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991.
The overarching goal of this study was to develop a comprehensive methodology for mapping natural and human‐made wetlands using fine resolution Landsat enhanced thematic mapper plus (ETM+), space shuttle radar topographic mission digital elevation model (SRTM DEM) data and secondary data. First, automated methods were investigated in order to rapidly delineate wetlands; this involved using: (a) algorithms on SRTM DEM data, (b) thresholds of SRTM‐derived slopes, (c) thresholds of ETM+ spectral indices and wavebands and (d) automated classification techniques using ETM+ data. These algorithms and thresholds using SRTM DEM data either over‐estimated or under‐estimated stream densities (S d) and stream frequencies (S f), often generating spurious (non‐existent) streams and/or, at many times, providing glaring inconsistencies in the precise physical location of the streams. The best of the ETM+‐derived indices and wavebands either had low overall mapping accuracies and/or high levels of errors of omissions and/or errors of commissions.

Second, given the failure of automated approaches, semi‐automated approaches were investigated; this involved the: (a) enhancement of images through ratios to highlight wetlands from non‐wetlands, (b) display of enhanced images in red, green, blue (RGB) false colour composites (FCCs) to highlight wetland boundaries, (c) digitizing the enhanced and displayed images to delineate wetlands from non‐wetlands and (d) classification of the delineated wetland areas into various wetland classes. The best FCC RGB displays of ETM+ bands for separating wetlands from other land units were: (a) ETM+4/ETM+7, ETM+4/ETM+3, ETM+4/ETM+2, (b) ETM+4, ETM+3, ETM+5 and (c) ETM+3, ETM+2, ETM+1. In addition, the SRTM slope threshold of less than 1% was very useful in delineating higher‐order wetland boundaries. The wetlands were delineated using the semi‐automated methods with an accuracy of 96% as determined using field‐plot data.

The methodology was evaluated for the Ruhuna river basin in Sri Lanka, which has a diverse landscape ranging from sea shore to hilly areas, low to very steep slopes (0° to 50°), arid to semi‐arid zones and rain fed to irrigated lands. Twenty‐four per cent (145 733 ha) of the total basin area was wetlands as a result of a high proportion of human‐made irrigated areas, mainly under rice cropping. The wetland classes consisted of irrigated areas, lagoons, mangroves, natural vegetation, permanent marshes, salt pans, lagoons, seasonal wetlands and water bodies. The overall accuracies of wetland classes varied between 87% and 94% (K hat = 0.83 to 0.92) with errors of omission less than 13% and errors of commission less than 1%.  相似文献   
992.
In this paper, we propose a framework to facilitate handheld device-based PointMe interaction with annotated media content, where the user points his/her handheld device to the media presentation screen in order to access services/information from the annotated media. Each annotation is encoded into customized learning object metadata (LOM) format that provides access point for available information about a specific media on the screen. By incorporating a fusion of infra-red (IR) motion points and accelerometer data of the handheld device, the system determines the learner’s PointMe location on the media screen. By using the pointed location spatial geometrical query is performed over the displayed annotated media in order to deliver learner’s level-specific interactive learning content to the user’s handheld device. The level customization is achieved by incorporating learner’s age, progress, etc., parameters in the media content delivery process. We design intuitive learning scenarios by leveraging the PointMe interaction scheme, where learners are challenged to answer quiz questions in learning-based games. This real-world interaction technique with the annotated media and seamless virtual learning information acquisition process makes the system transparent to young learners and encourage them to engage and concentrate on their learning activities. We develop a prototype and perform experiments in a technology-augmented learning space to show the suitability of the proposed approach.  相似文献   
993.
Bulk micromachining in Si (110) wafer is an essential process for fabricating vertical microstructures by wet chemical etching. We compared the anisotropic etching properties of potassium hydroxide (KOH), tetra-methyl ammonium hydroxide (TMAH) and ethylene di-amine pyro-catechol (EDP) solutions. A series of etching experiments have been carried out using different etchant concentration and temperatures. Etching at elevated temperatures was found to improve the surface quality as well as shorten the etching time in all the etchants. At 120°C, we get a smooth surface (Ra?=?21.2?nm) with an etching rate 12.2???m/min in 40wt% KOH solution. At 125°C, EDP solution (88wt%) was found to produce smoothest surface (Ra?=?9.4?nm) with an etch rate of 1.8???m/min. In TMAH solution (25wt%), the best surface roughness was found to be 35.6?nm (Ra) at 90°C with an etch rate of 1.18???m/min. The activation energy and pre-exponential factor in Arrhenius relation are also estimated from the corresponding etch rate data.  相似文献   
994.
Dutta  Shankar  Imran  Md  Kumar  P.  Pal  R.  Datta  P.  Chatterjee  R. 《Microsystem Technologies》2011,17(10):1621-1628

