Component-based Computing implications for Application Architectures

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Component-based Computing implications for
Application Architectures

• Julie A. McCann
• Imperial College, Department of Computing
• London UK
• jamm_at_doc.ic.ac.uk
• www.doc.ic.ac.uk/jamm

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Getting to the 3rd Wave

• What is the future of computing?
• pervasive computing?
• What is the fundamental requirements of such
  systems?
• How are we getting there?
• Go!
• Hypatia
• Go! Hypatia Jeffs ADLs ANS!

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Phase I
To the 3rd wave.
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Ubiquitous Computing?

• Mobile Computing ! Ubi
• Nano Computing ! Ubi
• What is it then?
• Involves many disciplines.
• Inspired by the social scientists, philosophers,
  and anthropologists
• paradigm shift?
• currently we expect the user to find ways to use
  the computer
• however we currently do not emphasise how the
  computer can find its own way to serve the user
• focus on HCI
• focus on security, privacy --gt big brother?

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pervasive computing

• What is pervasive computing
• Current technology
• Mobile computing
• Context adaptation
• Intelligent environment
• Adaptive architecture
• Security, privacy and management

Thanks to M. Sloman for slides
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What is Pervasive Computing?

• Technology View
• Computers everywhere embedded into fridges,
  washing machines, door locks, cars, furniture,
  people
• ? intelligent environment
• Mobile portable computing devices
• Wireless communication seamless mobile/fixed
• User View
• Invisible implicit interaction with your
  environment
• Augmenting human abilities in context of tasks
• Ubiquitous mobile computing intelligent
  environment

Thanks to M. Sloman for slides
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Mobility

• Mobile computing
• Computing communication on the move
• Mostly voice based or embedded?
• Nomadic computing
• Intermittent connectivity
• Usual environment available
• Mobile agents
• Mobile code and data

Thanks to M. Sloman for slides
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Contents

• What is pervasive computing
• Current technology
• Current near term gadgets
• Wearable computing
• Mobile computing
• Context adaptation
• Intelligent environment
• Adaptive architecture
• Security, privacy and management

Thanks to M. Sloman for slides
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Current Technology
Thanks to M. Sloman for slides
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Current Technology 2
Thanks to M. Sloman for slides
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Wearable Computers
Watch phone
Watch camera
Thanks to M. Sloman for slides
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Wearable I/O
Thanks to M. Sloman for slides
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Designer Gear
Thanks to M. Sloman for slides
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Wearable or luggable?
See http//wearables.www.media.mit.edu/projects/w
earables/mithril/index.html
Thanks to M. Sloman for slides
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The Whisperer

• Convert audio signals to vibrations sent via
  finger
• Send commands by tapping fingers in various
  rhythms

Thanks to M. Sloman for slides
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Usability

• Common user interface for workstation and mobile
  device applications
• Adaptive information display
• Replicate characteristics of paper-based
  notebooks for annotatablity, robustness,
  universality
• Flexible voice based input-output
• Voice recognition text to speech conversion
• Gesture recognition
• WAP phone is not a useable computing device!!
• Remove human from loop intelligent agents?

Thanks to M. Sloman for slides
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Brainwaves!
Thanks to M. Sloman for slides
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Contents

• What is pervasive computing
• Current technology
• Mobile computing
• Issues
• Wireless communication
• Ad-hoc networking
• Context adaptation
• Intelligent environment
• Adaptive architecture
• Security, privacy and management

Thanks to M. Sloman for slides
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Mobile Computing Vision

• Universal connectivity anywhere, anytime
• Accommodate heterogeneity of networks and
  communicators
• Ubiquitous intelligent environment embedded
  computers everywhere
• Easy user interaction
• Context independent access to services context
  dependent information

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Mobility Issues

• How to integrate mobile communicators into
  complex information infrastructures?
• What effect will they have on work and leisure?
• Privacy
• How to develop and manage adaptable,
  context-aware software systems?
• What support is needed within the network?

