Typically natural language requirements and requirements models are frequently

Typically natural language requirements and

This preview shows page 106 - 110 out of 182 pages.

ments can be documented by means of models. Typically, natural language requirements and requirements models are frequently employed in con- junction so that the advantages of both forms of documentation can be exploited. Model-based documentation of requirements has, among other things, the advantage that graphical (imagelike) descriptions of circum- stances can be understood faster and better than natural-language descriptions. Among the models that are frequently used in requirements engineering are goal models (e.g., in the form of AND/OR trees) and use case diagrams as well as conceptual models to document requirements from three perspectives: data, functional, and behavioral. For each of these three perspectives, there are suitable conceptual modeling languages that provide purpose-specific means to document the information depicted in each respective perspective.
Image of page 106

Subscribe to view the full document.

Image of page 107
89 7 Requirements Validation and Negotiation Validation and negotiation during requirements engineering is meant to ensure that the documented requirements meet the predetermined quality criteria, such as correctness and agreement (see section 4.6 ). The intro- duced principles and techniques can be used to validate and negotiate indi- vidual requirements or entire requirements documents. 7.1 Fundamentals of Requirements Validation During the requirements engineering activity, it is necessary to review the quality of the requirements developed. Among others, the requirements are presented to the stakeholders with the goal to identify deviations between the requirements defined and the stakeholders’ actual wishes and needs. Approving requirements During requirements validation, the decision of whether a require- ment possesses the necessary level of quality is made (see chapter 4 ) and whether the requirement can be approved to be used for further develop- ment activities (such as design, implementation, and testing). This deci- sion should be made on the basis of predefined acceptance criteria. Goal of validation The goal of requirements validation is therefore to discover errors in the documented requirements. Typical examples of errors in requirements are ambiguity, incompleteness, and contradictions (see section 7.3 ). Error proliferation Requirements documents are reference documents for all further development activities. Therefore, errors negatively affect all further development activities. A requirements error that is discovered when the system is already deployed and operating requires all artifacts affected by the error to be revised, such as source code, test artifacts, and architectural descriptions. Correcting errors in requirements once the system is in operation therefore entails significant costs.
Image of page 108

Subscribe to view the full document.

90 7 Requirements Validation and Negotiation Legal risks A contract between client and contractor is often based on require- ments documents. Critical errors in requirements can lead to the fact that contractual agreements cannot be met, e.g., scope of supply and services, expected quality, or completion deadlines.
Image of page 109
Image of page 110

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes