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Repository of the University of Hasselt containing publications in the fields of statistics, computer science, information strategies and material from the Institute for behavioural sciences.

Computer Sciences

Mostrando recursos 1 - 20 de 318

  1. Optimal Distribution of Computational Power in Free Viewpoint Interpolation by Depth Hypothesis Density Adaptation in Plane Sweeping

    GOORTS, Patrik; MAESEN, Steven; DUMONT, Maarten; ROGMANS, Sammy; BEKAERT, Philippe
    In this paper, we present a system to redistribute computational power in plane sweeping. Plane sweeping allows the generation of novel viewpoints of a scene by testing different depth hypotheses across input cameras. Typical plane sweeping approaches incorporate a uniform depth plane distribution to investigate different depth hypotheses to generate a depth map. When the scene consists of a sparse number of objects, some depth hypotheses do not contain objects and can cause noise and wasted computational power. Therefore, we propose a method to adapt the plane distribution to increase the quality of the depth map around objects and to...

  2. Robust Global Tracking Using a Seamless Structured Pattern of Dots

    JORISSEN, Lode; MAESEN, Steven; DOSHI, Ashish; BEKAERT, Philippe
    In this paper, we present a novel optical tracking approach to accurately estimate the pose of a camera in large scene augmented reality (AR). Traditionally, larger scenes are provided with multiple markers with their own identifier and coordinate system. However, when any part of a single marker is occluded, the marker cannot be identified. Our system uses a seamless structure of dots where the world position of each dot is represented by its spatial relation to neighboring dots. By using only the dots as features, our marker can be robustly identified. We use projective invariants to estimate the global position...

  3. Interactive Augmented Omnidirectional Video with Realistic Lighting

    MICHIELS, Nick; PUT, Jeroen; BEKAERT, Philippe; JORISSEN, Lode
    This paper presents the augmentation of immersive omnidirectional video with realistically lit objects. Recent years have known a proliferation of real-time capturing and rendering methods of omnidirectional video. Together with these technologies, rendering devices such as Oculus Rift have increased the immersive experience of users. We demonstrate the use of structure from motion on omnidirectional video to reconstruct the trajectory of the camera. The position of the car is then linked to an appropriate 360° environment map. State-of-the-art augmented reality applications have often lacked realistic appearance and lighting. Our system is capable of evaluating the rendering equation in real-time, by...

  4. Declarative Networking: Recent Theoretical Work on Coordination, Correctness, and Declarative Semantics

    AMELOOT, Tom
    We discuss recent theoretical results on declarative networking, in particular regarding the topics of coordination, correctness, and declarative semantics.

  5. Enhanced performance of polymer: fullerene bulk heterojunction solar cells upon graphene addition

    ROBAEYS, Pieter; Bonaccorso, Francesco; BOURGEOIS, Emilie; D'HAEN, Jan; DIERCKX, Wouter; DEXTERS, Wim; SPOLTORE, Donato; DRIJKONINGEN, Jeroen; LIESENBORGS, Jori; Lombardo, Antonio; Ferrari, Andrea C.; VAN REETH, Frank; HAENEN, Ken; Manca, Jean V.; Nesladek, Milos
    Graphene has potential for applications in solar cells. We show that the short circuit current density of P3HT (Poly(3-hexylthiophene-2,5-diyl):PCBM((6,6)-Phenyl C61 butyric acid methyl ester) solar cells is enhanced by 10% upon the addition of graphene, with a 15% increase in the photon to electric conversion efficiency. We discuss the performance enhancement by studying the crystallization of P3HT, as well as the electrical transport properties. We show that graphene improves the balance between electron and hole mobilities with respect to a standard P3HT:PCBM solar cell. (C) 2014 AIP Publishing LLC.

