Sensor Web的SOS服务研究与实现

Sensor Web是NASA/Jet Propulsion Laboratory(JPL)的Kevin Delin首先提出并将其定义为被部署用来监控和探测新环境,内部能够相互通信的分布式传感器组成的网络系统。自OGC提出Sensor Web的相关标准以来,传感器监测服务SOS就是最基本最核心的服务规范。文章首先对SWE的传感器观测服务SOS核心操作进行介绍,然后设计了传感器观测服务SOS架构,并对每层作了说明,利用Java、Tomcat等技术对SOS的架构进行部署和测试。利用所部署的SOS架构中的核心操作可获取实时或历史的观测数据。     

I3WSN: Industrial Intelligent Wireless Sensor Networks for indoor environments

Sensor Web Enablement (SWE) technologies have been successfully applied to a great variety of outdoor scenarios but, in practical terms, little effort has been applied for indoor environments, and even less in the field of industrial applications. This article presents an intelligent SWE application for an indoor and industrial scenario, with the aim of improving and increasing the levels of human safety. The base low-level architecture is built on top of wireless sensor networks (WSN) connected to a Sensor Observation Service (SOS). Higher layers in the architecture include services that make real time decisions based on the collected data. Both simulation and experimental results are presented. The paper shows the viability of our approach in terms of performance, scalability, modularity and safety.     

PolarHub: A large-scale web crawling engine for OGC service discovery in cyberinfrastructure

The advancement of geospatial interoperability research has fostered the proliferation of geospatial resources that are shared and made publicly available on the Web. However, their increasingly availability has made the identification of the web signature of voluminous geospatial resources a major challenge. In this paper, we introduce our solution of a new cyberinfrastructure platform, the PolarHub, that conducts large-scale web crawling to discover distributed geospatial data and service resources and accomplish this goal efficiently and effectively. The PolarHub is built-upon a service-oriented architecture (SOA) and adopts Data Access Object (DAO)-based software design pattern to ensure the extendibility of the software system. The proposed meta-search-based seed selection and pattern-matching based crawling strategy facilitates the rapid resource identification and discovery through constraining the search scope on the Web. In addition, PolarHub introduces the use of advanced asynchronous communication strategy, which combines client-pull and server-push to ensure high efficiency of the crawling system. These unique design features of PolarHub enable a high performance, scalable, sustainable, collaborative, and interactive platform for active geospatial data discovery. Because of OGC's widespread adoption, OGC-compliant web services become the primary search target of PolarHub. Currently, the PolarHub system is up and running and is serving various scientific community that demands geospatial data. We consider PolarHub a significant contribution to the field of information retrieval and geospatial interoperability.     

Sharing geospatial provenance in a service-oriented environment

One of the earliest investigations of provenance was inspired by applications in GIS in the early 1990’s. Provenance records the processing history of a data product. It provides an information context to help users determine the reliability of data products. Conventional provenance applications in GIS focus on provenance capture, representation, and usage in a stand-alone environment such as a desktop-based GIS software system. They cannot support wide sharing and open access of provenance in a distributed environment. The growth of service-oriented sharing and processing of geospatial data brings some new challenges in provenance-aware applications. One is how to share geospatial provenance in an interoperable way. This paper describes the development of provenance service for geospatial data products using the ebXML Registry Information Model (ebRIM) of a geospatial catalog service, which follows the interface specifications of the OGC Catalogue Services for the Web (CSW). This approach fits well the current service stack of the GIS domain and facilitates the management of geospatial data provenance in an open and distributed environment.     

Publishing sensor observations into Geospatial Information Infrastructures: A use case in fire danger assessment

To improve environmental monitoring, the availability of large coverage, interoperable spatio-temporal data is crucial for its integration into environmental models, for example, to compute fire danger models. In order to produce up-to-date and accurate results, these models require data with high temporal and spatial resolution. Thus, it is promising to consider the increasing number of in-situ sensors providing observations of our environment in real-time. Today, interoperable access to such spatio-temporal data is achieved by Geospatial Information Infrastructures (GIIs). From a technical point of view, GIIs provide these data through standards-based Web service interfaces. While those Web service interfaces already enable the interoperable discovery and retrieval of sensor observations, the functionality to publish sensor observations is still an arduous task. Hence, in this paper, we present an approach to improve the registration of sensors and the publication of their observations via standards-based Web service interfaces. We evaluate our approach by extending a standards-based GII and by applying the developed approach as a proof of concept to integrate in-situ weather observations into the European Forest Fire Information System for assessing fire danger in Spain.     

