Body sensor network for in-home personal healthcare

A body sensor network solution for personal healthcare under an indoor environment is developed. The system is capable of logging the physiological signals of human beings, tracking the orientations of human body, and monitoring the environmental attributes, which covers all necessary information for the personal healthcare in an indoor environment. The major three chapters of this dissertation contain three subsystems in this work, each corresponding to one subsystem: BioLogger, PAMS and CosNet. Each chapter covers the background and motivation of the subsystem, the related theory, the hardware/software design, and the evaluation of the prototype’s performance.

EXPERIMENTAL AND COMPUTATIONAL STUDIES OF ELECTROMAGNETIC CLOAKING AT MICROWAVES

An invisibility cloak is a device that can hide the target by enclosing it from the incident radiation. This intriguing device has attracted a lot of attention since it was first implemented at a microwave frequency in 2006. However, the problems of existing cloak designs prevent them from being widely applied in practice. In this dissertation, we try to remove or alleviate the three constraints for practical applications imposed by loosy cloaking media, high implementation complexity, and small size of hidden objects compared to the incident wavelength. To facilitate cloaking design and experimental characterization, several devices and relevant techniques for measuring the complex permittivity of dielectric materials at microwave frequencies are developed. In particular, a unique parallel plate waveguide chamber has been set up to automatically map the electromagnetic (EM) field distribution for wave propagation through the resonator arrays and cloaking structures. The total scattering cross section of the cloaking structures was derived based on the measured scattering field by using this apparatus. To overcome the adverse effects of lossy cloaking media, microwave cloaks composed of identical dielectric resonators made of low loss ceramic materials are designed and implemented. The effective permeability dispersion was provided by tailoring dielectric resonator filling fractions. The cloak performances had been verified by full-wave simulation of true multi-resonator structures and experimental measurements of the fabricated prototypes. With the aim to reduce the implementation complexity caused by metamaterials employment for cloaking, we proposed to design 2-D cylindrical cloaks and 3-D spherical cloaks by using multi-layer ordinary dielectric material (εr>1) coating. Genetic algorithm was employed to optimize the dielectric profiles of the cloaking shells to provide the minimum scattering cross sections of the cloaked targets. The designed cloaks can be easily scaled to various operating frequencies. The simulation results show that the multi-layer cylindrical cloak essentially outperforms the similarly sized metamaterials-based cloak designed by using the transformation optics-based reduced parameters. For the designed spherical cloak, the simulated scattering pattern shows that the total scattering cross section is greatly reduced. In addition, the scattering in specific directions could be significantly reduced. It is shown that the cloaking efficiency for larger targets could be improved by employing lossy materials in the shell. At last, we propose to hide a target inside a waveguide structure filled with only epsilon near zero materials, which are easy to implement in practice. The cloaking efficiency of this method, which was found to increase for large targets, has been confirmed both theoretically and by simulations.

An Experience-Driven Pedagogy for the Instruction of Software Testing in Computer Science

In the realm of computer programming, the experience of writing a program is used to reinforce concepts and evaluate ability. This research uses three case studies to evaluate the introduction of testing through Kolb's Experiential Learning Model (ELM). We then analyze the impact of those testing experiences to determine methods for improving future courses. The first testing experience that students encounter are unit test reports in their early courses. This course demonstrates that automating and improving feedback can provide more ELM iterations. The JUnit Generation (JUG) tool also provided a positive experience for the instructor by reducing the overall workload. Later, undergraduate and graduate students have the opportunity to work together in a multi-role Human-Computer Interaction (HCI) course. The interactions use usability analysis techniques with graduate students as usability experts and undergraduate students as design engineers. Students get experience testing the user experience of their product prototypes using methods varying from heuristic analysis to user testing. From this course, we learned the importance of the instructors role in the ELM. As more roles were added to the HCI course, a desire arose to provide more complete, quality assured software. This inspired the addition of unit testing experiences to the course. However, we learned that significant preparations must be made to apply the ELM when students are resistant. The research presented through these courses was driven by the recognition of a need for testing in a Computer Science curriculum. Our understanding of the ELM suggests the need for student experience when being introduced to testing concepts. We learned that experiential learning, when appropriately implemented, can provide benefits to the Computer Science classroom. When examined together, these course-based research projects provided insight into building strong testing practices into a curriculum.

