1. Architectural Issues in C-A Mobile Apps. Andrés Fortier 1,2, Cecilia Challiol 1, Gustavo Rossi 1,3, Silvia Gordillo 1,4 {andres, ceciliac, gustavo, gordillo}@lifia.info.unlp.edu.ar Context Aware Group 1 LIFIA, Facultad de Informática,UNLP. La Plata, Argentina. 2 DSIC, Universidad Politécnica de Valencia. Valencia, España. 3 CONICET. 4 CICPBA.

2. Outline Motivation. Architecture Outline. Current work. Conclusions. Further work.

3. Motivation: Physical Hypermedia Physical Hypermedia (P.H.) applications are a particular kind of context-aware, mobile systems. P.H. aim is to enhance real world objects with digital information and links. Objects in a P.H. application can be visited in two ways: Digitally. Physically.

4. Physical Hypermedia

5. Let’s suppose that the user is in front of La Plata Cathedral.

6. Digital Navigation Digital links are conventional hypermedia links, whose target is another Point of Interest or a pure digital node.

7. Digital Navigation Even though the user navigate digitally, he is still standing in front of the same physical object.

8. Physical Navigation When the user selects a physical link expresses the intention to physically walk to the link’s target.

9. Physical Navigation The user arrives to the link’s target. At this moment the user finishes his current physical navigation.

10. Summary Physical Hypermedia is just an example of a Context- Aware Mobile application. Other examples are: Location based services. Context-Aware groupware tools. Augmented reality. Smart homes. Each domain has its own complexity.

11. Rationale behind the discussion We can’t predict all possible scenarios (context information, type of sensors, kind of adaptability, etc.). Therefore we aim to: Provide an integration platform, that is able to accommodate different requirements. Define basic concepts that are common to these applications. Provide a set of hotspots. Deliver frameworks that work inside the platform for the most common applications (e.g. LBS, PH, etc.).

12. Schema

13. Underlying Design and Architectural Decisions Application Model Aware Object Context Features

14. Extending an object with its context Application Model Context Model Aware Object Context Features

15. Extending an object with its context Office Scheduling System Context Model User Room Projector Location Temperature Notebook Noise level Activity

16. Extending an object with its context Office Scheduling System Context Model User Room Projector Location Temperature Notebook Noise level Activity Adaptation Environments (User) Location Based Services Smart Room Facilities

17. Handling Context Changes Finally each environment contains a set of handlers. A handle is triggered each time a context feature changes. Example: Smart room with different devices. Control room temperature. Room will have a temperature context feature. And a handler that is triggered every time it changes.

18. Handling Context Changes Office Scheduling System Room Projector Notebook Keep temperature between 18 and 22 degrees Celsius Context Model Location Temperature Noise level State Active Application H1 Turn off the lights when the projector is showing a presentation Smart Room Facilities Adaptation Environments H2

19. Architecture mappings in PH In the P.H. case we might not need an underlying model. We start by taking into an account the user location. Context Model Aware Object (User) Physical Location

20. Architecture mappings This location in turn has three representations Digital Network (i.e. Standard Hypermedia). Physical Network (i.e. Physical Places). Geometric Representation + City Information (i.e. City Map).

21. Architecture mappings To add P.H. behaviour we define a suitable environment. Context Model Aware Object (User) Physical Location Adaptation Environment Physical Hypermedia Environment City Cartography

22. Architecture mappings We also model the digital navigation as a context feature to be able to manipulate it. Remember that the user can navigate digitally while standing in the same physical place. With these two features, we can update the browser according to the user location changes.

23. Architecture mappings Context Model Aware Object (User) Physical Location Digital Navigation Browser as a View of the user’s context

24. Architecture mappings Context Model Aware Object (User) Physical Location Digital Navigation Adaptation Environment Physical Hypermedia Environment H1 H2 Handler for updating the digital navigation when the physical location changes. Handler for updating the digital navigation when the user clicks on a digital url

25. Current Work - Physical Backtracking Select a specific visited physical object using physical back and next functionality.

26. Current Work - Physical Backtracking Back to a specific physical object (visited objects) should be consider a new physical navigation. The user walks to reach the selected physical object.

27. General Conclusions Our thesis is that, by discovering the set of main concepts involved in context-dependent applications, we will be able to deliver a generic platform. This platform is a work in progress. As we develop new case studies, we refine the abstractions.