Domestic thermal upgrades, community action and energy saving: a three-year experimental study of prosperous households

A three-year field experiment was conducted with 185 prosperous households to assess whether behavioural interventions by a community environmental group during and after thermal upgrades (cavity wall and/or loft insulation) can achieve reductions in households’ energy use, including reductions in direct and indirect rebound. The engineering interventions on the thermal efficiency of dwellings appear effective in reducing energy use in both treatment and control groups: a direct rebound effect is estimated to be at most 40 per cent from the engineering interventions. However, across a range of measures of energy use, we observe no significant effect of the community behavioural intervention across the total lifetime of the project. Qualitative data collected on similar community groups suggests substantial constraints on their capacity to realise reductions in energy use amongst households

Social technologies for online learning: theoretical and contextual issues

Three exemplars are presented of social technologies deployed in educational contexts: wikis; a photo-sharing environment; and a social bookmarking tool. Students were found to engage with the technologies selectively, sometimes rejecting them, in the light of their prior conceptions of education. Some students (a minority in all the studies) were unsympathetic to the educational philosophy underpinning the technology’s adoption. The paper demonstrates, through an examination of in-context use, the importance of socio-cultural factors in relation to education, and the non-deterministic nature of educational technology. The academic study of technology has increasingly called into question the deterministic views which are so pervasive in popular discourse and among policy makers. Instead, socio-cultural factors play a crucial role in shaping and defining technology and educational technology is no exception, as the examples in the paper show. The paper concludes by drawing out some implications of the examples for the use of social technologies in education

Formal Verification of a Rover Anti-collision System

In this paper, we integrate inductive proof, bounded model checking, test case generation and equivalence proof techniques to verify an embedded system. This approach is implemented using Systerel Smart Solver (S3) toolset. It is applied to verify properties at system, software, and code levels. The verification process is illustrated on an anti-collision system (ARP for Automatic Rover Protection) implemented on-board a rover. Focus is placed on the verification of safety and functional properties and the proof of equivalence between the design model and the generated code

Electro-luminescence and associated two carrier effects in cadmium sulphide

The properties of cad sulphide are such that the material has some potential for use in the semiconductor industry. The potential has so far not been realised because of the difficulty of preparing crystals with controlled properties. In order to improve the material available, much work has been carried out to identify and measure the parameters of the defects in the material. The study of double injection phenomena is one tool which enables defects to be investigated. During the work which forms the basis of this thesis, a large number of double injection devices have been fabricated from crystals grown by sublimation of CdS powder in a stream of argon. The devices have been studied at temperatures in the range 90 to 300 ºk and at temperatures below about 150 ºk visible green light is emitted when currents above about 5 mA flow. The light is due to recombination in the bulk and on the surface of the crystals, A comparison of the photo-, electro-, and cathodo- luminescent spectra has been made. The electrical measurements reveal that the current flow is governed by a class IT centre located 0.98 eV above the valence band. The presence of this centre leads to a switching effect which is such that the device can be turned on when a voltage pulse or a pulse of light is applied to the device when biased below threshold. When pulsed voltages are applied, the current pulse has a step in it due to a fraction of the class II centres capturing electrons while the pulse is off. The maximum frequency of sine wave modulation of the light has been found to be less than 1 megacycle so that the CdS device is unlikely to compete with injection lasers in other materials as a source of light for optical telecommunication systems

A hazard analysis method for systematic identification of safety requirements for user interface software in medical devices

