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101.
Modeling and querying moving objects in networks 总被引:11,自引:0,他引:11
Ralf Hartmut Güting Victor Teixeira de Almeida Zhiming Ding 《The VLDB Journal The International Journal on Very Large Data Bases》2006,15(2):165-190
Moving objects databases have become an important research issue in recent years. For modeling and querying moving objects,
there exists a comprehensive framework of abstract data types to describe objects moving freely in the 2D plane, providing
data types such as moving point or moving region. However, in many applications people or vehicles move along transportation networks. It makes a lot of sense to model the
network explicitly and to describe movements relative to the network rather than unconstrained space, because then it is much
easier to formulate in queries relationships between moving objects and the network. Moreover, such models can be better supported
in indexing and query processing. In this paper, we extend the ADT approach by modeling networks explicitly and providing
data types for static and moving network positions and regions. In a highway network, example entities corresponding to these
data types are motels, construction areas, cars, and traffic jams. The network model is not too simplistic; it allows one
to distinguish simple roads and divided highways and to describe the possible traversals of junctions precisely. The new types
and operations are integrated seamlessly into the ADT framework to achieve a relatively simple, consistent and powerful overall
model and query language for constrained and unconstrained movement. 相似文献
102.
C Clayton M Adams R Almeida T Baltz M Barrett P Bastien S Belli S Beverley N Biteau J Blackwell C Blaineau M Boshart F Bringaud G Cross A Cruz W Degrave J Donelson N El-Sayed G Fu K Ersfeld W Gibson K Gull A Ivens J Kelly L Vanhamme 《Canadian Metallurgical Quarterly》1998,97(1-2):221-224
We investigated the effect of chronic ethanol administration and its withdrawal on the polypeptide levels of NMDA receptor subunits such as NR1, NR2A, and NR2B in the rat cerebral cortex and hippocampus using Western blot analysis technique. Our results indicate that chronic ethanol treatment upregulates NMDA receptor subunits NR1, NR2A, and NR2B ( approximately 35%). At 48 h of last dose of ethanol administration, the protein content returned to almost control level, thereby demonstrating the reversibility of the changes. 相似文献
103.
104.
The effects of river regulation on the hydrological cycle of a river and on the respective fish assemblage may differ according to dam operation purpose and type of river analysed. To assess the spatial and temporal variation of fish assemblages and their response to the hydrological changes caused by two different types of flow regulation, we selected three sampling sites in four rivers with different levels of regulation, two in a permanent river system and another two on a temporary one, which we sampled in four different annual seasons. In the permanent system, hydroelectrical regulation decreased hydrological variability, which affected fluvial specialist species, benefitting the generalist ones, and created a more homogeneous community that presented less intra‐annual variation. In the temporary system, agricultural regulation caused an inversion of the hydrological cycle, maintaining a moderate flow volume throughout the drought period that benefited the introduced, generalist and more tolerant species. Monthly volume was recognized, in a temporal scale, as the most important hydrological feature for assemblages’ structure, predicting the intra‐annual variation of several ecological guilds. This study provides important considerations for dam management and riverine ecosystems conservation. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
105.
Sinan Boztepe Rémi Gilblas Olivier de Almeida Christian Gerlach Yannick Le Maoult Fabrice Schmidt 《International Journal of Material Forming》2018,11(5):717-727
Infrared (IR) heating is widely used for thermoforming of thermoplastic polymers. The key benefit of radiation heating is that a significant amount of the radiative energy penetrates into the polymers thanks to their semi-transparency. For the case of heating unfilled semi-crystalline polymers, the relation between their microcrystalline structure and optical properties is the key to develop a predictive IR-heating model as microcrystalline structure introduces an optically heterogeneous medium. In this study, a relation between the microcrystalline structure of a polyethylene (PE) and its effect on the thermo-optical properties was experimentally analyzed considering a two-step analysis. At very first step, the relation was analyzed considering samples with identical thicknesses and different morphologies, characterized here in terms of degree of crystallinity (Xc (%)). Using Fourier Transform Infrared (FT-IR) spectroscopy and integrating sphere, optical characteristics of the PE samples were analyzed in near-infrared (NIR) and middle-infrared (MIR) spectral ranges. The analyses showed that a slight variation in Xc (%) has a great effect on the optical characteristics of PE, particularly the transmission characteristics in NIR range. The wavelength-dependent effect of Xc (%) on the transmission behaviors opened a discussion about the fact that the microcrystalline structures -in particular spherulites or their substructures such as lamellae- are responsible for optical scattering. Using the optical properties obtained from the two-step experimental analyses, two different thermo-optical properties were calculated, namely extinction and absorption coefficients, and used as a numerical input for the parametric numerical studies. The numerical studies were performed using an in-house developed radiation heat transfer algorithm -RAYHEAT-. Both the experimental and numerical analyses demonstrated the importance of the optical scattering regarding the identification of thermo-optical properties, used as a numerical input for radiation heat transfer models. 相似文献
106.
