A Web Service Based Architecture for Ubiquitous Computing Applications

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A Web Service Based Architecture for Ubiquitous
Computing Applications
Supervisor Dr. Md. Mostofa Akbar

• Imranul Hoque (9905010)
• Sonia Jahid (9905016)

Department of CSE, BUET
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• The most profound technologies are those that
  disappear. They weave themselves into the fabric
  of everyday life until they are indistinguishable
  from it.
• Mark Weiser, Xerox PARC,1991

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Topics

• Definition
• Motivation
• Problem Definition
• Research Contribution
• Evolution of Web Service
• Related Works (Gaia, Aura, One World)
• Prerequisite of the Architecture
• Architecture
• Analysis of Architecture
• Comparison
• User Scenario
• Design
• Future Works
• Conclusion

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Ubiquitous Computing

• Ubiquitous Computing is invisible, everywhere
  computing that does not sit on the desktop but
  lies deep inside the environment we live in.
• Ubiquitous or pervasive computing introduces the
  notion of one person, many computers as
  technologies weave themselves into the fabric of
  daily life.

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Major Trends in Computing

• Mainframe One Computer, many people
• PC One person, one computer
• Ubiquitous Computing One person, many computers
• Ubiquitous Computing introduces the age of
  calm technology, when technology recedes into the
  background of our lives.

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UbiComp Vs. Virtual Reality

• UbiComp is roughly the opposite of VR. Where VR
  puts people inside a computer-generated world,
  UbiComp forces the computer to live out here in
  the world with people.
• UbiComp is a very difficult integration of human
  factors, computer science, engineering, and
  social sciences.

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Motivation

• Human-centered computation
• Bringing computation to us instead of taking
  ourselves to the devices
• Natural communication using speech and gestures
  instead of typing, clicking learning computer
  jargons
• A great software engineering challenge.
• Sociologically, UbiComp may mean the decline of
  the computer addict
• Overcome the problem of information overload

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Problem Definition

• Building applications for ubiquitous computing
  environments introduces great challenge to the
  system designers and programmers. Lack of robust,
  scalable and interoperable architecture makes the
  task even harder.

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Research Contribution

• Study of various UbiComp architecture
• Propose a new architecture for UbiComp based on
  Web Service
• Comparison of different UbiComp Architectures
• Mapping a user scenario
• Future research work

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Background

• Evolution of Web Service
• Client-Server Architecture
• Common Object Request Broker Architecture (CORBA)
• Distributed Common Object Model (DCOM)
• Java RMI
• Message Oriented Middleware (MOM)
• Architecture for Ubiquitous Computing
• Gaia
• Aura
• One.World

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Evolution of Web Service
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Client-Server Architecture
An architectural model of a typical client server
system in which multiple desktop-based business
client applications access a central database
server.
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Client-Server Limitations

• Complex business processing at the client side
  demands robust client systems.
• Security is more difficult to implement
• Increased network bandwidth is needed
• Maintenance and upgrades of client applications
  are extremely difficult
• Suits mostly database-oriented standalone
  applications and not robust reusable
  component-oriented applications.

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CORBA
The architectural model of CORBA with an example
representation of applications written in C, C,
and Java providing IDL bindings.
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CORBA Limitations

• High initial investment
• Availability of CORBA services
• Scalability

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Java RMI
The architectural model of a Java RMI-based
application solution.
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Java RMI Limitation

• Limited to Java platform
• Achieving high scalability becomes a challenge.
• No specific session management support.

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Microsoft DCOM
Basic architectural model of Microsoft DCOM
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DCOM Limitation

• Platform lock-in
• State management
• Scalability
• Complex session management issues

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Message Oriented Middleware
A typical MOM-based architectural model
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MOM Challenges

• Most of the standard MOM implementations have
  provided native APIs for communication with their
  core infrastructure. This has affected the
  portability of applications across such
  implementations and has led to a specific vendor
  lock-in.
• The MOM messages used for integrating
  applications are usually based upon a proprietary
  message format without any standard compliance.

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Web Service

• a software application identified by a URI,
  whose interfaces and bindings are capable of
  being defined, described, and discovered as XML
  artifacts. A Web service supports direct
  interactions with other software agents using
  XML-based messages exchanged via Internet-based
  protocols
• W3C Consortium

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Web service More Specific

• a standardized way of integrating Web-based
  applications using the XML, SOAP, WSDL, and UDDI
  open standards over an Internet protocol
  backbone.
• XML is used to tag the data
• SOAP is used to transfer the data
• WSDL is used for describing the services
  available and
• UDDI is used for listing what services are
  available
• Web-o-pedia

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Web Services Basic Operational Model
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Architecture for UbiComp
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Gaia - Architecture
Architecture of Gaia
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Gaia - Architecture

• Gaia Kernel
• Gaia Application Framework
• Applications
• iCalendar - schedules appointments and tasks
• Attendance - records participants for a task
• MP3Player - plays music to various speaker
  devices
• PPTViewer - displays PowerPoint presentations on
  multiple displays
• TickerTape - scrolls information around the room
  displays
• Scribble - synchronizes drawing and sketching for
  brainstorming
• Clicky - A utility for controlling multiple
  devices through a handheld device, like a PDA or
  a mouse
• Poll Manager - Application for conducting a poll,
  and gathering results in real-time

