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Lernziele:
Die Leser
• kennen die Bestandteile und Aufgaben der Produktion;
• wissen, welche Ansätze die Vision einer 100 % nachhaltigen Produktion hinsichtlich Material- und Energieverwendung beinhalten;
• verfügen über den Einblick, welche Stufen auf dem Weg zur nachhaltigen Produktion zu nehmen sind;
• wissen auch anhand von Beispielen, welche Ansätze zur Umsetzung einer nachhaltigen Produktion bestehen;
• kennen im Überblick die Ansätze zur Messung von Nachhaltigkeit in der Produktion.
Grundlagen der Organisation
(2019)
Eine betriebswirtschaftliche Theorie der Organisationsgestaltung hat Strukturmodelle zu entwickeln, die als Grundlage für Organisationsentscheidungen des Managements geeignet sind. Es geht dabei um die Bewältigung der elementaren Anforderungen, die bei interpersoneller Arbeitsteilung zwangsläufig durch die Trennung zusammenhängender Aufgabenkomplexe und die Einbeziehung einer Mehrzahl von Personen mit jeweils individuellen Zielen entstehen. Bei der Verfolgung dieses Anliegens orientiert sich auch die Neuauflage der "Grundlagen der Organisation" unverändert am bewährten entscheidungstheoretischen Konzept der Organisationsgestaltung, das einen fundierten anwendungsbezogen Zugang zum Verständnis und zur Lösung komplexer Organisationsprobleme eröffnet.
Automobile premium brands operate globally, which is undoubtedly required, because, for the most part, domestic markets are either decreasing or stagnating. China has become today the most important and biggest car market. Recently selling has become challenging because urban areas are well penetrated, and in poorly penetrated rural areas, incomes are low. This is particularly alarming for German brands, because of their premium orientation. Simultaneously, the after-sales market in China has been growing continuously. As a result, this market has a huge potential, which is likewise attractive because it has been scientifically proven across industries that after-sales services are high-margin profit drivers. Despite its great significance, the Chinese automobile after-sales market remains insufficiently researched, especially in terms of critical success factors and cultural influences, which therefore was the starting point for a study. The results will presented and interpreted now in this new working-paper.
In the last years, social robots have become a trending topic. Indeed, robots which communicate with us and mimic human behavior patterns are fascinating. However, while there is a massive body of research on their design and acceptance in different fields of application, their market potential has been rarely investigated. As their future integration in society may have a vast disruptive potential, this work aims at shedding light on the market potential, focusing on the assistive health domain. A study with 197 persons from Italy (age: M = 67.87; SD = 8.87) and Germany (age: M = 62.15; SD = 6.14) investigates cultural acceptance, desired functionalities, and purchase preferences. The participants filled in a questionnaire after watching a video illustrating some examples of social robots. Surprisingly, the individual perception of health status, social status as well as nationality did hardly influence the attitude towards social robots, although the German group was somewhat more reluctant to the idea of using them. Instead, there were significant correlations with most dimensions of the Almere model (like perceived enjoyment, sociability, usefulness and trustworthiness). Also, technology acceptance resulted strongly correlated with the individual readiness to invest money. However, as most persons consider social robots as “Assistive Technological Devices” (ATDs), they expected that their provision should mirror the usual practices followed in the two Countries for such devices. Thus, to facilitate social robots’ future visibility and adoption by both individuals and health care organisations, policy makers would need to start integrating them into official ATDs databases.
In this work the nonlinear behavior of layered surface acoustic wave (SAW) resonators is studied with the help of finite element (FE) computations. The full calculations depend strongly on the availability of accurate tensor data. While there are accurate material data for linear computations, the complete sets of higher-order material constants, needed for nonlinear simulations, are still not available for relevant materials. To overcome this problem, scaling factors were used for each available nonlinear tensor. The approach here considers piezoelectricity, dielectricity, electrostriction, and elasticity constants up to the fourth order. These factors act as a phenomenological estimate for incomplete tensor data. Since no set of fourth-order material constants for LiTaO3 is available, an isotropic approximation for the fourth-order elastic constants was applied. As a result, it was found that the fourth-order elastic tensor is dominated by one-fourth order Lamé constant. With the help of the FE model, derived in two different, but equivalent ways, we investigate the nonlinear behavior of a SAW resonator with a layered material stack. The focus was set to third-order nonlinearity. Accordingly, the modeling approach is validated using measurements of third-order effects in test resonators. In addition, the acoustic field distribution is analyzed.
This work focuses on the dependencies between typical design parameters of surface acoustic wave (SAW) resonators and the nonlinear emitted signals of second and third order. The parameters metalization ratio and pitch are used as examples, but the approach can be extended to other design parameters as well. It is shown, that the interaction between the nonlinear current generation and the linear admittance is defining the measured nonlinear power signals. It is also discussed, that changes in linear properties get more pronounced in nonlinear responses. Therefore, slight effects on linear parameters will have significant influence on the observed nonlinearity.
Increasing power density causes increased self-generation of harmonics and intermodulation. As this leads to violations of the strict linearity requirements, especially for carrier aggregation (CA), the nonlinearity must be considered in the design process of RF devices. This raises the demand of accurate simulation models. Linear and nonlinear P-Matrix/COM models are used during the design due to their fast simulation times and accurate results. However, the finite element method (FEM) is useful to get a deeper insight in the device's nonlinearities, as the total field distributions can be visualized. The FE method requires complete sets of material tensors, which are unknown for most relevant materials in nonlinear micro-acoustics. In this work, we perform nonlinear FEM simulations, which allow the calculation of nonlinear field distributions of a lithium tantalate based layered SAW system up to third order. We aim at achieving good correspondence to measured data and determine the contributions of each material layer to the nonlinear signals. Therefore, we use approximations circumventing the issue of limited higher order tensor data. Experimental data for the third order nonlinearity is shown to validate the presented approach.
Erfolgsfaktorenforschung
(2018)
Kostenrechnung
(2015)
Running stability is the ability to withstand naturally occurring minor perturbations during running. It is susceptible to external and internal running conditions such as footwear or fatigue. However, both its reliable measurability and the extent to which laboratory measurements reflect outdoor running remain unclear. This study aimed to evaluate the intra- and inter-day reliability of the running stability as well as the comparability of different laboratory and outdoor conditions. Competitive runners completed runs on a motorized treadmill in a research laboratory and overground both indoors and outdoors. Running stability was determined as the maximum short-term divergence exponent from the raw gyroscope signals of wearable sensors mounted to four different body locations (sternum, sacrum, tibia, and foot). Sacrum sensor measurements demonstrated the highest reliabilities (good to excellent; ICC = 0.85 to 0.91), while those of the tibia measurements showed the lowest (moderate to good; ICC = 0.55 to 0.89). Treadmill measurements depicted systematically lower values than both overground conditions for all sensor locations (relative bias = -9.8% to -2.9%). The two overground conditions, however, showed high agreement (relative bias = -0.3% to 0.5%; relative limits of agreement = 9.2% to 15.4%). Our results imply moderate to excellent reliability for both overground and treadmill running, which is the foundation of further research on running stability.
