Adding momentum - sigmoid units, Computer Engineering

Adding Momentum - Sigmoid units:

However imagine a ball rolling down a hill as it does so then it gains momentum in which its speed increases and it becomes more difficult to stop. Alternatively as it rolls down the hill towards the valley floor as the global minimum, then it might occasionally wander into local hollows. Moreover,, there it may be that the momentum it has obtained stays it rolling up and out of the hollow and back on track to the valley floor. 

Hence the crude analogy describes one heuristic technique for avoiding local minima that called adding momentum, funnily enough. Thus the method is simple as: now for each weight remember as the previous value of Δ that was added on to the weight in the last epoch. Rather then, where updating that weight for the current epoch, add on a little of the previous Δ. Now how small to make the additional extra is controlled through a parameter α that's called the momentum which is set to a value between 0 and 1. 

Alternatively to see why this might help bypass local minima so note there that if the weight change carries on in the direction it was going in the previous epoch and then the movement will be a little much more pronounced in the current epoch. Thus this effect will be compounded as the search continues in the same direction. Where the trend finally reverses so then the search may be at the global minimum case there it is hoped that the momentum won't be enough to take it anywhere other than where it is belongs. Conversely the search may be at a fairly narrow local minimum. So next there in this case, even though the back propagation algorithm which dictates Δ will change direction then it may be that the additional extra from the previous epoch as the momentum may be enough to  counteract this effect for a few steps. Then we can saythese few steps may be all that is utilised to bypass the local minimum.

Posted Date: 1/11/2013 7:23:47 AM | Location : United States







Related Discussions:- Adding momentum - sigmoid units, Assignment Help, Ask Question on Adding momentum - sigmoid units, Get Answer, Expert's Help, Adding momentum - sigmoid units Discussions

Write discussion on Adding momentum - sigmoid units
Your posts are moderated
Related Questions
HOW TO WORK IN DREAMWEAVER? How and Where to open Dreamweaver? Step 1: Click on Start Step 2: Select Program Step 3: Select Macromedia Dreamweaver Step 4: Click on

No C don't have circular shift operator. (Part of the reason why that is the sizes of C's types aren't precisely described----but a circular shift makes most sense when applied to

Q. Instruction set for IA - 64 architecture? Instruction set: Architecture gives instructions for multimedia operations as well as floating point operations. Itanium supports

The number and nature of registers is a major factor which distinguishes among computers. For illustration, Intel Pentium has about 32 registers. A number of these registers are sp

Question: (a) Program instructions and data are brought into memory first, in order to be executed. Explain how the CPU enables an instruction to be executed? (b) Describe

A weighted resistor digital to analog converter using N bits requires a total of ? Ans. Digital to analog converter, a weighted resistor using N bits needs a total of N precisi

What are the Kernel threads Kernel threads are supported directly by the operating system .Thread creation; scheduling and management are done by the operating system. Thus the

Classic form of OLAP is called as MOLAP and it is often known as OLAP. Simple database structures like time period, product, location, etc are used. Functioning of each and every d

Question : 1. Define the term Color Depth. Explain how it impacts on image quality and file size. 2. Using an appropriate example, explain when you will consider using GIF