  6. SubwayPS: Towards Enabling Smartphone Positioning in Underground Public Transportation Systems

    Stockx, Thomas; Hecht, Brent; SCHOENING, Johannes
    mobile navigation; positioning; mobile devices; underground public transport; GPS; accelerometer

  7. Touch the 3rd Dimension! Understanding Stereoscopic 3D Touchscreen Interaction

    Colley, Ashley; Hakkila, Jonna; SCHOENING, Johannes; Daiber, Florian; Steinicke, Frank; Kruger, Antonio

  8. Attention as an Input Modality for Post-WIMP Interfaces Using the viGaze Eye Tracking Framework

    Giannopoulos, Ioannis; Schoening, Johannes; Kruger, Antonio; Raubal, Martin
    Eye tracking is one of the most prominent modalities to track user attention while interacting with computational devices. Today, most of the current eye tracking frameworks focus on tracking the user gaze during website browsing or while performing other tasks and interactions with a digital device. Most frameworks have in common that they do not exploit gaze as an input modality. In this paper we describe the realization of a framework named viGaze. Its main goal is to provide an easy to use framework to exploit the use of eye gaze as an input modality in various contexts. Therefore it provides...

  9. Raising Awareness on Smartphone Privacy Issues with SASQUATCH, and solving them with PrivacyPolice

    BONNE, Bram; LAMOTTE, Wim; QUAX, Peter; LUYTEN, Kris

  10. Overcoming interaction barriers in large public displays using personal devices

    Cheung, Victor; Watson, Diane; VERMEULEN, Jo; Hancock, Mark; Scott D., Stacey
    This work presents a design space in which personal devices are used as a means to facilitate “socially safe”, ad-hoc interaction with large public displays. Unlike most existing work that focuses on facilitating content placement and transfer, this approach aims at minimizing the effort required to initiate, sustain, and withdraw from interaction with a large public display, and to communicate these capabilities to passersby. We identify barriers hindering this process, and offer advice on overcoming them based on existing work and our own experiences with these displays. We illustrate how this design concept can be applied, and motivate applications in...

  11. From today???s augmented houses to tomorrow???s smart homes: new directions from home automation research

    Mennicken, Sarah; VERMEULEN, Jo; Huang M., Elaine
    A considerable amount of research has been carried out towards making long-standing smart home visions technically feasible. The technologically augmented homes made possible by this work are starting to become reality, but thus far living in and interacting with such homes has introduced significant complexity while offering limited benefit. As these technologies are increasingly adopted, the knowledge we gain from their use suggests a need to revisit the opportunities and challenges they pose. Synthesizing a broad body of research on smart homes with observations of industry and experiences from our own empirical work, we provide a discussion of ongoing and...

  12. The Dark Patterns of Proxemic Sensing

    Boring, Sebatsian; Greenberg, Saul; VERMEULEN, Jo; Dostal, Jakub; Marquardt, Nicolai

  13. Quasi-classical description logic

    ZHANG, Xiaowang; LIN, Zuoquan
    In this paper, we present a paraconsistent description logic based on quasi-classical logic. Compared to the four-valued description logic, quasi-classical description logic satisfies all of the three basic inference rules (i.e., modus ponens, modus tollens and disjunctive syllogism) so that the inference ability of quasi-classical description logic is closer to that of classical logic. Quasi-classical description logic combines three inclusions (i.e., material inclusion, internal inclusion and strong inclusion) of four-valued description logic so that quasi-classical description logic satisfies the intuitive equivalence. Moreover, we develop a terminable, sound and complete tableau algorithm for quasi-classical description logic. As an important result, the...

  14. On the power of SPARQL in expressing navigational queries

    ZHANG, Xiaowang; VAN DEN BUSSCHE, Jan
    Navigational queries on graph databases return binary relations over the nodes of the graph. The calculus of relations, popularized by Tarski, serves as a natural benchmark for first-order navigational querying. Recently, nested regular expressions (nre's) have been proposed to extend navigational querying to resource description framework graphs, i.e. ternary relations. This paper investigates the expressiveness of nre's and their relationship to basic SPARQL queries. An elegant proof is given to the effect that nre queries are already expressible as basic SPARQL queries. This result takes exception of nre's involving Kleene star (transitive closure), but on the other hand it holds...