Für langfaserverstärkte Thermoplaste (LFT) wird ein repräsentatives Volumenelement (RVE) für FEM-Simulationen generiert. Dies geschieht unter Berücksichtigung von mikrostrukturellen Kenngrößen wie Faserorientierungsverteilung, -volumengehalt und -längenverteilung, die für einen charakteristischen Werkstoffzustand experimentell ermittelt wurden. Mittels Mikrostruktursimulationen wird das Kriechverhalten von LFT untersucht. Das viskoelastische Verhalten der Matrix wird experimentell an Substanzproben aus Polypropylen ermittelt und in die RVE-Simulationen mit einem modifizierten Burgers-Modell implementiert. Schließlich werden die Rechnungen mit verschiedenen, fiktiven sowie experimentell ermittelten Faserlängenverteilungen mit Kriechversuchen am LFT verglichen. Es zeigt sich eine starke Abhängigkeit des Kriechverhaltens von der Faserlänge und eine hohe Prognosegüte der Simulationen, die die experimentell ermittelte Längenverteilung berücksichtigen.
Das Team „Schluckspecht“ stellte sich im September 2010 einer besonderen Herausforderung. Neben der jährlichen Teilnahme am Shell Eco-Marathon ging das Team mit einem neu entwickelten Elektrofahrzeug an den Start der South Africa Solar Challenge. Für die Nutzung von Akkumulatoren als Energielieferant im Leichtfahrzeug „Schluckspecht E“ (im weiteren Verlauf als Batterien bezeichnet) wurde ein neues Strukturkonzept in Zusammenarbeit der Hochschule Offenburg mit dem Fraunhofer-Institut für Kurzzeitdynamik, Ernst-Mach-Institut, EMI entwickelt.
In the year 2009 several data privacy scandals have hit the headlines where major corporations had a legitimate need for detecting fraud conducted by their own employees, but chose inappropriate measures for data screening. This contribution presents architectures and pseudonymization technology for privacy compliant fraud screening or fraud detection, in order to reduce the number of undiscovered fraud cases and to reduce the time to discovery.
Considering the literature for aqueous rechargeable Zn//MnO2 batteries with acidic electrolytes using the doctor blade coating of the active material (AM), carbon black (CB), and binder polymer (BP) for the positive electrode fabrication, different binder types with (non-)aqueous solvents were introduced so far. Furthermore, in most of the cases, relatively high passive material (CB+BP) shares ~30 wt% were applied. The first part of this work focuses on different selected BPs: polyacrylonitrile (PAN), carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), cellulose acetate (CA), and nitrile butadiene rubber (NBR). They were used together with (non-)aqueous solvents: DI-water, methyl ethyl ketone (MEK), and dimethyl sulfoxide (DMSO). By performing mechanical, electrochemical and optical characterizations, a better overall performance of the BPs using aqueous solvents was found in aqueous 2 M ZnSO4 + 0.1 M MnSO4 electrolyte (i.e., BP LA133: 150 mAh·g−1 and 189 mWh·g−1 @ 160 mA·g−1). The second part focuses on the mixing ratio of the electrode components, aiming at the decrease of the commonly used passive material share of ~30 wt% for an industrial-oriented electrode fabrication, while still maintaining the electrochemical performance. Here, the absolute CB share and the CB/BP ratio are found to be important parameters for an application-oriented electrode fabrication (i.e., high energy/power applications).
Background: Assistive Robotic Arms are designed to assist physically disabled people with daily activities. Existing joysticks and head controls are not applicable for severely disabled people such as people with Locked-in Syndrome. Therefore, eye tracking control is part of ongoing research. The related literature spans many disciplines, creating a heterogeneous field that makes it difficult to gain an overview.
Objectives: This work focuses on ARAs that are controlled by gaze and eye movements. By answering the research questions, this paper provides details on the design of the systems, a comparison of input modalities, methods for measuring the performance of these controls, and an outlook on research areas that gained interest in recent years.
Methods: This review was conducted as outlined in the PRISMA 2020 Statement. After identifying a wide range of approaches in use the authors decided to use the PRISMA-ScR extension for a scoping review to present the results. The identification process was carried out by screening three databases. After the screening process, a snowball search was conducted.
Results: 39 articles and 6 reviews were included in this article. Characteristics related to the system and study design were extracted and presented divided into three groups based on the use of eye tracking.
Conclusion: This paper aims to provide an overview for researchers new to the field by offering insight into eye tracking based robot controllers. We have identified open questions that need to be answered in order to provide people with severe motor function loss with systems that are highly useable and accessible.
Das TMKB-Modell beschreibt einen Weg, den persönlichen und unternehmerischen Erfolg im beruflichen Alltag effizient und nachhaltig zu erreichen. Hierbei steht TMKB für den Transfer von Methoden und Kompetenzen in den Beruf. Dieses Modell beachtet die Theorien der Kompetenzentwicklung im Kontext realer Problemstellungen in Unternehmen. Beispielhaft wird das TMKB-Modell in der ersten Stufe mit dem Schwerpunkt Lean- und Projektmanagement erläutert. Die Zielgruppe dieses Ansatzes lässt sich über die der Auszubildenden bis hin zu Studierenden und Berufserfahrenen erweitern.
Digitalisierung ist heute allgegenwärtig. Wo im Privaten bereitwillig neue digitale Tools, Apps und Funktionen genutzt werden, tun sich Unternehmen in der Umsetzung von Digitalisierungsprojekten oft schwer. Dieser Beitrag beleuchtet die Motive für Digitalisierungsvorhaben, ihre Hürden sowie die Auswirkung auf die Arbeitsbelastung von Mitarbeitenden und versucht in der Verknüpfung mit den Grundprinzipien des Kontinuierlichen Verbesserungsprozesses, Handlungsempfehlungen für eine erfolgreiche Umsetzung dieser abzuleiten.
This paper treats the Brillouin backscattering in a single mode optical fiber and its implications on the Brillouin Ring Laser Gyroscope (BRLG). The BRLG consists of a fiber ring cavity in which stimulated Brillouin scattering is induced and provides two resonant counterpropagating backscattered waves. If this cavity is rotating around its axis, the backscattered waves get different resonant frequencies because of the Sagnac effect. The frequency difference is proportional to the rotation rate (Omega) by inducing a frequency offset between the counterpropagating waves. Some reported Brillouin spectra exhibit several peaks, which means that one pump wave provides at least two backscattered waves with distinguishable frequencies. In order to understand this multi-backscattering and to take advantage of it for the BRLG, we present results of a simulation of the Brillouin backscattering in a single mode optical fiber.
This paper treats the interaction between acoustic modes and light (Brillouin scattering) in a single mode optical fibre. Different observed spectra of the Brillouin backscattering in several fibres have been already reported. In order to have a clear idea of the process, we made a simulation to be able to `draw' the theoretical Brillouin spectrum of an optical fibre and to identify the origin of the observed backscattered lines.
First, the model and the computation method used in our simulation are described. Second, the experimentally observed spectra of two real fibres are compared with their computed spectra. Real spectra and simulated spectra are in good agreement.
Our work provides an interesting tool to investigate the changes in the Brillouin spectrum when the input parameters (characteristics of an optical fibre) vary. This should give useful indications to people working on systems which use Brillouin backscattering.
