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multivariate poisson hidden markov models for analysis of spatial ...

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Figure 6.3 illustrates the evolution <strong>of</strong> the loglikelihood, the AIC and the BIC <strong>for</strong><br />

different components ( k =1,…,7) <strong>of</strong> the local independence <strong>multivariate</strong> Poisson model.<br />

This figure demonstrates that the AIC selects 6 components whereas the BIC selects 5<br />

components. There<strong>for</strong>e, in this case, the model with fewer components is selected <strong>for</strong><br />

interpretation.<br />

-600<br />

-650<br />

-700<br />

Loglikelihood<br />

-750<br />

-800<br />

-850<br />

-900<br />

-950<br />

-1000<br />

1 2 3 4 5 6 7<br />

k (the number <strong>of</strong> components)<br />

Loglikelihood AIC BIC<br />

Figure 6.3: Loglikelihood, AIC and BIC against the number <strong>of</strong> components <strong>for</strong> the<br />

local independence <strong>multivariate</strong> Poisson finite mixture model<br />

Figure 6.4 illustrates the optimal value <strong>of</strong> the mixing proportions <strong>for</strong> the range <strong>of</strong><br />

<strong>models</strong> used (values <strong>of</strong> k from 2 to 7). It can be seen that there is one large component<br />

and the rest are small components in all <strong>models</strong>. In fact, the mixing proportions tend to<br />

fluctuate over the different component solutions.<br />

116

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