Usability evaluation of a virtual museum interface

The Augmented Representation of Cultural Objects (ARCO) system provides software and interface tools to museum curators to develop virtual museum exhibitions, as well as a virtual environment for museum visitors over the World Wide Web or in informative kiosks. The main purpose of the system is to offer an enhanced educative and entertaining experience to virtual museum visitors. In order to assess the usability of the system, two approaches have been employed: a questionnaire based survey and a Cognitive Walkthrough session. Both approaches employed expert evaluators, such as domain experts and usability experts. The result of this study shows a fair performance of the followed approach, as regards the consumed time, financial and other resources, as a great deal of usability problems has been uncovered and many aspects of the system have been investigated. The knowledge gathered aims at creating a conceptual framework for diagnose usability problems in systems in the area of Virtual Cultural Heritage

Bone marrow mononuclear cells and acute myocardial infarction

PMCID: PMC3340546This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Research and Development Expenditures of Innovative Enterprises in the Time of Crisis

In an analysed group of enterprises the smallest "resistance" to crisis was observed in American companies. The enterprises from the EU also reduced research and development expenditures but the pace of a fall in these expenditures was smaller than in the case of American companies.W badanej zbiorowości przedsiębiorstw najmniejszą "odporność" na kryzys wykazaly firmy amerykańskie. Firmy wywodzące się z UE również zanotowaly zmniejszenie nakladów na badania i rozwój, jednak tempo spadku nakladów badawczo-rozwojowych bylo tu mniejsze niż w przypadku firm amerykańskich

Quantum fields, dark matter and non-standard Wigner classes

The Elko field of Ahluwalia and Grumiller is a quantum field for massive spin-1/2 particles. It has been suggested as a candidate for dark matter. We discuss our attempts to interpret the Elko field as a quantum field in the sense of Weinberg. Our work suggests that one should investigate quantum fields based on representations of the full Poincar\'e group which belong to one of the non-standard Wigner classes.Comment: 6 pages. Submitted to proceedings of Dark2009, Christchurch, New Zealand, January 200

Nonlinear stability of flock solutions in second-order swarming models

In this paper we consider interacting particle systems which are frequently used to model collective behavior in animal swarms and other applications. We study the stability of orientationally aligned formations called flock solutions, one of the typical patterns emerging from such dynamics. We provide an analysis showing that the nonlinear stability of flocks in second-order models entirely depends on the linear stability of the first-order aggregation equation. Flocks are shown to be nonlinearly stable as a family of states under reasonable assumptions on the interaction potential. Furthermore, we numerically verify that commonly used potentials satisfy these hypotheses and investigate the nonlinear stability of flocks by an extensive case-study of uniform perturbations.Comment: 22 pages, 1 figure, 1 tabl

Onboard image correction

A processor architecture for performing onboard geometric and radiometric correction of LANDSAT imagery is described. The design uses a general purpose processor to calculate the distortion values at selected points in the image and a special purpose processor to resample (calculate distortion at each image point and interpolate the intensity) the sensor output data. A distinct special purpose processor is used for each spectral band. Because of the sensor's high output data rate, 80 M bit per second, the special purpose processors use a pipeline architecture. Sizing has been done on both the general and special purpose hardware

On the Effective Equation of State of Dark Energy

In an effective field theory model with an ultraviolet momentum cutoff, there is a relation between the effective equation of state of dark energy and the ultraviolet cutoff scale. It implies that a measure of the equation of state of dark energy different from minus one, does not rule out vacuum energy as dark energy. It also indicates an interesting possibility that precise measurements of the infrared properties of dark energy can be used to probe the ultraviolet cutoff scale of effective quantum field theory coupled to gravity. In a toy model with a vacuum energy dominated universe with a Planck scale cutoff, the dark energy effective equation of state is -0.96.Comment: 7 pages, awarded honorable mention in the 2010 Gravity Research Foundation essay competitio