Produkt-Controlling
(2021)
Zentraler Baustein des Marketing ist die „facettenreiche“ Produktpolitik. Im nachstehenden Beitrag wird zunächst die Einordnung der Produktpolitik in den Zielkatalog des Marketing und des Unternehmens skizziert. Das Produkt-Controlling wird verstanden als zielgerichtete Unterstützung der Managementaufgaben im Kontext der Produktpolitik mittels passender Instrumente – Instrumente, die der Phase der Produktentstehung wie der Marktzyklusphase zuzuordnen sind. Erkennbar wird: es gibt ein umfangreiches Set an Methoden, die das Marketing-Management unterstützen und die Sicherstellung der Marketing-Effektivität und Marketing-Effizienz gewährleisten. Die Komplexität des Produkt-Controllings bedingt sich auch durch den ausreichenden Einbezug preis-, qualitäts- und markenpolitischer Informationen in die Zielkontrolle.
Produkt-Controlling
(2017)
Zentraler Baustein des Marketing ist die „facettenreiche“ Produktpolitik. Im nachstehenden Beitrag wird zunächst die Einordnung der Produktpolitik in den Zielkatalog des Marketing und des Unternehmens skizziert. Das Produkt-Controlling wird verstanden als zielgerichtete Unterstützung der Managementaufgaben im Kontext der Produktpolitik mittels passender Instrumente – Instrumente, die der Phase der Produktentstehung wie der Marktzyklusphase zuzuordnen sind. Erkennbar wird: es gibt ein umfangreiches Set an Methoden, die das Marketing-Management unterstützen und die Sicherstellung der Marketing-Effektivität und Marketing-Effizienz gewährleisten. Die Komplexität des Produkt-Controllings bedingt sich auch durch den ausreichenden Einbezug preis-, qualitäts- und markenpolitischer Informationen in die Zielkontrolle.
Kritische Analyse des Geschäftsmodells von Amazon mit einem Fokus auf wettbewerbsrechtliche Aspekte
(2021)
Die Digitalisierung verändert unsere Gesellschaft, sie schafft beinahe unendliche Möglichkeiten und eröffnet neue Wege zur Nutzung von innovativen Ideen. Daraus hervorgegangen sind auch digitale Plattformen, welche heute nicht mehr wegzudenken sind und von nahezu jedem Konsumenten genutzt werden. Während der fortdauernden Coronapandemie haben digitale Plattformen und insbesondere digitale Marktplätze zunehmend an Bedeutung gewonnen, denn während Einzelhändler ihre Geschäfte vor Ort schließen mussten, blieb der Einkauf über digitale Angebote weiterhin möglich. Diesen Bedeutungszuwachs bestätigt auch der Umsatz von Amazon, einem Unternehmen, welches mit seinem digitalen Geschäftsmodell insbesondere für seinen digitalen Marktplatz bekannt ist, denn es verzeichnet im ersten Quartal 2021 ein Umsatzwachstum von 44 Prozent im Vergleich zum Vorjahreszeitraum. Es ist davon auszugehen, dass es sich dabei um eine Entwicklung handelt, welche fortdauern wird, denn das Verhalten von Verbrauchern wird sich durch die Erfahrungen, die sie im Laufe der Pandemie gesammelt haben, nachhaltig verändern. So wollen Menschen beispielsweise auch nach der Pandemie vermehrt online sein und insbesondere auch online einkaufen, da es bequemer und zeitsparender ist und online meist bessere Angebote verfügbar sind.
Ziel dieser Studie ist es, den Markt von FinTech Unternehmen in Deutschland unter Berücksichtigung der beteiligten Marktkräfte darzustellen. Hierfür sollen die theoretischen Grundlagen einer Marktanalyse dargelegt und darauf aufbauend eine Marktanalyse durchgeführt werden. Betrachtet werden sollen in diesem Zusammenhang auch die rechtlichen Rahmenbedingungen, die für FinTech Unternehmen in Deutschland einschlägig sind, da auch diese Einfluss auf das Marktgeschehen haben. Ziel ist es, bestehende Rechtsgrundlagen sowie Entwürfe von künftigen Rechtsvorschriften mittels Recherche zu identifizieren und zu analysieren. Betrachtet werden sollen dabei das deutsche Recht sowie das für Deutschland als Mitgliedstaat der EU geltende EU-Recht.
Learning to Walk With Toes
(2020)
This paper explains how a model-free (with respect to the robot model and the behavior to learn) approach can facilitate learning to walk from scratch. It is applied to a simulated Nao robot with toes. Results show an improvement of 30% in speed compared to a model without toes and also compared to our model-based approach, but with less stability.
Um sicherzustellen, dass vom Unternehmen keine Verstöße gegen gesetzliche Vorschriften und Regeln erfolgen, ist es unabdingbar, dass die Mitarbeiter des Unternehmens den aufgestellten Pflichten nachkommen und diese befolgen. Dabei kann dies nur verwirklicht werden, wenn die Regelungen für die Arbeitnehmer verbindlich werden und bei Fehlverhalten auch arbeitsrechtliche Sanktionen als Konsequenz durchgesetzt werden können. Damit die Verhaltensrichtlinien und -grundsätze für die Arbeitnehmer verbindlich werden, müssen diese arbeitsrechtlich im Unternehmen implementiert werden. Die Implementierung kann dabei grundsätzlich durch unterschiedliche arbeitsrechtliche Instrumente umgesetzt werden, wobei sowohl das Individual- als auch das Kollektivarbeitsrecht verschiedene Optionen anbietet, welche im Folgenden näher erläutert werden.
In sicherheitskritschen Systemen darf kein Stück Code im Produktionsbetrieb ablaufen, ohne vorher intensive Tests durchlaufen zu haben. Aber auch zur Qualitätssicherung muss Software getestet werden. Um die Codeüberdeckung zu prüfen, sind zusätzliche Prüf-Instruktionen im Quellcode erforderlich. Auf kleinen Systemen mit wenig RAM kann sich der Entwickler dann etwas einfallen lassen, damit das funktioniert.
In this paper fatigue crack closure under in-phase and out-of-phase thermomechanical fatigue (TMF) loading is studied using a temperature dependent strip yield model. It is shown that fatigue crack closure is strongly influenced by the phase relation between mechanical loading and temperature, if the temperature difference goes along with a temperature dependence of the yield stress. In order to demonstrate the effect of the temperature dependent yield stress, the influence of in-phase and out-of-phase TMF loading is studied for a polycrystalline nickel-base superalloy. By using a mechanism based lifetime model, implications for fatigue lives are demonstrated.
A crack opening stress equation for in-phase and out-of-phase thermomechanical fatigue loading
(2016)
In this paper, a crack opening stress equation for in-phase and out-of-phase thermomechanical fatigue (TMF) loading is proposed. The equation is derived from systematic calculations of the crack opening stress with a temperature dependent strip yield model for both plane stress and plane strain, different load ratios and different ratios of the temperature dependent yield stress in compression and tension. Using a load ratio scaled by the ratio of the yield stress in compression and tension, the equation accounts for the effect of the temperature dependent yield stress and the constraint on the crack opening stress. Based on the scaling relation established in this paper, Newman's crack opening stress equation for isothermal loading is enabled to predict the crack opening stress under TMF loading.
