Table 1: K-tree Test Configurations Table 2: Symbols for Results Figure 6: Purity Versus Dimensions Table 3: A: Unmodified K-tree, TF-IDF Culling, BM25 Figure 7: Entropy Versus Dimensions Table 4: B: Unmodified K-tree, Random Indexing, BM25 + LF-IDF 6.1 INEX Results The INEX XML Mining track is a collaborative evalu- ation forum where research teams improve approaches in supervised and unsupervised machine learning with XML documents. Participants make submissions and the evaluation results are later released. The RI K-tree in configuration E performs on aver- age at a comparable level to the best results submitted to the INEX 2008 XML Mining track. The top two results from the track had a micro purity of 0.49 and 0.50. These are not average scores for the approaches but the best results participants found. The RI K-tree in configuration E had a maximum micro entropy of 0.55. This is 10% greater than the INEX submissions. Table 5: C: Unmodified K-tree, Random Indexing, BM25 ID K-tree Representation A Unmodified TF-IDF Culling, BM25 B Unmodified RI, BM25 + LF-IDF C Unmodified RI, BM25 D Modified RI, BM25 + LF-IDF E Modified RI, BM25 Symbol Meaning α Average Micro Entropy β Standard Deviation of α γ Average Micro Purity δ Standard Deviation of γ Dimensions α β γ δ 100 2.6299 0.0194 0.3981 0.0067 200 2.4018 0.0207 0.4590 0.0085 400 2.2762 0.0263 0.4814 0.0093 800 2.2680 0.0481 0.4768 0.0155 1000 2.2911 0.0600 0.4703 0.0192 2000 2.3302 0.0821 0.4569 0.0254 4000 2.3751 0.1103 0.4401 0.0331 8000 2.3868 0.1068 0.4402 0.0300 10000 2.3735 0.1062 0.4431 0.0306 Dimensions α β γ δ 100 3.0307 0.0149 0.3093 0.0045 200 2.9295 0.0206 0.3300 0.0079 400 2.7962 0.0379 0.3648 0.0143 800 2.6781 0.0718 0.3921 0.0236 1000 2.6509 0.0842 0.3959 0.0260 2000 2.6315 0.1262 0.3908 0.0345 4000 2.6380 0.1451 0.3860 0.0356 8000 2.6371 0.1571 0.3844 0.0382 10000 2.6302 0.1540 0.3876 0.0385 Dimensions α β γ δ 100 2.9308 0.0213 0.3337 0.0089 200 2.7902 0.0335 0.3724 0.0126 400 2.6151 0.0417 0.4089 0.0116 800 2.5170 0.0703 0.4238 0.0197 1000 2.5066 0.0858 0.4234 0.0240 2000 2.4701 0.0938 0.4275 0.0258 4000 2.4581 0.0979 0.4261 0.0271 8000 2.4530 0.1139 0.4260 0.0318 10000 2.4417 0.1019 0.4283 0.0283 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 0.32 0.34 0.36 0.38 0.4 0.42 0.44 0.46 0.48 0.5 dimensions average micro purity A B C D E 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 2 2.2 2.4 2.6 2.8 3 3.2 3.4 dimensions average micro entropy A B C D E