4,374 research outputs found
Probabilistic Search for Object Segmentation and Recognition
The problem of searching for a model-based scene interpretation is analyzed
within a probabilistic framework. Object models are formulated as generative
models for range data of the scene. A new statistical criterion, the truncated
object probability, is introduced to infer an optimal sequence of object
hypotheses to be evaluated for their match to the data. The truncated
probability is partly determined by prior knowledge of the objects and partly
learned from data. Some experiments on sequence quality and object segmentation
and recognition from stereo data are presented. The article recovers classic
concepts from object recognition (grouping, geometric hashing, alignment) from
the probabilistic perspective and adds insight into the optimal ordering of
object hypotheses for evaluation. Moreover, it introduces point-relation
densities, a key component of the truncated probability, as statistical models
of local surface shape.Comment: 18 pages, 5 figure
Cardiovascular disease risk factor responses to a type 2 diabetes care model including nutritional ketosis induced by sustained carbohydrate restriction at 1 year: An open label, non-randomized, controlled study
Additional file 1: Table S1. Detailed baseline characteristics for participants in the continuous care intervention (CCI) and usual care (UC) groups
Aerobic Capacity and Postprandial Flow Mediated Dilation
The consumption of a high-fat meal induces transient vascular dysfunction. Aerobic exercise enhances vascular function in healthy individuals. Our purpose was to determine if different levels of aerobic capacity impact vascular function, as measured by flow mediated dilation, following a high-fat meal. Flow mediated dilation of the brachial artery was determined before, two- and four-hours postprandial a high-fat meal in young males classified as highly trained (n = 10; VO2max = 74.6 ± 5.2 ml·kg·min-1) or moderately active (n = 10; VO2max = 47.3 ± 7.1 ml·kg·min-1). Flow mediated dilation was reduced at two- (p \u3c 0.001) and four-hours (p \u3c 0.001) compared to baseline for both groups but was not different between groups at any time point (p = 0.108). Triglycerides and insulin increased at two- (p \u3c 0.001) and four-hours (p \u3c 0.05) in both groups. LDL-C was reduced at four-hours (p = 0.05) in highly trained subjects, and two- and four-hours (p ≤ 0.01) in moderately active subjects. HDL-C decreased at two- (p = 0.024) and four-hours (p = 0.014) in both groups. Glucose increased at two-hours postprandial for both groups (p = 0.003). Our results indicate that a high-fat meal results in reduced endothelium-dependent vasodilation in highly trained and moderately active individuals with no difference between groups. Thus, high aerobic capacity does not protect against transient reductions in vascular function after the ingestion of a single high-fat meal compared to individuals who are moderately active
Models and metaphors: complexity theory and through-life management in the built environment
Complexity thinking may have both modelling and metaphorical applications in the through-life management of the built environment. These two distinct approaches are examined and compared. In the first instance, some of the sources of complexity in the design, construction and maintenance of the built environment are identified. The metaphorical use of complexity in management thinking and its application in the built environment are briefly examined. This is followed by an exploration of modelling techniques relevant to built environment concerns. Non-linear and complex mathematical techniques such as fuzzy logic, cellular automata and attractors, may be applicable to their analysis. Existing software tools are identified and examples of successful built environment applications of complexity modelling are given. Some issues that arise include the definition of phenomena in a mathematically usable way, the functionality of available software and the possibility of going beyond representational modelling. Further questions arising from the application of complexity thinking are discussed, including the possibilities for confusion that arise from the use of metaphor. The metaphor of a 'commentary machine' is suggested as a possible way forward and it is suggested that an appropriate linguistic analysis can in certain situations reduce perceived complexity
Cross Sections from 800 MeV Proton Irradiation of Terbium
A single terbium foil was irradiated with 800 MeV protons to ascertain the
potential for production of lanthanide isotopes of interest in medical,
astrophysical, and basic science research and to contribute to nuclear data
repositories. Isotopes produced in the foil were quantified by gamma
spectroscopy. Cross sections for 36 isotopes produced in the irradiation are
reported and compared with predictions by the MCNP6 transport code using the
CEM03.03, Bertini, and INCL+ABLA event generators. Our results indicate the
need to accurately consider fission and fragmentation of relatively light
target nuclei like terbium in the modeling of nuclear reactions at 800 MeV. The
predictive power of the code was found to be different for each event generator
tested but was satisfactory for most of the product yields in the mass region
where spallation reactions dominate. However, none of the event generators'
results are in complete agreement with measured data.Comment: 16 pages, 3 figures, 1 tables, only pdf, submitted to Nuclear Physics
Le projet DYLAN ou les enjeux politiques, cognitifs et stratégiques du plurilinguisme