In the present paper, the influence of locally varying microstructures in case of an AlSi12 cast aluminium alloy is investigated by means of extracting the test pieces from different removal positions and low cycle fatigue tests. The temperature-dependent damage mechanisms, the material specific defect types, sizes and their influence on the fatigue properties of two AlSi7 and AlSi12 cast aluminium alloys are studied. An extreme value statistics methodology is applied to predict maximum defect sizes expected in a critical surface volume from two-dimensional metallographic micrographs. A damage map for the AlSi12 cast aluminium alloy is presented explaining the influence of the temperature- and load-dependent damage mechanisms on the observed isothermal and thermomechanical lifetime behavior.
Detailed material investigations of the fatigue behavior of two cast aluminium alloys used in combustion engines are presented. The network of intermetallic phases of both aluminium alloys is characterized by means of detailed energy dispersive X-ray spectroscopy. In order to investigate the temperature-dependent fatigue behavior of the materials, tensile, low cycle and thermomechanical fatigue tests are performed over a wide temperature and loading range. The influence of the temperature dependence on the experimental results is discussed.
In this work, the influence of superimposed high cycle fatigue on the LCF/HCF and TMF/HCF lifetime is investigated for two cast aluminium alloys of the types AlSi7 and AlSi12. The replica technique is used to examine the short crack growth behavior under pure LCF and LCF/HCF loading. The observed short crack growth evolution explains the observed lifetime reduction with increasing HCF amplitudes.
In this paper, the time- and temperature-dependent cyclic ratchetting plasticity of the nickel-based alloy IN100 is experimentally investigated in strain-controlled experiments in the temperature range from 300 °C to 1050 °C. To this end, uniaxial material tests are performed with complex loading histories designed to activate phenomena as strain rate dependency, stress relaxation as well as the Bauschinger effect, cyclic hardening and softening, ratchetting and recovery from hardening. Plasticity models with different levels of complexity are presented that consider these phenomena, and a strategy is derived to determine the multitude of temperature-dependent material properties of the models in a step-by-step procedure based on sub-sets of experimental data of isothermal experiments. The models and the material properties are validated based on the results of non-isothermal experiments. A good description of the time- and temperature-dependent cyclic ratchetting plasticity of IN100 is obtained for isothermal as well as non-isothermal loading with models including ratchetting terms in the kinematic hardening law and the material properties obtained with the proposed strategy.
Die vorliegende Arbeit beschäftigt sich mit dem Ermüdungs- und Schädigungsverhalten der in Verbrennungsmotoren eingesetzten Aluminiumgusslegierungen AlSi7Cu0,5Mg-T7 und AlSi12Cu3Ni2Mg-T7. Im Vergleich zur niederzyklischen sowie thermomechanischen Ermüdungsbeanspruchung führt die zusätzliche Überlagerung hochzyklischer Belastungen zu einer signifikanten Lebensdauerreduktion, die mit der Replika-Technik beobachteten Beschleunigung des Kurzrisswachstums erklärt werden kann. Frakto- und metallographische Untersuchungen zeigen, dass Rissinitiierung und Lebensdauerverhalten durch Gussdefekte sowie von belastungs- und temperaturabhängigen Schädigungsmechanismen bestimmt werden. Die Lebensdauern werden mit einem mechanismenbasierten Risswachstumsmodell vorhergesagt. Dazu wird der Schädigungsparameter DTMF,brittle entwickelt, der die charakteristischen Schädigungsmechanismen berücksichtigt. Die Legierung AlSi12Cu3Ni2Mg-T7 wird abschließend mit der Finite-Elemente-Methode und mikrostrukturbasierten Zellmodellen untersucht. Mit den Simulationsergebnissen können die experimentell beobachteten Schädigungsmechanismen fundiert gestützt werden.
A novelty solution for controls of assistive technology represent the usage of eye tracking devices such as for smart wheelchairs and robotic arms [10, 4]. In this context usage supporting methods like artificial feedback are not well explored. Vibrotactile feedback has shown to be helpful to decrease the cognitive load on the visual and auditive channels and can provide a perception of touch [17]. People with severe limitations of motor functions could benefit from eye tracking controls supported with vibrotactile feedback. In this study fundamental results will be presented in the design of an appropriate vibrotactile feedback system for eye tracking applications. We will show that a perceivable vibrotactile stimulus has no significant effect on the accuracy and precision of a head worn eye tracking device. It is anticipated that the results of this paper will lead to new insights in the design of vibrotactile feedback for eye tracking applications and eye tracking controls.
In diesem Artikel werden die neuesten Entwicklungen in der Forschungsgruppe um Herrn Prof. Dr. Wendt vorgestellt. Es wird der Einsatz des neuen 3-D-Druckers der Firma Neotech, sowie die neuesten Entwicklungen im Leuchtturmprojekt Flitzmo beschrieben. Zudem konnte dieses Jahr mit dem Projekt zum Einsatz von Robotik im Bereich Assisted Living begonnen werden.
When shopping online, it is usually not possible to view products in the same way as you are used to when shopping offline. With augmented reality (AR), it is not only possible to view the product in detail, but also to view it at home in the real environment. Such an AR application sets stimuli that can affect the users and their purchase decision and Word-of-mouth intention. In this work, we assume that when viewing a product in AR, not only affective internal states but also cognitive perception processes have an impact on purchase decision and Word-of-mouth intention. While positive affective reactions have already been studied in the context of AR, this paper will also describe inner cognitive perception processes, using the construct of AR authenticity. To test these assumptions, a study was conducted with 155 participants. The results show that both the purchase intention and the Word-of-mouth intention are influenced by the constructs of positive affective reactions and AR authenticity.
Im Rahmen eines GPS-Projektes ist an der Fachhochschule Offenburg ein Konzept für einen experimentellen Navigationsempfänger entstanden. Hierfür wurde der digitale Teil entwickelt und aufgebaut. Für die Realisierung der Schaltung sollten benutzerprogrammierbare Gate Arrays von Xilinx (LCAs) verwendet werden, die sich schon bei einer anderen Arbeit an der Fachhochschule bewährt hatten.
Nachfolgend möchte ich dem Leser einen Überblick über das GPS-System und die Entwicklung der LCAs geben.
An analytical and numerical study of the wobbling dynamics of friction disks is presented. Of particular interest is the excitation mechanism taking into account two contrarian effects both originating in dry friction: the circulatory terms describing the energy input due to the sliding contacts and the friction induced damping which stabilizes the system. Balance of these terms determines the instability domain in the parameter space. It is shown that there is a slip threshold so that, if the slip is under this limit, the system remains stable. If the slip is larger than this limit, then the criterion of stability is determined by the relation between the friction coefficient and the internal damping. The limit cycle appearing in the unstable domain is also investigated. It is shown that the limit cycle can be described as a kind of a regular reverse precession of the wobbling disc. Its amplitude is limited by the geometric nonlinearity and partial contact loss. Analytic results are compared with numeric simulations.
