Ambient-aware continuous care through semantic context dissemination

Background: The ultimate ambient-intelligent care room contains numerous sensors and devices to monitor the patient, sense and adjust the environment and support the staff. This sensor-based approach results in a large amount of data, which can be processed by current and future applications, e. g., task management and alerting systems. Today, nurses are responsible for coordinating all these applications and supplied information, which reduces the added value and slows down the adoption rate. The aim of the presented research is the design of a pervasive and scalable framework that is able to optimize continuous care processes by intelligently reasoning on the large amount of heterogeneous care data. Methods: The developed Ontology-based Care Platform (OCarePlatform) consists of modular components that perform a specific reasoning task. Consequently, they can easily be replicated and distributed. Complex reasoning is achieved by combining the results of different components. To ensure that the components only receive information, which is of interest to them at that time, they are able to dynamically generate and register filter rules with a Semantic Communication Bus (SCB). This SCB semantically filters all the heterogeneous care data according to the registered rules by using a continuous care ontology. The SCB can be distributed and a cache can be employed to ensure scalability. Results: A prototype implementation is presented consisting of a new-generation nurse call system supported by a localization and a home automation component. The amount of data that is filtered and the performance of the SCB are evaluated by testing the prototype in a living lab. The delay introduced by processing the filter rules is negligible when 10 or fewer rules are registered. Conclusions: The OCarePlatform allows disseminating relevant care data for the different applications and additionally supports composing complex applications from a set of smaller independent components. This way, the platform significantly reduces the amount of information that needs to be processed by the nurses. The delay resulting from processing the filter rules is linear in the amount of rules. Distributed deployment of the SCB and using a cache allows further improvement of these performance results

An efficient MAC-based scheme against pollution attacks in XOR network coding-enabled WBANs for remote patient monitoring systems

Wireless Body Area Networks (WBANs) play a pivotal role to remote patient monitoring which is one of the main applications of m-Health. However, WBANs comprise a subset of Wireless Sensor Networks (WSNs), and thus, they inherit the limitations of WSNs in terms of communication bandwidth, reliability and power consumption that should be addressed so that WBANs can reach their full potential. Towards this direction, XOR Network Coding (NC) is a promising solution for WBANs. Nevertheless, XOR NC is vulnerable to pollution attacks, where adversaries (i.e., compromised intermediate nodes) inject into the network corrupted packets that prevent the destination nodes from decoding correctly. This has as a result not only network resource waste but also energy waste at the intermediate nodes. In this sense, pollution attacks comprise a serious threat against WBANs (i.e., resource-constrained wireless networks), that should be addressed so that WBANs can reap the benefits of XOR NC. Therefore, in this paper, we propose an efficient Message Authentication Code (MAC)-based scheme providing resistance against pollution attacks in XOR NC-enabled WBANs for remote patient monitoring systems. Our proposed scheme makes use of a number of MACs which are appended to the end of each native packet. Our results show that the proposed MAC-based scheme is more efficient compared to other competitive schemes for securing XOR NC against pollution attacks in resource-constrained wireless networks, in terms of communication bandwidth and computational complexity

Polyvinylidene fluoride dense membrane for the pervaporation of methyl acetate-methanol mixtures

In the context of pervaporative separation of methyl acetate-methanol binary mixtures, polyvinylidene fluoride (PVDF) pervaporation membranes were prepared in order to selectively separate methyl acetate by pervaporation.The PVDF membranes were compared to chlorinated polypropylene and polyvinyl alcohol dense membranes (developed for the same application) by pervaporation of a quaternary equimolar methyl acetate-methanol-. n-butyl acetate-. n-butanol reference feed. PVDF membranes resulted in a permeate richer in methyl acetate than the corresponding quaternary feed, and in a selectivity methyl acetate/methanol higher than one for the same mixture. Chlorinated polypropylene and polyvinyl alcohol membranes gave a permeate richer of both methanol and methyl acetate than the corresponding feed and were thus not applicable during the extensive study on the binary methyl acetate-methanol mixture.These preliminary results performances were also assessed with the Hansen solubility parameters theory, which resulted inadequate for predicting the behavior of the two glassy-state and the rubbery-state (PVDF) polymeric membranes during pervaporation.Thus, pervaporation of methyl acetate-methanol binary mixtures by PVDF membranes was studied experimentally using feed concentrations in the range 11-78mol% methyl acetate, and temperatures in the range 30-44°C, resulting in separation factors methyl acetate/methanol above 1 (up to 2.1 at 11mol% methyl acetate in the feed), in the whole feed concentration range. High total fluxes up to 35kgm-2h-1 (at 78mol% methyl acetate and 44°C) were also observed.Interestingly, when removing the contribution of the driving force to the separation, for concentrations below 60. mol% methyl acetate in the feed the membrane was selective for methanol, while for higher concentrations it was selective for methyl acetate (values up to 1.44).This work shows that methyl acetate selective membranes (starting from the improvement of PVDF membranes) are realistic and can be employed in order to concentrate low content methyl acetate-methanol industrial waste streams