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Fichier Détails
| Cartes-fiches | 15 |
|---|---|
| Langue | English |
| Catégorie | Informatique |
| Niveau | Université |
| Crée / Actualisé | 27.11.2012 / 03.05.2015 |
| Lien de web |
https://card2brain.ch/box/system_modelling_l2
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What is a requirement?
A requirement is (IEEE Std 610.12.-1990)
1. A condition or capability of a system needed by a user to solve a problem or achieve an objective;
2. A condition or capability that must be met or possessed by a system or system component to satisfy a contract, standard, specification, or other formally imposed document;
3. A documented representation of a condition or capability as in (1) or (2).
Requirements discovery
Requirements discovery identifies the scope and the major objectives of the
system.
> Requirements discovery is a finite phase in the development process.
Requirements gathering
Requirements gathering defines what is needed to reach those objectives.
> Requirement gathering is an ongoing activity throughout most of the
project.
Classifying requirements
Requirements fall into two broad categories
> Functional requirements: Functional requirements specify the behavior of the
system and the constraints on that behavior.
> Non-functional requirements: Non-functional requirements specify non-behavioral properties of the system and the constraints on those properties.
– Since both relate to the same system, they are interrelated and affect each other.
What do functional requirements specify
– The most top-level functional requirement expresses the mission of the system.
– Typically, a system provides a set of capabilities in order to accomplish the mission.
What do non-functional requirements specify
Usability
> Usability requirements specify how the behavior of the system must be
shaped in order to fit the users’ abilities and their work environment.
» Design of the user interface
Reliability
> Reliability requirements specify the dependability of the system both in time
and in the fulfillment of its functions.
Performance
> Performance requirements specify the response time and the input-output volume that that the system can handle within a particular timeframe
Maintainability
> Maintainability requirements specify the ability of the software to be modified and enhanced
Security
> Security requirements specify the right of access to the services of a system, the manner of access to those services, and the tracing of interactions with the system
Requirements analysis techniques
- Interviews: focused or structured
- Questionnaires
- Workshops
- Field Trips and Observation
- Modeling
- Mock-Ups
Interview building blocks
- Interviewee profile
- Current environment
- General expectations
- constraints
- open-ended questions
- closed questions
- probes
- verification and recap
sources of requirement analysis
- sponsor
- domain experts
- stakeholders
- users
- reverse engineering
7 steps of requirement management
1. document and update requirements
2. document sources
3. decompose requirements
4. uniquely identify requirements
5. very requirements and document verifications
6. prioritize requirements
7. classify requirements
domain analysis = understanding the problem (5)
- requirements discovery
- domain definition
- domain analysis
- domain dictionary
- conceptual modeling
def business domain
A business domain is an area of related activities that operate on a set of shared rules
and concepts.
def domain analysis
Domain analysis is discovering and defining concepts that the information system must incorporate or take into account in order to meet its objectives.
relevant domain concepts
- role
- objects
- processes
- rules
conceptual modeling
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