应用描述词汇约简的OGC地理信息服务演绎推理

针对OGC地理信息服务在地理空间知识的有效组织和表达方面的能力比较弱,缺乏对服务信息的描述,数据丰富而知识缺乏,致使已有的数据在知识的表示和检索上存在缺陷,通过引入地理本体,按照基础地理信息要素分类,对地理信息服务的关键描述词汇进行提取,构建了地理信息服务本体库和实例数据库,应用粗糙集理论建立关键描述词汇约简模型,基于该模型实现了对地理信息服务实例数据库进行知识约简,形成最优实例数据库。最后应用地理信息服务本体库和实例数据库,基于演绎推理模型开发实例原型系统,实现了对地理信息服务对象的语义检索和推理,并通过试验从查全率和查准率两个指标验证了该方法的可行性、有效性和准确性。     

The framework of a geospatial semantic web-based spatial decision support system for Digital Earth

Abstract

While significant progress has been made to implement the Digital Earth vision, current implementation only makes it easy to integrate and share spatial data from distributed sources and has limited capabilities to integrate data and models for simulating social and physical processes. To achieve effectiveness of decision-making using Digital Earth for understanding the Earth and its systems, new infrastructures that provide capabilities of computational simulation are needed. This paper proposed a framework of geospatial semantic web-based interoperable spatial decision support systems (SDSSs) to expand capabilities of the currently implemented infrastructure of Digital Earth. Main technologies applied in the framework such as heterogeneous ontology integration, ontology-based catalog service, and web service composition were introduced. We proposed a partition-refinement algorithm for ontology matching and integration, and an algorithm for web service discovery and composition. The proposed interoperable SDSS enables decision-makers to reuse and integrate geospatial data and geoprocessing resources from heterogeneous sources across the Internet. Based on the proposed framework, a prototype to assist in protective boundary delimitation for Lunan Stone Forest conservation was implemented to demonstrate how ontology-based web services and the services-oriented architecture can contribute to the development of interoperable SDSSs in support of Digital Earth for decision-making.     

基于OGC Web服务模型的城市异构GIS互操作

利用服务共享实现城市异构GIS系统互操作是解决互操作问题的一个新思路。本文首先分析了开放地理信息系统联盟(OGC Open GIS Consortium)的互操作模型(OWS Open GIS Web Service)的框架结构以及服务协作,然后以模型框架中的一个基本数据服务———地图要素服务(Web Feature Service)为例,详细介绍了利用服务共享实现城市异构GIS数据共享与互操作的具体开发过程,最后对该模式的应用前景进行了分析。     

基于XML的地理数据Web服务研究

本文针对大部分GIS系统之间无法很好的沟通和协作而形成地理数据孤岛的问题,提出建立"基于XML的地理数据Web服务"的解决方案,解决多源的、异构的分布式地理数据之间的共享和互操作。研究Web服务的服务种类,提出元数据和地理数据相结合的服务模式。并通过建立测绘、规划、房地等方面的多个地理数据Web服务,提出调用各种地理数据Web服务构建GIS应用系统的具体应用方案。     

Web要素服务的优化方法

基于(Web)XML空间数据互操作规范的方式是目前实现Internet上空间信息共享和互操作的有效途径.Web要素服务是OGC提出的基于(Web)XML空间数据互操作规范中功能最为强大、应用前景最好的一种数据服务.Web要素服务通过GML传递空间数据,但是由于GML描述方式冗余度大,生成和传输GML的时间长,在现有的网络带宽下难以令用户满意.本文介绍从GML模式定义、数据压缩和客户端生成内存结构3个方面提出优化Web要素服务的方法.     

Requirements for Next Generation Spatial Data Infrastructures-Standardized Web Based Geoprocessing and Web Service Orchestration

Spatial Data Infrastructures (SDI) have been widely accepted to exchange geospatial data among organizations. Today SDIs main focus lies on the provision of geospatial data in the form of distributed spatial web services, the retrieval through catalogues, and visualization in the form of Web Map Services (WMS). The hypothesis presented in this paper takes SDI's one step further by providing a method to process geodata in an Open Geospatial Consortium (OGC) compliant way into information. Two case studies present the potential of standardized geoprocessing services. In addition, this paper addresses the problem of service chaining by providing a system architecture to implement complex geoprocessing models and workflows based on web services using Web Service Orchestration (WSO). The proposed methods utilize spatial standards provided by OGC, the International Organization for Standardization (ISO) and ‘mainstream IT’ standards provided by the World Wide Web Consortium (W3C) and the Organization for the Advancement of Structured Information Standards (OASIS) to establish a generic web service architecture for providing common geoprocessing capabilities (e.g. spatial algorithms, map algebra, etc.) for usage in SDIs.     

