sebastianruder--nlp-progress
Jonathan Kummerfeld
a20d0e0fa6
* Adding additional tasks and results for CCG * Bugfixes and more results * Adding PTB parsing of missing elements
51 行
3.3 KiB
Markdown
51 行
3.3 KiB
Markdown
# Missing Elements
|
|
|
|
Missing elements are a collection of phenomenon that deals with things that are meant, but not explicitly mentioned in the text.
|
|
There are different kinds of missing elements, which have different aspects and behaviour.
|
|
For example, [Ellipsis](https://en.wikipedia.org/wiki/Ellipsis_(linguistics)), Fused-Head, Bridging Anaphora, etc.
|
|
|
|
|
|
### Numeric Fused-Head (NFH)
|
|
FHs constructions are noun phrases (NPs) in which the head noun is missing and is said to be “fused” with its dependent modifier.
|
|
This missing information is implicit and is important for sentence understanding.
|
|
|
|
The Numeric [Fused-Head dataset](https://github.com/yanaiela/num_fh/tree/master/data/resolution/processed)
|
|
consists of ~10K examples of crowd-sourced classified examples, labeled into 7 different categories, from two types.
|
|
In the first type, *Reference*, the missing head is referenced explicitly somewhere else in the discourse, either in the
|
|
same sentence or in surrounding sentences.
|
|
In the second type, *Implicit*, the missing head does not appear in the text and needs to be inferred by the reader or
|
|
hearer based on the context or world knowledge. This category was labeled into the 6 most common categories of the dataset.
|
|
Models are evaluated based on accuracy.
|
|
|
|
Annotated Examples:
|
|
|
|
#### Reference
|
|
|
|
| I | bought | 5 | apples | but | got | only | 4 | . |
|
|
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|
|
| | | | HEAD | | | | NFH-REFERENCE | |
|
|
|
|
#### Implicit
|
|
|
|
| Let | 's | meet | at | 5 | tomorrow | ? |
|
|
| --- | --- | --- | --- | --- | --- | --- |
|
|
| | | | | NFH-TIME | | |
|
|
|
|
|
|
| Model | Accuracy | Paper / Source | Code |
|
|
| ------------- | :-----:| --- | :-----: |
|
|
| Bi-LSTM + Scoring (Elazar and Goldberg, 2019) | 60.8 | [Where’s My Head? Definition, Dataset and Models for Numeric Fused-Heads Identification and Resolution](https://arxiv.org/abs/1905.10886) | [Official](https://github.com/yanaiela/num_fh) |
|
|
| Bi-LSTM + Elmo + Scoring (Elazar and Goldberg, 2019) | 74.0 | [Where’s My Head? Definition, Dataset and Models for Numeric Fused-Heads Identification and Resolution](https://arxiv.org/abs/1905.10886) | [Official](https://github.com/yanaiela/num_fh) |
|
|
|
|
## PTB Traces and Null Elements
|
|
|
|
These are evaluated on section 23 of the Penn Treebank, using a metric defined by Johnson (2002).
|
|
An implementation of the metric is available with the code from [Kummerfeld and Klein (2017)](https://github.com/jkkummerfeld/1ec-graph-parser/tree/master/evaluation).
|
|
|
|
| Model | F-score | Paper / Source | Code |
|
|
| ------------- | :-----:| --- | :-----: |
|
|
| Kato and Matsubara (2016) | 77.8 | [Transition-Based Left-Corner Parsing for Identifying PTB-Style Nonlocal Dependencies](https://www.aclweb.org/anthology/P16-1088) |
|
|
| Kummerfeld and Klein (2017) | 70.6 | [Parsing with Traces: An O(n^4) Algorithm and a Structural Representation](https://aclweb.org/anthology/papers/Q/Q17/Q17-1031/) | [Github](https://github.com/jkkummerfeld/1ec-graph-parser)
|
|
| Johnson (2002) | 68 | [A simple pattern-matching algorithm for recovering empty nodes and their antecedents](https://www.aclweb.org/anthology/P02-1018) | [Code](http://web.science.mq.edu.au/~mjohnson/code/Restorer.tbz) and [README](http://web.science.mq.edu.au/~mjohnson/code/Restorer-README.txt)
|
|
|