Das Wort Geothermie kommt aus dem Griechischen und setzt sich aus „Geo“ = Erde und „Thermie“ = Wärme zusammen. Bei der Geothermie wird die Wärme des warmen Untergrunds genutzt. Geothermie ist eine regenerative (CO2 freie), stetig verfügbar, von Witterungseinflüssen, Tages- und Jahreszeiten unabhängige Energiequelle, was sie von anderen regenerativ/erneuerbaren Energien wie z. B. Wind und Photovoltaik unterscheidet. Tiefengeothermische Kraftwerke sind grundlastfähig und können andere CO2 intensive Grundlastkraftwerke wie Steinkohlekraftwerke ersetzen. Es wird die oberflächennahe (0–400 m) und die tiefe Geothermie (> 400 m) unterschieden. Oberflächennahe Geothermie wird zur Wärmeversorgung von Gebäuden eingesetzt. Tiefe Geothermie kommt zur Strom- und Wärmeerzeugung zum Einsatz.
This paper analyzes the applicability of existing communication technology on the Smart Grid. In particular it evaluates how networks, e.g. Peer-to-Peer (P2P) and decentralized Virtual Private Network (VPN) can help set up an agent-based system. It is expected that applications on Smart Grid devices will become more powerful and be able to operate without a central control instance. We analyze which requirements agents and Smart Grid devices place on communication systems and validate promising approaches. The main focus is to create a logical overlay network that provides direct communication between network nodes. We provide a comparison of different approaches of P2P networks and mesh-VPNs. Finally the advantages of mesh-VPN for agent-based systems are worked out.
JARDIN GLOCAL
(2020)
ABSCHIED VOM AUSSEN
(2019)
Beuys-Gespräch
(2022)
Das im Rahmen psychosomatischer und neurologischer Grundlagenforschung an der Uniklinik Heidelberg entwickelte Experimentalsystem der „zweigriffigen Baumsäge“ kann als bio-kybernetisches Experimentalsystem erster Stunde bezeichnet werden. Der Psychosomatiker und Philosoph Martin Dornberg und der Medienkünstler Daniel Fetzner diskutieren in einem Gespräch Kontexte und Folgen der um den Heidelberger Psychosomatiker Victor v. Weizsäcker in den 1940/1950er Jahren durchgeführten medizinischen Experimente in den Bereichen von Medizin und Psychotherapie einerseits, aber auch in den Technik- und Medienwissenschaften, der Kybernetik und der Medienkunst. Herausgearbeitet werden Querbezüge zu den von den Autoren durchgeführten künstlerisch-philosophischen Forschungen in Form von Installationen, Performances und interaktiven Webdokumentationen.
DE\GLOBALIZE
(2020)
Die Allgegenwart der elektronischen Hypersphäre weicht das Körperempfinden zunehmend auf. Umhüllt vom Rauschen der Cloud verliert das postmediale Selbst an Kontur, die zeitlichen und räumlichen Topologien des Ich erfahren immer neue Faltungen und Teilungen. Dies ist der Untersuchungsgegenstand von »Inter- corporeal Splits« (2010–2013) eines Zyklus’ von drei Skype-Performances über die Medialität von Stimme, Haut und Rhythmus.
In the past decades, developments in the fields of medicine, new media, and biotechnologies challenged many representations and practices, questioning the understanding of our corporeal limits. Using concrete examples from literary fiction, media studies, philosophy, performance arts, and social sciences, this collection underlines how bodily models and transformations, thought until recently to be only fictional products, have become a part of our reality. The essays provide a spectrum of perspectives on how the body emerges as a transitional environment between fictional and factual elements, a process understood as faction.
Our media-artistic performances and installations, INTERCORPOREAL SPLITS (2010–2013), BUZZ (2014–2015), W ASTELAND (2015–2016), as well as our new collaboration with Bruno Latour , DE\GLOBALIZE (2018–2020), are not just about polyphony. Here, however, we rediscover them under this heading, thus giving them a new twist, while mapping out issues, mechanisms and functional modes of the polyphonic.
Partizipatives Parasitieren
(2016)
Die in diesem Aufsatz angesprochenen drei Skype-Performances, die wir im Zeitraum von 2010 bis 2013 durchgeführt haben, fokussieren nicht auf die trennenden Momente der handelnden Subjekte und ihrer Medien, sondern verfolgen eine radikal verkörperte, techno-ökologische Sichtweise. Im Kern untersuchen wir erweiterte Phänotypen , die durch das fortlaufende Parasitiert-Werden unserer Organismen durch die elektronischen Kanäle entstehen. So gesehen verbinden sich via Skype keine getrennten Personen und Orte, sie bilden vielmehr über die Präsenzerfahrung u.a. von Stimme, Haut und Rhythmus eine gemeinsame Umwelt und öffnen temporär einen ‚Dritten Raum‘ bzw. einen ‚Dritten Körper‘. Mensch, Maschine und Umwelt entwickeln durch die Medialisierung eine emergente Bezogenheit organischer und anorganischer Milieus, eine taktil/haptisch-mediale, verkörperte Ökologie. Das ist eine zentrale Annahme unserer Versuchsreihen.
JARDIN GLOCAL
(2021)
Das künstlerische Forschungsprojekt DE/GLOBALIZE ist eine medienökologische Suchbewegung nach dem Terrestrischen. Im abschließenden Kapitel JARDIN GLOCAL schwenkt der Fokus von den Matters of Fact in Indien, über Matters of Concern in Ägypten hin zu Matter of Care am Oberrhein. Von Matter, Materie, über Mater, die Mutter-Erde, hin zum Garten – als eine Welt innerhalb von Welten, die einem zu Füßen liegt. Wir verstehen JARDIN GLOCAL als ein Labor, in dem der Mensch mit sich in Beziehung tritt. Ein Ort, der sich zwischen Hu- manisierung und Ausbeutung bewegt; der oft überraschende Gewächse, Eingriffe und Prozesse hervorbringt. Vor allem aber als einen Topos, der besondere Beobachtungen in Gang setzt.
Critical theory and philosophy across many fields in the humanities has become awash with what has been characterised as ‘the material turn’. This material turn, which seems to involve varying combinations of what is known as Object Orientated Ontology (Harman), Actor-Network Theory (Latour), process philosophy (Whitehead), speculative realism (Bryant), or agential realism (Barad), emphasises some move toward a posthuman understanding of what the world is, and our relation to it.
DE\GLOBALIZE
(2022)
The artistic research cycle DE\GLOBALIZE is a media ecological search movement for the terrestrial. After examining matters of fact in India (2014-18), matters of concern in Egypt (2016-2019) and matters of care in the Upper Rhine (2018-22), the focus turns toward matters of violence in the Congo (2022). From matter to mater, mother-earth, the garden to exploitation. From science, water and climate to migration, oppression and extermination.
The long-term research is accessible through interactive web documentation. The platform serves as a continuous media-archaeological archive for a speculative ethnography. The relational structure of the videographic essay is enabling the forensic processing of single documents in the sense of the actor-network theory.
The subject of the presentation at IFM is a field trip to the Congo planned for March 2022, which will focus on the ambivalence of violence and care in collaboration with local artists. The field trip is based on the postcolonial reflection luderitzcargo by the author from 1996, in which a freight container was transformed into a translocal cinema in Namibia.
