Unni Cathrine Eiken February 2005
Unni Cathrine Eiken February 2005 Unni Cathrine Eiken February 2005
3.6 Evaluation of the data set The data set created by the extraction process consisted of 195 elementary predicate-argument structures in its raw form. The original EPAS list was not directly applicable for the next parts of the project. Not all of the extracted structures on the list were suitable for further analysis. Some of the EPAS were not given an optimal analysis (for my purposes) by the grammar, some were irrelevant for the later analysis and some were not extracted correctly from the MRS by the Perl script. The dataset was post-edited to achieve a set of EPAS that did not include erroneously extracted or undesired structures. With such a small collection of structures as is the case in this project, the inclusion of only a few incorrect structures would be likely to skew the subsequent analysis and possibly produce false results. In the following, I will briefly outline some of the reasons why the EPAS list included incorrect structures and describe how the list was revised. 3.6.1 Errors from the grammar Some of the undesired structures in the original EPAS list were directly caused by characteristics in the NorGram grammar. In the original EPAS list, there were for instance several structures of the type exemplified by (3-18): (3- 18) a. verbal predicate, nominal argument b. preposition, verbal predicate, nominal argument These structures should preferably have been combined into one EPAS. The example in (3-19) below shows a concrete instance from the EPAS list and is analogous to several other instances: (3- 19) a. bo, Anne live, Anne b. i, bo, studentkollektiv in, live, student housing The structure is extracted from the following sentence from the text material: 52
(3- 20) Anne Slåtten bodde i et studentkollektiv utenfor Førde sentrum. Anne Slåtten lived in student housing outside central Førde. As example (3-20) shows, these structures originate from sentences featuring a verb with an adverbial complement. The adverbial is realised as a prepositional phrase where the preposition is selected by the verb. It would have been expected that sentences such as Anne bodde i et studentkollektiv (Anne lived in student housing) would result in one EPAS with the entity studentkollektiv somehow realized as the structure’s argument 2. Instead, the MRS structure of this and other similar sentences did not provide the necessary link between the verb as predicate and studentkollektiv as the second argument. When discussing this problem with the developers of the grammar, the source of the obstacle was easily identified. In the grammar, the verb bo (live) existed as an intransitive verb, not allowing for an adverbial complement to be analysed as required to produce the desired EPAS. In order to allow for this and similar sentences with the verb bo to produce one EPAS with the correct relationship between the predicate and its arguments, the entry for bo was altered. A solution which allows for an arbitrary preposition was favoured, instead of creating a new template that specifies the possible following prepositions. Analysing the sentence above with the revised grammar produces structures of the following type: (3- 21) bo, Anne, studentkollektiv live, Anne, studenthousing The same phenomena was observed for a few other verbs with prepositional phrases as complements, such as gjemme i (hide in) and observere i (observe in). In these instances, the structures were manually edited. 3.6.2 Irrelevant structures Some of the structures that were extracted correctly from the text collection, were simply removed in the final post-editing of the EPAS list. These structures were not directly relevant for the later analysis process and would not contribute with any valuable information for the 53
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(3- 20)<br />
Anne Slåtten bodde i et studentkollektiv utenfor Førde sentrum.<br />
Anne Slåtten lived in student housing outside central Førde.<br />
As example (3-20) shows, these structures originate from sentences featuring a verb with an<br />
adverbial complement. The adverbial is realised as a prepositional phrase where the preposition<br />
is selected by the verb. It would have been expected that sentences such as Anne bodde i et<br />
studentkollektiv (Anne lived in student housing) would result in one EPAS with the entity<br />
studentkollektiv somehow realized as the structure’s argument 2. Instead, the MRS structure of<br />
this and other similar sentences did not provide the necessary link between the verb as predicate<br />
and studentkollektiv as the second argument. When discussing this problem with the developers<br />
of the grammar, the source of the obstacle was easily identified. In the grammar, the verb bo<br />
(live) existed as an intransitive verb, not allowing for an adverbial complement to be analysed as<br />
required to produce the desired EPAS. In order to allow for this and similar sentences with the<br />
verb bo to produce one EPAS with the correct relationship between the predicate and its<br />
arguments, the entry for bo was altered. A solution which allows for an arbitrary preposition was<br />
favoured, instead of creating a new template that specifies the possible following prepositions.<br />
Analysing the sentence above with the revised grammar produces structures of the following<br />
type:<br />
(3- 21)<br />
bo, Anne, studentkollektiv<br />
live, Anne, studenthousing<br />
The same phenomena was observed for a few other verbs with prepositional phrases as<br />
complements, such as gjemme i (hide in) and observere i (observe in). In these instances, the<br />
structures were manually edited.<br />
3.6.2 Irrelevant structures<br />
Some of the structures that were extracted correctly from the text collection, were simply<br />
removed in the final post-editing of the EPAS list. These structures were not directly relevant for<br />
the later analysis process and would not contribute with any valuable information for the<br />
53
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