blind gap where transmitter and receiver have limited capabilities to detect interferer. Standard radio receiver devices for IEEE 802...

Underwater communications receive more attention with rising need for autonomous underwater vehicles (AUV) and underwater infrastructure. Numerous applications e.g. video streams often require only a short-range wireless transmission up to several meters in seawater with high data rates up to several megabit per second. Radio transmission in high f...

The advances of electronics provide options for improved monitoring of patients in clinical environment. Medical applications like blood pressure monitoring require precise and wireless altitude measurement in indoor environment. An error of more than a few centimeters bears a risk of mistreatment of patients. Furthermore, user requirements like sm...

Indoor localization is important for logistics, industrial applications and for several consumer applications. In the area of logistics, e.g. warehouses, localization accuracy within a few meters is desired. Available radio based systems within that accuracy are neither cost effective nor easy to deploy. Distance estimation together with triangulat...

In recent past name-centric or content-centric networking (CCN) has gained substantial attention in the networking community. In a further development step name-centric service architecture enables the flexible placement and distribution of services in the network especially in a heterogeneous environment of wired and wireless (sensor) networks. Ho...

A method for determining a driving strategy for a driver of a motor vehicle includes receiving local information about a plurality of other motor vehicles using a receiving device, wherein the plurality of other motor vehicles are ahead of the motor vehicle and are relevant to the traffic situation. The method further includes recording the local i...

The goal of Service-Oriented Architectures (SOA) is to enable easy cooperation of a large number of computers and orchestration of services that are connected via a network. However, SOA for wireless sensor networks (WSN) and cyber-physical systems (CPS) is still a challenging task. Consequently, for design and development of large CPS like WSNs co...

Cooperative sensing has been identified as a potential improvement for cognitive radios to perceive their radio environment. In the past, algorithms have been developed by analysis and simulations exclusively. With cheaper hardware experimental platforms have been used for evaluation purpose recently. Simulations lack realistic propagation models f...

CCNx is the reference implementation for a content centric networking (CCN) protocol developed by the Palo Alto Research Center CCNx group. It serves also as reference for our CCN-WSN, a CCNx implementation for wireless sensor networks (WSN). Efficient data aggregation with CCN-WSN is a challenge. In order to collect data from source in the network...

Some medical applications require precise information of position and orientation of a patient as changes affect pressure condition inside the body. In this paper we focus on altitude estimation, where altitude is a distance, in vertical direction, between a reference and a point of a human body. We suggest equipping wireless sensor nodes with high...

In future Internet research, content centric networking (CCN) is a new promising approach. CCNx has been introduced recently as an open source protocol suite for CCN and implementation base for practical research. In wireless sensor networks (WSNs) research, data or content centric approaches like in-network processing and data aggregation are impo...

Spectrum sensing is a major task for wireless devices in order to improve coexistence among them in heterogeneous radio environments. Wireless communication includes at least two partners: transmitter and receiver. Therefore, cooperation between partners can improve the performance of spectrum sensing by reducing effort, improving sensing result or...

Embedded devices connected to the Internet will start an increasing growth of the Internet in near future. Wireless Sensor Networks (WSN) will play a major role in that growth. In the past several solutions were proposed to make sensor network sip capable. Today there are IPv6-Stacks available including web servers running on sensor nodes. However,...

Wireless systems based on WLAN (802.11), ZigBee (802.15.4) and Bluetooth (802.15.1) are continuously deployed in new applications covering consumer, industry or medical fields. Especially, Bluetooth is recommended by the Health-Care-Organization for medical applications as frequency hopping is considered as a robust scheme. However dealing with fre...

Since the 1990s the number of wireless devices increases and new areas of applications evolved. Therefore, frequency spectrum has become a scarce resource with no free frequencies left all over the world and interference between transmissions sharing the same frequency band is started to become one of the major problems in wireless transmission. Th...

In the past various protocols inspired by nature and biology have been proposed to disseminate or transfer data in mobile or static ad-hoc networks. Many of them are designed for usage in wireless sensor networks or vehicular ad-hoc networks. Recently, we have developed and designed a general purpose data dissemination protocol called AutoCast in t...

Current surveys and forecast predict that the number of wireless devices is going to increase tremendously. These wireless devices can be computers of all kinds, notebooks, netbooks, Smartphones and sensor nodes that evolve into real-world scenarios forming a “Real-World-Internet” in the future. In our work we focus on the Future Internet with smal...

The design and deployment of wireless networks needs careful planning including various tools for analysis, simulation and evaluation. Therefore, development of software to support deployment of wireless networks has been subject of intensive research for several years. In particular the evaluation of the influence of mobility remains a challenging...