Video Search: New Challenges in the Pervasive Digital Video Era

The explosion of multimedia digital content and the development of technologies that go beyond traditional broadcast and TV have rendered access to such content important for all end-users of these technologies. While originally developed for providing access to multimedia digital libraries, video search technologies assume now a more demanding role. In this paper, we attempt to shed light onto this new role of video search technologies, looking at the rapid developments in the related market, the lessons learned from state of art video search prototypes developed mainly in the digital libraries context and the new technological challenges that have risen. We focus on one of the latter, i.e., the development of cross-media decision mechanisms, drawing examples from REVEAL THIS, an FP6 project on the retrieval of video and language for the home user. We argue, that efficient video search holds a key to the usability of the new ”pervasive digital video” technologies and that it should involve cross-media decision mechanisms.

Semi-Automated Creation of Converged iTV Services: From Macromedia Director Simulations to Services Ready for Broadcast

While sound and video may capture viewers' attention, interaction can captivate them. This has not been available prior to the advent of Digital Television. In fact, what lies at the heart of the Digital Television revolution is this new type of interactive content, offered in the form of interactive Television (iTV) services. On top of that, the new world of converged networks has created a demand for a new type of converged services on a range of mobile terminals (Tablet PCs, PDAs and mobile phones). This paper aims at presenting a new approach to service creation that allows for the semi-automatic translation of simulations and rapid prototypes created in the accessible desktop multimedia authoring package Macromedia Director into services ready for broadcast. This is achieved by a series of tools that de-skill and speed-up the process of creating digital TV user interfaces (UI) and applications for mobile terminals. The benefits of rapid prototyping are essential for the production of these new types of services, and are therefore discussed in the first section of this paper. In the following sections, an overview of the operation of content, service, creation and management sub-systems is presented, which illustrates why these tools compose an important and integral part of a system responsible of creating, delivering and managing converged broadcast and telecommunications services. The next section examines a number of metadata languages candidates for describing the iTV services user interface and the schema language adopted in this project. A detailed description of the operation of the two tools is provided to offer an insight of how they can be used to de-skill and speed-up the process of creating digital TV user interfaces and applications for mobile terminals. Finally, representative broadcast oriented and telecommunication oriented converged service components are also introduced, demonstrating how these tools have been used to generate different types of services.

Marker-Based Embodied Interaction for Handheld Augmented Reality Games

This article deals with embodied user interfaces for handheld augmented reality games, which consist of both physical and virtual components. We have developed a number of spatial interaction techniques that optically capture the device's movement and orientation relative to a visual marker. Such physical interactions in 3-D space enable manipulative control of mobile games. In addition to acting as a physical controller that recognizes multiple game-dependent gestures, the mobile device augments the camera view with graphical overlays. We describe three game prototypes that use ubiquitous product packaging and other passive media as backgrounds for handheld augmentation. The prototypes can be realized on widely available off-the-shelf hardware and require only minimal setup and infrastructure support.

RFIDice - Augmenting Tabletop Dice with RFID

Augmented dice allow players of tabletop games to have the result of a roll be automatically recorded by a computer, e.g., for supporting strategy games. We have built a set of three augmented-dice-prototypes based on radio frequency identification (RFID) technology, which allows us to build robust, cheap, and small augmented dice. Using a corresponding readout infrastructure and a sample application, we have evaluated our approach and show its advantages over other dice augmentation methods discussed in the literature.

The Design of Networked Exertion Games

Incorporating physical activity and exertion into pervasive gaming applications can provide health and social benefits. Prior research has resulted in several prototypes of pervasive games that encourage exertion as interaction form; however, no detailed critical account of the various approaches exists. We focus on networked exertion games and detail some of our work while identifying the remaining issues towards providing a coherent framework. We outline common lessons learned and use them as the basis for generalizations for the design of networked exertion games. We propose possible directions of further investigation, hoping to provide guidance for future work to facilitate greater awareness and exposure of exertion games and their benefits.

