95:
description of the required behavior, which must be clear and readable. The described behavior may come from organizational or business rules, or it may be discovered through elicitation sessions with users, stakeholders, and other experts within the organization. Many requirements may be uncovered during the use case development. When this happens, the requirements analyst may create a placeholder requirement with a name and summary, and research the details later, to be filled in when they are better known.
58:(also known as "quality requirements"), which impose constraints on the design or implementation (such as performance requirements, security, or reliability). Generally, functional requirements are expressed in the form "system must do <requirement>," while non-functional requirements take the form "system shall be <requirement>." The plan for implementing functional requirements is detailed in the system design, whereas
86:
requirement is implemented/incorporated. Each use case illustrates behavioral scenarios through one or more functional requirements. Often, though, an analyst will begin by eliciting a set of use cases, from which the analyst can derive the functional requirements that must be implemented to allow a user to perform each use case.
85:
request β analyze β use case β incorporate. Stakeholders make a request; systems engineers attempt to discuss, observe, and understand the aspects of the requirement; use cases, entity relationship diagrams, and other models are built to validate the requirement; and, if documented and approved, the
49:
Functional requirements may involve calculations, technical details, data manipulation and processing, and other specific functionality that define what a system is supposed to accomplish. Behavioral requirements describe all the cases where the system uses the functional requirements, these are
94:
A typical functional requirement will contain a unique name and number, a brief summary, and a rationale. This information is used to help the reader understand why the requirement is needed, and to track the requirement through the development of the system. The crux of the requirement is the
80:
In some cases a requirements analyst generates use cases after gathering and validating a set of functional requirements. The hierarchy of functional requirements collection and change, broadly speaking, is:
73:, functional requirements specify particular results of a system. This should be contrasted with non-functional requirements, which specify overall characteristics such as cost and
77:. Functional requirements drive the application architecture of a system, while non-functional requirements drive the technical architecture of a system.
199:
212:
46:
or its component, where a function is described as a summary (or specification or statement) of behavior between inputs and outputs.
373:
336:
309:
284:
256:
175:
325:
MITRE Corporate
Communications and Public Affairs. "Requirements Engineering: Eliciting, Collecting, and Developing Requirements".
402:
326:
407:
104:
55:
244:
124:
70:
74:
139:
114:
109:
218:
31:
82:
63:
35:
369:
332:
305:
280:
252:
208:
171:
129:
363:
165:
134:
144:
300:
JΓΆnsson P, Lindvall M (2006). "Chapter 6: Impact
Analysis". In Aurum A, Wohlin C (eds.).
119:
17:
275:
Adams, K.M. (2015). "3.2 Definitions for
Functional and Non-Functional Requirements".
396:
167:
Airborne
Electronic Hardware Design Assurance: A Practitioner's Guide to RTCA/DO-254
164:
Fulton R, Vandermolen R (2017). "Chapter 4: Requirements - Writing
Requirements".
362:
Stellman, Andrew; Greene, Jennifer (2005). "Chapter 6: Software requirements".
243:
Loucopoulos, P. (2005). "Chapter 4: Requirements
Engineering". In Clarkson J,
51:
43:
304:. Springer Science & Business Media. pp. 117β42.
277:
198:"Supplement 4-A, A Procedure for Requirements Analysis".
249:
Design
Process Improvement: A Review of Current Practice
357:
355:
27:Any task which a system must be able to complete
302:Engineering and Managing Software Requirements
8:
270:
268:
54:. Functional requirements are supported by
207:. United States Government US Army. 2001.
156:
331:. MITRE Corporation. pp. 304β13.
251:. Springer-Verlag. pp. 116β139.
7:
368:. O'Reilly Media. pp. 97β130.
365:Applied Software Project Management
328:The MITRE Systems Engineering Guide
25:
62:requirements are detailed in the
201:Systems Engineering Fundamentals
1:
170:. CRC Press. pp. 89β93.
279:. Springer. pp. 45β50.
105:Function (computer science)
56:non-functional requirements
424:
125:Functional decomposition
71:requirements engineering
42:defines a function of a
18:Functional requirements
140:Separation of concerns
115:Function (mathematics)
110:Function (engineering)
40:functional requirement
403:Software requirements
32:software engineering
408:Systems engineering
64:system architecture
36:systems engineering
224:on 31 January 2017
130:Functional design
16:(Redirected from
415:
387:
386:
384:
382:
359:
350:
349:
347:
345:
322:
316:
315:
297:
291:
290:
272:
263:
262:
240:
234:
233:
231:
229:
223:
217:. Archived from
206:
195:
189:
188:
186:
184:
161:
135:Functional model
21:
423:
422:
418:
417:
416:
414:
413:
412:
393:
392:
391:
390:
380:
378:
376:
361:
360:
353:
343:
341:
339:
324:
323:
319:
312:
299:
298:
294:
287:
274:
273:
266:
259:
242:
241:
237:
227:
225:
221:
215:
204:
197:
196:
192:
182:
180:
178:
163:
162:
158:
153:
145:Software sizing
101:
92:
28:
23:
22:
15:
12:
11:
5:
421:
419:
411:
410:
405:
395:
394:
389:
388:
374:
351:
337:
317:
310:
292:
285:
264:
257:
235:
214:978-1484120835
213:
190:
176:
155:
154:
152:
149:
148:
147:
142:
137:
132:
127:
122:
120:Function point
117:
112:
107:
100:
97:
91:
88:
69:As defined in
60:non-functional
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
420:
409:
406:
404:
401:
400:
398:
377:
375:9780596553821
371:
367:
366:
358:
356:
352:
340:
338:9780615974422
334:
330:
329:
321:
318:
313:
311:9783540282440
307:
303:
296:
293:
288:
286:9783319183442
282:
278:
271:
269:
265:
260:
258:9781846280610
254:
250:
246:
239:
236:
220:
216:
210:
203:
202:
194:
191:
179:
177:9781351831420
173:
169:
168:
160:
157:
150:
146:
143:
141:
138:
136:
133:
131:
128:
126:
123:
121:
118:
116:
113:
111:
108:
106:
103:
102:
98:
96:
89:
87:
84:
78:
76:
72:
67:
65:
61:
57:
53:
47:
45:
41:
37:
33:
19:
379:. Retrieved
364:
342:. Retrieved
327:
320:
301:
295:
276:
248:
238:
226:. Retrieved
219:the original
200:
193:
181:. Retrieved
166:
159:
93:
79:
68:
59:
50:captured in
48:
39:
29:
83:stakeholder
75:reliability
397:Categories
151:References
52:use cases
247:(eds.).
245:Eckert C
228:18 March
99:See also
381:15 June
344:15 June
183:15 June
90:Process
372:
335:
308:
283:
255:
211:
174:
44:system
222:(PDF)
205:(PDF)
81:user/
383:2018
370:ISBN
346:2018
333:ISBN
306:ISBN
281:ISBN
253:ISBN
230:2016
209:ISBN
185:2018
172:ISBN
38:, a
34:and
30:In
399::
354:^
267:^
66:.
385:.
348:.
314:.
289:.
261:.
232:.
187:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.