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1.
In the present paper efforts have been made by the authors to study the changes in land use and land cover in Tripura using LANDSAT images of two different dates and to see how well data obtained help in the study of geographical phenomena with special reference to land use and land cover. The methodology for land-use mapping and limitations of LANDSAT data have been described in detail. The LANDSAT computer compatible tapes (CCTs) were analysed on the sophisticated interactive Multispectral Data Analysis System (MDAS) with the help of training sets of each category collected during field visits. Ninety per cent accuracy of these categories has been achieved when compared with existing data compiled on ground surveys by the working plan of the Division of Forest Department. The area of each land-use category was also calculated for monitoring land-use changes. 相似文献
2.
In an area like the Jharia coalfield (JCF), where extensive and rapid underground and opencast mining is going on continuously, land-use studies are of paramount importance. This paper discusses the remote sensing-GIS techniques used for identification of various land-use classes on satellite imagery and enhanced products and identification of time-sequential changes in land-use patterns. The various land-use classes, recognised from satellite image data and field surveys, are dense vegetation, sparse vegetation, fire, opencast mining (coal), overburden dump, subsidence and barren wasteland, settlement, transport network, river and water pond. A number of image processing operations have been carried out on remote sensing data for enhancing land-use patterns. It has been found that Landsat TM false colour composites (FCC) of bands 4, 3 and 2; FCC of bands 7, 5 and 3; FCC of bands 5, 4 and 2 and ratio images provide very useful information for land-use mapping. The normalised difference vegetation index (NDVI) images have been used for vegetation studies. Image characters of various land-use classes on black-and-white and enhanced colour products have been tabulated. Land-use maps of selected windows have been prepared and examples given. Time-sequential surface changes that have occurred in the JCF since 1975 and particularly between November 1990 to November 1994 have been investigated. For change detection analysis, data manipulation in several steps involving preprocessing, processing and colour display have been carried out. Land-use changes have been detected by (a) image differencing, (b) image ratioing, and (c) differencing of NDVI images. It is inferred from the remote sensing images that extensive mining, establishment of communication networks, expansion of settlements, decrease in the vegetation cover etc., have remodelled the face of the JCF. 相似文献
3.
During the last decade, the use of the normalized difference vegetation index (NDVI) for drought monitoring applications has drawn many criticisms, mainly because a number of drivers such as land-cover/land-use change, pest infestation, and flooding may depress the NDVI, further causing false drought identification. In this study, the impacts of land-cover change on the NDVI-derived satellite drought indicator, the vegetation condition index (VCI), are presented. It was found that the VCI is sensitive to changes in land cover, especially deforestation, the land cover changes from evergreen and deciduous forests to other land-cover classes. However, because the scale of land-cover changes was very small across the study area, only trivial drought alerts were observed in the VCI-based drought maps during non-drought years. Because drought is a large-scale climate event, it is reasonable to neglect these alerts. Besides, when the VCI was averaged to climate division scale, the results obtained through the VCI method were in good agreement with those acquired by the meteorological data-based drought indices such as the Palmer drought severity index and standardized precipitation index. 相似文献
4.
The objectives of this study are to quantify, based on remote sensing data, processes of land-cover change and to test a Markov-based model to generate short-term land-cover change projections in a region characterised by exceptionally high rates of change. The region of Lusitu, in the Southern Province of Zambia, has been a land-cover change 'hot spot' since the resettlement of 6000 people in the Lusitu area and the succession of several droughts. Land-cover changes were analysed on the basis of a temporal series of three multispectral SPOT images in three steps: (i) land-cover change detection was performed by combining the postclassification and image differencing techniques; (ii) the change detection results were examined in terms of proportion of land-cover classes, change trajectories and spatio-temporal patterns of change; (iii) the process of land-cover change was modelled by a Markov chain to predict land-cover distributions in the near future. The remote sensing approach allowed: (i) to quantify land-cover changes in terms of percentage of area affected and rates of change; (ii) to qualify the nature of changes in terms of impact on natural vegetation; (iii) to map the spatial pattern of land-cover change. 44% of the area has been affected by at least one change in land cover during the period 1986 to 1997. The average annual rate of land-cover change was 4.0%. Agricultural expansion was the dominant change process. Land-cover change trajectories highlighted the dynamic character of changes. The results obtained by applying a Markov chain for projecting future evolutions showed the continuing upward trend of bare soils and cultivated land, and the rapid downward trend of forests and other natural vegetation covers. 相似文献
5.
