RuleOMS: A Rule-Based Online Management System

RuleOMSA Rule-Based Online Management System

Mohammad Badiul Islam and Guido Governatori

10 October 2015

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Research Question

How to take decisions based on data and norms

1 data is retrieved from (relational) database

2 reasoning with norms

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Research Question

How to take decisions based on data and norms

1 data is retrieved from (relational) database

2 reasoning with norms

RuleOMS Copyright NICTA 2015 Mohammad Badiul Islam and Guido Governatori 2/14

Reasoning with Norms

Contract fragment

3.1 A “Premium Customer” is a customer who has spent more that $10000 in goods.

3.2 Services marked as “special order” are subject to a 5% surcharge. Premium customersare exempt from special order surcharge.

5.2 The (Supplier) shall on receipt of a purchase order for (Services) make them availablewithin one day.

5.3 If for any reason the conditions stated in 4.1 or 4.2 are not met the (Purchaser) is entitledto charge the (Supplier) the rate of $100 for each hour the (Service) is not delivered.

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Requirements for Reasoning with Norms

• modelling deontic concepts• Obligations• Prohibitions• Permissions• Violations

• modelling exceptions

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Querying Relational Databases

SQL

• set-theory

• first-order logic

• datalog

first-order logic not appropriate to model norms (Herrestad, ICAIL1991)

RuleOMS Copyright NICTA 2015 Mohammad Badiul Islam and Guido Governatori 5/14

Querying Relational Databases

SQL

• set-theory

• first-order logic

• datalog

first-order logic not appropriate to model norms (Herrestad, ICAIL1991)

RuleOMS Copyright NICTA 2015 Mohammad Badiul Islam and Guido Governatori 5/14

Once upon a time in a landfar far away . . .

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Why Defeasible Deontic Logic

Rule-based non-monotonic formalism

• Flexible

• Efficient (linear complexity)

• Directly skeptic semantics

• Argumentation semantics

• Constructive proof theory

• Encompasses other formalisms used in AI and Law

• Applied in several fields/optimised implementations

• Extensible

• Efficient implementations (SPINdle)

• Not affected by Deontic Logic Paradoxes

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Defeasible Deontic Logic Blueprint

Combination of an efficient non-monotonic logic (defeasible logic) and a deontic logic ofviolation.

• Facts are indisputable statements.

• Defeasible rules are rules that can be defeated by contrary evidence.

a1, . . . , an ⇒ c

• The superiority relation is a binary relation defined over the set of rules. The superiorityrelation determines the relative strength of two (conflicting) rules.

Extended with deontic operators O, P, F ,⊗, obligation, permission, prohibition, violation(binary)

a1, . . . , an ⇒ Ob1 ⊗ · · · ⊗ Obm

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Reasoning with Defeasible Logic

1 A is a fact; or2 there is an applicable rule for A, and either

1 all the rules for ¬A are discarded (i.e., not applicable) or2 every applicable rule for ¬A is weaker than an applicable rule for A.

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RuleOMS Idea

• Facts: SQL queries from Databases

• Rules: Defeasible from Norms

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RuleOMS Architecture

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From SQL to Facts

{"predicate":"beingChild","SQL":"SELECT * FROM tblchildren WHERE

tblchildren.child_crn = $id ANDtblchildren.child_dob >= ${today - 15y}"}

RuleOMS Copyright NICTA 2015 Mohammad Badiul Islam and Guido Governatori 12/14

Conclusions

• Developed as part of Child At Risk project

• Modelled NSW Mandatory Reporter Guidelines

• Working on performance evaluation

• Planned to be released as open source soon

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Questions?

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