Sigmoid units-artificial intelligence, Computer Engineering

Sigmoid units - Artificial intelligence

Remember that the function inside units take as input the weighted sum, S, of the values coming from the units associated to it. The function inside sigmoid units calculates the following value that given a real-valued input S:

2090_Sigmoid units.png

Where e is the base of natural logarithms, e = 2.718...

When we plot the output from sigmoid units given several weighted sums as input, it seems remarkably like a step function:

 

841_Sigmoid units1.png

Certainly, getting a differentiable function which seems like the step function was the main point of the exercise. Definitely, not only is this function differentiable, but the derivative is fairly expressed simply in terms of the function itself:

1259_Sigmoid units2.png

Notice that the output values for the σ function range between but never make it to 1and 0. This is because e-S is never -ve, and the denominator of the fraction tends to 0 as S gets very large  in the -ve direction, and tends to 1 as it gets very large in the +ve direction. This tendency happens quickly: the middle ground between 0 and 1 is hardly ever seen because of the sharp (near) step in the function. Because of it seems like a step function, we may think of it firing and not-firing as in a perceptron: if a positive real is input, the output will normally be close to +1 and if a negative real is input the output will normally be close to -1.

Posted Date: 10/2/2012 6:16:27 AM | Location : United States







Related Discussions:- Sigmoid units-artificial intelligence, Assignment Help, Ask Question on Sigmoid units-artificial intelligence, Get Answer, Expert's Help, Sigmoid units-artificial intelligence Discussions

Write discussion on Sigmoid units-artificial intelligence
Your posts are moderated
Related Questions
Explain about the e-commerce over extranets. Extranets are regarding “joining up” the supply chain-suppliers, distributors, resellers and customers are enabling business-to bus

FTP FTP (File Transfer Protocol) is the protocol used on the Internet for sending files and is usually used for uploading / downloading files (web pages) to and from servers. T

Selective set The selective-set operation sets to 1 bits in register A where there can corresponding 1's  in  register  B.  It  does  not  affect  bit  positions  which  have

Explain the Fundamentals of C Programming? The C is a general purpose structured programming language. The C was developed and first implemented by the Dennis Ritchie at Bell L

What are the different ways synchronize between two clock domains? The following section describes clock domain interfacing one of the biggest challenges of system-on-chip (SOC

What are the special features of Direct RDRAM? It is a two channel Rambus It has 18 data lines intended to transfer two bytes of data at a time There are no divide

What are the address-sequencing capabilities required in a control memory? i. Incrementing the control address register ii. Unconditional branch as specified by address fiel

INSERT OPERATION The insert operation inserts a new value into a set of bits. This is done by first masking bits and then O ring them with required value. For illustration, sup

Describe the operation of voltage to frequency ADC. Ans: A voltage-to-frequency converter i.e. VFC is an oscillator that frequency is linearly proportional to a control volt

Define Protocol. It is a set of rules that are followed by interconnecting computers and terminals to make sure the orderly transfer of information