Contents Telektronikk - Telenor

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hour
Figure 6 The daily traffic intensity profiles, the quarter-hours being averaged over
ten consecutive working days, each as average of 115 circuit-groups [5]
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May 1985
Aug 1985
Nov 1985
May 1995
Aug 1995
Nov 1995
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Figure 7 Division of the 115 circuit-groups into different peak-hour timings in the
three fortnight measurement rounds: May, August and November 1985 [6]
centrated on these hours only, where a
peak-hour has been discovered in earlier
measurements.
The study object in Helsinki local network
was the 115 circuit-groups in the
Sörnäinen AKE-transit exchange. The
fortnight measurement rounds in quarterhours
lasted daily from 8 a.m. to 10 p.m.
The measurements were carried out in
May, August and November 1985,
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35
36
totalling nearly 600 kEh per round. The
complete study is published in [6].
The study indicated that the total profiles
of the whole exchange, describing sum
profiles of all circuit-groups, were quite
stable, Figure 6. The morning, afternoon
and evening peaks are obvious, and
according to the ElCo about measurement
round for the whole exchange, serving
both business and domestic traffic.
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4
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2
1
When observing separate circuit-groups’
peak-hours, they can be seen to have
morning, afternoon or evening day-time
character, Figure 7.
But when observing one circuit-group in
consecutive rounds, the peak-hour jumps
from one day-time to another between
rounds in 26 % of cases. According to a
study of the primary material in rounds in
August and November, if measured in
full hours, only in five circuit-groups did
(4 %) the peak-hour keep its timing
strictly from one round to another. But
when taking into account the partial
overlappings, too (Figure 6), the percentage
of overlapping circuit-groups increased.
A partial overlapping of three
quarter-hours was in 24, of half-hours in
14, and of one quarter-hour in 15 circuitgroups,
but as many as every second case
remained without overlapping at all.
Thus the average overlapping was (5 x 4
+ 24 x 3 + 14 x 2 + 1 x 15) / 115 =
135 / 115 = 1.17 quarter-hours. The
result is that the probability of finding the
peak-hour from the earlier timing in consecutive
measurement rounds is 1.17/4 =
0.29. Thus the earlier mentioned good
stability of the whole exchange’s traffic
profiles does not help the fact that by circuit-groups
there is a bigger probability
to miss than to hit the peak-hour, when
the measurement is timed according a
preselected time.
5 The representativity of
the average day
The ElCo about the average day is that
the peak-hour of the average day in measurement
round coincides with the peakhours
of the round’s days. If the ElCo
about the average day is valid, the average
day’s peak-hour can be used instead
of the peak-hours of the days in the
round.
The study object in Helsinki local network
was the 115 circuit-groups in the
Sörnäinen AKE-transit exchange. The
fortnight measurement rounds in quarterhours
lasted daily from 8 a.m. to 10 p.m.
The measurements were carried out in
May and November 1985, totalling
nearly 600 kEh per round. The complete
study is published in reference [7].
The study indicated that the average
day’s peak-hour coincides fully with the
peak-hours of zero to six of the round’s
days in May (zero to five in November),
averaging 2.36 (1.93), of the ten possible
days. But when taking into account the
quarter-hourly overlappings, too (Figure