IPv4/IPv6转换网关的设计与实现

详细介绍了IPv4IPv6转换网关的设计与实现过程;首先介绍转换网关的工作流程,其次介绍地址转换和协议转换设计,最后分析了DNS ALG设计。     

基于ArcGIS软件的数据扫描矢量化与数据转换

扫描矢量化是对各种类型的数字工作底图如纸基地图等进行矢量化处理,扫描矢量化工作是数据处理、数据转换的基础,本文通过南方Cass软件实现了地图扫描矢量化工作;数据转换就是把不同格式的空间数据转换成所用地理信息系统平台使用的格式,是对数据进一步处理与分析的前提。本实验通过应用ArcGIS软件实现了数据的转换,为避免直接转换存在的问题,本实验采用的方法是在ARCMAP中读入转换后的数据,然后将各类要素分别筛选出,再生成新的要素层。     

基于加密狗的坐标转换参数加密方法研究与实现

不同坐标系成果之间的转换是测量工作中必不可少的环节。基于转换参数保密的需求,如何确保转换参数不被泄密是坐标转换过程中需要解决的问题。本文基于新一代加密狗的特点,提出利用加密狗对转换参数加密和存储,并将坐标转换或混淆的代码移植到加密狗内,实现了省级海量参数的加密、管理和调用,有效杜绝了转换参数和坐标转换过程的泄密,大大提高了保密强度。     

基于Visual Basic的水文数据格式的自动转换

结合推进水利部门信息化的工作需要,本文利用当前的快速应用程序开发工具VisualBasic实现了水文水位数据传输系统的数据后处理—自动格式转换,大大提高了部门工作效率,让计算机程序顶替了原来的手工操作,对于水利领域乃至其他行业中的数据格式转换工作具有一定的参考价值。     

具有信令转换功能的有线无线自动转接机

本文介绍一种具有信令转换功能的有线无线自动转换接收机,并对其电路结构、软件编程、特别是信令转换的工作原理进行了较详细的分析。     

基于ATM和Internet的视频点播系统的设计与实现

本文探讨了基于ATM和Internet传输视频点播业务系统的基本原理和实验实现。该系统由业务代理器和交互工作单元组成,业务代理器控制系统内的资源分配及业务指南,交互工作单元在代理器的控制下实现各种功能转换,包括：数据流传输协议转换、比特率控制、业务网关转换、业务量监测。     

IPv4和IPv6协议转换的应用研究

本文简要介绍了系统工作流程和TCP／UDP协议的转换,重点阐述了IPv4-IPv6协议转换中的算法和流程。     

基于模型驱动架构的工作流管理系统开发研究

针对企业在导入或转换新的工作流平台时重新建模的问题,提出基于MDA的工作流管理系统开发架构.此架构中工作流程的建模分成两个阶段,首先设计了工作流程的PIM元模型并进行PIM建模,然后将PIM转换成PSM模型,最后再由PSM自动产生流程定义文件,这样在转移工作流程平台时,流程的PIM模型可以保留并以模型转换技术对应至新平台的PSM模型.给出了由PIM元模型转换为WfMC PSM模型的程序以及由WfMC PSM模型转换为XPDL流程定义的程序,并以电子订单工作流程为例进行了验证.此开发架构降低了流程平台转移时的成本与复杂度,提高了工作流程模型的可重用性.     

RS232-IIC通信转换卡的设计与实现

设计了一个结构简单、使用方便的RS232串行口与IIC总线通信转换卡,详细介绍了该转换卡的工作原理和实现方法,即通过软硬件相结合实现电平标准和通信协议的转换,从而完成两者之间的信息传输。     

一种基于MEMS的同位素微电池的新型结构设计与仿真

针对传统同位素微电池的倒三角直槽型或倒金字塔型能量转换结构表面积较小和工作状态不稳定的缺陷.设计了一种垂直侧壁方孔阵列型的能量转换结构,增大了其表面积;并引入电镀这一新型的接触方式,改善了同类传统微电池的工作稳定性.建立了同位素微电池的电流计算公式.基于这种新结构对电池性能仿真得到了能量转换结构的最佳掺杂浓度,结果表明该结构与传统的能量转换结构相比,具有较低的掺杂浓度,较高的开路电压,输出电流和输出功率.     

