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The invention relates to a method for determining properties of a pipeline, more particularly the position of a branch in a waste water pipeline, in which: a sound wave transmission signal (S, S') is fed into the pipeline (1) at a predetermined infeed point and propagates in the axial direction of the pipeline (1), wherein the frequency spectrum of the sound wave transmission signal (S, S') has a frequency component or a spectral range, the maximum frequency of which is lower than the lower limit frequency (fc) for the first upper mode; in which method components (Sr1, Sr2, Sr3, S'r1, S'r2, S'r3) of the sound wave transmission signal (S, S') reflected inside the pipeline (1) are detected as a sound wave reception signal (E, E'); and in which method, by evaluating the sound wave reception signal (E, E') in relation to the sound wave transmission signal (S, S'), the pipeline (1) is examined for the presence of reflection sites along the pipeline (1) that cause sound wave reflections (Sr1, Sr2, Sr3, S'r1, S'r2, S'r3), wherein at least the distance (I) of a reflection site from the infeed point is determined by evaluating the respective sound wave reception signal (E, E'). The invention further relates to a device for implementing said method.
This paper describes the magmaOffenburg 3D simulation team trying to qualify for RoboCup 2013. While last year’s TDP focused on different ways how robot behavior can be defined in the magmaOffenburg framework this year we focus on how we statistically evaluate new features on distributed systems. We also show some results gained through such analysis.
Die Erfindung betrifft ein Verfahren zur Bestimmung von Eigenschaften einer Rohrleitung, insbesondere der Position eines Abzweigs einer Abwasserrohrleitung, bei dem ein Schallwellensendesignal (S, S‘) an einem vorgegebenen Einspeisepunkt in die Rohrleitung (1) eingespeist wird und sich in axialer Richtung der Rohrleitung (1) ausbreitet, wobei das Frequenzspektrum des Schallwellensendesignals (S, S‘) eine Frequenzkomponente oder einen Spektralbereich aufweist, dessen maximale Frequenz kleiner ist als die untere Grenzfrequenz (fc) für die erste Obermode, bei dem innerhalb der Rohrleitung (1) reflektierte Anteile (Sr1, Sr2, Sr3, S’r1, S’r2, S’r3) des Schallwellensendesignals (S, S‘) als Schallwellenempfangssignal (E, E‘) detektiert werden, und bei dem die Rohrleitung (1) durch eine Auswertung des Schallwellenempfangssignals (E, E‘) in Bezug auf das Schallwellensendesignal (S, S‘) hinsichtlich des Vorhandenseins von Schallwellenreflexionen (Sr1, Sr2, Sr3, S’r1, S’r2, S’r3) verursachenden Reflexionsorten entlang der Rohrleitung (1) untersucht wird, wobei mittels der Auswertung des Schallwellenempfangssignals (E, E‘) zumindest jeweils der Abstand (l) eines Reflexionsortes von dem Einspeisepunkt bestimmt wird. Des Weiteren betrifft die Erfindung eine Vorrichtung zur Realisierung des Verfahrens.
In the brain-cell microenvironment, diffusion plays an important role: apart from delivering glucose and oxygen from the vascular system to brain cells, it also moves informational substances between cells. The brain is an extremely complex structure of interwoven, intercommunicating cells, but recent theoretical and experimental works showed that the classical laws of diffusion, cast in the framework of porous media theory, can deliver an accurate quantitative description of the way molecules are transported through this tissue. The mathematical modeling and the numerical simulations are successfully applied in the investigation of diffusion processes in tissues, replacing the costly laboratory investigations. Nevertheless, modeling must rely on highly accurate information regarding the main parameters (tortuosity, volume fraction) which characterize the tissue, obtained by structural and functional imaging. The usual techniques to measure the diffusion mechanism in brain tissue are the radiotracer method, the real time iontophoretic method and integrative optical imaging using fluorescence microscopy. A promising technique for obtaining the values for characteristic parameters of the transport equation is the direct optical investigation using optical fibers. The analysis of these parameters also reveals how the local geometry of the brain changes with time or under pathological conditions. This paper presents a set of computations concerning the mass transport inside the brain tissue, for different types of cells. By measuring the time evolution of the concentration profile of an injected substance and using suitable fitting procedures, the main parameters characterizing the tissue can be determined. This type of analysis could be an important tool in understanding the functional mechanisms of effective drug delivery in complex structures such as the brain tissue. It also offers possibilities to realize optical imaging methods for in vitro and in vivo measurements using optical fibers. The model also may help in radiotracer biomarker models for the understanding of the mechanism of action of new chemical entities.
