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。     

基于网格的空间信息原子服务互操作与集成框架

提出了空间信息原子服务的概念，阐述了其互操作模型与互操作层次结构，进而提出了空间信息原子服务的集成框架，包括服务分类框架、服务链接模式以及由空间信息原子服务、分子服务、流程服务和方案服务组成的服务集成模型。空间信息原子服务概念的提出，对于空间信息服务(GIService)的服务组织与管理、服务集成以及更好地实现软件复用和空间信息互操作等都具有重要的意义。     

Semantic Enablement for Spatial Data Infrastructures

Building on abstract reference models, the Open Geospatial Consortium (OGC) has established standards for storing, discovering, and processing geographical information. These standards act as a basis for the implementation of specific services and Spatial Data Infrastructures (SDI). Research on geo‐semantics plays an increasing role to support complex queries and retrieval across heterogeneous information sources, as well as for service orchestration, semantic translation, and on‐the‐fly integration. So far, this research targets individual solutions or focuses on the Semantic Web, leaving the integration into SDI aside. What is missing is a shared and transparent Semantic Enablement Layer for SDI which also integrates reasoning services known from the Semantic Web. Instead of developing new semantically enabled services from scratch, we propose to create profiles of existing services that implement a transparent mapping between the OGC and the Semantic Web world. Finally, we point out how to combine SDI with linked data.     

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.     

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。     

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。     

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。     

A capability matching and ontology reasoning method for high precision OGC web service discovery

Finding the right spatially aware web service in a heterogeneous distributed environment using criteria such as service type, version, time, space, and scale has become a challenge in the integration of geospatial information services. A new method for retrieving Open Geospatial Consortium (OGC) Web Service (OWS) that deals with this challenge using page crawling, link detection, service capability matching, and ontology reasoning, is described in this paper. Its major components are distributed OWS, the OWS search engine, the OWS ontology generator, the ontology-based OWS catalog service, and the ontology-based multi-protocol OWS client. Experimental results show that the execution time of this proposed method equals only 0.26 of that of Nutch's method. In addition, the precision is much higher. Moreover, this proposed method can carry out complex OWS reasoning-based queries. It is being used successfully for the Antarctica multi-protocol OWS portal of the Geo-Information Web Service Portal of the Polar.     

组件与服务耦合的地学模型集成方法与实现

传统的空间信息处理建模工具,如ArcGIS ModelBuilder,聚焦于地理空间信息处理算子的组合建模。“模型网”的提出对已有的空间信息处理建模工具提出了新的挑战,一方面,现有的空间信息处理建模工具需要能够支持网络环境,支持空间信息服务的即插即用;另一方面,服务需要与复杂地学模型耦合,支持基于时间步长的地学模型运行。针对组件与服务并存的现状以及异构模型和算法兼容性差等问题,提出了组件与服务耦合的地学模型集成方法;并从“模型即服务”和模型集成需求出发,提出了基于WebSocket协议发布地学模型的新方法,实现了基于时间步长的地学模型在线共享。采用科学工作流技术实现了遵循国际开放地理空间信息联盟（Open Geospatial Consortium,OGC）标准的空间信息服务、基于WebSocket协议的地学模型服务、遵循OpenMI开放建模接口规范的模型组件集成,具有逻辑一致、物理分隔、执行可控等特点。利用该方法将传统的空间信息处理建模工具拓展为地学模型集成工具,并应用于具体案例中,验证了方法的可行性。     

网格环境下地理数据服务集成模式

在分析我国地理信息集成服务应用现状的基础上,比较现有网格环境下地理数据服务集成模式及其问题,讨论面向地理数据服务的地理数据集成模式的优势。并将Web Service技术引入到传统的地理数据服务集成中,构建一种基于网格的分布式地理数据集成模式,提出地理数据服务集成框架。     

基于Agent的空间信息服务组合研究

首先简要介绍了空间信息服务的研究现状,然后分析了空间信息服务组合的3种主要形式。总结了Agent技术实现聚合式空间信息服务组合的优势,指出Agent的自主性、交互性等特性是解决开放环境下空间信息服务的发现、选择以及组合问题的最佳途径之一。详细设计了基于Agent的空间信息服务模型,阐述了服务发现、服务组合、用户交互3部分的结构和功能,引入词频向量的方法解决服务发现和匹配问题,最后构造了一个基于Agent的空间信息服务组合的用例。     

空间信息RESTful网络服务语义注册方法研究

为了提高语义标注过程的效率,研究了自动化语义标注空间信息RESTful网络服务的方法,该方法通过在数据网络中,查找网络服务输入输出参数的匹配项,从而实现自动标注。将语义标注结果通过SPARQL端点服务发布,便于标注结果在服务发现过程中的应用。     

Quality of service management framework for dynamic chaining of geographic information services

Dynamic chaining of geographic information services (geo-services) is gaining popularity as a new paradigm for evolving flexible geo-information systems and for providing on-demand access to geo-information. In dynamic chaining, disparate geo-services are discovered and composed at run time to yield more elaborate functionality and create value-added geo-information. Common approaches to service chaining discover and compose disparate geo-services based on the functional capability of individual geo-services. The primary concern of common approaches is thus the emergent behavior of the resulting composite geo-service. However, as geo-services become mundane and take on a greater and more strategic role in mission critical processes, deliverable quality of service (QoS) becomes an important concern. QoS concerns operational characteristics of a service that determine its utility in an application context. To address pertinent QoS requirements, a new approach to service chaining becomes necessary. In this paper we propose a QoS-aware chaining approach in which geo-services are discovered, composed and executed considering both functional and QoS requirements. We prescribe a QoS management framework that defines fundamental principles, concepts and mechanisms which can be applied to evolve an effective distributed computing platform for QoS-aware chaining of geo-services – the so-called geo-service infrastructure. The paper also defines an extensible QoS model for services delivered by dynamic compositions of geo-services. The process of orthophoto generation is used to demonstrate the applicability of the prescribed framework to service-oriented geographic information processing.     

GeoPW: Laying Blocks for the Geospatial Processing Web

Recent advances in Web‐related technologies have significantly promoted the wide sharing and integrated analysis of distributed geospatial data. Geospatial applications often involve diverse sources of data and complex geoprocessing functions. Existing Web‐based GIS focuses more on access to distributed geospatial data. In scientific problem solving, the ability to carry out geospatial analysis is essential to geoscientific discovery. This article presents the design and implementation of GeoPW, a set of services providing geoprocessing functions over the Web. The concept of the Geospatial Processing Web is discussed to address the geoprocessing demands in the emerging information infrastructure, and the role of GeoPW in establishing the Geospatial Processing Web is identified. The services in GeoPW are implemented by developing middleware that wraps legacy GIS analysis components to provide a large number of geoprocessing utilities over the Web. These services are open and accessible to the public, and they support integrated geoprocessing on the Web.     

空间服务语义模式的地理信息服务发现

如何从大规模地理信息服务集合中快速且准确地发现目标服务是地理信息服务应用中的一个关键问题。当前基于关键字的服务发现方式缺乏语义支持,搜索效率低。本文在WSMO/WSML框架下,提出了一种基于空间服务语义模式的服务发现方法,将地理信息从语法模式转换为语义模式,明确表达空间数据中隐含的知识,有效克服数据源之间的语义异构。该方法能够显著提高地理信息服务发现的查全率和查准率。