Keywords: dejean02a

Next: Evaluation: Up: First Experiment Previous: First Experiment

#### Presentation of the task and evaluation:

In order to evaluate the impact of some parameters used by ALLiS, we conducted some experiments. The task here is the extraction of non-overlapping Noun Phrases (hereafter NP). This problem can be viewed as a problem of categorization using three categories: B-NP, I-NP and O. I-NP means that the element belongs to an NP, a B-NP is used when the current element belongs to an NP and the preceding belongs to another NP. We refer the reader to [Ramshaw and Marcus(1995)] for more information. Here is an example of such a segmentation with these three categories:

> In`O` early`I-NP` trading`I-NP` in`O` Hong`I-NP` Kong`I-NP` Monday`B-NP` ,`O` gold`I-NP` was`O` quoted`O` at`O` $`I-NP` 366.50`I-NP` an`B-NP` ounce`I-NP` .`O`

In order to evaluate the system, we use two measures: precision and recall. The F1-score presented in [van Rijsbergen(1979)] offers a simple way to combine both (in our evaluation, we give the same weight to recall and precision: ).

F=

Next: Evaluation: Up: First Experiment Previous: First Experiment