Dynamics of the entanglement between two oscillators in the same environment

We provide a complete characterization of the evolution of entanglement between two oscillators coupled to a common environment. For initial Gaussian states we identify three phases with different qualitative long time behavior: There is a phase where entanglement undergoes a sudden death (SD). Another phase (SDR) is characterized by an infinite sequence of events of sudden death and revival of entanglement. In the third phase (NSD) there is no sudden death of entanglement, which persist for long time. The phase diagram is described and analytic expressions for the boundary between phases are obtained. Numerical simulations show the accuracy of the analytic expressions. These results are applicable to a large variety of non--Markovian environments. The case of non--resonant oscillators is also numerically investigated.Comment: 4 pages, 5 figure

Entanglement dynamics during decoherence

The evolution of the entanglement between oscillators that interact with the same environment displays highly non-trivial behavior in the long time regime. When the oscillators only interact through the environment, three dynamical phases were identified and a simple phase diagram characterizing them was presented. Here we generalize those results to the cases where the oscillators are directly coupled and we show how a degree of mixidness can affect the final entanglement. In both cases, entanglement dynamics is fully characterized by three phases (SD: sudden death, NSD: no-sudden death and SDR: sudden death and revivals) which cover a phase diagram that is a simple variant of the previously introduced one. We present results when the oscillators are coupled to the environment through their position and also for the case where the coupling is symmetric in position and momentum (as obtained in the RWA). As a bonus, in the last case we present a very simple derivation of an exact master equation valid for arbitrary temperatures of the environment.Comment: to appear in QIP special issue on Quantum Decoherence and Entanglemen

Engineering context updates

Context has become a concept with practical applications in Computer Science. It is a complex concept which has been used often, however one which is not well understood, and its use is often superficial. This article highlights some considerations which may be important for our technical community to think more explicitly and to investigate in further depth. The contribution of this article is in highlighting the ramifications of system updates in the contexts being considered. The goal is to encourage future closer analysis and the development of much needed design and development tools that can provide support for developing systems which are more resilient to context updates

AAL4DS (Can AAL technology help people with Down’s Syndrome to live better lives?)

AAL has been extensively developed in the last few years, especially in relation to people with dementia and elderly people in general. However, there are segments of the population which are equally deserving of assistive technologies and yet have not attracted so much attention from our community. For example, there is very little research and focus on people with Down Syndrome, still they can benefit from AAL for similar reasons and yet they have their own specific needs and interaction capabilities which mean they may not necessarily benefit from current AAL systems without re-engineering. This paper discusses how AAL technology can be relevant to people with Down Syndrome at different stages of their lives

A smart campus template

We highlight a lack of models and theories associated with the Smart Campus concept and also an absence of processes to support its design and development. This paper provides a first approach to a theory and a set of design principles to guide their development. The theory and principles are flexible enough to be easily adapted and adopted by any organization interested in developing a Smart Campus

Reflections on ambient intelligence systems handling of user preferences and needs

We start by assuming the hypothesis that Intelligent Environments are essentially user-centred systems and that the effectiveness of such systems is proportional to their knowledge of the user’s preferences and needs and to their capacity to deliver services based on that knowledge. We then start with the complex task of examining the intricacies of dealing with preferences and needs in a more systematic and computational way with the hope these concepts will be given more relevance in the future within our community. The aim of this discussion is to encourage future research to produce an effective way for Ambient Intelligence systems to represent and reason with the preferences and needs of the users of such systems

Contexts and context-awareness revisited from an intelligent environments perspective

Context is a useful concept somehow unconsciously used by humans in daily life problem-solving. Recently several subareas of computer science have been increasingly trying to rely on this concept to design systems with practical use in certain predefined circumstances. The perception is that imbuing in the system certain context-awareness qualities can support intelligent decision-making in specific practical situations. Despite a significant number of implemented systems which aim at providing context-awareness there is a lack of commonly accepted and used methodologies and tools. At the root of this, is the lack of agreement on a set of good principles or standards which can act as a guide to the scientific community and the developers interested in this class of systems. There have been some extensive surveys on the use of context, still there is no theoretical corpus emerging which we can use to discuss the essential concepts making up the fabric of contexts and its use by system developers. Here we attempted such enterprise at a level which is more formal than popular surveys, in a way that is not implementation dependent and in a way that highlights key concepts of relevance to developers. We reassessed first the basic concepts identifying the need to more prominently consider system beneficiaries’ satisfaction. We then transfer explicitly these values to a more formal outline of the basic components and the operations which emerge as relevant. We identify and highlight the tasks of context activation, comparison, influence, construction, and interaction. We hint at how these may work in practice and explained these through examples. We show how the theory is flexible enough by generalizing it to multiusers so that optimization of global preferences and expectations is used to drive system development and system behaviour