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Brain-Computer Interfaces (BCIs) enable people to control appliances without involving the normal output pathways of peripheral nervesand muscles. A particularly promising type of BCI is based on the Steady-State Visual Evoked Potential (SSVEP). Users can selectcommands by focusing their attention on repetitive visual stimuli(RVSi) that change one of their properties (e.g. color or pattern) with a certain frequency. These properties as well as the devicethe RVSi are rendered on, can greatly affect the performance, applicability, comfort and safety of the BCI. Despite this fact, stimulation properties have received fairly little attention in the BCI literature to this date. Furthermore, a heavy emphasis is placedon BCI performance to the detriment of other important factors suchas comfort and safety. The research reported in this document aimsat studying the effects of stimulation properties on performance aswell as comfort of SSVEP-based BCIs. Research was performed in bothoffline and online settings, using a custom made high-performance BCI. Comfort was measured using a custom questionnaire. A largevariability across subjects was found, but the results confirm that stimulation properties have a considerable impact on performance and comfort of SSVEP based BCIs. In general, a large difference between stimulation states is beneficial for BCI performance, but detrimen-tal to user comfort. A couple of configurations were found that provide a good compromise between comfort and performance.

Many photovoltaic cells and OLEDs are covered by cover glass or foil to protect the device against oxygen and moisture. The cover glassor foil is semitransparent for infrared radiation and conducts the heat and blurs lock-in thermograms. In lock-in thermograms of OLEDs with cover glass short circuits raise typically 10 mK in temperature,where as literature and observations suggest that polymers decompose into gas at way higher temperature behind the glass. A good interpretation of lock-in thermograms may be done by the understanding of the heat conduction and radiation through cover glass. Modelling of heat conduction and radiation around a short circuit in cover glass will be presented as well as first validation experiments where a short circuit has been imitated by a laser.

A fully autonomous inductive boost converter for indoor photovoltaic harvesting with maximum power point tracking circuit is implemented in a commercial 0.25um CMOS process. The converter can handle input power from 5uW up to 10mW and charge a battery or a super-capacitor up to 5V. Its control circuit consumes between 0.8uA and 2.1uA depending on the input power level, resulting in a peak end-to-end efficiency of 70% when tracking a maximum input power of 17uW.

Brain-computer interfaces (BCI) based on Steady State Visual Evoked Potential (SSVEP) can provide higher information transfer rate and require shorter calibration than BCIs based on other modalities. For safety and comfort, the frequency of the repetitive visual stimuli seliciting the SSVEP should be higher than 30 Hz. However, in such frequency range, only a limited number of frequencies can elicit sufficiently strong SSVEPs for BCI purposes. Thus, the conventional approach, consisting in presenting various repetitive visual stimuli at different frequencies, is not feasible for high frequencies. Indeed this would bring low communication bitrates. To increase the number of possible repetitive visual stimuli, we consider modulating the phase of the stimulus instead of the frequency. In this paper, we present an approach to reliably detect the stimulus phase from the recorded SSVEP.

Ambient Assisted Living (AAL) systems and services aim to provide a solution for growing healthcare expenses and degradation of life quality of elderly using information and communication technology. Inparticular AAL solutions are being created that are heavily based on web services an sensor technologies. AAL solutions have to deal witha large amount of privacy sensitive information and consequently AAL systems must be designed with strong attention to security in order to properly manage user consent and protect the confidentiality, integrity and availability of its resources. Analysis shows thatexisting AAL frameworks have serious shortcomings with respect to the security controls they offer, typically basic authentication, encryp-tion and access control. An important challenge is to enable users tostay in control of their data in a setting where that data is exchanged between several different service providers and where users want to share data with their friends and relatives. This report presents a high level security architecture that describes a set of security controls that must be offered by AAL frameworks and proposes an ad-vanced authorization architecture for AAL. In particular it incorporates the eXtensible Access Control Language (XACM L) and a protocol for transferring policies in order to support end to end access and usage control in AAL systems.

User interfaces of mobile consumer devices are becoming increasingly complex. To address this complexity touch-screen interfaces are used. They allow flexible design of the user interfaces but lack the tactile feedback mechanical buttons provide, limiting ease of use. Dielectric Elastomer Actuator (DEA) promise to combine the flexibilityof a touch-screen with the intuitive use of classical buttons, but require high driving voltages. Providing the driving voltages in a mobile device, where size and energy are limited, is a main challenge. In this thesis, a working demonstrator of a mobile consumer device providing a vibrotactile feedback User Interface (UI) with DEAs is built. Based on a principle structure of a DEA driving electronics, devised by Haus [Hau10] an improved driving electronics is designed. The main aspects of improvement are over-all volume and energy efficiency of the circuits. Safety concerning the high voltage outputs in a mobile consumer device is addressed. The complete system consumes 0.52W input power and has a dimension of 110mm x 45mm x 20mm. The driving electronics generates eight high voltage signals with an amplitude of up to 1100V for driving the DEA, while being supplied by a voltage of 3.7V, provided by a Lithium-Ion (LiIo) battery. The control electronics sets the frequency and duty-cycle of the rectangular waveform of the tactile feedback signal. The frequency is freely programmable from DC up to 300 Hz, the dutycycle can be set to amaximum ratio of 10:1. The sensing electronics allows to use the actuators as a button, which can be pressed by a human finger. It uses the inherent sensing capability of the DEA. Measurement is based on the change of the actuators capacitance under an applied finger pressure by integrating the charge current. To analyse the input either the tactile signal it self is used or an additional pulse is supplied to the actuators. An on-board TI MSP430 microcontroller on the control electronics regulates the interrelationship of button input and tactile output signals. Furthermore it allows changing the pattern of the tactile feedback depending on the users interaction. Even if there alised system works selfsustaining for demonstrating a tactile UI, a wireless link is provided. It can be used to visualize the input signals and manually control the outputs as well as to configure the mobile device, via a LabView Virtual Instrument (VI) running on a PC.

