written by gunther gerlach-2009
Everyone has an opinion on what is cloud computing. It can be the ability to rent a server or a thousand servers and run a geophysical modeling application on the most powerful systems available anywhere. It can be the ability to rent a virtual server, load software on it, turn it on and off at will, or clone it ten times to meet a sudden workload demand. It can be storing and securing immense amounts of data that is accessible only by authorized applications and users. It can be supported by a cloud provider that sets up a platform that includes the OS, Apache, a MySQL database, Perl, Python, and PHP with the ability to scale automatically in response to changing workloads.
Gunther Gerlach
written by gunther gerlach-2009
The assimilation of services through service ecosystems presents major integration development and maintenance costs. Service providers need to compose their services effectively in coordination with other services if they are to engage in oncoming market opportunities and situations. Further up the supply and distribution chain, if services are to be brokered and delivered through other intermediaries (e.g., for authentication, payment, device-specific service presentations), they will need to be interfaced with service delivery components that operate in various ways. Thus, one can expect that services will have to interact with one another in ways not necessarily foreseen during their development or deployment. A key challenge in this setting is service mediation: the act of repurposing existing services so that they can interact in unforeseen manners by intercepting, storing, transforming, and routing messages going into and out of these services.
Gunther Gerlach
written by gunther gerlach-2009
In wider spanning service ecosystems, several service providers may offer functionally replaceable services that differ in their extra-functional characteristics, such as usage terms and quality of service delivery. Service providers need to be responsive – potentially in real-time – to negotiate variations of service delivery requirements (e.g., price, deliverable timetable). Service ecosystems should therefore explicitly support the negotiation process, reducing non-critical human involvement and providing decision-makers with the information they require to formulate and assess service offers.
Gunther Gerlach
written by gunther gerlach-2009
Internet commerce has created newer forms of service interactions than traditional marketplace transactions. Amazon/UKOnline, single-consumer-to-service transactions – e.g., making customer listings, doing basic look-ups and verification checks, and purchasing goods – are giving way to more distributed, pull-oriented and data streaming modes of interaction on the web. Marketplace auctions, voting, and subscription-based RSS feeds are enhancing wider spans of participants and semistructured, audio and video data in conventional transactional forms.
Gunther Gerlach
written by gunther gerlach-2009
Current provisions for discovery are based on keyword searches through repositories. Keywords are nominated by service providers through publication and advertising features of software as a service (SaaS) functions. Details of message inputs, outputs, and methods are also captured from WSDL file scans and factored into searches.
Such discovery techniques are suitable in tightly coupled and well-scoped domains where service consumers can determine what services offer and how they can be independently utilized from search results. In other words, users are expected to know what they want before they search.
Gunther Gerlach
written by gunther gerlach-2009
As seen through this section, web service ecosystems can generally be described as a logical collection of web services whose exposure and access are subject to constraints, which are characteristic of business service delivery. A lower level analogy can be found with application servers, where access and inter-operation of components is regulated by middleware functions such as discovery/brokering, remote access, object pooling, transactions, asynchronous messaging, persistence management, and so on.
Gunther Gerlach
