Example multi-layer ann with sigmoid units, Computer Engineering

Example Multi-layer ANN with Sigmoid Units - Artificial intelligence:

We will discuss ourselves here with ANNs containing only 1 hidden layer, as this makes describing the back propagation routine simpler. Notice that networks where you may feed in the input on the left and propagate it forward to get an output are known feed forward networks. Below is such an ANN, with 2 sigmoid units in the hidden layer. The weights have been set arbitrarily between all the units.


2290_Example Multi-layer ANN with Sigmoid Units.png

Notice that the sigma units have been recognized with sigma signs in the node on the graph. As we did with perceptrons, we may give this network an input and determine the output. Also we may look to see which units "fired", for example, had a value closer to 1 than to 0.

Imagine we input the values 10, 30, 20 into the 3 input units, from top to bottom. Then the weighted sum approaching into H1 will be:

SH1 = (0.2 * 10) + (-0.1 * 30) + (0.4 * 20) = 2 -3 + 8 = 7.

Then the σ function is applied to SH1 to give:

σ (SH1) = 1/(1+e-7) = 1/(1+0.000912) = 0.999

[Do not forget to -ve S]. In Simple term, the weighted sum coming into H2 will be: SH2 = (0.7 * 10) + (-1.2 * 30) + (1.2 * 20) = 7 - 36 + 24 = -5

And σ applied to SH2 gives:

σ (SH2) = 1/(1+e5) = 1/(1+148.4) = 0.0067

From this, we may see that H1 has fired, but H2 has not fired. Now we can calculate that the weighted sum put in to output unit O1 will be:

SO1 = (1.1 * 0.999) + (0.1*0.0067) = 1.0996

And the weighted sum put in to output unit O2 will be: SO2 = (3.1 * 0.999) + (1.17*0.0067) = 3.1047

Now the output sigmoid unit in O1 will calculate the output values from the network for O1:

σ (SO1) = 1/(1+e-1.0996) = 1/(1+0.333) = 0.750

and the output from the network for O2:

σ(SO2) = 1/(1+e-3.1047) = 1/(1+0.045) = 0.957

Thus, if this network represented the learned rules for a categorization problem, the input triple (10,30,20) would be categorized into the category related with O2, because this has the bigger output.

Posted Date: 10/2/2012 6:20:49 AM | Location : United States

Related Discussions:- Example multi-layer ann with sigmoid units, Assignment Help, Ask Question on Example multi-layer ann with sigmoid units, Get Answer, Expert's Help, Example multi-layer ann with sigmoid units Discussions

Write discussion on Example multi-layer ann with sigmoid units
Your posts are moderated
Related Questions
what is transform mapping and transaction mapping?

advantages of dda line algoritm

1. What factors should be considered when selecting a digital encoder (line codes)? Briefly mention five of those factors. Use sketches and additional text to describe the followin

write a programme to simulate a train station to automate

Case x, z difference, which is preferable, why? CASEZ : Special version of case statement that uses a Z logic value to signify don't-care bits. CASEX : Special

How do we merge an image from a file to the current image in GIMP? Ans) Use "File then Open as Layers" menu command or just take the file to a window and drop it there. The file w

Q. Benefit of digital versatile disk read only memory? The main benefit of having CAV is that individual blocks of data can be accessed at semi-random mode. So head can be move

We have determined the general architecture and register set of MIPS microprocessor. Our subsequent task is to look at functionality of ALU, the CU and how an instruction is execut

How to use ActiveX Control in .Net ? ActiveX control is a special type of COM component that handles a User Interface. Using ActiveX Control in your .Net Project is even simple