Web 2.0 E-mail

Good user interactions are fundamental to successful service discovery, selection, adaptation, invocation and service construction via composition, as well as service interaction in an easy to use manner. They are also means to balance the integration of services with the interactions provided by humans.

SOA4All will make use of Web 2.0 technology in its user interfaces. Web 2.0 has been becoming one of the most discussed phrases in the last 2 years in the ICT domain. Web 2.0 can be seen as a principle of providing a new way for human computing interaction. Its main idea is to connect different users allowing them to exchange information and to add value by building communities and networks. In SOA4All Web 2.0 is used on different places and in fact it represents a core of the SOA4All vision. For example, users may tag or rate services or they may connect services in an easy way using mashups. From a technical perspective the SOA4All user interface – called the SOA4All Studio – will be wrapped around Web 2.0 technologies. As an example, the AJAX technology is a central element of the SOA4All Studio interface. It allows SOA4all to provide the next generation of web application interfaces that react instantly to user requests instead of reloading pages on each click. Web 2.0 principles will be utilised to dramatically improve the usability of SOA targeting service consumption and provisioning and providing a ‘level playing field’ for human and machine based computation. The incorporation of Web 2.0 technologies such as mash-ups will facilitate the dynamic creation of new composed functionalities.

Integrating Web 2.0 and SOA

On a basic level Web 2.0 and SOA are both about building on Web-based asynchronous communication to build up application from services. On the other hand, recent movements in ‘AJAX’ have been away from the XML, that the Java asynchronously accesses, and towards lighter-weight representations like JSON (JavaScript Serialized Object Notation), and away from SOAP and towards RESTful services. This is not, we claim, due to a fundamental objection to the Web services approach, but for efficiency since Web services are not delivering advantages for the simple applications currently built (which have complex user interfaces, Microsoft Outlook Web Access and Google Maps being the classic examples, but usually only communication with a single fixed back-end system). Furthermore our position is that more advanced Web 2.0 applications, exemplified by the ‘mashup’ and ‘aggregator’ sites, re-assert requirements that semantic Web services are well-positioned to deliver.

The following table (inspired by Mike Platt and Anne Thomas Manes, Future of Architecture: Beyond Web 2.0 and SOA, presentation at MIX 2006) demonstrates this and illustrates the result of the integration which can be achieved by SOA4All.

  Web 2.0
SOA SOA4All
 Audience
 Consumer Enterprise  All
 Control Decentralized Centralized  Decentralized with local centralization
 Organization Unmanaged Managed Unmanaged with local management
 No. of device types
 Very large
 Small (servers)
 Very large
 No. of devices  Very large
 Large Very large
 Connectivity Global Medium Global
 Total power
 Huge Large Huge
 Total demand
 Huge Large Huge
 Communication Asynchronous REST Asynchronous WS-* Asynchronous WS-* / REST
 Rate of change
 Fast Slow Fast

 

The combination of Web 2.0 and SOA will lead to a number of interesting advances in both spheres.

Mashing Web and Web services

Thanks to the programming paradigm of Asynchronous JavaScript and XML (AJAX), Web sites have become more interactive and user friendly, to an extent that was previously only achieved by desktop applications. Given the ubiquity and abundance of Internet bandwidth today, both stationary as well as wireless, we can see a convergence between classic desktop applications and Web applications. The Web is becoming a valid platform to host all types of software services. AJAX adds the ability to dynamically update the appearance of a Web page from the static “request/response” pattern between Web browser and Web application, where only whole Web pages are displayed. Hence, users experience a more fluid and interactive Web application. Web Service standards such as SOAP and REST are already a prominent component of Web 2.0. Often, external datasets are “mashed-up” with a Web application using their SOAP or REST based interfaces. Thus, Web 2.0 applications often form graphical interfaces for (enterprise) applications based on the SOA paradigm, which has established itself as a prominent architecture for modern back-end applications.

SOA4All is targeted at semantic mash-up sites, which must extend the current simplistic provision for visual composition (mash-up) in Web 2.0 sites. This will require both significant additional intelligent processing and data reconciliation mechanisms. The result should be that the creation of mash-ups is simpler are more efficient. Recently defined Semantic Web standards may also allow mash-ups to be enabled on-the-fly at runtime, and over more than just two data sources.

With a rising number of Web APIs and mash-ups, a new form of mash-up is emerging, namely aggregators. These are similar to mash-ups superficially, but are driven by a different goal. The primary goal of aggregating sites is to collect data from heterogeneous and multiple sources and republish the cleansed, integrated and aggregated data at a single point-of-access. These suffer from the well-known information integration problem which may be eased if semantic technologies are used to find content relating to the same instances, enabling mappings between different ontologies created by experts to be re-used by all aggregators.

Mediating and creating communities

A wave of individualization and democratization of the Internet is connected to the term Web 2.0 (also called “social software”), which promotes user participation. Examples of this social phenomenon are social networks such as myspace.com and friendster.com, but also personal Web blogs and the contribution to common content management platforms such as Wikis. In all cases the social phenomenon is based on increased and simplified user participation:

  • In social networks it is easy to discover new friends and easy to express characteristics about oneself or opinions about others.
  • In WebLogs or “Blogs” the creation of online content has been simplified to textboxes and submit buttons, abstracting from the tedious content creation process incorporating the writing of HTML files and the uploading of data to a Web server.
  • In Wikis, a simplified mark-up syntax enables one to easily interlink several documents.

Again, problems of scale occur which require the use of additional intelligence to be solved.

Consensus building mechanisms

One of the gravitational principles of Web 2.0 is that we can see the Web as a platform (see What is the Web 2.0? Design Patterns and Business Models for the Next Generation of Software, by Tim O'Reilly). Going from the ‘traditional’ Web (now referred back to as Web 1.0) to the current Web 2.0 has changed the way which we perceive and interact with the Web and its content. The Web 1.0 publishing mechanism was very clear: it was conceptually designed for the publication, once and for all, of static documents by publishers for readers. Consequently there were few opportunities for feedback and even less for consensus, both using other Internet technologies such as email with the Webmaster. With the advent of Web 2.0, the style of communication has changed completely and there now exists a broad two way channel. Moreover, each resource in the Web is a vehicle for community interaction. There now exist examples in Web 2.0 where this paradigm has been pushed to the extreme – Wikipedia being the best known – such that the entire content is achieved by consensus.

In a transactional electronic world whenever a service fails it is obliged to undo previous atomic actions, in order to ensure that no undesirable side-effect remains. Compensation, substitution and agreement are terms from human interactions being captured and applied in automated business processes.

Some online marketplaces – for instance the academic site Kashba, or the commercial sites onSale and eBay – introduce collaborative reputation mechanisms to help users evaluate risks associated with a transaction based on the reputation of other parties. If a partner fails to fulfil an agreement, the partner’s reputation is damaged and future transactions may be jeopardized. Users who are honest and fulfil their obligations enjoy an enhanced reputation and will be able to complete more transactions.

It is commonly known that humans trust people they know more, especially if they have known them for some time. The net of contacts around the Web is very dense and with the help of initiatives like FOAF, people are able to represent information about themselves, their friends and whom they trust. The use of technologies like FOAF in the field of services will allow software agents, and humans, to gain information on the reliability and reputation of a service. For example if a service I know and use (e.g. my flight booking service) has been combined successfully with a geographical location service, it is important that I am able to gain any information on the newly introduced service. In SOA4All we will investigate how Web 2.0 technologies can support trust and reputation within and between computers and humans.

 
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