A comparative study on radiometric normalization using high resolution satellite images

Remotely sensed multitemporal, multisensor data are often required in Earth observation applications. A common problem associated with the use of multisource image data is the grey value differences caused by non‐surface factors such as different illumination, atmospheric, or sensor conditions. Such differences make it difficult to compare images using the same colour metric system. Image normalization is required to reduce the radiometric influences caused by non‐surface factors and to ensure that the grey value differences between temporal images reflect actual changes on the surface of the Earth.A variety of image normalization methods, such as pseudoinvariant features (PIF), dark and bright set (DB), simple regression (SR), no‐change set determined from scattergrams (NC), and histogram matching (HM), have been published in scientific journals. These methods have been tested with either Landsat TM data, MSS data or both, and test results differ from author to author. However, whether or not existing methods could be adopted for normalizing high resolution multispectral satellite images, such as IKONOS and QuickBird, is still open for discussion because of the dramatic change in spatial resolution and the difference of available multispectral bands. In this research, the existing methods are introduced and employed to normalize the radiometric difference between IKONOS and QuickBird multispectral images taken in different years. Some improvements are introduced to the existing methods to overcome problems caused by band difference and to achieve more stable and better results. The normalized results are compared in terms of visual inspection and statistical analysis. This paper examined whether or not existing methods can be directly adopted for image normalization with high resolution satellite images, and showed how these methods can be modified for use with such images.     

Bi-modal water transport behavior across a simple Nafion membrane

The development of predictive mathematical models for water management in polymer electrolyte membrane fuel cells requires detailed understanding of water distribution and water transport across the Nafion layer. The anisotropic microstructure of Nafion suggests the measurement of water content and mass transport should be along the fuel cell functional direction, i.e. across the membrane. Non-invasive, high resolution, microscopy measurements of this type are very challenging.We report here the calibration of a minimal mathematical model for diffusive water transport in Nafion against data from high-resolution water content maps determined with a new magnetic resonance imaging methodology developed for this purpose. A mock fuel cell was designed to permit well-controlled wetting and drying boundary conditions. With no chemical potential driving force involved, we assume the water transport behavior will be dominated by diffusion. Moreover we show that, in this context, our model is mathematically equivalent to the traditional permeation models based upon saturation dependent pressure gradients via a capillary pressure ansatz.The non-linear equilibrium water distribution across the Nafion membrane measured in this work suggests a bi-modal diffusivity. The model constructed associates distinct transport behaviors to water contents above and below a critical threshold, consistent with a rearrangement of a micro-structural pore network. The experimental observation and the model prediction agree with the primary features of Weber's model of Nafion, which predicts distinct modes of transport for hydration fronts traversing the through-plane direction of the membrane.     

A combined QXRD/TG method to quantify the phase composition of hydrated Portland cements

A new method is reported for quantifying the mineral phases in hydrated cement pastes that is based on a combination of quantitative X-ray diffractometry (QXRD) and thermogravimetry (TG). It differs from previous methods in that it gives a precise measure of the amorphous phase content without relying on an assumed stoichiometric relationship between the principal hydration products, calcium hydroxide (CH) and calcium silicate hydrate (C–S–H). The method was successfully applied to gray and white ordinary Portland cements (GOPC and WOPC, respectively) that were cured for up to 56 days. Phase distributions determined by QXRD/TG closely matched those from gray-level analysis of backscattered scanning electron microscope (BSEM) images, whereas elemental compositions obtained for the amorphous phase by QXRD/TG agreed well with those measured by quantitative energy dispersive X-ray spectroscopy (EDS).     

Synthesis of WSi2 -SiC composite under the thermally activated combustion mode

Opportunities on combustion synthesizing the WSi2-SiC ceramic composites in a wide range of compositions under the thermal activated mode were studied. Tungsten, silicon powders and carbon black were used as initial reagents, and Magnesium–Teflon mixture was used as an activating additive. The stepwise character of the combustion process evolution, being characterized by low- and high-temperature regimes, was revealed. The end-products were subjected to SEM, XRD and DTA/TG analyses.     

PostDock: A novel visualization tool for the analysis of molecular docking

“PostDock”, a new visualization tool for the analysis and comparison of molecular docking results is described. It processes a docking results database and displays an interactive pseudo-3D snapshot of multiple ligand docking poses such that their docking energies and docking poses are visually encoded for rapid assessment. The docking energies are represented by a transparency scale whereas the docking poses are encoded by a color scale. The applications of PostDock for ligand–protein docking and for a novel molecular design approach termed “reverse-docking” are presented.     