A highly scalable IEEE802.11p communication and localization subsystem for autonomous urban driving
(2013)
The IEEE802.11p standard describes a protocol for car-to-X and mainly for car-to-car-communication. It has found its place in hardware and firmware implementations and is currently tested in various field tests. In the research project Ko-TAG, which is part of the research initiative Ko-FAS, cooperative sensor technology is developed for the support of highly autonomous driving. A secondary radar principle based on communication signals enables localization of objects with simultaneous data transmission. It mainly concentrates on the detection of pedestrians and other vulnerable road users (VRU), but also supports pre crash safety applications. Thus it is mainly targeted for the support of traffic safety applications in intra-urban scenarios. This contribution describes the Ko-TAG part of the overall initiative, which develops a subsystem to improve the real-time characteristics of IEEE802.11p needed for precise time of flight real-time localization. In doing this, it still fits into the regulatory schemes. It discusses the approach for definition and verification of the protocol design, while maintaining the close coexistence with existing IEEE802.11p subsystems. System simulations were performed and hardware was implemented. Test results are shown in the last part of the paper.
A Localization System Using Inertial Measurement Units from Wireless Commercial Handheld Devices
(2013)
This paper describes a newly developed technology for the calculation of trajectories of mobile objects, which is based on commercially available sensors being integrated into modern mobile phones and other gadgets. First, a step counting technique was implemented. Second, a novel step length estimator is proposed. These two algorithms utilize the data from accelerometer sensor only. Third, the heading information was obtained using a gyroscope with complementary filter in quaternion form. The combined algorithm was implemented on a low-power ARM processor to provide the trajectory points relative to an initial point. The proposed technique was tested by 10 subjects, in different shoes with different paces. The dependence of the performance of the technology on the attaching point of the mobile device is weak. The proposed algorithms have better balance and estimation accuracy and depend in less degree on the variety in physical parameters of people in comparison with the existing techniques. In experiments inertial measurement units were mounted in different places, i.e. in the hand, in trousers or in T-shirt pockets. The return position error did not exceed 5% of the total travelled distance for all performed tests.
The communication technologies for automatic meter reading (smart metering) and for energy production and distribution networks (smart grid) have the potential to be one of the first really highly scaled machine-to-machine-M2M-applications. During the last years, two very promising developments around the wireless part of the smart grid communication were initialized, which possibly could have an impact on the network architectures and the markets far beyond Germany and far beyond energy automation. Besides the specification of the OMS Group of a security extension to the Wireless M-Bus protocol (EN13757-4), the German Federal Office for Information Security (Bundesamt für Sicherheit in der Informationstechnik, BSI) has designed a Protection Profile (PP) and a Technical Directive (TR) for the communication unit of an intelligent measurement system (Smart Meter Gateway), which were released in March 2013. This design uses state of the art technologies and prescribes their implementation in real-life systems. At first, the proposed paper will present the most important characteristics of this architecture. It will then give an insight into the implementation of the OMS security protocols, which imply the usage of a mutually authenticated SSL protocol also in the Local Metrological Network. This is achieved with the help of an additional Authentication and Fragmentation Layer (AFL). This secure communication will be terminated in a BSI conformant secure smart meter gateway, which is developed in a different project and described in the second step. Finally, the contribution will discuss the integration of such a metering network into an overall telecommunication network and PKI infrastructure.
Efficient, low-cost, secure and reliable communication solutions are a major stepping stone for smart metering and smart grid applications. This especially holds true for the so called primary communication or local metrological network (LMN) between a local meter or actuator and a data collector or gateway, where the highest requirements with regard to cost, bandwidth, and energy efficiency have to be taken into consideration. Multiple developments and field tests are going on in this field, however, energy autarkic devices are hardly found, yet. This contribution describes the development of an automatic water meter reading (AWMR) technology based on Wireless M-Bus to provide water utility companies with an automatic remote water meter reading solution. It addresses the special needs of home utilities by providing a remote metering solution independent from the electricity infrastructure, both in terms of data communication and in terms of power supply. For this project, a cost efficient integrated energy harvesting system powered by the available water flow was developed, to enable operation independently of the mains grid, and eliminate the need for battery replacement for near-zero maintenance costs.
