Tomoyuki Kajiwara

Evaluation Dataset and System for Japanese Lexical Simplification

We have constructed two research resources of Japanese lexical simplification. One is a simplification system that supports reading comprehension of a wide range of readers, including children and language learners. The other is a dataset for evaluation that enables open discussions with other systems. Both the system and the dataset are made available providing the first such resources for the Japanese language.

Controlled and Balanced Dataset for Japanese Lexical Simplification

We propose a new dataset for evaluating a Japanese lexical simplification method. Previous datasets have several deficiencies. All of them substitute only a single target word, and some of them extract sentences only from newswire corpus. In addition, most of these datasets do not allow ties and integrate simplification ranking from all the annotators without considering the quality. In contrast, our dataset has the following advantages: (1) it is the first controlled and balanced dataset for Japanese lexical simplification with high correlation with human judgment and (2) the consistency of the simplification ranking is improved by allowing candidates to have ties and by considering the reliability of annotators.

Building a Non-Trivial Paraphrase Corpus Using Multiple Machine Translation Systems.

We propose a novel sentential paraphrase acquisition method. To build a wellbalanced corpus for Paraphrase Identification, we especially focus on acquiring both non-trivial positive and negative instances. We use multiple machine translation systems to generate positive candidates and a monolingual corpus to extract negative candidates. To collect nontrivial instances, the candidates are uniformly sampled by word overlap rate. Finally, annotators judge whether the candidates are either positive or negative. Using this method, we built and released the first evaluation corpus for Japanese paraphrase identification, which comprises 655 sentence pairs.