Feasibility of neural network approach in spectral mixture analysis of reflectance spectra

In the present work, we perform spectral mixture analysis using Chi‐square minimization (χ² minimization) procedure and test the feasibility of applying an inverse technique, neural network (NN) approach, for the spectral unmixing. The training of NN is carried out using the Levenberg–Marquardt algorithm (LM) with the initial weights for training being chosen randomly. The experiments are performed in the laboratory by mixing young, matured and dead leaves of a sequoia tree in various proportions and reflectance spectra of these mixtures are recorded. The proportions are chosen to model a few near‐real situations like different kinds of vegetation in a forest (by mixing young leaves and matured leaves) and trees damaged in a forest fire or affected by certain virus (by mixing matured and dead leaves) and a combination of all these (by mixing young, matured and dead leaves). The spectral mixture analysis employing χ² minimization and the inverse procedure utilizing NN with two hidden layers yielded consistent results in accordance with the proportion of each kind of leaf.     

Model-driven approach to enterprise interoperability at the technical service level

Enterprise Interoperability is the ability of enterprises to interoperate in order to achieve their business goals. Although the purpose of enterprise interoperability is determined at the business level, the use of technical (IT) services to support business services implies that interoperability solutions at both the business and technical level should be aligned. This paper introduces and demonstrates the suitability of an approach based on model transformations to automate enterprise interoperability. We start by considering that a set of enterprises are willing to interoperate in the context of their individual goals. The interactions necessary for their cooperation are then properly captured in terms of a so-called choreography. Our approach allows a choreography to be mapped and transformed to an orchestration, which defines the operation of the actual technical services of the interoperating enterprises. The paper discusses the technical challenges of implementing the transformation, and illustrates our approach with two application scenarios.     

Provitamin‐A and xanthophyll carotenoids in vegetables and food grains of nutritional and medicinal importance

This study reports carotenoid composition of vegetables (n = 56), cereals (n = 12), pulses and legumes (n = 12), analysed by HPLC. It was hypothesised that food grains, like vegetables may be good sources of carotenoids. Amongst vegetables, higher level (mg/100 g dry weight) of lutein (210–419) was detected in green/red/capsicum and yellow zucchini, whilst zeaxanthin was dominant in kenaf (4.59). β‐Carotene (mg/100 g dry weight) was higher in green capsicum and kenaf (48,159) whilst carrot, ivy gourd and green capsicum contain α‐carotene (22–110). Amongst food grains, chickpea, split red gram and flaxseed contain higher levels (μg/100 g dry weight) of lutein (185–200) whilst zeaxanthin level was highest in puffed chickpea (1.8). Red unpolished parboiled rice was richest (μg/100 g dry weight) in β‐carotene (67.6) whilst whole black gram contained higher levels of α‐carotene (52.7). Thus, results indicate that chickpea and red unpolished parboiled rice are good sources of carotenoids. These carotenoid‐rich vegetables and grains may be exploited to meet the lutein and β‐carotene requirement.     

Properties of solids under high pressure—An electronic band structure approach

The predicting capability of various parameters related to solids by performing their high pressure electronic band structures is discussed in detail. The studies on ground state crystal structure, magnetic structure and magnetic phase transitions under pressures,s-d electron transitions, bulk modulus, Debye temperature, elastic constants, insulator to metal transitions and the phenomenon of pressure induced superconductivity will be discussed with examples. Especially the method of calculating the Debye temperature for a large number of ternary charlcopyrite systems using their recently evaluated band structure will be presented. The limitations of the band theory when used with the local density approximation with respect to the determination of band gaps and magnetic properties will also be discussed.     

Mathematical Description of Experimentally Determined Charge Distributions of a Unipolar Diffusion Charger

The charge distributions of an improved opposed flow unipolar diffusion charger were measured using a tandem differential mobility analyzer (DMA) set up in a size range of approximately 20–400 nm. The charger is intended to be used in a portable aerosol sizer to measure particle size distributions. The determined charge distributions were represented by lognormal distributions, and a set of equations and coefficients was developed to calculate the charge distributions. These equations can be easily implemented in software for size distribution measurements. The agreement between the mathematically derived and measured charge distributions is very good, with regression coefficients R ² > 0.96. The investigations showed that approximately 55% of 20-nm particles remain uncharged, while up to 25 elementary charges need to be considered for multiple charge correction of 400-nm particles. Comparison with the Fuchs theory delivered satisfying agreement with the measured average charge levels, but charge distributions cannot be described by the Fuchs theory, likely caused by the charger geometry.

Copyright 2012 American Association for Aerosol Research     

西九文化区

正OMA发展西九文化区,必须面对一项挑战:将一个盛载政府极大抱负,以及持分者多元利益的超大型多用途项目,转化成一个既有趣又严肃、既有规划又允许即兴、既中国化又国际化的文化区。这个文化区规模庞大,但不失亲密融洽的感觉;富地标性,但十分谦和;容易理解,却能带来惊喜。为避免造成过分冲击,OMA采纳了一种每个香港市民都熟悉的建筑类型作为方案的发展     

Colour centres and thermally stimulated luminescence of Na2ZnCl4

Thermally stimulated luminescence (TSL) of Na₂ZnCl₄ single crystals showed three glow peaks having their peak maxima at 343, 425 and 475 K. Optical absorption (OA) data of unirradiated samples revealed an absorption band at 272 nm while X-irradiation caused additional bands at 462 and 723 nm. Growth and room temperature annealing studies of TSL and OA supported the idea of attribution of 425 K glow peak and 462 nm absorption band to F-centres. The 272 nm OA band is due to Zn²⁺ centres whereas the 723 nm absorption band and 475 K glow peak have been assigned to Zn⁺ centres.     

Case study of safe lowering of an in service gas pipeline

This paper describes an experimental investigation carried out involving instrumentation, measurement and monitoring of stresses in a large diameter gas pipeline during its lowering operations. It also highlights the ingenious techniques developed and adopted to overcome the difficulties pertaining to long leadwires, measurement of existing strains on the curved surface of a pipeline and protection of strain gauge installations. These novel methods were used to ensure smooth and proper functioning of strain gauge instrumentation even under the severe field conditions at site for more than two weeks, till the lowering operations and pipeline monitoring was successfully completed.