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Finally, in the light of the greater contribution, this website will be a part of one of the largest R websites, after following this site for a while.

For those who are using R or interested in this great but free software, is a must!

sem package in R: a sample of transaction cost measurement

A sneak peek of the result of a Structural Equation Model using sem package in R.

I will present in the R User Conference in Warwick next week, is reveal first here.

The following are the codes of ‘sem’ package I used in the paper.

You may also view the code of other packages to run SEM models as well.

##    Measuring Transaction Cost in Supply Chains  ##
##               Pairach Piboonrungroj             ##
##         R useR conference August 2011           ##

# 1. Load data
hoteldata <- read.csv("")

#Input covariance matrix <- cor(hoteldata)

# Have a look at the top of the data
# to check it we import the right one

#Create an object contains correlation matrix of the data for fitting the model in the next step
hotel.cor <- cor(hoteldata)
#  path parameter  start-value
model.TC.1 <- specify.model()
	TC   -> TC1,    gamma1,  NA # measurement item
	TC   -> TC2,    gamma2,  NA
 	TC   -> TC3,    gamma3,  NA
 	TC   -> TC6,    gamma6,  NA
 	TC   -> TC7,    gamma7,  NA
 	TC   -> TC11,   gamma11, NA
 	TC   -> TC13,   gamma13, NA
 	TC1  <-> TC1,	e1,      NA # measurement error
 	TC2  <-> TC2,	e2,      NA
 	TC3  <-> TC3,	e3,      NA
 	TC6  <-> TC6,	e6,      NA
 	TC7  <-> TC7,	e7,      NA
 	TC11 <-> TC11,	e11,     NA
 	TC13 <-> TC13,	e13,     NA
 	TC   <-> TC,    NA,      1


sem.TC.1 <- sem(model.TC.1,, 53)
# print result (fit indices, parameters, hypothesis tests)
# standardised coefficients (loadings)

useR! 2011 full timetable out NOW!

Monday 15th August

Monday timetable.

Opening Mixer, sponsored by CRiSM, 19:30 – 21:00

All conference attendees are welcome to join us for drinks at The Bar on the first floor of the Rootes Building. Beer, wine, non-alcoholic drinks and light snacks will be available for all attendees.

Tuesday 16th August

Tuesday timetable.

Poster Reception, sponsored by Revolution Analytics, 20:00 – 23:00

The evening poster reception will be held at the Panorama Suite on the second floor of the Rootes Building. Beer, wine, non-alcoholic drinks and light snacks will be available for all attendees.

Wednesday 17th August

Wednesday timetable.

Conference Dinner, sponsored by RStudio, 19:30 – 23:00

The conference dinner will be held at the Panorama Suite on the second floor of the Rootes Building. Admission to the conference dinner is via ticket only.

Thursday 18th August

Thursday timetable.


Printed abstracts will not be provided at the conference. Links to individual abstracts are provided in the timetables above and the abstracts for all contributed talks and posters are collected together in theabstract booklet.

Please note that there are three different formats for contributed talks:

useR! Kaleidoscope:
These sessions will give a broad overview of the many different applications of R and should appeal to a wide audience.
useR! Focus Sessions:
These sessions will focus on topics of special interest and may be more technical.
useR! Lightning Talks:
New for useR! 2011, these sessions, with oral presentations of 5 minutes, provide a platform for participants to speak on any R-related topic and should particularly appeal to R newbies.

Information for Speakers, Session Chairs and Poster Presenters

  • Presenters of Kaleidoscope and Focus contributed talks, please note that your talk is scheduled for 17 minutes, followed by 3 minutes discussion.
  • Presenters of Lightning talks, please note that your talk is scheduled for 5 minutes, with 1 minute question/transition time. A variation of the pecha kucha and ignite formats will be used, in which you must provide 15 slides to accompany your talk and each slide will be shown for 20 seconds. Slides must be provided in PDF format and sent to by 17:00 GMT, Friday 12 August, 2011.
  • Each useR! Invited Lecture will last 40 minutes, with 5 minutes at the end of the lecture reserved for questions.
  • Technical details: All lecture rooms are equipped with an LCD projector and a computer or laptop that is connected to the internet. Unless speakers require their own laptop for software demonstrations, speakers are expected to ensure that a PDF of their presentation slides is on the computer provided, before the start of their session. For presenters of Lightning Talks, this is achieved by sending the slides in advance as described above; for presenters of other talks, please see the conference assistant in the relevant lecture room to arrange transfer of your slides. Conference assistants will be available in the lecture rooms at least 10 minutes before the program starts each day and at least 10 minutes before the program recommences after each coffee or lunch break. Please arrive well before the start of your session and introduce yourself to the Session Chair. During your talk, please look out for the countdown cards that the Chair will use to signal that your time is coming to a close.
  • Session Chairs: Please check the News Board in the main atrium for any changes to your session. Please arrive well before the start of your session to meet the speakers and ensure that they have a PDF of their slides on the room computer. Countdown cards will be provided to help you keep the speakers to time. If we are aware that a speaker is missing up to 2 hours prior to the relevant session, then the other talks will be brought forwards and a notice placed on the News Board, otherwise can we please request that Chairs keep to the timetable, and in the event of a missing speaker, advise the audience to go to an alternative talk.
  • For those preparing posters, the poster boards can accommodate posters of size A0 (Portrait) or A1 (Landscape). Poster presenters should arrive at least 15 minutes prior to the start of the poster session to put up their poster (presenters can access the venue from 19:00). Regular posters will have allocated boards as numbered in the schedule; late-breaking posters can be put up on any unnumbered board. Presenters should stay in the vicinity of their poster for the first hour of the session. Please take down your poster at the end of the session; if you are unable to stay until the end (23:00) remaining posters will be removed and can be retrieved from the registration desk the next day.

Source:  The Official R users Conference 2011
PS. My abstract can be found here

useR Conference 2011 – Timetable

Next month I will have a chance to present how I use R to conduct a structural equation model in my thesis to the expeRts. And now the tentative timetable was just released.
Similar to EurOMA, I will be the last on the first day, just before the dinner.

Here is the link for the timetable.

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