Multiple Classifier Systems for Hyperspectral Remote Sensing Data Classification

One of the most widely used outputs of remote sensing technology is Hyperspectral image. This large amount of information can increase classification accuracy. But at the same time, conventional classification techniques are facing the problem of statistical estimation in high-dimensional space. Recently in remote sensing, support vector machines (SVMs) have shown very suitable performance in classifying high dimensionality problem. Another strategy that has recently been used in remote sensing is multiple classifier system (MCS). It can also improve classification accuracy by combining different classifier methods or by a diversity of the same classifier. This paper aims to classify a Hyperspectral data using the most common methods of multiple classifier systems i.e. adaboost and bagging and a MCS based on SVM. The data used in the paper is an AVIRIS data with 224 spectral bands. The final results show the high capability of SVMs and MCSs in classifying high dimensionality data.     

The middle Eocene high-K magmatism in Eastern Iran Magmatic Belt: constraints from U-Pb zircon geochronology and Sr-Nd isotopic ratios

ABSTRACT

Intrusive rocks are well-exposed in the south Birjand around the Koudakan is herein compared to previously studied outcrops along the middle Eocene to late Oligocene Eastern Iran Magmatic Belt. This pluton is composed mainly of monzonite, quartz-monzonite, and granite with high-K calc-alkaline to shoshonitic affinities. The U-Pb zircon geochronology from monzonite and quartz-monzonite reveals the crystallization ages of 40.96 ± 0.48 to 38.78 ± 0.78 Ma (Bartonian). The monzonite, quartz-monzonite, and granite rocks show similar REEs and trace element patterns, as well as limited variations in εNd_(i) and ⁸⁷Sr/⁸⁶Sr_(i) ratio, suggesting that they are a comagmatic intrusive suite. The chondrite and primitive mantle normalized rare earth and trace element patterns show enrichment in the light rare earth elements, K, Rb, Cs, Pb, Th, and U and depletion in heavy rare earth elements, Nb, Zr, and Ti. The εNd_(i) and ⁸⁷Sr/⁸⁶Sr_(i) values range from +1.32 to +1.68 and 0.7044 to 0.7047, respectively, identical to island-arc basalt composition. The whole-rock Nd model age (T_DM) for the intrusive rocks range between 0.69 and 0.73 Ga. These geochemical and isotopic signatures indicate a subduction-related sub-continental lithospheric mantle source for these rocks. Our new geochemical, isotopic, and geochronological studies integrated with previously published data indicate that the middle Eocene to late Oligocene magmatism in eastern Iran was formed in a post-collisional tectonic environment. We suggest the northeastward subduction of the Neo-Tethys ocean beneath the Lut block and the eastward subduction of the Sistan ocean beneath the Afghan block caused mantle wedge to be metasomatized by slab components. At a later stage, a collision between the Lut and Afghan blocks was accompanied by the lithospheric delamination, and the subsequent asthenospheric upwelling led to the melting of the metasomatized sub-continental lithospheric mantle and the generation of middle Eocene to late Oligocene magmatism in the Eastern Iran Magmatic Belt.     

Strength and Compressibility Characteristics of a Soft Clay Subjected to Ground Treatment

The compressibility properties, undrained shear strength, and stress history are essential for reliable calculations of settlement and bearing capacity of soft soils. However, it is sometimes a challenge to determine representative parameters for very soft and high plasticity clays, which are often found in Brazilian coastal areas. In this study an extensive site investigation was planned aiming to interpret the behaviour of a trial embankment on stabilized soft ground. The site investigation was carried out in a test area located in the west of city of Rio de Janeiro, consisted of three clusters in which standard penetration tests, vane shear tests, and piezocone tests (CPTu) were performed. A number of correlations was developed and compared with empirical equations in order to verify their reliability. The results of these tests made it possible to define geotechnical parameters of the soft clay to use in the numerical and analytical computations of the embankment on reinforced ground.     

System identification and modeling of a dynamically tested and gradually damaged 10‐story reinforced concrete building

This paper discusses the dynamic tests, system identification, and modeling of a 10‐story reinforced concrete building. Six infill walls were demolished in 3 stages during the tests to introduce damage. In each damage stage, dynamic tests were conducted by using an eccentric‐mass shaker. Accelerometers were installed to record the torsional and translational responses of the building to the induced excitation, as well as its ambient vibration. The modal properties in all damage states are identified using 2 operational modal analysis methods that can capture the effect of the wall demolition. The modal identification is facilitated by a finite element model of the building. In turn, the model is validated through the comparison of the numerically and experimentally obtained modal parameters. The validated model is used in a parametric study to estimate the influence of structural and nonstructural elements on the dynamic properties of the building and to assess the validity of commonly used empirical formulas found in building codes. Issues related to the applicability and feasibility of system identification on complex structures, as well as considerations for the development of accurate, yet efficient, finite element models are also discussed.     

