The Ubiquitous Web

Ubiquitous. [adj]

(seemingly) present
everywhere simultaneously.
often encountered
[Latin ubique everywhere]

Oxford English Dictionary

Ubiquitous Computing

Ubiquitous computing represents a powerful shift in computation, where people live, work, and play in a seamlessly interweaving computing environment. Ubiquitous computing postulates a world where people are surrounded by computing devices and a computing infrastructure that supports us in everything we do.

Mark Weiser, The Computer of the 21st Century, Scientific American, Sept 1991.

Ambient Intelligence

Ambient Intelligence implies a seamless environment of computing, advanced networking technology and specific interfaces. It is aware of the specific characteristics of human presence and personalities, takes care of needs and is capable of responding intelligently to spoken or gestured indications of desire, and even can engage in intelligent dialogue. Ambient Intelligence should also be unobtrusive, often invisible: everywhere and yet in our consciousness — nowhere unless we need it. Interaction should be relaxing and enjoyable for the citizen, and not involve a steep learning curve.

EC Information Society Technologies Advisory Group, 2001.

Web Browser as Information Appliance

The Web browser has become an appliance for accessing all manner of information and services. It shrinks into the background in that users don't need to learn from scratch each time they visit a new web site. The browser is an application platform and avoids the need to install and manage new software each time you want to use a new application — you just point the browser at the website and you are off and running. For developers, markup and scripts are much easier than C++ and Java. Application developers are deserting Microsoft Windows for the Web.

New Roles for Web Browsers

Traditionally Web browsers have run on desktop computers connected to the Internet via LANs or modems
Cellphones have evolved to support data services and now include small web browsers
HTML is now being used for all kinds of applications
Markup and scripting doesn't have to be used for accessing the World Wide Web
- It can now be used for user interfaces for many kinds of local and remote capabilities, cutting development costs over traditional approaches to application development
- "Browsers" are now a generic user interface component

Trends

Increasing variety of devices being connected to networks, not just desktops and cell phones
First in offices, and now in homes
- Ubiquitous Open Platform Forum
  
  Tokyo, February 2004: 14 electric appliance companies working collectively to promote Internet accessible electrical appliances
Web applications need to encompass a much wider range of devices
- Cameras, copiers, scanners, printers, home appliances of all kinds, environmental sensors and effectors, specialized engines for speech, handwriting, etc.

Glass Walls

Things don't have to be the way they are
- Instant messaging and presence are handled through different software clients and protocols
- Voice calls versus data services
- Fixed user interfaces on devices
A more powerful framework for Web applications would enable the removal of these walls
The Ubiquitous Web is intended to do just that!

Ubiquitous Web

The Ubiquitous Web seeks to broaden the capabilities of browsers to enable new kinds of web applications, particularly those involving coordination with other devices. Some examples include connecting a camera phone to a nearby printer, using a cell phone to give a business presentation with a wireless projector, and viewing your mailbox while listening to your messages.

Ubiquitous Web

These applications involve identifying resources and managing them within the context of an application session. The resources can be remote as in a network printer and projector, or local, as in the estimated battery life, network signal strength, and audio volume level. The Ubiquitous Web will provide a framework for exposing device coordination capabilities to Web applications.

Device Coordination

Registering what services a device provides
- How to describe services
Discovering what services are available
- Could be local or remote
- May be physically nearby, but on different networks
Binding to a service
Using a service
Relinquishing a service
How to expose existing device coordination frameworks to Web applications?
- UPnP, WSD, Jini, Salutation, ...

