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AMiCUS - Bewegungssensor-basiertes Human-Robot Interface zur intuitiven Echtzeit-Steuerung eines Roboterarmes mit Kopfbewegungen
Get PDFWithin the work presented here, the demonstrator AMiCUS (Adaptive Head Motion Control for User-friendly Support) has been developed. AMiCUS senses the head motions of a tetraplegic user and uses these to control a robot arm in real-time. At first, a MEMS-based Attitude Heading Reference System (AHRS) suitable for head control has been chosen. Next, a solution has been proposed how to attach the AHRS to the head of a potential user to measure his head motion. A control structure has been developed that enables intuitive real-time control of a robot arm in Cartesian space using the 3 input signals provided by head motion. It has been taken into account that the Range of Motion (ROM) of a potential user can be restricted. Therefore, the control paradigm can be adapted to the individual user, using his full available ROM. Moreover, possibilities to generate control commands which can be integrated consistently into the existing control paradigm have been investigated in order to be able to turn the system on and off, and to perform switching operations using solely head motion. On this basis, the first version of the demonstrator, AMiCUS alpha v.1, has been realized. To allow safe and efficient operation, AMiCUS alpha v.1 provides acoustic and visual feedback to the user. Besides that, special attention has been paid to keeping the complexity of the implemented algorithms low to save resources, such as computing and battery power. The strengths and weaknesses of the system have been assessed during a user study with 25 subjects without motion limitations and 6 tetraplegics with severe motion limitations of the head. Both subjective and objective target quantities have been used. It could be shown that AMiCUS alpha v.1 enables smooth, precise and efficient control of a robot arm to perform simple manipulation tasks. AMiCUS could reliably distinguish between direct control signals and switching commands. Furthermore, no situation has been observed which has put the operational safety to a risk. Overall, user satisfaction was high. However, there were also points of criticism. These have been taken into account during the development of the follow-up version of the demonstrator, AMiCUS alpha v2.0. A tetraplegic exemplarily evaluated AMiCUS alpha v2.0 and compared it to its previous version, AMiCUS alpha v1.0. The direct comparison showed that AMiCUS alpha v2.0 was a subjective improvement compared to AMiCUS alpha v1.0. Most remaining problems, such as difficulties during the imagination of gripper rotations, are likely to be solved by means of learning effects. In a semi-realistic scenario the tetraplegic had the final task to pour water from a bottle into a glass. Like the other tasks, she could also solve this task independently. Overall, the results which could be obtained using the demonstrator AMiCUS are promising. Further development into a stand-alone assistive system or into a complement of a semi-autonomous system is conceivable
Referring Expression Generation in Situated Interaction
Get PDFWhile most current frameworks for reference handling are based on binary truth-theoretic knowledge representation, in this thesis I argue for a perspective on reference which emphasises the collaborative nature of reference. I present the Probabilistic Reference And GRounding mechanism (PRAGR) which uses flexible concept assignment based on vague property models and situational context in order to maximise the chance of communicative success. I demonstrate that PRAGR is capable of dealing with several property domains with different internal structures, such as graded adjectives, colour, shape, projective terms, and projective regions. Further, I show that PRAGR is fit to handle in an integrated fashion the most relevant challenges of Referring Expression Generation, in particular graded properties, spatial relations, and salience effects. In three empirical evaluation studies, I demonstrate the usefulness of PRAGR for situated referential communication
Senior innenbildung - Biographiearbeit mit Gastarbeiter innen der ersten Generation
No full textDie Arbeit setzt sich mit der Frage der Senior innenbildung unter aktuellen gesellschaftlichen Bedingungen und Entwicklungen auseinander. Im Zentrum der Auseinandersetzungen stehen explizit die Bildungsbenachteiligungen ehemaliger Gastarbeiter innen. Um diese zu minimieren, wird ein methodischer Vorschlag der Biographiearbeit, als möglicher Zugang zu Bildung in der nachberuflichen Lebensphase für ehemalige Gastarbeiter innen erarbeitet
Range expansion mechanisms of the invasive kelp Undaria pinnatifida