Designing Service Architectures for Distributed Geoprocessing: Challenges and Future Directions

In this paper we study the feasibility of using services offered by a Spatial Data Infrastructure as a basis for distributed service oriented geoprocessing. By developing a prototype we demonstrate that a Spatial Data Infrastructure facilitates rapid development of applications that solve typical problems for an existing risk management application. The prototype provides users with a distributed application that enables the assessment of fire damage areas based on land cover data in a given area. The services involved in the application include: Web Feature Services, Web Map Services, a Gazetteer Service, a Catalogue Service, and Geoprocessing Services. We present the architecture of the application and describe details about implementation‐specific issues. We conclude that current OGC specifications provide a sound basis for developing service oriented architectures for geographic applications; however, in particular for geoprocessing applications, we question the feasibility of the use of Web Feature Services as data sources for larger amounts of data and call for further research in this direction.     

本体驱动下的地图符号共享方法研究

针对地图符号模型与异构地图符号资源不兼容,难以实现在网络环境下多源异构地图符号的集成与互操作的问题,提出了一种基于本体的地图符号概念模型。通过定义符号的类、属性、关系和约束条件,该模型实现了对符号概念及关系的形式化表达和符号本体的构建。在此基础上,采用SOA软件架构思想,建立了基于Web服务的地图符号分布式共享框架结构,实现了符号的跨平台调用。本研究基于XML Web Services的地图符号与ArcGIS Engine之间的跨平台调用,进行了本符号共享方法的可行性试验。试验结果表明,该方法可以实现网络环境下多源异构地图符号的灵活开放集成和互操作,并且有效地保留了地图符号的语义信息。     

An asynchronous Geoprocessing Workflow and its application to an Antarctic ozone monitoring and mapping service

The integration of Sensor Web Enablement services with other Open Geospatial Consortium (OGC) Web Services as Geospatial Processing Workflows (GPW) is essential for future Sensor Web application scenarios. With the help of GPW technology, distributed and heterogeneous OGC Web Services can be organized and integrated as compound Web Service applications that can direct complicated earth observation tasks. Under the Sensor Web environment, asynchronous communications between Sensor Web Services are common. We have proposed an asynchronous GPW architecture for the integration of Sensor Web Services into a Web Service Business Process Execution Language workflow technology. We designed a Sensor Information Accessing and Processing workflow, an asynchronous GPW instance, to take an experiment of observing and mapping ozone over Antarctica. Based on our results, our proposed asynchronous workflow method shows the advantages of taking environmental monitoring and mapping tasks.     

基于OWL-S的地理信息服务描述和发现

本文建立了地理数据类型本体和地理服务类型本体,提出了基于OWL-S地理理信息服务发现方法。其核心思想是用OWL-S进行服务描述和发布,通过对服务语义描述中的输入、输出、服务分类进行分级匹配实现服务的自动发现。     

基于语义Web的地理服务发现框架

在传统Web服务发现架构中,仅凭接口参数的结构化相似度计算匹配方法远远不能满足复杂地理服务的发现需求。本文结合语义Web知识,设计了地理服务发现框架,框架支持地理服务语义化描述、带有语义信息的服务注册、基于语义推理的服务发现。其中,服务匹配算法是服务发现的关键,本文基于传统的四级匹配算法,提出采用分级匹配思想,并在I/O匹配中利用本体分类树,将本体相似度求解转换为分类树中节点距离求解的方法的地理服务发现匹配算法。实例证明,改进的算法不但能区分匹配等级,而且能区分同一匹配等级之间的相似度大小,能较好地满足地理服务的发现的需求。     

基于J2EE的分布式网络地理信息服务研究

从目前Web领域的发展现状出发,介绍了Web服务和J2EE架构的定义和特点,介绍了基于J2EE架构的Web应用的多层体系结构模式,并在此架构基础上对如何使用现行的Web服务技术开发Web应用进行了研究。最后给出了分布式网络地理信息服务的具体实现方法。     

