extraction of legal definitions from a japanese statutory corpus -- toward construction of a legal...

Extraction of Legal Definitions from a Japanese Statutory Corpus

-- Toward Construction of a Legal Term Ontology

Makoto Nakamura,Yasuhiro Ogawa and Katsuhiko Toyama

(Nagoya University)

First of all

There wasn’t an English version of Japanese statutes until 2009.

Some companies have their own database as the need arises...

Japanese Law Translation Database (JLT)

Released in 2009. Advanced user interface Problems

quantityquality

Problems of JLT

Quantity307/7,700 laws so far (<4%) (2009-2013)Revision control wrt amendment laws

QualityA number of translatorsDisunity of translation

law titles, legal terms, etc.specific expressions

Example: Law Titles

一般社団法人及び一般財団法人に関する法律(ippan shadan houjin oyobi ippan zaidan houjin ni kansuru houritsu) Act Concerning General Corporations and General Foundations Act on General Associations and Foundations Act on General Associations and Incorporated Foundations Act on General Incorporated Association and General

Incorporated Foundation Act on General Incorporated Associations and General

Incorporated Foundations

Insurance Business Act (Act No.105 of 1995)Article 148 (4) The provisions of Article 78 (Liability for Damages Pertaining to the Actions of the Representative) of the Act on General Incorporated Associations and General Incorporated Foundations shall apply mutatis mutandis to an Entrusting Company......

Example: Variations of Translations この法律は、公布の日から施行する。(kono houritsu wa koufu no hi kara shikou suru.)

This Act shall be enforced from the date of promulgation. This Act shall come into effect as from the date of promulgation. This Act shall come into effect as of the date of promulgation; This Act shall come into effect as of the day of its promulgation. This Act shall come into effect on the day of promulgation. This Act shall come into force as from the date of its promulgation. This Act shall come into force as from the day of its promulgation. This Act shall come into force as of the date of its promulgation. This Act shall come into force as of the day of promulgation. This Act shall come into force from the day of promulgation. This Act shall enter into force on the day of its promulgation.

Problem of Quality

Law titles in different ways for citation A variety of translations

An identical expression should have an identical translation for the sake of the conservation of meaning.

Need of a translation dictionary

Translation tools

Terminology (dictionary)unification of translation4,482 entries at the latest version

Ontologysystematic translation

Translation Memory (Sekine et al., 2012) Statistical Machine Translation

(Ogawa et al., 2013) Tomorrow!!

Purpose

to construct a legal term ontology to provide legal terms and their

explanations

Approach automatic extraction application of natural language processing

Problems in This Study

1. What are legal terms?

2. Difficulty of Japanese text processing in the legal domain

3. Absence of a statutory corpus

1. What Are Legal Terms?Classification

1. Law titles2. Legal definitions3. Words in definitions4. Important terms

frequently used content words characteristic words

5. All words in laws

Our target

ガス事業法（昭和二十九年法律第五十一号）第二条この法律において「一般ガス事業」とは、一般の需要に応じ導管によりガスを供給する事業をいう。

Gas Business Act (Act No.51 of 1954)Article 2 The term “General Gas Utility Business” as used in this Act shall mean the business of supplying gas via pipelines to meet general demand.

1. What Are Legal Terms?Legal Definitions

are explicitly defined in a law. consist of tuples of a defined term and its

explanation.

2. Difficulty of Japanese Legal Text Processing

NLP tools: low performancespecial termssyntactic rules peculiar to the legal domainoutdated characters

Simple methods for surface pattern recognition: sufficientfrequent use of boilerplate expressions

3. Compilation of aJapanese Statutory Corpus includes all of the Japanese statutes consists of 9,915 acts that have been

enacted up to 2012 since promulgation of the new constitution of Japan in 1947

includes OCR errors doesn’t follow

error correction, or consolidation by amendment laws

Solutions of the Problems

1. What are legal terms?→ We focus on legal definitions.

2. Difficulty of Japanese text processing in the legal domain→ Simple methods work effectively.

3. Absence of a statutory corpus→ We compiled a large corpus.

Extraction Method

Simple pattern match from a legal texta) for independent sentences for definition

a sentence for definition itemization

b) for expressions parenthesized in a sentence an expression for definition the region of its explanation

a) Example of Surface Pattern Rules

Input text:ガス事業法第二条この法律において「一般ガス事業」とは、一般の需要に応じ導管によりガスを供給する事業をいう。１０この法律において「ガス事業」とは、一般ガス事業、簡易ガス事業、ガス導管事業及び大口ガス事業をいう。

Gas Business ActArticle 2-1 The term “General Gas Utility Business” as used in this Act shall mean the business of supplying gas via pipelines to meet general demand.Article 2-10 The term “Gas Business” as used in this Act shall mean a General Gas Utility Business, Community Gas Utility Business, Gas Pipeline Service Business or Large-Volume Gas Business.

