A Requirement-Driven Development Methodology

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A Requirement-Driven Development Methodology

• Jaelson Castro Manuel Kolp John
  Mylopoulos

Department of Computer Science University of
Toronto Toronto M5S 3G4, Canada
Centro de Informática Universidade Federal
de Pernambuco Recife 50732-970, Brazil
CAiSE01 - June 6 2001, Interlaken, Switzerland
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Requirements-Driven Development

• Information Systems should be designed to match
  their Social Operational Environment.
• Operational environment stakeholders,
  qualities, responsibilities, objectives, and
  resources, roles, needs...
• Versus information systems a collection of
  (software) modules, data structures and
  interfaces.
• Impedance Mismatch ? Poor quality, Failure
• Why not requirements-driven to avoid that
  mismatch?
• Social and Intentional concepts not only for
  Early Requirements but the Entire Development
  Life Cycle
• ? ? TROPOS (http//www.cs.toronto.edu/km/tropos)

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Where Do We Want to Go?
Agent-oriented programming
i
TROPOS
GAIA
KAOS
Z
AUML
UML, Catalysis Co.
!! The GAP !!
Detailed design
Early requirements
Architectural design
Late requirements
Implementation
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1. Early Requirements Analysis with TROPOS

• Understanding the problem by studying an
  organizational setting
• Organizational model with relevant actors and
  respective goals.
• i Yu95
• Running Example A Business to Consumer System

Goals are relative, fulfillment is collaborative
!!
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Rationale Analysis
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2. Late Requirements (Strategic Relationships)
Organizational Map

• Functions and qualities for the system within
  its environment

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A Formal Framework ? Precise Semantics

• Entity Order
• Has orderId Number, cust Customer, date
  Date,
• tems SetOf MediaItem
• Entity MediaItem
• Has itemId Number, itemTitle String,
  description Text, editor String
• Actor Customer
• Has customerId Number, name Name, address
  Address, tel PhoneNumber,
• Capable of MakeOrder, Pay, Browse,
• Goal "orderOrder buyBuyMediaItemsorder
  (order.custself Ù?Fulfil(buy))
• Actor MediaShop
• Has name MediaLive, address 735 Yonge
  Street, phone [phone]
• Capable of Sell, Ship, SendInvoice,
• Goal msIncreaseMarketShare(Fulfil(ms))

• GoalDependency BuyMediaItems
• Mode Fulfil
• Has order Order
• Defined ItemsReceivedOK(order)
• Depender Customer
• Dependee MediaShop
• Necessary Fulfil( PlaceOrder(order))
• SoftGoalDependency IncreaseMarketShare
• Mode Maintain
• Depender MediaShop
• Dependee Customer
• Necessary "custCustomer placePlaceOrderorder
  (order.custcust ) Ù ?Fulfil(place))
• Action MakeOrder
• Performed By Customer
• Refines PlaceOrder
• Input cust Customer, date Date, items
  SetOf MediaItem
• Output order Order
• Post order.cust cust Ù order.date date Ù
  order.items ? items

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Late Requirements - System Rationale Model
Rationale Map
Medi_at_
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Goal Analysis


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-

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Collect orders

Select Item
By person
By system
Manually
Automatically
By phone
By Fax
With Shopping Cart
Have updated invoices
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Leaving Goals Dependencies is a Novelty

• Goals and Softgoals generally operationalized/metr
  icized during Late Requirements (e.g. KAOS van
  Lamsweerde 93)
• Ex. Security operationalized by interfaces
  which minimize input/output or access restriction
  to sensitive information.
• Steps through which goals are to be fulfilled are
  frozen in the requirements
• Systems fragile and less reusable.
• Whenever there is a need for flexibility,
  reusability, modularity

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3. Architectural Design

• Architecture in terms of interconnected social
  components.
• 3 levels
• 1 Macro level Organizational Styles
  (Organization Theory)
• Vertical Integration, Pyramid, Joint Venture,
  Structure in 5, Bidding, Hierarchical
  Contracting, Co-optation, Takeover
• 2 Micro level Patterns (Agent, COOPIS
  Community)
• Broker, Matchmaker, Contract-Net, Mediator,
  Monitor, Embassy, Wrapper, Master-Slave, ...
• 3 Atomic Social and intentional concepts i

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Organizational Styles and Social Patterns
Joint Venture
Matchmaker
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Software Quality Attributes

• Predictability, Security, Adaptability,
  Cooperativity, Competitivity, Availability,
  Failability, Modularity, Aggregability,

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Selecting System Architecture
Chung00
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A Joint-Venture E-commerce Architecture
E-Business Organizational Map
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Assigning Agent Roles to Actors
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4. Detailed Design

• Architectural Agent components defined in details
  in terms of inputs, outputs, control, and other
  relevant information.

Check Out Plan
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Agent Interaction Protocol with AUML

• The Checkout Dialogue

Customer
Shopping Cart
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From i to Agent Concepts
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Partial JACK Implementation for checking out
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Conclusion

• Software Engineering in 2025 Requirements
  Engineering Software Geriatry ? van
  Lamsweerde ICSE00 Keynote
• Narrowing the gap between requirements and
  architectures
• ...we dont want to freeze any more solutions to
  a given requirement in the software designs we
  produce!!
• IS (ERP, KM, e-business, e-marketplace,
  groupware, CRM, ... ) in terms of the same social
  and intentional modeling concepts
• i from early requirements to detailed design.
• formal Tropos language (inspired by KAOS)
• formal analysis techniques temporal (model
  checking), goal, and social structures, ...