海草凋落叶的溶解有机物的释放及其生物地球化学意义

Dissolved organic matter(DOM) represents a significant source of nutrients that supports the microbial-based food web in seagrass ecosystems. However, there is little information on how the various fractions of DOM from seagrass leaves contributed to the coastal biogeochemical cycles. To address this gap, we carried out a 30-day laboratory chamber experiment on tropical seagrasses Thalassia hemprichii and Enhalus acoroides. After 30 days of incubation, on average 22% carbon(C), 70% nitrogen(N) and 38% phosphorus(P) of these two species of seagrass leaf litter was released. The average leached dissolved organic carbon(DOC), dissolved organic nitrogen(DON) and dissolved organic phosphorus(DOP) of these two species of seagrass leaf litter accounted for 55%, 95% and 65% of the total C, N and P lost, respectively. In the absence of microbes, about 75% of the total amount of DOC, monosaccharides(MCHO), DON and DOP were quickly released via leaching from both seagrass species in the first 9 days. Subsequently, little DOM was released during the remainder of the experiment. The leaching rates of DOC, DON and DOP were approximately 110, 40 and 0.70 μmol/(g·d). Leaching rates of DOM were attributed to the nonstructural carbohydrates and other labile organic matter within the seagrass leaf. Thalassia hemprichii leached more DOC, DOP and MCHO than E. acoroides. In contrast, E. acoroides leached higher concentrations of DON than T. hemprichii, with the overall leachate also having a higher DON: DOP ratio. These results indicate that there is an overall higher amount of DOM leachate from T. hemprichii than that of E. acoroides that is available to the seagrass ecosystem. According to the logarithmic model for DOM release and the in situ leaf litter production(the Xincun Bay, South China Sea), the seagrass leaf litter of these two seagrass species could release approximately 4×10~3 mol/d DOC, 1.4×10~3 mol/d DON and 25 mol/d DOP into the seawater. In addition to providing readily available nutrients for the microbial food web, the remaining particulate organic matter(POM)from the litter would also enter microbial remineralization processes. What is not remineralized from either DOM or POM fractions has potential to contribute to the permanent carbon stocks.     

Inverse problem theory to chemo-poroelastic parameters estimation: an analytical/experimental investigation

Shale formation swelling is one of the main factors affecting wellbore instability and associated problems in drilling operation. In order to eliminate these problems, it is important to investigate formation characteristics and understand mechanisms of rock-fluid interaction, from chemical/mechanical point of view. Shale membrane efficiency is known as an important parameter affecting wellbore instability. In order to measure this parameter, many mathematical models and experimental efforts have been carried out which consider mechanical-chemical processes for rock-fluid interactions. In this study, the field equations governing the problem have been derived based on the linear chemo-poroelastic theory and solved using analytical/numerical methods. Afterward, a comprehensive workflow to characterize the chemo-poroelastic parameters of illite-rich shale is conducted in the laboratory. In fact, mineralogical and apparent properties of shale sample have been described and some setups were performed such as triaxial test and membrane efficiency. Then genetic algorithm has been applied to solve an inverse problem and get a match between experimental data and modeling results. Ultimately, the three important properties in shale-fluid interactions, i.e., shale membrane efficiency, hydraulic, and chemical diffusivity coefficient have been estimated. Comparing the simulation results with the experimental data indicates that the simulation model can appropriately simulate the pore pressure transmission test. With this approach, the required parameters can be estimated with good accuracy without using time-consuming and costly tests.     

Analytical 3D transient elastodynamic fundamental solution of unsaturated soils

Unsaturated soils are considered as porous continua, composed of porous skeleton with its pores filled by water and air. The governing partial differential equations (PDE) are derived based on the mechanics for isothermal and infinitesimal evolution of unsaturated porous media in terms of skeleton displacement vector, liquid, and gas scalar pressures. Meanwhile, isotropic linear elastic behavior and liquid retention curve are presented in terms of net stress and capillary pressure as constitutive relations. Later, an explicit 3D Laplace transform domain fundamental solution is obtained for governing PDE and then closed‐form analytical transient 3D fundamental solution is presented by means of analytical inverse Laplace transform technique. Finally, a numerical example is presented to validate the assumptions used to derive the analytical solution by comparing them with the numerically inverted ones. The transient fundamental solutions represent important features of the elastic wave propagation theory in the unsaturated soils. Copyright © 2010 John Wiley & Sons, Ltd.     

The generalized second law for the interacting generalized Chaplygin gas model in non-flat universe enclosed by the apparent horizon

We investigate the validity of the generalized second law of gravitational thermodynamics in a non-flat FRW universe containing the interacting generalized Chaplygin gas with the baryonic matter. The boundary of the universe is assumed to be enclosed by the dynamical apparent horizon. We show that for the interacting generalized Chaplygin gas as a unified candidate for dark matter and dark energy, the equation of state parameter can cross the phantom divide. We also present that for the selected model under thermal equilibrium with the Hawking radiation, the generalized second law is always satisfied throughout the history of the universe for any spatial curvature, independently of the equation of state of the interacting generalized Chaplygin gas model.