MIDAS – 10/27/2003
MIDASMIDASMulti-device Integrated Dynamic Activity SpacesMulti-device Integrated Dynamic Activity Spaces
Dissertation Proposal by
Unmil P. Karadkar
CSDL and Department of Computer Science
Texas A&M University
MIDAS – 10/27/2003
OutlineOutline
• The nature of Web-based services
• A need for change
• MIDAS – Architecture– Characteristics– Evaluation
• Research Contribution
• Work plan
MIDAS – 10/27/2003
Contemporary Web ServicesContemporary Web Services
• HTTP is server-centric– Session management– Information delivery
• Request-response architecture– Server only responds to the client
that requesting client
• All clients are treated at par– Personalization addresses user
characteristics, not those of the client device
request
response
MIDAS – 10/27/2003
Assumptions of Web ServicesAssumptions of Web Services
• All clients are, more or less, alike– Desktop computers– 800X600 or 1024X768 color displays– At least 56Kbps internet connection– Abundant processing power and storage space
• Desktop computers– Dominant when HTTP was designed– Located in secure home or office environments
MIDAS – 10/27/2003
Attack of the PhonesAttack of the Phones• Proliferation of mobile devices
– Notebook computers, PDAs, cell phones and pagers
• Diversity in characteristics of client devices– 96X96 to 1600X1200 pixel color or monochrome displays
– Processing and storage space crunch
– Connection speeds vary
• Diversity in characteristics of the environment– Private or secure locations (homes and offices)
– Semi-private locations (cars)
– Public locations (airports, hotel lobbies, malls)
MIDAS – 10/27/2003
Serving mobile and desktop devices Serving mobile and desktop devices
Services
HTTP
Datastore
ServicesWAP
• Remodeling of existing services– Little consideration for context or environment
• All mobile devices are treated at par
• Alerts are specific to a device– What if the device was unavailable?
MIDAS – 10/27/2003
Building device communitiesBuilding device communities• People typically carry more than one device
– Notebook, cell phone, PDA, pagers
• Different devices have different strengths– Cell phones—audio, PDAs—video, text
• Integration of these devices– Reduces reliance on any one device (redundancy)– Provides options for delivering information– Help deliver information that none of the devices
can render by themselves (co-use)
MIDAS – 10/27/2003
Power to the clientsPower to the clients
• Client devices have better knowledge of– Their own capabilities
• Display, storage, connection
– Their location• GPS helps pinpoint device location
• The location can be mapped to a physical spaces
• Characteristics of physical spaces can be determined
– User activity
MIDAS – 10/27/2003
MIDASMIDAS
Multi-device Integrated Dynamic Activity Spaces
MIDAS – 10/27/2003
MIDAS - ArchitectureMIDAS - Architecture
Users
Hypertext Authoring
Tool
Hypertext Specification
Information Service
Device 3Device 2
Device 1
Browser 4Browser 3
Browser 2
AuthorsThe WebTrellis and caT
Browser 1
MIDAS – 10/27/2003
Device 3Device 2
Device 1
Browser 4Browser 3
Browser 2
MIDAS - ArchitectureMIDAS - Architecture
Authors
Users
MIDAS
Device Manager
user and device profiles, current device load
resource handles,author preferences
user actions
Browser 1
Select Device(s)
status,user actions
Browser Coordinator
Browser registry
user actionsinformation content
Hypertext Authoring
Tool
Hypertext Specification
Information Service
resource handles, constraints, preferences
information content, resource properties
Resource Realizer
Resource Repository
resource instance(s)
resource handle, constraints
Resource Author
Authors
MIDAS – 10/27/2003
MIDAS - CharacteristicsMIDAS - Characteristics• Will extend the caT system• Information service interacts with the virtual device
symbolized by the Device Manager• The Device Manager decides where and how to render
every information element based on– Available devices– User and/or author preferences
• Every device presents information in a format that it can support
• Intrinsically supports– Accessibility– Internationalization
MIDAS – 10/27/2003
Attributes that affect browsingAttributes that affect browsing• Device
– Display (resolution and colors)– Storage space– Processor speed– Bandwidth
• User– Expertise– Media, device and other
preferences– Access privileges
• Environment– Privacy– Security– Interference
• Information elements– Media (mime) type
– File size
– Version
– Creator
– Creation timestamp
– Location
– Textual description
– Required display space
– Display colors
– Required bandwidth
– Language
– Priority
– Privacy
MIDAS – 10/27/2003
