Semantic Web Programming

Chapter 12. Developing and Using Semantic Services

"Quality in a service or product is not what you put into it. It is what the client or customer gets out of it."

—Peter F. Drucker

Semantic Services (usually called Semantic Web Services, or SWS) are an additional step beyond today's web services, much like the Semantic Web itself is an extension of the original World Wide Web. Web services describe those services that support the traditional SOAP-based or RESTful architectures.

There exist thousands of traditional web services today. However, the ability to integrate and combine them into useful mash-ups requires extensive manual work. The developer must examine each service for its value or semantics and then determine how to extract that value through the correct syntax and protocol. This work severely limits the complexity of mash-ups using traditional web services. Most mash-ups limit the integration to a handful of services, such as Amazon, YahooMaps, or GoogleMaps. In addition, there is limited "contractual agreement" on the various web service interfaces. Interfaces can be modified or removed by their providers at any time, and developers who use these services may never know that changes have taken place until their dependent applications no longer work. This situation makes mash-ups brittle and vulnerable to a change in any of the underlying services.

Analogous to semantic information, SWS directly addresses these limitations by exposing a uniform, machine-readable way to ...