the given scenario by hand. We propose a retrieval
method in order to get similar scenarios or related sce-
narios using the similar information of scenarios.
We assume that scenarios are analyzed based
on the requirements frame in advance. As previ-
ously mentioned in Section 2, the requirements frame
strongly depends on the problem domain. So, if case
structures of verbs are different between two scenar-
ios, we consider that these two scenarios are belong-
ing to different domains each other. If all of the case
structures are same, these scenarios can be classified
into the same domain.
We propose two factors of the similarity between
scenarios. One is related to same system. For ex-
ample, a banking system provides several functions,
withdrawal, deposit, loan, opening account, and so
on. These functions are different each other, but both
active objects, such as customer, bank clerk, ATM,
banking system and inactive objects, such as bank
card, cash, account in common appear in scenarios
specifying behaviors of these functions of the banking
system. The other factor is related to same or similar
behavior. For example, behavior of train seat reser-
vation and that of flight reservation are similar each
other, although these systems are different.
4.1 Similarity of Scenarios by System
If same nouns are used in scenarios, these scenarios
probably specify behaviors of the same system. For
example, “library id,” “e-library system,” and “librar-
ian” appear in different scenarios, these scenarios can
be regarded as scenarios of the same system. On the
basis of the above discussion, we give an equation in
order to measure the similarity of system of scenarios
as below.
Similarity of system between the two scenarios =
theno. of samenounsineventsof thetwoscenarios
thetotal no. of nounsineventsof thetwoscenarios
(1)
As for scenarios in Figure 1 and 2, nouns in the
events of these scenarios are shown in Table 7.
The total number of the nouns is 19 and the same
nouns are “database”, “name” and “room rate.” So
the similarity of system between these two scenarios
becomes
3
19
.
4.2 Similarity of Scenarios by Behavior
If scenario titles have a same verb, these scenario
probably specify similar behaviors. For example, a
scenario whose title is “a customer reserves a train
Table 7: Nouns in the events of Figure 1 and Figure 2.
Scenario nouns
Fig.1 available hotel(s), credit card company,
(credit) card number, database,
membership number, name, (retrieval)
information, reservation number,
(reservation) system, room rate,
status of the card, user
Fig.2 available room, citizen, database, name,
receipt, (reservation) information,
room number, (room) rate,
system, telephone number
seat” and another scenario whose title is “a user re-
serves a flight ticket” can be classified into similar
scenarios from a behavioral viewpoint. However, a
scenario whose title is “a customer purchases a train
ticket” can be classified into similar scenarios with
above ones. So, we think that scenarios are similar if
titles of the scenarios have same verb, but this is not
necessary.
Sequence of events in a scenario represents be-
haviors of users and system. If systems are differ-
ent from each other, nouns in events become differ-
ent, even if events specify similar behaviors. So, we
use corresponding events in the differential scenario.
If two scenarios are similar each other from the per-
spective of behavior,the ratio of corresponding events
becomes high.
On the basis of the above discussions, we give the
second equation in order to measure the similarity of
behaviors of scenarios as shown in below.
Similarity of behavior between the two scenarios =
thenumberof correspondingevents
thetotal numberof eventso f thetwoscenarios
(2)
As shown in Figure 3, the total number of events
is 10+ 9− 7= 12 and the number of the same events
is 7. So, the similarity of behavior between scenarios
of Figure 1 and 2 is
7
12
= 0.58 We consider that two
scenarios whose similarity of behavior is greater than
0.5 are scenarios of similar behaviors.
In order to apply the differential information to
another scenario of reservation of a hotel room, we
also provide a script for application script shown in
Figure 4. Even if there exists a delete command in
a script, event blocks will not be deleted when any
event blocks in an applied scenario do not match with
event blocks in the script. Even if there exists an in-
sertion command in the script, event blocks will not
be inserted when the following event block and the
followed event block are missing in the applied sce-
nario.
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