Luzia Shundo Adriana P. de Almeida Janete Alaburda Leda C.A. Lamardo Sandra A. Navas Valter Ruvieri Myrna Sabino 《Food Control》2009,20(12):1099-1102
Seventy paprika samples collected in the city of São Paulo, Brazil, from January to April 2006 were analysed for aflatoxins and ochratoxin A (OTA) using an immunoaffinity column clean-up and HPLC-FLD. For aflatoxins, the limit of quantification (LOQ) were 0.23, 0.23, 0.45 and 0.45 μg/kg for AFB1, AFB2, AFG1 and AFG2, respectively. For OTA the LOQ was 0.80 μg/kg. Aflatoxins were found in 82.9% of samples and AFB1 was detected in 61.4% at levels ranging from 0.5 to 7.3 μg/kg with mean concentration of 3.4 μg/kg. OTA was found in 85.7% at levels ranging from 0.24 to 97.2 μg/kg with mean concentration of 7.0 μg/kg. 相似文献
107.
Neiva Maria Almeida Maria Regina Bueno Franco 《Journal of the science of food and agriculture》2007,87(14):2596-2603
BACKGROUND: The chemical composition of Amazonian fish is extremely variable, being influenced by the season and the type and amount of food. A special interest in the fish oil composition has been developed owing to the presence of essential fatty acids, since this is directly related to human health. This study aimed to investigate the fatty acid composition (FAC) of the total lipid (TL), neutral lipid (NL) and phospholipid (PL) fractions of the dorsal muscle and orbital cavity of farmed and wild matrinxã in the Amazon area captured in different seasons. RESULTS: Fatty acids (FA) were analysed by high‐resolution gas chromatography/mass spectrometry. Sixty‐five FA were detected in the TL, 66 in the NL and 55 in the PL. The main FA found in farmed and wild fish were oleic, palmitic, stearic and linoleic acids. No distinctions in the quality or quantity of these fractions between dorsal muscle and orbital cavity were found. CONCLUSION: The season had a significant influence on the TL and FAC. Fish captured during the dry season showed lower levels of lipid and a higher percentage of long‐chain polyunsaturated fatty acids. Matrinxã farmed in a semi‐intensive system showed a nutritional quality comparable to that of wild matrinxã captured in the wet season. Copyright © 2007 Society of Chemical Industry 相似文献
108.
Aline Bruna da Silva Celio Wisniewski Jo?o Victor Almeida Esteves Rinaldo Gregorio 《Journal of Materials Science》2010,45(15):4206-4215
Poly(vinylidene fluoride), PVDF, samples containing exclusively the polar β phase were obtained by crystallization from N,N-dimethylformamide (DMF) solution at 60 °C and subsequent pressing. Some of these samples were uniaxially drawn at 120 °C
at draw ratio of 4, resulting in oriented films. Oriented and unoriented samples were characterized as to relative fraction
of β phase, degree of crystallinity and orientation by infrared spectroscopy (FTIR), differential scanning calorimetry (DSC),
and wide-angle X-ray diffraction (WAXD). The dependence on frequency of the real (
e\textr¢ \varepsilon_{\text{r}}^{\prime} ) and imaginary (
e\textr¢¢ \varepsilon_{\text{r}}^{\prime\prime} ) components of the relative permittivity of the samples was determined between 104 and 1.7 × 107 Hz. The coercive field and stable and metastable remanent ferroelectric polarization were determined from the hysteresis
loop obtained by the ramp voltage technique, described in detail in this work. The results allowed verification of the effect
of drawing on structure and of the resulting structure on the dielectric properties, remanent polarization, and coercive field
of β-PVDF. A possible effect of the crystal–amorphous interphase region on the metastable remanent polarization is suggested.
The results obtained with the oriented and unoriented samples were compared with those obtained for films commercialized by
Piezotech S.A. 相似文献
109.
Nathália Maria P. Rocha e Silva Fabíola Carolina G. Almeida Fernanda Cristina P. Rocha e Silva Juliana M. Luna Leonie A. Sarubbo 《Journal of surfactants and detergents》2020,23(6):1111-1123
The use of toxic petroleum-based heavy oils is common in industrial processes. The cleaning of machines, equipment, and other surface covered in these oils is achieved with expensive products that are often also toxic and harmful to both the health of workers and the environment. The present paper proposes the development of a sustainable biodetergent made from plant-based materials. Tests were performed to determine the properties of the biodetergent in terms of its surfactant and emulsifying capacities, stability, toxicity, and the removal of heavy oil from glass plates and metallic surfaces. The formulation was composed of a natural solvent (cottonseed oil), a plant-based surfactant agent (saponin), and two natural stabilizers (carboxymethylcellulose and glycerine). The formulation was stable, nontoxic, and highly efficient, removing 100% of the heavy oil from glass and metallic surfaces. This solution developed in this study could be used in diverse industries with the need to clean machines and parts encrusted with oil and grease as well as the cleaning of floors covered with petroleum-based residues. A preliminary analysis of the economic feasibility of using the detergent was carried out at a Brazilian power plant. Besides the reduction in environmental impact due to the use of a nontoxic, biodegradable product as well as the reduction in health risks to workers associated with toxic cleaning products, this new product can have a considerable impact on the market as an environmentally friendly solution. 相似文献
110.
Presents a new one-memory quaternary four-state trellis code, and its four-state binary equivalent code based on a QAM constellation which is 0.52 dB better than the four-state Ungerboeck code.<> 相似文献