Immersive Learning Research Network

Computer games have now been around for over three decades and the term serious games has been attributed to the use of computer games that are thought to have educational value. Game-based learning (GBL) has been applied in a number of different fields such as medicine, languages and software engineering. Furthermore, serious games can be a very effective as an instructional tool and can assist learning by providing an alternative way of presenting instructions and content on a supplementary level, and can promote student motivation and interest in subject matter resulting in enhanced learning effectiveness. REVLAW (Real and Virtual Reality Law) is a research project that the departments of Law and Computer Science of Westminster University have proposed as a new framework in which law students can explore a real case scenario using Virtual Reality (VR) technology to discover important pieces of evidence from a real-given scenario and make up their mind over the crime case if this is a murder or not. REVLAW integrates the immersion into VR as the perception of being physically present in a non-physical world. The paper presents the prototype framework and the mechanics used to make students focus on the crime case and make the best use of this immersive learning approach

A methodology for full-system power modeling in heterogeneous data centers

The need for energy-awareness in current data centers has encouraged the use of power modeling to estimate their power consumption. However, existing models present noticeable limitations, which make them application-dependent, platform-dependent, inaccurate, or computationally complex. In this paper, we propose a platform-and application-agnostic methodology for full-system power modeling in heterogeneous data centers that overcomes those limitations. It derives a single model per platform, which works with high accuracy for heterogeneous applications with different patterns of resource usage and energy consumption, by systematically selecting a minimum set of resource usage indicators and extracting complex relations among them that capture the impact on energy consumption of all the resources in the system. We demonstrate our methodology by generating power models for heterogeneous platforms with very different power consumption profiles. Our validation experiments with real Cloud applications show that such models provide high accuracy (around 5% of average estimation error).This work is supported by the Spanish Ministry of Economy and Competitiveness under contract TIN2015-65316-P, by the Gener- alitat de Catalunya under contract 2014-SGR-1051, and by the European Commission under FP7-SMARTCITIES-2013 contract 608679 (RenewIT) and FP7-ICT-2013-10 contracts 610874 (AS- CETiC) and 610456 (EuroServer).Peer ReviewedPostprint (author's final draft

Many-body effects on the capacitance of multilayers made from strongly correlated materials

Recent work by Kopp and Mannhart on novel electronic systems formed at oxide interfaces has shown interesting effects on the capacitances of these devices. We employ inhomogeneous dynamical mean-field theory to calculate the capacitance of multilayered nanostructures. These multilayered nanostructures are composed of semi-infinite metallic leads coupled via a strongly correlated dielectric barrier region. The barrier region can be adjusted from a metallic regime to a Mott insulator through adjusting the interaction strength. We examine the effects of varying the barrier width, temperature, potential difference, screening length, and chemical potential. We find that the interaction strength has a relatively strong effect on the capacitance, while the potential and temperature show weaker dependence.Comment: 19 pages, 7 figures, REVTe

Localized basis sets for unbound electrons in nanoelectronics

It is shown how unbound electron wave functions can be expanded in a suitably chosen localized basis sets for any desired range of energies. In particular, we focus on the use of gaussian basis sets, commonly used in first-principles codes. The possible usefulness of these basis sets in a first-principles description of field emission or scanning tunneling microscopy at large bias is illustrated by studying a simpler related phenomenon: The lifetime of an electron in a H atom subjected to a strong electric field.Comment: 6 pages, 5 figures, accepted by J. Chem. Phys. (http://jcp.aip.org/

Ultrafast optical rotations of electron spins in quantum dots

Coherent manipulation of quantum bits (qubits) on time scales much shorter than the coherence time is a key prerequisite for quantum information processing. Electron spins in quantum dots (QDs) are particularly attractive for implementations of qubits. Efficient optical methods for initialization and readout of spins have been developed in recent years. Spin coherence times in the microsecond range have been demonstrated, so that spin control by picosecond optical pulses would be highly desirable. Then a large number of spin rotations could be performed while coherence is maintained. A major remaining challenge is demonstration of such rotations with high fidelity. Here we use an ensemble of QD electron spins focused into a small number of precession modes about a magnetic field by periodic optical pumping. We demonstrate ultrafast optical rotations of spins about arbitrary axes on a picosecond time scale using laser pulses as control fields.Comment: 10 pages, 4 figure

Character of eigenstates of the 3D disordered Anderson Hamiltonian

We study numerically the character of electron eigenstates of the three dimensional disordered Anderson model. Analysis of the statistics of inverse participation ratio as well as numerical evaluation of the electron-hole correlation function confirm that there are no localized states below the mobility edge, as well as no metallic state in the tail of the conductive band. We discuss also finite size effects observed in the analysis of all the discussed quantities.Comment: 7 pages, 9 figures, resubmitted to Physical Review

Dynamical mean field theory for strongly correlated inhomogeneous multilayered nanostructures

Dynamical mean field theory is employed to calculate the properties of multilayered inhomogeneous devices composed of semi-infinite metallic lead layers coupled via barrier planes that are made from a strongly correlated material (and can be tuned through the metal-insulator Mott transition). We find that the Friedel oscillations in the metallic leads are immediately frozen in and don't change as the thickness of the barrier increases from one to eighty planes. We also identify a generalization of the Thouless energy that describes the crossover from tunneling to incoherent Ohmic transport in the insulating barrier. We qualitatively compare the results of these self-consistent many-body calculations with the assumptions of non-self-consistent Landauer-based approaches to shed light on when such approaches are likely to yield good results for the transport.Comment: 15 pages, 12 figures, submitted to Phys. Rev.