A Numerical Exploration of Transient Decay Mechanisms in Water Distribution Systems - Advances in Control and Automation of Water Systems - page 6

tABle 1.2 (Continued)

Model Un-standardized Coefficients Standardized Coefficients t Sig.

Std. Error Beta

2 (Constant) 14.265 29.344 - 0.486 0.632

flow 0.036 0.01 0.469 3.533 0.002

distance -0.004 0.001 -0.52 -3.918 0.001

3 (Constant) 97.523 1.519 - 64.189 0

4 (Constant) 117.759 2.114 - 55.697 0

distance -0.008 0.001 -0.913 -10.033 0

5 (Constant) 14.265 29.344 - 0.486 0.632

flow 0.036 0.01 0.469 3.533 0.002

distance -0.004 0.001 -0.52 -3.918 0.001

Regression Equation defined in stage (1) is accepted, because its coefficients are
meaningful:

Pressure = 28.762 + .031 Flow-.005 Distane + .731 Time (4)

tABle 1.3 Model Summary and Parameter Estimates (Water hammer condition).

Pressure Flow Distance Time Variables

Entered

Variables
Removed

Model Method

(m-Hd) (lit/sec) (m) (sec)

1 time,

distance,
flow(a)

86 2491 3390 0 Enter

86 2491 3390 1

2

88 2520 3291 0

Stepwise
(Criteria:
Probability-of-
F-to-enter <=
.050,
Probability-of-
F-to-remove
>= .100).

90 2520 3190 1

95 2574 3110 1.4

95 2574 3110 1.4

time

95 2574 3110 1.5

95 2590 3110 2

95 2590 3110 2

95.7 2600 3110 2

95.7 2600 3110 3

3 flow,

distance(b)

(a) Remove

95.7 2600 3110 4

95.7 2600 3110 5

4

Forward
(Criterion:
Probability-of-
F-to-enter <=
.050)

95.7 2605 3110 0.5

100 2633 2184 1.3

distance

100 2633 2928 1.3

101 2650 2920 1.4

106 2680 1483 1.4

5

107 2690 1217 1.4

Forward
(Criterion:
Probability-of-
F-to-enter <=
.050)

109 2710 1096 1.4

109 2710 1096 1.4

Flow

110 2920 1000 1.5

a All requested variables entered.
b All requested variables removed.
c Dependent Variable: pressure