Get PDFSpecies invasions in marine habitats have dramatically increased in the last decades. This thesis revealed characteristics of the invasive kelp Undaria pinnatifida that support its invasive potential along various phases of the invasion process. Experiments, including morphological, physiological and biochemical analyses, explored traits of different life history stages. The kelp displayed broad physiological tolerance to the tested abiotic factors (desiccation, temperature, salinity). Based on its capability to survive extended periods of air exposure, overland transport is proposed as an invasion vector for U. pinnatifida. With regard to elevated temperatures the invader outperformed native kelps, indicating a competitive advantage in a warming ocean. Observations of simultaneously developing gametophytes revealed the occurrence of inter-specific interactions at microscopic stages. Interactions of U. pinnatifida and Macrocystis pyrifera resulted in an enhancement of the invader's performance
Distribution and Activity of Anammox and Sulfide-Oxidizing Nitrate-Reducing Bacteria in Oxygen Minimum Zones
No full textHighly productive marine upwelling regions that are located along continental boundaries play a critical role in the global ocean nitrogen budget. The high organic matter input in combination with the poor regional ventilation result in extremely low water column oxygen concentrations, or so-called oxygen minimum zones (OMZs). OMZs harbor a diverse community of anaerobic microorganisms including an enhanced nitrogen cycle. For instance, the microbial processes anammox and denitrification thrive in these waters, catalyzing the reduction of fixed nitrogen species (NO3-, NO2- and NH4 ) to the more inert form, N2 gas, thereby contributing to the loss of fixed nitrogen. Together the five major OMZs (which represent a small 1% of the global ocean volume) contribute to 30-50% of oceanic nitrogen loss. However, the biological and physical forces that regulate anammox and denitrification activity in OMZs remain poorly constrained. This thesis work aims to elucidate the dynamics that govern the activity and distribution of anammox and denitrifying (e.g. SUP05 and Arcobacter) bacteria in OMZs. In this work we employed a comprehensive range of techniques including cultivation, metagenomics, 15N-labeled stable isotope incubation experiments, and single-cell techniques in combination with oceanographic tools
8. Kolloquium Mikroproduktion: Fachbeiträge
No full textUm die speziellen Anforderungen der Mikrotechnik auf eine systematische Grundlage zu stellen und so eine beherrschte, auf den Mikrobereich zugeschnittene Produktion zu ermöglichen, wurden bzw. werden von der Deutschen Forschungsgemeinschaft (DFG) mehrere koordinierte Forschungsvorhaben gefördert. Das Kolloquium Mikroproduktion findet seit 2003 im Zweijahresrhythmus statt und dient der Vernetzung der Standorte. Zielgruppe sind Forscher und industrielle Anwender der Mikrotechnik. Im Rahmen des 8. Kolloquiums wurden Inhalte einer Vielzahl von aktuellen Folgeprojekten bereits abgeschlossener koordinierter Forschungsvorhaben sowie dem gastgebenden Sonderforschungsbereich 747 Mikrokaltumformen - Prozesse, Charakterisierung, Optimierung in Bremen thematisiert. In diesem Tagungsband sind wesentliche aktuelle wissenschaftliche Ergebnisse in peer-reviewten Beiträgen dokumentiert, die im Rahmen des gemeinsamen Kolloquiums am 27. und 28. November 2017 in Bremen vorgestellt wurden
Southern Patagonian climate the last 51,000 years : Insights from lipid biomarkers and their isotopes
No full textLaguna Potrok Aike (LPA) is situated in the core region of the Southern Hemispheric Westerlies (SHW) and provides an exceptional sedimentary archive to investigate the southern Hemisphere mid-latitude climate change over the last 51,000 years. This study gives the opportunity to reconstruct climatic and environmental conditions in an area sensitive to changes in polar and mid-latitude wind fields and hydrological regimes, and it provides insights into the complex interaction of terrestrial, marine and glacial environmental changes on glacial-interglacial timescales. Within the framework of this thesis the temperature and hydrological fluctuations of the maar lake were investigated using organic-geochemical proxies based on microbial membrane lipids (so called GDGTs) and compound-specific isotope analysis (d13C and dD) of plant-wax derived n-alkanes of different origins, respectively
Ocean impact on the 79 North Glacier, Northeast Greenland
Get PDFThe retreat and acceleration of marine-terminating glaciers around the coast of Greenland observed over the last two decades have partly been attributed to a warming of Atlantic Water (AW) circulating around the subpolar North Atlantic. This thesis investigates the impact of the ocean circulation on the 79 North Glacier (79NG), which has Greenland's largest floating ice tongue. One overall hypothesis tested in this thesis is whether a long-term warming of AW in Fram Strait has spread across the continental shelf off Northeast Greenland (NEG) toward the 79NG, which may explain the recent thinning observed at the floating ice tongue. A detailed bathymetry is crucial for studying pathways of AW across the NEG continental shelf. Thus, the first part of this thesis is devoted to an accurate representation of the continental shelf bathymetry and 79NG cavity geometry. Based on a collection of hydrographic data obtained between 1979 and 2016 it is shown that the Norske Trough, the southern branch of the characteristic