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person different from the actual user is forced to have
the responsibility when the applicant is impersonated
by another user.
Therefore the goals should be redefined more
precisely. Table 4 shows the added and detailed goals
by risk analysis.
As a result, four new use cases are extracted and a
class Trouble is added to the class diagram as shown
in Figure 4 and 5. Since the responsible user and the
applicant are necessary for the application, it is
possible to correctly grasp the location of
responsibility by certifying the applicant.
Table 4: Added and Detailed Stakeholder’s Goals.
3.7 Verification of Goal Satisfaction
The reservation condition is determined by the
attribute related to "reservation" of the class diagram.
Due to the change of addition of Trouble class, the
condition of "there are no troubles in the reserved
room" is added to the condition. This change is dealt
with by correcting the condition of the action "judge
reservable condition" in Figure 6 with the attribute of
the class.
The satisfaction level of the goal so far could be
confirmed by the existence of elements of the model.
In order to verify the satisfaction of the added and
detailed goals in Table 4, we should consider what
kind of results will be obtained if more than one use
cases are executed during the service. Therefore, from
the use case components extracted so far, using a state
machine diagram, we analyse the influence of the
trouble of the conference room on the state of the
conference room of a certain reservation as shown in
Figure 6.
In Figure 7, every transition event is an
activation of a use case in the use case diagram. The
subject of an event is the applicant or the
administrator as shown in Figure 7. Therefore, the
subject of the use case recognizes the state occurring
as a result of his/her action but cannot recognize it if
it is not the executor. Even in the reserved state, the
information of availability of equipment is
sometimes important, so it is always necessary to
Figure 7: State of a conference room on the other day.
recognize the trouble by notice of conference room
and equipment trouble.
When notifying the trouble from the system, add
a notification action to the action flow in the
corresponding use case description of "Register an
equipment trouble" and "Register a room trouble"
use cases regarding the breakdown of the conference
room. Due to this refinement, the refined goal of the
applicant in Table 4 is satisfied anyway, but it is not
sufficient for the administrator's added goal. Namely,
if it is not possible to use the room in the end, or if
the date of use is near, it is unsatisfactory to the
applicant, and the applicant himself/herself needs to
reserve again.
4 DISCUSSION AND
CONCLUSIONS
Garlan (David Garlan) says, "It is important to treat
uncertainty as a primary concern of software
development." During acquiring requirements for a
desirable system, it is a fact that there are many such
uncertain factors caused by non-functional require-
ments, especially items mentioned in Section II-C).
There are some studies on requirements
acquisition such as Goal-oriented analysis (Chung,
L.). However, it is difficult to treat uncertainty
caused by non-functional requirements about
external activity entity such as hardware, users and
physical things as a primary concern.
In this paper, separating concerns for users and
physical things such as a room or an equipment from
the fundamental scenario lead systematically to
finding new use cases that reduce the risks caused by
them.
In this case, user characteristics give no
influence to a system. However, they often affect the
system architecture and kinds of use cases.
Therefore, the iterative analysis is necessary while
A user cannot actually reserve a
conference room although it is
unavailable.
When there are some troubles, a
user can know the situation
promptly.
The reservation is
guaranteed until the
reserved date.
Student affairs
division staff
When a trouble occurs in the conference room or the
equipment, it can deal with so that inconvenience does
not occur to the user who reserves it.
By using the conference room, when a trouble occurs in
the conference room or the equipment, the location of
responsibility can be grasped correctly.
Goal-Satisfaction Verification to Combination of Use Case Components
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