mathematics

Non-functional requirements framework

Non-functional requirements framework is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Non-functional requirements framework rather than just read about it. In short: NFR (Non-Functional Requirements) need a framework for compaction. The analysis begins with softgoals that represent NFR which stakeholders agree upon.

Key takeaways

Non-functional requirements framework belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Non-functional requirements framework to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Non-functional requirements framework from memory before moving on to harder problems.

Reference excerpt

NFR (Non-Functional Requirements) need a framework for compaction. The analysis begins with softgoals that represent NFR which stakeholders agree upon. Softgoals are goals that are hard to express, but tend to be global qualities of a software system. These could be usability, performance, security and flexibility in a given system. If the team starts collecting them it often finds a great many of them. In order to reduce the number to a manageable quantity, structuring is a valuable approach. There are several frameworks available that are useful as structure.

Structuring Non-functional requirements The following frameworks are useful to serve as structure for NFRs:

Goal Modelling The finalised softgoals are then usually decomposed and refined to uncover a tree structure of goals and subgoals for e.g. the flexibility softgoal. Once uncovering tree structures, one is bound to find interfering softgoals in different trees, e.g. security goals generally interferes with usability. These softgoal trees now form a softgoal graph structure. The final step in this analysis is to pick some particular leaf softgoals, so that all the root softgoals are satisfied. IVENA - Integrated Approach to Acquisition of NFR The method has integrated a requirement tree. Context of an Organization There are several models to describe the context of an organization such as Business Model Canvas, OrgManle, or others. Those models are also a good framework to assign NFRs.

Measuring the Non-functional requirements SNAP is the Software Non-functional Assessment Process. While Function Points measure the functional requirements by sizing the data flow through a software application, IFPUG's SNAP measures the non-functional requirements. The SNAP model consists of four categories and fourteen sub-categories to measure the non-functional requirements. Non-functional requirement are mapped to the relevant sub-categories. Each sub-category is sized, and the size of a requirement is the sum of the sizes of its sub-categories. The SNAP sizing process is very similar to the Function Point sizing process. Within the application boundary, non-functional requirements are associated with relevant categories and their sub-categories. Using a standardized set of basic criteria, each of the sub-categories is then sized according to its type and complexity; the size of such a requirement is the sum of the sizes of its sub-categories. These sizes are then totaled to give the measure of non-functional size of the software application. Beta testing of the model shows that SNAP size has a strong correlation with the work effort required to develop the non-functional portion of the software application.

Worked examples

Example 1 — a first encounter with Non-functional requirements framework

Start with the simplest possible case. Write down what Non-functional requirements framework claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Non-functional requirements framework before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Non-functional requirements framework ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Non-functional requirements framework

In research: Non-functional requirements framework appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Non-functional requirements framework in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Non-functional requirements framework is common in secondary-school and first-year university syllabi. It links to neighbouring topics Software requirements, Systems engineering, so understanding it makes those chapters shorter.
In everyday life: Look for Non-functional requirements framework outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Non-functional requirements framework in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Non-functional requirements framework means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Non-functional requirements framework out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Non-functional requirements framework in simple terms?

NFR (Non-Functional Requirements) need a framework for compaction. The analysis begins with softgoals that represent NFR which stakeholders agree upon.

Why does Non-functional requirements framework matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Non-functional requirements framework?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Non-functional requirements framework.