69 research outputs found
Telling your story: autobiographical metadata and the semantic web
No full textGiven the current explosion of user-generated content driven by the ever-decreasing price of sensing and storage hardware the dream of capturing and archiving the entirety of a human life is slowly being realised. The Semantic Web, a discipline of Computer Science, aims to support the sharing and interoperation of knowledge using the Web’s infrastructure. This thesis aims to roadmap a framework utilising the principles and technologies underpinning the Semantic Web, enabling the vision of global knowledge sharing, in an open and policy aware manner, with the end aim of supporting a network for the exploitation of personal information. This sharing is facilitated through the adoption of a lingua franca, shared conceptualisations for domain knowledge, and some core design principles. The main focus of Semantic Web research has been the development of a web-scale knowledge-base whereby information is stored and exposed in a machine-readable format with the ultimate aim of aggregating information from disparate sources, allowing for statements to be contextualised with respect to others culminating in a web-scale knowledge resource accessible through standard protocols.The current popularity of social computing – Web 2.0 – where users post personal information to online communities is eluding to the fact that information, linked and shared within a social-context presents added value to the end-user. Given the sensitive nature of personal information, one may not wish to expose all of the information about them self to the World Wide Web, but may wish to benefit by linking to knowledge residing on this shared resource. This ability to store personal information privately, in ones own personal web-space and not on a third party server, whilst at the same time connecting to the publicly available information is presented as key challenge facing the Computer Science community today. Specific information pertaining to one aspect of a user’s activities, such as their picture taking habits or their geographic log, may not present a detailed account of a user’s actions, but as more information is pushed into the public domain and aggregation technologies mature individuals and their day-to-day activities will be easier to track. As more and more of our personal lives are pushed into the public domain, the notion of an online-persona is becoming more and more applicable to the average person.This thesis presents an infrastructure for the capturing and archival of autobiographical metadata, whereby information from multiple sensors is aggregated and stored in a personal Lifelog. The surrender of digital identity has become commonplace, for purposes ranging from commerce, marketing, social networking, government, receipt of services, travel or security, Lifelogging has the potential to reaffirm the individual’s control of his or her own digital identity. The Lifelog is a constructed identity that outweighs the others simply by weight of evidence, complexity and comprehensiveness. This thesis presents an infrastructure for the capture and exploitation of personal metadata to drive research into context aware systems. The aim is to expose ongoing research in the areas of capture of personal experiences, context aware systems, multimedia annotation systems, narrative generation, all set in the context of enabling and supporting the Semantic Web Vision. The thesis details the work underway towards the goal of creating a multi-domain contextual log, and is followed by a discussion of how such a log can be used to drive the development of detailed Lifelog and an investigation into the amount of personal information being pushed into the public domain.<br/
Demetrius Author of the treatise 'On style'
No full textBadian, Ernst (Cambridge, MA), Schütrumpf, Eckart E. (Boulder, CO), Günther, Linda-Marie (Munich), Meier, Mischa (Bielefeld), Strothmann, Meret
(Bochum), Mehl, Andreas (Halle/Saale), Will, Wolfgang (Bonn), Eck, Werner (Cologne), Makris, Georgios (Bochum), Rist, Josef (Würzburg) et al.,
“Demetrius”, in: Brill’s New Pauly, Antiquity volumes edited by: Hubert Cancik and , Helmuth Schneider. Consulted online on 13 May 2017
First published online: 2006
First print edition: 9789004122598, 2011051
Efficiency of Exciton and Charge Carrier Photogeneration in a Semiconducting Polymer
