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

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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)

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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?

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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

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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

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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

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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

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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

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Examples of Petri netsExamples of Petri nets

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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