I have completed my PhD in the field of intermediate energy physics: I have numerically calculated experimental properties using a QCD-string model. Part of the project consisted of lecturing undergraduate students as a teaching assistant on several advanced courses.
Subsequently I started my work at Philips Research in the domain of multimedia applications. Gradually I have shifted my interest into creating new user interaction concepts, and confronting them with users. Currently I'm working as a Senior Scientist on physiological tests for new concepts at Philips Research.
Abstract: Digital video capturing is getting popular with the decreasing price of camcorders and the increasing availability of devices with embedded video cameras such as digital-still cameras, mobile phones and PDAs. While a raw home video is considered as visually non-appealing, having multiple recordings of the same event provides the opportunity to combine audio and video segments from different cameras for improving quality and aesthetics. Mixing content from different recordings requires precise synchronization among the recordings. In most present applications, synchronization is done manually and considered as a very tedious task. In this paper, we propose a novel automated synchronization approach based on detecting and matching audio and video features extracted from the recorded content. We assess experimentally three realizations of this approach on a common data set and make recommendations on the usability of the different realizations in practical use cases. The realizations have no limitations on the number and movement of the cameras. Moreover, they are robust against various ambient noises and audio-visual artifacts occurring during the recordings.
Abstract: The QCD-string model for baryons derived by Simonov and used for the calculation of baryon magnetic moments in Ref. [1] is extended to include also perturbative gluon and meson exchanges. The mass spectrum of the baryon multiplet is studied. For the meson interaction either the pseudoscalar or pseudovector coupling is used. Predictions are compared with the experimental data. Besides these exchanges the influence of excited quark orbitals on the baryon ground state are considered by performing a multichannel calculation. The nucleon-Δ splitting increases due to the mixing of higher quark states while the baryon magnetic momenta decrease. The multichannel calculation with perturbative exchanges is shown to yield reasonable magnetic moments while the mass spectrum is close to experiment.
Abstract: An effective quark Lagrangian is derived from first principles through bilocal gluon field correlators. It is used to write down equations for baryons, containing both perturbative and nonperturbative fields. As a result one obtains magnetic moments of octet and decuplet baryons without introduction of constituent quark masses and using only string tension as an input. Magnetic moments come out on average in reasonable agreement with experiment, except for nucleons and Sigma−. The predictions for the proton and neutron are shown to be in close agreement with the empirical values once we choose the string tension such to yield the proper nucleon mass. Pionic corrections to the nucleon magnetic moments have been estimated. In particular, the total result of the twobody current contributions are found to be small. Inclusion of the anomalous magnetic moment contributions from pion and kaon loops leads to an improvement of the predictions.
Abstract: To help consumers dealing with their growing amount of home video, we have developed the Edit While Watching (EWW) system. It is designed to automatically create an edited version of a home video and then allow the users to modify and refine it in an easy, intuitive and lean-back way. To measure the ease of use, ease of learning, and effectiveness of the EWW system, we have performed a use test by means of giving participants tasks to do and interviewing them. The use test was focused on four main aspects: functionality, usability, pleasantness, and user satisfaction. The test was performed with eight participants, and was located in the Philips HomeLab, which resembles a home environment as much as possible. The results show that the system provides rather limited control of the editing functions, and the overview of the video material is unsatisfactory. However, the participants judged the system as an easy to learn and easy to use video editing tool. They expressed their pleasure in working with it.
Abstract: In recent years, more and more people capture their experiences in home videos. However, home video editing still is a difficult and time-consuming task. We present the Edit While Watching system that allows users to automatically create and change a summary of a home video in an easy, intuitive and lean-back way. Based on content analysis, video is indexed, segmented, and combined with proper music and editing effects. The result is an automatically generated home video summary that is shown to the user. While watching it, users can indicate whether they like certain content, so that the system will adapt the summary to contain more content that is similar or related to the displayed content. During the video playback users can also modify and enrich the content, seeing immediately the effects of their changes. Edit While Watching does not require a complex user interface: a TV and a few keys of a remote control are sufficient. A user study has shown that it is easy to learn and to use, even if users expressed the need for more control in the editing operations and in the editing process.
Abstract: Distinguishing children from adults in digital images is beneficial for enabling ambient intelligent applications. For example, when an ambient intelligent shop window detects a child, it could adapt its content to the particular limitations and needs of children. This article presents a method to automatically detect children in digital images. The method is based on the fact that the size of a person's iris is practically constant after birth while the head grows as the person grows adult. Therefore adults can be distinguished from children based on the face/iris size ratio. The faces are detected using a standard Viola-Jones face detection technique. The irises are found and measured by using iterative Canny edge detection and a modified circular Hough transform. Our results show an accuracy of over 80% when tested on a set of 289 real life photographs of frontal faces.
Abstract: Having entered the terabyte consumer storage era and sailing towards petaand hexa- storage, we still have only adequate tools for browsing megabytes of stored video information. Movie-in-a-minute is a summarization method that generates a short video preview composed of automatically selected portions of a video recording. It aims at conveying key aspects of a program and its story in an efficient and entertaining manner. In doing so, movie-in-a-minute allows easy management of hundreds of hours of stored video programs. In this paper we present an approach to generate movie-in-a-minute previews based on automatic video and audio content analysis. The method has been formalized using a knowledge-explicit approach, implemented and tested as a new feature for consumer digital recorders.
Abstract: In this thesis we have explored the baryon wave function obtained from the QCD-Lagrangian by the field correlator method. Using this method, the gluonic degrees of freedom have been integrated out and an effective Lagrangian was obtained. In the lowest order of the approximation scheme, neglecting gluon and meson exchanges, the resulting baryon wave function is given by a product of three independent single-quark orbitals, each satisfying the Dirac-like equation with a nonlocal kernel. This kernel is the nonlocal quark mass operator M(x,y), represented by the QCD string and containing both confinement and CSB. We have used the baryon wave function obtained in this way, to calculate the magnetic moments of the lowest baryon octet and decuplet representation of the SU(3)-flavor group. Reasonable agreement with experimental baryon magnetic moments was obtained for a string tension of while the baryon masses were in the correct region without need for introduction of constituent quark masses. Since the confining nonlocal operator M(x,y) does not involve any spin-dependent interactions, the first stage of the model does not account for the mass splitting between the baryon octet and decuplet. We have subsequently improved this omission by considering in addition perturbative one-gluon and pseudoscalar meson exchanges. For the interaction of the pseudoscalar meson with the quark both the pseudoscalar and the pseudovector coupling have been investigated. The effects of excited single-quark orbitals on the baryon ground state are also considered. The calculation is performed by using all possible combinations of four single-quark orbitals for the u,d-quark and the s-quark to build different three-particle states. The resulting states are used as a basis to diagonalize the Hamiltonian. As a result, the predictions on the mass spectrum and the magnetic moments of the quarks improve. The best overall agreement is found when the string tension is lowered to and a pseudovector coupling of the pseudoscalar meson to the quark is used.
Abstract: The master thesis investigates several aspects of elementary spin-3/2 particles. New consistent couplings of the Δ-resonance are formulated. The Kamerlingh Onnes price was awarded for exceptional quality.
