{
  for (i in 1:n){
    a[i]~dlnorm(0,4);
    b[i]~dnorm(0,0.25);
    c[i]~dbeta(5,17);
  }

  for (j in 1:N){
    for (i in 1:n){
      p[j,i]<-c[i]+(1-c[i])/(1+exp(-1.7*a[i]*(theta[j]-b[i])));
      U[j,i]~dbern(p[j,i]);
    }
    theta[j] ~ dnorm(0,1);
  } 
}