Remote sensing of land-cover change and landscape context of the National Parks: A case study of the Northeast Temperate Network 总被引:1,自引:0,他引:1
Yeqiao Wang Brian R. Mitchell Gregory Bonynge Gregory Shriver 《Remote sensing of environment》2009,113(7):1453-1461
National park units and protected areas face critical management challenges because of changing land-cover types and variability of landscape contexts within and adjacent the park boundaries. In this study we developed and implemented a multi-scale protocol for detecting and monitoring land-cover change in and adjacent to National Parks and ten segments of the Appalachian National Scenic Trail (AT) in the northeastern United States. We used Landsat imagery from 1970 to 2002 and recent ground-based photography to evaluate changes within park boundaries and within 0.5, 1, and 5 km buffers. The study concluded that all of the studied park units, except one segment of AT in Maine, experienced increases of urban land and declines of forest cover in the immediately adjacent areas and extended buffer zones. Over 30 years and across all parks and trail segments, urban land increased 172% and 181% within 0.5 and 1 km, respectively, of the park boundary or trail centerline. Over the same time period, forested area decreased by 5% and 6% within 0.5 and 1 km, respectively, of the park boundary or trail centerline, with more loss of forest near the parks (18%) than the trail segments (2%). This study provided baseline data demonstrating land-cover alteration over the past three decades and a foundation for a land-cover change and landscape context protocol suitable for monitoring future changes of National Parks and protected areas. 相似文献
6.
Weijia Li Le Yu Peng Gong Duole Feng Congcong Li 《International journal of remote sensing》2016,37(23):5632-5646
Land-cover mapping is an important research topic with broad applicability in the remote-sensing domain. Machine learning algorithms such as Maximum Likelihood Classifier (MLC), Support Vector Machine (SVM), Artificial Neural Network (ANN), and Random Forest (RF) have been playing an important role in this field for many years, although deep neural networks are experiencing a resurgence of interest. In this article, we demonstrate early efforts to apply deep learning-based classification methods to large-scale land-cover mapping. Based on the Stacked Autoencoder (SAE), one of the deep learning models, we built a classification framework for large-scale remote-sensing image processing. We adjusted and optimized the model parameters based on our test samples. We compared the performance of the SAE-based approach with traditional classification algorithms including RF, SVM, and ANN with multiple performance analytics. Results show that the SAE classifier trained with an entire set of African training samples achieves an overall classification accuracy of 78.99% when assessed by test samples collected independently of training samples, which is higher than the accuracies achieved by the other three classifiers (76.03%, 77.74%, and 77.86% of RF, SVM, and ANN, respectively) based on the same set of test samples. We also demonstrated the advantages of SAE in prediction time and land-cover mapping results in this study. 相似文献
7.
Jorge Conde Vieitez Alberto De La Torre Carcí a Marí a Teresa Vega Rodrí guez 《Behaviour & Information Technology》2001,20(3):213-223
The main objective of this study was to investigate the perception that workers have of technological change and its relation with psychological variables. The hypotheses investigated are based on the existence of the perception of technological change as a threat to job security and how this affects levels of anxiety, general stress and depression. The study was carried out in two departments of a car component factory: Engine Dept.-1 and Engine Dept.-2, outstanding for the different degrees to which technological innovation had been implemented. As procedure, a questionnaire made up of different scales was administered to a sample of 148 workers. Analysis of variance (ANOVA) and multivariate analysis of variance (MANOVA) was used as the fundamental statistical instrument. The results indicate that some variables (studies, department type, occupational category, technology type) significantly affect the perception that workers have of technology in relation to job security. The significant relation between technological perception and psychological well-being is also confirmed (F (4, 124) = 0.17, p = 0.00) although no significant differences were found in stress. In conclusion, the results indicate the importance of modifying workers' perceptions of technology in order to prevent problems of psychological well-being. 相似文献
8.
We have developed a characterization method based on measured surface profiles for room temperature seal-bonding using surface activated bonding (SAB) technique and investigated the quantitative influence of surface profiles on leakage. We used the model for the bonding between the perfect flat surface which is not deformed and the metal surface with sub-nanometer rms surface roughness based on AFM surface profiles. The leak rates of the model were calculated by the Monte–Carlo method. Specific critical contact ratio Psc gives the necessary contact ratio to disappear leak paths at a bonding interface. The Psc was also calculated by the simulation with a basic plastic deformation law. Surface profiles of as-sputtered Au and chemical mechanical polished Cu surfaces were used as the metal surfaces. Investigating the relationship between the contact ratio and the leak rate, it was found that leak rates decrease drastically at a contact ratio close to the Psc and leak rates decrease as the surface roughness decreases. Because of the drastic decrease of the leak rate, the vacuum sealing using SAB technique needs the contact ratio which is higher than Psc. We also found that in the case of the as-sputtered Au deposited by the same conditions (only the deposition time change), Psc has the tendency to decrease as the surface roughness decreases: if the rms roughness of the as-sputtered Au surface decreased from 1.5 to 0.5, the Psc decreased from 0.6 to 0.52. 相似文献
9.