MIDAS - IssuesMIDAS - Issues• Authoring strategies for optimal coverage of devices
with minimal effort
• Defining policies– Device Manager—choosing devices – Browser Coordinator—choosing browsers– Resource Realizer—returning the “best possible” resource
• User Interaction: interfaces to– Indicate their preferred devices for a variety of conditions– Override system choices– Include third party or public access devices in the device space
• Interaction with the public devices in a user’s space
MIDAS – 10/27/2003
MIDAS - EvaluationMIDAS - Evaluation• Evaluation with simulated rather than real devices
– Configurable for a wide variety of devices– Will facilitate testing without incurring the expenditure
• Criteria– Completeness – all information is presented– Validity – each information element satisfies all user and
system constraints– Coherence – the individual elements do not conflict with
others (simultaneous rendering of audio/video elements on different devices) – Comprehension – the user can understand and use the
presented information
• Other details still being worked out
MIDAS – 10/27/2003
MIDAS – Research ContributionsMIDAS – Research Contributions• An architecture that
– Adapts presentation in response to user, device, environment characteristics
– Supports dynamic inclusion and exclusion of devices– Uses multiple devices in tandem for the presentation– Facilitates user interaction from any or all devices– Integrates included devices into a single virtual device– Supports opportunistic inclusion of other appliances– Allows authors to specify the elements that must be
presented faithfully
• An operational system that implements this architecture
MIDAS – 10/27/2003
MIDAS – Research ContributionsMIDAS – Research Contributions
• Identification of issues in – Information presentation to a set of devices– Simultaneous presentation of multiple audio-video
elements – Minimizing authors’ efforts while ensuring that
their hypertexts can be rendered on the widest possible range of devices
• A satisficing resolution of these issues
MIDAS – 10/27/2003
MIDAS – Work PlanMIDAS – Work Plan• Modify existing caT server-side components
– Include necessary features in xTed and the caT server
• Design and develop MIDAS components– Device Manager– Browser Coordinator– Resource Realizer (authoring and delivery)
• Modify caT browsers or develop new browers• Design communication protocols between
– caT server and Device Manager– Device Manager and Browser Coordinators– Browser Coordinators and Browsers– Browser Coordinators and Resource Realizer
MIDAS – 10/27/2003
MIDAS – Work PlanMIDAS – Work Plan
• Design policies for– Selecting devices for serving resources– Choosing the optimal data formats for resources– Resolving conflicts between author and user
preferences– Inclusion of public-access devices
• Evaluate MIDAS
• Write Dissertation
MIDAS – 10/27/2003
Questions?
MIDAS – 10/27/2003
Related WorkRelated Work• SMIL• Capability-based information delivery
– Digestor and Pythia (1996, 1997)• Use of proxy-based customization of Web content• Unintended consequences due to automated conversions
– WebSplitter (parts of Web pages are delivered to devices)– Power browser (summarizes Web forms for mobile users)
• Document Specification– Multivalent documents (High processing and network transfer costs)
• Multi-device information access– MMUI (Multi-Machine User Interfaces)– Windows-specific– Use of PDAs for input and display extension
MIDAS – 10/27/2003
TrellisTrellis• A hypertext system based on colored, timed
Petri nets– defines document structure using Petri nets– supports browsing semantics of hypertext documents
based on the Petri net state– has a distributed client/server architecture
• Adaptation of presentation– server side (WWW)– client side (Trellis, caT)– coordinated between the server and clients (MIDAS)
MIDAS – 10/27/2003
Trellis Trellis hypertext systemhypertext system• Based on colored, timed Petri nets• Supports
– specification of structure and browsing semantics of hypertext documents
– Analysis of authored hypertext structures
– specification of access control
– time-based hypertext browsing
• Separates– content from structure
– presentation from content
MIDAS – 10/27/2003
Examples of Petri netsExamples of Petri nets
MIDAS – 10/27/2003
caTcaT
• Incorporates context-awareness in Trellis
• Provides for basic user modeling
• Structured tokens contain dynamic and environmentally changing data
• Transitions may contain conditional statements
• Hierarchical nets to simplify authoring of large nets
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