Objective: The objective of this chunk is to help the Requirement Engineer (RE) in understanding a goal expressed in an informal manner and in reformulating it formally. A goal expresses a requirementthat the system shall fulfil.

• Situation : Goal

To attain this objective following the guidelines provided by the chunk, it is necessary to start with a goal which  has been elicited before in the RE process. This goal is expressed in an informal manner.
 

•  Intention : Elicit a goal with linguistic strategy.

The intention is to transform an informal expression of a goal into a formal one and therefore, to help eliciting a new goal. A linguistic approach defining a goal  as a verb with associated semantic functions  is used  to support this elicitation.

• Graphical Representation :

Description :

As depicted in the graphical representation of the chunk, the body of the chunk is a plan contxt which suggests to proceed in three steps as follows:
The RE shall identify first the class in which the given goal G belongs <(Goal G), Identify the class of the goal G>. For this, he/she uses the goal hierarchie presented below. Then, the RE selects the goal template attachet to the identified class of goals <(Class of goal G), Select a class goal template>. And finally, he/she re-formulates the goal with a statement mathching the selected goal temlate <(Goal G, Goal template), Re-formulate the goalG according to the template>.

The underlying linguistic approach of this chunk is based on the three following assumptions :

 
1.  A  goal is formalised as a verb followed by parameters, each parameter having a semantic function like below :
Object( Obj): The entity/entities or goal(s) affected by the goal. The object exists prior to the goal's achievement and may be modified or
suppressed by it.
Result (Res): The entity/entities or goal(s) which are effected by the goal, which result from its achievement. As opposed to the object case, the entities/goals of the result case do not exist prior to the goal, or they exist only in abstract form and are made concrete as a result of the goal's achievement.
Source(So) : The starting point (information source or physical place) of the goal. This case implies movement.
Direction (Dir): The terminal point of the goal. This is the opposite of the source case.
Reference (Ref): The entity with regard to which an action is performed, or state is attained or maintained
Manner (Man): specifies the way in which the goal is to be achieved.
Means (Mea): specifies the entity (tool...) by means of which the goal is to be achieved.
Quality (Qual): a quality which is to be attained or preserved.
Beneficiary (Ben): the person or group in favour of whom the goal is to be achieved.
Location(Loc): situates the goal in space. This case implies no movement, or movement within the same location.
Time(Time): situates the goal in time.
 
2.   A taxonomy of verbs can be defined and organised in a hierarchical manner. This taxonomy is constructed  considering in one hand, the semantics of the verbs and on the other hand, their semantic functions.The hierarchy is presented in the figure below.  As shown in the figure, the first level of the hierarchy distinguishes between maintenance and evolution goals. The former refer to static verbs (e.g remain.....) whereas the latter are verbs expressing dynamics (e.g become, achieve....). Evolution goals are further refined between process goals (e.g create...) and state change goals (e.g become....). Process goals encompass intellectual activities (e.g knowledge goals) and performance (action goals) etc..
 

3.  Every class of the hierarchy may be characterised by a specific set of semantic functions. In other words, a goal template can be defined for each class of verbs in the hierarchy. This is useful because all the possible parameters of a verb statement are not holding for every goal. For example, the verb template  for  "remain" is

remain[Qual, (Ref),  (Location),(Time)].

This template means that the verb "remain" may be  followed by four parameters, namely quality (which is mandatory) and  referent, location and time which are optional.  It shall be noticed that the same verb may appear several times in the hierarchy because it has several meanings. This is the case for the verb "keep" that is attached to two different nodes of the hierarchy and has two different goal template, one for each node. The table below associates to each class of goals of the hierachy shown above the corresponding goal template.

table
 

Example

• Type : Atomic

 
 
• Aggregates :
Elicit goal/scenario couples following the CREWS-l'Ecritoire approach
 
• Origin : CREWS-L'Ecritoire approach
Centre de Recherches en Inforamtique,
Université de Paris 1 - Panthéon-Sorbonne

N. Prat, Goal formalisation and classification for requirements engineering. Proceedings of the Third International Workshop on Requirements Engineering: Foundations of Software Quality REFSQ’97, Barcelona, pp. 145-156, June 1997.

 
• Tutorial Support : The process is supported by a software tool called L'Ecritoire.

 
• Reuse context :
• Application Domain : Information Systems, Human Computer Interfaces, Socio-Technical Systems, Business Processes
• Design Activity : Requirements Elicitation
• Intention : Formulate system requirements