No full textEuan Hendry, Juleon M. Schins, L. P. Candeias, L. D. A. Siebbeles, and Mischa Bonn, Physical Review Letters, Vol. 92, article 196601 (2004). "Copyright © 2004 by the American Physical Society."We determine the efficiencies for the formation of excitons and charge carriers following ultrafast photoexcitation of a semiconducting polymer (MEH-PPV). The simultaneous, quantitative determination of exciton and charge photoyields is achieved through subpicosecond studies of both the real and the imaginary components of the complex conductivity over a wide frequency range. Predominantly excitons, with near-unity quantum efficiency, are generated on excitation, while only a very small fraction (<10-2) of free charges are initially excited, consistent with rapid (∼100 fs) hot exciton dissociation. These initial charges are very short lived, decaying on subpicosecond time scales
Ultrafast charge generation in a semiconducting polymer studied with THz emission spectroscopy
No full textEuan Hendry, Mattijs Koeberg, Juleon M. Schins, L. D. A. Siebbeles, and Mischa Bonn, Physical Review B, Vol. 70, article 033202 (2004). "Copyright © 2004 by the American Physical Society."We study the ultrafast charge generation in a semiconducting polymer (MEH-PPV) by measuring the radiated THz field after photoexciting the biased polymer with a femtosecond visible pulse. The subpicosecond temporal characteristics of the emitted wave reflects the ultrafast photoconductivity dynamics and sets an upper limit for charge generation of 200 fs following photoexcitation, and reveals the dispersive nature of charge transport in MEH-PPV. A comparison of the fields radiated from MEH-PPV and the well-characterized model semiconductor system (GaAs) allows for an accurate estimate of the quantum efficiency for charge generation in the polymer, found to be less than 1% . Both observations are consistent with ultrafast charge generation in semiconducting polymers through hot exciton dissociation
Demetrius Author of the treatise 'On style'
No full textBadian, Ernst (Cambridge, MA), Schütrumpf, Eckart E. (Boulder, CO), Günther, Linda-Marie (Munich), Meier, Mischa (Bielefeld), Strothmann, Meret
(Bochum), Mehl, Andreas (Halle/Saale), Will, Wolfgang (Bonn), Eck, Werner (Cologne), Makris, Georgios (Bochum), Rist, Josef (Würzburg) et al.,
“Demetrius”, in: Brill’s New Pauly, Antiquity volumes edited by: Hubert Cancik and , Helmuth Schneider. Consulted online on 13 May 2017
First published online: 2006
First print edition: 9789004122598, 2011051
The complex stacking disorder of Fe- and Ru-based 1,1′-(3,6-pyrazabolyl)metallocenes
No full text1,10-(3,6-Pyrazabolyl)ferrocene [Fc(BHpz)2] and the corresponding ruthenocene [Rc(BHpz)2] crystallize as order–disorder (OD) structures with layers of Pma(m) symmetry. Since the m[100] reflection and the a[010] glide reflection planes of adjacent layers do not overlap, given one layer, the adjacent layer can be placed in four distinct, but geometrically equivalent, positions. There are accordingly four polytypes of a maximum degree of order (MDO). One analyzed Fc(BHpz)2 crystal was composed of a mixture of the MDO1 polytype in four distinct orientations and the MDO3 polytype. A second crystal was essentially a single crystal of one out of two orientation of MDO3. In two analyzed crystals of Rc(BHpz)2, the MDO1 polytype (P-1) was the major polytype and was observed in four or two orientation states, respectively. Pronounced diffuse scattering is attributed to a complex disorder, which cannot be explained by simple growth models. One Rc(BHpz)2 crystal features additional peaks in the diffraction pattern attributed to fragments of MDO3
Simultaneous ultrafast probing of intramolecular vibrations and photoinduced charge carriers in rubrene using broadband time-domain THz spectroscopy
Full text linkMattijs Koeberg, Euan Hendry, Juleon M. Schins, Hendrik A. van Laarhoven, Cees F. J. Flipse, Klaus Reimann, Michael Woerner, Thomas Elsaesser, and Mischa Bonn, Physical Review B, Vol. 75, article 195216 (2007). "Copyright © 2007 by the American Physical Society."We determine the ultrafast frequency- and time-resolved complex dielectric responses of photoexcited, single-crystal rubrene in the frequency range of 10–30 THz (330–1000 cm−1) using ultrafast broadband THz spectroscopy. In this frequency range, we observe the response of both photogenerated mobile charges and intramolecular vibrational modes simultaneously, both of which vary with time after excitation. The data in conjunction with a theoretical model indicate a dynamic blueshift of the 15.5 THz phonon
Assessment of Lunar Positioning Accuracy with PECMEO Navigation Satellites