Ubiquitous Web Requirements

Dynamically adapt to user preferences, device capabilities and environmental conditions
Extend device capabilities through access to resources available via the network
Respond to events over the network from servers and other devices
Enable applications involving multiple devices
Use events to coordinate voice and data to augment human to human conversations
Manage resources in terms of temporary and persistent sessions

Enabling Technologies

The Dynamic Properties Framework
IDL for describing interfaces for distributed systems and as used for the W3C DOM
- See next slide
URIs for naming resources, sessions and interfaces
Semantic Web for ontologies describing device capabilities
Web Services for passing commands and events
Existing device coordination mechanisms

The DOM and Distributed Services

Web application identifies need for a service
- e.g. speech synthesis and recognition
It discovers and binds the service
This exposes the service to the local DOM but hides the details of how it is implemented
- Local interface can be described in IDL and exploited via markup or scripting
For a remote speech engine, the local interface acts as a proxy for the speech engine
The implementation could make use of Web Services, based upon WSDL and SOAP

Discovery

How does discovery work?
First step is to describe what is needed
Next step is to search for matching resources
- Simple multicast query to nearby devices
- Unicast query to search engine (gateway or broker)
- Centralized versus peer to peer search mechanisms
The selected resource can then be bound for the duration of the session
The resource is exposed to
- Markup as an IDREF or URI that other markup can reference
- Scripting as an object with methods that application functions can call

Discovery

How does discovery work?
First step is to describe what is needed
Next step is to search for matching resources
- Simple multicast query to nearby devices
- Unicast query to search engine (gateway or broker)
- Centralized versus peer to peer search mechanisms
The selected resource can then be bound for the duration of the session
The resource is exposed to
- Markup as an IDREF or URI that other markup can reference
- Scripting as an object with methods that application functions can call

Universal Resource Identifiers

URIs for naming resources, sessions and interfaces
- Resources include devices, services, and media resources
  - Discovery of resources by name or type
  - Additional constraints, e.g. In the same room
- Sessions are temporary lasting for a few web pages, or persistent, and something an application can join and leave
- Querying for support for named interfaces
  - Component Object Model (COM) and QueryInterface method
  - Generalization to the Ubiquitous Web
    - Querying objects obtained via DPF or resource discovery
    - Interface names, IDL and the DOM
  - UUID's can be used as URI's
    - For instance, in XML descriptions for UPnP 1.0

Descriptions and Ontologies

Ontologies provide formal description of concepts and relationships
- W3C Web Ontology Language (OWL)
W3C Device Independence Working Group is looking at how OWL could be used for formal definitions of properties for use with DPF, DISelect and CC/PP
May be valuable for queries for resource discovery
- Descriptions of devices and services
- Additional constraints e.g. physical location
  - What devices are in the room we are meeting?

Role of Web Services

Like the DPF, the Ubiquitous Web hides the implementation from markup and scripts
- Simplifies application design
- Enables multiple implementations
Web Services can be used for messages to
- For services provided by networked devices
  - JavaScript object implemented in C++ or Java
  - Translate JavaScript method call into a SOAP message
  - Translate response message into a DOM event
- Access and update remote properties
  - As described for the DPF
- Join and leave a persistent session

Universal Plug and Play (UPnP)

Well established for attaching peripherals to a Personal Computer
Provides mechanism for devices to get an IP address and to register a description of the device and the services it provides
- XML description of name, model and vendor
- URIs used for identifying services and devices
- Used to bind to matching device driver
Discovery mechanism using multicast queries for devices on local connection, or via broker for devices that are further away
Suffers from weak description language and limited query mechanism

WS-Discovery

Essentially UPnP recast in terms of Web Services
- Part of Microsoft's plans for Longhorn
  - WinHEC'04 describes Web Services stack for devices called "Web Services for Devices"
Suffers from similar problems to UPnP
- Weak description language (details lacking)
- No support for rich queries over service descriptions
- No support for liveness info on services
- No support for Internet-scale discovery
- Difficulties in searching across heterogenous networks
  - Where devices use different network technologies such as Bluetooth, WiFi, Ethernet and GPRS

Next Steps

Plan to hold a W3C Workshop on the Ubiquitous Web in October 2005
- Date and location to be announced soon
An opportunity to share use cases, research results, and implementation experience
Consider possibility of launching a new W3C Working Group