SelfConfiguration of Adaptive Ubiquitous Applications

1
Self-Configuration of Adaptive Ubiquitous
Applications

• Prof. Dr. Kurt Rothermel
• Dr. Christian Becker
• Marcus Handte

2
Outline

• Motivation
• Project Proposal
• Automatic Configuration
• Project Status
• Priority Programme Integration
• Summary

3
Motivation

• Ubiquitous Computing
• Distraction-free support for tasks
• Distributed applications
• Dynamic environments (mobility)
• ? Applications need to adapt
• A common approach
• Applications as compositions of
  services/components
• Application composition needs to be configured at
  runtime
• Manual composition by user/administrator/programme
  r not viable
• Composition must be automatic easy to program,
  administer and use

Universal Messenger
4
Project Proposal

• Research Goal
• A lightweight algorithm to configure and
  reconfigure applications in potentially
  resource-restricted environments taking into
  account the resulting costs and potential quality
  gains using a simple quality metric.
• Structure
• 3 phases
• Determine
• Adapt
• Evaluate
• 6 work packages
• 2 supportive
• 4 main packages

5
System Model

• Peer-to-Peer Approach
• Devices in communication range cooperate
• No supporting infrastructure required
• PCOM Component System
• Components with contractually specified
  dependencies towards other components and local
  resources
• Container provides runtime environment for
  components and manages local resources
• Container provides basic services (e.g., remote
  communication, device/component discovery)
• ? Applications as tree of component instances
  composed along dependencies

Application
Input
Output
Input
Output
Input
Output
6
Automatic Configuration
File System (Input)
PDA
PPT Control (Application)
CPU
5
MEM
10
CPU
100
Imager (Display)
MEM
100
Input
Output
DISP
1
Laptop
Local PPT (Output)
CPU
5
MEM
10
Remote PPT (Output)
CPU
5
DISP
CPU
300
1
MEM
10
MEM
200
DISP
1
Display
Display

• ? Composition that satisfies structural
  requirements (no unresolved dependencies) and
  resource requirements (no overloaded resources)

PPT Control (PDA)
PPT Control (PDA)
File System (Desktop)
Remote PPT (Laptop)
CPU
5
Local PPT (Desktop)
CPU
5
File System (Desktop)
CPU
5
MEM
10
MEM
10
MEM
10
DISP
1
Executable Configurations
Imager (Desktop)
Imager (Desktop)
Not Executable Configurations
Unsatisfiable resource requirement
7
Requirements on Automatic Configuration

• Completeness
• Frustrated users if configuration sometimes not
  successful
• Systematic search that finds a valid
  configuration eventually
• Efficiency
• Short configuration delays since users might wait
• Applicable for a broad range of environments
• Distribution
• Do not rely on powerful server for configuration
• Suitable for peer-based systems
• Resilience
• Deal with failures and mobility during
  configuration

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Approach

• Interpretation as Distributed Constraint
  Satisfaction Problem
• Given Set of variables (distributed across
  agents) with finite domains and constraints
  between variable assignments
• Find Valid variable assignment for all variables
  
• Adapted Asynchronous Backtracking (Yokoo et al.
  97)
• Distribution use available parallelism, no
  powerful device
• Dependency-directed reconsiders only
  assignments that can resolve a conflict (conflict
  locality)
• Extension for resilience integrated

9
Mapping to CSP

• Dependencies as variables
• Component instances as domains
• Resource and structural requirements as
  constraints
• Partial solution
• Introduction of pseudo value
• Constraints
• If instance is used, dependencies must be
  resolved
• If instance is not used, pseudo value must be
  selected
• Instances on container must not overload resources

Input
Output
10
Evaluation

• Simulation of binary tree with 12 components on 4
  containers
• 1-30 components that introduce resource
  conflicts, 1 solution
• 1 conflicting resource on each container (no
  conflict locality)

