Home alone: autonomous extension and correction of spatial representations

In this paper we present an account of the problems faced by a mobile robot given an incomplete tour of an unknown environment, and introduce a collection of techniques which can generate successful behaviour even in the presence of such problems. Underlying our approach is the principle that an autonomous system must be motivated to act to gather new knowledge, and to validate and correct existing knowledge. This principle is embodied in Dora, a mobile robot which features the aforementioned techniques: shared representations, non-monotonic reasoning, and goal generation and management. To demonstrate how well this collection of techniques work in real-world situations we present a comprehensive analysis of the Dora system’s performance over multiple tours in an indoor environment. In this analysis Dora successfully completed 18 of 21 attempted runs, with all but 3 of these successes requiring one or more of the integrated techniques to recover from problems

An efficient method to reproduce the effects of acoustic forcing on gas turbine fuel injectors in incompressible simulations

Previous studies have highlighted the importance of both air mass flow rate and swirl fluctuations on the unsteady heat release of a swirl stabilised gas turbine combustor. The ability of a simulation to correctly resolve the heat release fluctuations or the flame transfer function (FTF), important for thermoacoustic analysis, is therefore dependent on the ability of the method to correctly include both the swirl number and mass flow rate fluctuations which emerge from the multiple air passages of a typical lean-burn fuel injector. The fuel injector used in this study is industry representative and has a much more complicated geometry than typical premixed, lab-scale burners and the interaction between each flow passage must be captured correctly. This paper compares compressible, acoustically forced, CFD (computational fluid dynamics) simulations with incompressible, mass flow rate forced simulations. Incompressible mass flow rate forcing of the injector, which is an attractive method due to larger timesteps, reduced computational cost and flexibility of choice of combustion model, is shown to be incapable of reproducing the swirl and mass flow fluctuations of the air passages given by the compressible simulation as well as the downstream flow development. This would have significant consequences for any FTF calculated by this method. However, accurate incompressible simulations are shown to be possible through use of a truncated domain with appropriate boundary conditions using data extracted from a donor compressible simulation. A new model is introduced based on the Proper Orthogonal Decomposition and Fourier Series (PODFS) that alleviates several weaknesses of the strong recycling method. The simulation using this method is seen to be significantly computationally cheaper than the compressible simulations. This suggests a methodology where a non-reacting compressible simulation is used to generate PODFS based boundary conditions which can be used in cheaper incompressible reacting FTF calculations. In an industrial context, this improved computational efficiency allows for greater exploration of the design space and improved combustor design

Strategies for Testing the Impact of Natural Flood Risk Management Measures

Natural Flood Management (NFM) is an approach that seeks to work with natural processes to enhance the flood regulating capacity of a catchment, whilst delivering a wide range of ecosystem services, from pollution assimilation to habitat creation and carbon storage. This chapter describes a tiered approach to NFM, commencing with strategic modelling to identify a range of NFM opportunities (tree-planting, distributed runoff attenuation features, and soil structure improvements), and their potential benefits, before engagement with catchment partners, and prioritisation of areas for more detailed hydrological modelling and uncertainty analysis. NFM measures pose some fundamental challenges in modelling their contribution to flood risk management because they are often highly distributed, can influence multiple catchment processes, and evidence for their effectiveness at the large scale is uncertain. This demands we model the ‘upstream’ in more detail so that we can assess the effectiveness of many small-scale changes at the large-scale. We demonstrate an approach to address these challenges employing the fast, high resolution, fully-distributed inundation model JFLOW, and visualisation of potential benefits in map form. These are used to engage catchment managers who can prioritise areas for potential deployment of NFM measures, where more detailed modelling may be targeted. We then demonstrate a framework applying the semi-distributed Dynamic TOPMODEL in which uncertainty plays an integral role in the decision-making process