In this report we developed an algorithm that robustly selects faceskin. The algorithm has been tested on a set of challenging sequences. It is robust to partial occlusions, rotation of the head and spectrum changes of the illumination.

This report is about an internship which was part of a project that aims to develop a Luminescent Solar Concentrator (LSC) for commercial use. In the design of the LSC a wavelength selective mirror is used, in this case in the form of a Cholesteric Liquid Crystal (CLC) layer. The usage of this filter increases the efficiency of the system. To optimize the design of the LSC, a computer program has been adapted to simulate the behavior of the CLC. The calculations match the experiment and can be used to predict the Stokes parameters of there flected and the transmitted light. The results have been used tomake design decisions for the CLC.

A relative high power in the alpha band (8 - 13Hz) at a particular EEG position is believed to indicate an active inhibitory state of the corresponding cortical site. According to this hypothesis an active inhibitory state corresponds to a lower engagement of the cortical site and is accompanied by a higher engagement of other sites (possibly neighboring ones). In this project the influence of a repetitive visual stimulation on the alpha band was investigated. A special attention was paid to the difference between the individual alpha frequency and alpha power before and after the stimulation. Data was analyzed by using the matching pursuit time-frequency distribution that provides better resolution in time and frequency than STFT or Wigner-Ville transforms.

Research in Electroencephalogram (EEG) based Brain-Computer Interfaces (BCIs) has been considerably expanding during the last few years. Such an expansion owes to a large extent to the multidisciplinary and challenging nature of BCI research. Signal processing undoubtedly constitutes an essential component of a BCI system since from the EEG acquisition to the translation of brain activity into meaningful commands, multivariate signal processing algorithms are intensively applied. In this tutorial, the basic BCI concepts, EEG monitoring, BCI operation, the electrophysiological sources of BCI control, future directions, and ambitions are introduced. The main BCI types, namely motor imagery (ERD/ERS), steady state visual evoked potentials (SSVEP), and P300 based BCIs are presented along with practical application examples.The EEG processing for BCI applications is then described in depth. The multivariate nature of the EEG combined with the neuroscience knowledge on hemispheric brain specialization are advantageously taken into account to derive spatial filters (i.e. acrossthe EEG electrodes) to analyze the patterns resulting from motor imagery, visual evoked potentials, and the P300 paradigm.

The ion emission of a Sn-based discharge produced extreme ultraviolet producing plasma is characterized with the combined use of different time-of-flight techniques. An electrostatic ion spectrometer isemployed to measure the average charge distribution of the emitted Sn ions. A dedicated Faraday cup configuration is used to measure thetotal ion flux from the source for different discharge energies.High-energy Sn ions emitted by the plasma with energies up to 100keV have been identified. The number of high-energy ions increasesfor higher electrical input energy into the plasma while the signalassociated with the expanding plasma ions does not show such depen-dence. The ion energy distribution for a bulk of detected ions iscalculated based on the Faraday cup measurements and compared withtheoretical plasma expansion dynamics.

A fabric substrate is described for electronic textile with robust interwoven connections between the conductive yarns in it. The fabric's robustness, as a function of the electrical reliability of its conductive yarn connections, is shown to hold over large deformations.This fabric is then used to create an LED based photonic textile display. Finally, we show an example of an application that could make use of such a photonic textile system.

The proposed method simultaneously reconstructs activity and attenuation distribution of SPECT scans without usage of additional transmission scans. Moreover, in contrast to other approaches, it effectively prevents cross-talk artefacts by using a-priori atlas data and by labelling each organ with homogeneous attenuation values. The method generates a 3D-shape model of the patient and, in order to improve overall consistency between measured and estimated SPECT sinogram, modifications to the activity- and attenuation estimation are performed iteratively. Several reconstructions of patient and simulated SPECT data were investigated and reliable convergence behaviour as well as good agreement with reference images could be observed.

The amount of information present in HRTFs and the required processing capabilities for real-time and inter-active binaural rendering have long been a challenge for many applications for binaural rendering. More recently, parametric methods to capture the perceptually-relevant information from HRTFs have been developed. By means of extracting perceptually-relevant attributes from HRTF pairs, binaural rendering can be performed at lower complexity compared to the employment of HRTF convolution. Furthermore, parameter-based binaural rendering can be effiently integrated with parametric audio coders. Last but not least, parametric spatial processing can be used to provide a more convincing spatial reproduction for conventional stereo signals. This paper provides an overview of the perceptual consequences and limitations of HRTF parameterization, its applications, and relevant standardization efforts.

