Manipulating and protecting entanglement by means of spin environments

We study the dynamical behavior of two initially entangled qubits, each locally coupled to an environment embodied by an interacting spin chain. We consider energy-exchange qubit-environment couplings resulting in rich and highly non-trivial entanglement dynamics. We obtain exact results for the time evolution of the concurrence between the two qubits and find that, by tuning the interaction parameters, one can freeze the dynamics of entanglement, therefore inhibiting their relaxation into the spin environments, as well as activate a sudden-death phenomenon. We also discuss the effects of an environmental quantum phase transition on the features of the two-qubit entanglement dynamics.

A framework for collaborative working environments

To utilize the advantages of existing and emerging Internet techniques and to meet the demands for a new generation of collaborative working environments, a framework with an upperware–middleware architecture is proposed, which consists of four layers: resource layer, middleware layer, upperware layer and application layer. The upperware contains intelligent agents and plug/play facilities; the former coordinates and controls multiple middleware techniques such as Grid computing, Web-services and mobile agents, while the latter are used for the applications, such as semantic CAD, to plug and loose couple into the system. The method of migrating legacy software using automatic wrapper generation technique is also presented. A prototype mobile environment for collaborative product design is presented to illustrate the utilization of the CWE framework in collaborative design and manufacture.

Detection of aberrant behaviour in home environments from video sequence

We introduce an application for the detection of aberrant behaviour within home based environments, with a focus on repetitive actions, which may be present in instance of persons suffering from dementia. Video based analysis has been used to detect the motion of a person within a given scene in addition to tracking them over the time. Detection of repetitive actions has been based on the analysis of a person's trajectory using the principles of signal correlation. Along with the ability to detect repetitive motion the developed approach also has the ability to measure the amount of activity/inactivity within the scene during a given period of time. Our results showed that the developed approach had the ability to detect all patterns in the data set examined with an average accuracy of 96.67%. This work has therefore validated the proposed concept of video based analysis for the detection of repetitive activities.

Extent and variation of phage-borne bacterial 16S rRNA gene sequences in wastewater environments

Phage metagenomes isolated from wastewater over a 12-month period were analyzed. The results suggested that various strains of Proteobacteria, Bacteroidetes, and other phyla are likely to participate in transduction. The patterns of 16S rRNA sequences found in phage metagenomes did not follow changes in the total bacterial community.