Bulk micromachining in Si (110) wafer is an essential process for fabricating vertical microstructures by wet chemical etching. We compared the anisotropic etching properties of potassium hydroxide (KOH), tetra-methyl ammonium hydroxide (TMAH) and ethylene di-amine pyro-catechol (EDP) solutions. A series of etching experiments have been carried out using different etchant concentration and temperatures. Etching at elevated temperatures was found to improve the surface quality as well as shorten the etching time in all the etchants. At 120°C, we get a smooth surface (Ra = 21.2 nm) with an etching rate 12.2 μm/min in 40wt% KOH solution. At 125°C, EDP solution (88wt%) was found to produce smoothest surface (Ra = 9.4 nm) with an etch rate of 1.8 μm/min. In TMAH solution (25wt%), the best surface roughness was found to be 35.6 nm (Ra) at 90°C with an etch rate of 1.18 μm/min. The activation energy and pre-exponential factor in Arrhenius relation are also estimated from the corresponding etch rate data.

  相似文献   
995.
Inherent complexity and uncertainty in a business environment necessitate the participation of many experts in multi criteria decision making. However, participation of many experts makes the conflict aggregation process difficult. To handle this difficulty, we propose two algorithms namely possibility measure and averaging conflict aggregation. In possibility measure, we integrate the possibility theory of fuzzy logic with a maximal containment method that is designed based on the decision problem. Possibility measure algorithm for ME-MCDM involves computationally expensive multiple information processing steps. Therefore to test and compare this algorithm, averaging conflict aggregation algorithm is proposed that requires fewer mathematical information processing steps. Based on the proposed algorithms, a decision support system (DSS) is developed. We present a case study of supplier evaluation to compare both of the proposed algorithms with the help of developed DSS.  相似文献   
996.
997.
Manufacturing organizations are constantly striving to develop more effective and flexible means for managing challenges due to globalization and increasing customer expectations. This has led to increased efforts by the business community to research and implement the Toyota Production System, or lean manufacturing, to address these challenges. These efforts have resulted in numerous publications on lean manufacturing, including research reports, scholarly articles, and trade magazine articles. However, the existing body of knowledge on lean manufacturing is disperse and diverse in nature with respect to the application and implementation of lean tools and practices, making it difficult for researchers and practitioners to gain a real grasp of this topic. In this article, we have comprehensively organized the existing work on implementation of lean manufacturing in a more structured way, enabling engineering management practitioners to more easily identify knowledge and best practices and enabling researchers to identify gaps in the extant literature. Lastly, drawing from the organizational science literature, this article also provides important insights on lean manufacturing from the perspective of organizational learning, innovation, and \culture.  相似文献   
998.
999.
Polypyrrole–silver (PPy–Ag) nanocomposites with various silver contents have been synthesized via a kinetically favorable one-step chemical oxidative polymerization process. The oxidant, ammonium persulfate, was used to oxidize pyrrole monomer for growing chains of PPy. And AgNO3 was used as a precursor for metallic silver nanoparticles. The detailed characterization techniques, UV–Vis–NIR, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction spectroscopy, field-emission scanning electron microscopy, and transmission electron microscopy (TEM), have been used to reveal electronic environment, structure, and morphology of composites as well as as-synthesized PPy. The synthesis environment prior to polymerization has also been investigated by absorption spectroscopy. The TEM images of PPy–Ag nanocomposites reveal that silver nanoparticles are deeply embedded into the polymer matrix in addition to surface adsorption. It is observed that the size distribution of inorganic nanoparticles (ca. 4–10 nm, depending on the metal ion concentrations) as well as structural morphology is altered by the initial concentrations of silver ions.  相似文献   
1000.
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