C-shaped trough system on the continental shelf, is filled up by warm Atlantic Intermediate Water (AIW) exceeding 1 degree Celsius at depths below 200-250 m. Current velocities from moored and lowered ADCPs inside Norske Trough indicate that a boundary current transports warm AIW toward the 79NG. The results show that Norske Trough provides the main pathway for warm AIW from the continental shelf break toward the 79NG. Anomalies in AW temperatures in Fram Strait could reach the 79NG within 1.5 years. A unique data set comprising bathymetric, hydrographic, and current velocity observations obtained during the R/V Polarstern cruise PS100 in front of the 79NG calving front emphasizes the importance of the complex bathymetry for the heat transport into the cavity below the floating ice tongue. A density-driven gravity plume, steered by the bathymetry outside the cavity, transports warm AIW into the subglacial cavity. These findings imply that the AIW layer thickness on the continental shelf plays an important role in determining the strength of the overturning in the cavity and thereby melting at the base of the floating ice tongue. For the first time, the major exchange flow across the 79NG calving front (i.e., between the continental shelf and the 79NG cavity) was captured by synoptic hydrographic and velocity observations. A bottom-intensified flow transports 140 plus/minus 20 GW of heat into the cavity via a 500 m deep and 2 km wide depression. A heat supply of this magnitude causes an average melt rate of 8.3 plus/minus 2.1 m/yr at the ice base of the 79NG. By mixing of AIW and glacial meltwater (i.e., both basal meltwater and subglacial runoff), a shallow outflow of glacially modified AIW is generated. The observed ocean exchange flow across the 79NG calving front suggests that the overturning in the cavity has a strength of 36 plus/minus 17 mSv. Combining historic and recent hydrographic data from the 79NG cavity and the NEG continental shelf reveals a warming of AIW by 0.4 plus/minus 0.1 degree Celsius between the late 1990s and recent years. Numerical experiments performed with a one-dimensional ice-shelf plume model suggest that the observed changes go along with a 44 plus/minus 13% increase in average basal melt rates. The results verify the hypothesis that a long-term warming of AW in Fram Strait has spread across the continental shelf into the 79NG cavity and emphasize that the ocean is the main driver of the ice thickness loss at the 79NG. Warm AIW is also present at the Zachariae Isstrom (ZI) located 50 km south of the 79NG, which was shown for the first time from temperature measurements. The warming in AIW presumably has driven the disintegration of the floating ice tongue of ZI in 2012/14. A further warming of waters below the 79NG may cause a similar rapid loss of the entire floating ice tongue as observed at ZI
Towards the Compatibility of Professional and Scientific Learning Outcomes: Insights and Options in the Context of Competence Orientation
Get PDFThe steady increase in science-related requirements in operational areas of skilled and managing workforce is influencing worldwide the discourse on shaping professionalization. This article focuses on the compatibility of professional and scientific competence-oriented learning outcomes of qualification programmes within and across the education and training sectors. It is assumed that there is not, per se, a conceptual dichotomy in designing education and training programmes and credentials in a competence-oriented manner to address complex professional and scientific requirements in education and training in a compatible way. The article tries to shift the discussion from a systemic and institutional focus to a conceptual- and requirement-oriented perspective on qualification design. Using Germany as an example, it discusses the conceptual intersections of Vocational Education and Training and academic Higher Education on competence, and comparatively analyzes competence-oriented instruments for the classification and the transparency of learning outcomes and their application in the education practice of dual study programmes with vocational reference qualifications. On this basis, the article elucidates identified characteristics of comprehensive professional-scientific competences and relevant requirement areas in education and training. In addition, further prerequisites for an integrated competence acquisition in education programmes are discussed as well. It is assumed that these characteristics can also be regarded as important prerequisites for the connectivity of qualifications and permeable pathways within and between education systems
Book Review: Vocational Education and Training in Times of Economic Crisis
Get PDFThe book was published in the series Technical and Vocational Education and Training: Issues, Concerns and Prospects . Series Editor-in-Chief is Rupert MacLean. Editor of the volume is Matthias Pilz, professor and holder of the chair of Economic and Business Education and director of the German Research Center for Comparative Vocational Education and Training (G.R.E.A.T) at the University of Cologne in Germany