生物膜作为生物体的一种基本组成单元,在各种生命活动中占据重要地位。生物膜的结构和功能的稳定性是其发挥一切生理功能的前提。本文以DPPC磷脂双分子层为生物膜模型,采用基于Martini力场的粗粒化模拟方法,考察了温度对DPPC磷脂双层膜结构、形态和功能的影响。结果表明,315 K为DPPC磷脂双层膜的相转变温度;温度升高,DPPC分子间隙增加,尾链发生折叠弯曲,引起脂均面积增大,厚度减小,流动性增加;DPPC双层膜中甘油酯基团组成的栅栏区为膜中分子排列最有序的区域,也是阻碍小分子透膜的主要屏障区。研究结果不仅有助于更好地阐释生物膜的结构形态和功能之间的关系,也有助于理解药物与膜的相互作用,指导临床用药。 相似文献
10.
The knowledge of nitrate fields at global or regional scales in the ocean is fundamental for the study of oceanic biogeochemical processes, particularly those linked to new primary production. The estimate of nitrate concentrations from space is generally based on empirical inverse relationships between sea surface temperature (SST) and nitrate concentrations. These relationships, however, are often highly variable spatially and temporally, and hardly applicable to large areas (i.e., larger than a few degrees in latitude). In this paper we propose a new approach specifically developed for areas influenced by upwelling processes. It relates the nitrate concentration to the difference between SST and the estimated temperature of the upwelled water (variable with latitude and season), δT, which is an indicator of the time elapsed since upwelling. This approach is tested for the Benguela upwelling system, and algorithms are developed using in situ data provided by the World Ocean Database 2005 of the NOAA-NESDIS-National Oceanographic Data Center. The results reveal a significant improvement compared to the NO3-SST relationships, and a single algorithm can be applied to the whole upwelling area (15 to 35°S). Further improvement is gained by coupling this approach with a method that derives sea surface nitrate concentrations from SST and surface chlorophyll a concentration using multiple regression analyses, as proposed by Goes et al. [Goes, Saino, Oaku, Jiang, (1999). Method for estimating sea surface nitrate concentrations from remotely sensed SST and chlorophyll a: A case study for the North Pacific Ocean using OCTS/ADEOS data. IEEE Transactions on Geoscience and Remote Sensing, 37, no. 3 II, 1633-1644]. 相似文献
11.
B. K. Bhattacharya N. Padmanabhan N. K. Patel J. S. Parihar 《International journal of remote sensing》2013,34(12):3239-3257
The shortwave and longwave radiation budget at land surfaces is largely dependent on two fundamental quantities, the albedo and the land surface temperature (LST). A time series (November 2005 to March 2006) of daily data from the Indian geostationary satellite Kalpana‐1 Very High Resolution Radiometer (K1VHRR) sensor in the visible (VIS), water vapour (WV) and thermal infrared (TIR) bands from noontime (0900 GMT) observations were processed to retrieve these quantities in clear skies for five winter months. Cloud detection was carried out using bispectral threshold tests (in both VIS and TIR bands) in a dekadal time series. Surface albedo was retrieved using a simple atmospheric transmission model. K1VHRR albedo was compared with Moderate Resolution Imaging Spectroradiometer (MODIS) AQUA noontime albedo over different land targets (agriculture, forest, desert, scrub and snow) that showed minimum differences over agriculture and forest. The comparison of spatial albedo over different landscapes yielded a root mean square deviation (RMSD) of 0.021 in VHRR albedo (9% of MODIS albedo). A mono‐window algorithm was implemented with a single TIR band to retrieve the LST. Its accuracy was also verified over different land targets by comparison with aggregated MODIS AQUA LST. The maximum RMSD was obtained over agriculture. Spatial comparison of VHRR and AQUA LSTs over homogeneous and heterogeneous landscape cutouts revealed an overall RMSD of 2.3 K. An improvement in the retrieval accuracy is expected to be achieved with atmospheric products from the sounder and split thermal bands in the imager of future INSAT 3D missions. 相似文献
12.
