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The Potential of Ontologies for Courts. Erich Schweighofer University of Vienna, Austria* At present on leave, working for the European Commission. The expressed views are those of the author. Outline. Concept and aim of legal ontologies Legal ontologies: state of the art
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The Potential of Ontologies for Courts Erich Schweighofer University of Vienna, Austria* At present on leave, working for the European Commission. The expressed views are those of the author.
Outline • Concept and aim of legal ontologies • Legal ontologies: state of the art • Proposal of a comprehensive legal ontology • Steps to take: hybrid information system, lexical ontology, pre-ontology, dynamic electronic commentary • LOIS project • Potential for courts • Conclusions
Concept and aim of legal ontologies • Explicit formulation of a legal domain • Conceptual model • Abstract, simplified, computable • New form of abstraction and formalisation of law • Theory of formalisation (?) • Advantages • Computable • Links with world ontologies • Re-use of existing ontologies • Important tool for automation of law • Problems • High efforts required for knowledge acquisition • Scaling-up (well-known problem in AI & law)
Frames-Based Ontology • Frames-based ontology, van Kralingen and Visser • Common legal ontology; re-useable, 3 classes of model primitives, for each class a frame structure has been defined with all relevant attributes: • Norm: 8 elements (norm identifier, norm type, promulgation, scope, conditions of application, subject, legal modality, act identifier) • Act: 14 elements (act identifier, promulgation, scope, agent, act type, modality of means, manner, temporal and spatial aspects, circumstances, cause, aim, intentionality, final state) • Concept: 7 elements (concept, concept type, priority, promulgation, scope, conditions, instances) • Vocabulary: notions for actions, agents, objects, relations, properties, words indicating place, source, textual constructions, arithmetical operations and legal modality • Application: Dutch Unemployment Benefits Act • Good representation model, very different for scaling-up from a small ontology
Functional Ontology (1) • Functional ontology / Valente • Aim: organisation and linking of legal knowledge, in particular in respect to conceptual information retrieval • 6 basic categories of legal knowledge • Normative knowledge, meta-legal knowledge, world knowledge, responsibility knowledge, reactive knowledge, creative knowledge • Follow-up: • ON-LINE (architecture of legal case-solving) • CLIME/MILE (legal information server) • PROSA (training system for legal case-solving) • Problems: modelling of world knowledge; scaling-up
Functional Ontology (2) Functional Ontology / Valente
E-Court, LRI-Core (1) • Project E-Court/University of Amsterdam • Goal: semi-automated multi-lingual information management for various sources (audio, video, text); application area: penal law • Main functions: audio, video and text synchronisation, advanced IR, database management, workflow management, security management • LRI-Core: broad concept structure with typical legal main concepts • Basic assumptions: • Objects and processes are basic entities in the physical world • Mental entities behave mostly like physical objects • Communication is done over physical objects (documents) and actions (language) • Mental und physical world overlap in the concept of “agent” • Social order and processes consist of rules and functions that are implemented by identifiable agents as individual persons • Time and place have a two-dimensional status (position, supplementary attributes) • About 200 concepts, in development
E-Court, LRI-Core (2) Structure LRI-Core/E-Court University of Amsterdam
E-Court, LRI-Core (3) • Anchors • Links between foundational (upper) ontology (= world knowledge) and legal core ontology (legal concepts) • Support legal subsumption • Select/direct from various acts or agents to the legally relevant ones • Important aspect for improving legal commentaries
E-Power • E-Power, project of the Dutch Tax and Customs Administration • Application-oriented knowledge system; formalisation of laws and regulations as conceptual models • Automated tasks (e.g. subsumption, calculation, document assembly); comprehensive support from legislation to application • Unified Modeling Language (UML)/Object Contraint Model (OCL) • Prototype: Dutch income tax law; used by Fortis Banque, Belgium, and the Pension Administration of the Dutch Finance Ministry
Semantic links between words and meanings • Automated Text Analysis / Conceptual Indexing • Text corpora are analysed for legal meanings • Many projects, e.g. • KONTERM/LabelSOM/GHSOM (Schweighofer et al. 1993-), Vienna University/ Vienna University for Technology • FLEXICON (Smith et al. 1990-1997), University of British Columbia • SALOMON (Moens et al. 1997-), University of Leuven • SMILE (Brünninghaus/Ashley 1999-); University of Pittsburgh • Advantage: high knowledge in working with text corpora • Problems: knowledge acquisition, scaling-up from small applications
WordNet (1) • English lexical database • Linguist George Miller/Princetone University • http://www.cogsci.princeton.edu/~wn/ • EuroWordNet EWN • Goal: mono and cross-lingual information retrieval • WordNet lexica for different European languages, linked by an inter-lingual index (ILI) • Basis structure of the American WordNet • Extended seminatic-lexical relations (in particular synonymy, antonymy or hyponomy) • Three top level categories ("top-ontology" with 63 semantic distinctions – 1st, 2nd, 3rd Order Entity) -
WordNet (2) • form together the common semantic framework for all European languages http://www.illc.uva.nl/EuroWordNet/ • German variant: GermaNet http://www.sfs.nphil.uni-tuebingen.de/lsd/ • Global WordNet • Based on WordNet and European World Net http://www.globalwordnet.org • WordNet = world ontology or upper level ontology (?)
