Information Technology Reference
living room and stands there for over one hour without doing anything absent-
mindedly. In this case, as there is no RFID tag that RFID Reader attached to wrist of
old people can recognize within the scope in the middle of a living room, it is judged
as lonely assuming that there are no activities.
Case 1.1 can be classified into two cases again and reviewing the first case, it is the
case in which no RFID tag information is detected until the expiration of Threshold
time after the aged first started RFID Reader. This can be more cleared if it is
reviewed through Data Model. Fig. 2 expresses the data model for Case 1.1.
Fig. 2. Data Model for Case without any RFID Tag Information
Looking at the figure, it is noted that there was no RFID tag information sensed
from the start time of RFID Reader of the aged until the current time. While renewing
present time repetitively every time, Duration is obtained by deducting starting time
of RFID Reader from present time. And then when value of calculated Duration
becomes bigger than Threshold time, it is judged as lonely situation.
Another case of Case 1.1 is a case in which no RFID tag information is detected
from the time the last RFID tag information was detected to the present. Data Model
expressing such a case is like Fig. 3.
Fig. 3. Data Model for Case with More than One RFID Tag Information
Comparing the two cases, while the first case showed no detection of information
of RFID tag from starting time of RFID Reader to the present, the second case is
different that information of RFID tag come in continuously and from a sudden
moment, information of RFID tag is not detected any more.