Using chaos to improve measurement precision

2002 ◽  
Vol 3 (1) ◽  
pp. 47 ◽  
Author(s):  
Bin HE
2017 ◽  
Vol 54 (6) ◽  
pp. 867-884 ◽  
Author(s):  
Garrett A. Johnson ◽  
Randall A. Lewis ◽  
Elmar I. Nubbemeyer

To measure the effects of advertising, marketers must know how consumers would behave had they not seen the ads. The authors develop a methodology they call “ghost ads,” which facilitates this comparison by identifying the control group counterparts of the exposed consumers in a randomized experiment. The authors show that, relative to public service announcement and intent-to-treat A/B tests, ghost ads can reduce the cost of experimentation, improve measurement precision, deliver the relevant strategic baseline, and work with modern ad platforms that optimize ad delivery in real time. The authors also describe a variant, “predicted ghost ad” methodology, which is compatible with online display advertising platforms; their implementation records more than 100 million predicted ghost ads per day. The authors demonstrate the methodology with an online retailer's display retargeting campaign. They show novel evidence that retargeting can work: the ads lifted website visits by 17.2% and purchases by 10.5%. Compared with intent-to-treat and public service announcement experiments, advertisers can measure ad lift just as precisely while spending at least an order of magnitude less.


2012 ◽  
Vol 241-244 ◽  
pp. 623-626
Author(s):  
Cheng Xun Bei ◽  
Dan Dan Wu ◽  
Jian Xin Peng

One method called “low-order digit decided by high-order digit” is introduced to be applied to equilibrate AC electric bridge with two adjustable parameters frequently encountered in college physics experiment. The full verification of this method is discussed intuitionally. It is indicated that one can eliminate some disturbance of noise and improve measurement precision by using this method.


2013 ◽  
Vol 655-657 ◽  
pp. 714-717
Author(s):  
Zhigang Di ◽  
Chun Rong Jia ◽  
Min Kun Wang ◽  
Jing Xuan Zhang

To meet the requirement of fiber current transformer, special display instrument was deigned. SCM and advanced signal process technology were adopted in the instrument, so that the output voltage signal of low voltage terminal can be utilized by instrument to display measured busbar current value real-time. Besides, section linearization and distinguish calibration methods were adopted to improve measurement precision of display instrument. The experiment results indicated that this instrument has virtues of reliability, high precision and low cost, importantly, it can come up to the 0.2 standard. So we can draw a conclusion that this instrument can meet the industrial requirement for display instrument.


2014 ◽  
Vol 716-717 ◽  
pp. 998-1001
Author(s):  
Sheng Lin ◽  
Ling Xuan Zhang ◽  
Ji Ming Shao ◽  
Chong Feng Zhang

The calibration error of a calibration machine will affect the precision of the six-axis force sensor directly. Aiming at the calibration machine with three force sources, calibration errors of the six-axis force sensor for docking system are analyzed to improve measurement precision. The loading position error and angle error of loading axis are researched on alternatively. The error in the calibration direction and the additional error in other directions are studied on. Analysis results will provide important reference for calibration of the six-axis force sensor.


2009 ◽  
Vol 63 (5) ◽  
pp. 544-548 ◽  
Author(s):  
Yun Chen ◽  
Wenliang Chen ◽  
Zhenzhi Shi ◽  
Yue Yang ◽  
Kexin Xu

Near-infrared (NIR) spectroscopy has been widely used in many industrial applications. It also has tremendous potential for trace element detection and noninvasive human physiological measurements. In NIR spectroscopy, however, the measurement precision is often dependent on temperature, measurement position, and sample status. In order to improve measurement precision, a method using spectral information at a reference wavelength is developed in this paper. Based on the displacement effect between solvent and solute molecules in a solution, the signal at the reference wavelength is used as an internal reference to correct the spectrum of the sample under test. As an example, the spectra of glucose aqueous solutions under different temperatures are measured, and our method for eliminating the temperature disturbance is evaluated. The experimental results obtained show that the relative error of glucose concentration prediction is 330% per degree before the spectrum correction. After the correction, the relative error is reduced to 5.12%, and the error is no longer dependent on temperature. As the displacement effect can be found commonly in various solutions, the method described in this work may be used to improve the accuracy of spectral analysis of many other solutions.


2011 ◽  
Vol 474-476 ◽  
pp. 852-857
Author(s):  
Jian Wen ◽  
Lei Zhou ◽  
Chun Zhang ◽  
Tong Fen Liang

A combined coordinate measuring mechanical arm (CCMMA) was developed to test the operational ability of astronaut in the EVA spacesuit. The equipment measures the space region coordinates of the astronaut’s hand-reach while forces act on a handle. The homogeneous transformation equations of CCMMA are established based on Modified Denavit-Hartenberg (MDH). Measurement error was analyzed and distance error model of CCMMA was set up to improve measurement precision. The improved genetic algorithm is applied to the identification of CCMMA structure parameters. The calibration experiment of CCMMA was carried out using such model and algorithm. The result showed that with identification, the repeatability and length measurement precision were improved by 5.38 and 3.11 times respectively.


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