Event-driven flood management: design and computational modules

Flood management is a set of activities that have to be carried out in collaboration with multiple agencies. Advanced flood information with early warning generated using remote sensing satellite technologies can help the agencies to effectively manage the situation on ground. Various environmental parameters and forecasts provided by different agencies can be analyzed and compared with historical flood events for generating probable flood event alerts. The information (environmental parameters) provided by the agencies are heterogeneous and noncompliant to standards and distributed in nature. Synchronization of data from distributed resources and automation of data analysis process for flood management is a primary prerequisite for faster and efficient decision-making. Web 2.0-based web services enable data creation, sharing, communication, and collaboration on web. Spatial data sharing on web 2.0 for making quality of service using open-source software for efficient flood management is a challenge. Available software architectures proposed for risk and environmental crisis management are too generic in nature and needs lot of modification for flood management. An event-driven model coupled with data standardization procedures using service-oriented architecture provides an effective framework for flood management. In this paper, a framework capable of collecting heterogeneous distributed flood-related information for analyzing and alerting probable flood events is proposed. The framework has been implemented to generate automatic flood extent maps, by analyzing the distributed satellite data (as service). The automation of flood delineation process reduces the overall flood product generation time. Open-source web tools have been utilized in development of spatial information system to visualize and analyze the actual situation on ground facilitating overall decision-making process.     

A Task Ontology Driven Approach for Live Geoprocessing in a Service‐Oriented Environment

In a service‐oriented environment, Web geoprocessing services can provide geoprocessing functions for a variety of applications including Sensor Web. Connecting Sensor Web and geoprocessing services together shows great potentail to support live geoprocessing using real‐time data inputs. This article proposes a task ontology driven approach to live geoprocessing. The task in the ontology contains five aspects: task type, task priority, task constraints, task model, and task process. The use of the task ontology in driving live geoprocessing includes the following steps: (1) Task model generation, which generates a concrete process model to fulfill user demands; (2) Process model instantiation, which transforms the process model into an executable workflow; (3) Workflow execution: the workflow engine executes the workflow to generate value‐added data products using Sensor Web data as inputs. The approach not only helps create semantically correct connections between Sensor Web and Web geoprocessing services, but also provides sharable problem solving knowledge using process models. A prototype system, which leverages Web 2.0, Sensor Web, Semantic Web, and geoprocessing services, is developed to demonstrate the applicability of the approach.     

一种遥感信息服务分类本体构建方法

在分析遥感信息服务的领域特征及其概念的事件名词特点的基础上,结合框架语义学理论,提出了基于事件框架提取遥感信息服务概念的语义特征并在此基础上利用形式概念分析构建遥感信息服务分类本体的方法。实验结果表明了此方法的有效性。     

基于本体语义的地理信息服务发现

基于本体语义研究地理信息服务发现问题.将加权语义距离和Wu-Palmer法相结合并进行改进计算本体概念语义相似度.引入服务接口依赖关系,提出支持接口多态性的本体语义地理信息服务输入输出匹配方法.最后开发实验原型对基于本体的地理信息服务匹配方法进行实验与分析.     

基于网络爬虫的导航深度服务信息自动采集

根据近来对地理信息Web服务搜索引擎的研究,设计一种基于网络爬虫自动采集POI(Point Of Interest)深度服务信息的方法。使用网络爬虫与DOM(Document Object Model)技术从发布相关POI深度服务信息的网站抓取实时信息,并通过编辑距离与针对地址匹配的改进最大公共子序列分析页面内容与POI主题相关度,进而将相关度最高的深度服务信息与POI点匹配,生成深度服务信息点特征。实验证明了方法的有效性。     

一种分布式空间数据的服务聚合模型

数据源的异构、GIS服务规范的自定义以及分布式存放等问题制约了空间信息的广泛共享和应用。本文基于空间信息共享平台建设,围绕服务动态聚合的思想,结合OGC的标准规范和技术思想,在具有REST风格的GIS服务的基础之上,提出了一个服务聚合模型,通过该模型实现了分布式存放的异构瓦片数据的无缝集成显示以及网络要素服务的功能共享。