Two years ago a survey of the wireless world research forum predicted that in the year 2017 there will be seven trillion wireless devices for seven billion humans which is equivalent to 1000 devices per human being on the average. The future will show if this incredible number will be reached but for sure we will see an increasing number of wireles...

We describe a distributed and self-regulated approach for the self-organisation of a large system of many self-driven, mobile objects, i.e., cars in traffic. Based on methods for mobile ad-hoc networks using short-distance communication between vehicles, and ideas from distributed algorithms, we consider reactions to specific traffic structures (e....

As part of our project AutoNomos, we have investigated traffic information and management systems that motivate the usage of new methods and tools inspired by Organic Computing paradigms. Current traffic monitoring and management approaches with stationary infrastructure lack flexibility with respect to system deployment and have difficulties with...

In the past a number of wireless standards evolved in industry and the consumer market that operate in the unlicensed ISM (Industrial, Scientific, Medical) Bands especially in the 2.4GHz range. Today these products are well engineered and standardized, so that more and more medical applications consider wireless transmission based on these standard...

Today, smartphones are one of the fastest growing markets in the world where Android is receiving more and more attention. In the beginning when users of smartphones use Internet applications with generic WWW-Browsers recently there is a trend that they are been replaced by special applications. For each service in the Internet e.g. Android users n...

The design and deployment of wireless networks needs careful planning including various tools for analysis, simulation and evaluation. Therefore, development of software to support deployment of wireless networks has been subject of intensive research for several years. In particular the evaluation of the influence of mobility remains a challenging...

There is an increasing trend to integrate sensor networks into the Internet, eventually resulting in an Internet of Things. Recent efforts of porting IPv6 to sensor networks turn sensor nodes into equitable Internet peers and RESTful Web Services on sensor nodes allow a distribution of the application logic among sensor nodes and more powerful Inte...

In recent years, tremendous progress has been made in understanding the dynamics of vehicle traffic flow and traffic congestion by interpreting traffic as a multiparticle system. This helps to explain the onset and persistence of many undesired phenomena, for example, traffic jams. It also reflects the apparent helplessness of drivers in traffic, w...

In recent years, tremendous progress has been made in understanding the dynamics of vehicle traffic flow and traffic congestion by interpreting traffic as a multi-particle system. This helps to explain the onset and persistence of many undesired phenomena, e.g., traffic jams. It also reflects the apparent helplessness of drivers in traffic, who fee...

Today's Internet is approaching architectural limits that are set up by its legacy architecture. It is based on technologies and algorithms that were developed about 30 years ago. Thus intensive research is done in the field of new protocols and algorithms fulfilling the needs of the Future Internet. We believe that wireless sensor networks (WSNs),...

Wireless sensor networks (WSN) have unique challenges and constraints. Sensor nodes e.g. have tough memory limitations. However, the latest advances in WSN research direct for an implementation of lightweight versions of Internet protocols like IPv6, TCP, and HTTP on sensor nodes. These protocols have challenging requirements. Especially, memory co...

Today Vehicular Ad-Hoc Networks (VANETS) are a promising field for increasing comfort and safety on the road. They have the potential to connect cars with each other and thereby extract information about road conditions or dangers that drivers can't ldquoseerdquo, e.g., the end of a traffic jam behind a curve. In this article we will focus on the p...

Today new medical applications evolve from large stationary devices to small and smart mobile systems that will enable e.g. more efficient post operative health care. These mobile systems that benefit from ongoing miniaturization and energy savings in hardware will allow continuous monitoring of patients accompanying and supporting therapy and dete...

Traffic applications, in which vehicles are equipped with a radio interface and communicate directly with each other and the road traffic infrastructure are a promising field for ad-hoc network technology. Vehicular applications reach from entertainment to traffic information systems, including safety aspects where warning messages can inform drive...

We propose a decentralized traffic information system—Auto-Nomos—that is based on a thorough investigation of the properties of traffic and recommends a hierarchical data aggregation and forwarding for providing individualized information and support to road users. Our approach differs from work in the field by consequently applying local rules and...

With the change from wired to wireless technologies the complexity of computer networks increases significantly. Distributed applications built on top of these wireless networks must be well designed to work in this difficult and changing envi-ronment. Especially the ad-hoc wireless communication between devices with wireless transceivers based on...

Vehicular Ad-Hoc Networks (VANETs) enable communication among vehicles as well as between vehicles and roadside infrastructures. Currently available software tools for VANET research still lack the ability to asses the usability of vehicular applications. In this article, we present Traffic Control Interface (TraCI) a technique for interlinking roa...