Dear Sirs,
When a table graph shows both positive and negative relationships between the input and output, how could we specify the polar (+/-) of the causual link that interlocks the multiplier and its multipliee (a normal constant) ? I think it would be hard to tell whether the feedback structure is of positive or negative one.
Thank you.
Monte
Specifying the type of feedback structure
feeedback structure
Hi
I use two ways to deal with that problem.
One way is just to leave things like they are, and draw a
loop with no sign in it, meaning that the loop can be positive or negative.
If one wants absolutely to know when the loop is negative or positive the solution is to replace the arrow that can be positive or negative by two arrows one always positive and one always negative if possible, and then you have two loops and arrows that are working one at a time.
Of course you have to find when the arrow is positive and when it is negative to be able to tell the model which arrow will be working.
So you can use an if then else like
Y = if then else (condition positive,F(x),G(X)) where F is the positive function and G the negative one.
Calculating the condition positive may be in certain cases complex.
Regards.
JJ
I use two ways to deal with that problem.
One way is just to leave things like they are, and draw a
loop with no sign in it, meaning that the loop can be positive or negative.
If one wants absolutely to know when the loop is negative or positive the solution is to replace the arrow that can be positive or negative by two arrows one always positive and one always negative if possible, and then you have two loops and arrows that are working one at a time.
Of course you have to find when the arrow is positive and when it is negative to be able to tell the model which arrow will be working.
So you can use an if then else like
Y = if then else (condition positive,F(x),G(X)) where F is the positive function and G the negative one.
Calculating the condition positive may be in certain cases complex.
Regards.
JJ
feedback structure
Hi
You can have in the same lookup a positive and a negative influence at the same time.
Here is joined two models:
one with the loop with nothing in it with a negative and positive lookup, and one with two loops that gives the same result than the first but with the positive and negative loop splitted into two loops one negative and the other positive.
Regards.
You can have in the same lookup a positive and a negative influence at the same time.
Here is joined two models:
one with the loop with nothing in it with a negative and positive lookup, and one with two loops that gives the same result than the first but with the positive and negative loop splitted into two loops one negative and the other positive.
Regards.
- Attachments
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- positive_negative.mdl
- (2.59 KiB) Downloaded 329 times
feedback structure
second model joined
- Attachments
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- positive_and_negative.mdl
- (3.34 KiB) Downloaded 318 times
feed back structure
there was a mistake in the polarity of one of the arrow
joined the corrected model
joined the corrected model
- Attachments
-
- positive_and_negative.mdl
- (3.34 KiB) Downloaded 318 times