Pattern of Definitions (6 rules)/ 「 (.+) 」とは、 (.+)( を、 | をいい、 | をいう。 | といい、 | という。 | とする。 )//”(.+)” (as used in this Act)? (shall mean|means) (.+)./

a) Example of Surface Pattern Rules for Itemization

Input text:介護保険法第七条６この法律において「医療保険各法」とは、次に掲げる法律をいう。健康保険法船員保険法・・・

Long-Term Care Insurance ActArticle 7 (6) The term “Medical Insurance Acts” as used in this Act means the following acts:(i) Health Insurance Act(ii) Seaman’s Insurance Act .....

Pattern of Definitions for Itemization (8 rules)/( 次 | 左 | 式 )( の ( 各号 | いずれか ))? に ( 掲げる | 定める )//the following/

b) Example of Surface Pattern Rules for Parenthesized Definitions

Input text:民事訴訟法第三十条４第一項又は前項の規定により原告又は被告となるべき者を選定した者（以下「選定者」という。）は、その選定を取り消し、又は選定された当事者（以下「選定当事者」という。）を変更することができる。

Code of Civil ProcedureArticle 30 (4) Persons who have appointed a party to stand as a plaintiff or defendant pursuant to the provisions of paragraph (1) or the preceding paragraph (hereafter referred to as “appointers”) may rescind the appointment or change the party thus appointed (hereafter referred to as the “appointed party”).

Pattern of Parenthesized Definitions/ （ (.+?) 「 (.+) 」と ( いう。 | 総称する。 ) ） //((.+?) referred to as “(.+)”)/

b) Extraction of Explanations

• Extracting an explanation corresponds to finding its starting point.

• Explanations are likely to start from the beginning of the sentence.

• We restrict our target to extraction of explanations satisfying this condition.

Easy!民事訴訟法第三十条４第一項又は前項の規定により原告又は被告となるべき者を選定した者（以下「選定者」という。）は、その選定を取り消し、又は選定された当事者（以下「選定当事者」という。）を変更することができる。

Difficult!If there is a parenthesis for a definition within 120 letters from the beginning without a comma or period, its explanation is from the beginning to the last letter before the parenthesis.

Experiments

Extraction of legal terms and their explanations from:independent sentences for definitionparenthesized expressions in a sentence

The statutory corpus3,131 / 9,915 statutesw/o all laws concerning amendment and repeal

of pre-existing laws

Evaluation: precision and recall

Evaluation Method

Legal terms1) as precise as possible2) as many as possible

Evaluation1) Precision

2) Recall

A B

C

Grey: the search space

A: system’s response

B: actual legal terms

C: correct answers

Statutory Corpus

=|C|

|A|

=|C|

|B|

Experimental Result

Definitions # of Tokens

# of Types

Precision Recall

in provisions 5,250 3,799 0.980 0.980

in parenthesis 9,624 6,030 0.850 0.396

Multiple defined terms

Japanese English # of laws

in provisions 中小企業者 small and medium sized enterprise operator

53

老年者 senile 22

in parenthesis

旧法 former act 178

施行日 effective date 122

Legal Terms Extracted from the Electricity Business Act

Defined terms Explanatory sentences

Electricity Business General Electricity Business and Wholesale Electricity Business

Electricity Utility General Electricity Utility and Wholesale Electricity Utility

Wholesale Electricity Business Business supplying a General Electricity Utility with electricity to be used for its General Electricity Business for which the Electric Facilities that satisfy the requirements specified by an Ordinance of the Ministry of Economy, Trade and Industry are used

Wholesale Electricity Utility Person who has obtained a license under paragraph 1 of the next Article to conduct a Wholesale Electricity Business

General Electricity Business Business supplying electricity to meet general demand

General Electricity Utility Person who has obtained a license under paragraph 1 of the next Article to conduct a General Electricity Business

Designated Electricity Utility Electricity Utility designated by an Ordinance of the Minister of International Trade and Industry

General Electricity Business Company

Company for General Electricity Utilities

Electric Facilities Machines, apparatuses, dams, waterways, reservoirs, electric lines, and other facilities installed for the purpose of generating, transforming, transmitting, distributing or using electricity (excluding, however, those installed in ships, vehicles or aircrafts, and those specified by a Cabinet Order)

Electric Facilities for General Use

Electric Facilities for receiving electricity from another person at a voltage lower than that specified by an Ordinance of the Ministry of Economy, Trade and Industry and using the electricity thus received at the same premises where it has been received (including Small Capacity Generation Facilities installed in the same premises and electrically connected with such Electric Facilities), which are electrically connected with Electric Facilities installed outside the premises only via the electric lines used for receiving electricity

Electric Facilities for Private Use

Electric Facilities other than Electric Facilities used for an Electricity Business and Electric Facilities for General Use

A Semantic Network of Inclusive relations

Electricity Business

Electricity Utility

Wholesale Electricity Business

Wholesale Electricity Utility

General Electricity Business

General Electricity Utility

Designated Electricity Utility

General Electricity Business Company

Electric Facilities

Electric Facilities for General Use

Electric Facilities for Private Use

# of nodes # of edges

38,974 26,969

Conclusion and Future Work

Legal terms and their explanationsover 14,000 terms with high precisionlow recall rate for the process of parenthesisapplicable for any language

Toward legal term ontologyinclusive relation among explanationssystematic translation

Future worksanaphora resolution

Thank you!!

