Griffith University

About: Griffith University is a education organization based out in Brisbane, Queensland, Australia. It is known for research contribution in the topics: Population & Context (language use). The organization has 13830 authors who have published 49318 publications receiving 1420865 citations.

Density functional theory of time-dependent phenomena

Abstract: A density-functional formalism comparable to the theory of Hohenberg, Kohn and Sham is developed for electronic systems subject to time-dependent external fields. The formalism leads to a set of time-dependent Kohn-Sham equations which, in addition to the external potential, contain a time-dependent Hartree term and a local time-dependent exchange-correlation potential. Rigorous properties and explicit approximations of the latter are discussed in detail. Generalizations of the basic formalism to incorporate the nuclear motion and to deal with magnetic effects are described. Within the regime of linear-response theory, the time-dependent Kohn-Sham equations lead to a formally exact representation of the frequency-dependent linear density response. Applications within the linear-response regime include the computation of photoabsorbtion cross sections, the determination of van der Waals forces and the calculation of excitation energies. The latter is based on the fact that the frequency-dependent linear density response has poles at the true excitation energies of the interacting many-body system. The time-dependent Kohn-Sham formalism then leads to a simple additive correction of the Kohn-Sham single-particle excitation energies. Beyond the linear-response regime, the time-dependent Kohn-Sham scheme is applied to atoms in strong femto-second laser pulses to describe multi-photon ionization and harmonic generation in a non-perturbative way.

Survey on Recent Advances in Networked Control Systems

Abstract: Networked control systems (NCSs) are systems whose control loops are closed through communication networks such that both control signals and feedback signals can be exchanged among system components (sensors, controllers, actuators, and so on). NCSs have a broad range of applications in areas such as industrial control and signal processing. This survey provides an overview on the theoretical development of NCSs. In-depth analysis and discussion is made on sampled-data control, networked control, and event-triggered control. More specifically, existing research methods on NCSs are summarized. Furthermore, as an active research topic, network-based filtering is reviewed briefly. Finally, some challenging problems are presented to direct the future research.

Behavioral Outcomes of Parent-Child Interaction Therapy and Triple P—Positive Parenting Program: A Review and Meta-Analysis

Abstract: We conducted a review and meta-analyses of 24 studies to evaluate and compare the outcomes of two widely disseminated parenting interventions-Parent-Child Interaction Therapy and Triple P-Positive Parenting Program. Participants in all studies were caregivers and 3- to 12-year-old children. In general, our analyses revealed positive effects of both interventions, but effects varied depending on intervention length, components, and source of outcome data. Both interventions reduced parent-reported child behavior and parenting problems. The effect sizes for PCIT were large when outcomes of child and parent behaviors were assessed with parent-report, with the exclusion of Abbreviated PCIT, which had moderate effect sizes. All forms of Triple P had moderate to large effects when outcomes were parent-reported child behaviors and parenting, with the exception of Media Triple P, which had small effects. PCIT and an enhanced version of Triple P were associated with improvements in observed child behaviors. These findings provide information about the relative efficacy of two programs that have received substantial funding in the USA and Australia, and findings should assist in making decisions about allocations of funding and dissemination of these parenting interventions in the future.

Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer

Abstract: A consequence of the quantum mechanical uncertainty principle is that one may not discuss the path or "trajectory" that a quantum particle takes, because any measurement of position irrevocably disturbs the momentum, and vice versa. Using weak measurements, however, it is possible to operationally define a set of trajectories for an ensemble of quantum particles. We sent single photons emitted by a quantum dot through a double-slit interferometer and reconstructed these trajectories by performing a weak measurement of the photon momentum, postselected according to the result of a strong measurement of photon position in a series of planes. The results provide an observationally grounded description of the propagation of subensembles of quantum particles in a two-slit interferometer.