自适应空间信息移动服务

空间信息移动服务系统是空间信息系统继由传统PC计算环境向有线Web分布式计算环境扩展后，向移动计算环境的新发展。文中在分析移动计算环境概念和特点的基础上，讨论了空间信息移动服务的若干特点及关键技术，研究了自适应空间信息移动服务方案。     

元启发式搜索策略在构造模糊分类系统中的应用

论述了使用模拟退火元启发式搜索策略构造模糊分类系统的过程,目的是利用模拟退火原理研制一种精确的模糊分类器,改善与分类问题有关的搜索空间探索与发掘的性能,找到模糊if-then规则的优化集。算法可以从输入数据集中抽取精确的模糊分类规则,并在若干不同预定义类中将其应用于对新数据实例的分类。     

数据共享与电子政务

近年来,中国的电子政务建设在政府政策导向和市场需求的推动下,取得了一定的成就,但是随之也沉淀了一些问题,其中信息资源无法得到有效的利用和共享的问题尤其突出。最近出台的《行政许可法》为电子政务建设的顺利发展扫除了法律上的主要障碍。3S的应用越来越广泛,差不多涉及到国民经济的各个领域;随着国家的经济发展和现代化的城市建设,3S技术还将在城市信息系统、特别城市智能交通(ITS)中发挥越来越大的作用,GIS成为政府业务的必需品的局面正在形成。下一代网络计算技术将开辟信息服务的新时代,GIS技术将在国家的信息化建设中发挥更大作用。     

High-performance three-horizon composition algorithm for large-scale terrains

This work presents a high-performance algorithm to compute the horizon in very large high-resolution DEMs. We used Stewart's algorithm as the core of our implementation and considered that the horizon has three components: the ground, near, and far horizons. To eliminate the edge-effect, we introduced a multi-resolution halo method. Moreover, we used a new data partition approach, to substantially increase the parallelism in the algorithm. In addition, several optimizations have been applied to considerably reduce the number of arithmetical operations in the core of the algorithm. The experimental results have demonstrated that by applying the above-described contributions, the proposed algorithm is more than twice faster than Stewart's algorithm while maintaining the same accuracy.     

A general-purpose parallel raster processing programming library test application using a geographic cellular automata model

A general-purpose parallel raster processing programming library (pRPL) was developed and applied to speed up a commonly used cellular automaton model with known tractability limitations. The library is suitable for use by geographic information scientists with basic programming skills, but who lack knowledge and experience of parallel computing and programming. pRPL is a general-purpose programming library that provides generic support for raster processing, including local-scope, neighborhood-scope, regional-scope, and global-scope algorithms as long as they are parallelizable. The library also supports multilayer algorithms. Besides the standard data domain decomposition methods, pRPL provides a spatially adaptive quad-tree-based decomposition to produce more evenly distributed workloads among processors. Data parallelism and task parallelism are supported, with both static and dynamic load-balancing. By grouping processors, pRPL also supports data–task hybrid parallelism, i.e., data parallelism within a processor group and task parallelism among processor groups. pSLEUTH, a parallel version of a well-known cellular automata model for simulating urban land-use change (SLEUTH), was developed to demonstrate full utilization of the advanced features of pRPL. Experiments with real-world data sets were conducted and the performance of pSLEUTH measured. We conclude not only that pRPL greatly reduces the development complexity of implementing a parallel raster-processing algorithm, it also greatly reduces the computing time of computationally intensive raster-processing algorithms, as demonstrated with pSLEUTH.     

当代云计算发展研究现状

地理信息技术和地理信息产业作为信息产业的重要组成部分,一直与其同步发展或紧随其后。目前,第三次信息化浪潮和未来技术的代表云计算正在迅速兴起,全球各大IT公司竞相进入云计算领域,抢占制高点;我国也高度重视这一战略性新兴产业,呈现出科研先行,政府推动,企业参与,风起"云"涌的态势。全球学术界和企业界密切协作,有力推动了云计算技术的发展。测绘地理信息界需要了解国际国内云计算研究发展现状。     

Anticipating ubiquitous computing: Logics to forecast technological futures

Visions of the future predict spaces apparently teaming with ever more novel and pervasive technologies. Significant amongst such forecasts is the notion of ‘ubiquitous computing’ (ubicomp), understood as an affordance or capacity tied (in)to people, places and things. This article stages an encounter between the futurity of ubicomp and recent debates in geography around anticipation. So, first, the future orientation in ubicomp research and development (R&D) is investigated as a mode of anticipation. ‘Knowledges’, and ‘logics’ of anticipation are subsequently, and second, discussed as the conceptual apparatus that constructs and perpetuates the ‘proximate future’ of ubicomp. This analysis connects recent discussion about ‘anticipation’ in social sciences research with the methods of ubicomp research, which fits with an emergent agenda around futurity in human geography. Third, the conceptual articulation of ‘anticipatory logic’ is applied to the analysis of empirical investigations of ubicomp R&D to identify the specific logics of anticipation at play. This article accordingly examines the logics of anticipation that both support and destabilise the certainty with which the future is imagined within ubicomp. In conclusion, the multiple ways of anticipating a future world and the ways in which they discipline understandings of futurity are framed as a politics of anticipation.     

相邻结构的高效阻尼控制

提出了相邻结构高效阻尼控制的概念,并基于双液缸的放大原理提出了一处相应的装置,该装置通过放大相邻结构间的振动差别,使阻尼器具有更大的变形和速度,从而更高效地工作,文章阐明了该装置的工作原理,建立了两相邻结构高效阻尼控制体系的运动方程,并对此进行了计算机仿真分析,结果表明,高效阻尼控制的概念是正常的,本文提出的控制装置是有效的,可取得远优于普通阻尼控制的效果。     

基于云计算技术的常用坐标转换实现

云计算技术可以使计算能力在Internet范围内无限扩展,使通过多点提供无限多的服务成为可能.通过PHP、JavaScript、AJAX 三种技术的结合,可以实现云计算.常用坐标转换是指测量中经常用到的几种坐标转换方法.常用坐标转换方法通过云计算技术实现,可以在Internet范围内提供坐标转换服务,这种应用带来的效率...     

高分辨率遥感影像并行分割结果缝合算法

采用基于数据并行的遥感影像分割实现过程,提出了一种新的数据缝合算法解决分割结果合并问题。分割效果对比和运算效率分析等实验结果表明,此算法保持了分割结果合并后的边界正确性,使并行化分割在提高运算效率的同时保证了分割结果的可信度。