Thanks to M. Sloman for slides
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Wireless Communication

• GSM phone 9.6 Kbps
• Wireless LAN IEEE 802.11b 200 m range 2.4 Ghz
  band 11 Mbps
• Bluetooth 10 m range 2.4 Ghz band 1 data (700
  kbps) 3 voice channels
• UMTS 3G mobile114 kbps (vehicle), 384 Kbps
  (pedestrian), 2 Mbps (stationary)
• HIPERLAN IEEE 802.11a5 Ghz band currently 20
  Mbps eventually 54 Mbps
• HomeRF derived from DECT10Mbps
• InfraRed direct line of sight 4Mbs

Thanks to M. Sloman for slides
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Wireless Problems

• Too many similar standards
• Shortage of spectrum Use low power multiple
  base stations with intelligent antenna.
• Overlapping spectrum usage can cause
  interferenceeg Bluetooth and IEEE 802.11
• Unregulated bands lead to chaos
• Health risks?

Thanks to M. Sloman for slides
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Ad-hoc networking

• Networking with no fixed infrastructure
• Use other devices as routers
• But, security concerns and usage of scarce
  battery power for relaying possibly more suited
  to sensor than user networks
• See http//tonnant.itd.nrl.navy.mil/manet/manet_ho
  me.html

Thanks to M. Sloman for slides
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Ad-hoc Network Applications

• Military battlefield
• Disaster teams
• Autonomous robots eg searching buildings, mapping
  toxic spills
• Meetings exchange visiting cards and
  information
• Car trains on motorways 100 KmPH, 2m
  apartautomatic steering and braking

Thanks to M. Sloman for slides
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Ad-hoc Collaborative Working

• Support for cooperative working
• Group management protocols
• Public and private groups
• Service discovery
• Dynamic adaptation to other device interfaces

Thanks to M. Sloman for slides
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Integration of Mobile Systems

• Not stand alone devices.
• Need to interact with complex legacy information
  systems eg large databases merging updates,
  displaying tables etc.
• Systems development
• Requirements specification for adaptable systems
• Component composition to meet global QoS,
  security, reliability performance requirements.
• Mobility models
• Behaviour specification and analysis
• Modelling context aware systems
• Interaction paradigms
• Event-based not object invocation or RPC

Thanks to M. Sloman for slides
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Contents

• What is pervasive computing
• Current technology
• Mobile computing
• Context adaptation
• Intelligent environment
• Adaptive architecure
• Security, privacy and management

Thanks to M. Sloman for slides
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Context Awareness

• Context defined by
• Current location Need location detection eg GPS
  or base stationIndoors radio beacon, IR
• User activityWalking, driving a car, running for
  a bus how to detect this?
• Ambient environmentIn theatre, alone, in
  meetingLocal resources or services available
• Device capabilitiesScreen, input, processing
  power, battery life .
• Current QoS availability particularly for radio
  links

Thanks to M. Sloman for slides
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Context Adaptation
Server

• What Compression, filtering, device-specific
  transformations, information selection ..
• Where Server, proxy or client?
• Proxy ? client and server do not change
• See Armando Fox work at Stanford
• http//gunpowder.stanford.edu/fox/research.html

Proxy
Thanks to M. Sloman for slides
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User Selection

• Ultimately, users know best
• proxy transforms as best as it can, but gives
  users a way to force proxy to deliver original
  content
• here, a simple client-side UI enhancement is
  coupled with proxy-side refinement intelligence

refined content from Proxy
transformed content from Proxy
local UI interaction
From presentation by Armando Fox, Stanford
Thanks to M. Sloman for slides
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Map Adaptation
Rich dynamic data, Structured data metadata
User context based selection,Activity deadlines

• Elements river, road, motorway, buildings
• Variants scale, feature detail, date
• Dynamic data road conditions, weather

