Handling large knowledge bases of information from different domains such as the World Wide Web is a complex problem addressed in the Resource Description Framework (RDF) by adding semantic meaning to the data itself. The amount of linked data has brought with it a number of specialized databases that are capable of storing and processing RDF data, called RDF stores. We explore the RDF store landscape with the aim of finding an RDF store that sufficiently meets the storage needs of an enhanced living environment, more concretely the requirements of a Smart Space platform aimed at running on a cluster set up of low-power hardware that can be run locally entirely at home with the purpose of logging data for a reactive assistive system involving, e.g., activity recognition or domotics. We present a literature analysis of RDF stores and identify promising candidates for implementation of consumer Smart Spaces. Based on the insights provided with our study, we conclude by suggesting different relevant aspects of RDF storage systems that need to be considered in Ambient Assisted Living environments and a comparison of available solutions.

Application Layer Forward Error Correction (AL-FEC) is becoming a popular addition to protocols for real-time video delivery over IP-based wireless networks. In particular, rateless codes are identified as suitable solution for AL-FEC due to their flexibility and capacity-approaching performance. Since each part of video data is not equally important for video reconstruction, it is beneficial to group it based on its importance, and then provide different degree of protection using Unequal Error Protection (UEP). Data partitioning (DP) is one such low-cost feature in H.264/AVC enabling partitioning of video data based on its importance. We propose schemes for the DP H.264/AVC video transmission using Raptor and Random Linear Codes (RLC) and investigate their performance as AL-FEC solutions in Digital Video Broadcasting. We provide comparisons between optimized Non-Overlapping Window RLC and Expanding Window (EW) RLC, which are two effective UEP RLC strategies. The results using realistic channel traces show viability of the EW RLC as a promising solution for multimedia broadcast applications.

The second generation terrestrial TV broadcasting standard from the digital video broadcasting (DVB) project, DVB-T2, has recently been standardized. In this article we perform a complexity analysis of our software defined implementation of the modulator/demodulator parts of a DVB-T2 transmitter and receiver. First we describe the various stages of a DVB-T2 modulator and demodulator, as well as how they have been implemented in our system. We then perform an analysis of the computational complexity of each signal processing block. The complexity analysis is performed in order to identify the blocks that are not feasible to run in realtime on a general purpose processor. Furthermore, we discuss implementing these computationally heavy blocks on other architectures, such as GPUs (graphics processing units) and FPGAs (field-programmable gate arrays), that would still allow them to be implemented in software and thus be easily reconfigurable.

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