Y. Inoue Corresponding author A. Olioso W. Choi 《International journal of remote sensing》2013,34(10):1881-1892
This study investigated the potential of thermal remote sensing for estimating ecosystem surface CO2 flux. Ecosystem surface CO2 flux was measured by an eddy covariance method for more than 3 years, in conjunction with thermal and optical remote sensing measurements as well as micrometeorological, soil and plant measurements. The soil was Andisol (Hydric Hapludands), a humic volcanic ash soil, which is the major cultivated soil for upland crops in Japan. The soil surface CO2 flux under bare soil conditions was best correlated with the remotely sensed surface temperature, while air temperature was less well correlated and soil temperature and soil water content were poorly correlated. The relationship was well expressed by an exponential Q 10 function (r 2=0.66, RMSE=0.098). The value of Q 10 and the threshold temperature at which the CO2 flux approached zero were estimated to be 1.47 and 10.0°C, respectively. Results suggested that the soil surface temperature had the dominant effect on the microbial respiration as well as on the physical processes determining the CO2 gas transfer at the soil–atmosphere interface. Remotely sensed surface temperature will provide useful information for investigation of CO2 transfer processes near the soil surface, as well as for quantitative assessment of ecosystem surface CO2 flux. 相似文献
13.
14.
Many previous studies indicate that land-use/-cover change (LUCC) has effects on hydrological processes at the catchment level. The spatial pattern of LUCC (LUSP) may have different influences on hydrological processes. In this article, a mountainous catchment with different micro-topographic and micro-climatic types in the south-west of China was selected to study the LUSP and its impacts on annual sediment charge (ASC). Remotely sensed images from the Landsat Multi-Spectral Scanner (MSS), the Thematic Mapper (TM), the Enhanced Thematic Mapper Plus (ETM+) and the China–Brazil Earth Resource Satellite (CBERS) were used to retrieve land-use/-cover conditions for the past three decades. The multispectral operational method for TM/ETM+?and spectral threshold methods for MSS and CBERS were employed to retrieve the topographic shadows. LUCC was analysed in different topographic areas, proximities to streams and micro-climate areas. The impacts of LUCC on ASC were then calculated and analysed by the weights of different land-use/-cover types in different spatial zones. The results showed that LUCC makes significant contributions to changes in ASC, especially in areas with a slope of 6°–35°, higher elevation areas (>1650 m ASL) and areas close to rivers (buffering distance less than 3000 m). In these areas, forest and grassland experienced greater changes than other areas, which indicate that the changes in ASC may be associated with the reforestation efforts since 1989. 相似文献
15.
The author describe their incorporation of IDDQ testing into the design of the PA-7100LC PA-RISC microprocessor. They also discuss design guidelines, measurement techniques, results after fabrication and volume production, and suggested improvement. Their 900,000-transistor custom design supports IDDQ testing to ensure high quality without compromising 100-MHz-plus performance 相似文献
16.
R. N. Silva P. O. Shirley J. M. Lemos A. C. Gonalves 《Control Engineering Practice》2000,8(12):0613011-1415
This paper describes the application of the MUSMAR predictive adaptive controller to the regulation of super heated steam temperature in a commercial boiler. The boiler considered produces 150 t/h of steam at maximum load, used both for electric energy production in a turbine and industrial use. The combination of predictive and adaptive techniques, relying on multiple models redundantly estimated, allows a continuous adjustment of the controller tuning for tracking plant dynamics variations. This paper describes experiments actually performed on the plant with adaptive predictive control, in particular in the presence of load changes. A reduction of steam temperature fluctuations with respect to an optimized cascade of PI controllers is observed. 相似文献
17.
磷石膏加热时间的不确定性问题制约了磷石膏的研究与利用,本文对磷石膏的处理采用微波加热的方法,并通过MATLAB曲线拟合技术对实验数据进行拟合,得到磷石膏在微波加热期间和冷却过程中时间与磷石膏温度的关系曲线,同时得到曲线方程表达式。磷石膏时间与温度曲线出现了若干基点,本文分析了其变化的原因,解决了磷石膏温度及加热时间确定性问题。结果表明在微波加热初期,磷石膏温度与时间呈分段线性关系,这主要取决于磷石膏的介电常数;而在冷却过程中,磷石膏温度与时间呈二次线性关系,这主要取决于磷石膏的导热系数。利用所得函数可以得出磷石膏加热所需时间,同时利用所得加热时间也能推算磷石膏加热最高温度。 相似文献
18.