The communication technologies for automatic me-ter reading (smart metering) and for energy production and distribution networks (smart grid) have the potential to be one of the first really highly scaled machine-to-machine-(M2M)-applications. During the last years two very promising devel-opments around the wireless part of smart grid communication were initialized, which possibly have an impact on the markets far beyond Europe and far beyond energy automation. Besides the specifications of the Open Metering System (OMS) Group, the German Federal Office for Information Security (Bundesamt für Sicherheit in der Informationstechnik, BSI) has designed a protection profile (PP) and a technical directive (TR) for the communication unit of an intelligent measurement sys-tem (smart meter gateway), which were released in March 2013. This design uses state-of-the-art technologies and prescribes their implementation in real-life systems. At first sight the expenditures for the prescribed solutions seem to be significant. But in the long run, this path is inevitable and comes with strategic advantages.
Die “Selbstbetrachtungen” des Marc Aurel – medizinisch-ethische Betrachtungen des Menschseins
(2013)
The combination of fossil-derived fuels with ethanol and methanol has acquired relevance and attention in several countries in recent years. This trend is strongly affected by market prices, constant geopolitical events, new sustainability policies, new laws and regulations, etc. Besides bio-fuels these materials also include different additives as anti-shock agents and as octane enhancer. Some of the chemical compounds in these additives may have harmful properties for both environment and public health (besides the inherent properties, like volatility). We present detailed Raman spectral information from toluene (C7H8) and ethanol (C2H6O) contained in samples of ElO gasoline-ethanol blends. The spectral information has been extracted by using a robust, high resolution Fourier-Transform Raman spectrometer (FT-Raman) prototype. This spectral information has been also compared with Raman spectra from pure additives and with standard Raman lines in order to validate its accuracy in frequency. The spectral information is presented in the range of 0 cm-1 to 3500 cm-1 with a resolution of 1.66cm-1. This allows resolving tight adjacent Raman lines like the ones observed around 1003cm-1 and 1030cm-1 (characteristic lines of toluene). The Raman spectra obtained show a reduced frequency deviation when compared to standard Raman spectra from different calibration materials. The FT-Raman spectrometer prototype used for the analysis consist basically of a Michelson interferometer and a self-designed photon counter cooled down on a Peltier element arrangement. The light coupling is achieved with conventional62.5/125μm multi-mode fibers. This FT-Raman setup is able to extract high resolution and frequency precise Raman spectra from the additives in the fuels analyzed. The proposed prototype has no additional complex hardware components or costly software modules. The mechanical and thermal disturbances affecting the FT-Raman system are mathematically compensated by accurately extracting the optical path information of the Michelson interferometer. This is accomplished by generating an additional interference pattern with a λ = 632.8 nm Helium-Neon laser (HeNe laser). It enables the FT-Raman system to perform reliable and clean spectral measurements from the materials under observation.
Efficient, low-cost, secure and reliable communication solutions are a major stepping stone for smart metering and smart grid applications. This especially holds true for the so called primary communication or local metrological network (LMN) between a local meter or actuator and a data collector or gateway, where the highest requirements with regard to cost, bandwidth, and energy efficiency have to be taken into consideration. Multiple developments and field tests are going on in this field, however, energy autarkic devices are hardly found, yet.
Ranging errors are inevitable in all local positioning systems, including those based on Time-of-Flight (ToF) technique. Results of experiments show that the major cause for these errors is a signal degradation from multipath propagation. This effect is especially critical in case of Non-Light-of-Sight (NLOS) conditions. This paper describes causes that affects ranging errors for nanoLOC™-TOF-technology and presents estimations for the probability density functions of such errors under different NLOS conditions. The provided estimations allow the improvement of the accuracy of the localization through the subsequent mitigation of the ranging errors from the measurements. Additionally, it is proposed to increase the number of cases of NLOS-conditions for the improvement of the accuracy.
Automatic Meter Reading (AMR) is a major enabler for the upcoming smart grid. Potentially, it will be one of the first really large-scale M2M-communication solutions for sensor applications.
