Japanese Input Processors Chain

Introduction

An Input Processor (IP) pre-processes inputs for the Teneo Engine to be able to perform different processes on them, such as normalization and tokenization, for example. Each language supported by the Teneo Platform has a chain of Input Processors that know how to process that particular language.

The Japanese Input Processors chain implemented in Teneo 5.1.1 is backwards incompatible with the Japanese Teneo Lexical Resource and solutions of former Teneo versions due to different tokenization.

IP Chain Setup

The following graph displays the setup of the Japanese Input Processors chain; each Input Processor is described further in the following sections.

Japanese Simplifier

The Japanese Simplifier is a special kind of processor that is used to normalize the user input by:

• converting full width Latin letters and Arabic digits into their half width version, and
• lowercasing the uppercase Latin letters.

This Simplifier is special because it is not run as part of the Input Processors chain, but rather by the Tokenizer when it puts the tokens generated by Kuromoji into a Teneo data structure. Additionally, the Simplifier is also run by the condition parser inside the Teneo Engine, which normalizes the Language Object syntax words before adding them to the internal Engine dictionary.

Input Processors

Japanese Tokenizer

The Japanese Tokenizer, which performs sentence segmentation and tokenization, runs Kuromoji (Japanese tokenizer) on raw input strings and then processes the tokens returned by Kuromoji into words and sentences for Teneo. Since the tokenization of Kuromoji is too aggressive for the purpose of Teneo, the processing of the tokens involves a set of hard-coded rules that concatenate some of the tokens into bigger units.

Please note the distinction in the terminology:
A token is a object returned by Kuromoji and an element of the original presentation.
In the Teneo Platform, the words that are used in the Platform are referred to as words, which might be the concatenation of several Kuromoji tokens.

In the exceptional case of the Japanese interpunct symbol “·”, the Japanese Tokenizer also splits tokens from Kuromoji.

The concatenation is done by a separate helper class JapaneseConcatenator which is instantiated for each input. The functionality of concatenation and sentence segmentation is exclusively implemented in that class. The concatenation rules are hard-coded and process a sequence from left to right, deciding whether the observed tokens should be concatenated and if a new sentence should be started.

When a word object is created, the features from the Kuromoji tokens that form part of that word are passed into the property map. Those features are then retrieved from the property map of each word by the Japanese Annotator.

The concatenation of the Japanese Tokenizer can be overridden by introducing entries into the solution dictionary (i.e. in a language object) that follow the below pattern:

1DICTEXT_tok_lemma
2

In other words, entries that have the prefix DICTEXT will be considered by the concatenator and the token tok will never be concatenated, i.e. will be a standalone word that will have the lemma annotation lemma.

Splitting of Tokens with Numbers

As of Teneo 6, in order to cater for date and time recognition in Japanese, the Japanese Tokenizer splits tokens that contain slashes, dashes, tildes, colons, commas, dots and interpuncts in certain contexts, as detailed below:

• Splits numbers from slashes and keep the slash as a separate token if there are at least two slashes in-between numbers, e.g. 25/04/2020, but not when there is a single slash between numbers as that is a fraction that the Number Recognizer should recognize, e.g. 2/3.
• Splits numbers from dashes, tildes and interpuncts and keep them as separate tokens, e.g. 25 - 04 - 2020, 25 ~ 04 ~ 2020, 25 ・ 04 ・ 2020.
• Splits numbers from dots and keep the dots as separate tokens, e.g. 25 . 04 . 2020; but not when there is a single dot between numbers as in that case the dot could be a decimal marker for numbers, e.g. 1.5.
• Splits numbers from comma and keep the comma as a separate token, e.g. 2,3; but not when there are three digits after the comma as in that case the comma could be a thousands separator for numbers, e.g. 1,000.
• Splits numbers from colons and keep the colon as a separate token, e.g. 10 : 30
• Splits special number tokens that Kuromoji doesn't split, e.g. ２人 or ２，３.

Japanese Annotator

The Japanese Annotator creates annotations related to lemma, Part-of-Speech (POS), morphosyntactic information and named entities by processing each word one by one and for each Kuromoji token that forms part of a word, i.e., forms part of the concatenation, it goes through the list of annotation rules and produces the annotations if the rules match on the context of the current token.

The context of the current token can be the features themselves returned by Kuromoji for that token, such as the POS tag or the lemma, or they can be the annotations that were assigned to the previous token in the same word, if applicable. Note that the context of the first token contains NULL as previous annotation.

The Japanese Annotator creates annotations of the following types:

• Lemma (the lemma of a word is provided as an annotation if available)
• Part-of-Speech (POS) information
• Morphosyntactic information
• Named-entity information.

