1,720,957 research outputs found
XML approach to communication design of WebGIS
No full textXML can describe the concept model of inclusion relationship conveniently. Also, it can directly express the concept model in an understandable way, and the expression format is so flexible that no useless element will be included there. While describing communication protocols by XML, we can not only give a common format for data and control commands, but also reuse the existing XML-parsers, so as to facilitate the expansibility and integration of protocols in a system, W3C had proposed Simple Object Access Protocol (SOAP) [1], which is a light weight protocol based on XML used to build information exchange framework under distributed environments. ArcInfo's ArcIMS also used ArcXML as the fundamental command and data transmission protocols to communicate between users' web pages and backend spatial data servers [2]. Our idea of XML based communication protocols for WebGIS benefits from the SOAP model, but we basically focus on the application in WebGIS. With the aid of UML, the typical requiring and responding protocols of WebGIS are analyzed firstly. Then the mechanism of designing communication protocols following W3C's XML Schema specification is illustrated.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000231171300077&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Information SystemsComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
Spatial information grid - An agent framework
No full textSpatial information grid (SIG) is a spatial information infrastructure that has the capability of providing services on-demand. In this paper, agent technology is adopted to construct a SIG framework, which contains three layers: users/applications layer, agent services layer and information layer. Different applications can get their spatial information via agent services, and agent services make the procedure of navigating and accessing spatial information transparent to users. Also, the implementation issues of the framework are discussed.Computer Science, Artificial IntelligenceComputer Science, Information SystemsComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
A component-based WebGIS Geo-Union
No full textA component-based WebGIS system Geo-Union is introduced, including its architecture, functional partition and web application mode.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000223024600075&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Information SystemsComputer Science, Software EngineeringComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
A cache mechanism for component-based WebGIS
No full textFirst, a component-based WebGIS system Geo-Union is introduced, then the architecture and the web application mode of Geo-Union are discussed. After that, a spatial cache framework is designed and adopted in Geo-Union to improve its performance in network environment. There are three levels of spatial cache: spatial database cache, network spatial cache and spatial data proxy server, and they play different roles in different situations to improve spatial data access performance of Geo-Union.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000223079700121&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Interdisciplinary ApplicationsComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
Design hierarchical component-based WebGIS
No full textA practical component-based WebGIS named as Geo-Union is presented. Geo-Union consists of four layers: storage layer, service layer, component layer and application layer. Service layer can be partitioned into another two layers: client service layer and server service layer. The architectures and object constitutions of each layer in Geo-Union are discussed in details. The Web application model of Geo-Union is also presented. At last, some future works in WebGIS, such as interoperability, security, distributed computing and intelligent computing, are indicated and simply explored.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000230026200071&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
SOM: A novel model for defining topological line-region relations
No full textTopological line-region relations are generally defined by the Ninth-Intersection Model (9IM) or the Dimensionally Extended Ninth-Intersection Model (DE-9IM) in GIS. In the paper, Segment Operator Model (SOM) is introduced to solve the same problem. Let a simple region R filter a simple curve L and produce a set of curve segments within the exterior, the interior or the borders of R. The topological relations between curve segments and R are mapped into seven categories: across, stabsin, along, bowsto, sticksto, inside and disjoint. SOM is based on counting the curve segments that belong to each of the seven categories. Any topological relations defined in 9IM or DE-9IM can be expressed in SOM. In SOM, L is atomic to R when only a single curve segment is produced, simplex to R when no more than three curve segments are produced, otherwise, L is complex to R. L is uniform to R when only one kind of curve segments are produced.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000221852900035&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Interdisciplinary ApplicationsComputer Science, Software EngineeringComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
Load analysis and load control in geo-agents
No full textGeo-Agents is an agent-based distributed Geographic Information System (GIS), which is a multi-agent system and consists of four types of GIS agent: GuServer, Facilitator, interface agent and GIS function agent. For a multi-agent system, there contains many distributed agents in different environments, which form a complex distributed system. In order to improve the performance, load control should be a keystone in a multi-agent system. Firstly, the load problems in Geo-Agents are analyzed, and then two load control strategies are discussed in detail.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000223079700128&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Interdisciplinary ApplicationsComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
Component-based WebGIS and its spatial cache framework
No full textComponent model is a primary approach to deepen the functions of WebGIS. A component-based WebGIS system Geo-Union is introduced. Geo-Union has a multi-level Client/Server architecture, including four layers: application layer, component layer, service layer and storage layer, where service layer has different units to provide both client services and server services. Also, component partition and web mode of Geo-Union is discussed. After that, a spatial cache framework, including spatial database cache, network spatial cache and spatial data proxy server, is designed in Geo-Union to improve spatial data access performance in different situations in network environment.Computer Science, Information SystemsComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
Mapping business workflows onto network services environments
No full textIn order to implement common adaptability in accessing to distributed resources, it is fatal for Web applications to deploy business workflows onto network service environments composed of Web Services and Grid Services. This paper introduces abstract resources and abstract services to express abstract workflows, and uses resources and service instances to express executable workflows that can run in service environments. Thus the deployment and execution of business workflows are transformed into two mappings: mapping of business workflow onto abstract workflows and mapping of abstract workflows onto executable workflows. The definition of relevant parameters used to implement automatic mapping is formulized as Application Template (AT). The most important component of AT is corresponding relation between business functions and abstract workflow fragments. AT also defines restrictions while each abstract services are utilized in certain application tasks, as well as associated service metadata. The latter avoids superfluous metadata by service providers, and simplifies unnecessary details in matching service instances.Computer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
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