Filling the gap between users and objects: a multichannel interactive environment Davide Carboni, Gavino Paddeu, Stefano Sanna, Andrea Piras {dcarboni, gavino, gerda, CRS4 – Center for Advanced Studies, Research and Development in Sardinia WOA 2003 – Villasimius (Cagliari)

Environment in evolution  Mobile computing  Pervasive computing  Domotics  Wearable technologies

WOA 2003 – Villasimius (Cagliari) Problem  An application is available only on a kind of devices.  Often developers have to re- implement it in order to reach other devices. Expensive tasks in terms of money and time.

WOA 2003 – Villasimius (Cagliari) The simplest approach  It is not necessary to re-implement the logic of the application but only to change its user interfaces.

WOA 2003 – Villasimius (Cagliari) A solution: model-based user interfaces  A model is usually defined with a tool that generates a task model.  The task model is translated in text document written following an ad-hoc declarative language.  A processor parses the text and composes the user interface.

WOA 2003 – Villasimius (Cagliari) Another solution: based on Model- View-Control  Decompose the application logic in a set of models that are strictly bound to the data.  For each model, the designer can provide one or more user interfaces, the View-Control subsystem.

WOA 2003 – Villasimius (Cagliari) Our approach  Starting from the MVC.  The model is a set of objects.  Each model is analyzed for rendering the user interface according to the features of the target device.  MORE – Multichannel Object Renderer

WOA 2003 – Villasimius (Cagliari) Model translation  Create a container for the actual channel.  Detect fields and methods of the object model.  For each field: search the coupled widget if it exists, add it to container else add a link  For each method: add widget to container

WOA 2003 – Villasimius (Cagliari) Categorization of devices  Fat Client: the device can download and execute mobile code (desktop, notebooks, tablet-PCs).  Thin Client: the device can execute local code and can download/upload data (PDA, set-top box, programmable phone).  Web-like Client: the device is equipped with 3 rd party browser.

WOA 2003 – Villasimius (Cagliari) MORE architecture

WOA 2003 – Villasimius (Cagliari) An object model: personal agenda

WOA 2003 – Villasimius (Cagliari) Personal agenda on fat clients

WOA 2003 – Villasimius (Cagliari) User interface generation on fat clients  The output of the model translation is the user interface.  The actions performed on the user interface are directly forwarded to the object model.

WOA 2003 – Villasimius (Cagliari) User interface composition on thin clients  The model translation is performed on server side and produces an XML document.  On the device, a small application is installed. It receives the XML document, parses it and generates the user interface.  Three implementations of MORE: iTV, PDA and smartphone.

WOA 2003 – Villasimius (Cagliari) Personal agenda on thin clients

WOA 2003 – Villasimius (Cagliari) User interface on web-like clients  As for thin clients, the model translation produces an XML document.  A XSLT processor takes the XML document and a selected set of XSL style sheets and returns the mark-up document for the user browser.  The processing is server side.  Four implementations of MORE: “high-end” HTML, “low-end” HTML, WML and VoiceXML.

WOA 2003 – Villasimius (Cagliari) Personal agenda on “high-end” HTML browser

WOA 2003 – Villasimius (Cagliari) Personal agenda on WML browser

WOA 2003 – Villasimius (Cagliari) Pros  The object models are ready-to-use for each category of devices with an existing implementation of MORE.  Easy to extend as new devices categories emerge.  Fast prototyping.

WOA 2003 – Villasimius (Cagliari) Cons  Limited customization of user interface.  Difficult access to peripherals connected to the user device.

WOA 2003 – Villasimius (Cagliari) Thanks for your attention Andrea Piras

WOA 2003 – Villasimius (Cagliari)

Why multichannel?  Multichannel because the 8 MORE implementations do not share the changes on an object and each one works as the others do not exist.

WOA 2003 – Villasimius (Cagliari) Updating the fields values  The value updates on the UI are update on the model too Directly on fat client Thin client sends a XML document Web-like client sends the values as parameters of the request

WOA 2003 – Villasimius (Cagliari) Result of an invoked method  If the result of the method is a complex object: it will be the next processed model a basic field: it will be encapsulated in a ad-hoc object and the object will be the next processed model null: the same object of the current UI will be the processed model

WOA 2003 – Villasimius (Cagliari)  The kind of the browser is identified analyzing the HTTP headers of the request. Standard user agent header for 3rd party browser Extended headers for thin client

WOA 2003 – Villasimius (Cagliari) MORE – agent?  MORE has the features of an intelligent agent: Capable of flexible action in some environment Reactive: responds to environment changes Proactiveness: attempt to achieve goals Social ability: can interact with other applications Veracity: communicate true information Benevolence: try to do what is asked Rationality: act in order to achieve goals