I'm not sure what to recommend, as I am unfamiliar with LDR's. These people http://www.scribd.com/doc/30226030/L...dent-Resistors suggest that a "typical" LDR's resistance is related to intensity by something like R=A/L where L is light intensity and A is a constant. If L is directly related to E, then maybe a function of the form R=sum(Ai/V^i) might be suitable.

You might search further in the literature on LDR's and see what function types others have used to correlate the resistance of an LDR.