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Wednesday, March 25, 2009

Power of Control Charts




This spring SCMG meetings have my new presentation "Power of Control Charts" scheduled:


I plan to present this as a workshop, which will be about the following:

- What is the Control Chart? - A little bit of theory and history.
- Where the Control Chart is used: Review of some systems performance tools on a market that built and use control charts.
- How SEDS uses that - MASF charts vs. SPC ones; long gallery of already published charts in the CMG papers plus some new ones with explanations how to read them.
- How to build Control chart: using Excel for interactive analysis and
R to automate the control charts generating with live demonstration of the technique.

Here is the last part of the presentation:
R script (http://www.r-project.org/) to build monthly profile of some real Unix file system space utilization in form of a monthly Control Chart.

The following are the input data (CSV file) and R script.

day,Current Month Data,UpLimit,Mean,LowLimit
1,0.45,0.54,0.42,0.31
2,0.45,0.54,0.42,0.31
3,0.45,0.54,0.42,0.31
4,0.45,0.54,0.42,0.31
5,0.45,0.54,0.42,0.31
6,0.45,0.53,0.43,0.32
7,0.45,0.54,0.43,0.32
8,0.45,0.54,0.43,0.32
9,0.45,0.53,0.43,0.33
10,0.45,0.53,0.43,0.33
11,0.45,0.53,0.43,0.33
12,0.72,0.53,0.43,0.33
13,0.72,0.53,0.43,0.33
14,0.72,0.53,0.42,0.32
15,0.45,0.53,0.42,0.32
16,0.45,0.55,0.43,0.31
17,0.45,0.55,0.44,0.33
18,1.00,0.54,0.44,0.33
19,0.84,0.54,0.44,0.33
20,0.84,0.54,0.44,0.34
21,0.84,0.54,0.44,0.34
22,,0.54,0.44,0.34
23,,0.52,0.44,0.36
24,,0.52,0.44,0.36
25,,0.51,0.43,0.36
26,,0.66,0.46,0.26
27,,0.66,0.46,0.25
28,,0.62,0.45,0.28
29,,0.62,0.45,0.28
30,,0.54,0.43,0.32
31,,0.54,0.43,0.32

## R script to plot control chart to jpeg agaist CSV input - I.Trubin 2009 
jpeg("C://CMG/2009/cchrt.jpg")
cchrt <- read.table('C:/Users/TIgr/CMG/2009/cchrt.csv', header=T, sep=",")
plot (cchrt[,1],cchrt[,2],type="l",col="black",ylim=c(0,1),lwd=2,ann=F)
points (cchrt[,1],cchrt[,3],type="l",col="red", ylim=c(0,1),lwd=1,ann=F)
points (cchrt[,1],cchrt[,4],type="l",col="green",ylim=c(0,1),lwd=1,ann=F)
points (cchrt[,1],cchrt[,5],type="l",col="blue", ylim=c(0,1),lwd=1,ann=F)
mtext("Space Utilization",side=2, line=3.0)
mtext("days of month", side=1, line=3.0)
mtext("CONTROL CHART", side=3, line=1.0)
legend(9,0.3,c("Current Month","UpperLimit","Mean","LowerLimit"),
col=c("black","red","green","blue"),lwd=c(2,1,1,1),bty="n")
dev.off()

Result is in the picture at the beginning of the posting.

Welcome to my presentation!

(Other examples posted here: Near-Real-Time IT-Control Charts )