Space-efficient representations of rectangle datasets supporting orthogonal range querying

The increasing use of geographic search engines manifests the interest of Internet users in geo-located resources and, in general, in geographic information. This has emphasized the importance of the development of efficient indexes over large geographic databases. The most common simplification of geographic objects used for indexing purposes is a two-dimensional rectangle. Furthermore, one of the primitive operations that must be supported by every geographic index structure is the orthogonal range query, which retrieves all the geographic objects that have at least one point in common with a rectangular query region. In this work, we study several space-efficient representations of rectangle datasets that can be used in the development of geographic indexes supporting orthogonal range queries.     

New bounds on D-ary optimal codes

We propose a simple method that, given a symbol distribution, yields upper and lower bounds on the average code length of a D-ary optimal code over that distribution. Thanks to its simplicity, the method permits deriving analytical bounds for families of parametric distributions. We demonstrate this by obtaining new bounds, much better than the existing ones, for Zipf and exponential distributions when D>2.     

Linear bases for spectral reflectance functions of acrylic paints

A linear model for representing reflectances has been developed from a group of 5574 samples of acrylic paint on paper. Using acrylic paints makes easy the generation of a large variety of samples by mixing, due to the high miscibility among these kinds of pigments: this point was the key to achieve a great spatial homogeneity in our samples. Besides, these kinds of paints keep their chromatic properties stable over time. The first 7 vectors of the so-called overall linear basis were sufficient for a more than adequate mathematical representation of the spectral-reflectance curves. A study by hue groups of the mathematical properties of these curves indicates that the use of a hue basis of representation implies, on the average, a reduction in 1 or 2 of the number of vectors needed in order to achieve results analogous to those of the overall basis. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 39–45, 1998     

Multispectral synthesis of daylight using a commercial digital CCD camera

Performance of multispectral devices in recovering spectral data has been intensively investigated in some applications, as in spectral characterization of art paintings, but has received little attention in the context of spectral characterization of natural illumination. This study investigated the quality of the spectral estimation of daylight-type illuminants using a commercial digital CCD camera and a set of broadband colored filters. Several recovery algorithms that did not need information about spectral sensitivities of the camera sensors nor eigenvectors to describe the spectra were tested. Tests were carried out both with virtual data, using simulated camera responses, and real data obtained from real measurements. It was found that it is possible to recover daylight spectra with high spectral and colorimetric accuracy with a reduced number of three to nine spectral bands.     

A semantic approach to optimize linear datalog programs

In this work, we present a semantic query optimization approach to improve the efficiency of the evaluation of a subset of SQL:1999 recursive queries. Using datalog notation, we can state our main contribution as an algorithm that builds a program P′ equivalent to a given program P, when both are applied over a database d satisfying a set of functional dependencies. The input program P is a linear recursive datalog program. The new program P′ has less different variables and, sometimes, less atoms in rules, thus it is cheaper to evaluate. Using coral and ibm db2, P′ is empirically shown to be more efficient than the original program.This work is partially supported by Xunta de Galicia grant PGIDIT05SIN10502PR and Ministerio de Educación y Ciencia (PGE y FEDER) grants TIC2003-06593 and TIN2006-15071-C03-03.     

Photocatalytic Activity of Metalloporphyrin–Titanium Mixtures in Microemulsions

This report explores the photocatalytic activity of TiO₂, Ti(IV) citrate and Zn(II) tetraphenyl porphyrin (ZnTPP) and its mixtures in water/oil (W/O) and O/W microemulsion (μE). The 4-chlorophenol was used to assess the efficiency of the photoactive compounds in a degradation process. A simple photoelectrochemical study based on cyclic voltammetry was also developed. The results revealed that most of the photocatalytic procedures developed are effective in the degradation process. However, phenol was the major product obtained.     

Adequacy of different wheat cultivars for low-hydration bread making

BACKGROUND: There is considerable interest in recovering landraces as genetic resources and as raw materials in ecological production. Low-hydration bread, whose dough is submitted to a sheeting roll process, is commonly prepared in Spain and other countries. The aim of this study was to assess the adequacy of some landraces, compared with commercial cultivars and flours, for making this type of bread. Eight Spanish landraces, four wheat cultivars developed during the green revolution and three commercial flours were chosen, their alveographic and kneading behaviours were analysed and the characteristics of the resulting breads were determined. RESULTS: The best correlations were obtained in breads with improver. Flours with extreme alveographic behaviour differed markedly from the rest. When these flours were excluded from the analysis, the parameters best correlated with bread quality (when using improver) were strength, tenacity and development time. A significant correlation between flour colour, a genetic factor, and crumb colour was found. This correlation was higher in breads without improver. CONCLUSION When flours with extreme characteristics were removed, the protein quality characteristics of flours defined the quality characteristics of low-hydration breads.     

Effect of storage on non‐enzymatic browning of liquid infant milk formulae

Furfural, hydroxymethylfurfural (HMF), furosine, lactulose, ascorbic acid and absorbance at 284 and 420 nm (A₂₈₄ and A₄₂₀) were all determined in two types of liquid infant formula prepared with different processing protocols. These browning indicators were used to assess the effects of storage and modified atmosphere on the shelf‐life of infant formulae. The study was carried out at 20 and 55 °C for 15, 30 and 90 days. At 20 °C, slight browning was observed and could be evaluated by furosine, furfural and total HMF indicators. At 55 °C, formula type A (pasteurised, spray‐dried and reconstituted) showed more browning in nitrogen storage conditions than did type B. Furfural, HMF, lactulose, A₂₈₄ and A₄₂₀ are useful indicators to control the extent of browning reactions in adverse storage conditions. © 2002 Society of Chemical Industry     

Environmental benefits of parking‐integrated photovoltaics: a 222 kWp experience

The life cycle assessment of a grid‐connected, parking integrated, 222 kW_p cadmium telluride photovoltaic system has been performed. The system was built at the University of Murcia and has been monitored for 2.5 years (sampling data every 5 min). The detailed material inventory, the energy embedded in the system, the energy payback time, and the energy return factor of the facility have been obtained and are 6.31 TJ equivalent primary energy, 2.06 and 12.16years, respectively. The average performance ratio is 0.8 with a slight monthly variation. Additionally, the environmental benefits of the architectural integration (in this case parking integration) have been quantified using a standard methodology for the calculation of several environmental parameters. Finally, the environmental benefits of renewable energy generation because of the savings of producing the same amount of electricity by the Spanish grid system have been assessed. Copyright © 2013 John Wiley & Sons, Ltd.