Semantic decision table
Encyclopedia
Semantic Decision Tables (SDT) use modern ontology engineering
(OE
) technologies to enhance traditional decision tables. The name "Semantic Decision Table" was coined by Yan Tang and Prof. Robert Meersman from VUB STARLab (Free University of Brussels
) in 2006. An SDT is a (set of) decision table(s) properly annotated with an ontology. It provides a means to capture and examine decision makers’ concepts, as well as a tool for refining their decision knowledge and facilitating knowledge sharing in a scalable manner.
. A decision table is defined as a "tabular method of showing the relationship between a series of conditions and the resultant actions to be executed". Following the de facto international standard (CSA, 1970), a decision table contains three building blocks: the condition
s, the actions (or decisions), and the rules.
A decision condition is constructed with a condition stub and a condition entry. A condition stub is declared as a statement of a condition. A condition entry provides a value assigned to the condition stub. Similarly, an action (or decision) composes two elements: an action stub and an action entry. One states an action with an action stub. An action entry specifies whether (or in what order) the action is to be performed.
A decision table separates the data (that is the condition entries and decision/action entries) from the decision templates (that are the condition stubs, decision/action stubs, and the relations between them). Or rather, a decision table can be a tabular result of its meta-rules.
Traditional decision tables have many advantages compared to other decision support manners, such as if-then-else programming statements, decision tree
s and Bayesian network
s. A traditional decision table is compact and easily understandable. However, it still has several limitations. For instance, a decision table often faces the problems of conceptual ambiguity and conceptual duplication; and it is time consuming to create and maintain large decision tables. Semantic Decision Tables are an attempt to solve these problems.
). The separation of an ontology
into extremely simple linguistic
structures (also known as lexons) and a layer of lexon constraints used by applications (also known as ontological commitments), aiming to achieve a degree of scalability
.
According to the DOGMA framework, an SDT consists of a layer of the decision binary fact types called SDT lexon
s and a SDT commitment layer that consists of the constraints and axioms of these fact types.
A lexon l is a quintuple <γ,t1,r1,r2,t2>. t1 and t2 represent two concepts in a natural language (e.g. English); r1 and r2 (in, r1 corresponds to “role” and r2 - “co-role”) refer to the relationships that the concepts share with respect to one another; γ is a context identifier refers to a context, which serves to disambiguate the terms t1, t2 into the intended concepts, and in which they become meaningful.
For example, a lexon <γ,driver's license, is issued to, has, driver> explains a fact that “a driver’s license is issued to a driver”, and “a driver has a driver’s license”.
The ontological commitment
layer formally defines selected rules and constraints by which an application (or “agent”) may make use of lexons. A commitment can contain various constraints, rules and axiomatized binary facts based on needs. It can be modeled in different modeling tools, such as Object Role Modeling
(ORM
), Conceptual Graph
, (CG
)) and Unified Modeling Language
(UML
).
Ontology engineering
Ontology engineering in computer science and information science is a new field, which studies the methods and methodologies for building ontologies: formal representations of a set of concepts within a domain and the relationships between those concepts....
(OE
Oe
Oe or OE may refer to:*Œ or œ, a ligature of o and e used in the modern French and medieval Latin alphabets*Oe *Open-mid front rounded vowel or *Ö*Ø*Ө, a letter in the Cyrillic alphabet*Ōe, Yamagata, a town of Japan...
) technologies to enhance traditional decision tables. The name "Semantic Decision Table" was coined by Yan Tang and Prof. Robert Meersman from VUB STARLab (Free University of Brussels
Free University of Brussels
The Free University of Brussels was a university in Brussels, Belgium. In 1969, it split into the Université Libre de Bruxelles and the Dutch-speaking Vrije Universiteit Brussel....
) in 2006. An SDT is a (set of) decision table(s) properly annotated with an ontology. It provides a means to capture and examine decision makers’ concepts, as well as a tool for refining their decision knowledge and facilitating knowledge sharing in a scalable manner.
Background
SDT is a decision tableDecision table
Decision tables are a precise yet compact way to model complicated logic.Decision tables, like flowcharts and if-then-else and switch-case statements, associate conditions with actions to perform, but in many cases do so in a more elegant way....
. A decision table is defined as a "tabular method of showing the relationship between a series of conditions and the resultant actions to be executed". Following the de facto international standard (CSA, 1970), a decision table contains three building blocks: the condition
Condition
-Logic:* Logical conditional* Necessary and sufficient condition, condition of another means that the former statement is true if and only if the latter is true-Computer programming:* Conditions, a generalization of exceptions in exception-handling...
s, the actions (or decisions), and the rules.