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Gaia - Problems

• Too heavy
• CORBA
• Java RMI
• DCOM
• Co-operation between applications and services
  running on different implementation is difficult
• Gaia applications may not benefit from Web
  Services

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Aura - Architecture
Architecture of Aura
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AURA - Architecture

• Odyssey supports resource monitoring and
  application-aware adaptation.
• Coda provides support for nomadic, disconnect
  able, and bandwidth-adaptive file access.
• Spectra is an adaptive remote execution mechanism
  that uses context to decide how to best execute
  the remote call.
• Prism is a system layer that is responsible for
  capturing and managing user intent. It is layered
  above applications and provides high-level
  support for pro-activity and self-tuning.

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Aura - Architecture
Prism Architecture
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Prism - Architecture

• Task Manager, embodies the concept of personal
  Aura.
• Context Observer provides information on the
  physical context and reports relevant events in
  the physical context back to Prism and the
  Environment Manager.
• Environment Manager embodies the gateway to the
  environment.
• Suppliers provide the abstract services that
  tasks are composed of text editing, video
  playing, etc.

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Aura - scenario
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Aura - Problems

• Ongoing project Many details are still very
  vague
• Prism is built on RPC and CORBA
• Current research focuses on the case of a single
  user

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One.World - Architecture
Architecture of One.World
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One.World Foundation Services

• Virtual Machine
• Provides a common execution environment across
  all devices and hardware platforms
• Tuples
• Define a common data model for all applications
  and thus make it easy to share data
• Asynchronous Events
• Make change explicit to applications instead of
  forcing users to manually reconfigure their
  devices
• Environments
• Serve as containers for stored tuples,
  application components, and other environments

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One.World System Services
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One.World - Problems

• Built on Virtual Machine JVM / MS CLR
• Tuple based XML is much better solution
• Implements tuples through Java classes Program
  everything into code
• Own networking protocols impossible to integrate
• Communication through Asynchronous Events What
  about Image Data/ Video Stream

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Overall Problems

• Absence of Unique Architecture
• Based on CORBA/RPC/RMI/DCOM
• Interoperability

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New Architecture
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Prerequisites of an Architecture

• Device and Service Description
• Discovery
• Communication
• Inter-operability
• Service Composition
• Security
• Adaptability
• Scalability

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Pseudo Solution

• Solution by Simple Modification
• Central Middleware
• Point to Point Communication

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Central Middleware

• Introduce a centralized middleware controlled by
  a third party, but problem

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P2P Communication

• Separately tacking the integration problem with
  each of the partners, but problem

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New Web Service based Architecture
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Proposed Architecture

• Creates another level of abstraction over the
  current Architectures
• New UbiComp applications can be built from
  scratch also
• Divided into two parts
• Internal Architecture expose internal operations
• External Architecture integrate different
  architectures

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Internal Architecture

• Another tier on top of the other tiers of the EA
• Conventional Middle ware is used to build
  multi-tier architectures
• Applications are hidden behind service
  abstractions
• The middle ware used at each level need not be
  the same
• Middleware simply acts as the glue

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Internal Architecture
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External Architecture

• Centralized brokers
• Name and Directory Services UDDI
• Protocol infrastructure
• Communication Protocol SOAP
• Service composition infrastructure
• Definition and Execution WSDL

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Design Features

• Inter-operability
• Simplicity
• Dynamic Discovery
• Integration with WWW
• Security
• Scalability and Extensibility
• Lightweight

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Comparison
Proposed Architecture One.World Gaia Aura
Underpinning Technology Web Services Virtual Machine Distributed Object Systems Distributed Object Systems
Service Description WSDL Tuples XML, OWL XML, ADL
Service Discovery UDDI Proprietary Protocol Presence Service, Space Repository Environment Manager (JINI or Salutation)
Comm. SOAP Asynchronous Events Events, RPC RPC
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Comparison
Architecture Features Propose Architecture One.World Gaia Aura
Service Management Edit, Categorize, Sort, Filter, Create, Delete, Enable, Disable, Change etc. N/A Register, Manage and Control etc. Task Manager
Interoperability Excellent Limited Moderate Moderate
Security Excellent Limited Limited Limited
Resource Usage Low High High High
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User Scenario
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Use Case
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Important Services

• Location Service
• Neighbor Service
• Map Point Service
• Hotel Reception Service
• Hotel Room Service
• Available Resource Service
• Entertainment Service

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Class Diagram
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Sequence Diagram Get to Hotel
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Sequence Diagram Get Room
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Sequence Diagram Get Service
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Sequence Diagram Neighbor Service
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Future Works

• Architecture, Design Implementation
• File Server Content Delivery Network
• Security XML Encryption, XML Signature
• Semantic Web Intelligent Service Discovery

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Conclusion

• Analysis of Gaia, Aura, One.World
• Prerequisites of Architecture
• New Web Service based Architecture
• Critical Evaluation of Architecture
• User Scenario to Architecture Mapping
• Scope for future work

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Thank You

• http//www.imranul.com/publication/thesis.pdf
• imranul_at_gmail.com
• soniajahid_at_gmail.com