Channel and active component abstractions for WSN programming - a language model with operating system support

To support the programming of Wireless Sensor Networks, a number of unconventional programming models have evolved, in particular the event-based model. These models are non-intuitive to programmers due to the introduction of unnecessary, non-intrinsic complexity. Component-based languages like Insense can eliminate much of this unnecessary complexity via the use of active components and synchronous channels. However, simply layering an Insense implementation over an existing event-based system, like TinyOS, while proving efficacy, is insufficiently space and time efficient for production use. The design and implementation of a new language-specific OS, InceOS, enables both space and time efficient programming of sensor networks using component-based languages like Insense

Spray: programming with a persistent distributed heap

We introduce a programming paradigm for distributed applications based on a persistent distributed heap. A proof-of-concept implementation is provided as a Javascript library, together with several examples that embody popular patterns for web applications

Harnessing content and context for enhanced decision making

In a time in which a significant amount of interpersonal interactions take place online, one must enquire to which extent are these milieus suitable for supporting the complexity of our communication. This is especially important in more sensitive domains, such as the one of Online Dispute Resolution, in which inefficient communication environments may result in misunderstandings, poor decisions or the escalation of the conflict. The conflict manager, in particular, may find his skills severely diminished, namely in what concerns the accurate perception of the state of the parties. In this paper the development of a rich communication framework is detailed that conveys contextual information about their users, harnessed from the transparent analysis of their behaviour while communicating. Using it, the conflict manager may not only better perceive the conflict and how it affects each party but also take better contextualized decisions, closer to the ones taken in face-to-face settings.This work is part-funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT { Fundação para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-028980 (PTDC/EEI-SII/1386/2012) and project PEst- OE/EEI/UI0752/2014

Imaging Light-Induced Migration of Dislocations in Halide Perovskites with 3D Nanoscale Strain Mapping

In recent years, halide perovskite materials have been used to make high performance solar cell and light-emitting devices. However, material defects still limit device performance and stability. Here, we use synchrotron-based Bragg Coherent Diffraction Imaging to visualise nanoscale strain fields, such as those local to defects, in halide perovskite microcrystals. We find significant strain heterogeneity within MAPbBr$_{3}$ (MA = CH$_{3}$NH$_{3}^{+}$) crystals in spite of their high optoelectronic quality, and identify both $\langle$100$\rangle$ and $\langle$110$\rangle$ edge dislocations through analysis of their local strain fields. By imaging these defects and strain fields in situ under continuous illumination, we uncover dramatic light-induced dislocation migration across hundreds of nanometres. Further, by selectively studying crystals that are damaged by the X-ray beam, we correlate large dislocation densities and increased nanoscale strains with material degradation and substantially altered optoelectronic properties assessed using photoluminescence microscopy measurements. Our results demonstrate the dynamic nature of extended defects and strain in halide perovskites and their direct impact on device performance and operational stability.Comment: Main text and Supplementary Information. Main text: 15 pages, 4 figures. Supplementary Information: 16 pages, 27 figures, 1 tabl

Linking Scottish vital event records using family groups

Funding: This work was supported by ESRC Grants ES/K00574X/2 “Digitising Scotland” and ES/L007487/1 “Administrative Data Research Centre – Scotland.”The reconstitution of populations through linkage of historical records is a powerful approach to generate longitudinal historical microdata resources of interest to researchers in various fields. Here we consider automated linking of the vital events recorded in the civil registers of birth, death and marriage compiled in Scotland, to bring together the various records associated with the demographic events in the life course of each individual in the population. From the histories, the genealogical structure of the population can then be built up. Rather than apply standard linkage techniques to link the individuals on the available certificates, we explore an alternative approach, inspired by the family reconstitution techniques adopted by historical demographers, in which the births of siblings are first linked to form family groups, after which intergenerational links between families can be established. We report a small-scale evaluation of this approach, using two district-level data sets from Scotland in the late nineteenth century, for which sibling links have already been created by demographers. We show that quality measures of up to 83% can be achieved on these data sets (using F-Measure, a combination of precision and recall). In the future, we intend to compare the results with a standard linkage approach and to investigate how these various methods may be used in a project which aims to link the entire Scottish population from 1856 to 1973.PostprintPeer reviewe

Self-adaptation applied to peer-set maintenance in Chord via a generic autonomic management framework

Self-adaptation can be achieved by autonomic management of facets of a system’s constituent components. This paper reports on a generic autonomic management frame-work and on its application to a key-based routing protocol as used in the peer-to-peer overlay Chord. The framework implements generic components of the autonomic management cycle. In the work reported here it was used to build a manager which autonomically controls the maintenance scheduling of the peer-set in individual Chord nodes, governed by some high-level policies. This manager improved routing performance and resource consumption in comparison to statically configured Chord nodes in a deployed network which was exposed to various membership churn and workload patterns.Postprin

Octopus: A Reflective Language Mechanism for Object Manipulation

A class of database programs exist which are required to operate over an infinite number of types; included in this class are object browsers and query tools. The types over which these programs operate cannot be enumerated statically. One solution to this problem is to provide a reflective language mechanism that permits the types of values to be abstracted over and the values manipulated in a type independent manner; this paper describes such a mechanism. The mechanism is called Octopus which is an acronym for Object Closure Transplantable to Other Persistent User Spaces. The essence of the technique is to allow values from the programming language value space to be hoisted up to a meta level and manipulated in ways which the programming language would not otherwise permit. When manipulation is complete they may be dropped back into the value space, provided that they still conform to the language’s type system. An additional feature of this technique, as the name suggests, is the ability to isolate portions of closures, and copy them to other locations. Partial closures may be rewired, possibly in a different context, using the meta level interface supplied by Octopus

Architectural support for Global Smart Spaces

This work was supported by EPSRC grant GR/M78403/GR/M76225, “Supporting Internet Computation in Arbitrary Geographical Locations”.A GLObal Smart Space (GLOSS) provides support for interaction amongst people, artefacts and places while taking account of both context and movement on a global scale. Crucial to the definition of a GLOSS is the provision of a set of location-aware services that detect, convey, store and exploit location information. We use one of these services, hearsay, to illustrate the implementation dimensions of a GLOSS. The focus of the paper is on both local and global software architecture to support the implementation of such services. The local architecture is based on XML,pipelines and is used to construct location-aware components. The global architecture is based on a hybrid peer-to-peer routing scheme and provides the local architectures with the means to communicate in the global context.Postprin