11
Project Status

• Main Work Packages
• WP2 Algorithm to determine one configuration in
  resource-restricted environments
• Problem interpretation and modified backtracking
  algorithm
• M. Handte, C. Becker, K. Rothermel Peer-based
  Automatic Configuration of Pervasive
  Applications, International Conference on
  Pervasive Services (ICPS) 2005, Santorini,
  Greece, 2005
• Extended version submitted to International
  Journal on Pervasive Computing and Communications
  (JPCC)
• WP3 Analysis of reconfiguration costs and
  algorithm to reconfigure executing applications
• Greedy optimization on top of backtracking
• Andreas Störzbach, Entwicklung und Evaluation
  eines Algorithmus zur Anpassung von Anwendungen
  in PCOM , Diplomarbeit, Universität Stuttgart,
  Fakultät Informatik, Elektrotechnik und
  Informationstechnik, 2005
• WP4 Analysis of quality properties and
  development of one simple metric
• Initial framework for quality integration
• Christian Schwegmann, Entwicklung eines
  Rahmenwerks zur Modellierung von
  Qualitätsmerkmalen für Konfigurationen in PCOM,
  Diplomarbeit, Universität Stuttgart, Fakultät
  Informatik, Elektrotechnik und Informationstechnik
  , 2005
• WP5 Integration of quality metric into
  algorithms for (re-)configuration
• Supportive Work Packages
• WP1 Further mechanisms to support dynamic
  execution environments
• M. Handte, G. Schiele, S. Urbanski and C. Becker
  Adaptation Support for Stateful Components in
  PCOM, Workshop on Software Architectures for
  Self-Organization Beyond Ad-Hoc Networking at
  Pervasive 2005 , München, Germany, 2005
• WP6 Evaluation using PCOM and eLearning
  applications
• E.g. SPP Demonstrator

100
75
50
0
100
50
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Priority Programme Integration
Components

• Demonstrator Multihop Presenter
• Pervasive Presenter(Component-based Application)
• PCOM (Component System)
• BASE (Object-oriented Middleware)

PCOM Container
Semantic Service Matching

• Semantic Service Matching (Jena)
• Service Mgmt and Discovery (Aachen)
• Mobility-aware Multicast (Karlsruhe)

Contract Framework
Configuration Algorithms
Resource Management
Efficient Service Discovery
BASE Micro-broker
Invocation Broker
Registries

• Position-based Multicast (Mannheim)
• Publish/Subscribe Middleware (Magdeburg)
• Routing Emulation(Marburg)

Plugin Manager
Communication (Routing, Multicast)
Discovery Communication Plugins
...
Emulation
Network
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Summary

• Ubiquitous Computing requires self-configuring
  applications
• Basis Basic abstractions for adaptive
  applications (PCOM)
• Goal Provide suitable algorithms for automatic
  (re-)configuration
• Approach Map configuration to CSP and extend
  existing algorithms
• Status On schedule
• Priority Programme Integration
• Synergetic and complementary research
• Emulation, Service Discovery, Multi-hop Routing,
  Multicast, Semantic Service Matching,
• Common demonstrator
• Marburg, Mannheim, Magdeburg

14
More Resources

• Web
• www.3pc.info
• Some references
• C. Becker, G. Schiele, H. Gubbels, K. Rothermel
  BASE - A Micro-broker-based Middleware For
  Pervasive Computing, IEEE International
  Conference on Pervasive Computing and
  Communication (PerCom), Fort Worth, USA , 2003
• C. Becker, M. Handte, G. Schiele, K. Rothermel
  PCOM A Component System for Pervasive
  Computing, IEEE International Conference on
  Pervasive Computing and Communication (PerCom),
  Orlando, USA , 2004
• M. Handte, C. Becker, K. Rothermel Peer-based
  Automatic Configuration of Pervasive
  Applications, IEEE International Conference on
  Pervasive Services (ICPS) 2005, Santorini,
  Greece, 2005
• E-Mail
• kurt.rothermel christian.becker
  marcus.handte _at_ informatik.uni-stuttgart.de