To date, the definition of the standardized communication stacks for Local Metrological Network (LMN) in AMR is still ongoing. This holds true both for ZigBee Smart Energy Profile and for Wireless M-Bus according to EN 13757. During this process, there is the necessity for flexible, albeit optimized solutions, which support the different existing and upcoming versions of the communication protocols. In the case of Wireless M-Bus, the major contender for European and possibly Asian installations, this is valid not only for the different operation modes (C-, N-, P-, Q-, R-, S-, and T-modes), which work in different frequencies (i.e. 868 MHz, 433 MHz, and 169 MHz) but also for the application layer, where additional bodies, like EN137575, Open Metering System (OMS) Group, or national bodies follow their approaches.
This contribution describes requirements, design techniques and experiences from the development of highly efficient Wireless M-Bus protocol stacks with support of good flexibility and portability between microcontroller platforms and RF-transceivers. The presented approach is not limited to the use of modern software engineering design processes, as such, but also includes essential additional features like testing or simulation, as well as tools for commissioning and monitoring.
Die Energiewende ist ein elementares Thema, für Deutschland wie auch für viele andere Regionen weltweit. Bei der Bereitstellung effizienter und stabiler Verteilnetze stellen Kommunikationslösungen einen zentralen Baustein dar, um auf der Grundlage eines zeitnahen Monitorings koordinierte Regelalgorithmen zu realisieren. Dies gilt für alle Ebenen der Versorgung, wobei aus Sicht der Kommunikationstechnik die unterste Ebene der Verteilnetze am interessantesten ist: Hier sind die anspruchsvollsten Anforderungen im Hinblick auf die Kosten- und die Energieoptimierung der Kommunikationsknoten sowie die Administrierbarkeit, die Stabilität und die Skalierbarkeit der Gesamtlösung zu berücksichtigen. Das Steinbeis-Transferzentrum Embedded Design und Networking an der Hochschule Offenburg unter der Leitung von Prof. Dr.-Ing. Axel Sikora hat in verschiedenen Projekten mit renommierten Partnern umfangreiche Lösungen für diese sogenannte Primärkommunikation entwickelt.
Android is an operating system which was developed for use in smart mobile phones and is the current leader in this market. A lot of efforts are being spent to make Android available to the embedded world, as well. Many embedded systems do not have a local GUI and are therefore called headless devices. This paper presents the results of an analysis of the general suitability of Anroid in headless embedded systems and ponders the advantages and disadvantages. It focuses on the hardware related issues, i.e. to what extent Android supports hardware peripherals normally used in embedded systems.
In this paper we propose a motion framework forbipedal robots that decouples motion definitions from stabilizingthe robot. This simplifies motion definitions yet allows dynamicmotion adaptations. Two applications, walking and stopping onone leg, demonstrate the power of the framework. We show thatour framework is able to perform walking and stopping on one legeven under extreme conditions and improves walking benchmarkssignificantly in the RoboCup 3D soccer simulation domain.
Autonomous humanoid robots need high torque actuators to be able to walk and run. One problem in this context is the heat generated. In this paper we propose to use water evaporation to improve cooling of the motors. Simulations based on thermodynamic calculations as well as measurements on real actuators show that, under the assumption of the load of a soccer game, cooling can be considerably improved with relatively small amounts of water.
The formation of secondary phases in the porous electrodes is a severe mechanism affecting the lifetime of solid oxide fuel cells (SOFC). It can occur via various chemical mechanisms and it has a significant influence on cell performance due to pore clogging and deactivation of active surfaces and triple-phase boundary (TPB). We present a modeling and simulation study of nickel oxide formation (reoxidation) and carbon formation (coking) within the SOFC anode. We use a 2D continuum model based on a multi-phase framework [Neidhardt et al., J. Electrochem. Soc., 159, 9 (2012)] that allows the introduction of arbitrary solid phases (here: Ni, YSZ, NiO, Carbon) plus gas phase. Reactions between the bulk phases are modeled via interface-adsorbed species and are described by an elementary kinetic approach. Published experimental data are used for parameterization and validation. Simulations allow the prediction of cell performance under critical operation conditions, like (i) a non-fuel operation test, where NiO formation is taking place (Figure 1a), or (ii) an open circuit voltage (OCV) stability test under hydrocarbon atmosphere, where solid carbon is formed (Figure 1b). Results are applied for enhanced interpretation of experimental data and for prediction of safe operation conditions.