A decision condition is constructed with a condition stub and a condition entry. A condition stub is declared as a statement of a condition. A condition entry provides a value assigned to the condition stub. Similarly, an action (or decision) composes two elements: an action stub and an action entry. One states an action with an action stub. An action entry specifies whether (or in what order) the action is to be performed.
A decision table separates the data (that is the condition entries and decision/action entries) from the decision templates (that are the condition stubs, decision/action stubs, and the relations between them). Or rather, a decision table can be a tabular result of its meta-rules.
Traditional decision tables have many advantages compared to other decision support manners, such as if-then-else programming statements, decision tree
Decision tree
A decision tree is a decision support tool that uses a tree-like graph or model of decisions and their possible consequences, including chance event outcomes, resource costs, and utility. It is one way to display an algorithm. Decision trees are commonly used in operations research, specifically...
s and Bayesian network
Bayesian network
A Bayesian network, Bayes network, belief network or directed acyclic graphical model is a probabilistic graphical model that represents a set of random variables and their conditional dependencies via a directed acyclic graph . For example, a Bayesian network could represent the probabilistic...
s. A traditional decision table is compact and easily understandable. However, it still has several limitations. For instance, a decision table often faces the problems of conceptual ambiguity and conceptual duplication; and it is time consuming to create and maintain large decision tables. Semantic Decision Tables are an attempt to solve these problems.
Definition
SDT is modeled based on the framework of Developing Ontology-Grounded Methods and Applications (DOGMADOGMA
DOGMA, short for Developing Ontology-Grounded Methods and Applications, is the name of research project in progress at Vrije Universiteit Brussel's STARLab, Semantics Technology and Applications Research Laboratory...
). The separation of an ontology
Ontology
Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...
into extremely simple linguistic
Language
Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...
structures (also known as lexons) and a layer of lexon constraints used by applications (also known as ontological commitments), aiming to achieve a degree of scalability
Scalability
In electronics scalability is the ability of a system, network, or process, to handle growing amount of work in a graceful manner or its ability to be enlarged to accommodate that growth...
.
According to the DOGMA framework, an SDT consists of a layer of the decision binary fact types called SDT lexon
Lexon
Lexon, also known as the Burris-Brockmeyer Farm, is a historic home located at Centreville, Queen Anne's County, Maryland. It was constructed in the third quarter of the 18th century. It is a two story brick house with a pitched gable roof, center passage single pile plan...
s and a SDT commitment layer that consists of the constraints and axioms of these fact types.
A lexon l is a quintuple <γ,t1,r1,r2,t2>. t1 and t2 represent two concepts in a natural language (e.g. English); r1 and r2 (in, r1 corresponds to “role” and r2 - “co-role”) refer to the relationships that the concepts share with respect to one another; γ is a context identifier refers to a context, which serves to disambiguate the terms t1, t2 into the intended concepts, and in which they become meaningful.
For example, a lexon <γ,driver's license, is issued to, has, driver> explains a fact that “a driver’s license is issued to a driver”, and “a driver has a driver’s license”.
The ontological commitment
Ontological commitment
In the philosophy of language and metaphysics, an ontological commitment is said to be necessary in order to make a proposition in which the existence of one thing is presupposed or implied by asserting the existence of another. We are “committed” to the existence of the second thing, even though...
layer formally defines selected rules and constraints by which an application (or “agent”) may make use of lexons. A commitment can contain various constraints, rules and axiomatized binary facts based on needs. It can be modeled in different modeling tools, such as Object Role Modeling
Object role modeling
Object Role Modeling is a method for conceptual modeling, and can be used as a tool for information and rules analysis, ontological analysis, and data modeling in the field of software engineering.- Overview :...
(ORM
Orm
Orm became an Anglo-Saxon personal name during period of the Danelaw...
), Conceptual Graph
Conceptual graph
Conceptual graphs are a formalism for knowledge representation. In the first published paper on CGs, John F. Sowa used them to represent the conceptual schemas used in database systems...
, (CG
CG
CG, Cg or cg may stand for:*Airlines PNG IATA code*Categorial grammar*Constraint grammar*Carnival Games, a video game for Wii and Nintendo DS*Center of gravity*Centigram , a unit of mass in the metric system...
)) and Unified Modeling Language
Unified Modeling Language
Unified Modeling Language is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created, by the Object Management Group...
(UML
Unified Modeling Language
Unified Modeling Language is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created, by the Object Management Group...
).