基于异构服务的水资源遥感监测平台设计与实现

遥感监测是获取水资源信息的重要手段,但是水资源遥感监测数据的多源化及算法和服务异构化的特点,使得数据及应用共享不足等问题日渐突出.为解决数据和算法的多源集成管理问题,研究建立基于异构服务的水资源遥感监测平台,以充分利用各类水资源数据及服务.主要通过KVM实现底层资源虚拟化,为数据体量及异构等问题提供解决思路;通过分布式...     

Quantitative monitoring of inland water using remote sensing of the upper reaches of the Huangpu River,China

In this paper, a quantitative framework using common and readily available remote sensing data, including ground hyperspectral data, multispectral remote sensing images and a regular in situ water quality monitoring programme, is proposed to monitor inland water quality. The entire framework has three steps: (1) collecting and processing basic data, including remote sensing data and water quality data; (2) examining the relationships between water quality parameters and water reflectance from both remote sensing images and in situ measurement data. According to their relationships with ground hyperspectral reflectance, the water quality parameters are classified into three categories, and the corresponding monitoring models using remote sensing data are presented for these three categories; and (3) analysing the spatial distribution by using water quality concentration maps generated with the monitoring models. The upper reaches of the Huangpu River were chosen as our study area to test this framework. The results show that the concentration maps inverted by the proposed models are in accordance with the actual situation. Therefore, we can conclude that the proposed framework for quantifying water quality based on multisource remote sensing data and regular in situ measurement data is an effective and economic tool for the rapid detection of changes in inland water quality and subsequent management.     

Realistically rendering polluted water

Polluted water is very common in our world. Vividly rendering polluted water can bring people real, different, and fancy feelings. Especially in under water imagery, taking polluted water into consideration will produce more plausible results. Polluted water consists of many kinds of pollutants, which interact with light differently and make water look turbid. The optical properties of polluted water change with the concentrations of pollutants significantly. In this paper, we provide a method to obtain the optical properties of polluted water, which makes a bio-optical model for polluted water and connects the optical parameters with water quality data, i.e., the concentrations of pollutants. Our method can estimate the optical properties of polluted water regardless of the kinds and the concentrations of pollutants in water. Polluted water is inhomogeneous and has multiple scattering effects. We use volumetric photon mapping to render it and provide a 3D weight-varying radiance estimate method for the photon mapping. This radiance estimate method can compute high-frequency effects easily, which can show more details of the pollution process. Experiments demonstrate that our approach can generate polluted water effects unachievable by standard rendering methods.     

Comparison and improvement of methods for identifying waterbodies in remotely sensed imagery

This article first examines three existing methods of delineating open water features, i.e. the normalized difference water index (NDWI), the modified normalized difference water index (MNDWI) and a method combining the near-infrared (NIR) band and the maximum likelihood classification. We then propose two new methods for the fast extraction of water features in remotely sensed imagery. Our first method is a pixel-based procedure that utilizes indices and band values. Based on their characteristic spectral reflectance curves, waterbodies are grouped into three types – clear, green and turbid. We found that the MNDWI is best suited for identifying clear water. Green water has its maximum reflectance in Landsat Thematic Mapper (TM) band 4 (NIR band), whereas turbid water has its maximum reflectance in TM band 5 (mid-infrared band). Our second method integrates our pixel-based classification with object-based image segmentation. Two Landsat scenes in Shaanxi Province, China, were used as the primary data source. Digital elevation models (DEMs) and their derived slope maps were used as ancillary information. To evaluate the performance of the proposed methods, extraction results of the three existing methods and our two new methods were compared and assessed. A manual interpretation was made and used as reference data. Results suggest that our methods, which consider the diversity of waterbodies, achieved better accuracy. Our pixel-based method achieved a producer's accuracy of 92%, user's accuracy of 90% and kappa statistics of 0.91. Our integrated method produced a higher producer's accuracy (95%), but a lower user's accuracy (72%) and kappa statistics (0.72), compared with the pixel-based method. The advantages and limitations of the proposed methods are discussed.     