The Pipeline of Enrichment: Supporting Link Creation for Continuous Media

The application of open hypermedia to temporal media has previously been explored with respect to the link service, in particular link delivery and generic linking. This paper is based on the notion of continuous metadata, in which we use metadata in a temporally significant manner to capture and convey the information required to support linking. With a focus on link creation and live processing, our approach enriches hypermedia content with additional metadata at a number of points between capture and delivery. We illustrate this approach with a tool which assists metadata capture by annotation of continuous media according to a simple ontology

Categorising the sub-mJy population: Star-forming galaxies from deep radio surveys

Models predict that starforming galaxies make up the majority of the source population detected in the very deepest radio surveys. Radio selected samples of starforming galaxies are therefore a potentially excellent method to chart e.g. the cosmic history of star-formation. However, a significant minority of the faintest radio sources are AGN powered ‘contaminants’, and must be removed from any solely star-formation powered sample. Here we describe a multi-pronged method for spearating star-forming and AGN powered sources in a deep 1.4 GHz radio survey. We utilise a wealth of multi-wavelength information, including radio spectral and morphological information and radio to mid-IR SED modelling, to select a clean sample of star-formation powered sources. We then derive the 1.4 GHz source counts separately for AGN and SFGs, calculate an independent measure of the evolving star-formation rate density to z∼2, and compare our results to the star-formation rate density determined at other wavelengths

Herschel/PACS observations of the host galaxy of GRB 031203

We present Herschel/PACS observations of the nearby (z = 0.1055) dwarf galaxy that has hosted the long gamma-ray burst (LGRB) 031203. Using the PACS data, we have been able to place constraints on the dust temperature, dust mass, total infrared (IR) luminosity and IR-derived star formation rate (SFR) for this object. We find that the GRB host galaxy (GRBH) 031203 has a total IR luminosity of 3 × 1010 L⊙ placing it in the regime of the IR-luminous galaxy population. Its dust temperature and specific SFR are comparable to that of many high-redshift (z = 0.3–2.5) IR-detected GRB hosts (Tdust > 40 K; sSFR > 10 Gyr−1); however, its dust-to-stellar mass ratio is lower than what is commonly seen in IR-luminous galaxies. Our results suggest that GRBH 031203 is undergoing a strong starburst episode and its dust properties are different to those of local dwarf galaxies within the same metallicity and stellar mass range. Furthermore, our measurements place it in a distinct class to the well-studied nearby host of GRB 980425 (z = 0.0085), confirming the notion that GRB host galaxies can span a large range in properties even at similar cosmological epochs, making LGRBs an ideal tool in selecting samples of star-forming galaxies up to high redshift

Blue carbon audit of Orkney waters

This study provides an audit of the potential blue carbon resources present in the coastal waters around Orkney, bounded by the 12 nautical mile limit and including the Loch of Stenness brackish water lagoon. This report builds on previous work in which blue carbon stocks in Marine Protected Areas in Scottish waters were estimated from i) contributions of biological material to the fixation of carbon, also referred to as production, and ii) contributions of sediments to blue carbon storage. The methodology has been further developed here to allow regional-scale estimation of habitat extent and provides estimates of blue carbon associated with habitats and surface sediments.Publisher PD

Descriptive epidemiology of energy expenditure in the UK: findings from the National Diet and Nutrition Survey 2008-15.

