	Presentation Structure	Media Content	Layout	Style Properties
Discourse	Reflects the intended message of the author, organized in such a way it logically make sense.	A media item has a role within a presentation. Certain media items are more suited to be used within an introduction, others provide detailed information	If the document structure is relatively flat, discourse relations need to be expressed explicitly. For example an image, and a text explaining the image are next to each other and aligned to convey the relationship.	
Document Structure	Partly the structure of a blob of information is determined by the inherit structure of the document and the output media. For example a report has a particular document structure which is different to the structure of an essay.	The document structure (and presentation media) influence the media choice since they may not support the modality of the media item.	If the document structure is report the layout typically has chapters, sections subsections etc.	A scientific paper/report has a formal/serious lay-out. A powerpoint presentation typically is more colourfull.
Output Media	influences the structure of a presentation. A paper media has no temporal dimension, material can be presented spatially only. Within a film however the temporal structure is dominan			
Modality		The modalities available for presentation restrict the set of available media items.		
Genre		The genre influences the media choice. A biography/documentary document might use a painting of the subject. For a more formal document such as a CV a picture might be preferred.		Children stories typically have bright colours. Thrillers are black.
Style Properties		The color scheme of a presentation should match the media content.		
Domain	Presentation Structure defines roughly the organization of content to convey a particular message. To make decisions about what information needs to be presented together you might need information about the domain. Topia in contrast doesn't need this since the hierarchical grouping is determined by common attributes (independent of the domain). Disc knows about painters and artists en knows what is relevant information and how to structure it.	To select a particular media item you need to know what you want and how it is described by its metadata.		
Device	The device influences what media can be used, and by doing so influences the presentation structure	Selecting a media item only makes sense if it can be presented on the device you are using. Note that you might be able to adapt the media item to fit your requirement. Nevertheless this can be seen as just a larger collection of media items to choose from.	The layout should fit the display	do not use colours on black-white screens.
Media Content			Media items influence the style because of its content. (black-white photograph - abstract art)	The style is influenced by the content. Darker images work better on a dark background.
User	The structure of the presentation is tailored to the request of the user. First of all, if the system responds to a query of the user, it should be answered. Secondly the presentation should know about a the background knowledge of the user in order to serve both a domain specialist and a novice.	A user might have preference for particular modalities, or requirement which exclude modalities. Do not show x-rays of a painting to a 12 year old.	Not too many items on a screen	Apply bright colours forchildren. Larger fonts for people with bad vision. User preference for certain colours or colourblindness.

2004-11-11T13:13:22