Mapping groundwater salinity using IRS-1B LISS II data and GIS techniques

A procedure is presented for ground water exploration in terms of depth and quality in an alluvial terrain with shallow groundwater occurrence. The study area forms a part of the marginal Gangetic terrain with a clay-sand sequence. Variation in groundwater quality has been mapped in earlier research on the basis of field sampling and chemical analysis of groundwater. In the present study, a scheme of image processing and GIS techniques using false colour composites, vegetation indices, density slicing, image registration, overlaying, and supervised classification has been applied on IRS-1B LISS II data. Various zones established within the terrain based on our research are in conformity with ground water salinity and depth contours.     

Feedback mechanisms between water availability and water use in a semi-arid river basin: A spatially explicit multi-agent simulation approach

Understanding the processes responsible for the distribution of water availability over space and time is of great importance to spatial planning in a semi-arid river basin. In this study the usefulness of a multi-agent simulation (MAS) approach for representing these processes is discussed. A MAS model has been developed to represent local water use of farmers that both respond to and modify the spatial and temporal distribution of water resources in a river basin. The MAS approach is tested for the Jaguaribe basin in semi-arid Northeast Brazil. Model validity and required data for representing system dynamics are discussed. For the Jaguaribe basin both positive and negative correlations between water availability and water use have been encountered. It was found that increasing wet season water use in times of drought amplify water stress in the following dry season. It is concluded that with our approach it is possible to validly represent spatial-temporal variability of water availability that is influenced by water use and vice versa.     

A localization method for stagnant water in city road traffic image

Stagnant water on roads has always been a major cause of traffic jams and accidents. Traditional urban waterlogging monitoring and warning system is mainly based on a large amount of historical data and predictive network, which has low accuracy and weak generalization ability. Considering the deep neural network algorithms have demonstrated strong capabilities in computer vision tasks such as object detection, we aim to apply them to road stagnant water detection. In this paper, a novel automatic stagnant water localization method under weak supervision based on visual image is proposed. First, the template matching method is applied to extract road information from the traffic image. Then, due to the complexity of data annotation, we locate stagnant water in image based on Class Activation Maps (CAM) mechanism, which is a weakly supervised method. The detection model consists of the ResNet-18 and the Grad-CAM++ mechanism. Finally, based on the heat map and template, we set a suitable threshold to segment stagnant water area in image. In the experiments, the precision and recall for road stagnant water classification by the proposed model are 99.39% and 99.60%, while the Intersection over Union (IoU) for stagnant water area segmentation is up to 63%. These show that our method is effective for road stagnant water localization.

     

Underwater polarization‐based single pixel imaging

This paper extends single pixel imaging (SPI) to underwater scenario. Backscattering, which is a limiting factor for underwater imaging, is analyzed for the SPI, and the forward model of SPI under backscattering is formulated. Inspired by the polarization‐based descattering technique, we propose the two cross‐polarization SPI detection scheme to eliminate the backscattering light. The descattered image is reconstructed from the cross‐polarization data. Experimentally, we construct the underwater polarization‐based single‐pixel imaging system. And we test our scheme under different turbidity water. It is shown in experiments that our method can provide a clear image at turbid water of 32FTU, where the classical SPI has been severely contaminated by the backscattering, even under the best the polarization state.     

Least cost distance analysis for spatial interpolation

Spatial interpolation allows creation of continuous raster surfaces from a subsample of point-based measurements. Most interpolation approaches use Euclidean distance measurements between data points to generate predictions of values at unknown locations. However, there are many spatially distributed data sets that are not properly represented by Euclidean distances and require distance measures which represent their complex geographic connectivity. The problem of defining non-Euclidean distances between data points has been solved using the network-based solutions, but such techniques have historically relied on a network of connected line segments to determine point-to-point distances. While these vector-based solutions are computationally efficient, they cannot model more complex 2- and 3-dimensional systems of connectivity. Here, we use least-cost-path analyses to define distances between sampled points; a solution that allows for arbitrarily complex systems of connectivity to be interpolated. We used least-cost path distances in conjunction with the inverse distance weighting interpolation for a proof-of-concept interpolation of water temperature data in a complex deltaic river system. We compare our technique to Euclidean distance interpolation, and demonstrate that our technique, which follows connectivity rules, yields are more realistic interpolation of water temperature.