BACKGROUND: Little is known about population levels of energy expenditure, as national surveillance systems typically employ only crude measures. The National Diet and Nutrition Survey (NDNS) in the UK measured energy expenditure in a 10% subsample by gold-standard doubly labelled water (DLW). METHODS: DLW-subsample participants from the NDNS (383 males, 387 females) aged 4-91 years were recruited between 2008 and 2015 (rolling programme). Height and weight were measured and body-fat percentage estimated by deuterium dilution. RESULTS: Absolute total energy expenditure (TEE) increased steadily throughout childhood, ranging from 6.2 and 7.2 MJ/day in 4- to 7-year-olds to 9.7 and 11.7 MJ/day for 14- to 16-year-old girls and boys, respectively. TEE peaked in 17- to 27-year-old women (10.7 MJ/day) and 28- to 43-year-old men (14.4 MJ/day), before decreasing gradually in old age. Physical-activity energy expenditure (PAEE) declined steadily with age from childhood (87 kJ/day/kg in 4- to 7-year-olds) through to old age (38 kJ/day/kg in 71- to 91-year-olds). No differences were observed by time, region and macronutrient composition. Body-fat percentage was strongly inversely associated with PAEE throughout life, irrespective of expressing PAEE relative to body mass or fat-free mass. Compared with females with 40% recorded 29 kJ/day/kg body mass and 18 kJ/day/kg fat-free mass less PAEE in analyses adjusted for age, geographical region and time of assessment. Similarly, compared with males with 35% recorded 26 kJ/day/kg body mass and 10 kJ/day/kg fat-free mass less PAEE. CONCLUSIONS: This first nationally representative study reports levels of human-energy expenditure as measured by gold-standard methodology; values may serve as a reference for other population studies. Age, sex and body composition are the main determinants of energy expenditure. Key Messages This is the first nationally representative study of human energy expenditure, covering the UK in the period 2008-2015. Total energy expenditure (MJ/day) increases steadily with age throughout childhood and adolescence, peaks in the 3rd decade of life in women and 4th decade of life in men, before decreasing gradually in old age. Physical activity energy expenditure (kJ/day/kg or kJ/day/kg fat-free mass) declines steadily with age from childhood to old age, more steeply so in males. Body-fat percentage is strongly inversely associated with physical activity energy expenditure. We found little evidence that energy expenditure varied by geographical region, over time, or by dietary macronutrient composition.The authors were supported by the UK Medical Research Council (unit programme numbers. MC_UU_12015/1, MC_UU_12015/3, U105960371) and the NIHR Biomedical Research Centre in Cambridge (IS-BRC-1215-20014). TL was funded by the Cambridge Trust

The diversity of residential electricity demand – a comparative analysis of metered and simulated data

A comparative study between simulated residential electricity demand data and metered data from theUK Household Electricity Survey is presented. For this study, a high-resolution probabilistic model wasused to test whether this increasingly widely used modelling approach provides an adequate represen-tation of the statistical characteristics the most comprehensive dataset of metered electricity demandavailable in the UK. Both the empirical and simulated electricity consumption data have been analysedon an aggregated level, paying special attention to the mean daily load profiles, the distribution of house-holds with respect to the total annual demands, and the distributions of the annual demands of particularappliances. A thorough comparison making use of both qualitative and quantitative methods was madebetween simulated datasets and it’s metered counterparts. Significant discrepancies were found in thedistribution of households with respect to both overall electricity consumption and consumption ofindividual appliances. Parametric estimates of the distributions of metered data were obtained, and theanalytic expressions for both the density function and cumulative distribution are given. These can beincorporated into new and existent modelling frameworks, as well as used as tools for further analysis

The targeted delivery of multicomponent cargos to cancer cells by nanoporous particle-supported lipid bilayers.

Encapsulation of drugs within nanocarriers that selectively target malignant cells promises to mitigate side effects of conventional chemotherapy and to enable delivery of the unique drug combinations needed for personalized medicine. To realize this potential, however, targeted nanocarriers must simultaneously overcome multiple challenges, including specificity, stability and a high capacity for disparate cargos. Here we report porous nanoparticle-supported lipid bilayers (protocells) that synergistically combine properties of liposomes and nanoporous particles. Protocells modified with a targeting peptide that binds to human hepatocellular carcinoma exhibit a 10,000-fold greater affinity for human hepatocellular carcinoma than for hepatocytes, endothelial cells or immune cells. Furthermore, protocells can be loaded with combinations of therapeutic (drugs, small interfering RNA and toxins) and diagnostic (quantum dots) agents and modified to promote endosomal escape and nuclear accumulation of selected cargos. The enormous capacity of the high-surface-area nanoporous core combined with the enhanced targeting efficacy enabled by the fluid supported lipid bilayer enable a single protocell loaded with a drug cocktail to kill a drug-resistant human hepatocellular carcinoma cell, representing a 10(6)-fold improvement over comparable liposomes