Integration between Organizational Requirements and Architecture

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Integration between Organizational Requirements
and Architecture

• Lucia Bastos Jaelson Castro

Banco do Brasil S.A. UF Tecnologia Brasília
DF Centro de Informática Universidade Federal
de Pernambuco - Ufpe Recife 50732-970, Brazil
Novembro, 2003
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Contents

• Motivation
• Tropos Project
• The SIRA framework Proposal
• Final Considerations and Future Works

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Motivation
Index

• Semantic Gap between Requirements and
  Architecture
• Requirements are derived from concepts and
  relationships in the problem domain (for example,
  e-commerce, bank accounting) and architecture
  models a solution for the problem described in
  the requirements
• This conceptual differences between what to do
  (requirements) versus how to do (architecture)
  is one of the challenging problem in software
  engineering
• Goal-based Organizational Models
• Goals can be related to functional abilities,
  business and system qualities
• Goals can be used as starting point to construct
  the architectural description
• Related Works

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Related Works
Index

• Twin Peaks Model
• Emphasizes the equality for requirements and
  architecture
• CBSP Approach
• Intermediate language for refining requirements
  into architecture by applying a taxonomy of
  architectural dimensions
• KAOS Approach
• Goal-oriented process that partially intertwines
  requirements and architecture elaboration.

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Tropos Project
Index
Ontology
Actors, social dependencies, goals, resources,...
Application area
(Requirements-driven) Software development
Tropos context
Tropos, in Greek, means manner (as in manner
of doing things)
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Tropos Context
Index
I Organizational modeling framework - Early and
Late requirements Architectural Design Socio
Intentional Catalogue
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i - E-Commerce System Case Study
Four kinds of dependency
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Operational Context of the System
Organizational Map

• Functions and qualities for the system within
  its environment

Index
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Architectural Catalogue and Quality Attributes
Predictability, Security, Adaptability,
Cooperativity, Competitivity, Availability,
Integrity, Modularity, Aggregability
() contributes positively (very positively)
- (--) contributes negatively (very negatively)
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Proposal for Systematic Integration between
Requirements and Architecture
Index
Tropos
The SIRA Framework
SIRA Elements
Schemas
Templates
Guidelines
SIRA Process
i Requirements model
i SystemGroup schema
Architectural catalogue
i architectural model
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The SIRA Elements Concepts and Representations

• To augment the i requirements information with
• Schemas
• Each schema represents, in i notation, the
  relationships between requirements elements
  (System actors) and SIRA elements (System Group,
  Sub group and System Roles) The output set is
  named System Group Schema.
• Templates
• Each template are used to capture and to refine
  the complementary properties from SIRA elements
  represented in each schema
• Guidelines
• Used to relate elements (i -gt SIRA -gt
  architecture)

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SIRA Elements

• System Group - The software actors of the
  architecture. A System Group can be a component
  or sub-components of a software system, like
  Medi_at_ actor to sell media items in Internet
• Each System Group can be refined into Sub Group
  to provide some service in a particular context
• System Roles Each Sub Group assume some
  behavior to execute a service in the context
• Responsibility Services and capabilities
  assigned to a System Group or Sub-Group.
  Responsibility is extracted from the set of tasks
  to be performed and goals to be fulfilled by
  system actors, like Place order or Buy media
  items.
• Constraint Assertions and constraints that
  apply to the entire component (System Group),
  like security or availability
• Architectural Elements Represents the elements
  in architectural model. They are components and
  its interactions.

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SIRA System Group

• The Role Theory applied for enterprise modeling
• Individuals occupy positions in an organizations
• Associated to each position is a set of
  activities that constitute the responsibilities
  of that positions
• A organizational structure can define the roles
  of various components (actors), their
  responsibilities defined in terms of goals and
  tasks they have assigned and resources allocated
• Organizations consist of a collection of group
  (or a set of actors). A group represents a
  context of a role.
• The SIRA Framework uses the Role Theory concepts
• Software (i System actor) occupies a position
  that correspond a group (or a collection of
  sub-groups)
• (e-commerce example i SR and SIRA Schema)

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System Group Schemas E-commerce example
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Templates

• Partial template definition of a main component
  with complementary architectural definitions.
• The Name attribute is the i specification from
  which the element (actor) was derived. In our
  example Medi_at_ actor is a system component.
• The System Roles attribute is an initial list of
  responsibility assignment (tasks and goals).
• Composed of attribute identifies the
  sub-components that implement the component

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The SIRA Process
Index
Relating SIRA Elements and Architectural
Elements
Analyzing Requirements Elements
Selecting Architecture
i Requirements models, Architectural catalogue,
and SIRA Elements definition
System Group Schema and i Architectural model
Architectural model
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1 - Analyzing Elements

• This activity consist of analyzing the i
  elements (System actor) to identify an possible
  SIRA Element
• Each system actor candidate will be analyzed to
  create a new System Group Schema.
• Three sub-activities
• Identify the Correlation between i Strategic
  Dependency Model and SIRA Elements
• Identify System (System actor) Responsibilities
• Identify System Roles

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2 Selecting Architecture

• This activity consist of selecting among
  alternative architectural styles
• Two sub-activities
• Identify the Architectural Constraints
• Each architecture must conform to the application
  domain qualities. (e-commerce example)
• Apply NFR Framework
• Each architectural candidate will be analyzed
  based on positive contributions to priority
  qualities (constraints) of the application domain

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2.1 - NFR Framework
From Security, Availability, Adaptability
() contributes positively (very positively)
- (--) contributes negatively (very negatively)
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3 Relating SIRA Elements and Architectural
Elements

• This activity consist of deriving the
  relationship between SIRA elements and
  architectural elements. This relationship can be
  identified by Sub-Group Functionality and Roles.
• Three sub-activities
• Identify Architectural Components (selected Joint
  Venture Style and medi_at_ components)
• Identify Task/Goals/Resource Dependency between
  Sub-Groups
• Identify Architectural Connectors and Protocols
• E-commerce architecture

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Joint Venture Style

• Based on a agreement between two or more
  principal partners.
• Principal Partner Autonomous on a local
  dimension and interacts directly with other
  principal partners to exchange services, data and
  knowledge
• Joint Management actor coordinates tasks and
  manages the sharing of knowledge and resources.
• Secondary Partners Supply services or support
  tasks for the organization core
• Joint Venture in i notation

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Joint Venture in i
Index
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3.1 Architectural ComponentsMedi_at_ Actor and
Joint Venture components
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A Joint-Venture E-commerce Architecture
Index
From Security, Availability, Adaptability
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Final Considerations Research contributions
Index

• Narrowing the gap between requirements gtlt
  architectures
• Requirement specification supported by a
  development methodology, the Tropos Methodology
• Using same concepts for requirements and
  architectures
• Description in i framework
• Software architecture as social organization
• Mapping requirements into architecture and
  maintaining consistency and traceability
• Refining requirement and architecture
  specifications into a systematic process

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Future Works
Index

• Investigation of recent works in the Tropos
  community point to detect other solutions
  researched
• Investigation of recent works in component-based
  approach
• Study and improvement of the schemas, templates
  and guidelines
• Real study case to evaluate the obtained results