Thanks to M. Sloman for slides
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Adapting Vector Maps

• Maps can be
• Split into features and presented in part
• Encoded at different scales different feature
  detail
• Selective adaptation can consider content being
  degraded
• See http//www.doc.ic.ac.uk/dc/

Thanks to M. Sloman for slides
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Mobile MedicineHealthcare Everywhere

• Applications
• Automated monitoring
• Implanted devices
• Smart clothing
• Swallow/inject intelligent sensors and actuators
• Accident and emergency support
• Patient record access and integration

• Benefits
• High ?lower risk monitoring
• Mobility for chronically ill
• Greater out-of-hospital patient management
• Mass data analysis

Thanks to M. Sloman for slides
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Contents

• What is pervasive computing
• Current technology
• Mobile computing
• Context adaptation
• Intelligent environment
• Adaptive architecture
• Security, privacy and management

Thanks to M. Sloman for slides
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Smart Dust

• Autonomous sensing and communication in a cubic
  millimeter dust motes
• Sensors for temperature, humidity, light, motion
  .With bidirectional radio or laser battery
• Costs soon lt 1
• Typical Applications
• Defense related battlefield sensors, motion
  detectors etc.
• Inventry control on boxes which communicate with
  crates, trucks, plane etc to tell you where they
  are
• Product quality monitoring vibration, humidity,
  overheating
• Car component monitoring
• See http//robotics.eecs.berkeley.edu/pister/Smar
  tDust/

Thanks to M. Sloman for slides
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Smart Dust Technology
Passive laser reflector
Sensor
Near future
Current state 1999
Thanks to M. Sloman for slides
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Future Smart Dust

• Intelligent paper with integrated radio ?
  replace current displays
• Smart paint monitors vibrations and detect
  intruders or changes colour to react to
  temperature, lighting etc.
• Intelligent glass can filter sunlight, become
  opaque ? no need for curtains
• Smart garments or injectable sensors for people
  monitoring
• Download design and printable motes for lt 1c
  motewww.media.mit.edu/nanomedia
• Printable batterieshttp//www.usatoday.com/life/c
  yber/tech/review/2001-02-12-batteries.htm

Thanks to M. Sloman for slides
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Pervasive Computer Problems

• What means of communication?
• Radio spectrum shortage
• Light based very directional
• Batteries would be impractical power source for
  100K processors per person. Solar cells are not
  suitable for all environments.
• Solar cells capacitors or rechargeable
  batteries?
• Power not speed is the key issue for future
  processor designs.

Thanks to M. Sloman for slides
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Scaling factors

• gt 100K computers per person
• Self organising and self configuring
• Coherent behaviour from vast numbers of
  unreliable sensors, actuators and comms. devices
• Need new techniques for interaction based on
  biological organisms
• Exponential Growth?

94,023 billions per mm2
By 2100
425,352,958,651, 200,000,000,000,000,000,000,000B
illions of computers
Thanks to M. Sloman for slides
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Intelligent Environment - 1

• Fridge and cupboards tracks consumption and
  reorder your groceries
• Your car computer reminds you to pick up your
  order on the way home when you are near the
  supermarket.

Thanks to M. Sloman for slides
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Intelligent Environment - 2

• Lights, air conditioning, TV automatically switch
  on and off when you enter or leave rooms
• Sit on your favourite chair and TV switches on to
  the program you usually watch at this time of the
  day
• Use communicator/pda for phone, remote control,
  keys payments, passport, health records,
  authenticator.
• Route input from virtual keyboard to nearest
  suitable display.
• Automatic detection of new items to control and
  physical layout in a room or office, using
  computer vision.

