HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Blogs
Blog

Account for Uncertainty

NO RATINGS
View Comments: Oldest First|Newest First|Threaded View
Battar
User Rank
Platinum
2 Methods
Battar   11/12/2013 9:22:14 AM
NO RATINGS
Two equivalent methods to reduce uncertaincy:

1: Take a measurement from several sensors and average them

2: Take several measurements from one sensor and average them.

SherpaDoug
User Rank
Gold
Real measurement errors
SherpaDoug   11/13/2013 9:27:38 AM
NO RATINGS
Real errors are rarely Gaussian.

Nancy Golden
User Rank
Platinum
Uncertainty in Measurements
Nancy Golden   11/13/2013 10:06:48 AM
NO RATINGS
Great article Jon - it is important to understand uncertainty in measurements so that you can understand whether or not a reading is really within tolerance. Understanding the tolerance that is acceptable (range of acceptable readings due to measurement uncertainty not only of test equipment but also the device under test) are both important to understand. Repeatability and reproducibility are also factors. Gage R & R is an important tool in this area. Uncertainty is also another reason to make sure your measurement equipment is in calibration. Thanks for the link to the Evaluation of Measurement Data: Guide to the Expression of Uncertainty in Measurement - it is an excellent resource.

Ratsky
User Rank
Platinum
Other factors too!
Ratsky   11/13/2013 1:12:16 PM
NO RATINGS
There are other real-world factors that this analysis ignores.  One is calibration accuracy, another is calibration drift.  A typical calibration cycle is annually.  The day after an instrument is calibrated, the uncertainty can increase because of component aging, ambient temperature effects, etc.  Reality always makes uncertainty increase, often well beyond the simplistic approach of resolution; it's close to the concept of entropy. Resolution puts a LOWER BOUND on uncertainty, but no upper one!  That is the worst part of digital instrumentation, in that it misleads the user to trust the results far beyond what is merited.

tekochip
User Rank
Platinum
Re: Real measurement errors
tekochip   11/14/2013 9:32:41 AM
NO RATINGS
Very true!

 
A slightly different scenario, but I recall a technician sorting 10% resistors, trying to find a handful that were exactly the correct value.  He went through an entire bag and couldn't find any closer than 5%.  So much for Gaussian distribution.  Of course the reason was that all of the closer value resistors were already removed from the sample by the manufacturer to be sold as 5% resistors.


Partner Zone
More Blogs
A San Francisco startup called Otto came out of stealth mode recently and released a dramatic video demonstrating its successful test of a technology for self-driving trucks.
Researchers have found a way to use graphene to cheaply and easily turn dirty water into drinking water.
We shared our list, now Design News readers tell us which artificial intelligence movies they watch again and again.
Researchers have been working on a number of alternative chemistries to lithium-ion for next-gen batteries, silicon-air among them. However, while the technology has been viewed as promising and cost-effective, to date researchers haven’t managed to develop a battery of this chemistry with a viable running time -- until now.
Researchers have simplified the fabrication of the geometric requirements for fluid motion in microrobots for in vivo medical applications.
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Jul 11 - 15, Embedded System Design Techniques™ - Debugging Real-time Embedded Software – Hands on
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7 | 8 | 9 | 10


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Technology Marketplace

Copyright © 2016 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service