Through the journey to Congo, a group of media artists, a psychotherapist, a theater dramaturg, a filmmaker and a philosopher intend to explore the political, technological and psycho-geographic borders. By artistic interventions with locals, we want to interfere with relational string figures as part of the new Earth Politics. They are focusing on the displaced consumption of resources which are hard-fought and guarantee prosperity in the global north. The so-called ghost acreages are repressed and justified as part of a civilizational mission. With this trip, we want to confront our self-lies with the ones of our hosts. We want to confront ourselves with the foreign, the dark and the displaced ghosts within ourselves. In the presentation at the #IFM2022 Conference, the platform DE\GLOBALIZE will be problematized itself as an example of epistemic violence for the ethnographic memory of (Western) knowledge.
We are not the missionaries but the perplexed travellers. In our search movement, we are dealing with psychoanalysis, video, performance and trance. As disoriented white men we try the reversal of Black Skin and White Mask by Franz Fanon without blackfacing. We will not only care about the sensitivity of our skin but that of our g/hosts and the one of mother earth.
Inner Congo
(2023)
This research-creation project, part of the DE\GLOBALIZE artistic research cycle presented at the #IFM2022 Conference, investigates the complexities of Congo violence, care, and colonialism. Drawing on Michel Serres' metaphor of the great estuaries, the study explores the topology of interactive documentaries, blending theory, emotion, and personal experiences. Accessible through the interactive web documentation at http://deglobalize.com, the platform offers a media-archaeological archive for speculative ethnography, enabling the forensic processing of single documents in line with actor-network theory.
Seismic data processing relies on multiples attenuation to improve inversion and interpretation. Radon-based algorithms are often used for multiples and primaries discrimination. Deep learning, based on convolutional neural networks (CNNs), has shown encouraging applications for demultiple that could mitigate Radon-based challenges. In this work, we investigate new strategies to train a CNN for multiples removal based on different loss functions. We propose combined primaries and multiples labels in the loss for training a CNN to predict primaries, multiples, or both simultaneously. Moreover, we investigate two distinctive training methods for all the strategies: UNet based on minimum absolute error (L1) training, and adversarial training (GAN-UNet). We test the trained models with the different strategies and methods on 400 synthetic data. We found that training to predict multiples, including the primaries …
An important step in seismic data processing to improve inversion and interpretation is multiples attenuation. Radon-based algorithms are often used for discriminating primaries and multiples. Recently, deep learning (DL), based on convolutional neural networks (CNNs) has shown promising results in demultiple that could mitigate the challenges of Radon-based methods. In this work, we investigate new different strategies to train a CNN for multiples removal based on different loss functions. We propose combined primaries and multiples labels in the loss for training a CNN to predict primaries, multiples, or both simultaneously. We evaluate the performance of the CNNs trained with the different strategies on 400 clean and noisy synthetic data, considering 3 metrics. We found that training a CNN to predict the multiples and then subtracting them from the input image is the most effective strategy for demultiple. Furthermore, including the primaries labels as a constraint during the training of multiples prediction improves the results. Finally, we test the strategies on a field dataset. The CNNs trained with different strategies report competitive results on real data compared with Radon demultiple. As a result, effectively trained CNN models can potentially replace Radon-based demultiple in existing workflows.
Seismic data has often missing traces due to technical acquisition or economical constraints. A compete dataset is crucial in several processing and inversion techniques. Deep learning algorithms, based on convolutional neural networks (CNNs), have shown alternative solutions that overcome limitation of traditional interpolation methods e.g. data regularity, linearity assumption, etc. There are two different paradigms of CNN methods for seismic interpolation. The first one, so-called deep prior interpolation (DPI), trains a CNN to map random noise to a complete seismic image using only the decimated image itself. The second one, referred as standard deep learning method, trains a CNN to map a decimated seismic image into a complete one using a dataset of complete and artificially decimated images. Within this research, we systematically compare the performance of both methods for different quantities of regular and irregular missing traces using 4 datasets. We evaluate the results of both methods using 5 well-known metrics. We found that DPI method performs better than the standard method if the percentage of missing traces is low (10%) and otherwise if the level of decimation is high (50%).
In this work, we explore three deep learning algorithms apply to seismic interpolation: deep prior image (DPI), standard, and generative adversarial networks (GAN). The standard and GAN approaches rely on a dataset of complete and decimated seismic images for the training process, while the DPI method learns from a decimated image itself, without training images. We carry out two main experiments, considering 10%, 30%, and 50% of regular and irregular decimation. The first tests the optimal situation for the GAN and the standard approaches, where training and testing images are from the same dataset. The second tests the ability of GAN and standard methods to learn simultaneously from three datasets, and generalize to a fourth dataset not used during training. The standard method provides the best results in the first experiment, when the training distribution is similar to the testing one. In this situation, the DPI approach reports the second best results. In the second experiment, the standard method shows the ability to learn simultaneously and effectively three data distributions for the regular case. In the irregular case, the DPI approach is more effective. The GAN approach is the less effective of the three deep learning methods in both experiments.
Electrode modelling and simulation of diagnostic and pulmonary vein isolation in atrial fibrillation
(2022)
Rectifiersare vital electronic circuits for signal and power conversion in various smart sensor applications. The ability to process low input voltage levels, for example, from vibrational energy harvesters is a major challenge with existing passive rectifiers in printed electronics, stemming mainly from the built-in potential of the diode's p-njunction. To address this problem, in this work, we design, fabricate, and characterize an inkjet-printed full-wave rectifier using diode-connected electrolyte-gated thin-film transistors (EGTs). Using both experimental and simulation approaches, we investigate how the rectifier can benefit from the near-zero threshold voltage of transistors, which can be enabled by proper channel geometry setting in EGT technology. The presented circuit can be operated at 1-V input voltage, featuring a remarkably small voltage loss of 140 mV and a cutoff frequency of ~300 Hz. Below the cutoff frequency, more than 2.6-μW dc power is obtained over the load resistances ranging from 5 to 20 kQ. Furthermore, experiments show that the circuit can work with an input amplitude down to 500 mV. This feature makes the presented design highly suitable for a variety of energy-harvesting applications.
Electrolyte-gated, printed field-effect transistors exhibit high charge carrier densities in the channel and thus high on-currents at low operating voltages, allowing for the low-power operation of such devices. This behavior is due to the high area-specific capacitance of the device, in which the electrolyte takes the role of the dielectric layer of classical architectures. In this paper, we investigate intrinsic double-layer capacitances of ink-jet printed electrolyte-gated inorganic field-effect transistors in both in-plane and top-gate architectures by means of voltage-dependent impedance spectroscopy. By comparison with deembedding structures, we separate the intrinsic properties of the double-layer capacitance at the transistor channel from parasitic effects and deduce accurate estimates for the double-layer capacitance based on an equivalent circuit fitting. Based on these results, we have performed simulations of the electrolyte cutoff frequency as a function of electrolyte and gate resistances, showing that the top-gate architecture has the potential to reach the kilohertz regime with proper optimization of materials and printing process. Our findings additionally enable accurate modeling of the frequency-dependent capacitance of electrolyte/ion gel-gated devices as required in the small-signal analysis in the circuit simulation.