Thanks to M. Sloman for slides
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Vision Based Interaction
Presence Is anyone there? Location Where are
they? Identity Who are they? Activity What are
they doing?
Head tracking Gaze tracking Lip reading Face
recognition Facial expression
Hand tracking Hand gestures Arm gestures
From http//research.microsoft.com/easyliving/
Thanks to M. Sloman for slides
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Contents

• What is pervasive computing
• Current technology
• Mobile computing
• Intelligent environment
• Adaptive architecture
• Security, privacy and management

Thanks to M. Sloman for slides
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Adaptive Application Architecure
Remote Application Servers
Sensors
Local Network Intermediate Servers
Clients
Thanks to M. Sloman for slides
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Policy
Rule governing choices in behaviour of the system

• Derived from trust relationships, enterprise
  goals and Service level agreements
• Need to specify and modify policies without
  coding into automated agents
• Policies are persistent
• But can be dynamically modified
• ?Change system behaviour without modifying
  implementation not new functionality

Thanks to M. Sloman for slides
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Policy Based Adaptive Systems

• Authorisation policiesDerived from trust
  relationships to define what resources or
  services clients can access, what proxylets or
  code can be loaded into servers, or what code
  loaded into the client can do.
• Obligation PoliciesEvent-condition-action rules
  to trigger when to perform actions, what alarms
  to generate etc
• Ponder declarative object-oriented languagefor
  specifying policies.See http//www-dse.doc.ic.ac.
  uk/Research/policies/

Thanks to M. Sloman for slides
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Example Authorisation Policy
inst auth facilities subject guests target
gym pool action enter when time.between
(0900, 2100)
Thanks to M. Sloman for slides
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Obligation Policy

• Defines what actions a subject must do
• Subject based ? subject interprets policy and
  performs actions on targets
• Event triggered obligation
• Actions can be remote invocations or local
  scripts
• Can specify sequencing or concurrency of actions

Thanks to M. Sloman for slides
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Example Obligation Policy

• inst oblig heartmonitor
• subject s medicAgent
• on heartanomaly (symptom)
• action s.display (messages symptom)
  -gt send(alarm, symptom)
• target cardiacCentre

Thanks to M. Sloman for slides
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Roles

• Group of policies with a common subject
• Defines rights (authorisations) and duties
  (obligation)
• Position in organisation nurse, surgeon
• Mobile visitor roles in hotel or shopping mall
  policies which apply to mobile user in an
  environment
• Paramedic attending an accident

Thanks to M. Sloman for slides
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Contents

• What is pervasive computing
• Current technology
• Mobile computing
• Context adaptation
• Intelligent environment
• Adaptive architecture
• Security, privacy and management

Thanks to M. Sloman for slides
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Security

• Interactions cross multiple organisational
  boundaries
• Specification, analysis and integration for
  heterogeneous OS, databases, firewalls, routers
• Lessons from history
• Cell phones, IR garage doors, CATV decoders
• Everything worth hacking gets hacked
• Need for secure out of the box set up
• Identify friend or foe ? level of trust
• Small communicators, with confidential data, are
  easily lost or stolen biometric authentication
• Necessary security technology exists

Thanks to M. Sloman for slides
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Privacy

• Location service tracks movement to within
  metres(cf mobile phones but pay-as-you-go can be
  anonymous).
• Clearly indicate you are being sensed or recorded
  user control to stop recording or control
  distribution of information
• You are now predictable
• System can co-relate location, context and
  behaviour patterns
• Do you want employer, colleagues or insurance
  company to know you carry a medical monitor?
• Tension between authentication and anonymity
  business want to authenticate you for financial
  transactions and to provide personalized
  service cf web sites
• Constant spam of context dependent advertising

Thanks to M. Sloman for slides
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Management the nightmare!

• Huge, complex systems
• Billions of processors
• Multiple organisations
• Managing physical world, controlling sensors,
  actuators
• Humans will be in the way
• Errors propagate to bring down complete regions
• Hacker and virus paradise
• System propagates false information about
  individuals or organisation
• Complexity of s/w installation on a workstation
  or server how do you cope with billions?