© Springer International Publishing AG (outside the US) 2017. Formal methods technologies have the potential to verify the usability and safety of user interface (UI) software design in medical devices, enabling significant reductions in use errors and consequential safety incidents with such devices. This however depends on comprehensive and verifiable safety requirements to leverage these techniques for detecting and preventing flaws in UI software that can induce use errors. This paper presents a hazard analysis method that extends Leveson’s System Theoretic Process Analysis (STPA) with a comprehensive set of causal factor categories, so as to provide developers with clear guidelines for systematic identification of use-related hazards associated with medical devices, their causes embedded in UI software design, and safety requirements for mitigating such hazards. The method is evaluated with a case study on the Gantry-2 radiation therapy system, which demonstrates that (1) as compared to standard STPA, our method allowed us to identify more UI software design issues likely to cause use-related hazards; and (2) the identified UI software design issues facilitated the definition of precise, verifiable safety requirements for UI software, which could be readily formalized in verification tools such as Prototype Verification System (PVS).- U.S. Food and Drug Administration(NORTE-01-0145-FEDER-000016)Sandy Weininger (FDA), Scott Thiel (Navigant Consulting, Inc.), Michelle Jump (Stryker), Stefania Gnesi (ISTI/CNR) and the CHI+MED team (www.chi-med.ac.uk) provided useful feedback and inputs. Paolo Masci’s work is supported by the North Portugal Regional Operational Programme (NORTE 2020) under the PORTUGAL 2020 Partnership Agreement, and by the European Regional Development Fund (ERDF) within Project “NORTE-01-0145-FEDER-000016”.info:eu-repo/semantics/publishedVersio

Analysis and Optimization of Distributed Real-Time Embedded Systems

An increasing number of real-time applications are today implemented using distributed heterogeneous architectures composed of interconnected networks of processors. The systems are heterogeneous not only in terms of hardware and software components, but also in terms of communication protocols and scheduling policies. In this context, the task of designing such systems is becoming increasingly difficult. The success of new adequate design methods depends on the availability of efficient analysis as well as optimization techniques. In this article, we present both analysis and optimization approaches for such heterogeneous distributed real-time embedded systems. More specifically, we discuss the schedulability analysis of hard real-time systems, highlighting particular aspects related to the heterogeneous and distributed nature of the applications. We also introduce several design optimization problems characteristic of this class of systems: mapping of functionality, the optimization of access to communication channel, and the assignment of scheduling policies to processes. Optimization heuristics aiming at producing a schedulable system with a given amount of resources are presented. © 2006 ACM.</p

PACE-UP (Pedometer and consultation evaluation--UP)--a pedometer-based walking intervention with and without practice nurse support in primary care patients aged 45-75 years: study protocol for a randomised controlled trial.

BACKGROUND: Most adults do not achieve the 150 minutes weekly of at least moderate intensity activity recommended for health. Adults' most common physical activity (PA) is walking, light intensity if strolling, moderate if brisker. Pedometers can increase walking; however, most trials have been short-term, have combined pedometer and support effects, and have not reported PA intensity. This trial will investigate whether pedometers, with or without nurse support, can help less active 45-75 year olds to increase their PA over 12 months. METHODS/DESIGN: DESIGN: Primary care-based 3-arm randomized controlled trial with 12-month follow-up and health economic and qualitative evaluations. PARTICIPANTS: Less active 45-75 year olds (n = 993) will be recruited by post from six South West London general practices, maximum of two per household and households randomised into three groups. Step-count and time spent at different PA intensities will be assessed for 7 days at baseline, 3 and 12 months by accelerometer. Questionnaires and anthropometric assessments will be completed. INTERVENTION: The pedometer-alone group will be posted a pedometer (Yamax Digi-Walker SW-200), handbook and diary detailing a 12-week pedometer-based walking programme, using targets from their baseline assessment. The pedometer-plus-support group will additionally receive three practice nurse PA consultations. The handbook, diary and consultations include behaviour change techniques (e.g., self-monitoring, goal-setting, relapse prevention planning). The control group will receive usual care. OUTCOMES: Changes in average daily step-count (primary outcome), time spent sedentary and in at least moderate intensity PA weekly at 12 months, measured by accelerometry. Other outcomes include change in body mass index, body fat, self-reported PA, quality of life, mood and adverse events. Cost-effectiveness will be assessed by the incremental cost of the intervention to the National Health Service and incremental cost per change in step-count and per quality adjusted life year. Qualitative evaluations will explore reasons for trial non-participation and the interventions' acceptability. DISCUSSION: The PACE-UP trial will determine the effectiveness and cost-effectiveness of a pedometer-based walking intervention delivered by post or practice nurse to less active primary care patients aged 45-75 years old. Approaches to minimise bias and challenges anticipated in delivery will be discussed

Little evidence for a reduced late positive potential to unpleasant stimuli in major depressive disorder