Simulationsgestütztes Design eines Spritzgieß-Werkzeugeinsatzes mit kontur-angepasster Kühlung

Moderne generische Fertigungsverfahren für innengekühlte Werkzeuge bieten nahezu beliebige Freiheitsgrade zur Gestaltung konturnaher Kühlkanäle. Daraus resultiert ein erhöhter Anspruch an das Werkzeugengineering und die Optimierung der Kühlleistung. Geeignete Simulationsverfahren (wie z.B. Computational Fluid Dynamics - CFD) unterstützen die optimierte Werkzeugauslegung in idealer Weise. Mit der Erstellung virtueller Teststände können Varianten effizient und kostengünstig verglichen und die Kosten für Prototypen und Nacharbeiten reduziert werden. Im Computermodell des Werkzeugs erlauben Soft-Sensoren an beliebiger Position die Überwachung temperatur-kritischer Stellen sowohl im Fluid- als auch im Solidbereich. Der hier durchgeführte Benchmark vergleicht die Performance eines optimierten Werkzeugeinsatzes mit einer konventionellen Kühlung. Die im virtuellen Prozess vorhergesagte Zykluszeitreduzierung steht in guter Übereinstimmung mit realen Experimenten an den ausgeführten Werkzeugen.

Strahlschmelzen - LaserCUSING® - Integration im Werkzeug- und Formenbau

Die generativen Fertigungsverfahren haben längst ihren Platz in der Wertschöpfungskette neben konventionellen Prozessen eingenommen. Trotzdem müssen die Anwender immer wieder aufs Neue für die recht abstrakten Möglichkeiten und Chancen der Verfahren sensibilisiert werden. Querdenken kann oft schneller und effizienter zur erfolgreichen Problemlösung beitragen als traditionelle Schlüsselwege. Deshalb soll der Beitrag einige Kernpunkte ansprechen, die die additiven Verfahren in den Unternahmen – speziell das LaserCUSING® - als überaus sinnvolle Ergänzung des Technologieparks erachten. Neben der Herstellung von metallischen Prototypen geht der Vortrag insbesondere auf die Vielfalt der Effekte integrierbarer Kanäle in Formeinsätzen besonders des Spritzgusswerkzeugbaus ein.

Mechanische Eigenschaften und Bruchverhalten maskengesinterter Kunststoffbauteile

Das selektive Maskensintern von Kunststoffen ermöglicht die flächige Belichtung des Bauraums, wodurch sich konstante, von der zu belichtenden Geometrie/Fläche unabhängige Zykluszeiten pro Schicht ergeben. Durch den Einsatz eines, über dem Bauraum platzierten, Infrarotstrahlerfeldes wird eine Modifikation des verarbeiteten Polyamid 12-Pulvers mit einem Absorber, hier Flammruß, notwendig. Bisher konnte gezeigt werden, dass Prototypen sowie wärmeleitfähige Kunststoffbauteile hergestellt werden können. Im Rahmen dieses Beitrags sollen die mechanischen Eigenschaften von SMS-Bauteilen betrachtet werden. Die Beeinflussung der mechanischen Kennwerte, durch variierende Materialeigenschaften sowie unterschiedliche Prozessparameter, werden ebenso wie die Richtungs-, Temperatur- und Belastungsartabhängigkeit, bei konstanten Material- und Prozessparametern, untersucht. Zur Charakterisierung des Bauteilversagens wurden Methoden wie die Lichtmikroskopie und Rasterelektronenmikroskopie eingesetzt und Bruchmechanismen abgeleitet.

Produktentwicklung von Druckgussteilen

Die Produktentwicklung von Druckgussteilen kann flexibel, wirtschaftlich und schnell durch die Herstellung von RP-Unikaten und Metallabgüssen aus Keramikschalen realisiert werden. Dieser Weg eignet sich vor allem für komplexe Bauteile und macht eine Produkterprobung mit qualitativ deutlich verbesserter Aussagekraft trotz reduzierter Entwicklungskosten möglich. In Abgrenzung zum Sandguss, muss die Konstruktion der Bauteile nicht verändert werden. 
Durch eine gezielte Wärmebehandlung wird die Vergleichbarkeit der mechanischen Eigenschaften von Prototypen zu späteren Serienteilen möglich. Technisch sinnvolle Änderungen sind leicht und flexibel realisierbar, da werkzeuglos gefertigt wird. Für unerreichbare Hohlräume und Hinterschnitte kann in diesem Verfahren mit Keramikkernen als Einleger gearbeitet werden. Auch diese Kerne können werkzeuglos hergestellt werden. Ein Verzicht auf technisch Sinnvolles aus Kostengründen ist damit hinfällig.
In der Konstruktion ergeben sich neue Freiheitsgrade, so dass Ziele im Leichtbau, die Einsparung von Verbindungstechnik oder die erhöhte Materialeffizienz realisierbar werden. Die so entwickelten Bauteile sind insgesamt qualitativ hochwertiger und bilden die technischen Anforderungen bestmöglich ab. Damit kann die für die Erprobung benötigte Zahl der Prototypen verringert werden. 
Je komplexer die Geometrie der Bauteile, je stärker kommen die beschriebenen Effekte zum Tragen. Diese Aussage gilt für die Produktentwicklung und für Kleinserien, die herkömmlich zu teuer und zu schwer im Druckguss oder Schmiedeverfahren produziert werden