Embedded NMR sensors to monitor evaporable water loss caused by hydration and drying in Portland cement mortar

Providing adequate moisture content in cement-based materials is important during hydration of the cement paste to ensure proper development of their mechanical and durability properties. Subsequently, water is involved in the deterioration of concrete either as a pure liquid or by carrying aggressive species. This paper explores the use of small embedded NMR sensors to monitor evaporable water loss in Portland cement mortars. Results indicate that these sensors are effective in detecting loss of evaporable water due to hydration and drying. During drying, the mass loss is linearly proportional to the NMR signal loss. In addition, the amount of evaporable water detected with the sensor has a good correlation with the amount of evaporable water in a companion specimen tested in a traditional low field magnet by NMR and by gravimetric measurements.     

Modeling Municipal Solid Waste Collection Systems Using Derived Probability Distributions. II: Extensions and Applications

Three applications are used to demonstrate the utility of a derived probability model of curbside solid waste collection. First, the model is used to estimate the time required to collect waste from a route when the vehicle is constrained by time only. Second, the performance of a collection vehicle subjected to a capacity constraint is modeled. Finally, the model is used to compare the cost of using vehicles of different capacities. The results of the derived probability model compare well with the results of Monte Carlo simulations and with results reported in the literature. However, results can be obtained more directly with the derived probability model than from other methods.     

A user modeling approach for reasoning about interaction sensitive to bother and its application to hospital decision scenarios

In this paper, we present a framework for interacting with users that is sensitive to the cost of bother and then focus on its application to decision making in hospital emergency room scenarios. We begin with a model designed for reasoning about interaction in a single-agent single-user setting and then expand to the environment of multiagent systems. In this setting, agents consider both whether to ask other agents to perform decision making and at the same time whether to ask questions of these agents. With this fundamental research as a backdrop, we project the framework into the application of reasoning about which medical experts to interact with, sensitive to possible bother, during hospital decision scenarios, in order to deliver the best care for the patients that arrive. Due to the real-time nature of the application and the knowledge-intensive nature of the decisions, we propose new parameters to include in the reasoning about interaction and sketch their usefulness through a series of examples. We then include a set of experimental results confirming the value of our proposed approach for reasoning about interaction in hospital settings, through simulations of patient care in those environments. We conclude by pointing to future research to continue to extend the model for reasoning about interaction in multiagent environments for the setting of time-critical care in hospital settings.     

Effects of solvents and catalysts in liquefaction of pinewood sawdust for the production of bio-oils

Liquefaction of biomass with proper solvents and catalysts is a promising process to produce liquid biofuels and valuable chemicals. In this study, pinewood sawdust was liquefied in the presence of various supercritical solvents (carbon dioxide, water, acetone, and ethanol) and catalysts (alkali salts and acidic zeolites). The liquid, gas and solid products were analyzed using GC–MS, FT-IR, elemental analyzer, ¹H NMR, ¹³C NMR. The experimental results showed that both solvent and catalyst can significantly improve the liquefaction process by increasing the yield of liquid oil and suppressing the formation of solid residue. K₂CO₃ showed the best performance by doubling the yield of bio oil. Meanwhile, the maximum bio-oil yield (30.8 wt%) and the minimum solid residue yield (28.9 wt%) were obtained when ethanol was employed as the solvent. Solvents can also strongly affect the distribution of liquid products. 2,4,5,7-tetramethyl-phenanthrene and bis(2-ethylhexyl) phthalate were the premier compounds in liquid product as supercritical carbon dioxide is used as solvent while 2-methyl-naphthalene became the main composition when water is used as solvent.     

Perceptual control and layered protocols in interface design: I. Fundamental concepts

Perceptual Control Theory (PCT) is a general psychological theory based on the tenet, “All behaviour is the control of perception”. Layered Protocol Theory (LPT) can be seen as PCT applied to the special case of communication between cooperating partners, both controlling their own perceptions. PCT and LPT can be applied to the design and analysis of human×machine interfaces, although LPT may be more tractable in many cases. LPT is discussed in the context of the analysis and redesign of the interaction between a pilot and a Control Display Unit (CDU) in an operational helicopter.