Service, Quality of Services

The geo-data infrastructure (GDI) has for long been developed as a network for spatial data discovery and access. As a result spatial data, in distributed and heterogeneous databases, are readily accessible and sharable. Spatial data abundance notwithstanding, a rapidly growing segment of the geoinformation market comprises non-expert GIS users who seldom seek raw data but rather demand value-added information products and services of varying complexity. Increasingly, traditional geo-data infrastructures fail to fully meet the needs of emerging markets. Further, increased competition, demand for lean enterprises, pervasive e-commerce and rapid gravitation towards Internet GIS all compound to motivate the concept of a novel service-centred infrastructure that enables delivery of geo-information services and products typically beyond the capability of any single organization. Such a service-centred infrastructure has variously referred to as the Geographical Services Infrastructure (GSI). The GSI operates as a virtual enterprise comprising dynamic collaborations of many organizations partnering on the basis of core competencies and shared business objectives. The development of such an enterprise requires the design of an integrated platform that enables interoperability and inter-working of functional entities within heterogeneous environment. To facilitate access to GIS services over the Internet (Web GIS Services), mechanisms are needed to coordinate and control the execution of identified services. Workflow management services are suited for the latter set of functions while service brokers support the former. Service brokers maintain registries containing relevant service metadata to aid the discovery of required services. Workflow management services control and coordinate the execution of service chains, both intra- and inter-enterprise, negotiate and enforce adherence to quality o

On quality-aware conposition of geographic information services for disaster management

Dynamic chaining of geographic information services (geo-services) is emerging as a viable framework for evolving flexible geo-information systems, integrating heterogeneous geographically dispersed geoinformation systems, and for providing on-demand access to geographic information in many application domains and location-based services. Alongside functionality, quality of service (QoS) is basic to successful chaining of dispaprate geo-services. This paper explores QoS provisioning in the context of geo-service chaining for disaster management. The paper presents a QoS model for disaster management and illustrates how userlevel QoS requirements can be supported in a QoS-aware geo-service architecture