Proposal for a Comprehensive Ontology (1) • Real world (world knowledge) • Subjects = persons (agents) • Objects = things • Acts or omissions (intention, negligence), processes • Formalisation using existing world ontologies (zB WordNet or CYC) • Legal system as a order of norms : socio-economic governance by law with the goal of risk reduction • Formalisation with a frames-based ontology • Frames for subjects (agents), objects, acts, concepts, norms, anchors
Proposal for a Comprehensive Ontology (2) • Extension of norm frame: including evaluation criteria of the legal order • Purpose of legal order: risk reduction • Efficiency and reasonableness as essential criteria • Criteria (bench-marking) • How high is the probability of compliance? • How high is the probability of acceptance? • How strong is the law enforcement? • How high is the required control (surveillance and sanctions)? • How high is the risk of non-compliance? • How easy can be norm be understood? • How easy is the norm to be applied? • How good is the contribution to stabilisation of behaviour? (Luhmann)
Proposal for a Comprehensive Ontology (3) • Anchor frames • Subsumption between real world and legal system • Dynamic and electronic commentary replacing traditional paper commentary • Legal concepts linked with: • Norms • Formal rules • Application of law (procedures, execution) • Procedural charts • Material rules • Acts and omissions with legal consequences • Frames • Anchors • World ontology
Steps towards a Comprehensive Ontology • Start: information system (text archive) • Published, communicated and documented legal order; now in the form of a legal information and search machine • Hybrid knowledge-based system • Advanced vocabulary • Pre-ontology
Hybrid knowledge-based system • Concept proposed by Schweighofer (1996) • Information system should be transformed into such a system by (semi)automatic analysis • Norms as logical sentences or process diagrams (e.g. SoftLaw) • Classification (e.g. GHSOM, LabelSOM) • Cross-references (e.g. AustLII, SiteSeer) • Concept analysis (e.g. KONTERM) • Summaries (e.g. KONTERM, FLEXICON) • (Semi)automatic text analysis • Result: semantic description of the legal order; some “primitive” anchors to legal system and world knowledge
Advanced lexical ontologies • Vocabularies and thesauri, classifications • Anchors between world and legal order • Types • Verbal, non-verbal • Different levels of thesauri (lawyers, laymen, librarians) • Advantages • Reduction of world complexity • Description of structure of vocabulary: synonymy, homonymy, polysemy, antinomy, generic terms, sub terms • Linking of different linguistic levels • Linking of different languages • Legal input: Linking of legal concepts with facts (world knowledge)
LOIS Lexical Ontologies for legal Information Serving • 10 European partners (universities and enterprises) • Multi-lingual access to European legal databases • Formal representation of legal concepts in all languages on the basis of the WorldNet technology; similar concepts • 6 languages should be linked (synsets, EWN) • Italian, Dutch, Portuguese, German, Czech, English • Project duration: 24 months; result: 5000 synsets in each language • Further research: • Information retrieval: improved techniques • Document standards: common XML standard for the representation of legal documents • Commercial use of public sector information • Showcase Applications: test and demonstration purposes • Product integration: integration in commercial applications
Pre-ontology • Transformation of hybrid knowledge-based system in a frame structure for norms using advanced vocabularies • Norm frame (e.g. van Kralingen) • Type of norm (typology of Hohfeld or better Herrestad) • Links to the advanced vocabularies (e.g. for subsumption) • Links to concept frames • Concept frames • Extension: socio-economic description of norm (risk reduction)
Potential for Courts (1) • Improving existing legal information systems • Hybrid knowledge based system • Advances lexical ontologies • Improved access; better description • Pre-ontologies • Formalisation of laws and court decisions • Norms will be formalized in a frame-based structure • Procedures will be presented as procedural models
Potential for Courts (2) • Final goal: dynamic electronic commentary • Comprehensive description of the legal order • Precise links from legal concepts to world knowledge • Lexical ontologies • Dynamic and (semi)automatic description • Efficiency criteria for each norm (risk reduction) • Advantages • Better description of world and its legal consequences • Legal subsumption easier and quicker
Conclusions • Ontologies are the key for a computer-useable formalisation of the world and the legal system • Integration of all existing ontologies required • Comprehensive model necessary • Intermediate steps necessary: legal information system, hybrid knowledge system, thesauri, pre-ontologies • Ontology will be a new form of a legal commentary • Ontology will be comprehensive instrument of analysis of legal order; risk reduction is central element of efficiency evaluation