基于OGC SOS标准的多传感器观测数据共享方法研究

针对传感器网络之间缺乏互操作性和互通性等问题,构建了传感器观测服务的共享数据模型,建立了传感器观测数据共享数据库,基于OGC SOS标准规范,提出了传感器观测数据共享框架,部署了三层网络模型的SOS服务器,屏蔽了传感器网络、信息交换方式和通信格式的异构性问题,实现了对多传感器间观测数据的互操作与共享的支持,并以不同传感器的不同观测属性的数据为例进行了实验,实验表明本文的共享方法能够实现传感器观测数据的共享与集成应用.     

BiSNET: A biologically-inspired middleware architecture for self-managing wireless sensor networks

This paper describes BiSNET (Biologically-inspired architecture for Sensor NETworks), a middleware architecture that addresses several key issues in multi-modal wireless sensor networks (MWSNs) such as autonomy, scalability, adaptability, self-healing and simplicity. Based on the observation that various biological systems have developed mechanisms to overcome these issues, BiSNET follows certain biological principles such as decentralization, food gathering/storage and natural selection to design MWSN applications. In BiSNET, each application consists of multiple software agents, which operate on the BiSNET middleware platform in individual sensor nodes, and each agent exploits certain biologically-inspired mechanisms such as energy exchange, pheromone emission, replication, migration and death. This is analogous to a bee colony (application) consisting of multiple bees (agents). This paper describes the biologically-inspired mechanisms in BiSNET, and evaluates their impacts on the autonomy, scalability, adaptability, self-healing and simplicity of MWSNs. Simulation results show that BiSNET allows sensor nodes (agents and platforms) to be scalable with respect to network size, autonomously adapt their sleep periods for power efficiency and responsiveness of data collection, adaptively aggregate data from different types of sensor nodes, and collectively self-heal (i.e., detect and eliminate) false positive sensor data. The BiSNET platform is implemented simple in its design and lightweight in its memory footprint.     

无人机空中通信数据库信息盲检索系统设计

对无人机空中通信数据库信息盲检索系统进行设计,能够有效解决传统盲检索系统存在的数据召回率低、细粒度差、检索准确度低及实时性差等问题。先给出无人机空中通信数据库信息盲检索系统的总体架构设计,通过对存储器结构进行改进,实现系统硬件部分的优化;采用Java语言和嵌入式开发库设计可视化检索页面,选取检索信息,增设中间件搜索功能,通过盲检索功能的实现,完成系统软件部分的开发,从而设计出无人机空中通信数据库信息盲检索系统。实验结果表明,该系统数据召回率高,细粒度强,检索准确度高,实时性好。     

Web全文检索中间件的设计与应用

为了更好地为Web站内检索提供服务,对Web全文检索的关键技术进行了研究,设计并实现了一个用于Web全文检索的中间件。该中间件通过多线程网页爬虫程序来抓取网页;对抓取结果采用基于Bloom-Filter的大规模URL去重算法来进行高效消重;应用所提出的新的基于标签的正文提取方法来进行网页正文提取,实验结果表明该正文提取方法是有效可行的;此外,为了改善用户的搜索体验,该中间件还提供了一些个性化搜索辅助功能。最后,实现了一个完整的博客搜索系统Boso(博搜)来验证中间件的性能,结果说明该中间件是可以投入实际应用的。     

移动网络中Web服务应用架构研究

提出一个应用于移动网络的Web服务交互通信体系架构,其将基于XML的系统通信的负担从移动客户转移到外部中间件上,该中间件像网关一样,使用快速的二进制协议以客户/服务器方式与移动设备进行轻量级通信,并同时负责解析对Web服务的请求。     

A context-aware middleware for real-time semantic enrichment of distributed multimedia metadata

This paper investigates the problem of the real-time integration and processing of multimedia metadata collected by a distributed sensor network. The discussed practical problem is the efficiency of the technologies used in creating a Knowledge Base in real-time. Specifically, an approach is proposed for the real-time, rule-based semantic enrichment of lower level context features with higher-level semantics. The distinguishing characteristic is the provision of an intelligent middleware-based architecture on which low level components such as sensors, feature extraction algorithms, data sources, and high level components such as application-specific ontologies can be plugged. Throughout the paper, Priamos, a middleware architecture based on Semantic Web technologies is presented, together with a stress-test of the system’s operation under two test case scenarios: A smart security surveillance application and a smart meeting room application. Performance measurements are conducted and corresponding results are exposed.     