Aufbau hochfunktionaler Intralogistik-Knoten mittels kleinskaliger Module als Cognitive Conveyor

Kleinskalige, multifunktionale Module haben ein hohes Potential bei der wirtschaftlichen und flexiblen Gestaltung intralogistischer Systeme mit hoher Funktionalität. Durch dezentrale Steuerung und eigener Intelligenz der Module ist das System frei skalierbar und der Installationsaufwand wird minimiert. Mittels eines neuartigen Konzeptes der Datenkommunikation für Stetigförderer erfolgt der Informationsaustausch drahtlos mit Hilfe optoelektrischer Elemente. Die Kleinskaligkeit der Transportmodule gegenüber der Transporteinheit im Zusammenhang mit dem Steuerungskonzept erlaubt eine selektive Beschaltung der Module nach Bedarf und damit eine optimierte Energieausnutzung im Betrieb. Prototypen auf Basis von Schwenkrollen mit integrierter Antriebstechnik und Steuerung lassen das Potential des Prinzips erkennen. Das neu entwickelte Konzept der Schrägscheibe hilft bei der anspruchsvollen Integration der Antriebstechnik in das Modul durch das Prinzip der koaxialen Aktoren. Durch omnidirektionalen Funktionsumfang der Module entsteht im Zusammenschluss zu einer Modulmatrix ein hochflexibel einsetzbares Intralogistik-Modul. Die Vernetzung dieser hochfunktionalen Knoten durch einfache Fördertechnik bietet die Möglichkeit einfacher Planung flexibler Logistiksysteme.

A tutorial on data-driven methods for statistically assessing ERP topographies

Dynamic changes in ERP topographies can be conveniently analyzed by means of microstates, the so-called "atoms of thoughts", that represent brief periods of quasi-stable synchronized network activation. Comparing temporal microstate features such as on- and offset or duration between groups and conditions therefore allows a precise assessment of the timing of cognitive processes. So far, this has been achieved by assigning the individual time-varying ERP maps to spatially defined microstate templates obtained from clustering the grand mean data into predetermined numbers of topographies (microstate prototypes). Features obtained from these individual assignments were then statistically compared. This has the problem that the individual noise dilutes the match between individual topographies and templates leading to lower statistical power. We therefore propose a randomization-based procedure that works without assigning grand-mean microstate prototypes to individual data. In addition, we propose a new criterion to select the optimal number of microstate prototypes based on cross-validation across subjects. After a formal introduction, the method is applied to a sample data set of an N400 experiment and to simulated data with varying signal-to-noise ratios, and the results are compared to existing methods. In a first comparison with previously employed statistical procedures, the new method showed an increased robustness to noise, and a higher sensitivity for more subtle effects of microstate timing. We conclude that the proposed method is well-suited for the assessment of timing differences in cognitive processes. The increased statistical power allows identifying more subtle effects, which is particularly important in small and scarce patient populations.

Design and Impact of Awareness Functions – A Study about Social Media in Virtual Teams

The usage of social media in leisure time settings has become a prominent research topic. However, less research has been done on the design of social media in collaboration settings. In this study, we investigate how social media can support asynchronous collaboration in virtual teams and specifically how they can increase activity awareness. On the basis of an open source social networking platform, we present two prototype designs: a standard platform with basic support for information processing, communication and process – as suggested by Zigurs and Buckland (1998) – and an advanced platform with additional support for activity awareness via specialfeed functions. We argue that the standard platform already conveys activity awareness to a certain extent, however, that this awareness can be increased even more by the feeds in the advanced platform. Both prototypes are tested in a field experiment and evaluated with respect to their impact on perceived activity awareness, coordination and satisfaction. We show that the advanced design increases coordination and satisfaction through increased perceived activity awareness.