Printed electronics can benefit from the deployment of electrolytesas gate insulators,which enables a high gate capacitance per unit area (1–10 μFcm−2) due to the formation of electrical double layers (EDLs). Consequently, electrolyte-gated field-effect transistors (EGFETs) attain high-charge carrier densities already in the subvoltage regime, allowing for low-voltage operation of circuits and systems. This article presents a systematic study of lumped terminal capacitances of printed electrolyte-gated transistors under various dc bias conditions. We perform voltage-dependent impedancemeasurements and separate extrinsic components from the lumped terminal capacitance.
The proposed Meyer-like capacitance model, which also accounts for the nonquasi-static (NQS) effect, agrees well with experimental data. Finally, to verify the model, we implement it in Verilog-A and simulate the transient response of an inverter and a ring oscillator circuit. Simulation results are in good agreement with the measurement data of fabricated devices.
The manufacturing of conventional electronics has become a highly complicated process, which requires intensive investment. In this context, printed electronics keeps attracting attention from both academia and industry. The primary reason is the simplification of the manufacturing process via additive printing technology such as ink-jet printing. Consequently, advantages are realized such as on-demand fabrication, minimal material waste and versatile choice of substrate materials. Central to the development of printed electronic circuits are printed transistors. Recently, metal oxide semiconductors such as indium oxide have become promising materials for the fabrication of printed transistors due to their high charge mobility. Furthermore, electrolyte-gating also provides benefits such as the low-voltage operation in sub-1 V regime due to the large gate capacitance provided by electrical double layers. This opens new possibilities to fabricate printed devices and circuits for niche applications.
To facilitate the design and fabrication of printed circuits, the development of compact models is necessary. However, most of the current works have focused on the study of the static behavior of transistors, while the in-depth understanding of other characteristics such as the dynamic or noise behavior is missing. To this end, the purpose of this work is the comprehensive study on capacitance and noise properties of inkjet-printed electrolyte-gated thin-film transistors (EGT) based on indium oxide semiconductors. Proper modeling approaches are also proposed to capture accurately the electrical behaviour, which can be further utilized to enable advanced analysis of digital, analog and mixed-signal circuits.
In this work, the capacitance of EGTs is characterized using voltage-dependent impedance spectroscopy. Intrinsic and extrinsic effects are carefully separated by using de-embedding test structures. Also, a dedicated equivalent circuit model is established to offer accurate simulations of the measured frequency response of the gate impedance. Based on that, it is revealed that top-gated EGTs have the potential to reach operation frequency in the kHz regime with proper optimizations of materials and printing process. Furthermore, a Meyer-like model is proposed to accurately capture the capacitance-voltage characteristics of the lumped terminal capacitance. Both parasitic and nonquasi-static effects are considered. This further enables the AC and transient analysis of complex circuits in circuit simulators.
Following, the study of noise properties in the field of printed electronics is conducted. Low-frequency noise of EGTs is characterized using a reliable experimental setup. By examining measured noise spectra of the drain current at various gate voltages, the number fluctuation with correlated mobility fluctuation has been determined as the primary noise mechanism. Based on that, normalized flat-band voltage noise can be determined as the key performance metrics, which is only 1.08 × 10−7 V^2 µm^2, significantly lower in comparison with other thin-film technologies, which are based on dielectric gating and semiconductors such as IZO and IGZO. A plausible reason could be the large gate capacitance offered by the electrical double layers. This renders EGT technology useful for low-noise and sensitive applications such as sensor periphery circuits.
Last but not least, various circuit designs based on EGT technology are proposed, including basic digital circuits such as inverters and ring oscillators. Their performance metrics such as the propagation delay and power consumption are extensively characterized. Also, the first design of a printed full-wave rectifier is presented by using diode-connected EGTs, which features near-zero threshold voltage. As a consequence, the presented rectifier can effectively process input voltage with a small amplitude of 100 mV and a cut-off frequency of 300 Hz, which is particularly attractive for the application domain of energy harvesting. Additionally, the previously established capacitance models are verified on those circuits, which provide a satisfactory agreement between the simulation and measurement data.
Cellular phone antennas are generally designed to have radiation patterns that are as omnidirectional as possible. Omnidirectional antennas allow a phone’s radio to work well for many orientations of the phone with respect to the cellular base station. Recent studies, however, are generating uncertainty about the health effects of prolonged exposure to electromagnetic (EM) radiation from cellular phones. In this paper, an antenna array is designed primarily to minimize users’ exposure to EM radiation. The antenna comprises a beamforming 4 by 3 array of microstrip patch antennas that is controlled by an accelerometer-only inertial navigation system. The proposed design reduces radiated power directed toward the user to below 10% of the total in the worst case.
Im Rahmen dieses Projekts wurde im Labor Telekommunikationstechnik der Hochschule Offenburg die Übertragungsqualität von Mehrantennensystemen durch theoretische Analysen und Simulationen analysiert. Dabei zeigt sich bereits in der ersten Projektphase bei einfachen Mehrantennenkonfigurationen mit einer Sendeantenne und mehreren Empfangsantennen wie aufgrund von Antennendiversität bei verschiedenen Kombinationsstrategien der Empfangssignale sich die Übertragungsqualität bei Rayleigh Fading deutlich verbessert.
Die mediale Unterhaltung der Passagiere in Flugzeugen während des Flugs mit In-flight Entertainment IFE-System wird für Fluggesellschaften immer wichtiger. Somit steigen auch die Anforderungen an ein IFE-System hinsichtlich Datenrate, Zuverlässigkeit und Flexibilität. Ziel des Projekts „Sprechende Sitzschiene“ ist es, Multi-Media-Daten innerhalb eines IFE-Systems berührungslos über die Sitzschiene eines Flugzeugs zu den Passagiersitzen zu übertragen. Ein erster einfacher Demonstrator wurde bereits 2009 einem internationalen Fachpublikum auf der Paris Air Show in Le Bourget präsentiert. Ein weiterentwickeltes System hat bereits auf der Aircraft Interiors Expo 2010 in Hamburg für Aufsehen in der Fachwelt gesorgt. Der neueste Demonstrator der 3. Generation, nutzt nun modernste Übertragungstechnologien auf der Basis der Mehrträgermodulation OFDM für eine zuverlässige Datenübertragung, wie sie z. B. auch beim Digitalen Fernsehen (DVB) oder bei Mobilfunktechnologien der 4. Generation (LTE) Anwendung finden und zeichnet sich darüber hinaus durch eine volle Ethernet-Kompatibilität aus. Dadurch lassen sich alle bekannten Multi-Media-Anwendungen einfach mit diesem System realisieren.
Im Rahmen dieses Projekts wurde im Labor Telekommunikationstechnik der Hochschule Offenburg ein flexibel konfigurierbares Funknetz nach dem ZigBee-Standard aufgebaut. Mit Hilfe diverser Messgeräte und Analyse-Tools wurden die wesentlichen Performance Parameter dieses Funknetzes unter realen Betriebsbedingungen evaluiert. So wurden z.B. Erkenntnisse über die Empfängerempfindlichkeit, die effektiv erreichbare Datenrate sowie das Interferenzpotential gewonnen, die Voraussetzungen für die optimale Nutzung dieser neuen Funktechnologie sind.
