On generalised and specialised spatial information grids: are geo-services ready?

Abstract

After the set-up of a spatial data infrastructure (SDI) and a national information infrastructure (NII) in many countries, the provision of geo-services became one of the most important and attractive tasks. With the integration of global positioning system (GPS), geographic information system (GIS) and remote sensing (RS), we can, in principle, answer any geo-spatial related question: when and where what object has which changes? An intelligent geo-service agent could provide end-users with the most necessary information in the shortest time and at the lowest cost. Unfortunately there is still a long way to go to achieve such goals. The central component in such geo-services is the integration of the spatial information system with a computing grid via wire- and wireless communication networks. This paper will mainly discuss the grid technology and its integration with spatial information technology, expounding potential problems and possible resolutions. A novel categorising of information grids in the context of geo-spatial information is proposed: generalised and specialised spatial information grids.     

Graphics processing unit-based dynamic volume rendering for typhoons on a virtual globe

Typhoons are usually accompanied by strong winds, heavy rain, storm surges and other disastrous events, and they are the most severe weather phenomena in the western part of the North Pacific Ocean. Visualisation is a key technology for analysing and presenting climate simulations and observations together with related social and ecological data. Virtual globes are a logical platform for visualising such geospatial data via the Internet. To implement interactive visualisation of typhoon data within virtual globes, this study provides a 3D texture-mapping algorithm to render volume textures on a globe. In addition, a systematic framework is proposed in which a hierarchical octree-based multiresolution data structure is implemented to organise the large volume dataset, and a graphics processing unit-based dynamic interpolation approach is proposed to obtain a smooth effect. Finally, the structure is combined with a level of detail strategy to enable the rendering of dynamic volumetric data at an acceptable interactive frame rate. To demonstrate the capabilities of this framework, data for a simulated typhoon event were rendered in World Wind, an open-source virtual globe. The experimental results demonstrate that the application of the proposed strategies can result in an interactive visualisation performance that renders typhoon data on virtual globes.     

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。     

3D GIS支持下盐腔围岩三维计算模型的生成

目前盐腔围岩蠕变模拟中计算网格生成多是理想化的,并没有充分利用真实探测数据。针对这些问题,提出了一种新的三维计算模型生成方法。借助HalfEdge数据结构,基于研究区域边界、DEM（digital element model,数字高程模型）和钻井数据,构建了研究区域地层三维模型;基于声纳测腔数据构建了盐腔三维模型,并对其进行了拓扑检查与修正;将地层三维模型与盐腔三维模型进行三维空间布尔运算,获取盐腔围岩三维模型;通过对该模型进行三维空间网格离散,得到盐腔围岩四面体网格单元,即数值模拟计算模型。通过该方法构建的三维计算模型,可以为后期盐腔围岩蠕变数值模拟过程提供有效的计算网格,进而可以为盐腔的建造,尤其是安全合理地利用盐腔提供科学依据和技术支持。     

基于集群的影像并行OPTA算法研究

并行计算是提高海量遥感影像细化处理速度的有效途径.基于对OPTA细化算法的分析,深入研究OPTA细化并行算法中数据划分和数据通信优化等关键问题,提出一种适合集群并行处理的通信优化并行算法,实验证明该算法具有良好的加速比,适合集群计算环境下海量遥感影像的细化处理.     

利用流水线技术的遥感影像并行处理

针对现有的OpenMP和直接的线程并行法难以对遥感影像处理链进行加速的问题,引入流水线概念对复杂的功能链进行并行加速,提出了基于流水线技术的遥感影像并行处理方法。影像处理实验验证了流水线在遥感影像多级连续处理方面的优势。     

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.     

Model tree approach for prediction of pile groups scour due to waves

Scour around piles could endanger the stability of the structures placed on them. Hence, an accurate estimation of the scour depth around piles is very important in coastal and marine engineering. Due to the complex interaction between the wave, seabed and pile group; prediction of the scour depth is not an easy task and the available empirical formulas have limited accuracy. Recently, soft computing methods such as Artificial Neural Networks (ANNs) and Support Vector Machines (SVMs) have been used for the prediction of the scour depth. However, these methods do not give enough insight about the process and are not as easy to use as the empirical equations. In this study, new formulas are given that are easy to use, accurate and physically sound. Available empirical equations for estimating the pile group scour depth such as those of Sumer et al. (1992) and Bayram and Larson (2000), are less accurate compared to the given equations. These equations are as accurate as other soft computing methods such as ANN and SVM. Moreover, in this study, safety factors are given for different levels of acceptable risks, which can be so useful for engineers.     

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...     

从云计算到雾计算的范式转变

虽然云计算的应用越来越广泛,但也具有不能支持高移动性、不支持地理位置信息及高时延等亟待解决的问题.为此,雾计算已经出现,并将云计算扩展到网络的边缘,以减少延迟和网络拥塞.首先介绍了雾计算的概念、特点和结构,然后讨论了具有代表性的应用场景以及雾计算的安全问题.另外,还对雾计算相似的原位计算和连续计算进行了介绍.最后,给出了云计算与雾计算的区别与联系,并分析了雾计算未来的发展方向.雾计算扩大了以云计算为特征的网络计算范式,将网络计算从网络的中心扩展到网络的边缘,从而可以更加广泛地运用于更多的应用形态和服务类型.