Thanks to M. Sloman for slides
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Management Solutions
Policy

• Intelligent agents, mobile agents, policy
• QoS Management
• Fat pipes and large storage can convert media
  streams to short traffic bursts in core network
  but still needed for wireless links
• Adaptive self-management is the only answer
• Partitioned domains of responsibility
• Genetic algorithms may be suitable for long-term
  strategy but need more deterministic solutions
  for short term decision making
• Remove human from the loop

Thanks to M. Sloman for slides
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Conclusions

• Universal PDA/communicator
• Explosion in embedded sensors/actuators
• Context-aware intelligent environment
• Privacy will be a major issue
• Out of the box security
• Adaptive self-management is needed biological
  paradigms?

Thanks to M. Sloman for slides
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Phase II
What needs to change?
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Ubicomp requires

• Adaptive, lightweight, flexible systems
• Like plugging in a light-bulb
• elegantly be able to cope with one device
  disappearing and new (perhaps upgrades) devices
  entering the resource pool.
• change its characteristics to do many differing
  tasks on demand.
• reconfiguring dynamically, self-aware and aware
  of fellow components.
• overhead needs to be lightweight and perform well
  for such technologies to succeed
• no systems management (self management)
• Adaptive ?
• Biological ?

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Componentisation

• Componentisation
• Breaks down system into components
• Components are plugged-unplugged with (little or
  no) warning
• Component managers make decisions to change
  components to effect adaptability (using
  feedback/monitoring)
• Only components required are loaded -gt
  lightweightness
• 24X7 potential, graceful upgrade of system where
  we update component at a time.
• Requirements
• Components can be self-aware and autonomous,
  likewise system is self-aware
• Component architecture description model
  (provides component management intelligence)
• For performance reasons we need components to
  build the whole system (i.e. not just the
  middleware e.g. Corba)

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Adaptivity

• Examples of adaptivity
• Seti/consume model small devices sharing
  resources on demand (using up free
  processing/bandwidth)
• Robustness- component beginning to fail (hw/sw),
  manager brings up others to take its place
• Performance network bandwidth getting tight,
  change data encryption, change route to user. Etc
  etc
• We are looking at component language description,
  adaptivity and fine grained (i.e. OS level)
  componentisation.

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Phase III
Proofs of concept
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A Solution?

• support improved performance, configurability,
  flexibility, dynamism, software eng.
• should be decomposed and support relatively small
  components
• Kendra looked at adaptivity
• performance problems -gt course grained components
• low protection overheads should enable fine
  -grained protection without sacrificing
  performance
• Components highly adaptive/flexible systems
• fine-grained componentization
• paging waste --gt 1/2 n P bytes lost to
  fragmentation
• n number of domains, P page size(bytes)
• segmentation
• language independent

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Go! A Novel Operating System

• protection model (software-based instruction set
  reduction) using code scanning
• code sections scanned before the OS loads them to
  ensure no privileged instructions are contained.
• Components invoke services via an ORB
  (privileged)
• component management
• loads segment registers to effect a context
  switch
• uses thread migration rather than asynchronous
  messaging

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Go!
Client component call
Server component return

• ORB

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Go! Results

• GTE is Go!s proof of concept

• good results for other temporal and spatial
  comparisons

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Patia Adaptive Management System for Distributed
Webservers
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Objectives

• Build adaptive framework to support
  high-performance distributed webservers
• Distribution mechanisms
• Data placement
• Request scheduling

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PATIA
Web presentations can consist of many varying
media and technologies often running concurrently.
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Distributed Web Servers

• Client based distribution
• Request routed to particular server by client
  (requires apriority knowledge of set-up.
• DNS based distribution
• Resolve URL to IP address (stamped with TTL) sent
  to client
• Cached with client and name servers on route
• caching of information by name servers means any
  server changes cant be reflected (lowers
  adaptivity)
• short TTL doesnt work as most servers discard
  low TTLs

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Distributed Web Servers (cont)

