Fillingthegapbetweenusersandobjectsamultichannel填充用户和对象的多通道之间的差距.ppt

1、Filling the gap between users and objects: a multichannel interactive environment,Davide Carboni, Gavino Paddeu, Stefano Sanna, Andrea Piras dcarboni, gavino, gerda, pirascrs4.it CRS4 Center for Advanced Studies, Research and Development in Sardinia,WOA 2003 Villasimius (Cagliari),WOA 2003 Villasimi

2、us (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

3、 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 gener

4、ates 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 mo

5、dels 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 accor

6、ding 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 ad

7、d 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, pro

8、grammable phone). Web-like Client: the device is equipped with 3rd 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 int

9、erface 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

10、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 (

11、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

12、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 w

13、ith 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 atten

14、tion Andrea Piras pirascrs4.it,WOA 2003 Villasimius (Cagliari),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 va

15、lues,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 t

16、he 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 en