Nachgiebiger Elektrodenträger für Cochlea-Implantate mit fluidischer Aktuierung

The cochlear implant, consisting of a compliant electrode carrier (ET) and embedded electrodes with contact wires, is an auditory neuroprosthesis, which is surgically inserted into the inner ear (cochlea) in order to create an auditory impression in the hearing-impaired patients. For simplification of the insertion, a fluidically actuated electrode carrier with a changeable curvature is presented. The deformation of the ET is specifically manipulated by applying pressure to its interior and also by a non-stretchable thin fibre or stripe embedded in its wall. An analytical examination of scaling properties allows to use scaled structures for models and measurements. In order to determine the geometry of the ET, a model-based synthesis – FE method combined with analytical modelling – is carried out. The synthesis resulted in a conical shape of the ET with a cylindrical cavity closed at one end and a fiber running parallel to the cavity. Experimental studies on a measuring geometry show a maximum deviation of 0,6 bar at a maximum internal pressure of 6 bar. The investigations show that the proposed synthesis method is suitable for the development of surgical instruments with adjustable curvature.     

Locales: A Module System for Mathematical Theories

Locales are a module system for managing theory hierarchies in a theorem prover through theory interpretation. They are available for the theorem prover Isabelle. In this paper, their semantics is defined in terms of local theories and morphisms. Locales aim at providing flexible means of extension and reuse. Theory modules (which are called locales) may be extended by definitions and theorems. Interpretation to Isabelle’s global theories and proof contexts is possible via morphisms. Even the locale hierarchy may be changed if declared relations between locales do not adequately reflect logical relations, which are implied by the locales’ specifications. By discussing their design and relating it to more commonly known structuring mechanisms of programming languages and provers, locales are made accessible to a wider audience beyond the users of Isabelle. The discussed mechanisms include ML-style functors, type classes and mixins (the latter are found in modern object-oriented languages).     

Adaptive Resource Management Platform for Reconfigurable Networks

Users’ expectations towards technology, in terms of quality, service availability and accessibility are ever increasing. Aligned with this, the wireless world is rapidly moving towards the next generation of systems, featuring cooperating and reconfiguring capabilities for coexisting (and upcoming) Radio Access Technologies (RATs), so that to improve connectivity and reduce costs. In this respect, conventional planning and management techniques ought to be replaced by advanced schemes that consider multidimensional characteristics, increased complexity and high speeds. To this effect, means are needed capable to support scalability and to cater for advanced service features, provided to users at high rates and cost-effectively. This article provides a scheme to optimize resource management in future systems, by describing a platform that accommodates engineering mechanisms that deal with dynamic, demand driven planning and managing of spectrum and radio resources in reconfigurable networks. To do so, it first discusses the fundamentals and the approach followed in the proposed architecture and then investigates the basic functional modules. The architecture is validated through a set of use-cases that exemplify the operational applicability and efficiency in a wide range of communication scenarios.

Multi-Agent Radio Resource Allocation

This paper presents a spatially distributed and dynamic billing, pricing and allocation mechanism for which a user terminal requires Cognitive Radio abilities. That is, the Cognitive Radio abilities will be applied to the economical environment. The radio resource goods are allocated to the users by a multi-unit sealed-bid auction. Intelligent entities like the bidding strategy have to represent operator’s and users’ behavior and to make decisions for them in order to fulfill the preferences and QoS. The main functionalities, used to execute the dynamic auction sequence and located in the MAC are described, assuming the entities possess Cognitive Radio abilities.

Application of generalized dynamic neural networks to biomedical data

This paper reviews the application of continuous recurrent neural networks with time-varying weights to pattern recognition tasks in medicine. A general learning algorithm based on Pontryagin's maximum principle is recapitulated, and possibilities of improving the generalization capabilities of these networks are given. The effectiveness of the methods is demonstrated by three different real-world examples taken from the fields of anesthesiology, orthopedics, and radiology.     

Tailoring (1)H Spin Dynamics in Small Molecules via Supercooled Water: A Promising Approach for Metabolite Identification and Validation

Metabolic mixtures are often analyzed via NMR spectroscopy as it provides a metabolic profile without sample alteration in a noninvasive manner. These mixtures however tend to be very complex and demonstrate considerable spectral overlap resulting in assignments that are sometimes ambiguous given the range of current NMR methods available. De novo molecular identification in these mixtures is generally accomplished using chemical shift information and J-coupling based experiments to determine spin connectivity information, but these techniques fall short when a molecule of interest contains nonrelaying centers. A method is presented here that enhances intramolecular spatial interactions via supercooled water and uses the resulting spatial correlations to edit mixtures. This is accomplished by utilizing nuclear Overhauser effect spectroscopy (NOESY) at subzero temperatures in capillaries to enhance NOE and provide more complete spin systems. This technique is applied to a standard mixture of three known molecules in D(2)O with overlapping resonances and is further demonstrated to assign molecules in a worm tissue extract. The current method proves to be a powerful complement to existing methods such as total correlation spectroscopy (TOCSY) to expand the range of molecules that can be assigned in situ without physical separation of mixtures.     

3D optical coherence tomography as new tool for microscopic investigations of nucleate boiling on heated surfaces

Boiling phenomena are an important aspect in security and efficiency for technical applications with high heat flux like nuclear reactors. This study presents optical coherence tomography (OCT) as a novel modality for three-dimensional and two-dimensional time resolved imaging of nucleate boiling on heated surfaces on a microscopic scale with high spatial (<10 μm) and temporal (>25 frames per second) resolution. Within this study, a borosilicate glass plate coated with an optically transparent and electrically conductive indium tin oxide (ITO) layer with a thickness of approximately 100 nm was used as heating surface. The combination of these two properties allows optical inspection of the nucleate boiling from the backside by OCT focused on the formation, growth and detachment of single bubbles. We demonstrated for the first time that OCT is an excellent tool to acquire two-dimensional and three-dimensional images of the base of vapor bubbles from the backside of the heated surface. The acquired images allow for instance the temporally resolved measurement of the bubble diameter, diameter of the bubble base and the contact angle. Exploiting the phase information of the acquired OCT signal stacks allows imaging the movement of the bubble surrounding fluid. We think that OCT will provide many new insights into the boiling phenomena at the bubble base. The recent enhancement of the acquisition rates of OCT systems will facilitate four-dimensional imaging of single bubble evaporation procedures in the nearer future.