Inflationary scenario from higher curvature warped spacetime

We consider a five dimensional AdS spacetime, in presence of higher curvature term like $F(R) = R + \alpha R^2$ in the bulk, in the context of Randall-Sundrum two-brane model. Our universe is identified with the TeV scale brane and emerges as a four dimensional effective theory. From the perspective of this effective theory, we examine the possibility of "inflationary scenario" by considering the on-brane metric ansatz as an FRW one. Our results reveal that the higher curvature term in the five dimensional bulk spacetime generates a potential term for the radion field. Due to the presence of radion potential, the very early universe undergoes a stage of accelerated expansion and moreover the accelerating period of the universe terminates in a finite time. We also find the spectral index of curvature perturbation ($n_s$) and tensor to scalar ratio ($r$) in the present context, which match with the observational results based on the observations of $Planck$ $2015$.Comment: 10 pages, 5 figures. arXiv admin note: text overlap with arXiv:1701.0157

Analysing mobile learning designs: A framework for transforming learning post-COVID

Mobile learning is well established in literature and practice, but under-evolved from a rigorous learning design perspective. Activity theory presents a sophisticated way of mapping and understanding learning design, but for mobile learning this does not always translate into change in practice. The reported research addresses this by coupling a mobile learning specific approach to activity theory with a practice-based framework: the design for transformative mobile learning framework mapped to the pedagogy-andragogy-heutagogy continuum matrix (the DTML-PAH Matrix). Seven case studies are analysed using this approach and presented narratively along with framework informed analysis. Findings include that the DTML-PAH Matrix can be used to provide clearer implications and guidance for mobile learning practice, and that the DTML-PAH Matrix can also be guided by the practice over time. Implications for further research and practice are discussed. Implications for practice or policy: Provide technological and pedagogical scaffolds to students. Learning designs should focus upon enabling elements of learner agency and creativity. To develop learning solutions to real world problems utilise a design-based research approach. Create authentic collaborative learning activities and tasks. Integrate mobile learning affordances in the design of the course and curriculum

Model checking time-constrained scenario-based specifications

We consider the problem of model checking message-passing systems with real-time requirements. As behavioural specifications, we use message sequence charts (MSCs) annotated with timing constraints. Our system model is a network of communicating finite state machines with local clocks, whose global behaviour can be regarded as a timed automaton. Our goal is to verify that all timed behaviours exhibited by the system conform to the timing constraints imposed by the specification. In general, this corresponds to checking inclusion for timed languages, which is an undecidable problem even for timed regular languages. However, we show that we can translate regular collections of time-constrained MSCs into a special class of event-clock automata that can be determinized and complemented, thus permitting an algorithmic solution to the model checking problem