A "single authoring" programming model: the interaction logic

For the mobile Internet, new content and applications are developed with the intent of delivering it through many different channels with different characteristics. Therefore, such content and applications must be adapted and optimized to each channel. Also, since new devices and content emerge continuously, this adaptation must be made to work for new devices not originally envisioned. In addition, it is important to be able to adapt existing content that may not have been created with this multi-channel or multi-modal deployment model in mind. Today, multi-channel applications are often repeatedly authored once for each channel. These multiple authoring methodologies can be classified as follows: repeated authoring of the application for each target channel; or repeated authoring of style sheets that enable transformation of a common XML representation. Under some constrained conditions, it is possible to automate the transformation of legacy or newly developed applications to multiple channels. It should be clear that it is in general impossible to automate the adaptation of legacy applications. Single authoring is motivated by the need to author, maintain, and revise content for delivery to an ever-increasing range of end-user devices