[R] partial association model

[0034058@fudan.edu.cn]

my last post was filtered,so I post it again with another title.

If I do not make a mistake,the partial association model is an 
extension of log-linear model.I read a papers which gives an example 
of it.(Sloane and Morgan,1996,An Introduction to Categorical Data 
Analysis,Annual Review of Sociology.22:351-375) Can R fit such partial 
association model?

ps:Another somewhat off-topic question.What's the motivations to use 
log-linear model?Or why use log-linear model?I learn the log-linear 
model butI still do not master the the advantage of the model.thank 
you!