T. Diana L v. A. de Macedo‐Soares Ph.D. Paulo Jacinto Pastor‐Braga B.Sc. 《Information Technology for Development》2013,19(4):453-485
Abstract This article gives an account of the results of a case study undertaken at a pioneer and particularly prominent firm in the Brazilian computer industry: COBRA — Computadores e Sistemas Brasileiros SA. The study is part of a research project1 whose main goal is the identification of viable organizational and technological options that could enhance the performance of firms in the Brazilian electro‐electronics industry. Among the more important findings, it was observed that the firm has the potential to evolve to a more flexible structure, in keeping with the new requirements of the probable future market scenarios within its sector. Everything indicated, however, that the main constraining factors for bringing about such a structure were connected with the firm's culture and beliefs and with the indirect influence of the National Policy of Information Technology upon these. An hypothesis was put forward for an organizational model, and the necessary supportive computerized technology, which could be particularly appropriate in view of the impending deregulation, of the Brazilian computer industry. Also, in the scope of the current discussion on the restructuring of this industry in terms of a greater concentration, an alternative to the prevailing school of thought was proposed, and for whose success the organizational model at issue purports to be particularly relevant. 相似文献
19.
《International journal of remote sensing》2012,33(6):2081-2097
ABSTRACTModerate Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) data of MODIS 11A2 and Normalized Difference Vegetation Index (NDVI) products of MODIS 13Q1 were used to analyse the spatial and temporal changes of LST and its relationship with vegetation from 2001 to 2015 in the subtropical region of Fujian Province, China. The LST and NDVI products were reconstructed by Savitzky–Golay (S-G) filtering for abnormal values or missing data due to the influence of cloud contamination. The LST of Fujian decreases from its southeast coast to its northwest mountain area, and the annual average highest LST is greater than 30°C while the lowest LST is about 15°C. In the past 15 years, the average LST in Fujian has declined gradually due to an increase in fractional vegetation coverage (FVC), but the highest LST increased from 30.95°C to 33.05°C across south-east coastal zone cities due to rapid urbanization. From 2001 to 2015, the LST of Fujian Province trended slightly downward; the LST area, however, significantly decreased by 18.85% of the total area of the province and was twice that of the (significant) increase in LST. The changing trend distributions of LST are opposite to those of FVC in general, but LST decreases to greater extent as FVC increases when FVC is above 0.2 – every 10% increase in FVC is accompanied by about a 1.1°C decrease in LST. 相似文献
20.
Land surface temperature (LST) is a key parameter in numerous environmental studies. Surface heterogeneity induces uncertainty in estimating subpixel temperature. To take an advantage of simultaneous, multi-resolution observations at coincident nadirs by the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) and the MODerate-resolution Imaging Spectroradiometer (MODIS), LST products from the two sensors were examined for a portion of suburb area in Beijing, China. We selected Soil-Adjusted Vegetation Index (SAVI), Normalized Multi-band Drought Index (NMDI), Normalized Difference Built-up Index (NDBI) and Normalized Difference Water Index (NDWI) as representative remote sensing indices for four land cover types (vegetation, bare soil, impervious and water area), respectively. By using support vector machines, the overall classification accuracy of the four land cover types with inputs of the four remote sensing indices, extracted from ASTER visible near infrared (VNIR) bands and shortwave infrared (SWIR) bands, reached 97.66%, and Kappa coefficient was 0.9632. In order to lower the subpixel temperature estimation error caused by re-sampling of remote sensing data, a disaggregation method for subpixel temperature using the remote sensing endmember index based technique (DisEMI) was established in this study. Firstly, the area ratios and statistical information of endmember remote sensing indices were calculated from ASTER VNIR/SWIR data at 990 m and 90 m resolutions, respectively. Secondly, the relationship between the 990 m resolution MODIS LST and the corresponding input parameters (area ratios and endmember indices at the 990 m resolution) was trained by a genetic algorithm and self-organizing feature map artificial neural network (GA-SOFM-ANN). Finally, the trained models were employed to estimate the 90 m resolution subpixel temperature with inputs of area ratios and endmember indices at the 90 m resolution. ASTER LST product was used for verifying the estimated subpixel temperature, and the verified results indicate that the estimated temperature distribution was basically consistent with that of ASTER LST product. A better agreement was found between temperatures derived by our proposed method (DisEMI) and the ASTER 90 m data (R2 = 0.709 and RMSE = 2.702 K). 相似文献