Internet-based intensive product design platform for ... - GRACO
Internet-based intensive product design platform for ... - GRACO
Internet-based intensive product design platform for ... - GRACO
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12<br />
Table 3<br />
Constraints of support-pairs with rotative movement<br />
Constraints Values<br />
are hidden in weights via Eqs. (3) and (4).<br />
x p<br />
0 ¼ 21:0; W0j ¼ u ð3Þ<br />
o p<br />
0 ¼ 21:0; W0k ¼ u ð4Þ<br />
The global error function as:<br />
E ¼ 1<br />
2N<br />
X N<br />
X L<br />
p¼1 k¼1<br />
d p<br />
k<br />
2 y p<br />
k<br />
2<br />
Weight-adjusted <strong>for</strong>mula as: DW ¼ 2hð›E=›WÞ<br />
Eq. (5) shows the calculating model of the adjusting<br />
weight in the output layer (h represents the learning ratio<br />
and a represents the momentum coefficient).<br />
s p<br />
k<br />
DW p<br />
jk<br />
¼ y p<br />
k<br />
1 2 y p<br />
k<br />
p p<br />
¼ hsk oj DW jk ¼ h XN<br />
p¼1<br />
s p p<br />
k oj d p<br />
k<br />
2 y p<br />
k<br />
W jkðt þ 1Þ ¼W jkðtÞþDW jkðtÞþaDW jkðt 2 1Þ<br />
The <strong>for</strong>mula of adjusting weights of the hidden layer is<br />
shown as Eq. (6)<br />
s p<br />
i<br />
DW p<br />
ij<br />
¼ o p<br />
j<br />
1 2 o p<br />
j<br />
p<br />
¼ hsj x;p i<br />
DW ij ¼ h XN<br />
p¼1<br />
s p p<br />
j xi X L<br />
k¼1<br />
1 0.5 0<br />
Lubrication (LU) Need Any None<br />
Speed (SP) Low Middle High<br />
Load (LD) Low Middle High<br />
Temperature (TP) Low General High<br />
Precision (PR) Low General High<br />
Structure (ST) None General Compact<br />
s p<br />
k W jk<br />
Fig. 5. The BP networks <strong>for</strong> searching support-parts knowledge.<br />
S. Zhou et al. / Knowledge-Based Systems 16 (2003) 7–15<br />
ð5Þ<br />
ð6Þ<br />
Fig. 6. Input interface of constraints on Support-Parts with Rotative<br />
Movement in IPDP.<br />
W ijðt þ 1Þ ¼W ijðtÞþDW ijðtÞþaDW ijðt 2 1Þ<br />
In BP neural networks, the coefficients h and a should be<br />
greater than zero and less than one. The groups of training<br />
samples of BP neural networks should be three to ten times<br />
the number of weights [14].<br />
5.3. An example of knowledge search<br />
As seen earlier, the mathematical model of the ANN is<br />
stated. Here, how to apply the ANN model <strong>for</strong> searching and<br />
retrieving knowledge from the repositories of the IPDP is<br />
discussed. The illustration is <strong>based</strong> on rotative support parts<br />
stated in Section 5.1.<br />
Corresponding to the knowledge function support-parts<br />
with rotative movement shown in Fig. 4, the constraints are<br />
shown in Table 3. The knowledge matched with the function<br />
requirement of the rotative support is the rolling bearing, the<br />
journal bearing and the magnetic bearing. Here, setting the<br />
number of hidden nodes of BP networks at 4, the structure of<br />
Fig. 7. Output interface of result on Support-Parts with Rotative Movement<br />
in IPDP.