Composed of 19 universities from 12 countries, the Dylan Project is an integrated project (IP) of the 6th Framework Programme of the European Union, under Priority 7 « Citizenship and governance in a knowledge-based society ».The project addresses the core issue underlying topic 3.3.1: establish whether and how a European knowledge based society designed to ensure economic competitiveness and social cohesion can be created within a European Union that is linguistically more diverse than ever. The overarching objectives are to show that, in this respect, the linguistic diversity prevalent in Europe is potentially an asset rather than an obstacle and to identify the conditions under which individual and societal multilingualism can be turned to advantage.It will show in what ways the usage of multilingual repertoires can promote the creation and the transfer of knowledge (cognitive asset) and have an impact on communication control, problem solving and decision making (strategic asset), in the diversity of economic, political and educational contexts
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Ensemble prediction for nowcasting with a convection-permitting model—I: description of the system and the impact of radar-derived surface precipitation rates
A key strategy to improve the skill of quantitative predictions of precipitation, as well as hazardous weather such as severe thunderstorms and flash floods is to exploit the use of observations of convective activity (e.g. from radar). In this paper, a convection-permitting ensemble prediction system (EPS) aimed at addressing the problems of forecasting localized weather events with relatively short predictability time scale and based on a 1.5 km grid-length version of the Met Office Unified Model is presented. Particular attention is given to the impact of using predicted observations of radar-derived precipitation intensity in the ensemble transform Kalman filter (ETKF) used within the EPS. Our initial results based on the use of a 24-member ensemble of forecasts for two summer case studies show that the convective-scale EPS produces fairly reliable forecasts of temperature, horizontal winds and relative humidity at 1 h lead time, as evident from the inspection of rank histograms. On the other hand, the rank histograms seem also to show that the EPS generates too much spread for forecasts of (i) surface pressure and (ii) surface precipitation intensity. These may indicate that for (i) the value of surface pressure observation error standard deviation used to generate surface pressure rank histograms is too large and for (ii) may be the result of non-Gaussian precipitation observation errors. However, further investigations are needed to better understand these findings. Finally, the inclusion of predicted observations of precipitation from radar in the 24-member EPS considered in this paper does not seem to improve the 1-h lead time forecast skill
Hyperbolic planforms in relation to visual edges and textures perception
We propose to use bifurcation theory and pattern formation as theoretical
probes for various hypotheses about the neural organization of the brain. This
allows us to make predictions about the kinds of patterns that should be
observed in the activity of real brains through, e.g. optical imaging, and
opens the door to the design of experiments to test these hypotheses. We study
the specific problem of visual edges and textures perception and suggest that
these features may be represented at the population level in the visual cortex
as a specific second-order tensor, the structure tensor, perhaps within a
hypercolumn. We then extend the classical ring model to this case and show that
its natural framework is the non-Euclidean hyperbolic geometry. This brings in
the beautiful structure of its group of isometries and certain of its subgroups
which have a direct interpretation in terms of the organization of the neural
populations that are assumed to encode the structure tensor. By studying the
bifurcations of the solutions of the structure tensor equations, the analog of
the classical Wilson and Cowan equations, under the assumption of invariance
with respect to the action of these subgroups, we predict the appearance of
characteristic patterns. These patterns can be described by what we call
hyperbolic or H-planforms that are reminiscent of Euclidean planar waves and of
the planforms that were used in [1, 2] to account for some visual
hallucinations. If these patterns could be observed through brain imaging
techniques they would reveal the built-in or acquired invariance of the neural
organization to the action of the corresponding subgroups.Comment: 34 pages, 11 figures, 2 table
Evolutionary Analysis of Mitogenomes from Parasitic and Free-Living Flatworms
Copyright: © 2015 Solà et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article
Delivering green streets: an exploration of changing perceptions and behaviours over time around bioswales in Portland, Oregon
Green Infrastructure (GI) is an increasingly popular means of dealing with flooding and water quality issues worldwide. This study examines public perceptions of, and behaviour around, bioswales, which are a popular GI facility in the United States. Bioswales are highly visible interventions requiring support from residents and policy‐makers to be implemented and maintained appropriately. To understand how the residents' perceptions and attitudes might develop over time, we interviewed residents of Portland, Oregon, living near bioswales installed 1–2, 4–5 and 8–9 years ago, to determine awareness, understanding, and opinions about the devices. We found no consistent patterns across time periods, but did find common issues affecting residents' appreciation and acceptance: environmental attitudes, awareness and understanding of purpose and function, plant choice and maintenance, and mess and littering. It was apparent that increased public engagement, localised maintenance strategies, and possibly even customising facilities to meet residents' needs where feasible, might improve acceptance
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