The communication between objects, i.e. between cars (car-2-car, C2C), between cars and infrastructure (car-2-infrastructure, C2I) and between cars and vulnerable road users (car-2-VRU, C2VRU) is a major stepping stone towards traffic applications to enable efficient and safe traffic flow. However, these applications pose very high requirements to the communication protocols, which go beyond the capabilities of an available standardized solution.
This contribution shows how iterative design processes can help to fulfill these requirements, while re-using a maximum of elements from one level to the next and thus avoiding unrealistic overhead. In especially, the added value of simulation and emulation in this iterative process is elaborated.
The IEEE802.11p standard describes a protocol for car-to-X and mainly for car-to-car-communication. It has found its place in hardware and firmware implementations and is currently tested in various field tests. In the research project Ko-TAG, which is part of the research initiative Ko-FAS, cooperative sensor technology is developed and its benefit for traffic safety applications is evaluated. A secondary radar principle based on communication signals enables localization of objects with simultaneous data transmission. It mainly concentrates on the detection of pedestrians and other vulnerable road users (VRU), but also supports pre crash safety applications. The Ko-TAG proposal enriches the current IEEE802.11p real-time characteristics needed for precise time-of-flight real-time localization. This contribution describes the development of a subsystem, which extends the functionality of IEEE802.11p and fits into the regulatory schemes. It discusses the approach for definition and verification of the protocol design, while maintaining the close coexistence with existing IEEE802.11p subsystems. System simulations were performed and hardware was implemented. The next step will be field measurements to verify the simulation results.
The lifetime and performance of solid-oxide fuel cells (SOFC) and electrolyzer cells (SOEC) can be significantly degraded by oxidation of nickel within the electrode and support structures. This paper documents a detailed computational model describing nickel oxide (NiO) formation as a growing film layer on top of the nickel phase in Ni/YSZ composite electrodes. The model assumes that the oxidation rate is controlled by transport of ions across the film (Wagner's theory). The computational model, which is implemented in a two-dimensional continuum framework, facilitates the investigation of alternative chemical reaction and transport mechanisms. Model predictions agree well with a literature experimental measurement of oxidation-layer growth. In addition to providing insight in interpreting experimental observations, the model provides a quantitative predictive capability for improving electrode design and controlling operating conditions.
In the dual membrane fuel cell (DM-Cell), protons formed at the anode and oxygen ions formed at the cathode migrate through their respective dense electrolytes to react and form water in a porous composite layer called dual membrane (DM). The DM-Cell concept was experimentally proven (as detailed in Part I of this paper). To describe the electrochemical processes occurring in this novel fuel cell, a mathematical model has been developed which focuses on the DM as the characteristic feature of the DM-Cell. In the model, the porous composite DM is treated as a continuum medium characterized by effective macro-homogeneous properties. To simulate the polarization behavior of the DM-Cell, the potential distribution in the DM is related to the flux of protons and oxygen ions in the conducting phases by introducing kinetic and transport equations into charge balances. Since water pressure may affect the overall formation rate, water mass balances across the DM and transport equations are also considered. The satisfactory comparison with available experimental results suggests that the model provides sound indications on the effects of key design parameters and operating conditions on cell behavior and performance.
Modeling and Simulation the Influence of Solid Carbon Formation on SOFC Performance and Degradation
(2013)
In this paper we present a model of the discharge of a lithium–oxygen battery with aqueous electrolyte. Lithium–oxygen batteries (Li–O2) have recently received great attention due to their large theoretical specific energy. Advantages of the aqueous design include the stability of the electrolyte, the long experience with gas diffusion electrodes (GDEs), and the solubility of the reaction product lithium hydroxide. However, competitive specific energies can only be obtained if the product is allowed to precipitate. Here we present a dynamic one-dimensional model of a Li–O2 battery including a GDE and precipitation of lithium hydroxide. The model is parameterized using experimental data from the literature. We demonstrate that GDEs remove power limitations due to slow oxygen transport in solutions and that lithium hydroxide tends to precipitate on the anode side. We discuss the system architecture to engineer where nucleation and growth predominantly occurs and to optimize for discharge capacity.