Abdul Samad Shibghatullah
92
30052008
4.4.3 Different Event Timing
Different timing in this context means how long the event is such as, 15 minutes LFSO, or 30 minutes LFR. Timing also can affect the decision to reschedule crew. We believe
that the longer the timing is, the harder it is to do crew rescheduling. For example, if a crew happens to come 1 hour late, it is complicated to find an available crew to replace
the late-crew. The easy option is to replace it with standby crew, however this is not our objective. In this research we are trying to find an optimum solution by using the
available crew instead of standby crew. In this research, for every event we create different timings to test the system. The following paragraph discusses the timing for
every event. For lateness events LFSO, LFR, and LFSW, the experiment starts from 15 minutes
late then increases by 5 minute increments until reaching 60 minutes. In the delay event DFSO, and DFSW, the experiment starts from 80 minutes late then increases by 20
minutes increments until 180 minutes. In the UNV event as shown in Table 4.21, the experiment uses 30, 60, 90 and 120 minutes unavailable. For each scenario there are
three different times of occurrence in an hour, at 15, 30 and 45 minutes past the hour.
4.4.4 Different Times of Day
Based on the interviews with bus companies in London as discussed in Chapter Two, traffic is the major cause of UE especially during peak hours. Peak hours are the time
when many vehicles are on the road. We believe that the time of day has influence on crew rescheduling. In this experiment, three different times of day are selected that are
early, midday, and late. Early is between 7 am. to 9 am., midday is between 12 pm. to 2 pm., and late is between 5 pm. to 7 pm. There are two events LFSO which happen at
the same time. The periods of lateness are15 and 20 minutes. The data are selected randomly using the random formula in Microsoft Excel to generate random numbers
and the numbers are used to refer to the duty numbers. The formula is shown below:
RAND the maximum number-the minimum number + the minimum number
Abdul Samad Shibghatullah
93
30052008
Table 4.22: Data LFSO at Different Times of Day
Large Schedule Early
Crew ID Duty No
Sign-On Start Work 1
BS 131 07:32:00 07:47:00
BZ 138 08:39:00 08:54:00
Midday AZ
102 13:20:00 13:35:00 CF
144 14:06:00 14:21:00 Late
BJ 112 16:08:00 16:23:00
BM 115 16:27:00 16:42:00
Medium Schedule Early
Crew ID Duty No
Sign-On Start Work 1
U 221 7:00:00
07:15:00 AB 228
9:28:00 09:43:00
Midday AK 237
13:13:00 13:28:00
AP 242 14:41:00
14:56:00 Late
AW 249 17:29:00
17:44:00 AX 250
17:43:00 17:58:00
Small Schedule Crew ID
Duty No Sign-On
Start Work 1 Early
F 573 08:17:00
08:32:00 I 576
08:56:00 09:11:00
Midday K 578
11:56:00 12:11:00
L 579 12:26:00
12:41:00 Late
T 587 17:37:00
17:52:00 U 588
18:37:00 18:52:00
The maximum number is the total number of duties at different times of day and the minimum number is 1. For example, for a midday time of medium schedule which has
11 duties the formula will look like this:
Abdul Samad Shibghatullah
94
30052008
RAND11-1+1 Table 4.22 shows the selected data for LFSO at different times of day according to the
type of schedule. The full data for the experiment is shown in Appendix F.
4.5 Undertaking the Experiments
Kategori