• Dispatcher based distribution
• Network component of web server selects node
• Operates at lower level in protocol stack
  (advertises single virtual-IP address)
• Typically use round-robin to select server
  (replicated servers)
• Server based distribution
• Uses DNS to select server node
• Server then does redirection if necessary
  (overcoming the TTL problem)
• Poorer performance currently measured for this
  technique

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Other Distributed Web Servers

• Content based dispatcher distribution
• Webserver node chosen depends on the TYPE of
  request sent by client
• Caching dispatcher distribution
• Dispatcher is a cache
• DNS/Dispatcher-Server based distribution
• Cluster DNS selects dispatcher (based on
  proximity to client)
• Dispatcher select webserver node
• Webserver node can carry out redirects to other
  nodes

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Constraint ltrule_conditionalgt ltrule_selectiongt
ltrule_ conditional gt if
ltboolean_expressiongt then
ltaction_sequencegt
else lt action
_sequencegt
end_rule ltboolean_expressiongt ltresourcegt
ltstandard_boolean_expressiongt lt action _sequencegt
lt action gt "" lt action gt lt action gt
ltinstructiongt "(" ltparameter_sequencegt
")" ltparameter_sequencegt ltparametergt ","
ltparametergt ltinstructiongt BEST, SWITCH
etc.... ltresourcegt PROC_UTIL or BANDWIDTH
etc... ltstandard_boolean_expressiongt AND, OR,
NOT, lt, gt, etc.... rule_selection case
resource of set_expr "" lt action _
sequence gt else lt action _ sequence gt
end case_rule Figure 3 BNF format for
Adaptivity Rules in Patia
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Fire
Gawesh and Linxues lab
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ANS ubiquitous computing management

• mimics an ANS (the Autonomic Nervous System) of
  living creatures.
• However, we are unaware of the workings of the
  organic ANS because it functions in an
  involuntary, reflexive manner. E.g. heart beats
  faster.
• What is particular about the organic ANS is that
  it is
• flexible,
• constantly in operation
• happens in the background without our
  interference or knowledge of its mechanism.
• This is exactly what is needed to support the
  application of the intelligent home and medical
  applications where constant technical support is
  impossible.

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ANS cont.

• Essentially the organic ANS is our bodys
  resource manager
• likewise the Ubicomp ANS Manager becomes the a
  replacement operating system or virtual machine
• provides the systems ability configure and
  reconfigure itself under differing conditions and
  ever-changing environments. Further, such a
  system should provide the intelligence to
  optimise its operation through constant
  monitoring and tuning to achieve its goal.
•  we require the architecture to be composed from
  lightweight components that co-operate.
• The expected benefits from the research are a
  clear and quantifiable set of requirements and
  more importantly, technological solutions to the
  problem of running the highly complex systems
  needed for ubiquitous computing with little or no
  user intervention for system management and
  maintenance
• We believe that solving this problem is key to
  realizing the ubiquitous computing vision. CALM

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Open questions

• beginning to observe that our system behaves in a
  similar fashion to that of biological systems.
• with finer-grained systems there are lots of
  (tuning) variables, many feedback loops to drive
  the adaptivity etc.
• These questions show how exciting the area of
  ubiquitous computing is and will continue to be,
• and how it will continue to encompass many
  diverse computing (and non computing)
  disciplines.

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References

• CACM May 2000 vol43, no 5
• Intelligent Environment
• http//www.media.mit.edu/
• http//cooltown.hp.com/
• http//portolano.cs.washington.edu/
• http//www.firstmonday.dk/issues/issue4_9/odlyzko/
  
• Wearable Computers
• http//www.redwoodhouse.com/wearable/
• http//iswc.gatech.edu/archives.htm
• Wireless communications
• http//www.wirelessdevnet.com/
• Mobile computing
• http//computer.org/dsonline/
• http//www.mobileinfo.com
• http//www.comp.lancs.ac.uk/computing/research/mpg
  /most/