Annotations in Teneo

The following Part-of-Speech, morphosyntactic and named-entity annotations may be generated by the Japanese Annotator. Note that a token can have multiple annotations. The annotations carry one of the following suffixes to distinguish their type: POS, MST, or NER.

For information related to the ANNOT Language Objects available in the Japanese Lexical Resource, please see the lists of POS/MST ANNOT language objects and/or NER ANNOT language objects for Japanese.

Japanese Number Recognizer

The Japanese Number Recognizer is capable of recognizing the following types of number expressions:

• Arabic numbers
• Formal and colloquial Kanji numbers
• Hiragana numbers
• Numbers with counters not split from the actual numeric expression
• Numbers with factors both larger and smaller than zero
• Decimal numbers
• Fractions.

When a number expression is detected in a user input, the following annotation is created with a variable which holds the found number.

System Annotation

Teneo bundles two default collections of annotations in all language configurations: standard annotations added by the System Annotation Input Processor and special system annotations added by the Engine; the System Annotation Input Processor performs simple analysis of the sentence text and may generate the standard annotations listed below.

Special System Annotations

The following two, special annotations are set by the Teneo Engine. These special system annotations are not related to individual inputs but rather to whole dialogues and are dependent on the session state.

Language Detector

The Language Detector uses a machine learning model to predict the language of a given user input and adds an annotation, as seen in below table, to the input together with a confidence score of the prediction.

The Language Detector can predict the following 45 languages; the language label used to create the annotation name is in brackets:

Arabic (AR), Bulgarian (BG), Bengali (BN), Catalan (CA), Czech (CS), Danish (DA), German (DE), Greek (EL), English (EN), Esperanto (EO), Spanish (ES), Estonian (ET), Basque (EU), Persian (FA), Finnish (FI), French (FR), Hebrew (HE), Hindi (HI), Hungarian (HU), Indonesian-Malay (ID_MS), Icelandic (IS), Italian (IT), Japanese (JA), Korean (KO), Lithuanian (LT), Latvian (LV), Macedonian (MK), Dutch (NL), Norwegian (NO), Polish (PL), Portuguese (PT), Romanian (RO), Russian (RU), Slovak (SK), Slovenian (SL), Serbian-Croatian-Bosnian (SR_HR), Swedish (SV), Tamil (TA), Telugu (TE), Thai (TH), Tagalog (TL), Turkish (TR), Urdu (UR), Vietnamese (VI) and Chinese (ZH).

Serbian, Bosnian and Croatian are treated as one language under the label SR_HR, and Indonesian and Malay are treated as one language under the label ID_MS

A number of regexes are also in use by the Input Processor, helping the model to not predict a language for fully numerical inputs, URLs or other type of nonsense inputs.

The Language Detector will provide an annotation when the confidence prediction threshold is above 0.2 for the languages, but for the following listed languages, language annotations are always created (even for predictions below 0.2) since the Language Detector is mostly accurate when predicting them: Arabic, Bengali, Greek, Hebrew, Hindi, Japanese, Korean, Tamil, Telugu, Thai, Chinese, Vietnamese, Persian and Urdu.

Predict

The Predict Input Processor makes use of an intent model generated when classes are available in a Teneo Studio solution to annotate user inputs with the defined classes; intent models can be generated either with Teneo Learn or CLU. Note that as of Teneo 7.3, deferred intent classification is applied and annotations are only created by Predict if references to class annotations are found during the input matching process.

When Predict receives a user input, confidence scores are calculated for each class based on the model and annotations created for the most confident class and for each other class that matches the following criteria:

• the confidence is above the minimum confidence (defaults to 0.01)
• the confidence is higher than 0.5 times the confidence value of the top class.

For each selected class, an annotation with the scheme <CLASS_NAME>.INTENT is created, with the value of the model's confidence in the class as well as an annotation variable specifying the used classifier (i.e., Learn, CLU or LearnFallback) and an Order variable defining the order of the selected classes (i.e., 0 for the class with the highest confidence score and 4 for the selected class with the lowest confidence score).
A special annotation <CLASS_NAME>.TOP_INTENT is created for the class with the highest confidence score.

The Predict Input Processor creates a maximum of 5 annotations, regardless of how many classes match the criteria.

Date Time Recognizer

The Date Time Recognizer available in the Japanese input processing chain recognizes and annotates various date and/or time expressions which are then used by language objects to support the date and time interpretation; the following annotations - with the listed variables - are created by the Date Time Recognizer.

To read more about how to use the native understanding and interpretation of date and time expressions in the Teneo Platform, please see here.