Page 290 - Software and Systems Requirements Engineering in Practice

ç ç 3 O F T W A R E ç ç 3 Y S T E M S ç 2 E Q U I R E M E N T S ç % N G I N E E R I N G ç ) N ç 0 R A C T I C E

4HE CONSISTENCY BETWEEN MULTIPLE ARTIFACTS IS THE RESPONSIBILITY OF THE
INVOLVED STAKEHOLDERS WHO MUST BE ACTIVELY INVOLVED WITH ALL ARTIFACTS
THAT RELATE TO THEIR AREA OF INTEREST AND EXPERTISE
4HE DESIRE TO OPTIMIZE THE PROTOTYPING PROCESS AROUND THE
FASTEST POSSIBLE FEEDBACK LOOP HAS A SIGNIFICANT IMPACT ON THE NATURE
OF THE CHOSEN PROTOTYPE ! MOCK UP PROTOTYPE IS USUALLY EASIER THAN
AN EXECUTABLE PROTOTYPE TO MANIPULATE BY MULTIPLE STAKEHOLDERS
AND THIS MAKES SUCH MOCK UPS THE LOGICAL FIRST STEP IN DEVELOPING
CONSENSUS !N EXECUTABLE MODEL IS LIKEWISE USUALLY FASTER TO MODIFY
AND EVOLVE WITHIN ITS BOUNDARIES THAN AN EXECUTABLE PROTOTYPE AND
SHOULD TAKE PRECEDENCE FOR THE SUPPORTED ASPECTS OF SYSTEM
FUNCTIONALITY 4HE CHOICE OF TECHNOLOGY AND PROTOTYPING PROCESS IS
ALSO SUBJECT TO THE GOAL OF OPTIMIZING THE FEEDBACK PARTICULARLY BY
MINIMIZING THE PROTOTYPE DEVELOPMENT TIME AND EFFORT ! TARGET
PRODUCT TECHNOLOGY MAY BE SKIPPED IN FAVOR OF ANOTHER TECHNOLOGY
THAT MODELS THE BEHAVIOR IN A SATISFACTORY WAY WHILE PROVIDING A
FASTER OR MORE POWERFUL PROTOTYPE DEVELOPMENT AND CODE GENERATION
ENVIRONMENT FOR A THROWAWAY PROTOTYPE !LSO EVOLUTIONARY
PROTOTYPING REQUIRES THE DEVELOPERS TO CONCENTRATE VERY EARLY ON
ARCHITECTURE AND QUALITY ISSUES 4HROWAWAY PROTOTYPES ARE LIKELY TO
PROVIDE FASTER PROGRESS ON REQUIREMENTS UNDERSTANDING SINCE THEY
ARE EASIER TO MODIFY 7HEN CREATING THROWAWAY PROTOTYPES CARE
MUST BE TAKEN TO MANAGE STAKEHOLDER EXPECTATIONS E G THE
CUSTOMER SHOULD CLEARLY UNDERSTAND THAT THE DELIVERABLE IS NOT A
VIABLE PRODUCT
7HILE THE SPEED OF COLLECTING FEATURE SOLUTION FEEDBACK IS THE
PARAMOUNT GOAL IN REQUIREMENTS PROTOTYPING MANY OTHER ASPECTS OF
PRODUCT DEVELOPMENT STILL PLAY AN IMPORTANT ROLE IN THIS PROCESS )N
ORDER TO PROVIDE RELIABLE FEEDBACK THE PROTOTYPE NEEDS TO BE
REPRESENTATIVE OF THE DESIRED FEATURE AND UNAMBIGUOUSLY UNDERSTOOD
BY THE STAKEHOLDERS 4HIS IMPLIES THAT A CERTAIN MINIMUM LEVEL OF
QUALITY OF PRESENTATION MUST BE ACHIEVED AND MAINTAINED !LSO THE
COMPLEXITY OF THE PROTOTYPE MAY GROW BEYOND LEVELS WHERE AD HOC
HACKING CAN MAINTAIN THE PROTOTYPE AT THE NEEDED QUALITY LEVEL
%XPECTED AND ATTAINED COMPLEXITY SHOULD BE USED AS A GUIDE IN
DEFINING THE ARCHITECTURE AND PROTOTYPING PRACTICES

õ 4IPSõFORõ0ROTOTYPING
4O SUMMARIZE SOME OF THE PROTOTYPING PRACTICES DESCRIBED AND MAKE
THEM MORE PRESCRIPTIVE FOR THE PRACTITIONER WE SUGGEST THE FOLLOWING
RULES FOR PROTOTYPING 4HESE TIPS FOR PROTOTYPING ARE ADAPTED FROM
THE RULES FOR SOFTWARE DEVELOPMENT USING AGILE PRINCIPLES FOUND IN
;0OPPENDIECK ET AL =
v %LIMINATE UNNECESSARY WORK -ANY QUALITY PROCESSES STRIVE
TO FIND DEFECTS EARLY IN THE DEVELOPMENT PROCESS &OR RAPID
PROTOTYPING EXTENSIVE TESTING OF A PROTOTYPE AND WRITING