Mehrantennensysteme (MIMO: MultipleInputMultipleOutput) sind seit einigen Jahren ein zentrales Forschungsthema in der Funkkommunikation. Die Analyse der Kanalkapazität solcher MIMOSysteme in [1] hat gezeigt, welches enorme Potenzial in dieser Technologie steckt. Dieses Potenzial kann auf verschiedene Arten genutzt werden. MIMOVerfahren können grundsätzlich in zwei Klassen eingeteilt werden. Die erste Klasse besteht aus Verfahren, die die Zuverlässigkeit der Übertragung über FadingKanäle verbessert. Dies wird entweder durch Verbesserung des jeweils wirksamen mittleren SNR (engl. SignaltoNoise power ratio) z. B. durch Beamforming oder durch Verminderung der Fluktuationen des SNR durch Diversitätstechniken erreicht. Die zweite Klasse bilden Verfahren, bei denen mehrere unabhängige Datenströme parallel über die verschiedenen Antennen durch räumliches Multiplexen (engl. Spatial Multiplexing) übertragen und so die Datenrate vervielfacht wird. Während bei den Diversitätstechniken und den Verfahren des Spatial Multiplexing die Übertragungseigenschaften zwischen den verschiedenen Sende- und Empfangsantennen durch z. B. ausgeprägte Mehrwegeausbreitung möglichst unkorreliert sein sollen, ist dies bei den Beamforming-Verfahren aber gerade nicht dienlich. Im Rahmen dieses Projekts wurde die Übertragungsqualität von Funksystemen mit MIMOArchitektur analysiert, die spezielle blockbasierte Codierungsverfahren verwenden, die nicht nur die zeitliche, sondern auch die räumliche Dimension zu der Informationsübertragung nutzen (SpaceTimeBlockCoding, STBC) und damit auf einen Diversitätsgewinn abzielen.
Prädiktive Betriebsverfahren
(2010)
Durch die Nutzung von Wetterprognosen lässt sich der Betrieb moderner Bürogebäude hinsichtlich Energiebedarf und Komfort verbessern. Ziel dieses Vorhabens ist es, mathematische Optimierungsverfahren für die Nutzung in der Gebäudeautomation zu entwickeln. Die Entwicklung einer vom Internet unabhängigen Versorgung mit Wetterprognosen über einen Langwellensender ist ebenfalls Gegenstand des Forschungsprojekts.
An der Fachhochschule Offenburg wurde im Sept. 93 das Projekt eines implantierbaren 16 Bit Mikroprozessor-Kernels FHOP ins Leben gerufen. Ausgehend von dem in einem Testchip erfolgreich erprobten umstrukturierten Entwurf wurde durch gezielten Einsatz von strukturiertem Routen unter Nutzung der Fähigkeiten zum hierarchischen Arbeiten in der MENTOR-IC-Station eine erheblich verkleinerte und flächenmäßig optimierte Struktur abgeleitet, die sich mit 4 Quadratmilimetern Fläche durchaus mit kommerziellen Mikroprozessor-Kerneln vergleichen läßt.
The idea of this game is to use a flashcard system to create a short story in a foreign language. The story is developed by a group of people by exchanging sentences via a flashcard system. This way, people can learn from each other without fear of making mistakes because the group members are anonymous.
The iSign project started in 2000 as a web-based laboratory setting for students of electrical engineering. In the meantime it has broadened into a heterogeneous learning environment offering learning material, adaptive user settings and access to a simulation tool. All these offerings can be accessed via web and wireless by different clients, such as PCs, PDAs and mobile phones. User adaptive systems offer unique and personalised environment for every learner and therefore are a very important aspect of modern e-learning systems. The iSign project aims to personalise the content structure based on the learner's behaviour, content pattern, policies, and system environment. The second aspect of the recent research and development within this project is the generation of suitable content and presentation for different clients. This generation is based additionally on the user preferences in order to obtain the desirable presentation for a given device. New, valuable features are added to the mobile application, empowering the user not only to control the simulation process with his mobile device but also to input data, view the simulation's output and evaluate the results. Experiences with students have helped to improve functionality and look-and-feel whilst using the iSign system. Our goal is to provide unconstrained, continuous and personalised access to the laboratory settings and learning material everywhere and at anytime with different devices.
In 2000 the iSign project started as a virtual web-based laboratory for students of study program electrical engineering. Continuous development in the last years led to a heterogeneous learning environment offering learning material, adaptive user settings and access to a simulation tool. Access is available via web and wireless devices such as PCs, Laptops, PDAs, smartphones and mobile phones. Our attempt to adapt the content to the user's needs and the currently used device led us to a XML based data structure. This report shows our research results about content adaptation based on XML data. The two main aspects for that process are: the device capabilities and the adaptation methods using XML data.
This paper shows the results of the evaluation of two sets of mobile web design guidelines concerning mobile learning. The first set of guidelines is concerned with the usage of text on mobile device screens. The second set is concerned with the usage of images on mobile devices. The evaluation is performed by eye tracking (objective) as well as questionnaires and interviews (subjective) respectively.
Nowadays the processing power of mobile phones, smartphones and PDAs is increasing as well as the transmission bandwidth. Nevertheless there is still the need to reduce the content and the need of processing the data. We discuss the proposals and solutions for dynamic reduction of the transmitted content. For that, device specific properties are taken into account, as much as for the aim to reduce the need of processing power at the client side to be able to display the 3D (virtual reality) data. Therefore, well known technologies, e.g. data compression are combined with new developed ideas to reach the goal of adaptive content transmission. To achieve a device dependant reduction of processing power the data have to be preprocessed at the server side or the server even has to take over functionality of weak mobile devices.
Virtual-Reality-Darstellung elektromagnetischer Felder in dreidimensionalen Mikrowellenstrukturen
(2000)
Untersuchungen haben gezeigt, daß der Mensch ein Vielfaches an Informationen in Form von visuellen Eindrücken, im Gegensatz zur textuellen Darstellung, verarbeiten kann. Mit Hilfe des numerischen Feld-Simulationsprogramms F3D können Mikrowellenstrukturen auf die Wechselwirkung mit elektromagnetischen Feldern untersucht werden. Das Programm F3D2VRML stellt die Ergebnisse in einer dreidimensionalen Virtual-Reality-Darstellung (VR) dar.
Damit ist es dem Betrachter möglich, mehr Informationen aufzunehmen, da die Informationen mit Formen und Farben im dreidimensionalen Raum visualisiert werden.
Nowadays the processing power of mobile phones, Smart phones and PDA is increasing, as well as the transmission bandwidth. Nevertheless there is still the need to reduce the content and the need of processing the data. Proposals and solutions for dynamic reduction of the transmitted content will be discussed. For that, device specific properties will be taken into account, aiming at reducing the need of processing power at the client side to display the 3D Virtual Reality data. Therefore, well known technologies like data compression are combined with new approaches to achieve the goal of adaptive content transmission. For device dependant reduction of processing power the data has to be pre-processed at the server side or the server itself has to take over functionality of weak mobile devices.