Reasoning Support for Risk Prediction and Prevention in Independent Living 27

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Example 3 Consider results of the evaluation process as in the first graph of Table 8. Two direct observations are available: obs_label(*item*3, −1) and obs_label(*item*2, 0). We set the weight of each arc from Ij to Ih to 5 if sign of Ij is provided by the evaluation process, to 1 otherwise. Possible consistent guesses are represented by three answer sets containing, among others, the following predicates:

S1 = { count_inf l(item4, −1, 5), count_inf l(item4, 0, 1), count_*inf l(item*5, 0, 5),
count_inf l(item2, −1, 5), count_inf l(item2, 0, 2), ilab(item6, 0), ilab(item3, −1), ilab(item4, −1), ilab(item5, 0), ilab(item2, −1)*, ilab(item*1, 0)}
S2 = { count_inf l(item4, −1, 1), count_inf l(item4, −1, 5), count_inf l(item5, 0, 5),
count_inf l(item2, −1, 5), count_inf l(item2, 0, 1), ilab(*item*6, 0),
ilab(item3, −1), ilab(item4, −1), ilab(item5, 0), ilab(item2, −1), ilab(*item*1, −1)}
S3 = { count_inf l(item4, −1, 5), count_inf l(item5, 0, 5), count_*inf l(item*2, −1, 5),
count_inf l(item2, 0, 1), count_inf l(item2, 1, 1), ilab(item6, 0),
ilab(item3, −1), ilab(item4, −1), ilab(item5, 0), ilab(item2, −1)*, ilab(item*1, 1)}
Since the sign of *item*1 has three possible guesses, it is not considered as a result of prediction. All other guesses are coherent in all answer sets, thus result of the prediction task are as illustrated in the second graph in Table 8. In the future, we will investigate additional optimization techniques in order to provide a more accurate qualitative evaluation of all possible consistent labeling. Even though the following reasoning tasks consider only one solution of the prediction task, all solutions are stored for off-line evaluation. In the actual implementation, if there is no total consistent labeling, the solutions that allow to mark a greater number of nodes are taken into account. The way SINDI's knowledge representation model has been conceived suggests us that we can investigate inconsistent subgraphs in order to determine whether they are generated by an