  15. On the completeness of the semigraphoid axioms for deriving arbitrary from saturated conditional independence statements

    GYSSENS, Marc; Niepert, Mathias; Van Gucht, Dirk
    Conditional independence (CI) statements occur in several areas of computer science and artificial intelligence, e.g., as embedded multivalued dependencies in database theory, disjunctive association rules in data mining, and probabilistic CI statements in probability theory. Although, syntactically, such constraints can always be represented in the form I(A, B vertical bar C), with A, B, and C subsets of some universe S, their semantics is very dependent on their interpretation, and, therefore, inference rules valid under one interpretation need not be valid under another. However, all aforementioned interpretations obey the so-called semigraphoid axioms. In this paper, we consider the restricted case...

  16. I-TRAVLE training to improve upper limb function in MS and stroke: a cohort study

    MARIS, Anneleen; DE WEYER, Tom; CONINX, Karin; Geers, R.; Seelen, H.; Stupar, S.; Kerkhofs, L.; Lemmens, M.; Truyens, V.; FEYS, Peter

  17. Surgical Safety Checklists : an Update

    Bergs, Jochen; Hellings, Johan; CLEEMPUT, Irina; SIMONS, Pascale; ZUREL, Ozhan; VERTRIEST, Sonja; VANDIJCK, Dominique
    Surgical safety checklists aim to improve patient safety by prompting the attention of the surgical team towards critical steps during the operation. The checklist's items are aimed to improve compliance with proven interventions, and to facilitate multidisciplinary communication and teamwork. Based on the current literature, corroborated by systematic reviews and meta-analysis, surgical safety checklists have a positive impact on communication and reduce postoperative complications including mortality. However, despite their effectiveness, the implementation of these checklists is not straightforward. Several determinants leading to behaviour were checklists are checked but not properly executed have been highlighted. As surgical safety checklists are in...

  18. Real-time, Adaptive Plane Sweeping for Free Viewpoint Navigation in Soccer Scenes

    Goorts, Patrik
    In this dissertation, we present a system to generate a novel viewpoint using a virtual camera, specifically for soccer scenes. We demonstrate the applicability for following players, freezing the scene, generating 3D images, et cetera. The method is demonstrated and investigated for 2 camera arrangements, i.e. a curved and a linear setup, where the distance between the cameras can be up to 10 meters. The virtual camera should be located on a position between the real camera positions. The method is designed to be automatic and has high quality results using high performance rendering. We presented an image-based method to generate the novel...

  19. ReHoblet – A Home-Based Rehabilitation Game on the Tablet

    VANDERMAESEN, Marijke; ROBERT, Karel; LUYTEN, Kris; CONINX, Karin
    We present ReHoblet; a physical rehabilitation game on tablets, designed to be used in a residentialsetting. ReHoblet trains two gross motor movements of the upper limbs by lifting (up-down) and transporting (leftright) the tablet to control a simple platform game. By using its accelerometers and gyroscope, the tablet is capable of detecting movements made by the user and steer the interaction based on this data. A formative evaluation with five Multiple Sclerosis (MS) patients and their therapists showed high appreciation for ReHoblet. Patients stated they liked ReHoblet not only to improve their physical abilities, but to train on performing technology-related tasks....

  20. Quality of service in mobile ad hoc networks, carrying multimedia traffic

    NYAMBO, Benny; Janssens, Gerrit K.; Lamotte, Wim
    Mobile ad hoc networks (MANETs) have become an integral part of the ubiquitous computing and communication environment, providing new infrastructure for multimedia applications such as video phone, multimedia-on-demand, and others. In order to access multimedia information in a MANET, Quality of Service (QoS) needs to be considered, such as high success rate to access multimedia data, bounded end-to-end delay, security and others. Factors, like delay and jitter, bandwidth and throughput, are studied that affect quality of service in wireless mobile ad hoc networks. Various Quality of Service architectures on IEEE 802.11-based mobile ad hoc networks are discussed, concentrating on architectures...

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