Background: Individuals with major depressive disorder (MDD) present with deficits in emotional reactivity. Conflicting models have been proposed to explain this effect. We sought to confirm reports of blunted reactivity to negatively-valanced emotional stimuli, in line with the emotional context insensitivity hypothesis of depression, in a preregistered study. Methods: Forty-one depressed participants and 41 age- and gender-matched healthy controls were presented a series of unpleasant and neutrally-valanced pictures in a passive view paradigm while acquiring electroencephalography (EEG). The late positive potential (LPP), an EEG correlate of emotional reactivity, was compared between groups using mixed-effects repeated-measures models and exploratory cluster-based permutation tests. A sensitivity analysis was performed to assess the robustness of LPP findings by reanalysing the LPPs using 24 EEG pipelines from studies identified in the literature. Results: We found no difference in LPP amplitudes between MDD and healthy individuals using the preregistered analysis pipeline. The sensitivity analysis revealed that the magnitude and direction of LPP effect sizes were affected by the analysis pipeline. Exploratory permutation analysis revealed an electrode cluster that showed a significant reduction in the LPP for MDD participants while viewing unpleasant pictures. Conclusions: These results do not provide evidence in support of the emotional context insensitivity hypothesis, except for the exploratory data-driven approach. Methodological differences, in particular in the analysis pipeline, contribute to the heterogeneity of LPP modulation in depression. A standardised approach to quantify EEG correlates of emotional reactivity is needed to evaluate alternative models of emotional reactivity in depression

The cost of changing physical activity behaviour: Evidence from a "physical activity pathway" in the primary care setting

Copyright @ 2011 Boehler et al.BACKGROUND: The ‘Physical Activity Care Pathway’ (a Pilot for the ‘Let’s Get Moving’ policy) is a systematic approach to integrating physical activity promotion into the primary care setting. It combines several methods reported to support behavioural change, including brief interventions, motivational interviewing, goal setting, providing written resources, and follow-up support. This paper compares costs falling on the UK National Health Service (NHS) of implementing the care pathway using two different recruitment strategies and provides initial insights into the cost of changing physical activity behaviour. METHODS: A combination of a time driven variant of activity based costing, audit data through EMIS and a survey of practice managers provided patient-level cost data for 411 screened individuals. Self reported physical activity data of 70 people completing the care pathway at three month was compared with baseline using a regression based ‘difference in differences’ approach. Deterministic and probabilistic sensitivity analyses in combination with hypothesis testing were used to judge how robust findings are to key assumptions and to assess the uncertainty around estimates of the cost of changing physical activity behaviour. RESULTS: It cost £53 (SD 7.8) per patient completing the PACP in opportunistic centres and £191 (SD 39) at disease register sites. The completer rate was higher in disease register centres (27.3% vs. 16.2%) and the difference in differences in time spent on physical activity was 81.32 (SE 17.16) minutes/week in patients completing the PACP; so that the incremental cost of converting one sedentary adult to an ‘active state’ of 150 minutes of moderate intensity physical activity per week amounts to £ 886.50 in disease register practices, compared to opportunistic screening. CONCLUSIONS: Disease register screening is more costly than opportunistic patient recruitment. However, additional costs come with a higher completion rate and better outcomes in terms of behavioural change in patients completing the care pathway. Further research is needed to rigorously evaluate intervention efficiency and to assess the link between behavioural change and changes in quality adjusted life years (QALYs).This article is available through the Brunel Open Access Publishing Fund

Comprehending Isabelle/HOL's consistency

The proof assistant Isabelle/HOL is based on an extension of Higher-Order Logic (HOL) with ad hoc overloading of constants. It turns out that the interaction between the standard HOL type definitions and the Isabelle-specific ad hoc overloading is problematic for the logical consistency. In previous work, we have argued that standard HOL semantics is no longer appropriate for capturing this interaction, and have proved consistency using a nonstandard semantics. The use of an exotic semantics makes that proof hard to digest by the community. In this paper, we prove consistency by proof-theoretic means—following the healthy intuition of definitions as abbreviations, realized in HOLC, a logic that augments HOL with comprehension types. We hope that our new proof settles the Isabelle/HOL consistency problem once and for all. In addition, HOLC offers a framework for justifying the consistency of new deduction schemas that address practical user needs