Discovering Web Services To Specify More Complete Requirements

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Discovering Web Services To Specify More Complete
Requirements

• Rhydian Howell-Morris, Konstantinos Zachos,
  Xiaohong Zhu, Neil Maiden and Sara Jones

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SeCSE - secse.eng.it

• EU-funded SeCSE IP
• 10m 4-year project on service-centred systems
• Mission statement
• Create new methods, tools and techniques for
  systems integrators and service providers that
  support the cost-effective development and use of
  dependable services and service-centric
  applications
• Four activity areas
• Service engineering specification of services
• Service discovery discovering and retrieving
  services at development, deployment and run-time
• Systems engineering service-oriented
  architectures
• Service delivery deploying, monitoring and
  switching services
• Industrial evaluation and application
• Fiat, DaimlerChrysler, Telecom Italia,
  Telefonica, Computer Associates, Microsoft, ATOS,
  Engineering

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Problem Challenge

• Integration
• service discovery selection processes into
  established systems development methods ? extra
  tasks!
• Trade-off
• too many tasks can critically reduce the
  usability and adoption of a method
• manual generation of new artifacts such as
  service requests from requirements can lead to
  incomplete and inconsistent queries
• ? Seamless integration of a service discovery
  method within existing development processes

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SeCSE Requirements Process

• Flexible processes
• Different configurations of processes, techniques
  and tools

Query(s)
Queries
Service integrators consumers
Requirements
Service registry
Discovered services
Changed requirements
Service integrators consumers
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SeCSEs Registry

• Faceted specification
• A service specification is not a single entity
  but is a composition of a number of
  sub-specifications ? facet
• 7 facets signature, service description,
  operational semantics, exception,
  quality-of-service, cost/commerce, testing
• Different notations may be used in different
  facets to describe that sub-specification
• Requirements-based service discovery currently
  uses service description and quality-of-service
  facets

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UCaREs Conceptual Architecture

• Use Case Reqs specification
• Service Request/Query generation

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SeCSEs Discovery Engine (EDDiE)
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Automotive Domain Example

• Customizable telematics devices in FIAT vehicles
• Services for repair diagnostics, navigation,
  spares, etc
• Initial use case precis
• A driver is driving his car. The cars on-board
  diagnostic system detects an engine problem. The
  engine is misfiring. The driver activates FIATs
  remote-maintenance service. The service provides
  the location of the nearest garage to repair the
  car. The driver follows directions to the garage
• Initial requirements
• FR1 The remote-maintenance service shall
  diagnose all faults with the cars engine.
• PR1 The remote-maintenance service shall
  diagnose all faults within 5 minutes of their
  detection.

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Use case-based specification of requirements
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Ontology-based quantification of requirements
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Manipulation of use case specifications
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Seamless formulation of service requests
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Retrieved services
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Filter services using non-functional requirements
compliance
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Future Work

• UCaRE/REDEPEND integration
• receive queries from business models expressed in
  i notation
• Query decomposition and granularity
• sub queries to match with lower granularity
  services in registry
• increase likelihood of discovering available
  services
• Agent-driven Service Discovery
• intelligent search agents automatically form and
  revise service queries in background mode whilst
  the analyst specifies requirements
• retrieve and present descriptions of services
  that agents infer are useful during requirements
  tasks.
• Industrial Evaluation
• Computer Associates, KD
• Exploring validation and integration with IBM
  Rational

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• Thank you for your attention!
• Questions?

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Disambiguation Strategies

• Determine correct WordNet sense of each term
• Essential for effective expansion of query terms
• Seven procedures - increasing cost to apply
• Selecting senses from glossary
• Selecting sense of term with only 1 possible
  sense
• Selecting senses of synonyms of terms that have
  already been disambiguated
• Selecting senses of hononyms of terms that have
  already been disambiguated
• Selecting senses that are most frequently used
• Context-based selection of senses - based on
  senses of terms before and after
• User selects the correct sense during service
  discovery

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Expansion Strategies

• Expand service queries with more terms
• Increases likelihood of discovering services not
  expressed using identical terms
• Cannot rely on problem domain ontologies
• Nature of requirements, use WordNet as ontology
• Three term expansion procedures
• Synset expansion, with terms with similar meaning
• Hypernym expansion, with terms with more generic
  meaning
• Gloss expansion, with selected terms from
  definition of the original term

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Do these Modules Help?

• Evaluated UCaRE and Service Browser
• Ran half-day automotive requirements workshop
  with 4 analysts - 2 from Centre Research FIAT, 1
  from DaimlerChrysler, 1 from Computer Associates
• Workshop in 3 phases
• Walked through use case to discover requirements
• Retrieved services from registry of 112 service
  descriptions
• Walked through retrieved services to discover
  requirements not found using earlier walkthrough

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Outcomes from Requirements Workshop

• Workshop basics
• Phase 1 lasted 60 minutes 27 requirements
  specified
• Phase 2 lasted 10 minutes 11 services retrieved
• Phase 3 lasted 50 minutes 8 services retained as
  relevant 20 requirements specified
• Retrospective questionnaire results