Dipl.-Ing. (FH) Gunther Ardelt
|Adress||Technische Hochschule Lübeck, Electrical Engineering and Computer Science
Mönkhofer Weg 239
D-23562 Lübeck, Deutschland
|Phone||+49 (0)451 300-5352|
Refereed Articles and Book Chapters
|||Towards Intrinsic Molecular Communication Using Isotopic Isomerism , In Open Journal of Internet Of Things (OJIOT) RonPub, volume 4, 2018. [bib] [pdf] [abstract]|
In this paper we introduce a new approach for molecular communication (MC). The proposed method uses isotopomers as symbols in a communication scenario, and we name this approach isotopic molecular communication (IMC). We propose a modulation scheme based on isotopic isomerism, where symbols are encoded via isotopes in molecules. This can be advantageous in applications where the communication has to be independent from chemical molecular concentration. Application scenarios include nano communications with isotopes in a macroscopic environment, i.e. encoding freshwater flow of rivers or drinking water utilities, or medical applications where blood carries isotopomers used for communication in a human or animal body. We simulate the capacity of communication in the sense of symbols per second and maximum symbol rate for different applications. We provide estimations for the symbol rate per distance and we demonstrate the feasibility to identify isotopes reliably. In summary, this isotopic molecular communication is a new paradigm for data transfer independent from molecular concentrations and chemical reactions, and can provide higher throughput than ordinary molecular communications.
|||A FPGA-Based Broadband EIT System for Complex Bioimpedance Measurements—Design and Performance Estimation , In Electronics, volume 4, 2015. [bib] [pdf] [abstract]|
Electrical impedance tomography (EIT) is an imaging method that is able to estimate the electrical conductivity distribution of living tissue. This work presents a field programmable gate array (FPGA)-based multi-frequency EIT system for complex, time-resolved bioimpedance measurements. The system has the capability to work with measurement setups with up to 16 current electrodes and 16 voltage electrodes. The excitation current has a range of about 10 µA to 5 mA, whereas the sinusoidal signal used for excitation can have a frequency of up to 500 kHz. Additionally, the usage of a chirp or rectangular signal excitation is possible. Furthermore, the described system has a sample rate of up to 3480 impedance spectra per second (ISPS). The performance of the EIT system is demonstrated with a resistor-based phantom and tank phantoms. Additionally, first measurements taken from the human thorax during a breathing cycle are presented.
|||A high accuracy broadband measurement system for time resolved complex bioimpedance measurements , In Physiological Measurement, volume 35, 2014. [bib] [pdf] [abstract]|
Bioimpedance measurements are useful tools in biomedical engineering and life science. Bioimpedance is the electrical impedance of living tissue and can be used in the analysis of various physiological parameters. Bioimpedance is commonly measured by injecting a small well known alternating current via surface electrodes into an object under test and measuring the resultant surface voltages. It is non-invasive, painless and has no known hazards. This work presents a field programmable gate array based high accuracy broadband bioimpedance measurement system for time resolved bioimpedance measurements. The system is able to measure magnitude and phase of complex impedances under test in a frequency range of about 10–500 kHz with excitation currents from 10 µA to 5 mA. The overall measurement uncertainties stay below 1% for the impedance magnitude and below 0.5° for the phase in most measurement ranges. Furthermore, the described system has a sample rate of up to 3840 impedance spectra per second. The performance of the bioimpedance measurement system is demonstrated with a resistor based system calibration and with measurements on biological samples.
|||Measurements of Electrode Skin Impedances using Carbon Rubber Electrodes – First Results , In Journal of Physics: Conference Series, volume 434, 2013. [bib] [pdf] [abstract]|
Non-invasive bioimpedance measurement as a tool in biomedical engineering and life sciences allows conclusions about condition and composition of living tissue. For interfacing the electronic conduction of the instrumentation and the ionic conduction of the tissue, electrodes are needed. A crucial point is the uncertainty arising from the unknown, time-varying and current density depend Electrode Skin Impedance (ESI). This work presents ESI measurements using carbon rubber electrodes on different human test subjects. The measurements for this work are carried out by employing a high accuracy Bioimpedance Measurement System (BMS) developed by the authors group, which is based on a Field Programmable Gate Array (FPGA) System on Chip (SoC). The system is able to measure magnitude and phase of complex impedances using a two- or four-electrode setup, with excitation currents from 60 μA to 5 mA in a frequency range from about 10 kHz to 300 kHz. Achieved overall measurement uncertainties are below 1%.