Experiments were conducted to measure perceptual changes in sharpness and contrast due to two environmental factors: viewing distance and ambient illumination. A field study was completed in two retail stores in which television customers were polled about image quality at long and short viewing distances. The study identified sharpness, brightness, and contrast as the perceptual attributes most influenced by changes in viewing distance. Subsequently, a viewing experiment was conducted in the laboratory in which the sizes of just noticeable differences (JNDs) of sharpness, black level, and white level were measured at different viewing distances and ambient illumination levels. The experiment used a two up, one down staircase method with a reference to detect thresholds. It was found that sensitivity to sharpness decreased with longer viewing distance and was unaffected by ambient illumination, and sensitivity to black level decreased with either increased distance or increased illumination. Sensitivity to white level was not significantly affected by either factor. These results may be used to select display settings or design parameters to suit different viewing situations.

A new method using a thin-film multilayer filter is described to couple light from high-power LEDs into a thin light guide such as an LCD backlight. Light emitted below the critical angle is reflected back to the LED and recycled. Large-angle emitted light passes the filter and is transported by total internal reflection in the light guide. The light guide can be as thin as 0.3mm for an LED of 1x1mm2, and the best coupling efficiency is estimated to be 82%. With this approach, a backlight system can be greatly simplified but also compactcollimators can be realized. In this paper the optical design and testing of the filter is described, and a 1mm thick, 6.5mm diameter collimator is presented. Measurements on prototypes show good agreement with the designed characteristics.

We investigate the potential to enhance breast cancer event predictors by exploiting subtype information. We do this with a two-stage approach that first determines a sample's subtype using a recent module-driven approach, and secondly constructs a subtype-specific predictor to predict a metastasis event within five years. Our methodology is validated on a large compendium of microarray breast cancer datasets,including 43 replicate array pairs for assessing subtyping stability. Note that stratifying by subtype strongly reduces the training set sizes available to construct the individual predictors, which may decrease performance. Besides sample size, other factors likeunequal class distributions and differences in the number of samplesper subtype, easily obscure a fair comparison between subtype-specific predictors constructed on different subtypes, but also between subtype specific and subtype a-specific predictors. Therefore, we constructed a completely balanced experimental design, in which none ofthe above factors play a role and show that subtype-specific eventpredictors clearly outperform predictors that do not take subtype information into account.

Appropriate design of the interaction between humans and robots will be a crucial factor for the acceptance of new robotic products. Apromising approach is to equip robots with life-like and social characteristics. A coherent personality expressed through behavior can help users to understand and predict the behavior of a robotic appliance. In this paper, we describe existing design approaches and arguethat an integrated design process is needed.

The goal of dry electrode development activity within the WP2 is tobuild a dry electrode prototype for brain wave sensing that is comfortable for the user and provides sufficient signal quality. The electrodes are to be utilized in BCI applications, namely Steady-StateVisually Evoked Potential (SSVEP),Event Related Synchronization andDe-synchronization (ERD/ERS),and P300 based BCIs. Due to the statusof the dry electrode technology and our non-encouraging results onthe evaluation of the contactless dry sensors we re-focused our efforts in developing an EEG system using dry electrodes that have galvanic contact to the human scalp. The first goal we set is to reliably detect the alpha brain rhythm (brain waves in the range from 8 to12Hz) as these brain waves are the most prominent ones in the EEG spectrum.The outcome of the evaluation presented here is that the signal quality of dry electrodes is sufficient to reliably measure alpha brainactivity. This is con-firmed through user studies with the medicallycertified amplifier - Mobi from TMSi. However, due to the skin contact problems and high input impedance, reported in the deliverable,robustness of dry-electrode (in combination with the amplifier) hasto be further improved. In particular, the dry electrode design andamplifier front end have to be further optimized.The robustness of the dry electrode-amplifier combination has to befurther improved to achieve a stable signal and reliable performancewhen measuring brain waves of people with long and thick hair. Thefollowing directions for further developments are envisioned:- Optimization of dry electrode design, focusing on- electrode material, i.e., using “bio-approved” materials such asgold and silver/silver-chloride used in this deliverable that willenable low impedance to the skin- number of pins to achieve good contact and increase the comfort- Optimization of amplifier front-end to cope with variation in input impedance- Optimize existing amplifier technology for usage with the developed dry electrodes.

It is well known that for quantitative analysis of XPS results theeffective take-off angle of the electrons is an important parameter.In the report is shown that the effective take-off angle i n PHI Quantera systems deviates significanlty from the set value. This is NOT a consequence of inadequate alignment of the detector but an intrinsic effect, caused by the relative large entrance angle of the detectorThe report present accurate measurements of the so-called detec-tion profile in PHI Quantera systems. It is shown how, making use ofthe experimentally obtained detection profile,the effective take-offangle can be calculated as a function of the set take-off angle.A few examples are presented demonstrating the relevance of the correction for the analysis of small angle XPS experiments.