Volantis Systems Ltd. is one of the original members of the Device Independence Working Group. Volantis develops and supplies software that enables device independent authoring of web sites. For more than two years, Volantis has worked with a large number of customers in a variety of industries as they implement sites and applications that can be accessed from many different devices. As a consequence of a large number of implementations for dozens of customers, Volantis has accumulated a large amount of expertise in the practical implementation of such systems and in the characteristics of the devices that access them.
Volantis would like to contribute to the workshop by describing the principles that underly its approach to device independent authoring. These include a device independent markup language, based on XHTML, and mechanisms for capturing and using device dependent information for stylistic control, physical placement of material and use of media resources.
In addition, Volantis would like to contribute its practical experience to discussions on the topics suggested for inclusion in the workshop. In particular, Volantis has experience of how multi-device delivery affects interaction, navigation, visual and audio style, visual layout and the granularity of authoring units. It also has expertise in the use of CSS and XSLT style sheets in multi-device environments, of device independent authoring languages, and of many techniques associated with minimising the authoring effort associated with developing multi-device sites.
Volantis' Mariner product family is based on a number of principles that have proven themselves in the practical implementation of a large number of web sites and applications. Sites built using these principles can acccessed by devices that include a large number of WAP and i-mode mobile phones, various digital television systems, a wide range of Personal Digital Assistant's, personal computers, workstations and even systems that use voice as the only modality.
Volantis will describe a number of the fundamental principles on which their approach to device independence is based. Key for authors is the device independent markup language, based on familiar standards and incorporating powerful functional abstractions. Additional abstractions are used for device dependent information, such as stylistic specifications and data concerning the physical placement of presentation elements. These abstractions are organised in ways that allow authoring costs to be managed. Definitions can be reused and shared where appropriate, without compromising the ability to provide highly customised presentations where desired. The adaptation mechanism employs these abstractions together with delivery context. The delivery context includes information taken from a device repository in addition to information transmitted by the device itself. The adaptation process encapsulates device and user agent expertise, reducing the need for authors to be experts in the capabilities of the devices being supported.