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This paper deals with system level design considerations for mm-size implantable electronic devices with wireless connectivity. In particular, it focuses on neural sensors as one application requiring such miniature interfaces. Common to all these implants is the need for power supply and a wireless interface. Wireless power transfer via electromagnetic fields is identified as a promising option for...
An implanted fully-integrated 65nm CMOS 1.1mm × 1.1mm × 0.8mm remotely-powered wireless transponder for implantable neural sensors provides 5uW for sensor interfaces, while consuming 3uW and transmitting 2Mbps at 330fJ/b without violating exposure limitations. This is accomplished by combining a time-multiplexed power and data transmission scheme with a reflective impulse transmitter architecture.
In this work, we describe a set of integrated and ambient sensors, that can be used for the identification and evaluation of suitable sensors for the assessment of psychophysiologic driver state. Applications using this information cover a wide spectrum from driver vigilance monitoring to in-car health management. However, application specific, unobtrusive integration of sensors is necessary to keep...
We investigate nonlinear optics related to the intra-excitonic 1s-2p heavy-hole transition in GaAs/AlGaAs quantum wells. Tuning intense terahertz (THz) light around this resonance we report (i) efficient second order sideband generation and (ii) first clear evidence of the Autler-Townes effect.
Solar cells made of upgraded metallurgical grade (UMG) silicon in general suffer from increased reverse currents at relatively low reverse bias easily attainable in standard solar cell modules. We show that the high net doping concentration, often inherent to UMG-Si feedstock, causes the reduction of the diode breakdown voltage of the soft breakdown. This type of breakdown occurs at recombination...
We report the investigation of two nonlinear optical phenomena which are related to intra-excitonic transitions in semiconductor quantum wells and thus occur in the THz range. This is, on one hand, the generation of THz sidebands of near-band gap radiation, a perturbative process, and on the other hand, the AC Stark effect manifested by the Autler-Townes splitting as a non-perturbative effect. Both...
This paper describes a system that deploys acoustic and linguistic information from speech in order to decide whether the utterance contains negative or non-negative meaning. An earlier version of this system was submitted to the Interspeech-2009 Emotion Challenge evaluation. The speech data consist of short utterances of the children's speech, and the proposed system is designed to detect anger in...
The human face is a rich source of information for the viewer and facial expressions are a major component in judging a person's affective state, intention and personality. Facial expressions are an important part of human-human interaction and have the potential to play an equally important part in human-computer interaction. This paper evaluates various active appearance model (AAM) fitting methods,...
In this paper we present a system for the interactive exploration of large-scale spatiotemporal city models. Our system focuses on interactive techniques that allow the user to navigate freely in space and time, and which can also be used to query particular features of the model. For that purpose we introduce a novel data structure based on a binary space partitioning tree. A four dimensional kD-tree...
Ubiquitous computing environments may offer dynamically discoverable services that can be utilized by adaptive applications to improve their functionality and quality of service. We have developed a general software development framework for context-aware adaptive applications. In this paper we present our novel modeling concepts that extend an existing component-based modeling approach by service-oriented...
Automated composition of services is a key functionality for the adoption of the service-oriented development paradigm. Solving this problem in practice requires the ability to consider asynchronous stateful services and to express complex composition requirements which may span different phases of the life-cycle of component services. In this paper we present a novel automated service composition...
The source of the fission neutron beam at the research reactor FRM II is a thermal-to-fast neutron converter. It consists of a pair of movable uranium plates which can be positioned in closest touch to beam tube SR10. The energy spectrum of the neutrons is essentially a Watt spectrum with a mean energy of 1.9 MeV. The beam is used for a great variety of applications, e.g., the structure of large samples...
We have identified at least five different local breakdown mechanisms according to the temperature coefficient (TC) and slope of their characteristics and electroluminescence (EL) under reverse bias. These are (1) early pre-breakdown (strongly negative TC, low slope), (2) edge breakdown (positive TC, low slope, no EL), (3) weak defect-induced breakdown (zero or weakly negative TC, moderate slope,...
The presented joint project is directed towards the development and verification of a flexible, lightweight and highly efficient Cu(In,Ga)Se2 (CIGSe) thin film solar cell technology on a polyimide foil substrate for space applications. The German activities to harmonize the present resources are a unique approach in the field of chalcopyrite based thin film solar cells in order to enable a beneficial...
The transition from analogue to digital television provided many benefits such as better picture quality and/or more channels. However, there are disadvantages in the digital world as well; most prominently the channel change takes longer than the user was accustomed to in the former analogue world. Therefore various solutions have been developed to speed up the channel change in digital video broadcast...
We examine the problem of partitioning a square into convex polygons which are as circular as possible. Circular means that the polygon's aspect ratio is supposed to be near 1. The aspect ration of a convex polygon denotes the ratio of the diameters of the smallest circumscribing circle to the largest inscribed disk. This problem has been solved for the equilateral triangle as well as for regular...
Inference of high-level context is becoming crucial in development of context-aware applications. An example is social context inference - i.e., deriving social relations based upon the user's daily communication with other people. The efficiency of this mechanism mainly depends on the method(s) used to draw inferences based on existing evidence and sample information, such as a training data. Our...
Inherent obstacles in current mobile applications are the limited input and output capabilities of mobile phones. In many ways, e.g. in terms of display capabilities and processing power, todaypsilas mobile phones are quite versatile and provide opportunity for a multitude of new applications. Conversely, mobile phones will always be somewhat limited by certain form factors that are intrinsic to their...
The present paper describes the development of an embedded data logging platform for research in diving physiology. It records oxygen saturation and other physiological parameters like heart rate and electrocardiography, plus physical parameters like water temperature and water pressure in real-time. All measured data is stored on SD-card in text files. Thus easy processing with standard programs...
It is a challenge for mobile robots to climb a vertical wall primarily due to requirements for reliable locomotion, high manoeuvrability, and robust and efficient attachment and detachment. Such robots have immense potential to automate tasks which are currently accomplished manually, offering an extra degree of human safety in a cost effective manner. In contrast to vacuum suction, magnetic adhesion,...
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