Search results for " Software"

Representation of NURBS surfaces by Controlled Iterated Functions System automata

2019

Iterated Function Systems (IFS) are a standard tool to generate fractal shapes. In a more general way, they can represent most of standard surfaces like Bézier or B-Spline surfaces known as self-similar surfaces. Controlled Iterated Function Systems (CIFS) are an extension of IFS based on automata. CIFS are basically multi-states IFS, they can handle all IFS shapes but can also manage multi self-similar shapes. For example CIFS can describe subdivision surfaces around extraordinary vertices whereas IFS cannot. Having a common CIFS formalism facilitates the development of generic methods to manage interactions (junctions, differences...) between objects of different natures.This work focuses…

CSCL for NGO's Cross cultural Virtual Teams in Africa: An Ethiopian Children Advocacy Case Study against Exclusion and toward Facilitation of Express…

2005

This exploratory pilot study shows that NGO's involved in Children Advocacy through Arts in Africa are willing to use a groupware, meaning a computer supported collaborative learning (CSCL) environment. Innovative ideas and best practices among NGOs would be shared easily worldwide. Little scientific information is available to help them make a sound choice. This study suggests that some NGOs based in Ethiopia/Africa have specific needs which should translate in specific context analysis and interface development: 1) an intercultural approach to creativity, arts and innovation, and 2) emphasis should be placed on tools to facilitate asynchronous systematic conception and sharing of intra an…

Automatic Calibration of an Industrial RGB-D Camera Network Using Retroreflective Fiducial Markers

2019

This paper describes a non-invasive, automatic, and robust method for calibrating a scalable RGB-D sensor network based on retroreflective ArUco markers and the iterative closest point (ICP) scheme. We demonstrate the system by calibrating a sensor network comprised of six sensor nodes positioned in a relatively large industrial robot cell with an approximate size of 10 m × 10 m × 4 m . Here, the automatic calibration achieved an average Euclidean error of 3 c m at distances up to 9.45 m . To achieve robustness, we apply several innovative techniques: Firstly, we mitigate the ambiguity problem that occurs when detecting a marker at long range or low resolution by comparing the…

Hidden Pursuits: Evaluating Gaze-selection via Pursuits when the Stimuli's Trajectory is Partially Hidden

2018

The idea behind gaze interaction using Pursuits is to leverage the human's smooth pursuit eye movements performed when following moving targets. However, humans can also anticipate where a moving target would reappear if it temporarily hides from their view. In this work, we investigate how well users can select targets using Pursuits in cases where the target's trajectory is partially invisible (HiddenPursuits): e.g., can users select a moving target that temporarily hides behind another object? Although HiddenPursuits was not studied in the context of interaction before, understanding how well users can perform HiddenPursuits presents numerous opportunities, particularly for small interfa…

Concurrent Computing with Shared Replicated Memory

2019

Any concurrent system can be captured by a concurrent Abstract State Machine (cASM). This remains valid, if different agents can only interact via messages. It even permits a strict separation between memory managing agents and other agents that can only access the shared memory by sending query and update requests. This paper is dedicated to an investigation of replicated data that is maintained by a memory management subsystem, where the replication neither appears in the requests nor in the corresponding answers. We specify the behaviour of a concurrent system with such memory management using concurrent communicating ASMs (ccASMs), provide several refinements addressing different replic…

Area-Based Depth Estimation for Monochromatic Feature-Sparse Orthographic Capture

2018

With the rapid development of light field technology, depth estimation has been highlighted as one of the critical problems in the field, and a number of approaches have been proposed to extract the depth of the scene. However, depth estimation by stereo matching becomes difficult and unreliable when the captured images lack both color and feature information. In this paper, we propose a scheme that extracts robust depth from monochromatic, feature-sparse scenes recorded in orthographic sub-aperture images. Unlike approaches which rely on the rich color and texture information across the sub-aperture views, our approach is based on depth from focus techniques. First, we superimpose shifted …

A Taxonomy for App-Enabled Devices: Mastering the Mobile Device Jungle

2018

While the term application is known for a long time, what we now refer to as mobile apps has facilitated task-oriented, interoperable software. The term was initially only used for smartphones and tablets, but desktop software now is also referred to as apps. More important than the wording, however, is the trend towards app-enablement of many further kinds of devices such as smart TVs and wearables. App-enabled devices usually share some characteristics and developing apps is often similar. However, many complexities must be mastered: Device fragmentation and cross-platform app development already are challenging when only considering smartphones. When trying to grasp the field as a whole,…

Emphasizing visualization and physical applications in the study of eigenvectors and eigenvalues

2016

(Approximate) Low-Mode Averaging with a new Multigrid Eigensolver

2015

We present a multigrid based eigensolver for computing low-modes of the Hermitian Wilson Dirac operator. For the non-Hermitian case multigrid methods have already replaced conventional Krylov subspace solvers in many lattice QCD computations. Since the $\gamma_5$-preserving aggregation based interpolation used in our multigrid method is valid for both, the Hermitian and the non-Hermitian case, inversions of very ill-conditioned shifted systems with the Hermitian operator become feasible. This enables the use of multigrid within shift-and-invert type eigensolvers. We show numerical results from our MPI-C implementation of a Rayleigh quotient iteration with multigrid. For state-of-the-art lat…

Visually Perceived Distance Judgments: Tablet-Based Augmented Reality Versus the Real World

2016

Does visually perceived distance differ when objects are viewed in augmented reality (AR), as opposed to the real world? What are the differences? These questions are theoretically interesting, and the answers are important for the development of many tablet- and phone-based AR applications, including mobile AR navigation systems. This article presents a thorough literature review of distance judgment experimental protocols, and results from several areas of perceptual psychology. In addition to distance judgments of real and virtual objects, this section also discusses previous work in measuring the geometry of virtual picture space and considers how this work might be relevant to tablet A…