Legal Terms Referring to the Term “Gas Business”

Legal Term The title of Act

ガス事業Gas Business

Gas Business Act (Act No.51 of 1954)

ガス工作物Gas Facilities

Gas Business Act (Act No.51 of 1954)

料金(gas) rate

Local Tax Act (Act No.226 of 1950

特定ガス消費機器Specified Gas Appliance

Act concerning Supervising Installation Work of Specified Gas Appliance (Act No.33 of 1979)

公益事業者public benefit service operator

Special Measures Act on Preparation, etc. for Common-Use Tunnel (Act No.81 of 1963)

地方公営企業local public enterprise

Act on Labor Relations of Local Public Enterprises (Act No.289 of 1952)

事業者business operator

Enterprise Rationalization of Promotion Act (Act No.5 of 1952)

Patterns of Definitions-- Insert Statements in Parenthesis

Defined term Explanatory sentence

(a) in parenthesis before parenthesis

A Gas Utility Service Provider or a Wholesale Gas Business Supplier (these persons shall hereinafter be referred to as a “Gas Utility, etc.”) may, ...

(b) before parenthesis in parenthesis

In the prisoner of war camp, chaplains, etc. (i.e. chaplains, and prisoners of war who are permitted to engage in works listed in item (iv) of Article 64 pursuant to the provision of Article 69. The same shall apply in paragraph (3) of Article 84) may ...

Patterns of Definitions

An independent provision

An insert statement in parenthesis



An insert statement in parenthesis





An insert statement in parenthesisガス事業法（昭和二十九年法律第五十一号）第四十二条ガス事業者又は卸供給事業者（以下「ガス事業者等」という。）は、その事業のように供するため、．．．

Gas Business Act (Act No.51 of 1954)Article 42 A Gas Utility Service Provider or a Wholesale Gas Business Supplier (these persons shall hereinafter be referred to as a “Gas Utility, etc.”) may, when it is necessary to install pipelines on or under a road, bridge, ditch, river, embankment or other public land in order to use such pipelines for the businesses, use them with permission from the administrator thereof to the extent that such use does not impair their usability.

a) Independent Sentence for Definition




ガス事業法（昭和二十九年法律第五十一号）第四十二条ガス事業者又は卸供給事業者（以下「ガス事業者等」という。）は、その事業のように供するため、道路、橋、みぞ、河川、堤防その他公共の用に供せられる土地の地上又は地中に導管を設置する必要があるときは、その効用を妨げない限度において、その管理者の許可を受けて、これを使用することができる。

Gas Business Act (Act No.51 of 1954)Article 42 A Gas Utility Service Provider or a Wholesale Gas Business Supplier (these persons shall hereinafter be referred to as a “Gas Utility, etc.”) may, when it is necessary to install pipelines on or under a road, bridge, ditch, river, embankment or other public land in order to use such pipelines for the businesses, use them with permission from the administrator thereof to the extent that such use does not impair their usability.


武力攻撃事態における捕虜等の取り扱いに関する法律（平成十六年法律第百十七号）第四十二条宗教要員等（宗教要員及び第六十九条の規定により第六十四条第四号に掲げる業務に従事することを許された捕虜をいう。第八十四条第三項において同じ。）は、捕虜収容所内に置いて，被収容者の行う第四十条に規定する宗教上の行為を補助し，又は前条第一項に規定する宗教上の儀式を行うことができる。

Act on Treatment of Prisoners of War and Other Detainees in Armed Attack Situations (Act No.117 of 2004)Article 42 In the prisoner of war camp, chaplains, etc. (i.e. chaplains, and prisoners of war who are permitted to engage in works listed in item (iv) of Article 64 pursuant to the provision of Article 69. The same shall apply in paragraph (3) of Article 84) may assist the detainees in performing religious acts prescribed in Article 40 and may perform the religious ceremonies prescribed in paragraph (1) of the preceding Article.


武力攻撃事態における捕虜等の取り扱いに関する法律（平成十六年法律第百十七号）第百八条２審査会は、資格認定審査請求をしたもの（以下「資格認定審査請求人」という。）が前項の期間内に補正をしないときは、裁決をもって、資格認定審査請求を却下することができる。ただし、その不適法が軽微なものであるときは、この限りでない。

Act on Treatment of Prisoners of War and Other Detainees in Armed Attack Situations (Act No.117 of 2004)Article 108 (2) In the case that a person who has appealed for a review on the recognition of internment status (hereinafter referred to as “the applicant of the appeal for review on the recognition of internment status”) fails to correct the defect within the period set forth in the preceding paragraph, the Review Board may dismiss the appeal for review on the recognition of internment status by determination; provided, however, that this shall not apply when such defect is minor.

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