Week 10 Flashcards
Define Web services
Web services are self-contained, self-describing, modular applications that can be published, located, and invoked across the Web. Web services perform functions, which can be anything from simple requests to complicated business processes. Once a Web service is deployed, other applications (and other Web services) can discover and invoke the deployed service.
Discuss the relationship between the web services infrastructure and intelligent agents for
e-commerce.
A software agent needs a computer-interpretable description of the service, and the means by which it is accessed. The web-services offer a means to achieve that. They can be located and invoked. Web services provide description of how to invoke them.
Web Services platform consists of four elements. What are those elements?
XML documents with schema descriptions (XSD) rather than DTDs
A remote invocation protocol (SOAP), layered on top of HTTP or SMTP
A directory for advertising and locating services (UDDI)
A language for expression of service characteristics (WSDL)
What are the two documents that can be used to describe the structure of xml document?
Xml document structure can be described by DTD and XML Schema.
What are the basic difference between DTD and Schema?
The purpose is the same, both defines XML document structure but in a different way. The main differences are:
The root element of every XML Schema is named “schema”, and has a number of attributes. In DTD, the root element is the first element the xml doducment starts with.
Each element in Schema has a “name” and attribute “type”.
The attribute “type” can be “complex”, “string”, “date” etc.
The support of data data types is one the strengths of Schema, e.g., “date” data type is of good use.
Describe the basic structure of a SOAP message.
The basic structure of a SOAP message is
- a header for use by the transport protocol
- an envelope for describing a method call
- a body that contains either a request or a response
Briefly describe UDDI and WSDL.
UDDI provides a mechanism for clients to dynamically find other web services. Using a UDDI Interface, businesses can dynamically connect to services provided by external business partners. A UDDI registry has two kinds of clients: businesses that want to publish a service (and its usage
interfaces), and clients who want to obtain services of a certain kind.You can think of UDDI registry service conceptually similar to “yellow page” business directory. For example, you want get your car serviced, you look up at the relevant section of “yellow page” and find contact details of car service centers and then contact them and seek their service. The “yellow page” here do not offer the service, but direct you to those who offers that particular service. UDDI concept is similar to this.
WSDL is a Web Service Description Language that provides a way for service providers to describe the basic format of web service requests over different protocols or encodings. WSDL is used to describe what a web service can do, where it resides, and how to invoke it.
What do you understand by Semantic Web and its goal?
The “Semantic Web” is a vision of the future of the web in terms of Metadata, Ontologies, and Agents.
Definite Resource Description Framework (RDF). What role it can play to industry facilitate
commerce?
The Resource Description Framework (RDF) is a language for representing information about resources. It is particularly intended for representing metadata about Web resources, such as the title, author, and modification date of a Web page, copyright and licensing information about a Web document, or the availability schedule for some shared resource.
See the slide in lecture on “Asset Visibility – Anywhere” where RFID (Radio Frequency Identification) based EPC (Electronic Product Code) can be used to track any product from production line to sell. It can revolutionize inventory control, increase product handling efficiency, boost productivity and customer service.
