Mining the meaningful term conjunctions from materialised faceted taxonomies: algorithms and complexity

Tzitzikas, Yannis; Analyti, Anastasia

doi:10.1007/s10115-005-0205-x

Cited by 11 publications

(20 citation statements)

References 15 publications

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“…satisfy condition (β = ), or reach to a compound terminology closer to S F e ) by an expression e with structure (parse tree) different than e. The answer is negative. At first note that previous work [21] has proved that if A is a subset of P(T ) such that Br(A) = A, then there is always an expression e such that S e = A. Moreover, we have shown that this is true, for every possible parse tree of e (i.e.…”

Section: Epiloguesupporting

confidence: 50%

“…The initial motivation for CTCA was to provide a well-founded method that is both flexible and economical (in terms of required input) and computationally efficient. One system based on CTCA has already been built [26], while other applications of CTCA are described in [20,22,21]. The semantics of CTCA differ from that of Description Logics (DL) [5] mainly because each operation of CTCA makes either a positive or a negative closed world assumption at its range, as it is shown in detail in [24].…”

Section: The Compound Term Composition Algebramentioning

confidence: 99%

“…it can enhance the robustness and usability of systems that are based on CTCA, like FASTAXON [26]. In addition, as a CTCA expression can be also used for exchanging compactly the compound terms that are extensionally valid according to a materialized faceted taxonomy (using the mining algorithms presented in [22,21]), this automation can be exploited in order to avoid reapplying these (computationally expensive) mining algorithms after an update of the faceted taxonomy. Moreover, as showed in [20,19], CTCA can be used for compressing a Symbolic Data Table [4].…”

Section: Introductionmentioning

confidence: 99%

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Evolution of faceted taxonomies and CTCA expressions

Tzitzikas

2006

Knowl Inf Syst

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A faceted taxonomy is a forest of taxonomies each describing the application domain from a different (preferably orthogonal) point of view. CTCA is an algebra that allows specifying the set of meaningful compound terms (meaningful conjunctions of terms) over a faceted taxonomy in a flexible and efficient manner. However, taxonomy updates may turn a CTCA expression e not wellformed and may turn the compound terms specified by e to no longer reflect the domain knowledge originally expressed in e. This paper shows how we can revise e after a taxonomy update and reach an expression e that is both well-formed and whose semantics (compound terms defined) is as close as possible to the semantics of the original expression e before the update. Various cases are analyzed and the revising algorithms are given. The proposed technique can enhance the robustness and usability of systems that are based on CTCA and allows optimizing several other tasks where CTCA can be used (including mining and compressing).

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Section: Epiloguesupporting

confidence: 50%

Section: The Compound Term Composition Algebramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evolution of faceted taxonomies and CTCA expressions

Tzitzikas

2006

Knowl Inf Syst

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“…The only constraint is that V should be an o-filter, that is if a compound term s is in V then all compound terms broader than s are also in V . Indeed, in [36], we show that for any compound terminology V that is an o-filter, there is a well-formed expression e of any expression form 3 such that S e = V .…”

Section: Algebraic Expressionsmentioning

confidence: 99%

“…Specifically, what he/she has to do is to formulate a CTCA expression e such that S e = V . Note that if we had a materialization of F that was "complete" -in the sense that the extension of every valid compound term is non-empty -then we could mine the expression e using the approach presented in [36] (this is called expression mining). However, we rarely have such a complete knowledge and certainly we do not have any materialization when we design the faceted taxonomy.…”

Section: Formulating the Expressionmentioning

confidence: 99%

An algebra for specifying valid compound terms in faceted taxonomies

Tzitzikas

Analyti

Spyratos

et al. 2007

Data & Knowledge Engineering

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A faceted taxonomy is a set of taxonomies, each describing a given knowledge domain from a different aspect. The indexing of the domain objects is done using compound terms, i.e. conjunctive combinations of terms from the taxonomies. A faceted taxonomy has several advantages over a single taxonomy, including conceptual clarity, compactness, and scalability. A drawback, however, is the cost of identifying compound terms that are invalid, i.e. terms that do not apply to any object of the domain. This need arises both in indexing and retrieval, and involves considerable human effort for specifying the valid compound terms one by one. In this paper, we propose and present in detail an algebra which can be used to specify the set of valid compound terms in an efficient and flexible manner. It works on the basis of the original simple terms of the facets and a small set of positive and/or negative statements. In each algebraic operation, we adopt a closed-world assumption with respect to the declared positive or negative statements. In this paper we elaborate on the properties of the algebraic operators and we describe application and methodological issues.

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Metadata Mechanisms: From Ontology to Folksonomy ... and Back

Christiaens

2006

On the Move to Meaningful Internet Systems 2006: OTM 2006 Workshops

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Mining the meaningful term conjunctions from materialised faceted taxonomies: algorithms and complexity

Cited by 11 publications

References 15 publications

Evolution of faceted taxonomies and CTCA expressions

Evolution of faceted taxonomies and CTCA expressions

An algebra for specifying valid compound terms in faceted taxonomies

Metadata Mechanisms: From Ontology to Folksonomy ... and Back

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