Refereed Conference Papers
|||Development of an Electro Impedance Tomography-based Platform for Measurement of burial Depth of Cables in Subsea Sediments , In Oceans 2019, 2019. [bib] [abstract]|
Cables buried in the seabed are objects of interests especially as companies have to verify that the buried depth of the cables is in the expected range, typically $1~m$. Although several measurement systems have been designed in the past, there is no solution available that provides an accuracy of $pm10~cm$ for this purpose. In our approach we suggest to model and measure the electrical field and electrical impedance to determine the depth of a sea cable. In the first step we develop an electrical static field model for analytic investigations. We validate the model by a simulation tool and provide results for critical environmental parameters that affect our measurement accuracy.
|||Autonome Unterwasserfahrzeuge und Kommunikationssysteme , In MST 2018 - Multisensortechnologie: Low-Cost Sensoren im Verbund Deutsche Hydrographische Gesellschaft, volume 92, 2018. [bib] [pdf] [abstract]|
Jedes moderne geodätische Messinstrument ist ein Multisensorsystem, nicht jedes kann aber als Low-Cost System bezeichnet werden. Dieser Band bietet einen Überblick zu Multisensorsystemen, Beiträge zu mathematischen Modellen zur Sensorfusion sowie zu Kommunikations-, Kalibrier- und Synchronisationsaspekten. Klassische Anwendungen wie Gleisaufnahme, Straßenerfassung sowie Überwachungsaufgaben werden beschrieben. Weitere Anwendungen finden Unterwasser, bei Verkehrsbetrieben und in der kinematischen Ingenieurvermessung statt. Ein Schwerpunkt liegt auf der Positionsbestimmung für Fußgänger und Fahrzeuge.
|||Unterwasserkommunikation, Systemvernetzung & autonome Kommunikation im Projekt BOSS , In Hydrographie 2018 - Trend zu unbemannten Messsystemen Deutsche Hydrographische Gesellschaft, volume 91, 2018. [bib] [pdf] [abstract]|
Mit unbemannten hydrographischen Erfassungssystemen, die meist ferngesteuert, zum Teil autonom oder im Verbund arbeiten, werden neue Anwendungsfelder erschlossen. Es stellt sich die Frage: Wie anwendungsreif und wirtschaftlich sind unbemannte Systeme und wie wirkt sich dies auf das Leistungsspektrum der Hydrographie aus? Dieser Band vermittelt Grundlagen zu Datenerfassungsmethoden mit integrierten Multisensorsystemen und gibt einen aktuellen Überblick über Anwendungen im Binnenbereich sowie Projekte im Hochsee- und Küstenbereich. Der Stand der Technik und die neuesten Entwicklungen werden vorgestellt.
|||Wireless Underwater Communication via Analog OFDM Modulated Light , In Proceedings of the International Conference on Underwater Networks & Systems ACM, 2017. [bib] [pdf] [abstract]|
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. This solution increases robustness, flexibility, and range. Furthermore, it decreases power requirements. Even with up to a 30 degree angular displacement of the transmitter the system works very well at a 6 m distance, and with a moderate power consumption of 7 W.
|||A Flexible and Modular Platform for Development of Short-range Underwater Communication , In Proceedings of the 11th ACM International Conference on Underwater Networks & Systems ACM, 2016. [bib] [pdf] [abstract]|
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 only usable for a single development phase or a single wireless technology. Furthermore, the modification and adaption between the phases and technologies are costly and time-consuming. Platforms providing the flexibility to switch between phases or even wireless technologies are either expensive or are not suitable to be integrated into underwater equipment. We developed a flexible and modular platform consisting of a controller and different front ends. The platform is capable of performing complex tasks during all development phases. To achieve high performance with more complex modulation schemes, we combine an embedded Linux processor with a field programmable gate array (FPGA) for computational demanding tasks. We show that our platform is capable of supporting the development of short-range underwater communication systems using a variety of wireless underwater communication technologies.
|||Underwater Electric Field Communication , In Proceedings of the International Conference on Underwater Networks & Systems ACM, 2014. [bib] [pdf] [abstract]|
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 frequency band offers high data rates but due to extreme attenuation the range is limited to less than one meter. Therefore, we suggest to set up an electrical field by two electrodes forming a dipole for transmission and reception in the MF Band (medium frequency band between 100 kHz and 10 MHz). Analytic calculations and simulations verify the concept. In the second step, we measure the transmission channel with different transmitter and receiver geometries. We show that the achievable transmission range of our approach is scalable with the separation distance between the electrodes. In a first practical evaluation with software defined radios we realized a communication link with digital modulation and a data rate of two megabit per second with signal frequency of 2 MHz for several meters.
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