Agent-as-a-service-based geospatial service aggregation in the cloud: A case study of flood response

An Agent-as-a-Service (AaaS)-based geospatial service aggregation is proposed to build a more efficient, robust and intelligent geospatial service system in the Cloud for flood emergency response. It involves an AaaS infrastructure, encompassing the mechanisms and algorithms for geospatial Web Processing Service (WPS) generation, geoprocessing and aggregation. The method has the following advantages: 1) it allows separately hosted services and data to work together, avoiding transfers of large volumes of spatial data over the network; 2) it enriches geospatial service resources in the distributed environment by utilizing the agent cloning, migration and service regeneration capabilities of the AaaS, solving issues associated with lack of geospatial services to a certain extent; 3) it enables the migration of services to target nodes to finish a task, strengthening decentralization and enhancing the robustness of geospatial service aggregation; and 4) it helps domain experts and authorities solve interdisciplinary emergency issues using various Agent-generated geospatial services.     

基于本体的网络空间决策支持系统研究*

为了不同的空间决策,往往需要建立相应的空间决策支持系统,在这些空间决策支持系统中,大量的空间数据和模型是可以被重复使用的,因此提出了一种基于本体的空间决策支持系统。该系统能够高效、自动地利用互联网中存在的各类异构空间信息与分析资源来支持空间决策;此外,本系统还提出了一种灵活的体系架构来解决空间决策中存在的语义问题。     

基于HBase 的农业无线传感信息存储系统

无线传感网络由于分布的跨区域性,随着无线传感网络的扩张,如何高效组织存储这些跨区域的大规模的传感数据是近年来研究的热点和难点。根据大规模传感器数量大、分布广的特点,设计使用分层次的分布式存储方案。Hadoop的HBase是一个分布式的数据库,提供实时读写、随即访问、高可扩展性和高可用性的存储服务。使用HBase构建两层存储架构,分别存放区域内传感器数据和传感器数据的元数据。实验表明,该系统有良好的扩展性、存储和查询效率,能够满足大规模传感器数据的存储问题。     

Automatic geospatial metadata generation for earth science virtual data products

Recent advances in Semantic Web and Web Service technologies has shown promise for automatically deriving geospatial information and knowledge from Earth science data distributed over the Web. In a service-oriented environment, the data, information, and knowledge are often consumed or produced by complex, distributed geoscientific workflows or service chains. In order for the chaining results to be consumable, sufficient metadata for data products to be delivered by service chains must be provided. This paper proposes automatic generation of geospatial metadata for Earth science virtual data products. A virtual data product is represented using process models, and can be materialized on demand by dynamically binding and chaining archived data and services, as opposed to requiring that Earth science data products be physically archived. Semantics-enabled geospatial metadata is generated, validated, and propagated during the materialization of a virtual data product. The generated metadata not only provides a context in which end-users can interpret data products before intensive execution of service chains, but also assures semantic consistency of the service chains.     

Future Internet technologies for environmental applications

This paper investigates the usability of Future Internet technologies (aka “Generic Enablers of the Future Internet”) in the context of environmental applications. The paper incorporates the best aspects of the state-of-the-art in environmental informatics with geospatial solutions and scalable processing capabilities of Internet-based tools. It specifically targets the promotion of the “Environmental Observation Web” as an observation-centric paradigm for building the next generation of environmental applications. In the Environmental Observation Web, the great majority of data are considered as observations. These can be generated from sensors (hardware), numerical simulations (models), as well as by humans (human sensors). Independently from the observation provenance and application scope, data can be represented and processed in a standardised way in order to understand environmental processes and their interdependencies. The development of cross-domain applications is then leveraged by technologies such as Cloud Computing, Internet of Things, Big Data Processing and Analytics. For example, “the cloud” can satisfy the peak-performance needs of applications which may occasionally use large amounts of processing power at a fraction of the price of a dedicated server farm. The paper also addresses the need for Specific Enablers that connect mainstream Future Internet capabilities with sensor and geospatial technologies. Main categories of such Specific Enablers are described with an overall architectural approach for developing environmental applications and exemplar use cases.