Jyrki Niemi

Is it possible to create a very large wordnet in 100 days? An evaluation

Wordnets are large-scale lexical databases of related words and concepts, useful for language-aware software applications. They have recently been built for many languages by using various approaches. The Finnish wordnet, FinnWordNet (FiWN), was created by translating the more than 200,000 word senses in the English Princeton WordNet (PWN) 3.0 in 100 days. To ensure quality, they were translated by professional translators. The direct translation approach was based on the assumption that most synsets in PWN represent language-independent real-world concepts. Thus also the semantic relations between synsets were assumed mostly language-independent, so the structure of PWN could be reused as well. This approach allowed the creation of an extensive Finnish wordnet directly aligned with PWN and also provided us with a translation relation and thus a bilingual wordnet usable as a dictionary. In this paper, we address several concerns raised with regard to our approach, many of them for the first time. We evaluate the craftsmanship of the translators by checking the spelling and translation quality, the viability of the approach by assessing the synonym quality both on the lexeme and concept level, as well as the usefulness of the resulting lexical resource both for humans and in a language-technological task. We discovered no new problems compared with those already known in PWN. As a whole, the paper contributes to the scientific discourse on what it takes to create a very large wordnet. As a side-effect of the evaluation, we extended FiWN to contain 208,645 word senses in 120,449 synsets, effectively making version 2.0 of FiWN currently the largest wordnet in the world by these statistics.

HFST — A System for Creating NLP Tools

The paper presents and evaluates various NLP tools that have been created using the open source library HFST – Helsinki Finite-State Technology and outlines the minimal extensions that this has required to a pure finite-state system. In particular, the paper describes an implementation and application of Pmatch presented by Karttunen at SFCM 2011.

Extending and Updating the Finnish Wordnet

This paper presents simple methods for adding new words to a wordnet. We use the Finnish wordnet, FinnWordNet, as an example. We pay particular attention to high- and medium-frequency words thus far missing from FinnWordNet, and arrive at an estimate for the number of culture-specific words among them. We also find that the majority of the high- and medium-frequency words are compounds, which makes them relatively easy to add by using the head word of a compound to locate hypernym synset candidates. Another goal of ours is to add new synonyms to the existing synsets of FinnWordNet. We present a method that finds candidates for new synonyms from a bilingual lexical resource by exploiting the direct word sense translation correspondences between FinnWordNet and the Princeton WordNet. We apply the method to the interlanguage links between articles on the same topic in the Finnish and English Wikipedias on the one hand, and to the translations in the Finnish and English Wiktionaries on the other, and compare the results.

Modelling the Semantics of Calendar Expressions as Extended Regular Expressions

This paper proposes modelling the semantics of natural-language calendar expressions as extended regular expressions (XREs). The approach covers expressions ranging from plain dates and times of the day to more complex ones, such as thesecond Tuesdayfollowing Easter. Expressions denoting disconnected periods of time are also covered. The paper presents an underlying string-based temporal model, sample calendar expressions with their XRE representations, and possible applications in temporal reasoning and natural-language generation.

Ontology-based Knowledge in Interactive Maintenance Guide

This paper describes 4M, a language technology research project where a dialogue system is applied on a mobile platform in a maintenance job scenario. The human-machine interface uses speech synthesis and recognition, assisted with a hypertext display. We describe a modular agent architecture, composed of independent program components which are implemented by or communicate using ontology programming techniques. Domain content and lingware are developed and shared using standard Web ontology formats and ontology-aware offline tools. A contribution of the project is the attention paid to standardization to help provide the system with new content and to migrate it to new domains, languages and purposes

Two string-based finite-state models of the semantics of calendar expressions

This paper presents two string-based finite-state approaches to modelling the semantics of natural-language calendar expressions: extended regular expressions (XREs) over a timeline string of unique symbols, and a string of hierarchical periods of time constructed by finite-state transducers (FSTs). The approaches cover expressions ranging from plain dates and times of the day to more complex ones, such as the second Tuesday following Easter. The paper outlines the representations of sample calendar expressions in the two models, presents a possible application in temporal reasoning, and informally compares the models.

Pivotal synchronization languages : A framework for alignments

We propose pivotal synchronization languages (PSLs) that represent alignments of parallel processes. PSLs are closely related to synchronization languages [10], but the strings in PSLs are partitioned into sequences of pivots. In the partitioned representation, each pivot gathers and aligns simultaneous process boundaries (starts and terminations). The paper demonstrates that PSLs (and new join operators) provide a unified framework for implementing some independent formalisms. In particular, we show that at least two existing formalisms, generalized synchronization expressions [10] and interleave-disjunction-lockexpressions [8] have PSL-based counterparts. Furthermore, we sketch tentatively a new formalism that adapts the ideas of the operator of generalized restriction [11] to PSLs. All this suggests that the union of these formalisms might be implementable.