No full textMany low earth satellites use GNSS for orbit determination, both for operational purposes and post-facto scientific orbits. Using GNSS systems for Lunar navigation proves difficult, however, due to the signals being weak and having limited coverage. This thesis investigates, through numerical simulation, the usage of a constellation of Polar or Equatorial Medium Earth Orbit (PECMEO) satellites for Lunar navigation. The system is proposed as alternative for orbit determination using ground-based observations, making navigation of the spacecraft more autonomous, without limitations on the number of receivers. A navigation constellation of 9 satellites at an orbital radius of 14 000 km is designed by minimizing the Geometric Dilution of Precision (GDOP). The resulting Pareto front of optimum solutions consists of two distinct groups of constellations. Firstly, constellation with lower mean GDOP and higher maximum GDOP have two orbits approximately orthogonal to the ecliptic plane, while the third orbit is in the ecliptic plane. Meanwhile, a second group of solutions with slightly higher mean GDOP, but significantly lower maximum GDOP are found for constellation with one plane approximately orthogonal to the ecliptic plane, while the remaining two planes have an inclination of near 45 degrees. One of the latter group of solutions has been chosen for the system for its lower maximum GDOP. The effect of omitting observations passing through the ionosphere is investigated to determine if there is a need to obtain observations at multiple frequencies to allow for ionospheric corrections. Omitting those observations results in a slightly increased GDOP right before and after a satellite passes behind Earth, of up to 56.4%. However, only 13.9% of the samples are effected, making the overall effect rather small. The positioning accuracy of the system is assessed by simulating pseudorange and carrier phase observations, and solving these with point position and kinematic least squares methods. Two main error contributions on the solutions are caused by observation noise and navigation satellite ephemerides errors. A solution for observations without ephemeris error, a mean 3-dimensional position error of 3.3m is obtained. A solution for noiseless observations yields a mean 3-dimensional position error of 26.8m. Finally, the solution obtained from observations with all simulated errors results in a mean 3-dimensional position error of 27.0m, to which the ephemeris errors are thus the main contributors, despite optimistic assumptions on their magnitude. The observed accuracy shows that the system is a viable navigation method for Lunar spacecraft.Aerospace Engineerin
Digital Delft Blue, a new approach
No full textRoyal Delft is the oldest manufacturer of delftware that is still producing Delft Blue using traditional techniques up to this day. At the core of their company lies the craftsmanship of producing delftware by hand, from creating the moulds to hand-painting each piece of Delft Blue. With a fast moving industry, Royal Delft needs to innovate constantly to keep their market presence. By modernising their designs and collaborating with external companies, they manage to create contemporary Delft Blue.Apart from hand-painting and transfers, Royal Delft wanted to look for new possibilities to decorate delftware. Through a collaboration with TU Delft, a first prototype was made with a lot of potential, which let to this master thesis. This thesis presents an improved design of a Delft Blue painting robot with a working demonstrator. This demonstrator is able to autonomously decorate tiles with different techniques, ranging from creating personalised anniversary tiles to gold lustering and painting large tableaus. The consistency of the painting robot is achieved by analysing the surface of each tile and adjusting the brush accordingly. The robot uses the traditional brush and paint as hand-painted delftware, meaning that the robot is able to change brushes and dip the paint automatically. The benefit of this production method is the quick personalisation and cost efficiency compared to other production methods. As hand-painted products are easy to customise but very expensive, and transfer products require a large batch, robotic painting is a good alternative that is both easy to customise and affordable. An attempt was made to expand the product range to 2.5D products, such as plates and dishes. After scanning the surface and writing the software to follow the surface, the results lacked consistency due to the accumulation of uncontrolled variables, making 2.5D painting not viable with this configuration. Finally, a design was presented for implementing the robot into the Royal Delft production process. The concept was validated with a showcase product, a demonstration day in the museum and a discussion with the account managers of Royal Delft. The results were promising, and the robot could be a valuable addition to Royal Delft. Integrated Product Desig
Life estates
Full text linkLife Estates presents four of the author\u27s original short-stories along with an introductory essay which explains the author\u27s evolving aesthetic theories. The collection represents the author\u27s search for her voice as a fiction writer
- …
