Recovery of polarimetric Stokes images by spatial mixture models

A Bayesian approach for joint restoration and segmentation of polarization encoded images is presented with emphasis on both physical admissibility and smoothness of the solution. Two distinct models for the sought polarized radiances are used: (i) the polarized light at each site of the image is described by its Stokes vector, which directly follows a mixture of truncated Gaussians, explicitly assigning zero probability to inadmissible configurations and (ii) polarization at each site is represented by the coherency matrix, which is parameterized by a set of variables assumed to be generated by a spatially varying mixture of Gaussians. Application on real and synthetic images using the proposed methods assesses the pertinence of the approach.     

Effects of olive pomace and olive pomace oil on growth performance,fatty acid composition and cardio protective properties of gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax)

Gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) were fed with two experimental diets: olive pomace diet and olive pomace oil diet, in order to examine whether fish oil substitution in fish feeds by olive oil production wastes, such as olive pomace and olive pomace oil, has an influence on growth performance, fatty acid composition and cardio protective properties of fish. Gilthead sea bream fed with both experimental diets exhibited satisfactory growth performance factors while sea bass did not. The total lipids of gilthead sea bream fed with olive pomace diet contained statistically decreased levels of fatty acids, while exhibited the most potent biological activity against platelet aggregation induced by Platelet Activating Factor. These data indicate that olive pomace can be used as a partial substitute of fish oil in fish feed improving its cardio protective properties.     

Multitemporal Monitoring of Land Degradation Risk Due to Soil Loss in a Fire-Prone Mediterranean Landscape Using Multi-decadal Landsat Imagery

Water Resources Management - Natural, as well as human-induced, landscape changes may have profound effects on soil-loss rates in Mediterranean countries. Knowledge of the spatial and temporal...     

Hough Pyramid Matching: Speeded-Up Geometry Re-ranking for Large Scale Image Retrieval

Exploiting local feature shape has made geometry indexing possible, but at a high cost of index space, while a sequential spatial verification and re-ranking stage is still indispensable for large scale image retrieval. In this work we investigate an accelerated approach for the latter problem. We develop a simple spatial matching model inspired by Hough voting in the transformation space, where votes arise from single feature correspondences. Using a histogram pyramid, we effectively compute pair-wise affinities of correspondences without ever enumerating all pairs. Our Hough pyramid matching algorithm is linear in the number of correspondences and allows for multiple matching surfaces or non-rigid objects under one-to-one mapping. We achieve re-ranking one order of magnitude more images at the same query time with superior performance compared to state of the art methods, while requiring the same index space. We show that soft assignment is compatible with this matching scheme, preserving one-to-one mapping and further increasing performance.     

Assessing the impact of training sample selection on accuracy of an urban classification: a case study in Denver,Colorado

Understanding the factors that influence the performance of classifications over urban areas is of considerable importance to applications of remote-sensing-derived products in urban design and planning. We examined the impact of training sample selection on a binary classification of urban and nonurban for the Denver, Colorado, metropolitan area. Complete coverage reference data for urban and nonurban cover were available for the year 1997, which allowed us to examine variability in accuracy of the classification over multiple repetitions of the training sample selection and classification process. Four sampling designs for selecting training data were evaluated. These designs represented two options for stratification (spatial and class-specific) and two options for sample allocation (proportional to area and equal allocation). The binary urban and nonurban classification was obtained by employing a decision tree classifier with Landsat imagery. The decision tree classifier was applied to 1000 training samples selected by each of the four training data sampling designs, and accuracy for each classification was derived using the complete coverage reference data. The allocation of sample size to the two classes had a greater effect on classifier performance than the spatial distribution of the training data. The choice of proportional or equal allocation depends on which accuracy objectives have higher priority for a given application. For example, proportionally allocating the training sample to urban and nonurban classes favoured user’s accuracy of urban whereas equally allocating the training sample to the two classes favoured producer’s accuracy of urban. Although this study focused on urban and nonurban classes, the results and conclusions likely generalize to any binary classification in which the two classes represent disproportionate areas.     

Nonequilibrium Gas Flow and Heat Transfer in a Heated Square Microcavity

The flow of a rarefied gas in a square enclosure with one wall at high temperature and the other three walls at the same low temperature is investigated. The flow, characterized by the reference Knudsen number and ratio of the cold over the hot temperatures, is simulated both deterministically, using the nonlinear Shakhov kinetic model, and stochastically, using the DSMC method. Excellent agreement between the two approaches is obtained. It is found that along the side walls the gas velocity, depending on the flow parameters, may be either from cold to hot or from hot to cold regions. Furthermore, it is confirmed that the average heat flux departing from the hot plate exhibits a nonmonotonic behavior with regard to the temperature ratio, deducing a maximum heat flux at a temperature ratio of about 0.3. The flow and heat transfer characteristics are explained by computing the ballistic and collision parts of the total bulk quantities and by investigating the contribution of each part to the overall solution.     

House of Affects—time,immersion and play in digital design for spatially-experienced interactive narrative

Abstract

Philosophers and architects have beeninvestigating how human presence is integrated into ‘constructed realities’for many years. Architects now need tolook to cinema for ways of connecting disparate spaces and relating them through movement, and in time. Framing interactive experience with the help of Stanislavskian categories and building story-blocks into games, brings narrative, dramatic and emotional‘added value’ to the process of immersion in cinematic fiction. By prototyping an easily-adaptable modelof architecture for audiovisualspace, the experimental project House of Affects aims to create a matrix of construction for spaces for cinematic interactive experience.     

One-dimensional model of solar thermal reactors for the co-production of hydrogen and carbon black from methane decomposition

The solar thermal decomposition of methane is a promising route for the large scale production of hydrogen and carbon black with zero CO₂ emissions, however careful control of the reactor is required to ensure product particles of specific sizes. A one-dimensional model employing a sectional method is developed to simulate the evolution of polydisperse fresh and seed particle populations in an indirectly heated solar reactor. The model accounts for the homogeneous nucleation of fresh particles, the heterogeneous growth of the fresh and seed particles, particle coagulation, and the growth of carbon on the walls of the reactor from heterogeneous reaction and particle deposition. The heat transport mechanisms modelled include wall-gas convection, wall-particle radiation exchange, particle-gas convection and heat release from chemical reaction. The model is validated in terms of methane conversion against a 10 kW experimental solar reactor and used to extract kinetic parameters for the homogeneous and heterogeneous reaction paths. The model shows promise as a quick and simple tool for the design and control of industrial scale solar reactors.